Abstract
Evidence obtained in recent years indicates that, in cardiac myocytes, release of Ca 2+ from the sarcoplasmic reticulum (SR) is regulated by changes in the concentration of Ca 2+ within the SR. In this review, we summarize recent advances in our understanding of this regulatory role, with a particular emphasis on dynamic and local changes in SR [Ca 2+]. We focus on five important questions that are to some extent unresolved and controversial. These questions concern: (1) the importance of SR [Ca 2+] depletion in the termination of Ca 2+ release; (2) the quantitative extent of depletion during local release events such as Ca 2+ sparks; (3) the influence of SR [Ca 2+] refilling on release refractoriness and the propensity for pathological Ca 2+ release; (4) dynamic changes in SR [Ca 2+] during propagating Ca 2+ waves; and (5) the speed of Ca 2+ diffusion within the SR. With each issue, we discuss data supporting alternative viewpoints, and we identify fundamental questions that are being actively investigated. We conclude with a discussion of experimental and computational advances that will help to resolve controversies. This article is part of a special issue entitled "Local Signaling in Myocytes.".
Original language | English |
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Pages (from-to) | 304-311 |
Number of pages | 8 |
Journal | Journal of Molecular and Cellular Cardiology |
Volume | 52 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2012 |
Keywords
- Arrhythmia
- Ca spark
- Ca transient
- Ca wave
- Mathematical modeling
- Triggered activity
- Ventricular myocyte