Proof of a pyloro-oxyntic reflex for stimulation of acid secretion.

Abstract

In 7 dogs with innervated antral pouch, gastric fistula, and Heidenhain pouch, acid secretion and serum gastrin (radioimmunoassay) were measured in response to distention of the antral pouch with 0.1 m NaHCO 3 or 0.1 m HCl at 0-, 10-, 20-, 30-, and 40-cm pressure. Distention with 0.1 ivt NaHCO 3 caused graded increases in serum gastrin and in acid output from both the gastric fistula and Heidenhain pouch. Acidification of the antral pouch abolished gastrin release and acid secretion from the Heidenhain pouch in response to distention, but did not abolish acid secretion from the gastric fistula. These results indicated that antral distention causes acid secretion by at least two mechanisms, only one of which is gastrin-dependent. Proof that the gastrin-independent mechanism is a pyloro-oxyntic reflex was obtained by showing that vagal denervation of the antral pouch completely abolished the response of the gastric fistula to distention of the antral pouch with acid. In addition to abolishing the pyloro-oxyntic reflex, antral vagal denervation also had these effects: (a) decreased the increment in serum gastrin caused by alkaline antral distention, and (b) increased the amount of acid secreted in response to any given increment in serum gastrin.