Fourth ventricle injection of corticotropin-releasing factor and
gastric emptying of glucose during gastric fill in the rat..
Smedh, U., K. Uvn[umlaut]as-Moberg, H. J. Grill, and J. M. Kaplan.
Department of Physiology and Pharmacology, Karolinska Institutet,
Stockholm, Sweden, and Department of Psychology, University of
Pennsylvania, Philadelphia, USA
APStracts 2:0191G, 1995.
The effect of corticotropin-releasing factor (CRF) administered into
the fourth ventricle on the gastric emptying of a 12 ml intragastric
infusion of 12.5 % D-glucose, was examined in non-deprived male rats.
All three CRF doses tested (10, 100, and 1000 pmol) significantly
reduced (by 28, 29, 44 %, respectively) the amount of glucose emptied
from the stomach at the end of the 12-min (1.0 ml/min) gastric
infusion interval. The 10 pmol effective dose is the lowest yet
reported to influence gastric emptying. The receptor specificity of
the exogenous CRF (1000 pmol) effect was demonstrated by its complete
blockade by preinjection of [alpha]-helical CRF 9-41 (10 nmol) into
the fourth ventricle. Injection of the antagonist alone, however, did
not affect glucose emptying, indicating little activation of the
targeted receptors under the present non-stressful, baseline
conditions. Our results suggest that of the central CRF receptor
systems that influence gastric emptying, those in the caudal
brainstem, targeted by fourth ventricular injection, may be of
particular importance.
Received 26 June 1995; accepted in final form 4 September 1995
APS Manuscript Number G271-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 31 October 95