Verapamil--a potent inhibitor of esophageal contractions in the baboon.

Verapamil, a calcium channel blocking agent, has been shown to be a potent inhibitor of smooth muscle contraction. We studied the effects of verapamil on lower esophageal sphincter pressure and esophageal peristalsis in 5 awake baboons. An infusion of verapamil (80 micrograms/kg . min) decreased amplitude of peristalsis by 63% in the smooth muscle segments of the esophagus but had no effect on striated muscle. Duration of peristaltic waves in the smooth muscle portion of the esophagus was also shortened, but there was no effect on velocity of the contraction wave. Lower esophageal sphincter pressure decreased by 74% during verapamil infusion. These studies suggest that verapamil or other calcium channel blocking agents may be of potential use in the treatment of esophageal motility disorders associated with increased pressure.