Tag Archives: cannabinoid receptors

Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects.

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“Cannabis (marijuana, hashish, or cannabinoids) has been used for medical and recreational purposes for many centuries and is likely the only medicine or illicit drug that has constantly evoked tremendous interest or controversy within both the public domain and medical research. Cannabinoids appear to be able to modulate pain, nausea, vomiting, epilepsy, ischemic stroke, cerebral trauma, multiple sclerosis, tumors, and other disorders in humans and/or animals.

Cannabis acts on 2 types of cannabinoid receptors, the CB1 and CB2 receptors, which are distributed mainly in the brain and immune system, respectively. In the brain, CB1 receptors are also targeted by endogenous cannabinoids (i.e., endocannabinoids) such as anandamide (AEA), 2-arachidonylglycerol, and arachidonylethanolamide…

…since adult hippocampal neurogenesis is suppressed following chronic administration of opiates, alcohol, nicotine, and cocaine, the present study suggests that cannabinoids are the only illicit drug that can promote adult hippocampal neurogenesis following chronic administration…

Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects.”  

https://www.jci.org/articles/view/25509

“University Of Saskatchewan Research Suggests Marijuana Analogue Stimulates Brain Cell Growth”  http://www.sciencedaily.com/releases/2005/10/051016083817.htm

Cannabinoid effects on anxiety-related behaviours and hypothalamic neurotransmitters.

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“The aim of the present study was to examine the effects of the cannabinoid agonist CP 55,940 and the antagonist SR 141716A, alone and in combination, on rat exploratory and anxiety-like behaviour in the holeboard and elevated plus-maze tests. A further aim was to evaluate the effects of these treatments on hypothalamic neurotransmitters. Animals treated with CP 55,940 doses of 0.125 and 0.1 mg/kg exhibited less exploration and an increase in anxiety-like behaviour accompanied by great motor inhibition. No hypoactivity was seen at 0.075 mg/kg dosage, but anxiety and neophobic responses persisted, indicating independent and specific effects. Motor activity effects induced by CP 55,940 were reversed by pretreatment with SR 141716A (3 mg/kg). Surprisingly, when administered on its own, the antagonist also induced a reduction in exploratory parameters and an increase in anxiety-like responses. These apparently similar effects might be caused by different neural mechanisms. Finally, CP 55,940 increased hypothalamic dopamine and serotonin levels. These increases might be involved in the activation of the hypothalamic-pituitary-adrenal axis described for cannabinoids.”

http://www.ncbi.nlm.nih.gov/pubmed/11566149

Cannabinoid type 1 receptors and transient receptor potential vanilloid type 1 channels in fear and anxiety-two sides of one coin?

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“The transient receptor potential vanilloid type 1 channel (TRPV1; originally vanilloid receptor VR1) is activated in peripheral terminals of nociceptive fibers by noxious heat, low pH, and natural products such as capsaicin, the pungent ingredient of red-hot chilli peppers. Evidence has been accumulating that TRPV1 is expressed also in the brain, where it seems to be involved in antinociception, locomotor control, and regulation of affective behaviors. This ion channel might be activated by arachidonoyl ethanolamide (anandamide), the endogenous agonist of the cannabinoid type 1 (CB(1)) receptor. However, while CB(1) activation leads to a decrease in intracellular calcium and attenuation of synaptic transmission, anandamide binding to TRPV1 results in elevated calcium levels and potentiated synaptic transmission. This suggests a tripartite regulatory system with antagonistic effects of CB(1) and TRPV1, which are tied together by the same endogenous ligand. Such a system may have important implication for the modulation of behavioral responses. The present commentary elaborates on this interplay between CB(1) receptors and TRPV1 channels in the context of fear- and anxiety-related behaviors.”

http://www.ncbi.nlm.nih.gov/pubmed/21906661

Central side-effects of therapies based on CB1 cannabinoid receptor agonists and antagonists: focus on anxiety and depression.

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“Both agonists (e.g. Delta(9)-tetrahydrocannabinol, nabilone) and antagonists (e.g. rimonabant, taranabant) of the cannabinoid type-1 (CB(1)) receptor have been explored as therapeutic agents in diverse fields of medicine such as pain management and obesity with associated metabolic dysregulation, respectively. CB(1) receptors are widely distributed in the central nervous system and are involved in the modulation of emotion, stress and habituation responses, behaviours that are thought to be dysregulated in human psychiatric disorders. Accordingly, CB(1) receptor activation may, in some cases, precipitate episodes of psychosis and panic, while its inhibition may lead to behaviours reminiscent of depression and anxiety-related disorders. The present review discusses these side-effects, which have to be taken into account in the therapeutic exploitation of the endocannabinoid system.”

http://www.ncbi.nlm.nih.gov/pubmed/19285266

Impaired action of anxiolytic drugs in mice deficient in cannabinoid CB1 receptors.

