心肌缺血再灌注损伤时细胞核被膜钙泵活性特征的研究

目的　研究心肌缺血再灌注损伤时Ca2 + 、ATP、ADP和AMP对细胞核被膜钙泵 (Ca2 + ATPase)活性的调节。方法　采用大鼠心肌缺血再灌注模型 ,密度梯度分离纯化细胞核 ,定磷法测定Ca2 + ATPase活性。结果　与正常大鼠相比 ,缺血再灌注损伤动物血浆MDA和FFA显著升高 (P <0 0 1) ;细胞核Ca2 + ATPase活性下降 ,对Ca2 + 亲和力降低 ;ADP、AMP对核Ca2 + ATPase活性的影响明显减弱 ;ATP对Ca2 + ATPase的作用在 ATP]小于 1 0mmol L时 ,与正常细胞Ca2 + AT Pase活性无显著差异 ,浓度增至 2 0mmol L时 ,活性低于正常细胞 ,ATP浓度继续增加 ,核Ca2 + ATPase活性快速增加。结论　心肌缺血再灌注损伤时Ca2 + 、ATP、ADP、AMP对心肌细胞核Ca2 + ATPase活性的影响发生了明显改变 ,其病理生理意义值得进一步探讨。

Characteristics of myocardial nuclear Ca2+-ATPase after ischemia-reperfusion injury in rats

Objective To study the regulatory effects of Ca 2+ , ATP, ADP and AMP on myocardial nuclear Ca 2+ ATPase activity after ischemia reperfusion injury Methods The model of myocardial ischemia reperfusion injury was established in rats Myocardial nuclei were purified using sucrose density gradient centrifugation The activity of Ca 2+ ATPase was measured with ascertaining phosphate Results Compared with the control, plasma levels of MDA and FFA after myocardial ischemia reperfusion injury increased significantly ( P <0 01) The effects of ATP and ADP on activity of myocardial nuclear Ca 2+ ATPase decreased markedly ( P <0 01) There was no difference in Ca 2+ ATPase activity when ATP concentration was lower than 1 0 mmol/L However, when ATP concentration reached 2 0 mmol/L, Ca 2+ ATPase activity was lower than that of the control Ca 2+ ATPase activity rose dramatically when ATP concentration kept on increasing Conclusion The effects of Ca 2+ , ATP, ADP and AMP on nuclear Ca 2+ ATPase activity have altered markedly after myocardial ischemia reperfusion injury