Characteristics of an amiloride-sensitive sodium entry pathway in cultured rodent glial and neuroblastoma cells.
Characteristics of an amiloride-sensitive sodium entry pathway in cultured rodent glial and neuroblastoma cells.
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培养的啮齿动物胶质细胞和神经母细胞瘤细胞中阿米洛利敏感的钠进入途径的特征。
DOI：
10.1002/jcp.1041160213
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发表时间：
1983
影响因子：
5.6
通讯作者：
Sapirstein,VS
中科院分区：
文献类型：
--
作者：
Benos,DJ;Sapirstein,VS
我们研究了阿米洛利敏感性钠内流进入C6胶质瘤、NIE和NB 2A神经母细胞瘤细胞系的诱导。在对数生长后期，在10%胎牛血清存在下连续生长的细胞显示约25-30 nmol/mg蛋白/min的Na+内流; < 5%的该流量被阿米洛利抑制。去除血清24 h后，总Na+内流减少至15-20 nmol/mg蛋白/min。将血清重新加入孵育培养基后，总Na+内流增加（取决于细胞类型），2 min内增加20-400%。Na+内流增加表示阿米洛利敏感性Na+转运增加，具有明显的K′，通过在血清剥夺后的不同时间加入血清，确定需要4小时观察到阿米洛利敏感性Na+通量的可检测增加。因此，血清去除导致阿米洛利转运系统的诱导，然而，其保持潜伏直到血清重新引入培养基。加入5 μg/ml放线菌酮可阻断Na+转运的增加，表明从头蛋白质合成介导了这种血清剥夺诱导的Na+转运增加。此外，抑制从头脂质合成的0.1 mM芬氟拉明也阻止了这种运输活动的诱导，这表明，一个协调的脂质和蛋白质的合成是必需的表达的钠转运网站。我们还发现，这种血清刺激的Na+内流没有饱和Na+浓度，高达140 mM。此外，在常用的抑制剂的被动Na+进入上皮组织，只有阿米洛利能够抑制这种运输系统在这些神经细胞系。
We have studied the induction of an amiloride‐sensitive sodium influx into C6 glioma, NIE, and NB2A neuroblastoma cell lines. In late log phase, cells grown continuously in the presence of 10% fetal calf serum showed Na+influxes of approximately 25–30 nmol/mg protein min; < 5% of this flux was inhibited by amiloride. Removal of serum for 24 h caused a decrease in the total Na+influx to 15–20 nmol/mg protein/min. Upon readdition of serum to the incubation medium, there was an increase in total Na+influx, depending on the cell type, of 20–400% within 2 min. This increment in Na+influx represented an increase in amiloride‐sensitive Na+transport with an apparent K′, of 0.4 mM. By adding serum back at various times after serum deprivation, it was determined that 4 h was required to observe a detectable increase in the amiloride‐sensitive Na+flux. Thus, serum removal results in the induction of the amiloride transport system which, however, remains latent until the reintroduction of serum to the medium. Addition of 5 μg/ml of cycloheximide blocked the increase in Na+transport, indicating that de novo protein synthesis mediated this serum deprivation–induced increase in Na+transport. Moreover, inhibition of de novo lipid synthesis by 0.1 mM fenfluramine also blocked the induction of this transport activity, suggesting that a coordinated synthesis of lipid and protein is required for the expression of this sodium transport site. We have also found that this serum stimulated Na+influx did not saturate with Na+concentration, up to 140 mM. Also, among commonly used inhibitors of passive Na+entry into epithelial tissues, only amiloride was capable of inhibiting this transport system in these neural cell lines.