Figure 6.

Mexiletine (MEX) inhibited late I _Na of N1325S and R1623Q mutant channels in a time-dependent manner. Late I _Na was measured from the cells with three individual mutations either without MEX treatment (control) or after incubation with 10 µM MEX for 10 min, and 3, 12, 24, and 48 h, respectively. MEX (10 μM) suppressed late I _Na of all three mutant channels after incubated with MEX for 10 min. The inhibition effects were more pronounced in N1325S and R1623Q mutant channels than that in M1652R mutation with the increases in incubation time. N = 5–9. ^* P < 0.05 compared with control; ^† P < 0.05 compared with 10 min’ exposure of MEX.