Effect of glucagon on the motility of esophageal smooth muscle.

The functions of glucagon were studied experimentally and clinically. It was found that glucagon (2 x 10(-6)g/ml) could not induce any demonstrable changes in the longitudinal contraction and tonicity of the isolated muscle of the lower esophageal body in 4 rats, nor could cause (0.2 mg iv) significant changes in swallow motility of the esophagus and lower esophageal sphincter (LES) (the esophageal barium transit time, the largest esophageal caliber, the angle of esophageal contraction, the largest LES caliber, and the amount of barium retention at LES) in 6 volunteers under serial-radiography but it (0.2 mg iv) could cause hypomotility of the stomach and duodenum in 19 volunteers. No obvious side-effects were found in 20 volunteers. The recent experimental evidences have suggested that the inhibitory effect of glucagon on the motility of the smooth muscle of the alimentary tract may not be due to its direct action on the receptor, but to its interference with intramural cholinergic neuronal transmission.