Pyy in brainstem nuclei induces vagal stimulation of gastric acid
secretion in rats.
Yang, Hong, and Yvette Tach[acute]e.
CURE/Gastroenteric Biology Center, Veterans Wadsworth Medical
Center, Department of Medicine and Brain Research Institute,
University of California, Los Angeles, California, 90073
APStracts 2:0018G, 1995.
The influence of peptide YY (PYY) microinjected into brainstem nuclei
on gastric acid secretion (GAS) was investigated in urethan
-anesthetized rats with gastric cannula. PYY (30-200 ng) microinjected
into the dorsal motor nucleus of the vagus (DMN) induces a dose
-related and vagal dependent stimulation of GAS (net increase: from 13
+/- 4 to 59 +/- 12 [mu]mol/90 min). PYY (200 ng) injected into sites
adjacent to the DMN, intravenously or intracisternally had no effect.
The GAS induced by PYY into the DMN was potentiated by co-injection
of either TRH (30 ng) or the 5-HT2 agonist, DOI (357 ng) and by
microinjection of kainic acid (1 ng) into the raphe pallidus. Prepro
-TRH-(160-169) (200 ng, into the DMN) did not influence the
stimulatory effect of PYY. PYY (200 ng) microinjected into the raphe
pallidus, raphe obscurus and nucleus ambiguus also increased GAS
although the response was of shorter duration than that in the DMN.
These results indicate that PYY acts in brainstem nuclei involved in
the vagal regulation of GAS and that PYY action in the DMN is
potentiated by TRH or 5-HT2 receptor agonist acting at this site.
Received 26 August 1994; accepted in final form 25 April 1995.
APS Manuscript Number G323-4.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 February 1995.