Impaired Inactivation of L-Type Ca2+ Current as a Potential Mechanism for Variable Arrhythmogenic Liability of HERG K+ Channel Blocking Drugs (original) (raw)
Fig 6
Use-dependency of SPX on _I_CaL.
A, Repetitive application of depolarizing pulses (shape is shown in the figure inset) to 0 mV from a holding potential of −50 mV gradually decreased the _I_CaL amplitude. The frequency of depolarizing pulses was 2 Hz. In the presence of SPX, the gradual decrease of _I_CaL was significantly attenuated. B, Summary of the use-dependent effect of SPX. Normalized current levels are plotted against pulse number (A and B, n = 6; black, control; red, SPX). The amplitudes of steady-state currents of both control and SPX group were normalized by the first current of the control. *P < 0.05 **P < 0.01 (n = 6).