Cannabinoids and intestinal motility: welcome to CB2 receptors.

Delta(9)-tetrahydrocannabinol (the active ingredient of marijuana), as well as endogenous and synthetic cannabinoids, exert many biological functions by activating two types of cannabinoid receptors, CB(1) receptors (expressed by central and peripheral neurons) and CB(2) receptors (that occur mainly in immune cells). Convincing evidence has accumulated in recent years that cannabinoids inhibit gastric and intestinal motility through activation of enteric CB(1) receptors. However, a report in this issue of British Journal of Pharmacology has highlighted the possibility that CB(2) receptors in the rat intestine could contribute to reducing the increase of intestinal motility induced by an endotoxic inflammation. By minimizing the adverse psychotropic effects associated with brain cannabinoid receptors, the CB(2) receptor represents a new molecular target for the treatment of motility disorders associated with intestinal inflammation.