Central somatostatin prevents vagal efferent nerve excitation
produced by trh but not by 2-deoxy-d-glucose.
Masuda, Masao, Setsuko Kanai, and Kyoko Miyasaka.
Department of Clinical Physiology, Tokyo Metropolitan Institute of
Gerontology, Tokyo-173, Japan
APStracts 3:0231G, 1996.
Thyrotropin-releasing hormone (TRH) administered intra
-cerebroventricularly and intravenous injection of 2-deoxy-D-glucose
(2-DG) stimulate pancreatic exocrine secretion via vagal efferent
nerve excitation. We examined whether centrally administered
somatostatin would inhibit pancreatic exocrine secretion that was
stimulated by vagal efferent nerve excitation in conscious rats. The
animals were prepared with cannulae draining bile and pancreatic
juice separately, and with a duodenal cannula, a cerebroventricular
cannula and a right jugular vein cannula. Intracerebroventricular
injection of somatostatin (0.4 or 4 nmol) significantly inhibited
pancreatic secretion induced by TRH (50 or 500 pmol) in a dose
-dependent manner. Intravenous injection of somatostatin had no effect
on pancreatic secretion stimulated by TRH. On the other hand,
somatostatin injected centrally did not affect pancreatic secretion
induced by 2-DG (75 mg/kg) or basal secretion. These results suggest
that TRH and 2-DG stimulate vagal efferent nerves via distinct
mechanisms and that central somatostatin selectively inhibits
excitation of the vagus induced by peptidergic (TRH) stimulation.
Received 16 October 1996; accepted in final form 1 October 1996.
APS Manuscript Number G450-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996