Neonatal rat cardiac fibroblasts express three types of voltage-gated K+ channels:: regulation of a transient outward current by protein kinase C
Neonatal rat cardiac fibroblasts express three types of voltage-gated K+ channels:: regulation of a transient outward current by protein kinase C
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DOI：
10.1152/ajpheart.01195.2007
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发表时间：
2008-02-01
影响因子：
4.8
通讯作者：
Zhang, Jining
中科院分区：
文献类型：
--
作者：
Walsh, Kenneth B.;Zhang, Jining
心脏成纤维细胞通过与相关心肌细胞的机械、化学和电学相互作用来调节心肌发育。本研究的目的是鉴定和表征新生大鼠心室成纤维细胞的电压门控性K+(Kv)通道。应用膜片钳技术的全细胞排列技术，在培养的成纤维细胞上测量了三种电压门控性外向钾电流。大多数细胞表达瞬时外向钾电流(I-to)，该电流在-40 mV正电位时激活，在去极化电压阶跃时部分失活。抗心律失常药氟卡胺(100 MU M)和BaCl2(1 MM)对I-TO有抑制作用，而4-氨基吡啶(4-AP；0.5和1 mM)对I-TO无影响。少数细胞表达被4-AP强烈阻断的两种不同的延迟整流性K+电流[快-钾电流(I-KF)和慢钾电流(I-Ks)]中的一种。应用佛波酯刺激蛋白激酶C(PKC)，抑制I-to，但对I-KF和I-Ks无影响。免疫印迹分析显示成纤维细胞中存在Kv1.4、Kv1.2、Kv1.5和Kv2.1α亚基，但不存在Kv4.2或Kv1.6α亚基。4-AP可抑制血管紧张素II诱导的细胞内钙动员。因此，新生儿心脏成纤维细胞至少表达三种不同的Kv通道，这些通道可能参与这些细胞的电/化学信号。
Cardiac fibroblasts regulate myocardial development via mechanical, chemical, and electrical interactions with associated cardiomyocytes. The goal of this study was to identify and characterize voltage-gated K+ (Kv) channels in neonatal rat ventricular fibroblasts. With the use of the whole cell arrangement of the patch-clamp technique, three types of voltage-gated, outward K+ currents were measured in the cultured fibroblasts. The majority of cells expressed a transient outward K+ current (I-to) that activated at potentials positive to -40 mV and partially inactivated during depolarizing voltage steps. I-to was inhibited by the antiarrhythmic agent flecainide (100 mu M) and BaCl2 (1 mM) but was unaffected by 4-aminopyridine (4-AP; 0.5 and 1 mM). A smaller number of cells expressed one of two types of kinetically distinct, delayed-rectifier K+ currents [I-K fast (I-Kf) and I-K slow (I-Ks)] that were strongly blocked by 4-AP. Application of phorbol 12-myristate 13-acetate, to stimulate protein kinase C (PKC), inhibited I-to but had no effect on I-Kf and I-Ks. Immunoblot analysis revealed the presence of Kv1.4, Kv1.2, Kv1.5, and Kv2.1 alpha-subunits but not Kv4.2 or Kv1.6 alpha-subunits in the fibroblasts. Finally, pretreatment of the cells with 4-AP inhibited angiotensin II-induced intracellular Ca2+ mobilization. Thus neonatal cardiac fibroblasts express at least three different Kv channels that may contribute to electrical/chemical signaling in these cells.