In-vivo Modulation of Gastrointestinal Motility by Cannabinoid Drugs

Cannabinoid CB1 receptors have been detected in several peripheral neurons, including those of the myenteric plexus. Activation of myenteric (prejunctional located) cannabinoid CB1 receptors decreased intestinal motility induced by electrical stimulation in the isolated guinea-pig and human ileum. In-vivo studies have shown that cannabinoid receptor agonists decreased gastrointestinal motility through activation of cannabinoid CB1 receptors, while SR141716A, a cannabinoid CB1-receptor antagonist, increased intestinal motility. Both central and peripheral cannabinoid CB1 receptors could modulate upper gastrointestinal, but the effect of systemic (intraperitoneally injected) cannabinoid drugs was mediated by peripheral receptors. In addition, the potency of cannabinoid receptor agonists was increased during inflammatory diarrhoea.