Role of endocannabinoid system in mental diseases.

“In the last decade, a large number of studies using Delta9-tetrahydrocannabinol (THC), the main active principle derivative of the marijuana plant, or cannabinoid synthetic derivatives have substantially contributed to advance the understanding of the pharmacology and neurobiological mechanisms produced by cannabinoid receptor activation.

 Cannabis has been historically used to relieve some of the symptoms associated with central nervous system disorders. Nowadays, there are anecdotal evidences for the use of cannabis in many patients suffering from multiple sclerosis or chronic pain. Following the historical reports of the use of cannabis for medicinal purposes, recent research has highlighted the potential of cannabinoids to treat a wide variety of clinical disorders. Some of these disorders that are being investigated are pain, motor dysfunctions or psychiatric illness…

 Considering that cannabis or cannabinoid pharmaceutical preparations may no longer be exclusively recreational drugs but may also present potential therapeutic uses, it has become of great interest to analyze the neurobiological and behavioral consequences of their administration. This review attempts to link current understanding of the basic neurobiology of the endocannabinoid system to novel opportunities for therapeutic intervention and its effects on the central nervous system.”

http://www.ncbi.nlm.nih.gov/pubmed/15325960

Cannabinoid-related agents in the treatment of anxiety disorders: current knowledge and future perspectives.

“Rich evidence has shown that cannabis products exert a broad gamut of effects on emotional regulation. The main psychoactive ingredient of hemp, Δ9-tetrahydrocannabinol (THC), and its synthetic cannabinoid analogs have been reported to either attenuate or exacerbate anxiety and fear-related behaviors in humans and experimental animals. The heterogeneity of cannabis-induced psychological outcomes reflects a complex network of molecular interactions between the key neurobiological substrates of anxiety and fear and the endogenous cannabinoid system, mainly consisting of the arachidonic acid derivatives anandamide and 2-arachidonoylglycerol (2-AG) and two receptors, respectively termed CB1 and CB2. The high degree of interindividual variability in the responses to cannabis is contributed by a wide spectrum of factors, including genetic and environmental determinants, as well as differences in the relative concentrations of THC and other alkaloids (such as cannabidiol) within the plant itself.

The present article reviews the currently available knowledge on the herbal, synthetic and endogenous cannabinoids with respect to the modulation of anxiety responses, and highlights the challenges that should be overcome to harness the therapeutic potential of some of these compounds, all the while limiting the side effects associated with cannabis consumption. In addition the article presents some promising patents on cannabinoid-related agents.”

http://www.ncbi.nlm.nih.gov/pubmed/22280339

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

“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

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

“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

Involvement of the opioid system in the anxiolytic-like effects induced by Delta(9)-tetrahydrocannabinol.

Recent studies have shown that several pharmacological actions induced by cannabinoids, including antinociception and reward, involve the participation of the endogenous opioid system. The present study was designed to examine the possible involvement of the different opioid receptors in the anxiolytic-like responses induced by Delta(9)-tetrahydrocannabinol (THC)…

The administration of a low dose of THC produced clear anxiolytic-like responses…

CONCLUSIONS:

These results demonstrate that the endogenous opioid system is involved in the regulation of anxiety-like behaviour by cannabinoids and provide new findings to clarify further the interaction between these two neuronal systems.”

http://www.ncbi.nlm.nih.gov/pubmed/12185408

Inhibition of endocannabinoid catabolic enzymes elicits anxiolytic-like effects in the marble burying assay

“Cannabinoids have long been shown to have a range of potential therapeutic effects, including antiemetic actions, analgesia, and anxiolysis. These data indicate that elevation of AEA or 2-AG reduces marble burying behavior and suggest that their catabolic enzymes represent potential targets for the development of new classes of pharmacotherapeutics to treat anxiety-related disorders.

Marijuana is commonly smoked to reduce feelings of stress and anxiety… much interest has been generated by the discovery of the endogenous cannabinoid (i.e. endocannabinoid; eCB) system as a source of targets for the development of new therapeutic treatments of a range of ailments including anxiety and depression…”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3034086/

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

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

A role for cannabinoid CB1 receptors in mood and anxiety disorders.

“Mood and anxiety disorders, the most prevalent of the psychiatric disorders, cause immeasurable suffering worldwide. Despite impressive advances in pharmacological therapies, improvements in efficacy and side-effect profiles are needed. The present literature review examines the role that the endocannabinoid system may play in these disorders and the potential value of targeting this system in the search for novel and improved medications.

Cannabis and its major psychoactive component (-)-trans-delta9-tetrahydrocannabinol, have profound effects on mood and can modulate anxiety and mood states. Cannabinoid receptors and other protein targets in the central nervous system (CNS) that modulate endocannabinoid function have been described. The discovery of selective modulators of some of these sites that increase or decrease endocannabinoid neurotransmission, primarily through the most prominent of the cannabinoid receptors in the CNS, the CB1 receptors, combined with transgenic mouse technology, has enabled detailed investigations into the role of these CNS sites in the regulation of mood and anxiety states. Although data point to the involvement of the endocannabinoid system in anxiety states, the pharmacological evidence seems contradictory: both anxiolytic- and anxiogenic-like effects have been reported with both endocannabinoid neurotransmission enhancers and blockers.

Due to advances in the development of selective compounds directed at the CB1 receptors, significant progress has been made on this target. Recent biochemical and behavioural findings have demonstrated that blockade of CB1 receptors engenders antidepressant-like neurochemical changes (increases in extracellular levels of monoamines in cortical but not subcortical brain regions) and behavioural effects consistent with antidepressant/antistress activity in rodents.”

http://www.ncbi.nlm.nih.gov/pubmed/16148437