Article

Mechoulam R, Ben-Shabat S, Hanus L, Ligumsky M, Kaminski NE, Schatz AR, Gopher A, Almog S, Martin BR, Compton DR, Pertwee RG, Griffine G, Bayewitch M, Barg J & Vogel Z.Identification of an endogenous 2-monoglyceride, present in canine gut, thatbinds to cannabinoid receptors. Biochem Pharmacol 50: 83−90

Authors:
  • School of Pharmacy, Ein Kerem Campus, Hebrew University of Jerusalem
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

In this study, we report the isolation from canine intestines of 2-arachidonyl glycerol (2-Ara-Gl). Its structure was determined by mass spectrometry and by direct comparison with a synthetic sample. 2-Ara-Gl bound to membranes from cells transiently transfected with expression plasmids carrying DNA of either CB1 or CB2—the two cannabinoid receptors identified thus far—with Ki values of 472 ± 55 and 1400 ± 172 nM, respectively. In the presence of forskolin, 2-Ara-Gl inhibited adenylate cyclase in isolated mouse spleen cells, at the potency level of Δ9-tetrahydrocannabinol (Δ9-THC). Upon intravenous administration to mice, 2-Ara-Gl caused the typical tetrad of effects produced by THC: antinociception, immobility, reduction of spontaneous activity, and lowering of the rectal temperature. 2-Ara-Gl also shares the ability of Δ9-THC to inhibit electrically evoked contractions of mouse isolated vasa deferentia; however, it was less potent than Δ9-THC.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Individual components of the endocannabinoid system have been intensively studied in recent decades and evaluated as potential targets of pharmacological interventions in systemic tumour therapy. N-arachidonoylethanolamine (anandamide, AEA) and 2-arachidonoylglycerol (2-AG) were the first lipids discovered as endogenously synthesised agonists at cannabinoid receptors [1,2]. Other endogenously formed cannabinoid compounds are 2-arachidonoylglycerol ether (noladin ether, 2-AGE) [3], N-arachidonoyldopamine (NADA) [4] and O-arachidonoylethanolamine (virodhamine) [5]. ...
... In one study, low FAAH and MAGL immunoreactivities in cancer cells were correlated with shorter patient survival [86]. Accordingly, in this work, median survival with low FAAH levels in cancer cells was 10 months, whereas patients with moderate to [54] CB 2 mRNA expression as prognostic factor for colon but not for rectal cancer; five-year overall survival for patients without CB 2 [71] Clinical prognosis for the MAGL high group markedly poorer than that for the MAGL low group in the 1-, 3-, and 5-year overall survival times and recurrence rates ○ [72] Lung cancer Lung adenocarcinoma patients with high CB2 level showed a shorter overall survival ○ [75] Patients with high expression levels of CB1, CB2 and CB1/CB2 showed increased survival ○ ○ [76] Overall survival gradually reduced with increasing ABHD6 levels; no significant association with MAGL expression ↔ [77] High MAGL expression associated with worse outcomes ○ [78] Mobile tongue squamous cell carcinoma High CB1 and CB2 expression associated with longer overall and disease-free survival times ○ ○ [83] Pancreatic cancer Correlation between longer survival and low CB1 receptor or high FAAH as well as MAGL levels; no correlation between survival and CB2 immunoreactivity ○ ↔ ○ ○ [86] Prostate cancer High CB1 expression associated with a shorter survival time ○ [89] High tumour epithelial FAAH associated with a poor disease-specific survival ○ [91] Renal cell carcinoma Higher CB2 expression tending to have poor clinical outcomes in survival analyses ○ [95] ○, higher expression is associated with poorer survival (or vice versa: lower expression is associated with prolonged survival); ○, lower expression is associated with poorer survival (or vice versa: higher expression is linked with prolonged survival); ↔, no association of the indicated parameter with patients' survival; CB1, CB2, cannabinoid receptor 1 or 2; FAAH, fatty acid amide hydrolase; HER2, human epidermal growth factor receptor 2; MAGL, monoacylglycerol lipase. ...
... Patients with high expression levels of CB 1 , CB 2 [71] Clinical prognosis for the MAGL high group markedly poorer than that for the MAGL low group in the 1-, 3-, and 5-year overall survival times and recurrence rates ○ [72] Lung cancer Lung adenocarcinoma patients with high CB2 level showed a shorter overall survival ○ [75] Patients with high expression levels of CB1, CB2 ...
Article
Full-text available
Despite the long history of cannabinoid use for medicinal and ritual purposes, an endogenous system of cannabinoid-controlled receptors, as well as their ligands and the enzymes that synthesise and degrade them, was only discovered in the 1990s. Since then, the endocannabinoid system has attracted widespread scientific interest regarding new pharmacological targets in cancer treatment among other reasons. Meanwhile, extensive preclinical studies have shown that cannabinoids have an inhibitory effect on tumour cell proliferation, tumour invasion, metastasis, angiogenesis, chemoresistance and epithelial-mesenchymal transition (EMT) and induce tumour cell apoptosis and autophagy as well as immune response. Appropriate cannabinoid compounds could moreover be useful for cancer patients as potential combination partners with other chemotherapeutic agents to increase their efficacy while reducing unwanted side effects. In addition to the direct activation of cannabinoid receptors through the exogenous application of corresponding agonists, another strategy is to activate these receptors by increasing the endocannabinoid levels at the corresponding pathological hotspots. Indeed, a number of studies accordingly showed an inhibitory effect of blockers of the endocannabinoid-degrading enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) on tumour development and spread. This review summarises the relevant preclinical studies with FAAH and MAGL inhibitors compared to studies with cannabinoids and provides an overview of the regulation of the endocannabinoid system in cancer.
... 2-AG was found to be present at 170 times higher concentrations than AEA in brain lysate [308]. While AEA was initially detected in the brain [135] and 2-AG in the canine gut [309], today it is known that these host-derived endocannabinoid lipid hormones are found in various peripheral tissues (e.g., the intestine) and in the serum, and produced by certain immune cells [23,290,[309][310][311][312][313][314][315][316][317]. For instance, lipopolysaccharides induced the production of AEA in adipose tissue macrophages [318]. ...
... 2-AG was found to be present at 170 times higher concentrations than AEA in brain lysate [308]. While AEA was initially detected in the brain [135] and 2-AG in the canine gut [309], today it is known that these host-derived endocannabinoid lipid hormones are found in various peripheral tissues (e.g., the intestine) and in the serum, and produced by certain immune cells [23,290,[309][310][311][312][313][314][315][316][317]. For instance, lipopolysaccharides induced the production of AEA in adipose tissue macrophages [318]. ...
Article
Full-text available
Antibiotic resistance has become an increasing challenge in the treatment of various infectious diseases, especially those associated with biofilm formation on biotic and abiotic materials. There is an urgent need for new treatment protocols that can also target biofilm-embedded bacteria. Many secondary metabolites of plants possess anti-bacterial activities, and especially the phytocannabinoids of the Cannabis sativa L. varieties have reached a renaissance and attracted much attention for their anti-microbial and anti-biofilm activities at concentrations below the cytotoxic threshold on normal mammalian cells. Accordingly, many synthetic cannabinoids have been designed with the intention to increase the specificity and selectivity of the compounds. The structurally unrelated endocannabinoids have also been found to have anti-microbial and anti-biofilm activities. Recent data suggest for a mutual communication between the endocannabinoid system and the gut microbiota. The present review focuses on the anti-microbial activities of phytocannabinoids and endocannabinoids integrated with some selected issues of their many physiological and pharmacological activities.
... Other findings provide room for such an additional agonist. Pharmacological studies dealing with anandamide and 2-AG binding at CB2 reported rather low binding affinities at the µM range, more specifically, one order of magnitude lower than that of THC (Munro et al., 1993;Mechoulam et al., 1995), suggesting that there could be a more specific and potent endogenous ligand. Furthermore, physiological results from several research groups suggest that anandamide and 2-AG have opposing effects on CB2 signaling Gonsiorek et al., 2000). ...
... OGP(1-14) is physiologically present in the serum at nano-to micromolar concentrations, with most of it complexed to α2-macroglobulin (Greenberg et al., 1995;Gavish et al., 1997;Bab et al., 1999). Upon dissociation from this complex, it is proteolytically cleaved, thus generating its 5-amino-acid cellular activator OGP (Idris et al., 2008;Karsak et al., 2005;Mechoulam et al., 1995;Tam et al., 2008;Gonsiorek et al., 2000) referred to here as OGP (Bab et al., 1999). This pentapeptide targets a pertussis toxin-sensitive GPCR and consequently activates a Gi-protein -Erk1/2 -Mapkapk2 -CREB cascade (Miguel et al., 2005). ...
Article
Full-text available
The endocannabinoid system consists mainly of 2-arachidonoylglycerol and anandamide, as well as cannabinoid receptor type 1 (CB1) and type 2 (CB2). Based on previous studies, we hypothesized that a circulating peptide previously identified as Osteogenic Growth Peptide (OGP) maintains a bone-protective CB2 tone. We tested OGP activity in mouse models and cells, and in human osteoblasts. We show that the OGP effects on osteoblast proliferation, osteoclastogenesis, and macrophage inflammation in vitro , as well as rescue of ovariectomy-induced bone loss and prevention of ear edema in vivo are all abrogated by genetic or pharmacological ablation of CB2. We also demonstrate that OGP binds at CB2 and may act as both an agonist and positive allosteric modulator in the presence of other lipophilic agonists. In premenopausal women, OGP circulating levels significantly decline with age. In adult mice, exogenous administration of OGP completely prevented age-related bone loss. Our findings suggest that OGP attenuates age-related bone loss by maintaining a skeletal CB2 tone. Importantly, they also indicate the occurrence of an endogenous peptide that signals via CB2 receptor in health and disease.
... Just to give a few examples, he was the first to elucidate in 1964 the complete structure of THC [3]. Then, he identified many additional phytocannabinoids in 1965-1972 (reviewed in ref. [1]), and later on discovered also the endogenous counterparts of THC: anandamide in 1992 [4], and 2-arachidonoylglycerol in 1995 [5], the latter at the same time and independently of Sugiura and colleagues in Japan [6]. Then, Raphi identified arachidonoyl-serine, an endogenous vasodilator, in 2006, and oleoyl-serine, an endogenous regulator of bone mass, in 2010 (reviewed in refs [7,8]). ...
Article
Full-text available
During the last 60 years the relevance for human health and disease of cannabis (Cannabis sativa or Cannabis indica) ingredients, like the psychoactive compound Δ9-tetrahydrocannabinol (THC), cannabidiol, 120+ cannabinoids and 440+ non-cannabinoid compounds, has become apparent [...]
... In 1992, Devane et al. discovered the first endocannabinoid (eCB) N-arachidonoylethanolamine or anandamide (AEA) as the endogenous ligand of CBR in the pig brain (Devane et al., 1992) . Subsequently in 1995, the second eCB 2-arachidonoylglycerol (2-AG) was also discovered (Mechoulam et al., 1995). With the discovery of endocannabinoids, a great number of studies have investigated the physiological functions of the endocannabinoid system (ECS). ...
Article
Full-text available
Background: The endocannabinoid system (ECS) is involved in multiple physiological processes, including appetite regulation, pain perception, motor function development, and immune response regulation. Cannabinoids have been approved for the clinical treatment of nausea and vomiting caused by cytostatic therapy or cancer chemotherapy, loss of appetite in HIV/AIDS-associated cachexia, refractory spasms induced by multiple sclerosis, chronic pain, and urinary incontinence. Methods: Check out the research on ECS and bone diseases in the past 20 years. Results: Many studies have demonstrated that endocannabinoids (eCBs) and cannabinoid receptors (CBRs) are expressed in bone and synovial tissues, playing important roles in bone metabolism. Preclinical studies using cannabis-based therapies in animal models have shown that cannabinoids (CBs) can alleviate the development of osteoarthritis (OA), prevent osteoporosis (OP), reduce cancer-induced osteolytic destruction, and improve fracture healing, highlighting the therapeutic potential of CBs for human bone diseases. Conclusions: The present review summarizes various components of the ECS in bone diseases and their potential as a therapeutic target.
... Following the discovery of the CB1 and CB2 receptors, the endogenous cannabinoids (or endocannabinoids) anandamide [N-arachidonoylethanolamine (AEA)] and 2arachidonoylglycerol (2-AG) were isolated (Devane, et al., 1992;Mechoulam, et al., 1995;Sugiura, et al., 1995). These endocannabinoids are synthesized from the cell membrane lipids N-arachidonoyl phosphatidyl ethanol (NAPE) (for AEA) and phosphatidyl inositol bis-phosphate (PIP2) (for 2-AG). ...
