Volume regulation during recovery from chronic hypertonicity in brain glial cells.
Volume regulation during recovery from chronic hypertonicity in brain glial cells.
复制标题
脑胶质细胞慢性高渗恢复过程中的容量调节。
DOI：
10.1152/ajpcell.1992.263.2.c412
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Morrison,R
中科院分区：
文献类型：
--
作者：
Strange,K;Morrison,R
当暴露于高渗介质时，大鼠 C6 神经胶质细胞通过摄取电解质经历快速调节体积增加（5-10 分钟）。长期处于高渗状态（超过 8 小时），积聚的电解质部分被肌醇替代。肌醇积累是由 Na(+) 依赖性肌醇运输的上调引起的。当长期适应高渗 NaCl 培养基的 C6 细胞恢复到等渗条件时，肌醇水平在 18-24 小时内从 478 nmol/mg 蛋白质缓慢下降至对照值（117 nmol/mg 蛋白质）。肌醇损失部分是通过与摄取机制不同的途径流出到外部介质而发生的。激光光散射测量表明，在这些实验条件下，调节体积减小（RVD）很慢。相比之下，急性暴露于高渗状态的细胞会发生膨胀，然后当返回到等渗介质时会经历快速且几乎完全的 RVD。这些结果表明，在慢性高渗应激恢复过程中，缓慢的肌醇损失是 RVD 的速率限制。缓慢的肌醇损失和 RVD 可能是由于外排机制的缓慢周转和/或高渗刺激的肌醇摄取途径的缓慢下调所致。
Rat C6 glial cells undergo rapid regulatory volume increase (5-10 min) via electrolyte uptake when exposed to a hypertonic medium. With chronic exposure to hypertonicity (greater than 8 h), accumulated electrolyte is replaced partly by inositol. Inositol accumulation is brought about by upregulation of Na(+)-dependent inositol transport. When C6 cells acclimated chronically to hypertonic NaCl medium were returned to isotonic conditions, inositol levels dropped slowly from 478 nmol/mg protein towards control values (117 nmol/mg protein) in 18-24 h. Inositol loss occurred in part by efflux to the external medium via a pathway distinct from the uptake mechanism. Laser light-scattering measurements demonstrated that regulatory volume decrease (RVD) is slow under these experimental conditions. In contrast, cells exposed acutely to hypertonicity swell and then undergo a rapid and nearly complete RVD when returned to isotonic medium. These results suggest that slow inositol loss is rate limiting for RVD during recovery from chronic hypertonic stress. The slow inositol loss and RVD may be due to slow turnover of the efflux mechanism and/or slow downregulation of the hypertonically stimulated inositol uptake pathway.