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

“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

Interaction between cannabinoid compounds and diazepam on anxiety-like behaviour of mice.

“Previous studies have suggested that cannabinoidergic system is involved in anxiety. However, a complete picture of cannabinoid association in the anxiety is still lacking. In the present study, we investigated the possible interaction between cannabinoidergic and GABAergic systems in the anxiety-like behaviour of mice…

 Taken together, the present study showed that co-administration of exogenous cannabinoids and diazepam produce additive or synergistic effect at different combinations. Moreover, it has been shown that enhancement of the function of endocannabinoids could increase the anxiolytic effect of diazepam.”

http://www.ncbi.nlm.nih.gov/pubmed/18096213

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

“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.

“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

The cannabinoid CB1 receptor is involved in the anxiolytic, sedative and amnesic actions of benzodiazepines.

“Previous studies in our laboratory showed that cannabinoid CB1 receptor knockout mice (CB1-/-) presented increased anxiety-like behaviours that did not respond to the anxiolytic actions of benzodiazepines. These results suggest that the pharmacological effects of benzodiazepines may involve the participation of cannabinoid CB1 receptors. Therefore, the purpose of this study was to examine the effects of alprazolam and the cannabinoid CB1 receptor antagonist…

Taken together, these findings revealed that cannabinoid CB1 receptor plays a pivotal role in the pharmacological actions of benzodiazepines. Furthermore, these results suggest that blockade of cannabinoid CB1 receptors may be useful in the treatment of patients with problems related to the consumption of benzodiazepines. Further clinical trials are needed to test this hypothesis.”

http://www.ncbi.nlm.nih.gov/pubmed/19825899

CB1 cannabinoid receptors mediate anxiolytic effects: convergent genetic and pharmacological evidence with CB1-specific agents.

“Cannabinoids are known to modulate GABAergic and glutamatergic transmission in cortical areas, the former via CB1 and the latter via a novel receptor. Pharmacological data demonstrate that several widely used cannabinoid ligands bind to both receptors, which may explain the inconsistencies in their behavioural effects. 

 In the present experiments, we studied the effects of the CB1 antagonist… and the cannabinoid agonist… in wild-type as well as in CB1 knockout mice… In wild types, the cannabinoid agonist… caused a decrease in anxiety-like behaviour, which was abolished by the CB1-selective antagonist…

 Our studies on the behavioural effects of the cannabinoid antagonist SR-141716A and the CB1 antagonist AM-251 show that the CB1 and the novel cannabinoid receptor mediate anxiolytic (anti-anxiety) and anxiogenic (anxiety) effects, respectively.

This suggests that agonists of the former, or antagonists of the latter, are promising new compounds in the pharmacotherapy of anxiety.”

http://www.ncbi.nlm.nih.gov/pubmed/15252281

Antagonism of cannabinoid 1 receptors reverses the anxiety-like behavior induced by central injections of corticotropin-releasing factor and cocaine withdrawal.

“The endocannabinoid (eCB) system is an important regulator of the stress response and mediates several stress-related behaviors, including anxiety. Despite anatomical evidence that eCBs interact with the principle stress peptide, corticotropin-releasing factor (CRF), few data exist that address functional interactions between these systems. Accordingly, we examined the effects of the CB1 receptor antagonist, AM251, on behavioral anxiety induced by (1) exogenous CRF, and (2) withdrawal from chronic cocaine exposure (mediated by CRF)… Our findings suggest that the anxiogenic effects of CRF and cocaine withdrawal are mediated, at least in part, by CB1 receptor transmission, and provide evidence in support of eCB-CRF interactions that are independent of the hypothalamic-pituitary-adrenal axis.”

http://www.ncbi.nlm.nih.gov/pubmed/21784132

Cat odour-induced anxiety–a study of the involvement of the endocannabinoid system.

“Recent evidence suggests the involvement of the endocannabinoid (EC) system in the regulation of anxiety.The aim of present work was to study the role of the EC system in cat odour-induced anxiety in rats… Exposure to cat odour induces anxiogenic-like effect on the behaviour in rats… Relation of predator odour-induced anxiety to the inhibition of the EC system in the amygdala and PAG is supported by behavioural studies where blockade of CB1 receptors by rimonabant induces anxiogenic-like action.”

http://www.ncbi.nlm.nih.gov/pubmed/17882402

Anti-Aversive Effects of Cannabidiol on Innate Fear-Induced Behaviors Evoked by an Ethological Model of Panic Attacks Based on a Prey vs the Wild Snake Epicrates cenchria crassus Confrontation Paradigm

“Research on the interaction between different compounds extracted from the plant Cannabis sativa (Cannabis) and the endocannabinoid system has revealed a series of ligands that selectively bind to cannabinoid receptors. The activation of this system causes a wide spectrum of responses, some of which could be potentially therapeutic. Recently, much attention has been given to cannabidiol (CBD), a major constituent of Cannabis that is unable to mimic all of the effects of the plant but has a wide range of pharmacological effects. In the elevated plus-maze, this drug produces an anxiolytic-like effect…

… attention has been given to the potential anxiolytic properties of cannabidiol, because of its complex actions on the endocannabinoid system together with its effects on other neurotransmitter systems. The aim of this study was to investigate the effects of cannabidiol on innate fear-related behaviors evoked by a prey vs predator paradigm…

These results show that cannabidiol modulates defensive behaviors evoked by the presence of threatening stimuli…

In summary, the data presented in this study suggest that the complex action of CBD on the endocannabinoid-mediated system, together with its putative effect on the serotonin-mediated system, could have a pivotal role in the regulation of emotional states and thus constitute a novel pharmacological target for anti-panic therapy.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3242302/

The anxiolytic-like effects of cannabidiol injected into the bed nucleus of the stria terminalis are mediated by 5-HT1A receptors.

“Cannabidiol (CBD) is a non-psychotomimetic compound from Cannabis sativa that induces anxiolytic-like effects in rodents and humans after systemic administration. Previous results from our group showed that CBD injection into the bed nucleus of the stria terminalis (BNST) attenuates conditioned aversive responses. The aim of this study was to further investigate the role of this region on the anxiolytic effects of the CBD. Moreover, considering that CBD can activate 5-HT1A receptors, we also verified a possible involvement of these receptors in those effects.

CONCLUSIONS:

These results give further support to the proposal that BNST is involved in the anxiolytic-like effects of CBD observed after systemic administration, probably by facilitating local 5-HT1A receptor-mediated neurotransmission.”

http://www.ncbi.nlm.nih.gov/pubmed/20945065