Ethanol enhances GABAA receptor-activated chloride currents in chick cerebral cortical neurons

Primary cultures of cerebral cortical neurons were prepared from 7- to 8-day-old chick embryos. The effect of ethanol on GABA-activated membrane current was examined using whole-cell voltage-clamp recording in cells maintained for 3-25 days in vitro. In approximately 60% of neurons examined ethanol caused a potentiation of the membrane current elicited by GABA. The threshold concentration of ethanol was 1 mM, and the potentiating effect of ethanol on GABA-activated currents was maximal at 10 mM. In many cells higher concentration (40-50 mM) of ethanol inhibited GABA-activated currents. These effects of ethanol were all reversible.