AREA-DEPENDENT CHANGES IN GABAERGIC FUNCTION AFTER ACUTE AND CHRONIC COLD STRESS

(1) The function of the gamma-aminobutyric acid (GABA)ergic system in certain areas of the rat brain was investigated after acute and chroni c cold stress. (2) GABA concentration, [H-3]GABA uptake and the activi ty of the synthesis enzyme glutamate decarboxylase (GAD) were measured . (3) Acute stress: (a) reduced GABA concentration in the corpus stria tum (29%); (b) decreased GAD activity (under non-saturating substrate concentration) in the olfactory bulbs (24%); (c) diminished neuronal u ptake of [H-3]GABA in the frontal cerebral cortex (65%), hypothalamus (86%) and olfactory bulbs (82%). (4) Chronic stress: (a) reduced the e ndogenous levels of GABA in the frontal cerebral cortex (51%), hypotha lamus (26%) and olfactory bulbs (15%); (b) decreased GAD activity in t he corpus striatum (32%) and olfactory bulbs (34%); (c) decreased neur onal uptake of [H-3]GABA in the hypothalamus (83%). (5) These findings suggest that compensatory changes may develop in the GABAergic system after chronic stress.