up: [[Neuron signaling]] Depolarization is the change in charge in a neuronal cell to be closer to zero. Importantly it is the main process through which neuron cells signal to each other through causing [[Action potentials]]. ### How depolarization happens One of the most common causes of depolarization is the action of excitatory neurotransmitters on postsynaptic receptors of neurons. These excitatory stimuluses are called Excitatory Postsynaptic Potentials (EPSP). Calcium's depolarizing tendencies have less to do with it changing the charge of the cell on it's own but more from it activating kinases that activate additional receptors in the ending and send messages to the nucleus.