CONTROL BY INTERNAL CALCIUM OF MEMBRANE PERMEABILITY TO SODIUM AND POTASSIUM
CONTROL BY INTERNAL CALCIUM OF MEMBRANE PERMEABILITY TO SODIUM AND POTASSIUM
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DOI：
10.1113/jphysiol.1971.sp009445
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发表时间：
1971-01-01
影响因子：
5.5
通讯作者：
WHITTAM, R
中科院分区：
文献类型：
--
作者：
ROMERO, PJ;WHITTAM, R
1.研究了人红细胞膜内钙离子浓度与钠、钾离子渗透性的关系.新鲜的红细胞含有很少的钙，但在老化耗尽ATP后，它们从林格氏溶液中摄取钙。入口不受外部钠和钾的影响，但具有明显的pH依赖性。当提供能量时，钙负载细胞通过饱和过程主动挤出钙，这也不受跨膜钠和钾分布的影响。钙泵的活性足以维持生理条件下的低浓度.提高代谢不良细胞的内部钙引起细胞钾的损失，其大于伴随的钠增益。当提供ATP时，这些变化被逆转。外部钙没有影响。钠和钾渗透性的增加通过同时添加氟化物而增强，并且碘乙酸盐的增加更是如此。这些抑制剂对膜通透性没有影响，除非钙也存在。肌苷通过允许更多的钙进入细胞，增强了氟和碘乙酸引起钾流失的作用。结果表明，人体红细胞膜对钠和钾的渗透性受内部钙的调节，而内部钙又受利用ATP的钙泵的控制。
1. A study has been made of the relationship between the concentration of internal calcium and the permeability of human red cell membranes to sodium and potassium.2. Fresh red cells contain very little calcium, but after being depleted of ATP by ageing they took up calcium from Ringer solution. The entry was unaffected by external sodium and potassium but was markedly pH dependent. When supplied with energy, calcium‐loaded cells actively extruded calcium by a saturable process which was also unaffected by the distribution of sodium and potassium across the membranes. The activity of the calcium pump was sufficient to maintain the low internal concentration found under physiological conditions.3. Raising internal calcium in metabolically poor cells caused a loss of cell potassium which was greater than the concomitant sodium gain. These changes were reversed when ATP was supplied. External calcium had no effect. The increase in permeability to sodium and potassium was enhanced by the simultaneous addition of fluoride, and, even more so, of iodoacetate. These inhibitors had no effect on membrane permeability unless calcium was also present. Inosine potentiated the action of fluoride and iodoacetate in causing potassium loss, by allowing more calcium to enter the cells.4. The results suggest that the permeability of human red cell membranes to sodium and potassium is regulated by internal calcium, which in turn is controlled by a calcium pump that utilizes ATP.