| | |
Summary: Insight into the mechanisms of synaptic modulation is
important for understanding information processing in the
central nervous system (CNS). Modulation of synaptic
transmission occurs at several sites: at presynaptic
terminals, by the activation of presynaptic receptors; at
postsynaptic cells, by change in the postsynaptic receptor
properties; and at the synaptic cleft, by change in the
clearance rate of released transmitter. At the presynaptic
terminal there exist at least four identifiable targets for
modulation of release by receptors. (1) Changes in pre-
synaptic resting Ca2+
concentrations, either by the opening
or closing of presynaptic ligand-gated Ca2+
channels
(Berretta & Jones, 1996; Schwartz & Alford, 1998; Cochilla
& Alford, 1999; Glitsch & Marty, 1999) or by the regulation
of Ca2+
release from internal stores (Cochilla & Alford,
1999). (2) Mechanisms that alter Ca2+
channel gating may
|
