Lateral hypothalamic nmda receptors and glutamate as physiological
mediators of eating and body weight control.
Stanley, B. G., V. L. Willett Iii, H. W. Donias, M. G. Dee Ii, and M.
A. Duva.
Departments of Neuroscience and Psychology, University of
California, Riverside, California, 92521
APStracts 2:0255R, 1995.
Stanley, B.G., V.L. Willett III, H.W. Donias, M.G. Dee II, and M.A.
Duva. Lateral hypothalamic NMDA receptors and glutamate as
physiological mediators of eating and body weight control. Am. J.
Physiology. In order to determine whether endogenous lateral
hypothalamic (LH) glutamate and its NMDA receptors might participate
in the stimulation of natural eating, LH injection of the NMDA
antagonist D-AP5 was tested in adult male rats for suppressive
actions on feeding elicited by: 1) NMDA, kainic acid, or AMPA
injected into the LH; 2) food deprivation; and 3) the onset of the
nocturnal period. D-AP5 (10-100 nmol) reduced by 72% to 90% the
approximately 10 gm eating response elicited by NMDA (10 nmol),
without affecting the quantitatively similar eating responses
elicited by kainic acid (1.0 nmol) or AMPA (1.0 nmol). This treatment
also suppressed deprivation-induced eating by as much as 61% and
nocturnal eating by as much as 40%. To determine its long-term
effects, D-AP5 (50 nmol) was injected bilaterally into the LH twice a
day for 8 consecutive days. This treatment caused up to 65%
reductions in daily food intake and body weight loss of up to 13
gm/day. These findings, showing behaviorally selective suppressions
of eating and body weight by D-AP5, argue that endogenous LH
glutamate acts to regulate natural eating and body weight, and that
NMDA receptors participate in these functions.
Received 11 October 1994; accepted in final form 31 August 1995.
APS Manuscript Number R591-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 September 1995.