A Novel and Lethal De Novo LQT-3 Mutation in a Newborn with Distinct Molecular Pharmacology and Therapeutic Response
Figure 5
Relative sensitivity of peak and late F1473C channel current to three different Na+ channel blockers.
A–C. Averaged normalized currents from F1473C channels evoked by 200 ms depolarizing currents to −10 mV at 0.5Hz in the presence and absence of 50 µM mexiletine (A, n = 5), 50 µM ranolazine (B, n = 15), and 10 µM flecainide (C, n = 5). Traces in the presence of each drug are shown in grey and indicated by an arrow in the inset. Drug-free traces are black. Note that the units and presentation reflect normalization to peak current under drug-free conditions. D. Bar graph summarizes fraction of peak (grey bars) and late current (black bars) blocked by each drug. Each drug inhibited late current preferentially over peak current (* p<<0.05). Inhibition of peak and late current was not significantly different among all drugs tested.