Opening mitoKATP increases superoxide generation from complex I of the electron transport chain
Opening mitoKATP increases superoxide generation from complex I of the electron transport chain
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DOI：
10.1152/ajpheart.00272.2006
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发表时间：
2006-11-01
影响因子：
4.8
通讯作者：
Garlid, Keith D.
中科院分区：
文献类型：
--
作者：
Andrukhiv, Anastasia;Costa, Alexandre D.;Garlid, Keith D.
开放线粒体ATP敏感性K+通道（mitoK（ATP））增加心肌细胞中活性氧（ROS）的水平。这种ROS的增加对于心肌保护对抗缺血再灌注损伤是必要的;然而，线粒体K（ATP）依赖性刺激ROS产生的机制尚不清楚。我们研究了ROS生产的悬浮液中的离体大鼠心脏和肝脏线粒体，使用荧光探针，是敏感的过氧化氢。当线粒体被K-ATP通道开放剂二氮嗪或cromakalim处理时，它们的ROS产生增加了40- 50%，这种作用被5-羟基癸酸阻断。ROS的产生表现出对缬氨霉素浓度的双相依赖性，在缬氨霉素浓度下产生峰值，其催化与K-ATP通道开放剂相同的K+流入。ROS的产生降低与较高浓度的缬氨霉素和所有浓度的经典质子泳解偶联剂。我们的研究表明，活性氧的增加是由于特别是K+流入基质，并介导的伴随基质碱化。Myxothiazol刺激mitoK（ATP）依赖的ROS产生，而鱼藤酮没有影响。这表明超氧化物来源于电子传递链的复合物I（NADH：泛醌氧化还原酶）。
Opening the mitochondrial ATP-sensitive K+ channel (mitoK(ATP)) increases levels of reactive oxygen species (ROS) in cardiomyocytes. This increase in ROS is necessary for cardioprotection against ischemia-reperfusion injury; however, the mechanism of mitoK(ATP)-dependent stimulation of ROS production is unknown. We examined ROS production in suspensions of isolated rat heart and liver mitochondria, using fluorescent probes that are sensitive to hydrogen peroxide. When mitochondria were treated with the K-ATP channel openers diazoxide or cromakalim, their ROS production increased by 40-50%, and this effect was blocked by 5-hydroxydecanoate. ROS production exhibited a biphasic dependence on valinomycin concentration, with peak production occurring at valinomycin concentrations that catalyze about the same K+ influx as K-ATP channel openers. ROS production decreased with higher concentrations of valinomycin and with all concentrations of a classical protonophoretic uncoupler. Our studies show that the increase in ROS is due specifically to K+ influx into the matrix and is mediated by the attendant matrix alkalinization. Myxothiazol stimulated mitoK(ATP)-dependent ROS production, whereas rotenone had no effect. This indicates that the superoxide originates in complex I ( NADH: ubiquinone oxidoreductase) of the electron transport chain.