Suppose that after an action potential we clam p the membrane potential at -50 mV and don’t let it completely repolarize. We find that we cannot elicit an action potential. This is called a depolarization block. What causes it?
A) Persistently elevated gK B) The inactivation gates do not re-open C) The activation gates of the Na channel are closed D) Persistently elevated gNa E) The inactivation gates are stuck open