Figure 6: Kinetic change of I_to in normal epicardial cardiomyocytes treated with UNx rat LDL.

(a) Schematic diagram of the voltage clamp protocol of steady-state voltage-dependence inactivation. (b) The original superimposed recordings of steady-state inactivation trace in epicardial cardiomyocytes treated with 100 μg/mL sham and UNx rat LDL. The arrow in each panel indicates zero current level. (c) The voltage-dependent steady-state inactivation curves for I_to were obtained by normalizing the current amplitudes to the maximal value and plotted as a function of the prepulse (conditioning) potentials. The lines drawn through the data points are the best fit to the Boltzmann equation. (d) Histogram comparing slope and midpoint voltage (V_0.5) of each line between epicardial cardiomyocytes from sham and UNx rats. (e) Schematic of the typical 2-pulse protocol of kinetics of I_to recovery from inactivation. (f) The original superimposed recordings of recovery from inactivation in epicardial cardiomyocytes from sham and UNx rats. The arrow in each panel indicates the zero current level. (g) The recovery from inactivation curves for I_to were obtained and fitted to a single exponential function. (h) Histogram comparing the average time constant for recovery from inactivation between epicardial cardiomyocytes from sham and UNx rats. n = 7 from 5 animals per group. *P < 0.05, **P < 0.01 compared to sham LDL group.