Because of the presence of both activation and inactivation gates, voltage-gated Na channels can be all of these.
Sodium voltage-gated channels can be either closed, open, or inactive.
Voltage-gated sodium channels are closed when at rest. Both an activation gate and an inactivation gate are present in voltage-gated sodium channels.
Although the inactivation gate is open, the activation gate is closed. This conformation is closed but capable of opening. Some of the activation gates open as a result of membrane depolarization brought on by a stimulus.
Both the activation and inactivation gates will be opened at this point. As sodium ions enter the cells, nearby activation gates will open.
A greater amount of sodium will enter the cells as a result, initiating an action potential.
Both gates open when certain depolarization thresholds are reached. Action potential increases to its maximum as sodium rushes into the cell.
The inactivation gate will gradually close and the permeability of the membrane to sodium ions will decrease. The channel is now in a state known as "closed but not capable of opening."
Up until the membrane potential reaches its resting state, this occurs. The channels once more assume the "closed but capable of opening" conformation when resting values are attained.
