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. 1998 Aug;75(2):595–600. doi: 10.1016/S0006-3495(98)77550-2

Saltatory propagation of Ca2+ waves by Ca2+ sparks.

J Keizer 1, G D Smith 1, S Ponce-Dawson 1, J E Pearson 1
PMCID: PMC1299735  PMID: 9675162

Abstract

Punctate releases of Ca2+, called Ca2+ sparks, originate at the regular array of t-tubules in cardiac myocytes and skeletal muscle. During Ca2+ overload sparks serve as sites for the initiation and propagation of Ca2+ waves in myocytes. Computer simulations of spark-mediated waves are performed with model release sites that reproduce the adaptive Ca2+ release observed for the ryanodine receptor. The speed of these waves is proportional to the diffusion constant of Ca2+, D, rather than D, as is true for reaction-diffusion equations in a continuous excitable medium. A simplified "fire-diffuse-fire" model that mimics the properties of Ca2+-induced Ca2+ release (CICR) from isolated sites is used to explain this saltatory mode of wave propagation. Saltatory and continuous wave propagation can be differentiated by the temperature and Ca2+ buffer dependence of wave speed.

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Selected References

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