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Short‐term synaptic plasticity, simulation of nerve terminal dynamics, and the effects of protein kinase C activation in rat hippocampus
Author(s) -
Brager Darrin H.,
Capogna Marco,
Thompson Scott M.
Publication year - 2002
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2001.015842
Subject(s) - synaptic plasticity , neuroscience , neural facilitation , synaptic vesicle , protein kinase c , electrophysiology , neurotransmitter , hippocampal formation , long term potentiation , neurotransmission , hippocampus , microbiology and biotechnology , biology , chemistry , vesicle , biophysics , excitatory postsynaptic potential , kinase , biochemistry , inhibitory postsynaptic potential , central nervous system , receptor , membrane
Phorbol esters are hypothesised to produce a protein kinase C (PKC)‐dependent increase in the probability of transmitter release via two mechanisms: facilitation of vesicle fusion or increases in synaptic vesicle number and replenishment. We used a combination of electrophysiology and computer simulation to distinguish these possibilities. We constructed a stochastic model of the presynaptic contacts between a pair of hippocampal pyramidal cells that used biologically realistic processes and was constrained by electrophysiological data. The model reproduced faithfully several forms of short‐term synaptic plasticity, including short‐term synaptic depression (STD), and allowed us to manipulate several experimentally inaccessible processes. Simulation of an increase in the size of the readily releasable vesicle pool and the time of vesicle replenishment decreased STD, whereas simulation of a facilitation of vesicle fusion downstream of Ca 2+ influx enhanced STD. Because activation of protein kinase C with phorbol ester enhanced STD of EPSCs in rat hippocampal slice cultures, we conclude that an increase in the sensitivity of the release process for Ca 2+ underlies the potentiation of neurotransmitter release by PKC.