Article
Full-text available
The medicinal use of Cannabis sativa L. can be traced back thousands of years to ancient China and Egypt. While marijuana has recently shown promise in managing chronic pain and nausea, scientific investigation of cannabis has been restricted due its classification as a schedule 1 controlled substance. A major breakthrough in understanding the pharmacology of cannabis came with the isolation and characterization of the phytocannabinoids trans -Δ ⁹ -tetrahydrocannabinol (Δ ⁹ -THC) and cannabidiol (CBD). This was followed by the cloning of the cannabinoid CB1 and CB2 receptors in the 1990s and the subsequent discovery of the endocannabinoid system. In addition to the major phytocannabinoids, Δ ⁹ -THC and CBD, cannabis produces over 120 other cannabinoids that are referred to as minor and/or rare cannabinoids. These cannabinoids are produced in smaller amounts in the plant and are derived along with Δ ⁹ -THC and CBD from the parent cannabinoid cannabigerolic acid (CBGA). While our current knowledge of minor cannabinoid pharmacology is incomplete, studies demonstrate that they act as agonists and antagonists at multiple targets including CB1 and CB2 receptors, transient receptor potential (TRP) channels, peroxisome proliferator-activated receptors (PPARs), serotonin 5-HT 1a receptors and others. The resulting activation of multiple cell signaling pathways, combined with their putative synergistic activity, provides a mechanistic basis for their therapeutic actions. Initial clinical reports suggest that these cannabinoids may have potential benefits in the treatment of neuropathic pain, neurodegenerative diseases, epilepsy, cancer and skin disorders. This review focuses on the molecular pharmacology of the minor cannabinoids and highlights some important therapeutic uses of the compounds.
... [40]. CB1 is expressed in all brain area, in fact, it is known as being the most abundant GPCR in the mammalian brain [41]. In most brain areas, CB1 is expressed in the presynaptic terminals of neurons of both glutamatergic acid and gamma aminobutyric acid (GABA) which has been observed to exhibit both homodimeric and heterodimeric structures [42]. ...
Article
Full-text available
Polypharmacology breaks up the classical paradigm of “one-drug, one target, one disease” electing multitarget compounds as potential therapeutic tools suitable for the treatment of complex diseases, such as metabolic syndrome, psychiatric or degenerative central nervous system (CNS) disorders, and cancer. These diseases often require a combination therapy which may result in positive but also negative synergistic effects. The endocannabinoid system (ECS) is emerging as a particularly attractive therapeutic target in CNS disorders and neurodegenerative diseases including Parkinson’s disease (PD), Alzheimer’s disease (AD), Huntington’s disease (HD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), stroke, traumatic brain injury (TBI), pain, and epilepsy. ECS is an organized neuromodulatory network, composed by endogenous cannabinoids, cannabinoid receptors type 1 and type 2 (CB1 and CB2), and the main catabolic enzymes involved in the endocannabinoid inactivation such as fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL). The multiple connections of the ECS with other signaling pathways in the CNS allows the consideration of the ECS as an optimal source of inspiration in the development of innovative polypharmacological compounds. In this review, we focused our attention on the reported polypharmacological examples in which FAAH and MAGL inhibitors are involved.
... 113 The second key ligand identified was 2-arachidonoylglycerol (2-AG). 114 Since the discovery of these two major compounds, the eCB family has been expanded and is no longer restricted to only eCBs with specific activity on CB 1 and CB 2 receptors. For example, some eCBs also interact with PPARα and PPARγ, as well as with other membrane receptors such as GPR55, or transient receptor potential vanilloid type-1 (TRPV1) (figure 4). ...
Article
Full-text available
The gut microbiota is now considered as one of the key elements contributing to the regulation of host health. Virtually all our body sites are colonised by microbes suggesting different types of crosstalk with our organs. Because of the development of molecular tools and techniques (ie, metagenomic, metabolomic, lipidomic, metatranscriptomic), the complex interactions occurring between the host and the different microorganisms are progressively being deciphered. Nowadays, gut microbiota deviations are linked with many diseases including obesity, type 2 diabetes, hepatic steatosis, intestinal bowel diseases (IBDs) and several types of cancer. Thus, suggesting that various pathways involved in immunity, energy, lipid and glucose metabolism are affected. In this review, specific attention is given to provide a critical evaluation of the current understanding in this field. Numerous molecular mechanisms explaining how gut bacteria might be causally linked with the protection or the onset of diseases are discussed. We examine well-established metabolites (ie, short-chain fatty acids, bile acids, trimethylamine N-oxide) and extend this to more recently identified molecular actors (ie, endocannabinoids, bioactive lipids, phenolic-derived compounds, advanced glycation end products and enterosynes) and their specific receptors such as peroxisome proliferator-activated receptor alpha (PPARα) and gamma (PPARγ), aryl hydrocarbon receptor (AhR), and G protein-coupled receptors (ie, GPR41, GPR43, GPR119, Takeda G protein-coupled receptor 5). Altogether, understanding the complexity and the molecular aspects linking gut microbes to health will help to set the basis for novel therapies that are already being developed.
... It also seems plausible that other eCBs receptors are involved, particularly type 3 CB (CB3), known as GPR55 [13], and the transient receptor potential vanilloid 1 (TRPV1) ion channel [14]. AEA binds both receptor subtypes, with higher selectivity for CB1 than for CB2 [15], whilst 2-AG activates both receptor subtypes as a full agonist [16]. AEA and 2-AG are synthesized from lipid precursors and subsequently released from postsynaptic neurons into the synaptic space [17]. ...
Article
Full-text available
The endocannabinoid system (ECS) influences many biological functions, and hence, its pharmacological modulation may be useful for several disorders, such as migraine. Preclinical studies have demonstrated that the ECS is involved in the modulation of trigeminal excitability. Additionally, clinical data have suggested that an endocannabinoid deficiency is associated with migraine. Given these data, phytocannabinoids, as well as synthetic cannabinoids, have been tried as migraine treatments. In this narrative review, the current clinical evidence of potential ECS involvement in migraine pathogenesis is summarized. Furthermore, studies exploring the clinical effects of phytocannabinoids and synthetic cannabinoids on migraine patients are reviewed.
... The endocannabinoid (eCB) system is a lipid-derived signaling apparatus composed of: (i) G protein-coupled cannabinoid receptors type 1 and type 2, CB1 and CB2; (ii) two main endogenous ligands of such receptors (the so-called endocannabinoids), derived from arachidonic acid, i.e., N-arachidonoyl-ethanolamine (AEA or anandamide) and 2arachidonoyl-glycerol (2-AG), the latter being first isolated from the canine gut [77]; and (iii) the anabolic and catabolic enzymes for the endocannabinoids [78]. AEA and 2-AG are biosynthesized "on demand" through the action of lipases that are stimulated by elevation of intracellular calcium or activation of G proteins [79]. ...
Article
Full-text available
There is growing evidence that perturbation of the gut microbiome, known as “dysbiosis”, is associated with the pathogenesis of human and veterinary diseases that are not restricted to the gastrointestinal tract. In this regard, recent studies have demonstrated that dysbiosis is linked to the pathogenesis of central neuroinflammatory disorders, supporting the existence of the so-called microbiome-gut-brain axis. The endocannabinoid system is a recently recognized lipid signaling system and termed endocannabinoidome monitoring a variety of body responses. Accumulating evidence demonstrates that a profound link exists between the gut microbiome and the endocannabinoidome, with mutual interactions controlling intestinal homeostasis, energy metabolism and neuroinflammatory responses during physiological conditions. In the present review, we summarize the latest data on the microbiome-endocannabinoidome mutual link in health and disease, focalizing the attention on gut dysbiosis and/or altered endocannabinoidome tone that may distort the bidirectional crosstalk between these two complex systems, thus leading to gastrointestinal and metabolic diseases (e.g., idiopathic inflammation, chronic enteropathies and obesity) as well as neuroinflammatory disorders (e.g., neuropathic pain and depression). We also briefly discuss the novel possible dietary interventions based not only on probiotics and/or prebiotics, but also, and most importantly, on endocannabinoid-like modulators (e.g., palmitoylethanolamide) for intestinal health and beyond.
... AEA is synthesized by the enzyme N-acyl phosphatidylethanolamine-specific phospholipase D (NAPE-PLD) and degraded by fatty acid amide hydrolase (FAAH). The second identified endocannabinoid was 2arachidonoylglycerol (2-AG) which also activates both CB 1 and CB 2 receptors (Mechoulam et al., 1995;Sugiura et al., 1995;Stella et al., 1997). In human serum, 2-AG is up to 100fold more abundant than AEA (Hillard et al., 2012). ...
Article
Full-text available
Microglia, the resident immune cells of the brain, can take on a range of pro-or anti-inflammatory phenotypes to maintain homeostasis. However, the sustained activation of pro-inflammatory microglia can lead to a state of chronic neuroinflammation characterized by high concentrations of neurotoxic soluble factors throughout the brain. In healthy brains, the inflammatory processes cease and microglia transition to an anti-inflammatory phenotype, but failure to halt the pro-inflammatory processes is a characteristic of many neurological disorders. The endocannabinoid system has been identified as a promising therapeutic target for chronic neuroinflammation as there is evidence that synthetic and endogenously produced cannabinoids temper the pro-inflammatory response of microglia and may encourage a switch to an anti-inflammatory phenotype. Activation of cannabinoid type 2 (CB 2) receptors has been proposed as the mechanism of action responsible for these effects. The abundance of components of the endocannabinoid system in microglia also change dynamically in response to several brain pathologies. This can impact the ability of microglia to synthesize and degrade endocannabinoids or react to endogenous and exogenous cannabinoids. Cannabinoid receptors also participate in the formation of receptor heteromers which influences their function specifically in cells that express both receptors, such as microglia. This creates opportunities for drug-drug interactions between CB 2 receptor-targeted therapies and other classes of drugs. In this article, we review the roles of pro-and anti-inflammatory microglia in the development and resolution of neuroinflammation. We also discuss the fluctuations observed in the components of the endocannabinoid in microglia and examine the potential of CB 2 receptors as a therapeutic target in this context.
... 19,20,28,32 The discovery of these specific CB receptors led to the isolation of their endogenously formed ligands, including two lipid-derived principal eCBs, arachidonoylethanolamide (anandamide [AEA]) and 2-arachidonoylglycerol (2-AG). [33][34][35][36] AEA is a partial agonist with high affinity for CB 1 , whereas 2-AG is a full agonist with a lower affinity for CB 1 . 37 Other GPCRs and other targets also recognize CBs and related endogenous lipids; however, their role is less well understood. ...
Article
Purpose: A growing body of evidence has implicated the endocannabinoid (eCB) system in the acute, chronic, and withdrawal effects of alcohol/ethanol on synaptic function. These eCB-mediated synaptic effects may contribute to the development of alcohol use disorder (AUD). Alcohol exposure causes neurobiological alterations similar to those elicited by chronic cannabinoid (CB) exposure. Like alcohol, cannabinoids alter many central processes, such as cognition, locomotion, synaptic transmission, and neurotransmitter release. There is a strong need to elucidate the effects of ethanol on the eCB system in different brain regions to understand the role of eCB signaling in AUD. Search methods: For the scope of this review, preclinical studies were identified through queries of the PubMed database. Search results: This search yielded 459 articles. Clinical studies and papers irrelevant to the topic of this review were excluded. Discussion and conclusions: The endocannabinoid system includes, but is not limited to, cannabinoid receptors 1 (CB1), among the most abundantly expressed neuronal receptors in the brain; cannabinoid receptors 2 (CB2); and endogenously formed CB1 ligands, including arachidonoylethanolamide (AEA; anandamide), and 2-arachidonoylglycerol (2-AG). The development of specific CB1 agonists, such as WIN 55,212-2 (WIN), and antagonists, such as SR 141716A (rimonabant), provide powerful pharmacological tools for eCB research. Alcohol exposure has brain region-specific effects on the eCB system, including altering the synthesis of endocannabinoids (e.g., AEA, 2-AG), the synthesis of their precursors, and the density and coupling efficacy of CB1. These alcohol-induced alterations of the eCB system have subsequent effects on synaptic function including neuronal excitability and postsynaptic conductance. This review will provide a comprehensive evaluation of the current literature on the synaptic interactions of alcohol exposure and eCB signaling systems, with an emphasis on molecular and physiological synaptic effects of alcohol on the eCB system. A limited volume of studies has focused on the underlying interactions of alcohol and the eCB system at the synaptic level in the brain. Thus, the data on synaptic interactions are sparse, and future research addressing these interactions is much needed.
... Type 1 cannabinoid receptors (CB1) [154] and type 2 cannabinoid receptors (CB) [155] are eukaryote-specific, class A, G protein-coupled membrane receptors (GPCRs) that are widely distributed and highly expressed throughout mammalian tissues. Cannabinoid (CB) receptors are activated by the endogenous cannabinoids anandamide (AEA) [156] and 2-arachidonoylglycerol (2-AG) [157,158] to modulate neuronal excitability, synaptic neurotransmitter release throughout the CNS, and inflammatory processes [159][160][161]. ...
Article
Full-text available
Despite current therapeutic strategies for immunomodulation and relief of symptoms in multiple sclerosis (MS), remyelination falls short due to dynamic neuropathologic deterioration and relapses, leading to accrual of disability and associated patient dissatisfaction. The potential of cannabinoids includes add-on immunosuppressive, analgesic, neuroprotective, and remyelinative effects. This study evaluates the efficacy of medical marijuana in MS and its experimental animal models. A systematic review was conducted by a literature search through PubMed, ProQuest, and EBSCO electronic databases for studies reported since 2007 on the use of cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) in MS and in experimental autoimmune encephalomyelitis (EAE), Theiler’s murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD), and toxin-induced demyelination models. Study selection and data extraction were performed by 3 reviewers, and 28 studies were selected for inclusion. The certainty of evidence was appraised using the Cochrane GRADE approach. In clinical studies, there was low- and moderate-quality evidence that treatment with ~1:1 CBD/THC mixtures as a nabiximols (Sativex®) oromucosal spray reduced numerical rating scale (NRS) scores for spasticity, pain, and sleep disturbance, diminished bladder overactivity, and decreased proinflammatory cytokine and transcription factor expression levels. Preclinical studies demonstrated decreases in disease severity, hindlimb stiffness, motor function, neuroinflammation, and demyelination. Other experimental systems showed the capacity of cannabinoids to promote remyelination in vitro and by electron microscopy. Modest short-term benefits were realized in MS responders to adjunctive therapy with CBD/THC mixtures. Future studies are recommended to investigate the cellular and molecular mechanisms of cannabinoid effects on MS lesions and to evaluate whether medical marijuana can accelerate remyelination and retard the accrual of disability over the long term.
