活性氧对心肌细胞膜ATP酶活性的影响

The effect of activated oxygen on myocardial membrane ATPase

本实验观察了羟自由基发生系统(Fe^(2+)+H_2O_2)及过氧化氢对心肌细胞膜ATP酶活性的影响。证实羟自由基可造成心肌细胞膜ATP酶活性下降及膜脂质过氧化反应增强,其作用可被羟自由基消除剂甘露醇所对抗。过氧化氢对心肌细胞膜ATP酶也有一定直接抑制作用,但若过氧化氢通过自由基反应产生了羟自由基,则可造成心肌细胞膜ATP酶活性的更大幅度下降。

Lately, many studies indicated that ischemia followed by reperfusion may result in an increased production of activated oxygen. By now, most of them address the subject of lipid peroxidation but not activated oxygen on membrane protein. In our experiment, we found that the hydroxyl radical which was generated by ferrous salt plus hydrogen peroxide caused the inhibition of ATPase activity accompanying the increase production of malondialdehyde (MDA), and mannitol was effective on reversing this inhibition. Although hydrogen peroxide had an inhibitory effect on myocardial membrane ATPase activity in a dose-response fashion, mannitol had no influence on this inhibition, the extent of ATPase activity inhibition was substantially greater for hydroxyl radical than for hydrogen peroxide. Our present study demonstrated that activated oxygen could cause not only the membrane lipid peroxidation but also the decrease of membrane ATPase activity.