Trimebutine at low concentrations (6 X 10(-9)-1.4 X 10(-8) M) slightly enhanced the twitch response of isolated guinea pig ileum induced by transmural stimulation. At high concentrations (2 X 10(-8)-2 X 10(-7) M), however, it inhibited the twitch response in a dose dependent manner. This inhibitory effect of trimebutine was reversed by naloxone (8.1 X 10(-9) M). These results suggest that trimebutine has an opiate-like action on the myenteric plexus.</p
