Cannabis and Multiple Sclerosis

Cannabis sativa contains 60 or more cannabinoids,the most abundant of which are delta-9-tetrahydro-cannabinol (THC) and cannabidiol (CBD). Both of these have a pharmacology which suggests they may be useful in the relief of spasticity. The endogenous cannabinoids (anandamide,2-arachidonoyl glycerol [2-AG]) act primarily via specific cannabinoid receptors (CBr): CB1 receptors are predominantly distributed in the CNS; CB2 receptors are located both in the CNS and extensively in the periphery (especially the immune system). Both endogenous and exogenous cannabinoids have been shown to have a therapeutic effect in the animal models of MS spasticity, through effects primarily at the CB1r. However, it has also been shown that not all of their effects are mediated through the CB1r. The principal pharmacological effects of THC include analgesia, muscle relaxation, anti-emesis, appetite stimulation and psychoactivity. CBD has anticonvulsant, muscle relaxant, anxiolytic, neuroprotective, antioxidant and anti psychotic activity and has been shown to reduce the anxiogenic and psychoactive effects of THC. Nabiximols (Sativex; GW Pharma Ltd, Salisbury,UK) contains THC + CBD at a nearly 1:1 fixed ratio and is described as an endocannabinoid system modulator. It is derived from fully standardized chemotypes