“Fatty acid amide hydrolase (FAAH) and monoglyceride lipase (MGL) are hydrolytic enzymes which degrade the endogenous cannabinoids (endocannabinoids) N-arachidonoylethanolamine (anandamide, AEA) and 2-arachidonoylglycerol (2-AG), respectively. Endocannabinoids are an important class of lipid messenger molecules that are produced on demand in response to elevated intracellular calcium levels. They recognize and activate the cannabinoid CB(1) and CB(2) receptors, the molecular targets for Delta(9)-tetrahydrocannabinol (Delta(9)-THC) in marijuana evoking several beneficial therapeutic effects. However, in vivo the cannabimimetic effects of AEA and 2-AG remain weak owing to their rapid inactivation by FAAH and MGL, respectively. The inactivation of FAAH and MGL by specific enzyme inhibitors increases the levels of AEA and 2-AG, respectively, producing therapeutic effects such as pain relief and depression of anxiety.”
Tag Archives: endocannabinoids
Modulation of anxiety through blockade of anandamide hydrolysis.
“The psychoactive constituent of cannabis, Delta(9)-tetrahydrocannabinol, produces in humans subjective responses mediated by CB1 cannabinoid receptors, indicating that endogenous cannabinoids may contribute to the control of emotion. But the variable effects of Delta(9)-tetrahydrocannabinol obscure the interpretation of these results and limit the therapeutic potential of direct cannabinoid agonists. An alternative approach may be to develop drugs that amplify the effects of endogenous cannabinoids by preventing their inactivation. Here we describe a class of potent, selective and systemically active inhibitors of fatty acid amide hydrolase, the enzyme responsible for the degradation of the endogenous cannabinoid anandamide. Like clinically used anti-anxiety drugs, in rats the inhibitors exhibit benzodiazepine-like properties in the elevated zero-maze test and suppress isolation-induced vocalizations. These effects are accompanied by augmented brain levels of anandamide and are prevented by CB1 receptor blockade.
Our results indicate that anandamide participates in the modulation of emotional states and point to fatty acid amide hydrolase inhibition as an innovative approach to anti-anxiety therapy.”
Endocannabinoids mediate anxiolytic-like effect of acetaminophen via CB1 receptors.
“Acetaminophen (Paracetamol), a most commonly used antipyretic/analgesic agent, is metabolized to AM404 (N-arachidonoylphenolamine) that inhibits uptake and degradation of anandamide which is reported to mediate the analgesic action of acetaminophen via CB1 receptor. AM404 and anandamide are also reported to produce anxiolytic-like behavior. In view of the implication of endocannabinoids in the effect of acetaminophen, we contemplated that acetaminophen may have anxiolytic-like effect. Therefore, this possibility was tested by observing the effects of various doses of acetaminophen in mice on anxiety-related indices of Vogel conflict test and social interaction test. The results from both the tests indicated that acetaminophen (50, 100, or 200 mg/kg, i.p.) or anandamide (10 or 20 microg/mouse, i.c.v.) dose dependently elicited anxiolytic-like effect, that was comparable to diazepam (2 mg/kg, i.p.). Moreover, co-administration of sub-effective dose of acetaminophen (25 mg/kg, i.p.) and anandamide (5 microg/mouse, i.c.v) produced similar anxiolytic effect. Further, pre-treatment with AM251 (a CB1 receptor antagonist; 1 mg/kg, i.p.) antagonized the effects of acetaminophen and anandamide with no per se effect at 1 mg/kg dose, while anxiogenic effect was evident at a higher dose (5 mg/kg, i.p.). None of the treatment/s was found to induce any antinociceptive or locomotor impairment effects. In conclusion, the findings suggested that acetaminophen (50, 100, or 200 mg/kg, i.p.) exhibited dose dependent anxiolytic effect in mice and probably involved endocannabinoid-mediated mechanism in its effect.”
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…”
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.”
Acute stress increases circulating anandamide and other N-acylethanolamines in healthy humans.
“Stress plays an important role in psychiatric disorders, and preclinical evidence indicates that the central endocannabinoid system modulates endocrine and neuronal responses to stress. This study aimed to investigate the effect of acute stress on circulating concentrations of endocannabinoids (eCBs) in healthy humans…
…stress increased serum concentrations of AEA and the other NAEs immediately after the stress period…These results indicate that stress increases circulating NAEs in healthy human volunteers.
This finding supports a protective role for eCBs in anxiety. Further research is needed to elucidate the function of these lipid mediators, and to determine the mechanisms that regulate their appearance in the circulation.”
Endocannabinoid system and mood disorders: Priming a target for new therapies.
