Effects of aspirin and prostaglandin E2 on interdigestive motility complex and duodenogastric reflux in man.

Both increased duodenogastric reflux and chronic aspirin ingestion are associated with the development of gastric ulcers in man. Animal studies suggest aspirin increases duodenogastric reflux. Prostaglandin E2 protects gastric mucosa from the effects of many injurious agents and inhibits gastric motility, but its effect on duodenogastric reflux is unknown. We have studied the effects of aspirin and a synthetic derivative of prostaglandin E2 on duodenogastric reflux during fasting in six normal subjects, while concomitantly monitoring gastrointestinal motility by means of a perfused catheter system. We found that duodenogastric reflux (as measured by bile salt output in gastric aspirates) increased significantly (P less than 0.05) following both the prostaglandin E2 derivative and aspirin. This increase occurred in phases II and III of the interdigestive motility complex. Both drugs were associated with a significant reduction (P less than 0.05) in frequency and amplitude of antral contraction during phase II. Both drugs also induced a significant disruption (P less than 0.01) of phase III, increasing the number of complexes without an antral and duodenal component. These effects of aspirin may be one of the factors predisposing to the gastric mucosal damage associated with aspirin. The prostaglandin E2 derivative protects gastric mucosa by mechanisms other than reducing duodenogastric reflux and ameliorating the motility disturbances caused by aspirin.