影响离体大鼠心肌细胞和蛋白重组脂质体Na^+-Ca^(2+)交换的因素

FACTORS AFFECT Na^+-Ca^(2+) EXCHANGE IN RAT'S CARDIOMYOCYTES AND PROTEIN-RECONSTITUTED LIPOSOMES

本工作在离体成年大鼠心室肌细胞和狗心肌肌膜Na^+-Ca^(2+)交换蛋白重组脂质体上,发现预先用哇巴因孵育细胞使细胞内Na^+浓度升高或降低细胞外Na^+浓度均使细胞及脂质体的Na^+-Ca^(2+)交换增加。Mn^(2+)对细胞和脂质体的Na^+-Ca^(2+)交换呈剂量依赖性的抑制作用;异搏定则无明显影响;花生四烯酸对Na^+-Ca^(2+)交换有激活作用;过氧化氢引起膜脂质过氧化后,显著促进脂质体的Na^+-Ca^(2+)交换,并呈时间和剂量依赖性。

Rat's Ca-resistant ventricular myocytes and reconstituted liposomes of canine cardiac sarcolemma were used in analysing factors affecting Na^+-Ca^(2+) exchange system. Decrease in extracellular(extravesicular) Na^+ or increase in intracellular Na^+ by inhibition of the Na^+-K^+-ATPase with ouabain stimulated the Na^+-Ca^(2+) exchange. Mn^(2+), an antagonist of Na^+-Ca^(2+) exchange, dose-dependently inhibited the Na^+-dependent Ca^(2+) uptake. However, verapamil had no effect on it. Arachidonic acid and lipid peroxides caused by incubation withH_O_2 significantly stimulated Na^+-Ca^(2+) exchange in a dose-dependent fashin.