Values shown are mean ± SEM. Tagged values are significantly less (*) or greater (^) than wild type (P < 0.05, t test). n indicates the number of whole-cell recordings. Currents were recorded in the whole-cell mode at a holding potential of −70 mV, as in Table 1, but with our standard extracellular solution (pH 7.2) also containing 0.01 mM EDTA. These conditions were aligned to those for on-cell single-channel recording except for the pH. The estimated channel number mediating the observed steady-state whole-cell current amplitudes (I_steady-state) was derived from: I_steady-state = N * P_o * i, where N is the approximate number of channels on the membrane, P_o is the equilibrium P_open, and i is single-channel current amplitude corrected for difference in membrane potential assuming Ohmic behavior (Table 3).