Calcium mobilization by cadmium or decreasing extracellular Na+ or pH in coronary endothelial cells.
Calcium mobilization by cadmium or decreasing extracellular Na+ or pH in coronary endothelial cells.
复制标题
镉动员钙或降低冠状动脉内皮细胞的细胞外 Na 或 pH 值。
DOI：
10.1016/0014-4827(91)90152-k
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发表时间：
1991
影响因子：
3.7
通讯作者：
Smith,JB
中科院分区：
文献类型：
--
作者：
Dwyer,SD;Zhuang,Y;Smith,JB
用胆碱替代细胞外Na+可使冠状动脉内皮细胞胞质游离Ca 2+（[Ca 2 +]i）瞬时增加5倍以上。去除外部Na+刺激~（45）Ca ~（2+）流出~4倍，内流~1.7倍。外排的刺激是独立的细胞外Ca ~（2+）和渗透性Na ~+替代物。[Ca ~（2+）] i和~（45）Ca ~（2+）流出量的增加可能是由于贮存Ca ~（2+）的释放，而不是通过Na ~+ → Ca ~（2+）交换引起的Ca ~（2+）内流。镉或降低外部，而不是细胞内，pH值瞬时增加[Ca 2 +]i。Cd 2+和一些其他二价金属也刺激45 Ca 2+流出。各金属离子对外排的促进作用大小顺序为Cd ~（2+）> Co ~（2+）> Ni ~（2+）> Fe ~（2+）> Mn ~（2+）。在无Zn ~（2+）存在的情况下，先用Zn ~（2+）孵育细胞，可强烈抑制Cd ~（2+）（pH 6）对~（45）Ca ~（2+）外排的刺激，并抑制Na ~+的清除，而不影响ATP对~（45）Ca ~（2+）外排的刺激。这些发现支持了这样的假设，即某些微量金属或降低外部Na+或pH通过刺激细胞表面“受体”触发储存的Ca 2+的释放。
Replacing extracellular Na+with choline transiently increased cytoplasmic free Ca2+([Ca2+]i) more than 5-fold in coronary endothelial cells. Removing external Na+stimulated45Ca2+efflux ~4-fold and influx ~1.7-fold. The stimulation of efflux was independent of extracellular Ca2+and the osmotic Na+substitute. The release of stored Ca2+, rather than Ca2+influx via Na+Ca2+exchange, probably causes the increase in [Ca2+]iand45Ca2+efflux. Cadmium or decreasing external, not intracellular, pH transiently increased [Ca2+]i. Cd2+and some other divalent metals also stimulated45Ca2+efflux. The potency order of the metals that stimulated efflux was Cd2+> Co2+> Ni2+> Fe2+> Mn2+. Incubating the cells with Zn2+prior to assaying efflux in the absence of Zn2+strongly inhibited the stimulation of45Ca2+efflux by Cd2+, pH 6, and the removal of external Na+without affecting the stimulation of efflux by ATP. These findings support the hypothesis that certain trace metals or decreasing external Na+or pH trigger the release of stored Ca2+by stimulating a cell surface “receptor.”