This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bennett, M. R. Articles by Gibson, W. G. Search for Related Content PubMed PubMed Citation Articles by Bennett, M. R. Articles by Gibson, W. G.

The Facilitated Probability of Quantal Secretion within an Array of Calcium Channels of an Active Zone at the Amphibian Neuromuscular Junction

M. R. Bennett ^*, L. Farnell  and W. G. Gibson 

^* The Neurobiology Laboratory, Department of Physiology, The Institute for Biomedical Research, and The School of Mathematics and Statistics, University of Sydney, New South Wales, 2006, Australia

Correspondence: Address reprint requests to Prof. Max Bennett, Neurobiology Laboratory, University of Sydney, N.S.W. 2006, Australia. Tel.: 61-2-9351-2034; E-mail: maxb{at}physiol.usyd.edu.au.

A Monte Carlo analysis has been made of the phenomenon of facilitation, whereby a conditioning impulse leaves nerve terminals in a state of heightened release of quanta by a subsequent test impulse, this state persisting for periods of hundreds of milliseconds. It is shown that a quantitative account of facilitation at the amphibian neuromuscular junction can be given if the exocytosis is triggered by the combined action of a low-affinity calcium-binding molecule at the site of exocytosis and a high-affinity calcium-binding molecule some distance away. The kinetic properties and spatial distribution of these molecules at the amphibian neuromuscular junction are arrived at by considering the appropriate values that the relevant parameters must take to successfully account for the experimentally observed amplitude and time course of decline of F1 and F2 facilitation after a conditioning impulse, as well as the growth of facilitation during short trains of impulses. This model of facilitation correctly predicts the effects on facilitation of exogenous buffers such as BAPTA during short trains of impulses. In addition, it accounts for the relative invariance of the kinetics of quantal release due to test-conditioning sequences of impulses as well as due to change in the extent of calcium influx during an impulse.

This article has been cited by other articles:

				V. Matveev, R. Bertram, and A. Sherman Residual Bound Ca2+ Can Account for the Effects of Ca2+ Buffers on Synaptic Facilitation J Neurophysiol, December 1, 2006; 96(6): 3389 - 3397. [Abstract] [Full Text] [PDF]