AJP - Regulatory, Integrative and Comparative Physiology, Vol 269, Issue 5 983-R987, Copyright © 1995 by American Physiological Society
Pancreatic polypeptide stimulates gastric acid secretion through a vagal mechanism in rats
D. M. McTigue and R. C. Rogers
Department of Physiology, Ohio State University, Columbus 43210, USA.
The present study examined the effect of pancreatic polypeptide (PP) on
gastric acid secretion. A 45-min infusion of PP was delivered into the
jugular vein of urethan-anesthetized rats. Rat PP (100 pmol) significantly
increased acid secretion over baseline; bilateral cervical vagotomy or
peripheral atropine both eliminated this acid response. Neither
intraperitoneal infusion nor close intra-arterial infusion of 100 pmol PP
into the gastric circulation altered acid secretion. These results suggest
that although PP requires intact vagal reflexes to stimulate acid output,
it does not act on afferent or presynaptic efferent terminals of the vagus
or directly within the stomach. Given that vagal reflexes consist of an
afferent limb, an efferent limb, and a central relay, it may be that the
target of circulating PP lies within the central nervous system. Indeed,
previous studies from our laboratory have shown that microinjection of PP
into the dorsal vagal complex results in long-lasting vagal-dependent
elevation of gastric acid secretion.
