Amino acid current through anion channels in cultured human glial cells
Amino acid current through anion channels in cultured human glial cells
复制标题
培养的人神经胶质细胞中通过阴离子通道的氨基酸电流
作者：
Guy Roy
在低渗介质中的体积调节期间，神经胶质细胞释放其大部分氨基酸。这些氨基酸的损失似乎是由扩散型的运输和肿胀激活的氯离子通道似乎参与介导的。该项目的目的是提供氨基酸可以通过Cl−通道扩散的直接证据。使用人神经胶质细胞系，在低渗介质中激活的Cl−电流在全细胞膜片钳中测量。为了测量氨基酸产生的电流，必须将外部溶液的pH值增加到碱性值，达到9.6和10.0，以提高这些氨基酸的阴离子形式的浓度。引入含有高浓度氨基酸（如甘氨酸、牛磺酸、谷氨酰胺和谷氨酸）的外部低渗培养基，可以使用NMDG-Cl填充的移液器测量其各自的电流-电压曲线。从反转电位，它们的渗透率比相对于氯化物进行了测定。结果发现，低分子量的氨基酸，如甘氨酸，是最具渗透性的，而较大的氨基酸，如谷氨酰胺，相对于氯化物具有较低的渗透性。具有两个羧基的氨基酸，如谷氨酸，具有低得多的渗透率。还测量了一些代谢物如乳酸盐和苹果酸盐的逆转电位以进行比较。这些结果表明，氨基酸可以通过阴离子通道扩散，并且在病理条件下这些通道的激活可能至少部分地导致所观察到的外部氨基酸的增加。
During volume regulation in hypotonic media, glial cells release a large portion of their amino acids. These amino acid losses appear to be mediated by a diffusion type of transport and a swelling-activated chloride channel seems to be involved. The objective of this project was to provide direct evidence that amino acids could diffuse through a Cl− channel. Using a human glial cell line, Cl− currents activated in hypotonic media were measured in whole-cell patch clamp. To measure the currents produced by amino acids, it was necessary to increase the pH of external solutions to basic values reaching 9.6 and 10.0 to raise the concentration of the anionic form of these amino acids. Introducing external hypotonic media containing high concentrations of amino acids, like glycine, taurine, glutamine and glutamate, it was possible to measure their respective current-voltage curves with NMDG-Cl-filled pipettes. From the reversal potentials, their permeability ratios with respect to chloride were determined. It was found that the low molecular weight amino acids, like glycine, were most permeant, while the larger ones, like glutamine, had a lower permeability with respect to chloride. The amino acids with two carboxyl groups, like glutamate, had a much lower permeability ratio. The reversal potentials for some metabolites, like lactate and malate were also measured for comparison. These results demonstrate that amino acids can diffuse through anion channels and that activation of these channels in pathological conditions could be at least partly responsible for the observed increase in external amino acids.
影响因子：
--
作者：
JACKSON, PS;STRANGE, K
通讯作者：
STRANGE, K
渗透膨胀过程中 Jurkat T 淋巴细胞的膜氯电导和电容。
影响因子：
3.4
作者：
Ross,PE;Garber,SS;Cahalan,MD
通讯作者：
Cahalan,MD