Presynaptic NMDA Receptors

Presynaptic receptors, by virtue of their locations, are ideally suited to influence the efficacy of synaptic transmission by affecting neurotransmitter release.58 In the nervous system, action potential invasion of presynaptic terminals results in a characteristic series of events: initial Ca2+ entry, followed by the activation of presynaptic vesicular release machinery, vesicular fusion, and the release of neurotransmitter into the synaptic cleft.103,105 The efficacy of synaptic transmission is thus governed by the probability of neurotransmitter release, the amount of transmitter released from the presynaptic terminal, the type and number of postsynaptic neurotransmitter receptors, and their response to the released transmitter.