Fig. 3. Representative examples of the potentiation of EC20γ-aminobutyric acid responses by propofol (2 μm), etomidate (3 μm), and pregnenolone (50 nm). Whole cell current records were obtained from human embryonic kidney 293 cells expressing ( A ) wild-type α1β2γ2sand ( B ) mutant α1β2(Y444W)γ2sreceptors. Bars above the current traces indicate the duration of γ-aminobutyric acid ( filled bars ) and modulator ( open bars ) application. Calibration bars denote 10 s and 100 pA.