[Effect of acetylcholine, histamine and serotonin on the myoelectrical activity of the stomach and small intestine in waking dogs].

Acetylcholine, histamine and serotonin injected intravenously to conscious dogs stimulated myoelectric activity in the distal part of the stomach more intensely than in the proximal one. Acetylcholine and serotonin were more powerful stimulators as regards the proximal part of the small intestine, while histamine as regards the distal part. It is suggested that selective action of the drugs might result from the proximodistal gradient of the physiologically active substances along the smooth muscles of the gastrointestinal tract.