A subthreshold concentration of baclofen selectively blocks ethanol potentiation of proximal GABA_A IPSCs. A summary of the effect of 500 nm baclofen (BAC) pretreatment on the effect of 80 mm ethanol (EtOH), 1 μm FLU, and 50 μm pentobarbital (PENTO) on the area of proximal GABA_A IPSCs is shown. ^*Significant difference relative to control, paired t tests; ^# significant difference between two conditions, unpaired t tests; NS, no significant difference. Traces are averages of 6-10 GABA_A IPSCs recorded from representative cells under the conditions indicated. Note that 500 nm BAC alone has no effect on proximal GABA_A IPSCs and does not interact with FLU or PENTO potentiation of these responses. In contrast, 500 nm BAC pretreatment reverses the effect of ethanol on proximal IPSCs from potentiation to inhibition.