GABA levels and receptor binding after acute and chronic ethanol administration

Abstract

Acute ethanol administration decreased cerebellar GABA levels in rats which were stressed before the sacrifice but not in unstressed controls. After termination of chronic ethanol administration, GABA levels were decreased in the cerebellum and pons medulla oblongata. GABA receptor binding in the synaptosomal preparation of cerebral cortex was similar in controls and rats sacrificed 1 hour after the last ethanol dose but it was decreased in rats sacrificed during withdrawal. In the cerebellum there was no significant difference of GABA receptor binding between control rats and rats sacrificed 1 or 16 hours after the last ethanol dose. However, rats which were minimally affected by ethanol administration had higher binding than control or affected rats. GABA level in the cerebrospinal fluid of heavy drinkers who did not have seizures before the lumbar puncture was higher than in patients who were only occasional drinkers. However, patients who drank heavily and had a seizure before lumbar puncture had GABA levels similar to control levels. These results indicate that ethanol affects GABA-ergic system and that compensatory changes of GABA-ergic activity modify expression of the ethanol withdrawal.