Depolarizing effects of catecholamines in quiescent sheep cardiac Purkinje fibers.
Depolarizing effects of catecholamines in quiescent sheep cardiac Purkinje fibers.
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儿茶酚胺对静止绵羊心脏浦肯野纤维的去极化作用。
DOI：
10.1152/ajpheart.1986.251.5.h1056
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Fozzard,HA
中科院分区：
文献类型：
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作者：
Terris,S;Wasserstrom,JA;Fozzard,HA
异丙肾上腺素可逆地使静止的绵羊心脏浦肯野纤维去极化，这与其在许多可兴奋组织中的超极化效应形成了鲜明对比。这种去极化被阻断β1-肾上腺素能受体的药物抑制。河豚毒素和维拉帕米对异丙肾上腺素引起的去极化无影响。铯可使异丙肾上腺素引起的去极化降低74%。在电压钳下测量的称为IF的电流分量的激活与电压的依赖关系被异丙肾上腺素沿去极化方向移动。没有证据支持对其他组织提出的异丙肾上腺素刺激Na+-K+泵的建议。这些数据表明，在静止的绵羊浦肯野纤维中，异丙肾上腺素引起的去极化反应了起搏器电流的激活。
Isoproterenol reversibly depolarizes quiescent sheep cardiac Purkinje fibers, in contrast to its reported hyperpolarizing effect in many excitable tissues. The depolarization is inhibited by drugs that block beta 1-adrenergic receptors. Tetrodotoxin and verapamil have no effect on the isoproterenol-induced depolarization. Cesium reduced the isoproterenol-induced depolarization by 74%. The voltage dependency of activation of a current component called If, measured under voltage clamp, was shifted in the depolarizing direction by isoproterenol. No evidence was found to support the suggestion made for other tissues that the Na+-K+ pump is stimulated by isoproterenol. These data suggest that in quiescent sheep Purkinje fibers the isoproterenol-induced depolarization reflects activation of a pacemaker current.