A, typical traces obtained from WT (upper) and KO (lower) recordings. Clamp potential was stepped from −80 mV to between +140 and −80 mV. The arrows indicate the zero current level. B, mean I–V curve of total current in WT (▪, n = 15) and KO recordings (•, n = 11). C, mean conductance in WT and KO recordings initially on stepping the potential and at the end of the potential step.