Reduced ankyrin-G expression does not affect Nav1.5 inactivation in primary cardiomyocytes. Superimposed Nav1.5 inactivation curves obtained from neonatal rat cardiomyocytes treated with control (black squares) and species-specific (human, gray circles; rat, white squares) ankyrin-G shRNA viruses. The normalized INa plotted against preconditioning pulse potential was fitted using a Boltzmann equation. Voltage-dependent steady-state inactivation was determined using a paired two-pulse protocol. Each conditioning voltage is paired with a control after 1.5 s. A 500-ms conditioning pulse from −120 to 20 mV in 10-mV increments was followed by a test pulse to −30 mV. The test pulse in each series is separated from the conditioning pulse by a 2-ms interval to −120 mV. Each point (INa) is normalized against the amplitude of corresponding control pulse (INamax). Each point represents mean ± SEM (error bars; n = 5).
