Ethanol increases presynaptic GABA_B receptor tone. Traces from representative experiments illustrate that 20 μm SCH 50911 potentiates the area of proximal GABA_A IPSCs in the presence (B) but not the absence (A) of ethanol (EtOH). Note that this concentration of SCH 50911 is sufficient to completely block the inhibitory effect of 5 μm BAC on GABA_A IPSCs. CTL, Control; WASH, washout. C, Summary of the effect of 20 μm SCH 50911 on the area of GABA_A IPSCs recorded in the absence and presence of EtOH. ^*p < 0.05, relative to control. Numbers in parentheses represent the number of cells tested under each experimental condition.