Fig. 2. Direct activation of γ-aminobutyric acid receptor type A (GABAA) receptor currents by etomidate (ETO, Etom). ( A–C ) Voltage-clamp currents elicited first with 300 μm etomidate and then with 1,000 μm GABA in oocytes. Small etomidate responses are magnified ten times ( dotted sweeps ). ( A ) Wild-type α1β2γ2L receptors. ( B ) α1β2(N265S)γ2L. ( C ) α1β2(N265M)γ2L. ( D ) Mean (± SD) data from at least 5 oocytes for each type of receptor. Etomidate-activated currents are normalized to maximal GABA (1–3 mm) currents measured in the same oocyte. Wild-type ( solid squares ); α1β2(N265S)γ2L ( solid circles ); α1β2(N265S)γ2L 10 x responses ( open circles ); α1β2(N265M)γ2L (solid triangles ). Lines through wild-type and β2(N265S) data represent nonlinear least squares fits to logistic functions. Fitted parameters are reported in table 1.