Effects of the PKC inhibitors chelerythrine and bisindolylmaleimide I (GF 109203X) on delayed rectifier K+ currents
Effects of the PKC inhibitors chelerythrine and bisindolylmaleimide I (GF 109203X) on delayed rectifier K+ currents
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DOI：
10.1007/s00210-010-0584-8
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发表时间：
2011-02-01
影响因子：
3.6
通讯作者：
Nanasi, Peter P.
中科院分区：
文献类型：
--
作者：
Harmati, Gabor;Papp, Ferenc;Nanasi, Peter P.
蛋白激酶C（PKC）抑制剂是研究PKC依赖性离子通道调节的有用工具。为此，高PKC特异性是一个基本要求，排除PKC抑制剂与离子通道之间的任何直接相互作用。本文研究了两种常用的PKC抑制剂白屈菜红碱和双吲哚马来酰亚胺I对犬心室肌细胞延迟整流钾电流快、慢成分（I（Kr）和I（Ks））和人胚肾（HEK）细胞表达的人ether-A -go-go-related基因（hERG）通道的影响。在所有实验中使用全细胞形式的膜片钳技术。白屈菜红碱和bisindolylmaleimide I（均为1 μ M）抑制犬心室细胞I（Kr）。这种抑制迅速发展，表明直接的药物通道相互作用。在异源表达hERG通道的HEK细胞中，白屈菜红碱和双吲哚马来酰亚胺I以浓度依赖性方式阻断hERG电流，其EC 50值分别为0.11 +/- 0.01和0.76 +/- 0.04 μ M。白屈菜红碱和双吲哚马来酰亚胺I强烈修改门控动力学的hERG-电压依赖性的激活转向更负的电压和激活加速。双吲哚马来酰亚胺I减慢失活，但白屈菜红碱不减慢失活。双吲哚马来酰亚胺I和白屈菜红碱对I（Ks）无显著影响。观察到0.1 μ M双吲哚马来酰亚胺I或0.1 μ M PMA（PKC激活剂）对I（Kr）无显著影响，这与PKC对I（Kr）调节的显著贡献相反。可以得出结论，白屈菜红碱和双吲哚马来酰亚胺I都不适合选择性PKC阻断，因为它们对hERG通道具有直接阻断作用。
Protein kinase C (PKC) inhibitors are useful tools for studying PKC-dependent regulation of ion channels. For this purpose, high PKC specificity is a basic requirement excluding any direct interaction between the PKC inhibitor and the ion channel. In the present study, the effects of two frequently applied PKC inhibitors, chelerythine and bisindolylmaleimide I, were studied on the rapid and slow components of the delayed rectifier K+ current (I (Kr) and I (Ks)) in canine ventricular cardiomyocytes and on the human ether-A -go-go-related gene (hERG) channels expressed in human embryonic kidney (HEK) cells. The whole cell version of the patch clamp technique was used in all experiments. Chelerythrine and bisindolylmaleimide I (both 1 mu M) suppressed I (Kr) in canine ventricular cells. This inhibition developed rapidly, suggesting a direct drug-channel interaction. In HEK cells heterologously expressing hERG channels, chelerythrine and bisindolylmaleimide I blocked hERG current in a concentration-dependent manner, having EC50 values of 0.11 +/- 0.01 and 0.76 +/- 0.04 mu M, respectively. Both chelerythrine and bisindolylmaleimide I strongly modified gating kinetics of hERG-voltage dependence of activation was shifted towards more negative voltages and activation was accelerated. Deactivation was slowed by bisindolylmaleimide I but not by chelerythrine. I (Ks) was not significantly altered by bisindolylmaleimide I and chelerythrine. No significant effect of 0.1 mu M bisindolylmaleimide I or 0.1 mu M PMA (PKC activator) was observed on I (Kr) arguing against significant contribution of PKC to regulation of I (Kr). It is concluded that neither chelerythrine nor bisindolylmaleimide I is suitable for selective PKC blockade due to their direct blocking actions on the hERG channel.