Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison, WI 53792, USA.
Antioxid Redox Signal. 2013 Feb 1;18(4):432-68. doi: 10.1089/ars.2011.4234. Epub 2012 Aug 16.
Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation.
活性氧（ROS）与各种人类疾病有关，人们相当关注其生理作用的研究。如果细胞抗氧化防御机制失效，各种 ROS 在 线粒体中合成并在细胞质中积累。这种 ROS 合成和抗氧化防御系统的关键平衡被称为细胞的氧化还原系统。各种心血管疾病也受到氧化还原的不同程度的影响。ROS 通过不同的细胞途径，对心肌细胞功能、电生理学和药理学既有有害作用，也有保护作用。ROS 的功能主要取决于合成的 ROS 的类型和数量。虽然文献清楚地表明 ROS 对心脏收缩力的影响，但它们对心脏兴奋性的影响相对较小。心脏兴奋性取决于携带各种去极化或复极化电流的各种心肌肌浆网或线粒体离子通道的功能，这些电流也维持细胞离子平衡。ROS 以不同程度改变这些离子通道的功能，通过影响细胞静息电位和心脏动作电位的形态来决定兴奋性。因此，氧化还原平衡调节心脏兴奋性，在病理调节下，可能改变动作电位传播引起心律失常。了解氧化还原如何影响细胞兴奋性可能为各种心律失常的预防或治疗提供新的思路。本综述将重点关注氧化还原与心脏兴奋的研究。
