# What channels in the presynaptic neuron open up in response to an action potential?

May 10, 2017

#### Answer:

Sodium and potassium channels

#### Explanation:

A stimulus would first cause the sodium channels allowing $N {a}^{+}$ to rush into the neuron. The neuron becomes depolarized. The peak voltage of the action potential causes the potassium channels to open and ${K}^{+}$ rushes out thus reversing the depolarization.
Around this time, sodium channels begin to close and the action potential will gradually go back to -70 mV (refractory period).