Excitatory synapse

An excitatory synapse is a synapse in which an action potential in the presynaptic cell increases the probability of an action potential occurring in the postsynaptic cell (see also: EPSP)).

At an excitatory synapse, the neurotransmitter opens sodium (Na+) channels, a slight depolarization of the receiving neuron occurs because of the movement of the positively charged sodium ions into the cell.