Fig. 2. (A ) Superimposed traces of human voltage-dependent Kv1.1 currents evoked by depolarizing steps from a holding potential of −80 mV to test potentials ranging from −70 mV to +50 mV. The interpulse duration was 1 s. Shown are the current traces during control conditions, during the influence of enflurane (3,124 μm) and isoflurane (4,037 μm), and after the drug was washed out. (B ) Concentration response curves for inhibition of maximal Kv1.1 whole cell conductance (Gmax) by enflurane and isoflurane. The concentration of each volatile anesthetic agent was determined by gas chromatography and plotted against the inhibitory effect. IC50values and Hill coefficients are given in the Results.