Figure 6. Lack of region-specific differences in the current–voltage relation of the L-type Ca²⁺ current.

I–V plot of peak current density of I_Ca,L in RV and LV endocardial myocytes. A, I_Ca,L recorded during a voltage-clamp protocol using a depolarizing step for 500 ms to 0 mV from an HP of −40 mV. I_Na was inactivated by the HP of −40 mV and K⁺ currents were blocked by isotonic replacement of K⁺ by Cs⁺, and the addition of 10 mm TEA and 2.5 mm 4-AP. The right panel shows a recording from an RV myocyte and the left panel illustrates a recording from an LV endocardial myocyte. B, the I–V relation of peak I_Ca,L was determined by 500-ms depolarizing steps from −50 to +45 mV from an HP of −40 mV. There was no significant difference in the I_Ca,LI–V relation between RV and LV endocardial myocytes.