Intracerebroventicular injection of prostaglandin E-1 increases gamma-aminobutyric acid level in the posterior hypothalamus

The level of gamma-aminobutyric acid (GABA) in the posterior hypothalamus, the firing rate of the nerves innervating interscapular brown adipose tissu e (IBAT), IBAT and colonic temperatures (T-IBAT and T-c) were monitored in urethane-anesthetized male Sprague-Dawley rats. These variables were measur ed before and after an intracerebroventricular injection of 500 ng prostagl andin E-1 (PGE(1)). The same variables were monitored in other rats with sa line injection. The results showed that PGE1 caused an increase in GABA con centration, firing rate, T-IBAT, T-c These findings suggest that GABA-ergic tone in the posterior hypothalamus is important in the control of the symp athetic and thermogenic changes induced by PGE(1). (C) 2000 Elsevier Scienc e Ltd. All rights reserved.