Fig. 1. γ-Aminobutyric acid (GABA) concentration-response curves and etomidate left shifts. Each  panel displays mean ± SD data for peak GABA-activated oocyte currents normalized to the maximum response.  Solid symbols represent control data (no etomidate).  Open symbols represent responses measured in the presence of 3.2 μm etomidate.  Lines through data represent nonlinear least squares fits of data to logistic functions. Fitted parameters are reported in  table 1. Lower-right insets in each panel display examples of current sweeps elicited with either 10 or 1,000 μm GABA in a single oocyte (  bars above sweeps indicate application).  Upper left insets in each panel display examples of current sweeps recorded from the same oocyte in the presence of etomidate. (  A ) Wild-type α1β2γ2 l (  squares ). Etomidate strongly potentiates currents at 10 μm GABA and induces a large leftward shift in GABA concentration-responses (14-fold reduction in EC⁵⁰). (  B ) α1β2(N265S)γ2 l (  circles ). Etomidate weakly potentiates currents elicited with 10 μm GABA and induces a small leftward shift in GABA concentration-response (2.3-fold reduction in EC⁵⁰); (  C ) α1β2(N26 5m)γ2 l (  triangles ). Etomidate does not enhance GABA-activated currents and does not significantly shift the GABA concentration-response curve.