SPATIAL BUFFERING OF LIGHT-EVOKED POTASSIUM INCREASES BY RETINAL MULLER (GLIAL) CELLS
SPATIAL BUFFERING OF LIGHT-EVOKED POTASSIUM INCREASES BY RETINAL MULLER (GLIAL) CELLS
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DOI：
10.1126/science.2785716
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发表时间：
1989-05-05
期刊：
影响因子：
56.9
通讯作者：
NEWMAN, EA
中科院分区：
文献类型：
--
作者：
KARWOSKI, CJ;LU, HK;NEWMAN, EA
中枢神经系统细胞外钾离子浓度的活动依赖性变化可能部分受到神经胶质细胞钾离子空间缓冲电流的调节。通过测量两栖动物眼杯中光诱发的钾变化来评估视网膜中空间缓冲的作用。玻璃体液中增加的钾的幅度降低至约。10%的50微摩尔钡，而钾的增加在内部网状层基本上没有变化。 玻璃体钾反应的降低是用钾电流流经视网膜主要胶质细胞Mueller细胞的数值模型精确模拟的。钡还显著增加Mueller细胞的输入电阻并阻断Mueller细胞产生的M波，表明钡阻断Mueller细胞的钾通道。因此，在视网膜内光诱发的钾增加之后，通过流经Mueller细胞的钾电流，钾从视网膜大量转移到玻璃体液。
Activity-dependent variations in extracellular potassium concentration in the central nervous system may be regulated, in part, by potassium spatial buffering currents in glial cells. The role of spatial buffering in the retina was assessed by measuring light-evoked potassium changes in amphibian eyecups. The amplitude of potassium increased in the vitreous humor was reduced to .apprx. 10 percent by 50 micromolar barium, while potassium increases in the inner plexiform layer were largely unchanged. The decrease in the vitreal potassium response was accurately simulated with a numerical model of potassium current flow through Mueller cells, the principal glial cells of the retina. Barium also substantially increased the input resistance of Mueller cells and blocked the Mueller cell-generated M-wave, indicating that barium blocks the potassium channels of Mueller cells. Thus, after a light-evoked potassium increase within the retina, there is a substantial transfer of potassium from the retina to the vitreous humor by potassium current flow through Mueller cells.