How does the ryanodine receptor in the ventricular myocyte wake up: by a single or by multiple open L-type Ca(2+) channels?

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Item Type:	Article
Title:	How does the ryanodine receptor in the ventricular myocyte wake up: by a single or by multiple open L-type Ca(2+) channels?
Creators Name:	Schendel, T., Thul, R., Sneyd, J. and Falcke, M.
Abstract:	We study here the early stage of Ca(2+)-induced Ca(2+) release (CICR) in the diadic cleft of cardiac ventricular myocytes. A crucial question for this mechanism is whether the activation of the ryanodine receptors (RyRs) is triggered by one or by multiple open L-type Ca(2+) channels (LCCs). We address the problem through a modelling approach that allows us to investigate both possibilities. The model is based on a spatially resolved description of a Ca(2+) release unit (CaRU), consisting of the junctional sarcoplasmic reticulum and the diadic cleft, with well-defined channel placement. By taking advantage of largely varying time scales of the Ca(2+) dynamics in the diadic cleft, the governing equations can be reduced to one ordinary differential equation that describes the Ca(2+) fluxes, the electric field due to surface charges and diffusion. Our study shows that the mechanisms of the early stage of CICR shape measurable properties of CICR in a characteristic way. From here we conclude that the activation of RyRs requires multiple open LCCs.
Keywords:	Calcium-Induced Calcium Release, Signalling Micro-Domain, Calcium Dynamics, Mathematical Modelling
Source:	European Biophysics Journal
ISSN:	0175-7571
Publisher:	Springer
Volume:	41
Number:	1
Page Range:	27-39
Date:	January 2012
Official Publication:	https://doi.org/10.1007/s00249-011-0755-7
PubMed:	View item in PubMed

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