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“The role of cannabinoid CB(1) receptors in the action of anxiolytics was examined. Deletion of CB(1) receptors resulted in increased anxiety-like behaviours… Our findings reveal that CB(1) receptors are involved in the regulation of emotional responses, and play a pivotal role in the action mechanism of anxiolytics. They suggest that alterations in the functional activity of the CB(1) receptor may be related to the emergence of anxiety disorders, and may affect treatment with anxiolytics.”

http://www.ncbi.nlm.nih.gov/pubmed/15081793

Effects of the cannabinoid receptor ligands on anxiety-related effects of d-amphetamine and nicotine in the mouse elevated plus maze test.

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“The purpose of the experiments was to examine the anxiety-related effects of d-amphetamine and nicotine, and the possible involvement of the endocannabinoid system…

These results provide evidence that the endogenous cannabinoid system is involved in the anxiety-related responses to d-amphetamine and/or nicotine.”

http://www.ncbi.nlm.nih.gov/pubmed/19617654

Randomised, double-blind, placebo-controlled trial to assess the potential of cannabinoid receptor stimulation in the treatment of dystonia.

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“Cannabis may have medicinal uses in a variety of diseases. The neural mechanisms underlying dystonia involve abnormalities within the basal ganglia-in particular, overactivity of the lateral globus pallidus (GPl). Cannabinoid receptors are located presynaptically on GABA terminals within the GPi, where their activation reduces GABA reuptake. Cannabinoid receptor stimulation may thus reduce overactivity of the GPl and thereby reduce dystonia. A double-blind, randomised, placebo-controlled, crossover study using the synthetic cannabinoid receptor agonist nabilone in patients with generalised and segmental primary dystonia showed no significant reduction in dystonia following treatment with nabilone.”

http://www.ncbi.nlm.nih.gov/pubmed/11835452

Anandamide hydrolysis: a new target for anti-anxiety drugs?

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“The major psychoactive constituent of cannabis, Delta(9)-tetrahydrocannabinol, affects emotional states in humans and laboratory animals by activating brain cannabinoid receptors. A primary endogenous ligand of these receptors is anandamide, the amide of arachidonic acid with ethanolamine. Anandamide is released in selected regions of the brain and is deactivated through a two-step process consisting of transport into cells followed by intracellular hydrolysis. Pharmacological blockade of the enzyme fatty acid amide hydrolase (FAAH), which is responsible for intracellular anandamide degradation, produces anxiolytic-like effects in rats without causing the wide spectrum of behavioral responses typical of direct-acting cannabinoid agonists. These findings suggest that anandamide contributes to the regulation of emotion and anxiety, and that FAAH might be the target for a novel class of anxiolytic drugs.”

http://www.ncbi.nlm.nih.gov/pubmed/14604824

Cannabinoid CB1 receptors of the rat central amygdala mediate anxiety-like behavior: interaction with the opioid system.

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“Cannabinoids, which are the active compounds of marijuana, produce some pharmacological effects similar to the opioids. In addition, there are functional interactions between the cannabinoid and opioid systems. In this study, we investigated the effects of intraperitoneal (i.p.) injection of opioid drugs on responses induced by intracentral amygdala (intra-CeA) microinjection of cannabinoid CB1 receptor agents in rats, using the elevated plus maze test of anxiety…

 In conclusion, the results may indicate an anxiolytic-like effect for cannabinoid CB1 receptors of the CeA and the existence of an interaction between the cannabinoid and the opioid systems in the modulation of anxiety.” 

http://www.ncbi.nlm.nih.gov/pubmed/18797248

Activation of cannabinoid CB1 receptors in the dorsolateral periaqueductal gray induces anxiolytic effects in rats submitted to the Vogel conflict test.

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“Activation of cannabinoid CB(1) receptors in the dorsolateral periaqueductal gray induces anxiolytic-like effects in the elevated plus maze. The aim of this work was to verify if facilitation of endocannabinoid-mediated neurotransmission in this region would also produce anxiolytic-like effects in another model of anxiety, the Vogel conflict test…

The results give further support to the proposal that facilitation of CB(1) receptor-mediated endocannabinoid neurotransmission in the dorsolateral periaqueductal gray modulates defensive responses.”

http://www.ncbi.nlm.nih.gov/pubmed/18691568