Figure 1.

Mutants at residue 1784 in Nav1.5 alter the voltage dependence of conductance and proton block of maximal conductance. (A) Sample macroscopic sodium currents recorded in residue 1784 mutants at extracellular pH 7.4. (B) Normalized GV relationships of residue 1784 mutants at extracellular pH 7.4. Conductance was determined from peak currents measured during depolarizations between −100 and 40 mV (a) from a prepulse potential of −150 mV. (C) Average midpoints of the GV relationships for residue 1784 mutants at extracellular pH 7.4 and pH 6.0 (n = 5–10; Table S1). (D) Fraction of conductance remaining at extracellular pH 6.0 in residue 1784 mutants (n = 5–10). Error bars are SEM.