... Endocannabinoids are endogenous lipid-signaling molecules that mimic the pharmacological action of the principal psychoactive component of marijuana, delta-9-tetrahydrocannabinol (Δ 9 -THC) (Gaoni and Mechoulam, 1964). Anandamide (AEA) (Devane et al., 1992) and 2-arachidonoyl glycerol (2-AG) (Mechoulam et al., 1995) are the two best-studied endocannabinoids. Endocannabinoids possess cannabimimetic properties because they bind and activate cannabinoid receptor 1 (CB 1 ) (Devane et al., 1988) and/or cannabinoid receptor 2 (CB 2 ) (Munro et al., 1993). ...
Article
Full-text available
Cannabinoid-based therapies are increasingly being used by cancer patients to treat chemotherapy-induced nausea and vomiting. Recently, cannabinoids have gained increased attention for their effects on cancer growth. Indeed, the effect of CB2 (JWH-015, JWH-133) agonists on breast cancer models have shown to reduce the size of breast cancer tumors. However, these studies assessing breast cancer progression were using CB2 agonist administered early into the cancer progression therefore assessing their effects on already established tumors is a critical need. In our study, we evaluate tumor growth using an ectopic xenograft ovarian (SKOV-3 and OVCAR-5) cancer model. The impact of chronic (30 days) administration of CB2 (JWH-133) agonist will be evaluated and started on 30 days of ectopic ovarian tumors. We will then evaluate and determine the mechanisms involved in ovarian cancer tumor growth by measuring levels of anandamide and 2-arachidonoyl glycerol as well as protein levels of CB1, CB2, ERα, ERβ, GPER, TNFα, IL-1β and IL-6 in ovarian and tumor tissues. Our results demonstrate a significant increase in ectopic ovarian tumor growth following chronic administration of JWH-133. Ovarian cancer tumor tissues chronically (30 days) treated with JWH-133 in comparison to vehicle treated groups showed an increase in endocannabinoid (AEA and 2-AG) and protein (CB2 and TNFα) levels with a decrease in GPER protein levels. Interestingly, our study emphasizes the importance of studying the impact of cannabinoid compounds on already established tumors to improve our understanding of cannabinoid-based therapies and, therefore better address clinical needs in cancer patients.
... The G i/o protein-coupled receptors for 9 -THC, namely cannabinoid type 1 (CB 1 ) and type 2 (CB 2 ), were cloned in 1990 (Matsuda et al., 1990) and 1993 (Munro et al., 1993), respectively. The endogenous ligands for the cannabinoid receptors, namely, N-arachidonoyl ethanolamine (anandamide, AEA) and 2arachidonoyl glycerol (2-AG), were identified in 1992 (Devane et al., 1992) and 1995 (Mechoulam et al., 1995;Sugiura et al., 1995), respectively. It has now been suggested that there are other receptors, besides CB 1 and CB 2 , for these endocannabinoids, including G protein-coupled receptor 55 (GPR55) (Baker et al., 2006) and transient receptor potential vanilloid 1 (TRPV1) (Smart et al., 2000). ...
Article
Full-text available
Research on endocannabinoid signaling has greatly advanced our understanding of how the excitability of neural circuits is controlled in health and disease. In general, endocannabinoid signaling at excitatory synapses suppresses excitability by inhibiting glutamate release, while that at inhibitory synapses promotes excitability by inhibiting GABA release, although there are some exceptions in genetically epileptic animal models. In the epileptic brain, the physiological distributions of endocannabinoid signaling molecules are disrupted during epileptogenesis, contributing to the occurrence of spontaneous seizures. However, it is still unknown how endocannabinoid signaling changes during seizures and how the redistribution of endocannabinoid signaling molecules proceeds during epileptogenesis. Recent development of cannabinoid sensors has enabled us to investigate endocannabinoid signaling in much greater spatial and temporal details than before. Application of cannabinoid sensors to epilepsy research has elucidated activity-dependent changes in endocannabinoid signaling during seizures. Furthermore, recent endocannabinoid research has paved the way for the clinical use of cannabidiol for the treatment of refractory epilepsy, such as Dravet syndrome, Lennox-Gastaut syndrome and tuberous sclerosis complex. Cannabidiol significantly reduces seizures and is considered to have comparable tolerability to conventional antiepileptic drugs. In this article, we introduce recent advances in research on the roles of endocannabinoid signaling in epileptic seizures and discuss future directions.
... The ECS is also a potent modulator of inflammatory responses and immune function in mammals. For example, AEA and 2-AG have both anti-and pro-inflammatory functions [17][18][19]. The cannabinoid-2 (CB2) receptor, expressed by various cells of the immune system, can also modulate the release of cytokines and appears to have a critical role in immune regulation and function [20]. ...
Article
Full-text available
Environmental heat load (HL) adversely affects the performance of dairy cows. The endocannabinoid system (ECS) regulates metabolism and the stress response, thus we hypothesized that HL may affect the ECS of dairy cows. Our objective was to determine the levels of endocannabinoids (eCBs) and gene and protein expressions of the ECS components in adipose tissue (AT) and plasma of early postpartum (PP) and late-lactation cows. In addition, we examined eCBs in milk, and studied the interaction of eCBs with bovine cannabinoids receptors CB1 and CB2. In the first experiment, plasma and AT were sampled from cows calving during summer (S, n = 9) or winter (W, n = 9). Dry matter intake (DMI) and energy balance (EB) were lower in S vs. W, and relative gene expressions of transient-receptor-potential-cation-channel-subfamily-V-member-1 (TRPV1), the cannabinoid receptors CNR1 (CB1) and CNR2 (CB2), and monoglyceride lipase (MGLL) were decreased in AT of S compared to W. Protein abundance of peroxisome proliferator-activated-receptor-alpha (PPAR-α) was decreased, while tumor-necrosis factor-α (TNF-α) was increased in AT of S vs. W. Other components of the ECS were not different between S and W calving cows. To study whether the degree of HL may affect the ECS, we performed a second experiment with 24 late-lactation cows that were either cooled (CL) or not cooled (heat-stressed; HS) during summer. DMI was lower in HS vs. CL, AT protein abundance of PPAR-α was lower, and TRPV1 tended to be lower in HS vs. CL, but other components of the ECS were not different between groups. Milk levels of 2-arachidonoylglycerol (2-AG) tended to increase in HS vs. CL. Additionally, modeling of the bovine cannabinoid receptors demonstrated their binding to anandamide and 2-AG. Environmental HL, possibly via lower intake, is associated with limited alterations in ECS components in AT of dairy cows.
... Initially isolated from the porcine brain, anandamide is a partial agonist with CBR-1 and CBR-2. Next, 2-AG was isolated from canine intestines as a full agonist with CBR-1 and CBR-2 [47][48][49]. Further putative ECs have been discovered more recently. ...
Article
Full-text available
Cannabis, as a natural medicinal remedy, has long been used for palliative treatment to alleviate the side effects caused by diseases. Cannabis-based products isolated from plant extracts exhibit potent immunoregulatory properties, reducing chronic inflammatory processes and providing much needed pain relief. They are a proven effective solution for treatment-based side effects, easing the resulting symptoms of the disease. However, we discuss the fact that cannabis use may promote the progression of a range of malignancies, interfere with anti-cancer immunotherapy, or increase susceptibility to viral infections and transmission. Most cannabis preparations or isolated active components cause an overall potent immunosuppressive impact among users, posing a considerable hazard to patients with suppressed or compromised immune systems. In this review, current knowledge and perceptions of cannabis or cannabinoids and their impact on various immune-system components will be discussed as the “two sides of the same coin” or “double-edged sword”, referring to something that can have both favorable and unfavorable consequences. We propose that much is still unknown about adverse reactions to its use, and its integration with medical treatment should be conducted cautiously with consideration of the individual patient, effector cells, microenvironment, and the immune system.
... The endocannabinoid system includes the endocannabinoid receptors, endogenous agonists and enzymes that synthesise and degrade endocannabinoids. N-arachidonoylethanolamine (anandamide, AEA) and 2-arachidonoylglycerol (2-AG) were the first arachidonic acid derivatives described as endogenous agonists at cannabinoid receptors [24,25]. Later, further lipids were identified as endocannabinoids, such as N-arachidonoyldopamine (NADA) [26]; 2arachidonoylglycerol ether (2-AGE, noladin ether), a structural ether analogue of 2-AG with higher stability than 2-AG [27]; and O-arachidonoylethanolamine (virodhamine), an ester derivative of arachidonic acid and ethanolamine [28]. ...
Article
Full-text available
Drugs targeting the endocannabinoid system are of interest as potential systemic chemotherapeutic treatments and for palliative care in cancer. In this context, cannabinoid compounds have been successfully tested as a systemic therapeutic option in preclinical models over the past decades. Recent findings have suggested an essential function of the endocannabinoid system in the homeostasis of various skin functions and indicated that cannabinoids could also be considered for the treatment and prophylaxis of tumour diseases of the skin. Cannabinoids have been shown to exert their anticarcinogenic effects at different levels of skin cancer progression, such as inhibition of tumour growth, proliferation, invasion and angiogenesis, as well as inducing apoptosis and autophagy. This review provides an insight into the current literature on cannabinoid compounds as potential pharmaceuticals for the treatment of melanoma and squamous cell carcinoma.
... Since CBs were discovered, it has been speculated that endogenous ligands might exist. In fact, in 1992, the endocannabinoid AEA was isolated from the pig brain [34], and three years later, 2-AG was found in the canine gut [35] and rat brain ( Figure 1) [36]. AEA is synthetized on demand from membrane phospholipids through the action of the enzyme N-acylphosphatidylethanolamine-phospholipase D (NAPE-PLD) [5,21,37]. ...
Article
Full-text available
Although cannabinoids have been used for centuries for diverse pathological conditions, recently, their clinical interest and application have emerged due to their diverse pharmacological properties. Indeed, it is well established that cannabinoids exert important actions on multiple sclerosis, epilepsy and pain relief. Regarding cancer, cannabinoids were first introduced to manage chemotherapy-related side effects, though several studies demonstrated that they could modulate the proliferation and death of different cancer cells, as well as angiogenesis, making them attractive agents for cancer treatment. In relation to breast cancer, it has been suggested that estrogen receptor-negative (ER−) cells are more sensitive to cannabinoids than estrogen receptor-positive (ER+) cells. In fact, most of the studies regarding their effects on breast tumors have been conducted on triple-negative breast cancer (TNBC). Nonetheless, the number of studies on human epidermal growth factor receptor 2-positive (HER2+) and ER+ breast tumors has been rising in recent years. However, besides the optimistic results obtained thus far, there is still a long way to go to fully understand the role of these molecules. This review intends to help clarify the clinical potential of cannabinoids for each breast cancer subtype.
... Imbalances in the retinal eCB system levels may cause or exacerbate pathological disorders such as glaucoma, macular degeneration, diabetic retinopathy, and retinitis pigmentosa [26][27][28][29]. The endogenous ligands of CB1R (anandamide or AEA; [30], and 2-arachidonoylglycerol or 2-AG; [31,32]) are produced "on demand" and act retrogradely by binding to cannabinoid receptors [33]. The eCBs, among other bioactive lipids such as some simple esters and amides with long unsaturated acyl chains, are majorly degraded by the fatty acid amide hydrolase (FAAH) enzyme [34,35], and as such, inhibition of FAAH leads to an accumulation of some eCBs. ...
Article
Full-text available
Recent studies using full-field electroretinography (ffERG) that triggers a non-specific mass response generated by several retinal sources have attributed an important role for cannabinoid receptors in mediating vision in primates. Specific cone-mediated responses evoked through the photopic flicker ERG appear to be a better way to validate the assumption that endogenous cannabinoids modulate the cone pathway, since FAAH is mainly expressed in the vervet monkey cone photoreceptors. The aim of this study is two-fold: (1) to use the photopic flicker ERG to target the cone pathway specifically, and (2) use URB597 as a selective inhibitor of the endocannabinoid degrading enzyme Fatty Acid Amide Hydrolase (FAAH) to enhance the levels of fatty acid amides, particularly anandamide. We recorded ERGs under four different flicker frequencies (15, 20, 25, and 30 Hz) in light-adapted conditions after intravitreal injections of URB597. Our results show that intravitreal injections of URB597, compared to the vehicle DMSO, increased significantly ffERG amplitudes at 30 Hz, a frequency that solely recruits cone activity. However, at 15 Hz, a frequency that activates both rods and cones, no significant difference was found in the ERG response amplitude. Additionally, we found no differences in implicit times after URB597 injections compared to DMSO vehicle. These results support the role of molecules degraded by FAAH in cone-mediated vision in non-human primates.
