Figure 1.

Effect of the acute, intraperitoneal administration of different doses of the cannabinoid, WIN 55,212-2 (a), morphine (b), and loperamide (c) on time of whole gut transit in propulsive activity in CB₁^−/− and CB₁^+/+ mice. Time of whole gut transit indicated the time elapsing between the intragastric administration of the nonabsorbable coloured marker, carmine, and excretion of the first red fecal bolus. Each bar is the mean±s.e.m. of n=6–8 mice. ^*P<0.05 with respect to vehicle-treated mice of the same strain (Newman–Keuls test).