IMR Press / FBL / Volume 20 / Issue 7 / DOI: 10.2741/4360

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article
A Monte Carlo simulation dissecting quantal release at the calyx of Held
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1 Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, P.R. China, 200438
Academic Editors:Boxun Lu, Marian Difiglia
Front. Biosci. (Landmark Ed) 2015, 20(7), 1079–1091; https://doi.org/10.2741/4360
Published: 1 June 2015
(This article belongs to the Special Issue Neuronal disease and physiology)
Abstract

Although quantal release provides a basic control of synaptic strength, its underlying mechanisms remain unclear. Here, we report a refined realistic 3D vesicle fusion model at calyx-type synapses. By refining the micro ultrastructure and combining updated parameters, our model is appropriate for simulating quantal release. First, we confirmed the existence of kiss-and-run fusion and gave a justified estimation of its percentage in spontaneous and stimulated release. Second, we found the location of AMPA receptors caused the huge variation in the mEPSC rise time. Third, glutamate spillover only slightly contributed to the mEPSC decay time in small vesicles but caused a dual-peak event in large vesicles. Fourth, mEPSC rise time increased with amplitude, suggesting the contribution of vesicle size, not glutamate concentration. We also applied our model to the analysis of KCl, CaCl2 and synaptotagmin-2 triggered exocytosis. KCl globally accelerated the mEPSCs, whereas mEPSCs were slowed down in high calcium treatments and synaptotagmin-2 knock-out mice, indicating more kiss-and-run release. In summary, our model provides a convenient method for exploring the detailed mechanism of vesicle fusion.

Keywords
Quantal Release
Fusion Pore
Mcell
Synaptotagmin
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