... 2-Arachidonoyl glycerol (2-AG) was isolated from canine intestine using methanol extraction, gas chromatography and nuclear magnetic resonance [69]. There are three identified pathways for the synthesis of 2-AG, while the first appears to be the main pathway in central nervous system: after the stimulation of receptors such as M1 or M3 muscarinic, phospholipase C-β (PLCβ) hydrolyzed an arachidonoyl-containing phosphatidylinositol 4,5-bisphosphate (PIP2), obtaining dyacilglycerol; then another hydrolysis occurs due to the action of diacylglycerol lipase (DAGL). ...
Article
Full-text available
The concept of neurons as irreplaceable cells does not hold true today. Experiments and evidence of neurogenesis, also, in the adult brain give hope that some compounds or drugs can enhance this process, helping to reverse the outcomes of diseases or traumas that once were thought to be everlasting. Cannabinoids, both from natural and artificial origins, already proved to have several beneficial effects (e.g., anti-inflammatory, anti-oxidants and analgesic action), but also capacity to increase neuronal population, by replacing the cells that were lost and/or regenerate a damaged nerve cell. Neurogenesis is a process which is not highly represented in literature as neuroprotection, though it is as important as prevention of nervous system damage, because it can represent a possible solution when neuronal death is already present, such as in neurodegenerative diseases. The aim of this review is to resume the experimental evidence of phyto- and synthetic cannabinoids effects on neurogenesis, both in vitro and in vivo, in order to elucidate if they possess also neurogenetic and neurorepairing properties.
... The body produces endogenous ligands to these receptors, with the first being identified in 1992: N-arachidonoylethanolamide, named anandamide for short after the Sanskrit word ananda, meaning bliss [9]. Some years later, in 1995, a second endogenous cannabinoid was identified: 2-arachidonoylglycerol (2-AG) [10][11][12][13][14][15][16]. These endogenous cannabinoid ligands are produced immediately before excitatory release from fatty compounds in the cell membrane of neuronal cells and are released mostly from the cell body and dendrites, where they exert their effects on presynaptic neurons [14]. ...
Article
Full-text available
Cannabis use can be traced back to several centuries before the Common Era, when it was used for industrial, medicinal and recreational purposes. More recently, over 100 different cannabinoid compounds have been identified, one of which is cannabidiol (CBD), a compound widely used for anti-inflammatory and anxiolytic treatment. The literature surrounding the cognitive effects of CBD is limited, with most studies focusing on the effects of other cannabinoids on cognition. To expand this literature, this study investigated whether CBD causes significant differences to working memory (WM) functioning, as measured by the N-back task. It was hypothesised that CBD does not cause statistically significant differences to WM. In all, 54 participants, 33 females and 21 males, were recruited, with a mean age of 32.63 years. Of these 54 participants, 26 reported using CBD and no other cannabinoids, while 28 reported not using any cannabinoid. The participants were instructed to answer a short online survey to gather basic demographic data and to complete an online N-back task to measure WM. For the computerised N-back task, the participants completed a practice and three test blocks, where they were instructed to respond to whether a series of letter stimuli were presented one trial back (1-back), two trials back (2-back) or three trials back (3-back). Multivariate analysis of covariance yielded no statistically significant difference on either response time or response accuracy data between groups after controlling for how long the participants use CBD and for what reason they use CBD. These results support our hypothesis that CBD does not cause significant changes to WM functioning. Further research is greatly needed to investigate the long-term effects of CBD use on WM and on general cognitive functioning.
... Following the discovery of the receptors, their endogenous lipid ligands were identified. The first two and best-studied are N-arachidonoylethanolamine (anandamide) (Devane et al., 1992) and 2-arachidonoylglycerol (2-AG) (Mechoulam et al., 1995). These eCBs and their specific receptors, CB1 and CB2, form the classical endocannabinoid system (eCBS) (De Petrocellis and Di Marzo, 2009;Lu and Mackie, 2016), a ubiquitous neuromodulatory signaling system that has widespread functions in the brain and throughout the body. ...
Article
Full-text available
Medical Cannabis and its major cannabinoids (−)-trans-Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are gaining momentum for various medical purposes as their therapeutic qualities are becoming better established. However, studies regarding their efficacy are oftentimes inconclusive. This is chiefly because Cannabis is a versatile plant rather than a single drug and its effects do not depend only on the amount of THC and CBD. Hundreds of Cannabis cultivars and hybrids exist worldwide, each with a unique and distinct chemical profile. Most studies focus on THC and CBD, but these are just two of over 140 phytocannabinoids found in the plant in addition to a milieu of terpenoids, flavonoids and other compounds with potential therapeutic activities. Different plants contain a very different array of these metabolites in varying relative ratios, and it is the interplay between these molecules from the plant and the endocannabinoid system in the body that determines the ultimate therapeutic response and associated adverse effects. Here, we discuss how phytocannabinoid profiles differ between plants depending on the chemovar types, review the major factors that affect secondary metabolite accumulation in the plant including the genotype, growth conditions, processing, storage and the delivery route; and highlight how these factors make Cannabis treatment highly complex.
... eCBs are agonists of CB1r and CB2r that are not accumulated in secretory vesicles but rather synthesized under tonic or phasic (on demand) modes, and released to the extracellular space following physiological and pathological stimuli [32]. The two main eCBs are derivatives of polyunsaturated fatty acids, N-arachidonoylethanolamine (anandamide, AEA) [33] and 2-arachidonoylglycerol (2-AG), being the most abundant eCBs in the brain [34]. ...
Article
Full-text available
The pharmacological modulation of the cannabinoid receptor 2 (CB2r) has emerged as a promising potential therapeutic option in addiction. The purpose of this review was to determine the functional involvement of CB2r in the effects produced by drugs of abuse at the central nervous system (CNS) level by assessing evidence from preclinical and clinical studies. In rodents, several reports suggest the functional involvement of CB2r in the effects produced by drugs of abuse such as alcohol, cocaine, or nicotine. In addition, the discovery of CB2r in brain areas that are part of the reward system supports the relevance of CB2r in the field of addiction. Interestingly, animal studies support that the CB2r regulates anxiety and depression behavioral traits. Due to its frequent comorbidity with neuropsychiatric disorders, these pharmacological actions may be of great interest in managing SUD. Preliminary clinical trials are focused on exploring the therapeutic potential of modulating CB2r in treating addictive disorders. These promising results support the development of new pharmacological tools regulating the CB2r that may help to increase the therapeutic success in the management of SUD.
... Moreover, blocking CB1 receptors in mice in the first 24 h of life inhibited the suckling of milk [99]. Added to the best known and first discovered ECS ligands should be included anandamide (AEA) and 2-arachidoyl glycerol (2-AG) [100,101]. Both endocannabinoids are formed "ondemand" [102]. ...
Article
Full-text available
Neoplastic diseases in children are the second most frequent cause of death among the young. It is estimated that 400,000 children worldwide will be diagnosed with cancer each year. The nutritional status at diagnosis is a prognostic indicator and influences the treatment tolerance. Both malnutrition and obesity increase the risk of mortality and complications during treatment. It is necessary to constantly search for new factors that impair the nutritional status. The endocannabinoid system (ECS) is a signaling system whose best-known function is regulating energy balance and food intake, but it also plays a role in pain control, embryogenesis, neurogenesis, learning, and the regulation of lipid and glucose metabolism. Its action is multidirectional, and its role is being discovered in an increasing number of diseases. In adults, cannabinoids have been shown to have anti-cancer properties against breast and pancreatic cancer, melanoma, lymphoma, and brain tumors. Data on the importance of both the endocannabinoid system and synthetic cannabinoids are lacking in children with cancer. This review highlights the role of nutritional status in the oncological treatment process, and describes the role of ECS and gastrointestinal peptides in regulating appetite. We also point to the need for research to evaluate the role of the endocannabinoid system in children with cancer, together with a prospective assessment of nutritional status during oncological treatment.
... Interestingly, CB1 receptor polymorphism has been linked to a reduced prevalence of depression in PD patients but not in control subjects [25]. We have shown that the MAGL inhibitor JZL184 produces anxiolytic and antidepressant-like behavioral effects in a chronic stress model of depression, and that these effects are mediated by the activation of CB1 receptors [26,27]. However, the usage of CB1 agonists may lead to substance abuse and dependence, including tolerance and withdrawal [28], which might limit their therapeutic potential. ...
Article
Full-text available
In addition to motor dysfunction, patients with Parkinson’s disease (PD) are often affected by neuropsychiatric disorders, such as anxiety and depression. In animal models, activation of the endocannabinoid (eCB) system produces anxiolytic and antidepressant-like behavioral effects. CB2 agonists have demonstrated neuroprotective effects against neurotoxin-induced dopamine neuron loss and deficits in motor function. However, it remains unknown whether CB2 agonism ameliorates anxiogenic- and depressive-like behaviors in PD models. Here, we report that the selective CB2 agonist GW842166x exerted neuroprotective effects against 6-hydroxydopamine (6-OHDA)-induced loss of dopaminergic terminals and dopamine release in the striatum, which were blocked by the CB2 antagonist AM630. We found that 6-OHDA-treated mice exhibited anxiogenic- and depressive-like behaviors in the open-field, sucrose preference, novelty-suppressed feeding, marble burying, and forced swim tests but did not show significant changes in the elevated plus-maze and light–dark box test. GW842166x treatments ameliorated 6-OHDA-induced anxiogenic- and depressive-like behaviors, but the effects were blocked by CB2 antagonism, suggesting a CB2-dependent mechanism. These results suggest that the CB2 agonist GW842166x not only reduces 6-OHDA-induced motor function deficits but also anxiogenic- and depressive-like behaviors in 6-OHDA mouse models of PD.
... The N-arachidonoylethanolamine, also called anandamide (AEA), was isolated in 1992 from the pig brain (Devane et al., 1992). A few years later, 2-arachidonyl glycerol (2-AG) was found in canine intestines (Mechoulam et al., 1995). Presently, novel molecules such as 2-arachidonyl glyceryl ether (2-AGE), virodhamine, N-arachidonoyl-dopamine, oleamide (OA), and oleoylethanolamine (OEA) are non-canonical eCBs (Iannotti et al., 2016;Cristino et al., 2020). ...
Article
Full-text available
Epilepsy is a neurological disorder with a high prevalence worldwide. Several studies carried out during the last decades indicate that the administration of cannabinoids as well as the activation of the endocannabinoid system (ECS) represent a therapeutic strategy to control epilepsy. However, there are controversial studies indicating that activation of ECS results in cell damage, inflammation and neurotoxicity, conditions that facilitate the seizure activity. The present review is focused to present findings supporting this issue. According to the current discrepancies, it is relevant to elucidate the different effects induced by the activation of ECS and determine the conditions under which it facilitates the seizure activity.
... AEA was the first endogenous ligand found in pig brain after the discovery of these receptors [22]. Later, another endogenous cannabis molecule known as 2AG was identified [23,24]. These two forms of endogenous cannabinoid-like structures were derivatives of arachidonic acid, while 2AG is the most prevalent endocannabinoid in the human brain. ...
Article
Full-text available
Phytocannabinoids are isoprenylated resorcinyl polyketides produced mostly in glandular trichomes of Cannabis sativa L. These discoveries led to the identification of cannabinoid receptors, which modulate psychotropic and pharmacological reactions and are found primarily in the human central nervous system. As a result of the biogenetic process, aliphatic ketide phytocannabinoids are exclusively found in the cannabis species and have a limited natural distribution, whereas phenethyl-type phytocannabinoids are present in higher plants, liverworts, and fungi. The development of cannabinomics has uncovered evidence of new sources containing various phytocannabinoid derivatives. Phytocannabinoids have been isolated as artifacts from their carboxylated forms (pre-cannabinoids or acidic cannabinoids) from plant sources. In this review, the overview of the phytocannabinoid biosynthesis is presented. Different non-cannabis plant sources are described either from those belonging to the angiosperm species and bryophytes, together with their metabolomic structures. Lastly, we discuss the legal framework for the ingestion of these biological materials which currently receive the attention as a legal high.
... The main endogenous ligands or endocannabinoids (eCBs) are 2-arachidonoylglycerol (2-AG) (Mechoulam et al., 1995;Sugiura et al., 1995) and N-arachidonoylethanolamine or anandamide (AEA) (Devane et al., 1992). Both eCBs are synthesized "on demand" from membrane lipid precursors. ...
Article
Full-text available
Stroke is the second leading cause of death worldwide following coronary heart disease. Despite significant efforts to find effective treatments to reduce neurological damage, many patients suffer from sequelae that impair their quality of life. For this reason, the search for new therapeutic options for the treatment of these patients is a priority. Glial cells, including microglia, astrocytes and oligodendrocytes, participate in crucial processes that allow the correct functioning of the neural tissue, being actively involved in the pathophysiological mechanisms of ischemic stroke. Although the exact mechanisms by which glial cells contribute in the pathophysiological context of stroke are not yet completely understood, they have emerged as potentially therapeutic targets to improve brain recovery. The endocannabinoid system has interesting immunomodulatory and protective effects in glial cells, and the pharmacological modulation of this signaling pathway has revealed potential neuroprotective effects in different neurological diseases. Therefore, here we recapitulate current findings on the potential promising contribution of the endocannabinoid system pharmacological manipulation in glial cells for the treatment of ischemic stroke.
