Regional changes in calcium underlying contraction of single smooth muscle cells.
Regional changes in calcium underlying contraction of single smooth muscle cells.
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单个平滑肌细胞收缩背后钙的区域变化。
DOI：
10.1126/science.3103219
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Fay,FS
中科院分区：
文献类型：
--
作者：
Williams,DA;Becker,PL;Fay,FS
本文利用钙敏感染料fura-2和数字成像显微镜测量平滑肌单个细胞的钙和收缩，探讨了钙在平滑肌收缩状态中的调节作用。用高钾去极化或用苯酚刺激细胞后，细胞质中游离钙的浓度增加。钙的变化总是先于收缩。这些刺激引起的钙的增加被限制在1 μM以内。在收缩期间，细胞核内的钙也受到其上升的限制。核内钙从200 nM上升到不超过300 nM，而细胞质钙则上升到700 nM以上。这些细胞质和核内钙的明显上限可能是由于钙分别在细胞质和核钙通道门控机制上的负反馈，或者是由于钙泵在钙上限处被强烈激活。
The role of calcium in regulating the contractile state of smooth muscle has been investigated by measuring calcium and contraction in single smooth muscle cells with the calcium-sensitive dye fura-2 and the digital imaging microscope. The concentration of free calcium in the cytoplasm increased after stimulation of the cells by depolarization with high potassium or by application of carbachol. Changes in calcium always preceded contraction. The increase in calcium induced by these stimuli was limited to less than 1 μM. Calcium within the nucleus was also subject to a limitation of its rise during contraction. Intranuclear calcium rose from 200 nMat rest to no more than 300 nMwhile cytoplasmic calcium rose to over 700 nM. These apparent ceilings for both cytoplasmic and intranuclear calcium may result either from negative feedback of calcium on cytoplasmic and nuclear calcium channel gating mechanisms, respectively, or from the presence of calcium pumps that are strongly activated at the calcium ceilings.