Sarcoplasmic reticulum Ca2+ release channel ryanodine receptor (RyR2)plays a crucial role in aconitine-induced arrhythmias
Sarcoplasmic reticulum Ca2+ release channel ryanodine receptor (RyR2)plays a crucial role in aconitine-induced arrhythmias
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DOI：
10.1016/j.bcp.2008.02.027
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发表时间：
2008-06-01
影响因子：
5.8
通讯作者：
Wang, Zhao
中科院分区：
文献类型：
--
作者：
Fu, Min;Li, Ru-Xin;Wang, Zhao
本研究建立了RyR(2)基因敲除心肌细胞的模型，并阐明了RyR(2)在乌头碱诱导的心律失常中的作用。心肌细胞取自新生SD大鼠心脏。用siRNAs下调RyR(2)的表达。RT-PCR、Western印迹和免疫荧光检测显示RyR(2)表达降低。通过测量细胞内相对钙离子浓度、自发性钙振荡、咖啡因诱导的钙释放和L型钙电流来研究钙信号。在正常心肌细胞中，观察到稳定的、周期性的自发性钙振荡，基础[Ca~(2+)](I)维持在低水平。3mU乌头碱可使钙振荡频率增加，幅度降低，3mU乌头碱作用5min后，基础[Ca~(2+)](I)和咖啡因诱导的Ca~(2+)释放水平升高，L型钙电流被抑制。在RyR(2)基因敲除的心肌细胞中，稳定的、周期性的自发性钙振荡几乎消失，但被乌头碱重新诱发，但不影响基础[Ca~(2+)](I)水平；咖啡因诱导的钙释放水平增加，但L型钙电流被抑制。RyR(2)的改变是乌头碱刺激的重要后果，RyR(2)的激活似乎与乌头碱诱发的心律失常有直接关系。本研究展示了一种通过抑制肌浆网RyR(2)通道的钙离子泄漏来预防乌头碱引起的心律失常的潜在方法。(C)2008 Elsevier Inc.保留所有权利。
The present study established a model of RyR(2) knockdown cardiomyocytes and elucidated the role of RyR(2) in aconitine-induced arrhythmia. Cardiomyocytes were obtained from hearts of neonatal Sprague-Dawlay rats. siRNAs were used to down-regulate RyR(2) expression. Reduction of RyR(2) expression was documented by RT-PCR, western blot, and immunofluorescence. Ca2+ signals were investigated by measuring the relative intracellular Ca2+ concentration, spontaneous Ca2+ oscillations, caffeine-induced Ca2+ release, and L-type Ca2+ currents. In normal cardiomyocytes, steady and periodic spontaneous Ca2+ oscillations were observed, and the baseline [Ca2+](i) remained at the low level. Exposure to 3 mu M aconitine increased the frequency and decreased the amplitude of Ca2+ oscillations; the baseline [Ca2+](i) and the level of caffeine-induced Ca2+ release were increased but the L-type Ca2+ currents were inhibited after application of 3 mu M aconitine for 5 min. In RyR(2) knockdown cardiomyocytes, the steady and periodic spontaneous Ca2+ oscillations almost disappeared, but were re-induced by aconitine without affecting the baseline [Ca2+](i) level; the level of caffeine-induced Ca2+ release was increased but L-type Ca2+ currents were inhibited. Alterations of RyR(2) are important consequences of aconitine-stimulation and activation of RyR(2) appear to have a direct relationship with aconitine-induced arrhythmias. The present study demonstrates a potential method for preventing aconitine-induced arrhythmias by inhibiting Ca2+ leakage through the sarcoplasmic reticulum RyR(2) channel. (C) 2008 Elsevier Inc. All rights reserved.