Persistent Na+ currents in cells transfected with the Q1491H mutant channel
Persistent non-inactivating Na+ currents were recorded using a 400-ms depolarization pulse from –140 mV to –30 mV (see protocol inset) and were normalized to the peak. The current was inhibited using 25 𝛍M tetrodotoxin (TTX). Only the Q1491H mutant channel displayed a significant decrease in current (2.66 ± 0.29 to 1.25 ± 0.22), indicating the presence of a persistent current (Fig. 6) . TTX had no effect on the G1481V mutant and WT currents, which is indicative of a non-specific leak.