Excitation-contraction coupling in heart: new insights from Ca2+ sparks.

@article{Cheng1996ExcitationcontractionCI,
  title={Excitation-contraction coupling in heart: new insights from Ca2+ sparks.},
  author={H. Cheng and M R Lederer and Rui-ping Xiao and Ana Maria Gomez and Y Y Zhou and Bruce D. Ziman and Harold A. Spurgeon and Edward G. Lakatta and W. Jonathan Lederer},
  journal={Cell calcium},
  year={1996},
  volume={20 2},
  pages={
          129-40
        }
}
Ca2+ sparks, the elementary units of sarcoplasmic reticulum (SR) Ca2+ release in cardiac, smooth and skeletal muscle are localized (2-4 microns ) increases in intracellular Ca2+ concentration, [Ca2+]i, that last briefly (30-100 ms). These Ca2+ sparks arise from the openings of a single SR Ca2+ release channel (ryanodine receptor, RyR) or a few RyRs acting in concert. In heart muscle, Ca2+ sparks can occur spontaneously in quiescent cells at a low rate (100 s-1 per cell). Identical Ca2+ sparks… Expand
Ca2+ spark as a regulator of ion channel activity.
TLDR
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TLDR
The local stability of CICR is insured because of strong, use-dependent inactivation of RyRs, that terminates Ca2+ sparks and confers persistent local SR refractoriness, and the global stability is safeguarded by many factors acting in synergy, including physical separation of RyR clusters, sheer Ca2- gradients around the channel pores, and high cooperativity for the Ca2+. Expand
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A comparative analysis of ‘elementary’ Ca2+ release units in mouse, rat and human arterial smooth muscle cells, using measurements of Ca2- sparks and plasmalemmal KCa currents activated by Ca2+. Expand
Termination of cardiac Ca(2+) sparks: an investigative mathematical model of calcium-induced calcium release.
TLDR
A new model of Ca(2+) spark behavior is presented that provides a "proof of principle" test of a new hypothesis for Ca( 2+) spark termination and reproduces critical features of Ca (2+) sparks observed experimentally. Expand
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TLDR
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Calcium sparks in smooth muscle.
TLDR
It is proposed that frequency and amplitude modulation of Ca(2+) sparks by contractile and relaxant agents is an important mechanism to regulate smooth muscle function. Expand
Ca2+ sparks triggered by patch depolarization in rat heart cells.
TLDR
The results suggest that voltage-activated Ca2+ entry through one or a small number of L type Ca 2+ channels triggers the release of Ca2+. Expand
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Cardiomyocytes are electrically excitable cells built to contract. The cellular processes linking electrical excitation, i.e. the sarcolemmal action potential, with contraction are referred to asExpand
Calcium sparks in skeletal muscle fibers.
TLDR
It is suggested that 1-5 active RYRs participate in the generation of a typical voltage-activated spark under physiological conditions, and a major goal of future experiments is to estimate this number more precisely and, if it is two or more, to investigate the communication mechanism that allows multiple RYR to be co-activated in a rapid but self-limited fashion. Expand
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Ca2+ sparks are elementary events that can explain both the initiation and propagation of Ca2+ waves and electrically evoked Ca2+, and interact with each other in a manner that is consistent with both phenomena having the same underlying mechanism(s). Expand
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By comparing the voltage dependence of Ca2+ sparks in rat ventricular myocytes with theCa2+ current, it is shown that the opening of a single SL Ca 2+ channel can trigger a Ca2- spark and it is deduced that the probability of SR Ca2+. Expand
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KCa channels activated by Ca2+ sparks appeared to hyperpolarize and dilate pressurized myogenic arteries because ryanodine and thapsigargin depolarized and constricted these arteries to an extent similar to that produced by blockers of KCa channels. Expand
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