The motor-stimulating effect of natural motilin on the lower esophageal sphincter fundus, antrum and duodenum in dogs.

Natural motilin was investigated for its effect on gastrointestinal motor activity in anesthetized dogs. In doses starting from 10 ng/kg as single injection and 100 ng/kg-h as intravenous infusion, motilin induced phasic pressure changes in the lower esophageal sphincter (LES) and in the lumen of the fundus, antrum, and duodenum. Tachyphylaxis was seen in 6 out of 10 dogs. Motilin had no effect on isolated muscle strip preparations of the LES, fundus, antrum, and duodenum in this species.