anandamide and Muscle-Spasticity

The endocannabinoid system (ECS) is involved in the pathophysiology of multiple sclerosis (MS), and relief from pain and spasticity has been reported in MS patients self-medicating with marijuana. A cannabis-based medication containing Delta(9)-tetrahydrocannabinol and cannabidiol (Sativex) has been approved in some countries for the treatment of MS-associated pain. The effects of this pharmaceutical preparation on other clinically relevant aspects of MS pathophysiology, however, are still unclear. In 20 MS patients, we measured the effects of Sativex on clinically measured spasticity and on neurophysiological and laboratory parameters that correlate with spasticity severity or with the modulation of the ECS. Sativex failed to affect spasticity and stretch reflex excitability. This compound also failed to affect the synthesis and the degradation of the endocannabinoid anandamide, as well as the expression of both CB1 and CB2 cannabinoid receptors in various subpopulations of peripheral lymphocytes.

Topics: Adult; Arachidonic Acids; Cannabidiol; Cannabinoids; Dronabinol; Drug Combinations; Endocannabinoids; Female; Humans; Lymphocytes; Male; Middle Aged; Multiple Sclerosis; Muscle Spasticity; Pain; Plant Extracts; Polyunsaturated Alkamides; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Reflex, Stretch; Treatment Outcome; Young Adult

It has been previously shown that CB1 cannabinoid receptor agonism using cannabis extracts alleviates spasticity in both a mouse experimental autoimmune encephalomyelitis (EAE) model and multiple sclerosis (MS) in humans. However, this action can be associated with dose-limiting side effects.. We hypothesised that blockade of anandamide (endocannabinoid) degradation would inhibit spasticity, whilst avoiding overt cannabimimetic effects.. Spasticity eventually developed following the induction of EAE in either wild-type or congenic fatty acid amide hydrolase (FAAH)-deficient Biozzi ABH mice. These animals were treated with a variety of different FAAH inhibitors and the effect on the degree of limb stiffness was assessed using a strain gauge.. Control of spasticity was achieved using FAAH inhibitors CAY100400, CAY100402 and URB597, which was sustained following repeated administrations. Therapeutic activity occurred in the absence of overt cannabimimetic effects. Importantly, the therapeutic value of the target could be definitively validated as the treatment activity was lost in FAAH-deficient mice. Spasticity was also controlled by a selective monoacyl glycerol lipase inhibitor, JZL184.. This study demonstrates definitively that FAAH inhibitors provide a new class of anti-spastic agents that may have utility in treating spasticity in MS and avoid the dose-limiting side effects associated with cannabis use.

Topics: Amidohydrolases; Animals; Arachidonic Acids; Brain; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Endocannabinoids; Enzyme Inhibitors; Female; Male; Mice; Mice, Biozzi; Mice, Knockout; Molecular Targeted Therapy; Monoacylglycerol Lipases; Muscle Spasticity; Muscle, Skeletal; Polyunsaturated Alkamides; Time Factors

We previously reported that the compound O-2093 is a selective inhibitor of the reuptake of the endocannabinoid anandamide (AEA). We have now re-examined the activity of O-2093 in vivo and synthesized four structural analogs (O-2247, O-2248, O-3246, and O-3262), whose activity was assessed in: (a) binding assays carried out with membranes from cells overexpressing the human CB(1) and CB(2) receptors; (b) assays of transient receptor potential of the vanilloid type-1 (TRPV1) channel functional activity (measurement of [Ca(2+)](i)); (c) [(14)C]AEA cellular uptake and hydrolysis assays in rat basophilic leukaemia (RBL-2H3) cells; (d) the mouse 'tetrad' tests (analgesia on a hot plate, immobility on a 'ring', rectal hypothermia and hypolocomotion in an open field); and (e) the limb spasticity test in chronic relapsing experimental allergic encephalomyelitis (CREAE) mice, a model of multiple sclerosis (MS). O-2093, either synthesized by us or commercially available, was inactive in the 'tetrad' up to a 20 mg kg(-1) dose (i.v.). Like O-2093, the other four compounds exhibited low affinity in CB(1) (K(i) from 1.3 to >10 microM) and CB(2) binding assays (1.310 microM), very low potency as fatty acid amide hydrolase (FAAH) inhibitors (IC(50)>25 microM) and were inactive in the 'tetrad' up to a 30 mg kg(-1) dose (i.v.). While O-2247 and O-2248 were poor inhibitors of [(14)C]AEA cellular uptake (IC(50)>40 microM), O-3246 and O-3262 were quite potent in this assay. O-3246, which exhibits only a very subtle structural difference with O-2093, is the most potent inhibitor of AEA uptake reported in vitro under our experimental conditions (IC(50)=1.4 microM) and is 12-fold more potent than O-2093. When injected intravenously O-3246 and O-3262, again like O-2093 and unlike O-2247 and O-2248, significantly inhibited limb spasticity in mice with CREAE. These data confirm the potential utility of selective AEA uptake inhibitors as anti-spasticity drugs in MS and, given the very subtle chemical differences between potent and weak inhibitors of uptake, support further the existence of a specific mechanism for this process.

Topics: Animals; Arachidonic Acids; Cell Line; Disease Models, Animal; Endocannabinoids; Mice; Multiple Sclerosis; Muscle Spasticity; Neuromuscular Blocking Agents; Polyunsaturated Alkamides; Rats