Article
The endocannabinoid system (ECS) is a widespread cell signaling network that maintains homeostasis in response to endogenous and exogenous stressors. This has made the ECS an attractive therapeutic target for various disease states. The ECS is a well-known target of exogenous phytocannabinoids derived from cannabis plants, the most well characterized being Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD). However, the therapeutic efficacy of cannabis products comes with a risk of toxicity and high abuse potential due to the psychoactivity of THC. CBD, on the other hand, is reported to have beneficial medicinal properties including analgesic, neuroprotective, anxiolytic, anticonvulsant, and antipsychotic activities, while apparently lacking the toxicity of THC. Nevertheless, not only is the currently available scientific data concerning CBD’s efficacy insufficient, there is also ambiguity surrounding its regulatory status and safety in humans that brings inherent risks to manufacturers. There is a demand for alternative compounds combining similar effects with a robust safety profile and regulatory approval. Palmitoylethanolamide (PEA) is an endocannabinoid-like lipid mediator, primarily known for its anti-inflammatory, analgesic and neuroprotective properties. It appears to have a multi-modal mechanism of action, by primarily activating the nuclear receptor PPAR-α while also potentially working through the ECS, thus targeting similar pathways as CBD. With proven efficacy in several therapeutic areas, its safety and tolerability profile and the development of formulations that maximize its bioavailability, PEA is a promising alternative to CBD.
Chapter
The endocannabinoid system (ECS) was discovered in the early 1990s and is one of the most important neuroregulatory systems in the body. The ECS is responsible for homeostasis of most systems in the body. At a simplistic level, it is composed of endogenous ligands called endocannabinoids, cannabinoid receptors (CB1 and CB2 receptors), and enzymes that synthesize and degrade them. However, the ECS is actually more complex than this and there are other receptors and endocannabinoid-like substances involved in the ‘extended ECS’. CB1 receptors are particularly concentrated in the central nervous system and CB2 receptors are particularly concentrated in cells and tissues/organs of the immune system. However, cannabinoid receptors are also widely distributed throughout the body. In the nervous system, the classical understanding is that endocannabinoids are synthesized on demand in postsynaptic neurons and act as retrograde messengers, binding with cannabinoid receptors on presynaptic neurons to reduce neurotransmitter release from the presynaptic neuron. It is now known that there are also intracellular reservoirs and transporters of endocannabinoids. The ECS is critically involved in brain development, from the fetus through to adulthood. Dysfunction including deficiency of the ECS has been associated with a range of pathological disorders, including mental health conditions. The ECS plays a key role in the regulation of our mind and emotions and our reaction to stress. It is involved with the corticolimbic system and the HPA axis, both of which are key systems involved in regulation of stress and emotions. This chapter gives an overview of the ECS, as an understanding is necessary to later understand how medicinal cannabis may work in alleviating mental health disorders.
Article
Full-text available
Endocannabinoids are a group of endogenous mediators derived from membrane lipids, which are implicated in a wide variety of physiological functions such as blood pressure regulation, immunity, pain, memory, reward, perception, reproduction, and sleep. N-Arachidonoylethanolamine (anandamide; AEA) and 2-arachidonoylglycerol (2-AG) represent two major endocannabinoids in the human body and they exert many of their cellular and organ system effects by activating the Gi/o protein-coupled, cannabinoid type 1 (CB1) and type 2 (CB2) receptors. However, not all effects of cannabinoids are ascribable to their interaction with CB1 and CB2 receptors; indeed, macromolecules like other types of receptors, ion channels, transcription factors, enzymes, transporters, and cellular structure have been suggested to mediate the functional effects of cannabinoids. Among the proposed molecular targets of endocannabinoids, potassium channels constitute an intriguing group, because these channels not only are crucial in shaping action potentials and controlling the membrane potential and cell excitability, thereby regulating a wide array of physiological processes, but also serve as potential therapeutic targets for the treatment of cancer and metabolic, neurological and cardiovascular disorders. This review sought to survey evidence pertaining to the CB1 and CB2 receptor-independent actions of endocannabinoids on ion channels, with an emphasis on AEA and potassium channels. To better understand the functional roles as well as potential medicinal uses of cannabinoids in human health and disease, further mechanistic studies to delineate interactions between various types of cannabinoids and ion channels, including members in the potassium channel superfamily, are warranted.
Chapter
inner ear immunology in vestibular migraine and meniere disease, difrential proinflammatory profile
Article
Full-text available
The field of cannabinoid research has been receiving ever-growing interest. Ongoing debates worldwide about the legislation of medical cannabis further motivates research into cannabinoid function within the central nervous system (CNS). To date, two well-characterized cannabinoid receptors exist. While most research has investigated Cb 1 receptors (Cb 1 Rs), Cb 2 receptors (Cb 2 Rs) in the brain have started to attract considerable interest in recent years. With indisputable evidence showing the wide-distribution of Cb 2 Rs in the brain of different species, they are no longer considered just peripheral receptors. However, in contrast to Cb 1 Rs, the functionality of central Cb 2 Rs remains largely unexplored. Here we review recent studies on hippocampal Cb 2 Rs. While conflicting results about their function have been reported, we have made significant progress in understanding the involvement of Cb 2 Rs in modulating cellular properties and network excitability. Moreover, Cb 2 Rs have been shown to be expressed in different subregions of the hippocampus, challenging our prior understanding of the endocannabinoid system. Although more insight into their functional roles is necessary, we propose that targeting hippocampal Cb 2 Rs may offer novel therapies for diseases related to memory and adult neurogenesis deficits.
Chapter
The endocannabinoid 2-arachidonoylglycerol (2-AG) exerts its physiological action by binding to and functionally activating type-1 (CB1) and type-2 (CB2) cannabinoid receptors. It is thought to be produced through the action of sn-1 selective diacylglycerol lipase (DAGL) that catalyzes 2-AG biosynthesis from sn-2-arachidonate-containing diacylglycerols. Different methodological approaches for measuring DAGL activity in biological samples are now available. Here, a highly sensitive radiometric assay to assess DAGL activity, by using 1-oleoyl[1-14C]-2-arachidonoylglycerol as the substrate, is reported. All the steps required to perform lipid extraction, fractionation by thin-layer chromatography (TLC), and quantification of radiolabeled [14C]-oleic acid via scintillation counting are described in detail.Key words2-arachidonoylglycerolDiacilglycerol lipaseRadiometric assayThin layer chromatography
Article
Mechanistic insights into cannabinoid signaling could improve therapeutic applications.
Article
Full-text available
At the intersection of science and medicine, government policy, and pop culture, cannabis has prompted society since the beginning of recorded history. And yet, there is comparatively little replicable data on the plant, its constituents, and their capacity to modify human physiology. Over the past decades, several findings have pointed toward the importance of the endogenous cannabinoid system in maintaining homeostasis, making it an important target for various diseases. Here, we summarize the current state of knowledge on endogenous- and plant-based cannabinoids, address the issues related to cannabinoid-based drug discovery, and incite efforts to utilize their polypharmacological profile toward tackling diseases with a complex underlying pathophysiology. By fusing modern science and technology with the empirical data that has been gathered over centuries, we propose an outlook that could help us overcome the dearth of innovation for new drugs and synchronously redefine the future of drug discovery. Simultaneously, we call attention to the startling disconnect between the scientific, regulatory, and corporate entities that is becoming increasingly evident in this booming industry.
Article
Full-text available
The minimum alveolar concentration MAC of isoflurane was measured in rats chronically treated with WIN 55,212-2. Methods: The MAC of isoflurane was determined in 24 male rats from expiratory samples at time of tail clamping under the following conditions: without treatment MAC(ISO), in rats treated for 21 days with WIN 55,212-2 MAC(ISO + WIN55), and in rats 8 days after stopping treatment with WIN 55,212-2 (MACISO + WIN55 + 8D). Results: The MAC(ISO) was 1.32 ± 0.06. In the MAC(ISO + WIN55) group, the MAC increased to 1.69 ± 0.09 (28%, p-value ≤ (0.0001). Eight days after stopping treatment with WIN55, the MAC did not decrease significantly, 1.67 ± 0.07 (26%, p-value ≤ 0.0001). Conclusions: The administration of WIN 55,212-2 for 21 days increases the MAC of isoflurane in rats. This effect does not disappear 8 days after discontinuation of treatment with the synthetic cannabinoid.
Article
Full-text available
Introduction: In the last two decades, our understanding of the therapeutic utility and medicinal properties of cannabis has greatly changed. This change has been accompanied by widespread cannabis use in various communities and different age groups, especially within the United States. With this increase, we should consider the potential effects of cannabis-hemp on general public health and how they could alter therapeutic outcomes. Material and methods: The present investigation examined cannabis use for recreational and therapeutic use and a review of pertinent indexed literature was performed. The focused question evaluates "how cannabis or hemp products impact health parameters and do they provide potential therapeutic value in dentistry, and how do they interact with conventional medicines (drugs)." Indexed databases (PubMed/Medline, EMBASE) were searched without any time restrictions but language was restricted to English. Results: The review highlights dental concerns of cannabis usage, the need to understand the endocannabinoid system (ECS), cannabinoid receptor system, its endogenous ligands, pharmacology, metabolism, current oral health, and medical dilemma to ascertain the detrimental or beneficial effects of using cannabis-hemp products. The pharmacological effects of pure cannabidiol (CBD) have been studied extensively while cannabis extracts can vary significantly and lack empirical studies. Several metabolic pathways are affected by cannabis use and could pose a potential drug interaction. The chronic use of cannabis is associated with health issues, but the therapeutic potential is multifold since there is a regulatory role of ECS in many pathologies. Conclusion: Current shortcomings in understanding the benefits of cannabis or hemp products are limited due to pharmacological and clinical effects not being predictable, while marketed products vary greatly in phytocompounds warrant further empirical investigation. Given the healthcare challenges to manage acute and chronic pain, this review highlights both cannabis and CBD-hemp extracts to help identify the therapeutic application for patient populations suffering from anxiety, inflammation, and dental pain.
Article
Full-text available
Cannabinoids and their endogenous and synthetic analogs impact blood pressure and contribute to the incidence of hypertension. It was previously reported that the endocannabinoid system plays an important role in developing hypertension; however, it was also shown that cannabinoids elicit profound hypotension associated with hemorrhagic, cardiogenic, and endotoxic shock. This study aimed to test acute and chronic effects of an endogenous ligand of cannabinoid receptor anandamide (AEA) on blood pressure and kidney injury in vivo in conscious Dahl salt-sensitive (SS) rats. We demonstrated that acute i.v. bolus administration of a low or a high doses (0.05 or 3 mg/kg) of AEA did not affect blood pressure for 2 h after the injection in Dahl SS rats fed a normal salt diet (0.4% NaCl). Neither low nor high doses of AEA had any beneficial effects on blood pressure or kidney function. Furthermore, hypertensive rats fed a HS diet (8% NaCl) and chronically treated with 3 mg/kg of AEA exhibited a significant increase in blood pressure accompanied by increased renal interstitial fibrosis and glomerular damage at the late stage of hypertension. Western blot analyses revealed increased expression of Smad3 protein levels in the kidney cortex in response to chronic treatment with a high AEA dose. Therefore, TGF-β1/Smad3 signaling pathway may play a crucial role in kidney injury in SS hypertension during chronic treatment with AEA. Collectively, these data indicate that prolonged stimulation of cannabinoid receptors may result in aggravation of hypertension and kidney damage.
Article
In the central nervous system, oligodendrocytes synthesize the myelin, a specialized membrane to wrap axons in a discontinuous way allowing a rapid saltatory nerve impulse conduction. Oligodendrocytes express a number of growth factors and neurotransmitters receptors that allow them to sense the environment and interact with neurons and other glial cells. Depending on the cell cycle stage, oligodendrocytes may respond to these signals by regulating their survival, proliferation, migration, and differentiation. Among these signals are the endocannabinoids, lipidic molecules synthesized from phospholipids in the plasma membrane in response to cell activation. Here, we discuss the evidence showing that oligodendrocytes express a full endocannabinoid signaling machinery involved in physiological oligodendrocyte functions that can be therapeutically exploited to promote remyelination in central nervous system pathologies. MAIN POINTS: • In oligodendroglial cells there is an operational endocannabinoid signaling network. • 2‐AG contributes to the proliferation, directional migration and maturation of OPCs. • Manipulation of the endocannabinoid system exert beneficial therapeutic effects.
Article
A small library of FAAH and dual FAAH/MAGL inhibitors designed for peripheral selectivity were targeted. Of these compounds, three were identified to have desirable FAAH inhibition and reduced permeability in a PAMPA assay. Those three compounds were advanced into a MAGL inhibitor assay and one was found to be a relative selective FAAH inhibitor, FAAH to MAGL IC50 ratio of 1:27, and one was found to be more characteristic of a true dual enzyme inhibitor, FAAH to MAGL IC50 ratio of 1:4. Both compounds showed activity in an ABPP assay, blockage of TAMRA-FP labeling of FAAH and MAGL in rat eye homogenate.
