THE GAMMA-AMINOBUTYRIC ACID (GABA) SYSTEM IN BRAIN DURING ACUTE AND CHRONIC ETHANOL INTOXICATION

Abstract— The effects of acute and chronic ethanol intoxication on the GAGA system of rats have been investigated. Under the terminal conditions provoked. by ethanol (6–8 g/kg, i.p.) the brain GABA content sharply increased. There was a simultaneous decrease of 35–40% in the glutamate decarboxylase (GAD) activity of the cerebellum and cerebral hemispheres. In contrast, the transaminase, GABA-T was either unchanged, or it increased: by 28% only in cerebellum and by 1.5–2.0–fold in liver and kidney. It is suggested that effects of acute ethanol intoxication at different doses (2–8 g/kg) on the brain GABA system is connected with the phases of the functional condition of the CNS and a disturbance of homeostatic function. Chronic ethanol consumption caused a decrease in brain GABA. an increase of GAD activity in cerebellum and cerebral hemispheres, and no change in GABA-T activity. The activity of this last enzyme was increased 1.5–2.0-fold in liver and kidneys of rats consuming a diet containing 10% ethanol daily. A 50-fold purified preparation of GABA-T obtained from pig brain was inhibited by butanol-l and propanol-1 (0.03–0.6m) with no effect of ethanol. It is suggested that the mechanisms involved in the ethanol effect on nervous cells are linked with the GABA system and the phases of the functional condition of the CNS.