Motilin is a biosignal controlling the cyclic release of pancreatic
polypeptide via the vagus in fasted dogs.
Mochiki, Erito, Akio Inui, Minoru Satoh, Akiyoshi Mizumoto, and Zen
Itoh.
Gastrointestinal Research Laboratories, Institute for Molecular and
Cellular Regulation, Gunma University, Maebashi; and 2nd Department
of Medicine, Kobe University School of Medicine, Kobe, Japan,
Doctoral Fellow from the First Department of Surgery, Gunma
University School of Medicine, Maebashi, Japan
APStracts 3:0144G, 1996.
The mechanism of associated fluctuations in plasma motilin and
pancreatic polypeptide (PP) concentrations was studied in fasted
conscious dogs while monitoring gastric motility. Plasma motilin and
PP concentrations were measured by radioimmunoassay. In intact normal
dogs, exogenous motilin (0.03-0.3 g/kg) stimulated dose-related
release of PP, but PP did not stimulate motilin release. Motilin
-induced PP release was completely inhibited by pre-treatment with
cholinergic blockers and a 5-hydroxytryptamine (5-HT3) receptor
antagonist, and by vagotomy. The cyclic release of PP was abolished
after vagotomy and duodenectomy, however, PP release stimulated by
exogenous motilin was apparent after duodenectomy, but not after
vagotomy. In conclusion, motilin appears to stimulate PP release via
vagal, cholinergic muscarinic pathways involving 5-HT3 receptors, and
to act as a biosignal controlling PP release by mediating the
interdigestive periodic changes in the duodenum to the center of the
autonomic nervous system. This represents a new role for motilin.
Received 12 December 1995; accepted in final form 19 July 1996.
APS Manuscript Number G519-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 4 August 1996