Article
Diabetic complications, chiefly seen in long-term situations, are persistently deleterious to a large extent, requiring multi-factorial risk reduction strategies beyond glycemic control. Diabetic cardiomyopathy is one of the most common deleterious diabetic complications, being the leading cause of mortality among diabetic patients. The mechanisms of diabetic cardiomyopathy are multi-factorial, involving increased oxidative stress, accumulation of advanced glycation end products (AGEs), activation of various pro-inflammatory and cell death signaling pathways, and changes in the composition of extracellular matrix with enhanced cardiac fibrosis. The novel lipid signaling system, the endocannabinoid system, has been implicated in the pathogenesis of diabetes and its complications through its two main receptors: Cannabinoid receptor type 1 and cannabinoid receptor type 2, alongside other components. However, the role of the endocannabinoid system in diabetic cardiomyopathy has not been fully investigated. This review aims to elucidate the possible mechanisms through which cannabinoids and the endocannabinoid system could interact with the pathogenesis and the development of diabetic cardiomyopathy. These mechanisms include oxidative/ nitrative stress, inflammation, accumulation of AGEs, cardiac remodeling, and autophagy. A better understanding of the role of cannabinoids and the endocannabinoid system in diabetic cardiomyopathy may provide novel strategies to manipulate such a serious diabetic complication.
Article
Background: Activation of signaling effectors by G-protein coupled receptors (GPCRs) depends on different molecular mechanisms triggered by conserved amino acid residues. Although studies have focused on the G-protein signaling state, the mechanism for β-arrestin signaling by CB1 is not yet well defined. Studies have indicated that transmembrane helix 7 (TMH7) and the highly conserved NPXXY motif can be subject to different conformational changes in response to biased ligands and could therefore participate in a molecular mechanism to trigger β-arrestin recruitment. Objective: To investigate the effect of mutations in the NPXXY motif on different signaling pathways activated by the CB1 receptor. Materials and Methods: Point mutations of the NPXXY motif and associated residues were generated in the CB1 receptor using site-directed mutagenesis and transfection into HEK-293 cells. Signaling by wild-type and mutant receptors was analyzed by quantifying inhibition of cAMP, and by β-arrestin recruitment assays. Results: We found that N7.49 and Y7.53 are essential for β-arrestin recruitment by CB1. N7.49A and Y7.53F impair β-arrestin signaling, with no effect on G-protein signaling. We found a regulatory role for residue I2.43; I2.43 interacts with Y7.53, affecting its positioning. Reducing steric bulk at I2.43 (I2.43A) enhances β-arrestin1 recruitment, while introducing a polar residue (I2.43T) reduces β-arrestin recruitment. Conclusions: These findings point to a novel mechanism for β-arrestin recruitment, implicating amino acids in the NPXXY motif as critical for the putative β-arrestin biased conformational state of Class A GPCRs.
Article
Endocannabinoid signalling is considered one of the most important modulatory systems in a whole organism. Research has yielded great insight on the mechanisms that link endocannabinoids and metabolic functions. Here, we provide a brief overview of the metabolic roles of endocannabinoids in tissue, cellular and subcellular-dependent mechanisms. In general, we point out how the central and peripheral control of body energy metabolism likely represents the main function of type-1 cannabinoid receptors. More specifically, we focus on recent advances underlying mechanisms of endocannabinoid control of cell metabolism through the modulation of the functions of specific organelles. While highlighting a historical summary and summarizing past discoveries, this short review aims at proposing future open questions for a field that does not stop surprising researchers with unexpected and exciting discoveries. Busquets-García et al. provide a historical perspective of the discovery of endocannabinoid signalling and summarize the most recent findings on the role of endocannabinoids in the regulation of intracellular metabolism and its implications for whole-body homeostasis.
Article
Δ9-THC (the main active compound from Cannabis sativa) and related cannabinoids have been used as drugs of abuse and as medications. They induce a complex set of emotional responses in humans and experimental animals, consisting of either anxiolysis or heightened anxiety. These discrepant effects pose a major challenge for data reproducibility and for developing new cannabinoid-based medicines. In this study, we review and analyze previous data on cannabinoids and anxiety-like behavior in experimental animals. Systematic review and meta-analysis on the effects of type-1 cannabinoid receptor agonists (full or partial, selective or not) in rodents exposed to the elevated plus maze, a widely used test of anxiety-like behavior. Cannabinoids tend to reduce anxiety-like behavior if administered at low doses. THC effects are moderated by the dose factor, with anxiolytic- and anxiogenic-like effects occurring at low-dose (0.075-1 mg/kg) and high-dose (1-10 mg/kg) ranges, respectively. However, some studies report no effect at all regardless of the dose tested. Finally, motor impairment represents a potential confounding factor when high doses are administered. The present analysis may contribute to elucidate the experimental factors underlying cannabinoid effects on anxiety-like behavior and facilitate data reproducibility in future studies.
Chapter
Astrocytes are glial cells in the central nervous system (CNS), which contribute to CNS health and disease by participating in homeostatic, structural, and metabolic processes that play an essential role in facilitating synaptic transmission between neurons. Schizophrenia (SCZ) is a neuropsychiatric disorder associated with various positive and negative behaviors and interruption of executive function and cognition thought to be due partly to aberrations in signaling within neural networks. Recent research has demonstrated that astrocytes play a role in SCZ through various effects, including influencing immune system function, altering white matter, and mediating changes in neurotransmitters. Astrocytes are also known to play a role in inducing SCZ-associated changes in neuroplasticity, which includes alterations in synaptic strength and neurogenesis. Also, astrocyte abnormalities are linked to neurobehav-ioral impairments seen at the clinical level. The present chapter details general information on SCZ. It highlights the role of astrocytes in SCZ at molecular and behavioral levels, including neural changes seen in the disease, and the therapeutic implications of targeting astrocytes in SCZ.
Article
Opioid use disorder reflects a major public health crisis of morbidity and mortality where opioid withdrawal often contributes to continued use. However, current medications that treat opioid withdrawal symptoms are limited by their abuse liability or lack of efficacy. Although cannabinoid 1 (CB1) receptor agonists, including Δ9-tetrahydrocannabinol (THC), ameliorate opioid withdrawal in both clinical and pre-clinical studies of opioid dependence, this strategy elicits cannabimimetic side effects as well as tolerance and dependence following repeated administration. Alternatively, CB1 receptor positive allosteric modulators (PAMs) enhance CB1 receptor signaling and show efficacy in rodent models of pain and cannabinoid dependence but lack cannabimimetic side effects. We hypothesize that the CB1 receptor PAM, ZCZ011, attenuates naloxone-precipitated withdrawal signs in opioid-dependent mice. Accordingly, male and female mice given an escalating dosing regimen of oxycodone, a widely prescribed opioid, and challenged with naloxone displayed withdrawal signs that included diarrhea, weight loss, jumping, paw flutters, and head shakes. ZCZ011 fully attenuated naloxone-precipitated withdrawal-induced diarrhea and weight loss and reduced paw flutters by approximately half, but its effects on head shakes were unreliable and it did not affect jumping behavior. The anti-diarrheal and anti-weight loss effects of ZCZ0111 were reversed by a CB1, not a CB2, receptor antagonist and were absent in CB1 (-/-) mice, suggesting a necessary role of CB1 receptors. Collectively, these results indicate that ZCZ011 completely blocked naloxone-precipitated diarrhea and weight loss in oxycodone-dependent mice and suggest that CB1 receptor PAMs may offer a novel strategy to treat opioid dependence. Significance Statement Opioid use disorder represents a serious public health crisis in which current medications used to treat withdrawal symptoms are limited by abuse liability and/or side effects. The CB1 receptor positive allosteric modulator (PAM), ZCZ011, which lacks overt cannabimimetic behavioral effects, ameliorated naloxone-precipitated withdrawal signs through a CB1 receptor mechanism of action in a mouse model of oxycodone dependence. These results suggest that CB1 receptor PAMs may represent a viable strategy to treat opioid withdrawal.
Article
Full-text available
Enzymatic activities have been identified which catalyze both the hydrolysis and synthesis of arachidonylethanolamide (anandamide). Anandamide was taken up by neuroblastoma and glioma cells in culture, but it did not accumulate since it was rapidly degraded by an amidase activity that resided mainly in the membrane fractions. This amidase activity was expressed in brain and the majority of cells and tissues tested. Phenylmethylsulfonyl fluoride (PMSF) was found to be a potent inhibitor of this amidase. A catalytic activity for the biosynthesis of anandamide from ethanolamine and arachidonic acid was readily apparent in incubations of rat brain homogenates. The stability of anandamide in serum and its rapid breakdown in cells and tissues are consistent with the observation that it is active when administered systemically, and its duration of action will be regulated by its rate of degradation in cells.
Article
Full-text available
Arachidonylethanolamide, an arachidonic acid derivative in porcine brain, was identified in a screen for endogenous ligands for the cannabinoid receptor. The structure of this compound, which has been named "anandamide," was determined by mass spectrometry and nuclear magnetic resonance spectroscopy and was confirmed by synthesis. Anandamide inhibited the specific binding of a radiolabeled cannabinoid probe to synaptosomal membranes in a manner typical of competitive ligands and produced a concentration-dependent inhibition of the electrically evoked twitch response to the mouse vas deferens, a characteristic effect of psychotropic cannabinoids. These properties suggest that anandamide may function as a natural ligand for the cannabinoid receptor.
Article
Full-text available
Marijuana and many of its constituent cannabinoids influence the central nervous system (CNS) in a complex and dose-dependent manner. Although CNS depression and analgesia are well documented effects of the cannabinoids, the mechanisms responsible for these and other cannabinoid-induced effects are not so far known. The hydrophobic nature of these substances has suggested that cannabinoids resemble anaesthetic agents in their action, that is, they nonspecifically disrupt cellular membranes. Recent evidence, however, has supported a mechanism involving a G protein-coupled receptor found in brain and neural cell lines, and which inhibits adenylate cyclase activity in a dose-dependent, stereoselective and pertussis toxin-sensitive manner. Also, the receptor is more responsive to psychoactive cannabinoids than to non-psychoactive cannabinoids. Here we report the cloning and expression of a complementary DNA that encodes a G protein-coupled receptor with all of these properties. Its messenger RNA is found in cell lines and regions of the brain that have cannabinoid receptors. These findings suggest that this protein is involved in cannabinoid-induced CNS effects (including alterations in mood and cognition) experienced by users of marijuana.
Article
Full-text available
The major active ingredient of marijuana, delta 9-tetrahydrocannabinol (delta 9-THC), has been used as a psychoactive agent for thousands of years. Marijuana, and delta 9-THC, also exert a wide range of other effects including analgesia, anti-inflammation, immunosuppression, anticonvulsion, alleviation of intraocular pressure in glaucoma, and attenuation of vomiting. The clinical application of cannabinoids has, however, been limited by their psychoactive effects, and this has led to interest in the biochemical bases of their action. Progress stemmed initially from the synthesis of potent derivatives of delta 9-THC, and more recently from the cloning of a gene encoding a G-protein-coupled receptor for cannabinoids. This receptor is expressed in the brain but not in the periphery, except for a low level in testes. It has been proposed that the nonpsychoactive effects of cannabinoids are either mediated centrally or through direct interaction with other, non-receptor proteins. Here we report the cloning of a receptor for cannabinoids that is not expressed in the brain but rather in macrophages in the marginal zone of spleen.
Article
Full-text available
Arachidonylethanolamide (anandamide), a candidate endogenous cannabinoid ligand, has recently been isolated from porcine brain and displayed cannabinoid-like binding activity to synaptosomal membrane preparations and mimicked cannabinoid-induced inhibition of the twitch response in isolated murine vas deferens. In this study, anandamide and several congeners were evaluated as cannabinoid agonists by examining their ability to bind to the cloned cannabinoid receptor, inhibit forskolin-stimulated cAMP accumulation, inhibit N-type calcium channels, and stimulate one or more functional second messenger responses. Synthetic anandamide, and all but one congener, competed for [3H]CP55,940 binding to plasma membranes prepared from L cells expressing the rat cannabinoid receptor. The ability of anandamide to activate receptor-mediated signal transduction was evaluated in Chinese hamster ovary (CHO) cells expressing the human cannabinoid receptor (HCR, termed CHO-HCR cells) and compared to control CHO cells expressing the muscarinic m5 receptor (CHOm5 cells). Anandamide inhibited forskolin-stimulated cAMP accumulation in CHO-HCR cells, but not in CHOm5 cells, and this response was blocked with pertussis toxin. N-type calcium channels were inhibited by anandamide and several active congeners in N18 neuroblastoma cells. Anandamide stimulated arachidonic acid and intracellular calcium release in both CHOm5 and CHO-HCR cells and had no effect on the release of inositol phosphates or phosphatidylethanol, generated after activation of phospholipase C and D, respectively. Anandamide appears to exhibit the essential criteria required to be classified as a cannabinoid/anandamide receptor agonist and shares similar nonreceptor effects on arachidonic acid and intracellular calcium release as other cannabinoid agonists.
