Rapid depolarization (phase 0) of the action potential of ventricular muscle results from opening of:

Ans. B. Voltage-gated Na+ channelsVoltage-gated Na+ channels are responsible for phase 0 in ventricular muscle. Voltage gated Ca2+ channels are responsible for phase 0 in nodal cells. The potassium channels mentioned do not play a role in mediating depolarization.