Tachykinins stimulate acid and pepsinogen secretion in the isolated porcine stomach.

Abstract

The precise role of tachykinins in regulation of acid and pepsinogen secretion has not been established. Tachykininergic effects on acid and pepsinogen secretion could be mediated either directly in the proximal stomach or through other indirect mechanisms, i.e. gastrin secretion. We studied the effects of the two tachykinins, substance P and neurokinin A, and of capsaicin, on acid and pepsinogen output, in isolated porcine non-antral stomach preparation. The release of substance P and neurokinin A was studied during electrical stimulation of the vagal nerves, and during capsaicin infusion. Substance P infusion (10-8 M) increased acid secretion from 30 +/- 8 to 68 +/- 17 fmol min-1 (n=6, P < 0.05) and pepsinogen output from 46 +/- 12 to 160 +/- 47 units of pepsin min-1 (n=9, P < 0.05). Neurokinin A also stimulated both acid and pepsinogen secretion, while capsaicin had no effect on either parameter. Electrical stimulation of the vagal nerves increased the release of both peptides. We conclude that tachykinins may be involved in regulation of acid and pepsinogen secretion.