Fura-2探针对希土Y^(3+)跨PC12细胞膜行为研究

RESEARCH ON TRANSMEMBRANE BEHAVIORS OF Y 3+ BY Fura 2 FLUORESENT PROBE

使用ＡＲ－ＭＩＣ－ＣＭ阳离子测定系统，发展Ｆｕｒａ－２荧光测定技术，将其应用于测定细胞内游离希土离子Ｙ３＋，并以此研究了Ｙ３＋跨ＰＣ１２细胞（大鼠嗜铬细胞瘤细胞）膜的行为。结果表明：在模拟细胞内各离子组分，ｐＨ＝７．０５的溶液中，测得表观解离常数为４．５ｐｍｏｌ·Ｌ－１。对于ＰＣ１２细胞，静息条件下Ｙ３＋不能跨越细胞膜进入胞内。与钙离子通道相关的ＫＣｌ和去甲肾上腺素均不能刺激希土Ｙ３＋过膜。用Ｏｕａｂａｉｎ（哇巴因）使胞内Ｎａ＋超载后，Ｙ３＋可过膜进入细胞内，且过膜量与胞外Ｙ３＋浓度和胞内Ｎａ＋超载程度有一定的浓度依赖关系，提示Ｙ３＋可以经由Ｎａ＋／Ｙ３＋交换机制过膜而进入细胞内。

By the use of the applied research cation measurement system, Fura 2 fluorescence measurment method was forwarded to detect the intracellular Y 3+ concentration, and used for investigating the transmembrane behaviors of Y 3+ to PC12 cells An apparent dissociation constant of Y 3+ Fura 2 was 4 5p mol·L -1 in solutions simulating intracellular ionic composition, with pH 7 05 Y 3+ ions could not enter PC12 cell under the normal condition, and also could not enter the cell via the calcium channel stimulated by KCl and norpinephrine However Y 3+ ions entered PC12 cell after Na + ions within the cell were overloaded using Ouabain Amonut of Y 3+ entering P12 cell were related to both outer cellular Y 3+ concentration and intracellular overloaded Na + concentration It is suggested that Y 3+ enter the cell in Na + Y 3+ exchanging mechanism