Zhang Y, Zhong N, Zhou Z N
Shanghai Institute of Physiology, Chinese Academy of Sciences, People's Republic of China.
Life Sci. 2000 Oct 6;67(20):2465-71. doi: 10.1016/s0024-3205(00)00832-8.
Although it has been reported that intermittent hypoxia had the anti-arrhythmia effect, little is known about the effects on the action potential (AP) and contraction of papillary muscle, as well as the mechanism of anti-arrhythmia. The purpose of present study is to observe the effects of intermittent hypoxia on action potential and contraction of papillary muscle in rat left ventricle simultaneously using conventional intracellular microelectrode and contraction recording. The effects of intermittent hypoxia on AP and contraction during ischemic solution perfusion were also investigated. After exposed to intermittent hypoxia (six hours daily) for 42 days (IH42), duration (APD20) of 20%, 50% (APD50) and 90% (APD90) repolarization of AP prolonged significantly compared with animals in control (Con). Effective refractory period (ERP) in IH42 also prolonged significantly. Perfused with mimic ischemic solution, the changes of electric and mechanical activities in IH42 and in 28 days exposure to intermittent hypoxia (IH28) were much smaller than that in Con and IH14. The result of the study suggested that intermittent hypoxia prolonged the APD and ERP, offered the resistance against the ischemic damage on myocardium, which may be the electrophysiological basis of the anti-arrhythmia of intermittent hypoxia.
虽然已有报道称间歇性低氧具有抗心律失常作用，但关于其对动作电位（AP）和乳头肌收缩的影响以及抗心律失常机制却知之甚少。本研究的目的是使用传统的细胞内微电极和收缩记录方法，同时观察间歇性低氧对大鼠左心室乳头肌动作电位和收缩的影响。还研究了在缺血溶液灌注期间间歇性低氧对AP和收缩的影响。在每天暴露于间歇性低氧（每天6小时）42天后（IH42），与对照组（Con）动物相比，AP复极化20%（APD20）、50%（APD50）和90%（APD90）的持续时间显著延长。IH42组的有效不应期（ERP）也显著延长。用模拟缺血溶液灌注时，IH42组以及暴露于间歇性低氧28天（IH28）组的电活动和机械活动变化比Con组和IH14组小得多。研究结果表明，间歇性低氧延长了APD和ERP，对心肌缺血损伤具有抵抗作用，这可能是间歇性低氧抗心律失常的电生理基础。
