CALCIUM SPARKS - ELEMENTARY EVENTS UNDERLYING EXCITATION-CONTRACTION COUPLING IN HEART-MUSCLE
CALCIUM SPARKS - ELEMENTARY EVENTS UNDERLYING EXCITATION-CONTRACTION COUPLING IN HEART-MUSCLE
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DOI：
10.1126/science.8235594
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发表时间：
1993-10-29
期刊：
影响因子：
56.9
通讯作者：
CANNELL, MB
中科院分区：
文献类型：
--
作者：
CHENG, H;LEDERER, WJ;CANNELL, MB
在静止的大鼠心脏细胞中，用激光扫描共聚焦显微镜和荧光钙指示剂fluo-3检测到细胞内钙浓度的自发局部增加，称为“钙火花”。与火花相关的钙通量的估计表明，钙火花导致自发开放的单个肌浆网（SR）钙释放通道，这一发现支持的火花动力学的ryanodine依赖性变化。在静息细胞内钙浓度下，这些SR钙释放通道的开放速率较低（约为每秒0.0001次）。然而，SR的钙含量的增加与开放率的四倍增加相关，并导致一些火花触发细胞内钙浓度增加的传播波。钙火花是兴奋-收缩耦合的基础事件的结果，并为哺乳动物心脏细胞内钙浓度的自发和触发变化提供了解释。
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.