Fig. 2.

Diagram illustrating the various states of the sodium channel. The sodium channel is in the closed state at resting potential (orange line in the current trace) and it switches to the open state after a depolarizing stimulus (activation, blue line in the current trace). The opposite mechanism (deactivation) occurs when the potential is repolarized. If the stimulus persists, the channel goes into the inactivated state through the mechanisms of fast and slow inactivation (pink line in the current trace). Repolarization of the membrane potential is also required to allow recovery from inactivation.