Coupled sodium-calcium transport in cultured chick heart cells.
Coupled sodium-calcium transport in cultured chick heart cells.
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培养鸡心脏细胞中钠钙耦合转运。
DOI：
10.1152/ajpcell.1986.250.3.c442
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Lieberman,M
中科院分区：
文献类型：
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作者：
Murphy,E;Wheeler,DM;LeFurgey,A;Jacob,R;Lobaugh,LA;Lieberman,M
在培养的鸡胚心脏细胞中，细胞外Na（Nao）和Ca（Cao），细胞内Na（Nai）和Ca，细胞外pH值和膜电位的改变导致Na和Ca含量的变化与肌膜Na-Ca交换一致。24 Na外排测量显示了一个大的哇巴因不敏感的组件，其中三分之一被抑制去除曹。在无钠溶液中孵育细胞导致总细胞Ca快速增加1.5至2倍，并保持升高至少15分钟。暴露于小于或等于20 mM的Nao 15分钟的细胞变得最大负载Ca，而当Nao值大于20 mM时，Ca负载量急剧下降。与Ca积累有关。在Na-K泵抑制过程中（10（-4）M哇巴因），Na最初升高2- 3倍至低于其平衡值的水平;然后，将Cao从1.25 mM降低至0.75 mM，持续30分钟，导致Nai升高26%，而将Cao从1.25 mM升高至2.7 mM，导致Nai相对于其电化学梯度下降25%。这些数据与Na-K泵抑制期间Na-Ca交换维持Nai一致。在哇巴因（10（-4）M）的存在下，钙摄取到细胞内细胞器，例如，线粒体，这是由总细胞钙的增加以及线粒体基质颗粒的出现，这是定性的X-射线分析显示含有钙建议。虽然基质颗粒也发生在线粒体在无钠孵育，他们不包含可检测到的量的钙时，在相同的条件下检查的固定和分析。
In cultured embryonic chick heart cells, alterations of extracellular Na (Nao) and Ca (Cao), intracellular Na (Nai) and Ca, extracellular pH, and membrane potential resulted in changes in Na and Ca contents that were consistent with sarcolemmal Na-Ca exchange. 24Na efflux measurements revealed a large ouabain-insensitive component, one-third of which was inhibited by removal of Cao. Incubating the cells in Na-free solution resulted in a rapid, 1.5- to 2-fold increase in total cell Ca that remained elevated for at least 15 min. Cells exposed for 15 min to Nao less than or equal to 20 mM became maximally loaded with Ca, whereas Ca loading fell off sharply at values of Nao greater than 20 mM. The movement of Na against its electrochemical gradient was shown to be associated with Ca accumulation. During Na-K pump inhibition (in 10(-4) M ouabain), Na initially rose 2- to 3-fold to a level below its equilibrium value; then, lowering Cao for 30 min from 1.25 to 0.75 mM caused a 26% elevation in Nai, whereas raising Cao from 1.25 to 2.7 mM resulted in a 25% fall in Nai against its electrochemical gradient. These data are consistent with Nai being maintained by a Na-Ca exchange during Na-K pump inhibition. In the presence of ouabain (10(-4) M), Ca uptake into intracellular organelles, e.g., mitochondria, was suggested by an increase in total cell Ca as well as the occurrence of mitochondrial matrix granules, which were shown qualitatively by X-ray analysis to contain Ca. Although matrix granules also occurred in mitochondria during Na-free incubation, they did not contain detectable amounts of Ca when examined under identical conditions of fixation and analysis.