Voltage-dependent activation was altered by chloride plus acetate in a pH_i-dependent manner. (A–C) Whole-cell recordings from cells bathed in solution containing [Cl⁻]_e = 140 mM and pH_e 7.3 and dialyzed with 60 mM [Cl⁻]_i plus 80 mM [Ace]_i with pH_i 7.3 (A), 60 mM [Cl⁻]_i with pH_i 4.2 (B), and 60 mM [Cl⁻]_i plus 80 mM [Ace]_i with pH_i 4.2 (C). (D) V_m dependence of activation obtained from cells dialyzed with: bluish green triangles, 60 mM Cl⁻ plus 80 mM acetate, pH_i 7.3; blue circles, 60 mM Cl⁻ plus 80 mM acetate, pH_i 4.2; reddish purple circles, 60 mM Cl⁻, pH_i 4.2. Continuous black line is corresponding voltage activation curve obtained from cells dialyzed with 60 mM Cl⁻, pH_i 7.3, shown in Fig. 3 E. In all cases, [Cl⁻]_e = 140 mM and pH_e 7.3. Continuous lines are Boltzmann fits yielding the following V_0.5 and z values: bluish green triangles, −61.8 ± 1.3 mV and −0.86 ± 0.04 (n = 6); blue circles, −112.4 ± 4.1 mV and −0.83 ± 0.05 (n = 5); reddish purple circles, −121.3 ± 1.6 mV and −0.80 ± 0.04 (n = 8). Error bars represent mean ± SEM.