Presynaptic facilitation of synaptic transmission in the hippocampus.

Biochemical and genetic characterization of proteins in presynaptic axon terminals have led to models of the biochemical pathways underlying synaptic vesicle docking, activation, and fusion. Several studies have attempted recently to assign a precise physiological role to these proteins. This review deals with some of these studies, concentrating on those performed with hippocampal synapses. It is shown that changes in the state of these presynaptic proteins, together with modifications in Ca2+ dynamics in axon terminals, functionally determine the level of basal synaptic transmission, and underlie pharmacologically induced and activity-dependent facilitation of transmitter release in the central nervous system.