Inhibitory effect of cannabinoid agonists on gastric emptying in the rat

We have studied the effect of WIN 55,212-2 (a psychoactive cannabinoid agon ist), cannabinol (a non-psychoactive cannabinoid agonist), SR141716A, a can nabinoid CB1 antagonist, and SR144528, a cannabinoid CB2 antagonist, on gas tric emptying in the rat. WIN 55,212-2 (0.1-5 mg/kg, i.p.) and cannabinol ( 0.1-25 mg/kg, i.p.) dose-dependently delayed gastric emptying while SR14171 6A (1 mg/kg and 5 mg/kg) and SR144528 (1 mg/kg) were without effect. SR1417 16A (1 mg/kg), but not SR144528 (1 mg/kg), counteracted the inhibitory effe ct of the two cannabinoid agonists. These results suggest that cannabinoid agonists delay gastric emptying through activation of cannabinoid CB1 recep tors, while the endogenous cannabinoid system does not seem to modulate gas tric motility.