Application of blebbistatin as an excitation-contraction uncoupler for electrophysiologic study of rat and rabbit hearts
Application of blebbistatin as an excitation-contraction uncoupler for electrophysiologic study of rat and rabbit hearts
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DOI：
10.1016/j.hrthm.2006.12.047
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发表时间：
2007-05-01
期刊：
影响因子：
5.5
通讯作者：
Efimov, Igor R.
中科院分区：
文献类型：
--
作者：
Fedorov, Vadim V.;Lozinsky, Ilya T.;Efimov, Igor R.
心脏电活动的荧光成像的背景应用受到运动伪影的限制和/或当前可用的药理学激发 - 收缩解偶联剂的副作用。本研究的目的是测试Blebbistatin，最近发现的肌球蛋白II II同工型，最近发现的抑制剂，是否是blebbistatin可以用作激发反偶联器。通过分析泡泡蛋白对Langendorff吞噬兔心的收缩和基本心脏地生理参数的影响来检查。电压敏感和Ca2+敏感染料。在用0.1-10 mu m blebbistatin灌注后确定动作电位形态，心电图参数，心脏传导和耐火性。抗溶液Blebbistatin 5-10 mu M blebbistin在所有心脏准备中完全消除了收缩，但对包括ECG（ECG）没有任何影响，包括ECG参数，心房和心室有效难治期以及心房和心室激活模式。 Blebbistatin 10 AM对兔心脏组织的作用潜在形态没有影响。 BLEBBISTATIN以剂量依赖性的方式抑制单细胞收缩，并以半末端抑制浓度（IC50）= 0.43 MU M，而不会改变细胞内钙瞬变的形态。通过同时冲洗和通过紫外线灌注布孔蛋白的光漂白是一种有希望的新型选择性的选择性激发诱导解偶联剂，可用于心脏组织的光学成像。
BACKGROUND Application of fluorescence imaging of cardiac electrical activity is limited by motion artifacts and/or side effects of currently available pharmacologic excitation-contraction uncoupling agents.OBJECTIVES The purpose of this study was to test whether blebbistatin, a recently discovered inhibitor of myosin II isoforms, can be used as an excitation-contraction uncoupler.METHODS The specificity and potency of blebbistatin were examined by assaying the effects of blebbistatin on the contraction and basic cardiac etectrophysiologic parameters of Langendorff-perfused rabbit hearts, isolated rabbit right ventricle and right atrium, and single rat ventricular myocytes using conventional ECG, surface etectrograms, microelectrode recordings, and optical imaging with voltage-sensitive and Ca2+-sensitive dyes. Action potential morphology, ECG parameters, cardiac conduction, and refractoriness were determined after perfusion with 0.1-10 mu M blebbistatin.RESULTS Blebbistatin 5-10 mu M completely eliminated contraction in all cardiac preparations but did not have any effect on electrical activity, including ECG parameters, atrial and ventricular effective refractory periods, and atrial and ventricular activation patterns. Blebbistatin 10 AM had no effects on action potential morphology in rabbit cardiac tissue. Blebbistatin inhibited single cellular contraction in a dose-dependent manner with half-maximal inhibitory concentration (IC50) = 0.43 mu M, without altering the morphologies of intracellular calcium transients. The blebbistatin effect was completely reversible by simultaneous washout and photobleaching by ultraviolet tightCONCLUSION Blebbistatin is a promising novel selective excitation-contraction uncoupler that can be used for optical imaging of cardiac tissues.