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Isolation and Structure of a Brain Constituent That Binds to the Cannabinoid Receptor
Abstract
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.
... More precisely, this system is composed of two specific cannabinoid receptors (CB1 and CB2 receptors), and their endogenous ligands, namely endocannabinoids (eCBs). The eCBs are a class of lipid-based neurotransmitters, including anandamide (AEA) and 2arachidonoylglycerol (2-AG) [2,3]. Parts of the ECS are also the main enzymes responsible for eCBs biosynthesis, i.e., N-acyl-phosphatidylethanolamine-phospholipase (NAPE-PLD) and diacylglycerol lipase (DAGL), as well as degradation, including fatty acid amide hydrolase (FAAH) [4] and monoacylglycerol lipase (MAGL) [5]. ...
Alzheimer’s disease (AD) is characterized by massive neuronal death, brain atrophy, and loss of neurons and synapses, which all lead to a progressive cognitive decline. Neuroinflammation has been recently identified as one of the main causes of AD progression, and microglia cells are considered to have a central role in this process. Growing evidence suggests that cannabinoids may be used as preventive treatment for AD. An altered expression of the endocannabinoids (eCBs) and their receptors (CBRs) is reported in several neurodegenerative disorders, including AD. Moreover, the modulation of CBRs demonstrated neuroprotective effects in reducing aggregated protein deposition, suggesting the therapeutic potential of natural and synthetic CBR ligands in the treatment of neurodegenerative proteinopathies. Here, we review the current knowledge regarding the involvement of CBRs in the modulation of microglia activation phenotypes, highlighting the role of neuroinflammation in the pathogenesis of neurodegenerative diseases, like AD. We also provide an overview of recently developed candidate drugs targeting CBRs that may afford a new innovative strategy for the treatment and management of AD.
Pain is strongly associated with neuro-immune activation. Thus, the emerging role of the endocannabinoid system in neuro-inflammation is important. Acupuncture has been used for over 2500 years and is widely accepted for the management of pain. Our study aimed to investigate the effects of electroacupuncture on the regulation of cannabinoid receptor type 1 within the peripheral nervous system. Inflammatory pain was induced by injecting Complete Freund’s adjuvant to induce mechanical and thermal hyperalgesia. Electroacupuncture significantly attenuated the mechanical and thermal sensitivities, and AM251, a cannabinoid receptor type 1 antagonist, eliminated these effects. Dual immunofluorescence staining demonstrated that electroacupuncture elevated expression of cannabinoid receptor type 1, co-localized with Nav 1.8. Furthermore, electroacupuncture significantly reduced levels of Nav 1.8 and COX-2 by western blot analysis, but not vice versa as AM251 treatment. Our data indicate that electroacupuncture mediates antinociceptive effects through peripheral endocannabinoid system signaling pathway and provide evidence that electroacupuncture is beneficial for pain treatment.
The practice of pain medicine has changed dramatically over the past few years. This practical and accessible evidence-based clinical handbook provides medical and nursing professionals with in-depth and up-to-date information on the various types of chronic pain, the underlying causes, and associated symptoms. Focused primarily on the management of chronic pain, the book covers the major chronic pain conditions in the head and neck, spine, and extremities. Also, it provides invaluable guidance on various pain management techniques, including medication, physical therapy, and psychological interventions. With this knowledge, healthcare professionals will be equipped to provide more effective and compassionate care, improve patients' quality of life, and reduce the risk of chronic pain and opioid dependence. An invaluable resource for pain medicine physicians, anesthesiologiests, primary care physicians, emergency medicine physicians, and nurse anaesthetists as well as those physicians preparing for US Board certification and recertification exams.
