The Enterogastric Reflex.

Abstract

Numerous investigators have reported a delay in gastric evacuation as a result of placing acid, fat, gastric juice, etc., in the duodenum or other parts of the small intestine. The effect has generally been attributed to a reflex (the “Hirsch v. Mering reflex”) causing tonic contraction of the pyloric sphincter. However, two studies record inhibition of contractions of the pars pylorica following the introduction of acid 1 or fat 2 into the duodenum. Apparently both investigations were made upon the empty stomach, though Edelmann 2 observed inhibition of gastric contractions during secretion of gastric juice. There are no data in either report to prove that the phenomenon occurs in the full stomach or has any bearing on the mechanism of gastric evacuation.

We studied the effect of placing various substances in the duodenum while recording graphically the tone changes in the pyloric sphincter by means of the pressure tonometer, 3 and the contractions of the pars pylorica by means of a balloon placed in the pyloric canal. Observations were made before, during and after feeding. A balloon in the pyloric canal of the empty stomach registers contractions which are indistinguishable graphically from digestive peristalsis and are probably aroused by the presence of the balloon. We do not consider them hunger contractions. Dogs were used, some narcotized, others without anesthesia or narcosis. The latter were provided with gastric and duodenal fistulas fitted with cannulas.

HCl N/10 in the duodenum, inhibits the contractions of the pars pylorica in both the full and empty stomach. In the former the typical effect is decrease in force rather than cessation of contractions. The pyloric sphincter, after a momentary increase in tonus, is likewise relaxed and its rhythmic contractions are inhibited, roughly in proportion to the similar effect on the pars pylorica.