Cation transport and membrane potential properties of primary astroglial cultures from neonatal rat brains
Cation transport and membrane potential properties of primary astroglial cultures from neonatal rat brains
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新生大鼠脑原代星形胶质细胞培养物的阳离子转运和膜电位特性
DOI：
10.1016/0006-8993(79)90470-0
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发表时间：
1979
期刊：
影响因子：
2.9
通讯作者：
R. S. Bourke
中科院分区：
文献类型：
--
作者：
H. Kimelberg;C. Bowman;S. Biddlecome;R. S. Bourke
本文介绍了K+和Na+的含量和运输的原代单层培养的新生大鼠脑，被认为是主要由星形胶质细胞。测量了添加哇巴因后阳离子含量的净变化，以及使用86 Rb+作为K+标记物和22 Na+作为Na+标记物的稳态通量。结果发现，细胞保持传统的阳离子动态平衡模式，K+的净流出通过哇巴因敏感（Na+K）泵介导的主动吸收和主动挤出平衡的Na+净吸收来平衡。这些过程保持内部测量的K+：Na+比率为12-25：1。细胞通常是扁平的，但添加DBcAMP使它们变圆并形成许多突起，外观类似于体内星形胶质细胞。用~（86）Rb ~+测定的K ~+稳态水平也降低了15- 30%，而对~（86）Rb ~+和~（22）Na ~+摄取的初始速率没有影响。在35°C、外部K+浓度（[K+]0）为4.5 mM时，各组细胞的膜电位平均值为-65 mV至-75 mV。研究了单个细胞和细胞组的膜电位对[K+] 0的依赖性。当K+浓度大于10-20 mM K+时，[K+] 0每10倍变化的电位斜率为55-57 mV，当K+浓度低于此值时，电位斜率偏离此值。这表明这些细胞对K+以外的离子具有一定的渗透性。假设Na+是影响膜电位的唯一其他离子，计算出Na+的渗透性比K+小约30倍。基于对也用DBcAMP处理的细胞的运输实验的Na+和K+渗透性的估计，获得了类似的结果。将从这些细胞获得的结果与其他培养的神经胶质细胞和体内神经胶质细胞的结果进行比较。我们的结论是，在本研究中使用的培养细胞的膜电位显示最接近的相似性，到目前为止，在体内的神经胶质细胞，因为它们是大的和负的，主要是由K+。然而，培养的细胞具有不同的性质，从那些在体内的神经胶质细胞的一些研究中报道的显示自由渗透性的离子以外的K+。
This paper describes K+and Na+content and transport in primary monolayer cultures from dissociated newborn rat brains, considered to consist predominantly of astroglial cells. Net changes in cation content after addition of ouabain, and steady state fluxes using86Rb+as a marker for K+and22Na+as a marker for Na+, were measured.The results found indicate that the cells maintained a conventional pattern of cation homeostasis with net efflux of K+being balanced by its active uptake and net uptake of Na+balanced by active extrusion mediated by a ouabain sensitive (Na+K) pump. These processes maintained internal measured K+:Na+ratios of 12–25:1. The cells were normally flat but addition of DBcAMP caused them to round up and form numerous processes, an appearance resembling that of astroglial cells in vivo. DBcAMP treatment also reduced the steady state levels of K+measured with86Rb+by 15–30%, and had no effect on initial rates of86Rb+and22Na+uptake.The membrane potentials of cells treated with DBcAMP were studied, since only these were easily impaled. The membrane potentials of separate groups of cells gave means ranging from—65 to—75 mV at 35°C, at an external K+concentration ([K+]0) of 4.5 mM. The dependence of the membrane potentials of individual cells and groups of cells on [K+]0was studied. The slope of the potential per 10-fold change in [K+]0was 55–57 mV, at concentrations of K+greater than 10–20 mM K+, and diverged from this slope at concentrations below this. This shows that these cells had some permeability to ions other than K+. Assuming that Na+was the only other ion affecting the membrane potential, it was calculated that the permeability to Na+was about 30 times less than K+. A similar result was obtained based on estimates of Na+and K+permeability from transport experiments on cells also treated with DBcAMP.The results obtained from these cells are compared to those found for other cultured glial cells and glial cells in vivo. We conclude that the membrane potentials of the cultured cells used in the present study show the closest resemblance so far to glia in vivo, since they are large and negative and are determined mainly by K+. However, the cultured cells have different properties from those reported in some studies for glial cells in vivo by showing free permeability to ions other than K+.