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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
5134
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pubmed:dateCreated |
1993-11-29
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pubmed:abstractText |
Spontaneous local increases in the concentration of intracellular calcium, called "calcium sparks," were detected in quiescent rat heart cells with a laser scanning confocal microscope and the fluorescent calcium indicator fluo-3. Estimates of calcium flux associated with the sparks suggest that calcium sparks result from spontaneous openings of single sarcoplasmic reticulum (SR) calcium-release channels, a finding supported by ryanodine-dependent changes of spark kinetics. At resting intracellular calcium concentrations, these SR calcium-release channels had a low rate of opening (approximately 0.0001 per second). An increase in the calcium content of the SR, however, was associated with a fourfold increase in opening rate and resulted in some sparks triggering propagating waves of increased intracellular calcium concentration. The calcium spark is the consequence of elementary events underlying excitation-contraction coupling and provides an explanation for both spontaneous and triggered changes in the intracellular calcium concentration in the mammalian heart.
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
0036-8075
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
29
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pubmed:volume |
262
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
740-4
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pubmed:dateRevised |
2007-3-19
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pubmed:meshHeading |
pubmed-meshheading:8235594-Aniline Compounds,
pubmed-meshheading:8235594-Animals,
pubmed-meshheading:8235594-Calcium,
pubmed-meshheading:8235594-Calcium Channels,
pubmed-meshheading:8235594-Fluorescent Dyes,
pubmed-meshheading:8235594-Ion Channel Gating,
pubmed-meshheading:8235594-Microscopy, Fluorescence,
pubmed-meshheading:8235594-Models, Biological,
pubmed-meshheading:8235594-Muscle Proteins,
pubmed-meshheading:8235594-Myocardial Contraction,
pubmed-meshheading:8235594-Myocardium,
pubmed-meshheading:8235594-Rats,
pubmed-meshheading:8235594-Ryanodine,
pubmed-meshheading:8235594-Ryanodine Receptor Calcium Release Channel,
pubmed-meshheading:8235594-Sarcoplasmic Reticulum,
pubmed-meshheading:8235594-Xanthenes
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pubmed:year |
1993
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pubmed:articleTitle |
Calcium sparks: elementary events underlying excitation-contraction coupling in heart muscle.
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pubmed:affiliation |
Department of Physiology, University of Maryland School of Medicine, Baltimore 21201.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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