The Journal of Neuroscience, June 1, 2002, 22(11):4381-4387
Release Dependence to a Paired Stimulus at a Synaptic Release
Site with a Small Variable Pool of Immediately Releasable Vesicles
Eric
Hanse and
Bengt
Gustafsson
Institute of Physiology and Pharmacology, Göteborg
University, SE-405 30 Göteborg, Sweden
Monte Carlo simulations were performed on a release model based on
experimental data from single glutamatergic synapses containing a
single release site in the hippocampal CA1 region of the neonatal rat.
These simulations explored what can be learned about the release
process by examining how the release probability in response to the
second stimulus (P2) of a paired
stimulus to a synapse depends on the release in response to the first
stimulus. Comparisons between experimental data from a number of
individual synapses and the simulated data support the notion that the
immediately releasable vesicle pool is small (approximately one) and
shows substantial intertrial variation. The simulations also show that the release dependence of P2 is not
necessarily an indicator of either intertrial variation in
Ca2+ influx, feedback effects of released
transmitter, or activation failure of the axon.
Key words:
paired-pulse; release probability; hippocampus; CA1; synaptic plasticity; development
Copyright © 2002 Society for Neuroscience 0270-6474/02/22114381-07$05.00/0