AJP - Regulatory, Integrative and Comparative Physiology, Vol 259, Issue 3 447-R452, Copyright © 1990 by American Physiological Society
Effects of glucoprivation on gastric motility and pituitary oxytocin secretion in rats
R. K. Cato, L. M. Flanagan, J. G. Verbalis and E. M. Stricker
Department of Behavioral Neuroscience, University of Pittsburgh, Pennsylvania 15260.
Pharmacological doses of insulin (3-25 U/kg sc) elicited feeding and
increased gastric motility in rats. In contrast, the glucose analogue
2-deoxy-D-glucose (2-DG), given ip in doses known to increase food intake,
had dose-dependent effects on gastric motility: 100 and 200 mg/kg 2-DG
increased gastric motility, whereas 500 mg/kg 2-DG virtually eliminated
gastric contractions. This latter result resembled the known effects on
gastric motility of cholecystokinin (CCK) and LiCl. Moreover, like CCK and
LiCl, 500 mg/kg 2-DG stimulated pituitary oxytocin (OT) secretion, and its
effects on gastric motility and OT secretion were potentiated by
pretreatment with the opioid antagonist naloxone. In contrast, OT secretion
was not affected by insulin-induced hypoglycemia with or without naloxone
pretreatment. These results suggest that there are two components to the
effects of 2-DG on gastric motility: an insulin-like excitatory component
and a CCK-LiCl-like inhibitory component. The latter inhibitory component
may be mediated by the paraventricular nucleus of the hypothalamus, which
has already been implicated in the inhibitory control of gastric motility.
