Verapamil和Mn^（2＋）对缺氧和复氧心肌细胞内Na~＋浓度的影响

Effects of verapamil and Mn^(2+)on[Na^+]_i in hypoxic and reoxygenated cardiomyocytes

采用荧光探针ＳＢＦＩ／ＡＭ结合计算机图像处理技术测定缺氧和复氧时单心肌细胞内Ｎａ＋的变化及钙通道阻滞剂Ｖｅｒａｐａｍｉｌ和Ｎａ＋－Ｃａ２＋交换抑制剂Ｍｎ２＋对其的影响。结果表明随缺氧和复氧时间的延长细胞内Ｎａ＋均增加。Ｖｅｒａｐａｍｉｌ对缺氧或复氧细胞内Ｎａ＋无影响（Ｐ＞０．０５），Ｍｎ２＋能使复氧细胞内Ｎａ＋含量增加（Ｐ＜０．０１）。本文推断Ｖｅｒａｐａｍｉｌ不是通过降低细胞内Ｎａ＋浓度而发挥保护心肌作用，特异性强的Ｎａ＋－Ｃａ２＋交换抑制剂会使复氧心肌细胞内Ｎａ＋含量增加而削弱其保护作用。

Fluorescent probe SBFI/AM combined with image processing technique was used to investigate intracellular Na+ concentration([Na+]i)alterations in various stages of hypoxic and reoxygenatedmyocytes as well as the effects of calcium channel blocker verapamil and the Na+-Ca2+ exchange inhibitor Mn2+on[Na+]i.The results indicated that [Na+]i rose gradually with the prolongation of hypoxia and reoxygenation.Verapamil had no significant effect on [Na+]i during hypoxia and reoxygenation(P>0.05). Mn2+ increased [Na+]i during reoxygenation(P<0.05).These results suggested thatthe protective effect of verapamll on cardiac myocytes were not through its action of decreasing[Na+]i and more specific Na+-Ca2+ exchange inhibitor would diminish its protective effects because of its increasing [Na+]i.