Fig. 7.

Time-dependent block of inactivation-deficient rNav1.4-WCW Na⁺ currents at various ranolazine concentrations. The decaying phase of Na⁺ currents in the presence of ranolazine shown in Fig. 6A were each normalized with respect to the control current trace without drug and fitted by a single exponential function. Normalization was applied to remove the slow-decaying component found in the control. The inverse of the time constant, τ, was plotted against ranolazine concentration (y-intercept: 22.1 ± 2.3, n = 5; slope: 8.2 ± 0.2; linear correlation coefficient r = 0.997).