Cannabinoid receptor stimulation is anti-inflammatory and improves memory in old rats.

Department of Psychology, Psychology Building, Ohio State University, Columbus, OH 43210, USA.
Neurobiology of aging (Impact Factor: 5.94). 07/2007; 29(12):1894-901. DOI: 10.1016/j.neurobiolaging.2007.04.028
Source: PubMed

ABSTRACT The number of activated microglia increase during normal aging. Stimulation of endocannabinoid receptors can reduce the number of activated microglia, particularly in the hippocampus, of young rats infused chronically with lipopolysaccharide (LPS). In the current study we demonstrate that endocannabinoid receptor stimulation by administration of WIN-55212-2 (2mg/kg day) can reduce the number of activated microglia in hippocampus of aged rats and attenuate the spatial memory impairment in the water pool task. Our results suggest that the action of WIN-55212-2 does not depend upon a direct effect upon microglia or astrocytes but is dependent upon stimulation of neuronal cannabinoid receptors. Aging significantly reduced cannabinoid type 1 receptor binding but had no effect on cannabinoid receptor protein levels. Stimulation of cannabinoid receptors may provide clinical benefits in age-related diseases that are associated with brain inflammation, such as Alzheimer's disease.

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    ABSTRACT: Background/Aims: The activation of cannabinoid receptor 2 (CB2) has the beneficial effect of reducing neuroinflammatory response in the treatment of Alzheimer's disease (AD) and is suggested to trigger the peroxisome proliferator-activated receptor-γ (PPARγ) pathway; agonists of both receptors improve AD. Recently, the plant metabolite β-caryophyllene was shown to selectively bind to CB2 receptor and act as a full agonist. Methods: In this study, we examined the anti-inflammatory effect of β-caryophyllene in a transgenic APP/PS1 AD model and analyzed whether this effect was mediated by CB2 and PPARγ. Results: β-Caryophyllene, given orally, prevented cognitive impairment in APP/PS1 mice, and this positive cognitive effect was associated with reduced β-amyloid burden in both the hippocampus and the cerebral cortex. Moreover, β-caryophyllene reduced astrogliosis and microglial activation as well as the levels of COX-2 protein and the mRNA levels of the proinflammatory cytokines tumor necrosis factor-α and interleukin-1β in the cerebral cortex. The use of the CB2 antagonist AM630 or the PPARγ antagonist GW9662 significantly reversed the protective effects of β-caryophyllene on APP/PS1 mice. Conclusion: These results demonstrate that the anti-inflammatory effect of the sesquiterpene β-caryophyllene involves CB2 receptor activation and the PPARγ pathway and suggest β-caryophyllene as an attractive molecule for the development of new drugs with therapeutic potential for the treatment of AD. © 2014 S. Karger AG, Basel.
    Pharmacology 08/2014; 94(1-2):1-12. DOI:10.1159/000362689 · 1.58 Impact Factor
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    ABSTRACT: In our previous studies, we found that a single ultralow dose of tetrahydrocannabinol (THC; 0.002 mg/kg, three to four orders of magnitude lower than the conventional doses) protects the brain from different insults that cause cognitive deficits. Because various insults may trigger a neuroinflammatory response that leads to secondary damage to the brain, the current study tested whether this extremely low dose of THC could protect the brain from inflammation-induced cognitive deficits. Mice received a single injection of THC (0.002 mg/kg) 48 hr before or 1–7 days after treatment with lipopolysccharide (LPS; 10 mg/kg) and were examined with the object recognition test 3 weeks later. LPS caused long-lasting cognitive deficits, whereas the application of THC before or after LPS protected the mice from this LPS-induced damage. The protective effect of THC was blocked by the cannabinoid (CB) 1 receptor antagonist SR14176A but not by the CB2 receptor antagonist SR141528 and was mimicked by the CB1 agonist ACEA but not by the CB2 agonist HU308. The protective effect of THC was also blocked by pretreatment with GW9662, indicating the involvement of peroxisome proliferator-activated receptor-γ. Biochemical examination of the brain revealed a long-term (at least 7 weeks) elevation of the prostaglandin-producing enzyme cyclooxygenase-2 in the hippocampus and in the frontal cortex following the injection of LPS. Pretreatment with the extremely low dose of THC tended to attenuate this elevation. Our results suggest that an ultralow dose of THC that lacks any psychotrophic activity protects the brain from neuroinflammation-induced cognitive damage and might be used as an effective drug for the treatment of neuroinflammatory conditions, including neurodegenerative diseases. © 2014 Wiley Periodicals, Inc.
    Journal of Neuroscience Research 07/2014; 92(12). DOI:10.1002/jnr.23452 · 2.73 Impact Factor


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May 28, 2014