Figure 3. Assessment of subunit-dependent effects of allosteric modulatory effects of meprobamate on GABA_A receptors.

A, Representative traces demonstrating direct allosteric potentiation by meprobamate of GABA-gated (EC₂₀) currents in α1β2γ2, α3β2γ2, α1β1γ2 and α1β2 receptors. B, C and D, summary data of allosteric effects of meprobamate associated with varying α β and γ subunits, respectively. Allosteric potentiation was present in all αβγ receptors, but greatest in those expressing the α5 subunit; absence of the γ subunit also resulted in enhanced potentiation. Note for this and other figures assessing allosteric modulation, underlying direct gating effects were subtracted out for calculation of summary data. Each data point represents the mean ± S.E.M. of a minimum of 4 cells. *, P < 0.05; ***, P < 0.001.