Eur. Phys. J. Appl. Phys.
Volume 75, Number 1, July 2016
|Number of page(s)||9|
|Section||Biophysics and Biosensors|
|Published online||26 July 2016|
Monte Carlo simulation of the effects of vesicle geometry on calcium microdomains and neurotransmitter release
Biophysics Group, Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
2 Department of Bioengineering, University of California, San Diego, CA 92093, USA
a e-mail: email@example.com
Revised: 10 January 2016
Accepted: 1 June 2016
Published online: 26 July 2016
We investigate the effects of synaptic vesicle geometry on Ca2+ diffusion dynamics in presynaptic terminals using MCell, a realistic Monte Carlo algorithm that tracks individual molecules. By modeling the vesicle as a sphere and an oblate or a prolate spheroid with a reflective boundary, we measure the Ca2+ concentration at various positions relative to the vesicle. We find that the presence of a vesicle as a diffusion barrier modifies the shape of the [Ca2+] microdomain in the vicinity of the vesicle. Ca2+ diffusion dynamics also depend on the distance between the vesicle and the voltage-gated calcium channels (VGCCs) and on the shape of the vesicle. The oblate spheroidal vesicle increases the [Ca2+] up to six times higher than that in the absence of a vesicle, while the prolate spheroidal vesicle can increase the [Ca2+] only 1.4 times. Our results also show that the presence of vesicles that have different geometries can maximally influence the [Ca2+] microdomain when the vesicle is located less than 50 nm from VGCCs.
© EDP Sciences, 2016
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