Effects of acute and chronic ethanol on the γ-aminobutyric acid system in rat brain

Abstract

The effects of acute and chronic ethanol treatment have been investigated on the cerebral concentration of γ-aminobutyric acid (GABA). In addition, the activities of both l-glutamate 1-carboxylyase (GAD) and 4-aminobutyrate: 2-oxoglutarate aminotransferase (GABA-T) have been measured and also the rate of 3H-GABA disappearance following its intracisternal injection into rat brain. Acute ethanol administration caused no significant change in the GABA concentration. There was, however, an increase in GAD activity, but no change in GABA-T activity or the rate of disappearance of 3H-GABA. Chronic ethanol treatment, on the other hand, caused a 48 per cent increase in GABA concentration. There was no simultaneous change in GAD activity but the GABA-T activity was significantly increased. Again there was no change in the rate of disappearance of 3H-GABA. It is suggested that these effects may be due to an action of ethanol on the metabolic pool of GABA as distinct from the transmitter pool.