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本研究采用蔗糖梯度离心法制各大鼠心肌细胞膜，观察溶血磷脂酸（ ＬＰＡ）对心肌细胞膜 Ｎａ~＋－Ｃａ~(２＋)交换的影 响。结果发现ＬＰＡ（１～２０ｎｍｏｌ／Ｌ）呈剂量依赖性和时间依赖性刺激Ｎａ~＋一Ｃａ~（２＋）交换活性增加。Ｇｐｐ（ＮＨ）ｐ呈剂量依赖 性替代ＬＰＡ刺激的Ｎａ~＋－Ｃａ~(２＋)交换活性；ＰＴＸ可抑制ＬＰＡ对Ｎａ~＋－Ｃａ~(２＋)交换的激活；Ｇｅｎｉｓｔｅｉｎ，Ｐｒｏｐｒａｎｏｌｏｌ，Ｐｒａｚｏｓｉｎ，Ａｔｒｏｐｉｎｅ，Ｌｏｓａｒｔａｎ，ＢＱ１２３和磷脂酰胆碱对ＬＰＡ诱导的Ｎａ~＋－Ｃａ~２＋交换活性无影响，而磷脂酰丝氨酸可增加对照和ＬＰＡ 两组的 Ｎａ~＋－Ｃａ~(２＋)交换活性。这些结果表明 ＬＰＡ可通过 ＰＴＸ敏感的 Ｇ蛋白刺激大鼠心肌细胞膜 Ｎａ~＋－Ｃａ~(２＋)交换活性。
In this study, myocardial cell membrane was prepared by sucrose gradient centrifugation and the effect of lysophosphatidic acid (LPA) on Na ~ + -Ca ~ (2+) exchange in myocardial cells was observed. The results showed that LPA (1 ~ 20nmol / L) increased the Na ~ + -Ca2 + exchange activity in a dose-dependent and time-dependent manner. Gpp (NH) p dose-dependently replaced LPA-stimulated Na ~ + -Ca ~ (2+) exchange activity; PTX inhibited LPA activation of Na ~ + -Ca 2+ exchange; Genistein, Propranolol, Prazosin, Atropine , Losartan, BQ123 and phosphatidylcholine had no effect on LPA-induced Na ~ + -Ca ~ 2 + exchange activity, while phosphatidylserine increased Na ~ + -Ca ~ (2+) exchange activity in both LPA and control groups. These results indicate that LPA can stimulate Na ~ + -Ca ~ (2+) exchange activity in rat cardiac myocytes through PTX-sensitive G protein.