Article
Full-text available
Although a receptor exists for cannabinoid drugs, it is uncertain which pharmacological actions this receptor mediates. This structure-activity relationship investigation was initiated to determine which effects might correspond to binding affinity for the cannabinoid receptor, as well as to explore the binding requirements of this site. The ability of nearly 60 cannabinoids to displace [3H]CP-55,940 [(-)-3-[2-hydroxy-4-(1,1-dimethylheptyl) phenyl]-4-[3-hydroxy propyl] cyclohexan-1-ol] was determined before establishing correlations between receptor affinity and in vivo pharmacological potency. Analysis of [3H]CP-55,940 binding indicated a Hill coefficient of 0.97, a Bmax of 499 pM (3.3 pmol/mg of protein) and an apparent Kd of 924 pM. Closer inspection indicated the binding assay exhibited "zone B" characteristics, and use of correction equations indicated a true Kd for CP-55,940 of 675 pM. The structure-activity relationship indicated the importance of side chain structure to high-affinity binding, with the most potent analogs (K1 < 10 nM) possessing either a dimethylheptyl side-chain, a similarly complex branched side chain or a halogen substituent at the 5' position. Comparative analysis of K1 values to in vivo potency in a mouse model indicated a high degree of correlation between parameters for the depression of spontaneous locomotor activity (r = 0.91) and for the production of antinociception (r = 0.90), hypothermia (r = 0.89) and catalepsy (r = 0.85). Similarly high correlations were demonstrated between binding affinity and in vivo potency in both the rat drug discrimination model (r = 0.81) and for psychotomimetic activity in humans (r = 0.88).(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Full-text available
Marijuana and many of its constituent cannabinoids influence the central nervous system (CNS), probably through the cannabinoid receptor, which has recently been cloned in rat and human. While numerous reports have also described effects of cannabinoids on the immune system, the observation of both mRNA and cannabinoid receptor has hitherto been exclusively confined to the brain, a reported detection in the testis being the sole example of its presence at the periphery. Here we report the expression of the cannabinoid receptor on human immune tissues using a highly sensitive polymerase-chain-reaction-based method for mRNA quantification. We show that, although present in a much lower abundance than in brain, cannabinoid receptor transcripts are found in human spleen, tonsils and peripheral blood leukocytes. The distribution pattern displays important variations of the mRNA level for the cannabinoid receptor among the main human blood cell subpopulations. The rank order of mRNA levels in these cells is B cells > natural killer cells > or = polymorphonuclear neutrophils > or = T8 cells > monocytes > T4 cells. Cannabinoid-receptor mRNA, which is also found in monocytic, as well as T and B leukemia cell lines but not in Jurkat cells, presents a great diversity of expression on these cells as well, B-cell lines expressing a much higher level than T-cell lines. The cannabinoid receptor PCR products from leukocytes and brain are identical both in size and sequence suggesting a strong similarity between central and peripheral cannabinoid receptors. The expression of this receptor was demonstrated on membranes of the myelomonocytic U937 cells using the synthetic cannabinoid [3H]CP-55940 as ligand. The Kd determined from Scatchard analysis was 0.1 nM and the Bmax for membranes was 525 fmol/mg protein. The demonstration of cannabinoid-receptor expression at both mRNA and protein levels on human leukocytes provides a molecular basis for cannabinoid action on these cells.
Chapter
The dose—response relation of many agonists yield sigmoidal (S-shaped) curves when the response is plotted against the logarithm of the dose (see Figure 8.1). There is no generally accepted theory that explains the shape of such curves; yet, we find that such curves are often approximately linear between 20% and 80% of the maximum response. In particular, many isolated tissue preparations display this linear segment. The data in the 20%–80% region may therefore be subjected to linear regression as given in Procedure 3, in which y = effect, or percent effect, and x = log dose. The regression line so determined might be used in the comparison of potency (Procedure 10) or in the analysis of the action of a competitive antagonist (Procedure 15). In each of these applications the regression lines are made parallel, and equieffective doses are determined.
Article
The ability of Δ9-Tetrahydrocannabinol (Δ9-THC) to modulate adenylate cyclase activity in mouse spleen cells was investigated. These studies were prompted by the recent identification and cloning of a G-protein coupled cannabinoid receptor localized in certain regions of the brain and the potential for a common mechanism between cannabinoid-mediated CNS effects and immunosuppression. Temporal addition studies were initially performed to identify the period of time when spleen cells in culture were most susceptible to the inhibitory effects of Δ-THC, as measured by the day 5 IgM antibody forming cell response. Δ9-THC was only inhibitory when added to spleen cell cultures during the first 2 hr following antigen sensitization. In light of this time course, adenylate cyclase activity was measured in spleen cell incubated in the presence of 22μM Δ9-THC for 5 min and subsequently stimulated with forskolin. Δ9-THC treated spleen cells demonstrated a 33% inhibition and a 66% inhibition in intracellular cAMP after a 5 or 15 min stimulation with forskolin, respectively. These studies suggest that inhibition of immune function by Δ9-THC may be mediated through the inhibition of intracellular cAMP early after antigen stimulation.
Article
Extensive behavioral and biochemical characterization of cannabinoid-mediated effects on the central nervous system has revealed at least three lines of evidence supporting the role of a putative guanine nucleotide-binding protein-coupled cannabinoid receptor for cannabimimetic effects, (i) stereoselectivity, (ii) inhibition of the adenylate cyclase/cAMP second messenger system, and (iii) radioligand-binding studies with the synthetic cannabinoid [3H]CP-55,940 indicating a high degree of specific binding to brain tissue preparations. Based on recent findings from our laboratory demonstrating that delta 9-tetrahydrocannabinol markedly inhibited forskolin-stimulated cAMP accumulation in mouse spleen cells, the presence of a guanine nucleotide-binding protein-coupled cannabinoid receptor associated with mouse spleen cells and its functional role in immune modulation were investigated. In the present studies, stereoselective immune modulation was observed with the synthetic bicyclic cannabinoid (-)-CP-55,940 versus (+) CP-56,667 and with 11-OH-delta 8-tetrahydrocannabinol-dimethylheptyl, (-)-HU-210 versus (+)-HU-211. In both cases, the (-)-enantiomer demonstrated greater immunoinhibitory potency than the (+)-isomer, as measured by the in vitro sheep red blood cell antibody-forming cell response. Radioligand binding studies produced a saturation isotherm exhibiting approximately 45-65% specific binding to mouse spleen cells. Scatchard analysis demonstrated a single binding site on spleen cells, possessing a Kd of 910 pM and a Bmax of approximately 1000 receptors/spleen cell. RNA polymerase chain reaction of isolated splenic RNA using specific primers for the cannabinoid receptor resulted in the amplification of a 854-kilobase predicted product that hybridized with cannabinoid receptor cDNA, demonstrating the presence of cannabinoid receptor mRNA in mouse spleen. Together, these findings strongly support the role of a cannabinoid receptor in immune modulation by cannabimimetic agents.
Article
Opening of the pyran ring of delta 9-tetrahydrocannabinol (THC) produces cannabidiol, a bicyclic cannabinoid devoid of many pharmacological properties produced by delta 8-THC or delta 9-THC. Interestingly, the bicyclic compound CP-47,497 (VI) has been described as producing many of the pharmacological effects produced by delta 9-THC, and another related bicyclic analog CP-55,940 (XIV) has been used to successfully define a cannabinoid binding site. A series of 16 bicyclic analogs of VI and XIV were evaluated and compared with the pharmacological profile of cannabidiol, delta 8-THC and delta 9-THC. The goals of the studies described herein were to determine whether these bicyclic analogs possess similar pharmacological properties of delta 9-THC, to compare pharmacological activity after s.c. and i.v. administration, and to evaluate the structure-activity relationship of this series of analogs for further insight into cannabinoid mechanism of action. Each analog was evaluated for its ability to produce hypoactivity, hypothermia, antinociception and catalepsy in mice. The ED50 values generated from these assays were averaged to provide an index of activity. The ED50 values for delta 9-THC varied from 1.0 to 1.5 mg/kg, giving an overall index of activity of 1.3. The index for delta 8-THC was 6.0, making this isomer 4-fold less potent. Although several bicyclic analogs (V, VI, VII, VIII, XI, XII, XIV and XVI) proved to be truly cannabimimetic, three (IV, IX and X) were sufficiently unique to be classified as noncannabimimetic. The index of activity of cannabimimetic bicyclic analogs varied from 0.2 to 2.2, although some minor differences between the bicyclics and delta 9-THC exist.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Delta-9-tetrahydrocannabinol (THC) is the major psychoactive component of marijuana. This substance has been shown to elicit a spectrum of effects in vitro and in experimental animals. The drug decreases host resistance to viruses (1–3) and bacteria (1), alters cellular morphology and function (4–10), and inhibits RNA, DNA, and protein synthesis (11–13). These effects on macromolecular synthesis suggest that THC may elicit its immunosuppressive effects by altering the expression and/or secretion of effector molecules. Macrophages play a central role in the regulation of immune responsiveness. These cells act “early” in a primary viral infection by exerting intrinsic and extrinsic antiviral activities (17,18), and play a central role in host resistance by their capacity to produce interferons and monokines and to function as antigen-presenting cells (19,20). Responsive macrophages undergo a multi-step process to full activation (21–23). Each of these stages in the activation process is associated with discrete functional activities. Responsive macrophages ingest and degrade bacteria and viruses. A hallmark of fully activated macrophages, on the other hand, is their capacity to destroy tumor cells and virus-infected cells. These effector functions are induced in response to a variety of signals, including bacteria and bacterial cell wall products (i.e., lipopolysaccharide). The sequential development of responsive macrophages to full activation is accompanied by the expression of defined, quantifiable protein markers which reflect the potential of the macrophage to execute different functional activities.
Article
The major psychoactive cannabinoid found in marijuana is delta-1-tetrahydrocannabinol, designated delta-1-THC. This cannabinoid is but one of 62 cannabinoids that have been identified in the plant (1). In addition to the cannabinoids, 364 organic compounds have also been identified. Cannabinoids are defined as naturally occurring 21 carbon compounds of cannabis including analogues of these compounds and their metabolites (2,3). Delta-1-THC as well as other cannabinoids, e.g., cannabinol and cannabidiol affect growth, development and reproductive activity and a variety of cellular systems including the immune system (4–8).
Article
The determination and characterization of a cannabinoid receptor from brain are reported. A biologically active bicyclic cannabinoid analgetic CP-55,940 was tritium-labeled to high specific activity. Conditions for binding to rat brain P2 membranes and synaptosomes were established. The pH optimum was between 7 and 8, and specific binding could be eliminated by heating the membranes to 60 degrees. Binding to the P2 membranes was linear within the range of 10 to 50 micrograms of protein/ml. Specific binding (defined as total binding displaced by 1 microM delta 9-tetrahydrocannabinol (delta 9-THC) or 100 nM desacetyllevonantradol) was saturable. The Kd determined from Scatchard analysis was 133 pM, and the Bmax for rat cortical P2 membranes was 1.85 pmol/mg of protein. The Hill coefficient for [3H]CP-55,940 approximated 1, indicating that, under the conditions of assay, a single class of binding sites was determined that did not exhibit cooperativity. The binding was rapid (kon approximately 2.6 x 10(-4) pM-1 min-1) and reversible (Koff approximately 0.016 min-1) and (koff' greater than 0.06 min-1). The two Kd values estimated from the kinetic constants approximately 55 pM and exceeded 200 pM, respectively. The binding of the agonist ligand [3H]CP-55,940 was decreased by the nonhydrolyzable GTP analog guanylylimidodiphosphate. The guanine nucleotide induced a more rapid dissociation of the ligand from the binding site, consistent with an allosteric regulation of the putative receptor by a G protein. The binding was also sensitive to MgCl2 and CaCl2. Binding of [3H]CP-55,940 was displaced by cannabinoid drugs in the following order of potency: CP-55,940 greater than or equal to desacetyllevonantradol greater than 11-OH-delta 9-THC = delta 9-THC greater than cannabinol. Cannabidiol and cannabigerol displaced [3H]CP-55,940 by less than 50% at 1 microM concentrations. The (-)-isomer of CP-55,940 displaced with 50-fold greater potency than the (+)-isomer. This pharmacology is comparable to both the inhibition of adenylate cyclase in vitro and the analgetic activity of these compounds in vivo. The criteria for a high affinity, stereoselective, pharmacologically distinct cannabinoid receptor in brain tissue have been fulfilled.
Article
The many studies that have been included in this review suggest that cannabinoids have ubiquitous effects on biological systems. These results also underscore the intensity to which cannabinoids have been studied. While there are numerous reasons for the prodigious amount of cannabinoid research, a major stimulus has been the desire to identify a specific biochemical event or pathway that is responsible for the expression of delta 9-THC's unique psychoactivity. It is the hope that delta 9-THC, as with all centrally acting drugs, might serve as an important tool for achieving a better understanding of the central nervous system. As discussed in this review, the psychoactivity of cannabinoids might best be described as a composite of numerous effects. If that is indeed the case, then it would seem logical that these centrally mediated effects do not arise from a single biochemical alteration, but rather from multiple actions. Of course, a major problem arises when one attempts to establish a relationship between cause and effect when multiple mechanisms and effects are involved. An initial approach to reducing the complexity of elucidation of mechanism of action should involve attempts to distinguish those cannabinoid actions which result in specific effects (psychoactivity) from those which produce non-psychoactive effects (such as general depression). There are several fundamental principles that can be used to assess specificity, including concentration or dose of the drug that is required to produce a given effect. Low doses of delta 9-THC are capable of producing the psychoactivity that is unique to cannabinoids, whereas higher doses may produce effects that are both specific and nonspecific for cannabinoids. Unfortunately, establishing this basic tenet for delta 9-THC has proven to be difficult. It has not been possible to establish the concentration of delta 9-THC at its site of action that is necessary to produce a given pharmacological effect. While it is a simple matter to measure the concentration of cannabinoids in either a whole tissue or an incubation medium, the hydrophobicity of cannabinoids dramatically affects their affinity for, and hence concentration in, the biochemical components of the tissue. If the concentration of delta 9-THC could be measured at its site of action, then the relevance of many of its pharmacological effects could be adequately determined. Two possible mechanisms by which cannabinoids might produce psychoactivity are membrane perturbation and receptor interactions, and indeed, both mechanisms have received considerable attention.(ABSTRACT TRUNCATED AT 400 WORDS)
Article
The cellular mediated immunity of 51 young chronic marihuana smokers. as evaluated by the lyomphocyte response in vitro to allogeneic cells and to phytohemagglutinin, was significantly decreased and similar to that of patients in whom impairment of T (thymus derived) cell immunity is known to occur. This inhibition of blastogenesis might be related to an impairment of DNA synthesis.
