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Analysis of origin and spreading of Ca^<2+> transients by digital imaging system in isolated cardiac cells.

通过数字成像系统分析离体心脏细胞中Ca ^ 2 瞬变的起源和传播。

基本信息

批准号：
04660330
负责人：
TEMMA Kyosuke
金额：
$ 1.34万
依托单位：
Kitasato University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04660330/
关键词：
Ca^<2+> transient Single cell Heart Digital image analysis

项目摘要

To examine the origin and spreading of the Ca^<2+> transients following electrical stimulation of isolated myocyte, a system capable of recording intracellular Ca^<2+> distribution with sufficient temporal and spatial resolution was constructed. The system consists of an inverted epifuorescent microscope with a computer-controlled CCD camera and a digital image analyzer. With ths system, it is possible to collect a fluorescent picture every 4 msec. In this study, single myocytes obtained from guinea pig or rat hearts were used. Ca^<2+> transient was monitored using fura-2 as the Ca^<2+> indicator. This was a two year study conducted from 1992 throught 1993. Experimental results are summarized as follows.Ca^<2+> transients triggered by electrical stimulation originated from one or a few sites, or almost entire part of a myocyte. When the Ca^<2+> transient initiated at one site, it took approximately 30 msec to propagate to the other end of the myocyte. A peak of the Ca^<2+> transient was observed about 80 msec after electrical stimulation. The mumber of the initiating sites was increased by isoproterenol which stimulates Ca^<2+> channels, and decreased by verapamil which inhibits Ca^<2+> channels. Ouabain, which increases intracellular Ca^<2+> concentration but has n direct effect on Ca^<2+> channels, failed to alter the number of initiating sites. Doxorubicin, shown to inhibit the Ca^<2+> release mechanism of sarcoplasmic reticulum, did not alter the number of initiating sites athough this agent delayd time to peak Ca^<2+> transients remarkably.These results ndicate that each cell has preferential site(s) at which Ca^<2+> transients originate responding to membrane depolarization. Cz^<2+> transients may be initiated by Ca^<2+> influx via Ca^<2+> channels, and propagate within a cell as the wave of Ca^<2+> induced Ca^<2+> release from sarcoplasmic reticulum.

为了研究电刺激离体心肌细胞后Ca^2+瞬变的起源和传播，我们构建了一个能够以足够的时间和空间分辨率记录细胞内Ca^2+分布的系统。该系统包括一个倒置的落射显微镜与计算机控制的CCD相机和数字图像分析仪。利用该系统，可以每4毫秒收集一次荧光图像。在这项研究中，使用了从豚鼠或大鼠心脏获得的单个心肌细胞。使用fura-2作为Ca^2+指示剂监测Ca^2+瞬变。这是一项从1992年到1993年进行的为期两年的研究。实验结果总结如下：电刺激引起的Ca^2+瞬变起源于一个或几个部位，或几乎整个肌细胞。当Ca^2+瞬变在一个部位开始时，大约需要30毫秒才能传播到肌细胞的另一端。在电刺激后约80毫秒观察到Ca^<2+>瞬变的峰值。异丙肾上腺素刺激Ca^<2+>通道时，起始位点数目增加，维拉帕米抑制Ca^<2+>通道时，起始位点数目减少。哇巴因可增加细胞内Ca^2+浓度，但对Ca^2+通道无直接作用，但不能改变起始位点的数量。多柔比星能抑制肌浆网的Ca^2+释放机制，但并不改变起始位点的数目，尽管它能显著延迟Ca^2+瞬变峰的时间，这些结果表明，每个细胞都有优先的Ca^2+瞬变起始位点，对膜去极化作出反应。Cz^2+瞬变可由Ca ^2+通过Ca^2+通道内流引发，并在细胞内以Ca^2+诱导的肌浆网Ca ^2+释放波的形式传播。