Figure 1.

Ethanol potentiation of IPSCs is stronger in dnActRIB CA1 pyramidal cells than in their wt counterparts. Representative current traces illustrate the differential enhancement by low ethanol (30 mM) of IPSCs in neurons from wt (a) and transgenic mice (b). Evoked IPSCs were sensitive to bicuculline indicating that they were mediated by GABA_ARs (a). Dose–response curves summarize the significantly stronger effects of ethanol on IPSC peak amplitude (c) and area (d) in mutant neurons compared with wt neurons at all concentrations (n=7–14 for each data point). (e) Ro 15-4513 (300 nM) abrogated the pronounced enhancement of IPSCs by low ethanol in mutant neurons (30 mM, n=6–7). (f) Just like IPSCs, current responses to local brief application of the GABA_AR agonist, muscimol (20 μM), were more sensitive to ethanol in dnActRIB neurons than in wt neurons. Inset above histogram depicts current responses evoked by brief muscimol pulses delivered to the dendritic region of the recorded neuron through a second pipette, which was attached to a pressure application system (n=5–7). *P<0.05. dnActRIB, dominant-negative activin receptor IB mutant; IPSC, inhibitory postsynaptic current; wt, wild type.