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本实验观察了外源性自由基对大鼠左室乳头肌细胞电生理活动的影响。实验发现,(1)活性氧OH~-、O_2~-、H_2O_2均能抑制心肌细胞动作电位振幅(APA)。其中,OH~+组由给药前的110.5±11.8降至98.0±10.4mV,H_2O_2组由112.3±13.2降至99.0±13.6mV,O_2~-组由117.2±14.5降至103.8±13.2mV(P<0.05),(2)OH~+与H_2O_2能降低动作电位的0相上升最大速率(V_(max)),给药前后相比均有显著性差异(P<0.05)。0_2~-与OH~-、H_2O_2不一样,它增加V_(max)(P<0.05);(3)OH~+组还降低静息电位(RP),而H_2O_2组与O_2~-组尽管亦减小其RP,但给药前后相比无显著性差别。三种活性氧成分均不影响动作电位时程。自由基清除剂过氧化氢酶可对抗自由基降低APA、V_(max)等的抑制效应,起到保护作用。实验结果提示心肌缺血再灌注性心律失常原因之一可能与自由基改变心肌细胞电生理活动有关。
The experiment observed the effect of exogenous free radical on electrophysiological activity of left ventricular papillary muscle cells in rats. The results showed that: (1) OH ~ -, O_2 ~ - and H_2O_2 of reactive oxygen species could inhibit cardiomyocyte action potential amplitude (APA). Among them, the OH ~ + group decreased from 110.5 ± 11.8 to 98.0 ± 10.4mV before administration, from 112.3 ± 13.2 to 99.0 ± 13.6mV in H2O2 group, and decreased from 117.2 ± 14.5 to 103.8 ± 13.2mV in O_2 ~ (P <0.05). (2) OH ~ + and H_2O_2 could decrease the maximal rate of 0 phase rising of action potential (V max), and there was significant difference before and after administration (P <0.05). 0 2 ~ - was not the same as OH ~ -, H_2O_2, which increased V max (P <0.05); (3) OH ~ + group also reduced resting potential (RP); while H_2O_2 and O_2 ~ Reduce its RP, but no significant difference before and after administration. None of the three reactive oxygen species affected the action potential duration. Free radical scavenger catalase against free radicals reduce APA, V max (max) inhibitory effect, play a protective effect. The experimental results suggest that one of the causes of myocardial ischemia-reperfusion arrhythmia may be related to the change of electrophysiological activity of cardiomyocytes by free radicals.