A PhD student can measure ionic conductance in isolated card…
A PhD student can measure ionic conductance in isolated cardiomyocytes in the electrophysiology laboratory. A goal of the lab is to measure specific effects of cardiac drugs on the initiation and completion of the action potential. The student evaluated several drugs acting on Na+ current (INa), IK, and ICa, and eventually determined the concentrations of drugs necessary to block individual channels contributing to the cardiomyocyte action potential. Currents caused by opening of which of the following channels contribute to the rapid depolarization phase of the action potential of ventricular muscle cells?