Alterations in extracellullar gaba in the ventral hypothalamus of
rats in response to acute glucoprivation.
Beverly, J. Lee, Marcia F. Beverly, and Michael M. Meguid.
Nutrition Department (ENRHM), Texas Tech University, Lubbock, TX
79409 and Department of Surgery, Surgical Metabolism and Nutrition
Laboratory, SUNY-Health Science Center, Syracuse, NY 13210
APStracts 2:0202R, 1995.
GABAergic mechanisms in the ventral hypothalamus may be involved in
counterregulatory responses to glucoprivic episodes. Microdialysis
probes (1 mm) were placed into the ventromedial hypothalamus (VMH) or
lateral hypothalamus (LHA) of male Sprague-Dawley rats 3.5 h before
2-deoxyglucose (2-DG) administration (200 mg/kg, i.v.). Probes were
perfused (2 mL/min) with RingerOs solution and samples collected
every 10 min from 30 min before to 60 min after 2-DG. By 30 min after
2-DG GABA concentration in VMH dialysate increased in a bimodal
fashion to 204 36% (p<0.01) of baseline and GABA concentration
in LHA dialysate decreased to 77 4% (p<0.01) of baseline. The
changes in dialysate GABA concentrations occurred concurrent with the
animals eating and had returned to baseline by 60 min. When animals
were denied access to food after 2-DG the decrease in LHA GABA was
not apparent and VMH GABA remained 15% above baseline at the end of
the sample period. The results of the present study provide evidence
that GABAergic systems in the ventral hypothalamus are responsive to
alterations in glucose status.
Received 12 January 1995; accepted in final form 13 June 1995.
APS Manuscript Number R28-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 July 1995.