Effects of motilin and octapeptide of cholecystokinin on antral and duodenal myoelectric activity in the interdigestive state and during inhibition by secretin and gastric inhibitory polypeptide.

In conscious dogs prepared with gastric cannulae and antral and duodenal electrodes, intravenous administration of synthetic porcine motilin and CCK-OP in varying doses resulted in significant increases in the mean percent frequency of spike potentials on slow waves. Motilin was a more potent stimulant than CCK-OP. Motilin-stimulated spike potentials in both antrum and duodenum were significantly suppressed by either natural porcine secretin or synthetic porcine GIP. Secretin suppressed the spike potentials of the antrum stimulated by CCK-OP but not those of the duodenum. The spike potentials stimulated by CCK-OP could not be suppressed by GIP in the dosages employed.