VARIATION OF INTRACELLULAR CA-2+ FOLLOWING CA-2+ CURRENT IN HEART - A THEORETICAL-STUDY OF IONIC-DIFFUSION INSIDE A CYLINDRICAL CELL
VARIATION OF INTRACELLULAR CA-2+ FOLLOWING CA-2+ CURRENT IN HEART - A THEORETICAL-STUDY OF IONIC-DIFFUSION INSIDE A CYLINDRICAL CELL
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DOI：
10.1016/s0006-3495(83)84445-2
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发表时间：
1983-01-01
影响因子：
3.4
通讯作者：
HORACKOVA, M
中科院分区：
文献类型：
--
作者：
FISCHMEISTER, R;HORACKOVA, M
本文研究了一个圆柱形细胞内的扩散物质在肌膜上随时间变化的浓度。应用此方法研究了蛙心慢内向钙电流（伊卡）引起的细胞内游离钙浓度（[Ca ~（2+）]i）的局部变化。在0 mV电压钳去极化过程中，膜内侧的[Ca 2 +]i比细胞中心的[Ca 2 +]i上升得更早和更快。细胞内Ca ~（2+）与特定位点的结合增强了2种浓度之间的偏差，并可能在膜附近产生Ca ~（2+）的积累-耗尽过程。它还降低了整体[Ca 2 +]i。肌浆Ca 2+的相对缓慢的扩散并不显着影响伊卡的动力学通过在跨膜的Ca 2+梯度的修改。
The variation in the concentration of a diffusing substance inside a cylindrical cell submitted to a time-dependent flux at the sarcolemmal membrane was studied. An application was derived to estimate the local modifications of intracellular free Ca2+ concentration ([Ca2+]i) induced by the slow inward Ca2+ current (ICa) in frog heart. During a 0 mV voltage clamp depolarization, [Ca2+]i at the inner side of the membrane rises earlier and faster than [Ca2+]i at the center of the cell. The binding of intracellular Ca2+ to specific sites enhances the deviation between the 2 concentrations and may generate an accumulation-depletion process of Ca2+ near the membrane. It also decreases the overall [Ca2+]i. The relatively slow diffusion of sarcoplasmic Ca2+ does not significantly affect the kinetics of ICa through a modification in the Ca2+ gradient across the membrane.