Activation of amiloride-sensitive sodium transport in C6 glioma cells.
Activation of amiloride-sensitive sodium transport in C6 glioma cells.
复制标题
C6 神经胶质瘤细胞中阿米洛利敏感的钠转运的激活。
DOI：
10.1111/j.1471-4159.1984.tb12849.x
复制
发表时间：
1984
影响因子：
4.7
通讯作者：
Benos,DJ
中科院分区：
文献类型：
--
作者：
Sapirstein,VS;Benos,DJ
我们已经在C6细胞中表征了阿米洛利敏感的Na+进入途径，该途径可以交换H+。在本报告中，我们证明了这种阳离子交换系统可以在24-36小时内通过血清去除或双丁酰环AMP诱导;然而，这些诱导模式不是累加的，只有在血清激活后才表现出来。在这些神经胶质瘤细胞中，我们发现血清的激活可以部分被特异性血清因子模拟，即，表皮生长因子和缓激肽。我们试图使用几种细胞生物探针来进一步表征这种激活过程。我们之前已经证明，该活化过程涉及钙依赖性步骤，在钙离子载体A23187存在下获得完全活化。用秋水仙碱预孵育可抑制血清激活，但用二氢细胞松弛素B预孵育则无抑制作用，表明细胞骨架参与了激活过程。激活表皮生长因子和缓激肽被认为是不受秋水仙碱，这表明其他因素必须存在于血清中，赋予秋水仙碱的敏感性。用佛波醇肉豆蔻酰乙酸酯孵育细胞导致阿米洛利敏感性转运的激活，这表明蛋白激酶C的刺激可能是激活过程的组成部分。与血清的作用不同，秋水仙碱不抑制佛波醇肉豆蔻酰乙酸酯的激活，表明这种药物以绕过细胞骨架依赖性步骤的方式起作用。由于二酰基甘油是蛋白激酶C的假定内源性激活剂，我们研究了二油基甘油的影响。发现这种磷酸化Upid周转的中间体特异性增加阿米洛利敏感性钠途径。因此，我们认为神经胶质细胞和其他细胞中的Na+-H+交换可能与磷脂周转和钙流动密切相关，这两个过程是神经胶质细胞酸化和离子稳态不可或缺的。
We have characterized, in C6 cells, an amiloride‐sensitive Na+entry pathway that can exchange for H+. In this report we demonstrate that this cation‐exchange system can be induced within 24–36 h by either serum removal or by dibutyryl cyclic AMP; however, these modes of induction are not additive and are manifest only after activation by serum. In these glioma cells we found that activation by serum can be mimicked in part by specific serum factors, i.e., epidermal growth factor and bradykinin. We attempted to characterize this activation process further using several cell biologic probes. We had previously shown that that activation process involves a calcium‐dependent step with full activation obtained in the presence of the calcium iono‐phore A23187. The activation by serum was inhibited by preincubation with colchicine but not with dihydrocyto‐chalasin B, suggesting a cytoskeletal involvement in the activation process. Activation by epidermal growth factor and bradykinin was found to be unaffected by colchicine, suggesting that other factors must be present in serum that confer sensitivity to colchicine. Incubation of the cells with phorbol myristoyl acetate results in the activation of amiloride‐sensitive transport, suggesting that stimulation of protein kinase C may be integral to the activation process. Unlike the effects of serum, activation by phorbol myristoyl acetate is not inhibited by colchicine, indicating that this drug works in a way that bypasses the cytoskeletal‐dependent step. Since diacyl‐glycerol is the presumed endogenous activator of protein kinase C., we studied the effects of dioleylglycerol. This intermediate of phosphoUpid turnover was found to increase specifically the amiloride‐sensitive sodium pathway. We feel therefore that Na+‐H+exchange in glial cells as well as in other cells may be tightly linked to phospholipid turnover and to calcium flux and that these two processes are integral to glial cell acidification and ion homeostasis.