%0 Journal Article
%T Contribution of spontaneous L-type Ca2+ channel activation to the genesis of Ca2+ sparks in resting cardiac myocytes<br>Contribution of spontaneous L-type Ca~(2+) channel activation to the genesis of Ca~(2+) sparks in resting cardiac myocytes
%A ZHANG Guangqin FU Yu YANG Dongmei HAO Xuemei BAI Shuhua TANG Yiqun Edward G LAKATTA WU Caihong CHENG Heping
%A <br>Edward
%A G
%A LAKATTA
%J 中国科学C辑(英文版)
%D 2004
%I Springer
%X Ca2+ sparks are the elementary events of intracellular Ca2+ release from the sarcoplasmic reticulum in cardiac myocytes. In order to investigate whether spontaneous L-type Ca2+ channel activation contributes to the genesis of spontaneous Ca2+ sparks, we used confocal laser scanning microscopy and fluo-4 to visualize local Ca2+ sparks in intact rat ventricular myocytes. In the presence of 0.2 mmol/L CdCl2 which inhibits spontaneous L-type Ca2+ channel activation, the rate of occurrence of spontaneous Ca2+ sparks was halved from 4.20 to 2.04 events/(100 microm x s), with temporal and spatial properties of individual Ca2+ sparks unchanged. Analysis of the Cd2+-sensitive spark production revealed an open probability of approximately 10(-5) for L-type channels at the rest membrane potentials (-80 mV). Thus, infrequent and stochastic openings of sarcolemmal L-type Ca2+ channels in resting heart cells contribute significantly to the production of spontaneous Ca2+ sparks.
%K Ca2+ sparks
%K L-type Ca2+ channels
%K cardiac myocytes
%K confocal microscopy<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=90BA3D13E7F3BC869AC96FB3DA594E3FE34FBF7B8BC0E591&jid=180CF3A72E750F3261A8A60EDC957784&aid=F0752F6C10CB2BC30672D4A32FAD4259&yid=D0E58B75BFD8E51C&vid=F4B561950EE1D31A&iid=CA4FD0336C81A37A&sid=4AD960B5AD2D111A&eid=42425781F0B1C26E&journal_id=1674-7305&journal_name=ScienceChina.Lifesciences&referenced_num=0&reference_num=12