Resolvin D2 (RvD2), an endogenous lipid mediator derived from docosahexaenoic acid, has been demonstrated to have analgesic effects. However, little is known about the mechanism underlying RvD2 in pain relief. Herein, we demonstrate that RvD2 targeted the P2X3 receptor as an analgesic. The electrophysiological activity of P2X3 receptors was suppressed by RvD2 in rat dorsal root ganglia (DRG) neurons. RvD2 pre‐application dose‐dependently decreased α,β‐methylene‐ATP (α,β‐meATP)‐induced inward currents. RvD2 remarkably decreased the maximum response to α,β‐meATP, without influencing the affinity of P2X3 receptors. RvD2 also voltage‐independently suppressed ATP currents. An antagonist of the G protein receptor 18 (GPR18), O‐1918, prevented the RvD2‐induced suppression of ATP currents. Additionally, intracellular dialysis of the Gα i/o ‐protein antagonist pertussis toxin (PTX), the PKA antagonist H89, or the cAMP analog 8‐Br‐cAMP also blocked the RvD2‐induced suppression. Furthermore, α,β‐meATP‐triggered depolarization of membrane potential along with the action potential bursts in DRG neurons were inhibited by RvD2. Lastly, RvD2 attenuated spontaneous nociceptive behaviors as well as mechanical allodynia produced by α,β‐meATP in rats via the activation of the peripheral GPR18. These findings indicated that RvD2 inhibited P2X3 receptors in rat primary sensory neurons through GPR18, PTX‐sensitive Gα i/o ‐proteins, and intracellular cAMP/PKA signaling, revealing a novel mechanism that underlies its analgesic effects by targeting P2X3 receptors. image
Endometriosis, a chronic condition affecting around 10–14% of women, is challenging to manage, due to its complex pathogenesis and limited treatment options. Research has suggested a potential role of the gut microbiota and the endocannabinoid system in the development and progression of endometriosis. This narrative review aims to explore the role of, and any potential interactions between, the endocannabinoid system (ECS) and the gut microbiota in endometriosis. This review found that both the ECS and microbiota influence endometriosis, with the former regulating inflammation and pain perception and the latter influencing immune responses and hormonal balance. There is evidence that a dysregulation of the endocannabinoid system and the gut microbiota influence endometriosis symptoms and progression via changes in CB1 receptor expression and increased circulating levels of endocannabinoids. Microbial imbalances in the gut, such as increases in Prevotella, have been directly correlated to increased bloating, a common endometriosis symptom, while increases in E. coli have supported the bacterial contamination hypothesis as a potential pathway for endometriosis pathogenesis. These microbial imbalances have been correlated with increases in inflammatory markers such as TNF-α and IL-6, both often raised in those with endometriosis. Protective effects of the ECS on the gut were observed by increases in endocannabinoids, including 2-AG, resulting in decreased inflammation and improved gut permeability. Given these findings, both the ECS and the gut microbiota may be targets for therapeutic interventions for endometriosis; however, clinical studies are required to determine effectiveness.
This book provides a holistic view of natural products and remedies that have been used to treat cancer. The editors aim to educate readers about the importance of the translational role of natural products in cancer treatment by compiling 14 chapters. The book emphasizes an integrative approach to the topic by blending traditional knowledge that supports alternative therapies with the science of phytochemicals and drug discovery technologies as a means to manage the disease.
Key topics include alternative therapies (such as aromatherapy and immune boosting herbal medications), cytotoxic and anti-cancer phytochemicals, drug delivery and discovery technologies (including high-throughput screening) and some drug targets of interest for cancer treatment (such as topoisomerases and caspases). Readers will be able to learn about natural sources of ant-cancer compounds, and the methods used by research and development experts in pharmaceutical and nutraceutical industries to isolate and formulate these compounds.
This book will be a handy resource for a wide range of readers. This includes researchers, traditional medical practitioners, PG students, Ph.D. scholars and general readers to understand the role of natural products in cancer treatment.
key features
- Explains the importance of alternative therapies in the management of cancer
- Emphasizes the ethnopharmacological approaches to cancer
- Explores natural anticancer drug libraries
- Discusses the role of modern cancer targets and the importance of in-silico tools in anticancer drug discovery
- Addresses modern drug discovery tools and drug delivery technologies concerning their applications in cancer treatment.
- Includes references for further reading
The present study aimed to elucidate the effect of 10 mg/kg Δ9-tetrahydrocannabinol (THC) on cerebellar neuronal and glial morphology, apoptosis and inflammatory gene expression using a series of histological assays including stereology, Sholl analysis, immunofluorescence and real-time qPCR in male Wistar rats. A decrease in the number of Purkinje neurons and the thickness of the granular layer in the cerebellum was reported in THC-treated rats. Increased expression of Iba-1 and arborization of microglial processes were evidence of microgliosis and morphological changes in microglia. In addition, astrogliosis and changes in astrocyte morphology were other findings associated with THC administration. THC also led to an increase in caspase-3 positive cells and a decrease in autophagy and inflammatory gene expression such as mTOR, BECN1 and LAMP2. However, there were no significant changes in the volume of molecular layers and white matter, the spatial arrangement of granular layers and white matter, or the spatial arrangement of granular layers and white matter in the cerebellum. Taken together, our data showed both neuroprotective and neurodegenerative properties of THC in the cerebellum, which require further study in the future.