“The endocannabinoid system (ECS), comprising two G protein-coupled receptors (the cannabinoid receptors 1 and 2 [CB1 and CB2] for marijuana’s psychoactive principle ∆(9)-tetrahydrocannabinol [∆(9)-THC]), their endogenous small lipid ligands (namely anandamide [AEA] and 2-arachidonoylglycerol [2-AG], also known as endocannabinoids), and the proteins for endocannabinoid biosynthesis and degradation, has been suggested as a pro-homeostatic and pleiotropic signaling system activated in a time- and tissue-specific way during physiopathological conditions. In the brain activation of this system modulates the release of excitatory and inhibitory neurotransmitters and of cytokines from glial cells. As such, the ECS is strongly involved in neuropsychiatric disorders, particularly in affective disturbances such as anxiety and depression. It has been proposed that synthetic molecules that inhibit endocannabinoid degradation can exploit the selectivity of endocannabinoid action, thus activating cannabinoid receptors only in those tissues where there is perturbed endocannabinoid turnover due to the disorder, and avoiding the potential side effects of direct CB1 and CB2 activation. However, the realization that endocannabinoids, and AEA in particular, also act at other molecular targets, and that these mediators can be deactivated by redundant pathways, has recently led to question the efficacy of such approach, thus opening the way to new multi-target therapeutic strategies, and to the use of non-psychotropic cannabinoids, such as cannabidiol (CBD), which act via several parallel mechanisms, including indirect interactions with the ECS. The state of the art of the possible therapeutic use of endocannabinoid deactivation inhibitors and phytocannabinoids in mood disorders is discussed in this review article.”
The endocannabinoid system and Alzheimer’s disease.
“The importance of the role of the endocannabinoid system (ECS) in neurodegenerative diseases has grown during the past few years. Mostly because of the high density and wide distribution of cannabinoid receptors of the CB(1) type in the central nervous system (CNS), much research focused on the function(s) that these receptors might play in pathophysiological conditions.
Our current understanding, however, points to much diverse roles for this system. In particular, other elements of the ECS, such as the fatty acid amide hydrolase (FAAH) or the CB(2) cannabinoid receptor are now considered as promising pharmacological targets for some diseases and new cannabinoids have been incorporated as therapeutic tools.
Although still preliminary, recent reports suggest that the modulation of the ECS may constitute a novel approach for the treatment of Alzheimer’s disease (AD). Data obtained in vitro, as well as in animal models for this disease and in human samples seem to corroborate the notion that the activation of the ECS, through the use of agonists or by enhancing the endogenous cannabinoid tone, may induce beneficial effects on the evolution of this disease.”
Targeting the endocannabinoid system in Alzheimer’s disease.
“The endocannabinoid system is rapidly emerging as a potential drug target for a variety of immune-mediated central nervous system diseases. There is a growing body of evidence suggesting that endocannabinoid interventions may have particular relevance to Alzheimer’s disease. Here we present a review of endocannabinoid physiology, the evidence that underscores its utility as a potential target for intervention in Alzheimer’s disease, and suggest future pathways of research.
Inflammation and oxidative stress are generally accepted as a critical risk factor for the development of AD, and interventions such as cannabinoids that attenuate these risks without arresting microglial activity and have innate neuroprotective benefits are attractive as potential preventative treatments for AD.
There is a potential for the development of CB1 interventions, whether agonists or antagonists, with applications for a variety of cognitive disorders including neurodegenerative disorders and schizophrenia. The recent discovery of a CB1 receptor Positron Emission Tomography tracer for clinical use may provide the opportunity to evaluate the impact of the regional distribution of CB1 receptors in brain on domain-specific cognitive performance (memory, executive function, praxis) in healthy individuals. Additionally, if AD is a disease of overproduction of eCBs, this may be visualized in case-control CB1receptor binding studies.
The emerging data suggest that the eCB system is a potential target for immune and/or cognitive intervention in AD. A wealth of available chemical compounds capable of intervening in the eCB system at a variety of levels and the success with which these compounds have been used in animal models suggest the potential for human drug development. What is missing is a clear direction for that development based on a concise conceptualization of eCB system function in both health and in neurodegenerative and inflammatory conditions such as AD. Focused experiments are now required to move the field forward.”
The role of the endocannabinoid system in Alzheimer’s disease: facts and hypotheses.
“Unlike other neuroinflammatory disorders, like Parkinson’s disease, Huntington’s disease and multiple sclerosis, little is still known of the role of the endocannabinoid system in Alzheimer’s disease (AD). This is partly due to the poor availability of animal models that are really relevant to the human disease, and to the complexity of AD as compared to other neurological states. Nevertheless, the available data indicate that endocannabinoids are likely to play in this disorder a role similar to that suggested in other neurodegenerative diseases, that is, to represent an endogenous adaptive response aimed at counteracting both the neurochemical and inflammatory consequences of beta-amyloid-induced tau protein hyperactivity, possibly the most important underlying cause of AD.
Furthermore, plant and synthetic cannabinoids, and particularly the non-psychotropic cannabidiol, might also exert other, non-cannabinoid receptor-mediated protective effects, including, but not limited to, anti-oxidant actions. There is evidence, from in vivo studies on beta-amyloid-induced neurotoxicity, also for a possible causative role of endocannabinoids in the impairment in memory retention, which is typical of AD.
This might open the way to the use of cannabinoid receptor antagonists as therapeutic drugs for the treatment of cognitive deficits in the more advanced phases of this disorder. The scant, but nevertheless important literature on the regulation and role of the endocannabinoid system in AD, and on the potential treatment of this disorder with cannabinoids and endocannabinoid-based drugs, are discussed in this mini-review.”