Fig. 3. Isoflurane shifts the dose response curve for the α1(L277A)β2γ2Smutant to the left. γ-Aminobutyric acid (GABA)-induced responses from individual HEK 293 cells expressing wild-type or mutant α subunits in the absence or presence of isoflurane are shown (A and C ). Bars over individual current traces indicate the duration of GABA–isoflurane application. Pooled data are plotted in concentration–effect curves for mutant α1(L277A)β2γ2SGABAAreceptors (D ) in the absence (L277A) and presence (L277A+ISO) of 0.5 mm isoflurane. The data were normalized to the maximal GABA or GABA+ISO response. The concentration–response curve for wild-type GABA receptor in the presence and absence of isoflurane is shown as a reference (B ). Data points shown are the means of multiple normalized experiments (table 3). Bars indicate SEM.