Effects of chronic exposure to and subsequent withdrawal of ethanol on GABA-induced Cl- currents in cultured hippocampal neurons in the whole-cell patch-clamp configuration. A, Representative tracings recorded from a control cell showing Cl- currents evoked by GABA at concentrations of 0.01-300 μm. The period of GABA application is indicated by the horizontal bar. B, Dose-response curves for GABA-evoked Cl- currents in control cells, cells exposed to 100 mm ethanol for 5 d, and cells subjected to ethanol withdrawal for 6 hr. Data were normalized with respect to the maximal current amplitude apparent at 300 μm GABA and are means ± SE of values from 6-10 neurons. C, Maximal current density for GABAA receptor-mediated currents in neurons of the three experimental groups described in B. Data are means ± SE of values from 18-23 neurons. *p < 0.05 versus control neurons.