Article,

A mathematical analysis of the generation and termination of calcium sparks.

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Biophys. J., 86 (3): 1293--1307 (March 2004)

Abstract

Calcium sparks are local regenerative releases of Ca$^2+$ from a cluster of ryanodine receptors on the sarcoplasmic reticulum. During excitation-contraction coupling in cardiac cells, Ca$^2+$ sparks are triggered by Ca$^2+$ entering the cell via the T-tubules (Ca$^2+$-induced Ca$^2+$ release). However under conditions of calcium overload, Ca$^2+$ sparks can be triggered spontaneously. The exact process by which Ca$^2+$ sparks terminate is still an open question, although both deterministic and stochastic processes are likely to be important. In this article, asymptotic methods are used to analyze a single Ca$^2+$ spark model, which includes both deterministic and stochastic biophysical mechanisms. The analysis calculates both spark frequencies and spark duration distributions, and shows under what circumstances stochastic transitions are important. Additionally, a model of the coupling of the release channels via the FK-binding protein is analyzed.

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