Article
1. A bioassay for cannabis, called the ring test, has been developed in which the percentage of the total time spent on a horizontal wire ring during which a mouse remains completely immobile is recorded.2. The effect of cannabis on mobility is a dose-related, graded response.3. Threshold doses of cannabis extract are 12.5 mg/kg when injected intravenously, and 100 mg/kg when injected intraperitoneally or subcutaneously.4. The method provides a measure of the ;cataleptic' effect of cannabis. Chlorpromazine in doses of 1 mg/kg upwards also produces the effect but barbitone does not.5. It is concluded that Delta(1)-tetrahydrocannabinol (Delta(1)-THC) is largely responsible for the effect of cannabis extract on mobility; the potency ratio of Delta(1)-THC to cannabis extract is between 10 and 20. Delta(1)-Tetrahydrocannabidivarol (Delta(1)-THD) also affects mobility but is less active than Delta(1)-THC. Cannabidiol has no effect when injected intraperitoneally in doses up to 100 mg/kg.
Article
Anandamide (20:3, n - 6) (homo-gamma-linolenylethanolamide) and anandamide (22:4, n - 6) (7,10,13,16-docosatetraenylethanolamide) are known to be present in porcine brain and to undergo specific binding to cannabinoid binding sites. We have now shown that both compounds inhibit the electrically evoked twitch response of the mouse isolated vas deferens (IC50 = 99.3 and 95.5 nM respectively) indicating that they also have the ability to elicit a response. As electrically evoked contractions of the mouse vas deferens are also inhibited by the endogenous cannabinoid, anandamide (20:4, n - 6) (arachidonylethanolamide; IC50 = 52.7 nM), and by other cannabinoids, we conclude that anandamide (20:3, n - 6) and (22:4, n - 6), may, together with anandamide (20:4, n - 6), serve as endogenous cannabinoid receptor agonists. This conclusion is supported by our other main finding, that vasa deferentia show tolerance to the inhibitory effects of anandamide (20:3, n - 6) and anandamide (22:4, n - 6) when obtained from mice subjected to a delta 9-tetrahydrocannabinol pretreatment that is known to induce cannabinoid tolerance.
Article
Cannabinoid compounds, including the major psychoactive component of marihuana, delta 9-tetrahydrocannabinol (delta 9-THC), have been widely established as being inhibitory on a broad array of humoral and cell-mediated immune responses. The presence of cannabinoid receptors has been identified recently on mouse spleen cells, which possess structural and functional characteristics similar to those of the G-protein coupled cannabinoid receptor originally identified in rat brain. These findings, together with those demonstrating that delta 9-THC inhibits adenylate cyclase in splenocytes, strongly suggest that certain aspects of immune inhibition by cannabinoids may be mediated through a cannabinoid receptor-associated mechanism. The objective of the present studies was to determine whether inhibition of adenylate cyclase is relevant to mouse spleen cell immune function and, if so, whether this inhibition is mediated through a Gi-protein coupled mechanism as previously described in neuronal tissue. Spleen cell activation by the phorbol ester phorbol-12-myristate-13-acetate (PMA), plus the calcium ionophore ionomycin, produced a rapid but transient increase in cytosolic cAMP, which was inhibited completely by immunosuppressive concentrations of delta 9-THC (22 microM) and the synthetic bicyclic cannabinoid CP-55940 (5.2 microM), which produced no effect on cell viability. Inhibition by cannabinoids of lymphocyte proliferative responses to PMA plus ionomycin and sheep erythrocyte (sRBC) IgM antibody-forming cell (AFC) response, was abrogated completely by low concentrations of dibutyryl-cAMP (10-100 microM). Inhibition of the sRBC AFC response by both delta 9-THC (22 microM) and CP-55940 (5.2 microM) was also abrogated by preincubation of splenocytes for 24 hr with pertussis toxin (0.1-100 ng/mL). Pertussis toxin pretreatment of spleen cells was also found to directly abrogate cannabinoid inhibition of adenylate cyclase, as measured by forskolin-stimulated accumulation of intracellular cAMP. These results indicate that inhibition of the sRBC AFC response by cannabinoids is mediated, at least in part, by inhibition of adenylate cyclase through a pertussis toxin-sensitive Gi-protein coupled cannabinoid receptor. Additionally, these studies further support the premise that cAMP is an important mediator of lymphocyte activation.
Article
Anandamide (arachidonylethanolamide), an endogenous ligand of the cannabinoid receptor, was recently isolated from porcine brain. We report here for the first time on the effect of this ligand on the hypothalamo-pituitary adrenal (HPA) axis in comparison to that of the plant cannabinoid delta 9-tetrahydrocannabinol (THC). Intracerebroventricular injection of anandamide or THC (50 or 150 micrograms/rat) increased significantly the serum levels of ACTH and corticosterone in a dose-dependent manner and caused a pronounced depletion of CRF-41 in the median eminence. These data suggest that anandamide parallels THC in activating the HPA axis via mediation of a central mechanism which involves the secretion of CRF-41.
Article
Anandamide (arachidonylethanolamide) is a compound recently isolated from porcine brain as a putative endogenous ligand at cannabinoid receptors. The present studies examined the effects of anandamide on cannabinoid receptor binding sites and adenylyl cyclase in rat brain membranes. Receptor binding experiments, conducted at 25 degrees for 90 min, apparently resulted in significant degradation of anandamide, since anandamide (10 microM) had little effect on [3H]WIN 55212-2 binding in cerebellar membranes. Addition of the general serine protease inhibitor phenylmethylsulfonyl fluoride (PMSF) protected against this degradation, resulting in an IC50 value of 90 nM for anandamide versus [3H]WIN 55212-2 binding. Anandamide inhibited adenylyl cyclase in cerebellar membranes in a GTP-dependent manner, exhibiting a maximal inhibition level slightly less than that of WIN 55212-2 and CP-55,940, with an IC50 value of 1.9 microM. The effect of anandamide on adenylyl cyclase was region-specific, with maximal inhibition occurring in cerebellum and striatum. These results suggest that anandamide acts at G-protein-coupled cannabinoid receptors in brain with properties similar to those of exogenous cannabinoids.
Article
[3H]CP-55,940, a high-affinity cannabinoid receptor ligand, was used for in vitro binding and autoradiography in peripheral tissues in the rat. Specific cannabinoid receptor binding was found to be restricted to components of the immune system, i.e., spleen, lymph nodes and Peyer's patches. Displacement studies showed that this binding is identical (similar Kd and structure-activity profile) to that in brain. Cannabinoid receptors in the immune system are confined to B lymphocyte-enriched areas, i.e., the marginal zone of the spleen, cortex of the lymph nodes and nodular corona of Peyer's patches. Specific binding is absent in T lymphocyte-enriched areas, such as the thymus and periarteriolar lymphatic sheaths of the spleen. Certain macrophage-enriched areas, i.e., liver and lung, lack specific binding. Thus, the single peripheral cell type that may contain cannabinoid receptors is the B lymphocyte. Numerous sites have dense binding that could not be displaced by excess unlabeled drug. These nonspecific sites were found in the liver, adrenal glands and sebaceous glands, which are high in fat content, and in the heart, pancreas, components of the male and female reproductive systems and the epithelium of the esophagus. Thus, the highly lipophilic nature of cannabinoids does not appear to be the sole determinant of nonspecific binding. The data suggest that cannabinoids may exert specific receptor-mediated actions on the immune system of rats. Perhaps, also at high concentrations, cannabinoids exert membrane effects at sites where they are sequestered nonspecifically.
Article
1. Mice pretreated intraperitoneally for 2 days with delta-9-tetrahydrocannabinol (delta-9-THC) at a dose of 20 mg kg-1 day-1 and then challenged intravenously with this drug, 24 h after the second pretreatment, showed a 6 fold tolerance to the hypothermic effect of delta-9-THC. This pretreatment also induced tolerance to the hypothermic effects of the cannabimimetic agents, CP 55,940 (4.6 fold) and WIN 55,212-2 (4.9 fold), but not to the hypothermic effect of the putative endogenous cannabinoid, anandamide. 2. Vasa deferentia removed from mice pretreated intraperitoneally with delta-9-THC twice at a dose of 20 mg kg-1 day-1 were less sensitive to its inhibitory effect on electrically-evoked contractions than vasa deferentia obtained from control animals. The cannabinoid pretreatment induced a 30 fold parallel rightward shift in the lower part of the concentration-response curve of delta-9-THC and a marked reduction in the maximal inhibitory effect of the drug. It also induced tolerance to the inhibitory effects on the twitch response of CP 55,940 (8.7 fold), WIN 55,212-2 (9.6 fold) and anandamide (12.3 fold). 3. The results confirm that cannabinoid tolerance can be rapid in onset and support the hypothesis that it is mainly pharmacodynamic in nature. The finding that in vivo pretreatment with delta-9-THC can produce tolerance not only to its own inhibitory effect on the vas deferens but also to that of three other cannabimimetic agents, suggests that this tissue would be suitable as an experimental model for investigating the mechanisms responsible for cannabinoid tolerance. 4. Further experiments are required to establish why tolerance to anandamide-induced hypothermia was not produced by a pretreatment with delta-9-THC that did induce tolerance to the hypothermic effects of delta-9-THC, CP 55,940 and WIN 55,212-2 and to the inhibitory effects of delta-9-THC,CP 55,940, WIN 55,212-2 and anandamide on the twitch response of the vas deferens.
Article
The cannabimimetic activity of two enantiomeric pairs of compounds structurally different from the classical cannabinoids was evaluated in rats and pigeons, trained to discriminate between the presence and absence of (-)-delta-9-tetrahydrocannabinol (THC). One pair of enantiomers [compounds (+)-HU-249 and (-)-HU-250] has a 5-membered oxygen-containing benzofuran ring; the second pair [(+)-HU-253 and (-)-HU-254] does not have an oxygen-containing ring. The onset of cannabimimetic activity was slower, and duration of action was longer for the test compounds than for THC. HU-250 exhibited cannabimimetic activity with a potency similar to THC in both species; HU-249 was 22 times less active than THC. The pattern of response rate and THC-like responding obtained with HU-249 were dissociated; THC-like responding occurred during the later test intervals when suppression of response rate was reduced. HU-250 bound to the cannabinoid receptor with a Ki of 47.6 nM, essentially identical to that of THC. HU-249 was much less active, with a Ki of 28.3 microM. The triacetate enantiomers, HU-253 and HU-254, occasioned THC-like responding in both species, HU-254 being about 4.5 times less potent than THC and 3 to 4 times more potent than HU-253. In binding, HU-253 was also less potent than HU-254. The corresponding triols were considerably more potent than the acetates; (-)-HU-256 had a Ki of 198 nM, whereas (+)-HU-255 had a Ki of 43.8 nM, comparable to that of THC.
Article
Anandamide (arachidonylethanolamide) is a brain constituent which binds to the cannabinoid receptor. We now report the first in vivo examination of this ligand. Anandamide administered i.p. in mice, caused lowering of activity in an immobility and in an open field test, and produced hypothermia and analgesia. These effects parallel those caused by psychotropic cannabinoids.
Article
A putative endogenous cannabinoid ligand, arachidonylethanolamide (termed "anandamide"), was isolated recently from porcine brain. Here we demonstrate that this compound is a specific cannabinoid agonist and exerts its action directly via the cannabinoid receptors. Anandamide specifically binds to membranes from cells transiently (COS) or stably (Chinese hamster ovary) transfected with an expression plasmid carrying the cannabinoid receptor DNA but not to membranes from control nontransfected cells. Moreover, anandamide inhibited the forskolin-stimulated adenylate cyclase in the transfected cells and in cells that naturally express cannabinoid receptors (N18TG2 neuroblastoma) but not in control nontransfected cells. As with exogenous cannabinoids, the inhibition by anandamide of the forskolin-stimulated adenylate cyclase was blocked by treatment with pertussis toxin. These data indicate that anandamide is an endogenous agonist that may serve as a genuine neurotransmitter for the cannabinoid receptor.
Molecular cloning of a human cannabinoid receptor which is also expressed in testis
  • Gerárd
Molecular characterization of a peripheral receptor for cannabinoids
  • Munro
The pharmacological activity of anandamide, a putative endogenous cannabinoid, in mice
  • Smith
Graded dose-response
  • Tallarida