Endocannabinoids were implicated in a variety of pathological conditions including anxiety and are considered promising new targets for anxiolytic drug development. The optimism concerning the potentials of this system for anxiolysis is probably justified. However, the complexity of the mechanisms affected by endocannabinoids, and discrepant findings obtained with various experimental approaches makes the interpretation of research results difficult. Here, we review the anxiety-related effects of the three main interventions used to study the endocannabinoid system: pharmacological agents active at endocannabinoid-binding sites present on both the cell membrane and in the cytoplasm, genetic manipulations targeting cannabinoid receptors, and function-enhancers represented by inhibitors of endocannabinoid degradation and transport. Binding-site ligands provide inconsistent findings probably because they activate a multitude of mechanisms concomitantly. More robust findings were obtained with genetic manipulations and particularly with function enhancers, which heighten ongoing endocannabinoid activation rather than affecting all mechanisms indiscriminately. The enhancement of ongoing activity appears to ameliorate stress-induced anxiety without consistent effects on anxiety in general. Limited evidence suggests that this effect is achieved by promoting active coping styles in critical situations. These findings suggest that the functional enhancement of endocannabinoid signaling is a promising drug development target for stress-related anxiety disorders.
A potent, synthetic cannabinoid was radiolabeled and used to characterize and precisely localize cannabinoid receptors in slide-mounted sections of rat brain and pituitary. Assay conditions for 3H-CP55,940 binding in Tris-HCl buffer with 5% BSA were optimized, association and dissociation rate constants determined, and the equilibrium dissociation constant (Kd) calculated (21 nM by liquid scintillation counting, 5.2 nM by quantitative autoradiography). The results of competition studies, using several synthetic cannabinoids, add to prior data showing enantioselectivity of binding and correlation of in vitro potencies with potencies in biological assays of cannabinoid actions. Inhibition of binding by guanine nucleotides was selective and profound: Nonhydrolyzable analogs of GTP and GDP inhibited binding by greater than 90%, and GMP and the nonhydrolyzable ATP analog showed no inhibition. Autoradiography showed great heterogeneity of binding in patterns of labeling that closely conform to cytoarchitectural and functional domains. Very dense 3H-CP55,940 binding is localized to the basal ganglia (lateral caudate-putamen, globus pallidus, entopeduncular nucleus, substantia nigra pars reticulata), cerebellar molecular layer, innermost layers of the olfactory bulb, and portions of the hippocampal formation (CA3 and dentate gyrus molecular layer). Moderately dense binding is found throughout the remaining forebrain. Sparse binding characterizes the brain stem and spinal cord. Densitometry confirmed the quantitative heterogeneity of cannabinoid receptors (10 nM 3H-CP55,940 binding ranged in density from 6.3 pmol/mg protein in the substantia nigra pars reticulata to 0.15 pmol/mg protein in the anterior lobe of the pituitary). The results suggest that the presently characterized cannabinoid receptor mediates physiological and behavioral effects of natural and synthetic cannabinoids, because it is strongly coupled to guanine nucleotide regulatory proteins and is discretely localized to cortical, basal ganglia, and cerebellar structures involved with cognition and movement.
We have developed a general strategy and a versatile computer program for analysis of data from ligand-binding experiments (e.g., radioreceptor assay systems for hormones, neurotransmitters, drugs). This method provides optimal (weighted least squares) estimates of “binding parameters” (affinity constants, binding capacities, nonspecific binding) for any number of ligands reacting simultaneously with any number of receptors. This approach provides two major advantages compared with other available methods: (i): It uses an exact mathematical model of the ligand-binding system, thereby avoiding the possible biases introduced by several commonly used approximations. (ii) It uses a statistically valid, appropriately weighted least-squares curve-fitting algorithm with objective measurement of goodness of fit, thereby avoiding the subjective graphical or simplified statistical methods which may introduce bias. Additional important features include the following. (i) The level of nonspecific binding is regarded as an unknown parameter, subject to uncertainty, which must be estimated simultaneously with other parameters of the system by appropriate statistical methods. This approach provides a more accurate and precise estimate of the parameters and their standard errors. (ii) Selected parameters can be forced to share a common value, or be fixed at any desired constant value. This feature facilitates hypothesis testing by appropriate statistical methods e.g., testing whether a particular experimental manipulation results in a change in affinity (K), binding capacity (R), or both parameters. (iii) One can combine results from multiple experiments by introduction of explicit scaling or “correction” factors which compensate for the commonly observed large degree of between-experiment variation of the overall binding capacity (Bmax) while other properties of the system (e.g., K values, relative binding capacities for high- and low-affinity sites) are highly reproducible. (iv) One can characterize complex cross-reacting systems involving any number of ligands reacting simultaneously with any number of binding sites. This enables one to pool results from several curves obtained using several different ligands.
Erucamide (13-docosenamide) was found to be the major bovine mesentery angiogenic lipid as assessed by chorioallantoic membrane (CAM) assay. Two micrograms of this lipid caused angiogenesis in the assay. Angiogenic activity of this naturally occurring lipid was also found by rat corneal micropocket and mouse dorsal air-sac assays. Specificity of the chemical structure which elicited activity was low, however. The mechanism of angiogenic activity is unknown and this lipid does not promote proliferation of endothelial cells or induce inflammatory effects.