Production of an action
potential in a neuron needs the presence of voltage-gated channels. At the peak
of the action potential, voltage-gated channels begin to inactivate when enough
sodium has entered the neuron and the membrane's potential has become high. With
its inactivation gate closed, some factor depolarize the membrane
potential sufficiently that leads to the falling phase of the action
potential and voltage-gated
potassium channels begin to open.
