Heterozygous and homozygous α1β2γ2S(R43Q) receptors had unaltered diazepam sensitivity. A, Whole-cell recordings were made from lifted HEK293-T cells expressing wild-type (wt) hα1β2γ2S or heterozygous (het) or homozygous (hom) hα1β2γ2S(R43Q) receptors. An approximate EC₂₀ value of GABA concentration (2 μm) was applied for 6 sec to cells voltage clamped at -50 mV, and 1 μm diazepam was coapplied with GABA. B, Diazepam enhancement is shown as a percentage of control current (average peak current before and after diazepam coapplication). The γ2S(R43Q) mutation did not alter the magnitude of diazepam enhancement for either heterozygous or homozygous expression with both free hα1β2γ2S assembly and forced rβ2-α1/γ2L assembly (n = 6 for each group).