LOCAL CALCIUM TRANSIENTS TRIGGERED BY SINGLE L-TYPE CALCIUM-CHANNEL CURRENTS IN CARDIAC-CELLS
LOCAL CALCIUM TRANSIENTS TRIGGERED BY SINGLE L-TYPE CALCIUM-CHANNEL CURRENTS IN CARDIAC-CELLS
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DOI：
10.1126/science.7754383
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发表时间：
1995-05-19
期刊：
影响因子：
56.9
通讯作者：
WIER, WG
中科院分区：
文献类型：
--
作者：
LOPEZLOPEZ, JR;SHACKLOCK, PS;WIER, WG
在哺乳动物心脏细胞中研究了l型钙离子通道打开概率降低的兴奋-收缩耦合。电压钳去极化期间的共聚焦显微镜显示细胞内钙离子浓度的不同局部瞬态（[Ca2+](i)）。当电压变化时，如果肌浆网（SR）的Ca2+释放通过l型Ca2+通道与Ca2+通量紧密相关，而不是通过Na-Ca交换器或平均[Ca2+](i)与Ca2+通量紧密相关，则局部[Ca2+](i)瞬态发生的潜伏期和相对概率会发生变化。电压对局部[Ca2+](i)瞬态振幅没有影响。因此，激活Ca2+从SR释放的最有效的“Ca2+信号”可能是在单个开放的l型Ca2+通道下的高[Ca2+](i)的瞬态微域。
Excitation-contraction coupling was studied in mammalian cardiac cells in which the opening probability of L-type calcium (Ca2+) channels was reduced. Confocal microscopy during voltage-clamp depolarization revealed distinct local transients in the concentration of intracellular calcium ions ([Ca2+](i)). When voltage was varied, the latency to occurrence and the relative probability of occurrence of local [Ca2+](i) transients varied as predicted if Ca2+ release from the sarcoplasmic reticulum (SR) was linked tightly to Ca2+ flux through L-type Ca2+ channels but not to that through the Na-Ca exchanger or to average [Ca2+](i). Voltage had no effect on the amplitude of local [Ca2+](i) transients. Thus, the most efficacious ''Ca2+ signal'' for activating Ca2+ release from the SR may be a transient microdomain of high [Ca2+](i) beneath an individual, open L-type Ca2+ channel.