The amount of transmitter released from a synapse by each nerve impulse typically varies as a function of previous synaptic activity. These stimulation-induced changes in transmitter release produce changes in postsynaptic potential amplitudes and synaptic efficacy and occur at most central and peripheral chemical synapses. Such changes in synaptic efficacy are also referred to as use-dependent or historical effects, since the previous use (history) of the synapse determines its current efficacy. Depending on the particular synapse, stimulation pattern, and levels of transmitter release, repetitive stimulation can increase or decrease synaptic efficacy, and the time course of these effects can range from milliseconds to days. This article focuses on short-term changes in synaptic efficacy which last from milliseconds to tens of minutes.
ASJC Scopus subject areas