Cannabinoids for the control of experimental multiple sclerosis

Abstract

There have been numerous studies reporting that cannabinoids, both exogenous and endogenous, have a potential beneficial function during incidences of neurological damage. Using gene knockout mice and cannabinoid-selective agents, this study demonstrates the diverse actions of cannabinoids with a particular focus on experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis. The results presented here report on the action of stimulators of cannabinoid receptors in the nervous system (CNS) on; immune function, as a mechanism of suppressing autoimmune attack of the central nervous system, as agents to suppress neurodegenerative events leading to disease progression and as agents that can control signs of disease that occur as the consequences of autoimmune neurodegeneration such as spasticity. Tetrahydrocannabinol the psychoactive component in cannabis and the CB1 cannabinoid receptor appears to be central to many of the therapeutic actions of cannabis but also to the side-effect potential of cannabinoid drugs. This study reports on methods to avoid psychoactive side-effects of conventional brain-penetrant CB1 receptor agonists whilst exploiting the therapeutic potential of the cannabinoid system in order to control spasticity. This was achieved by targeting mechanisms of endocannabinoid degradation, particularly using fatty acid amide hydrolase inhibitors. Furthermore, this study also reports the development of novel cannabinoid compounds that are excluded from the brain and inhibit spasticity and also demonstrates the mechanism of exclusion of CNS-excluded cannabinoid CB1 receptor agonists. This study provides further evidence for the efficacy of cannabinoid compounds during an ongoing CNS disease and also their efficacy for treating the consequences of CNS autoimmune disease, which hopefully, will give additional impetus for further clinical investigations of cannabinoid agents in not only multiple sclerosis but also other neurodegenerative diseases of the CNS.