EFFECT OF VOLUME CHANGES ON A POTASSIUM CURRENT IN RABBIT CORNEAL EPITHELIAL-CELLS
EFFECT OF VOLUME CHANGES ON A POTASSIUM CURRENT IN RABBIT CORNEAL EPITHELIAL-CELLS
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DOI：
10.1152/ajpcell.1993.264.5.c1238
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发表时间：
1993-05-01
影响因子：
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通讯作者：
RAE, J
中科院分区：
文献类型：
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作者：
FARRUGIA, G;RAE, J
来自兔角膜上皮细胞的膜片钳记录发现了一个大电导（在对称的150 mM KCl中有167 pS）的K通道，这是整个细胞电流的主要贡献者（J. L. Rae和G. Farrugia）。j .会员。生物学。129:81-87,1992)。我们在此报告通过细胞渗透压和/或体积的变化对该通道的调节。用低渗溶液（225或150 mosM）交换浴液会导致细胞肿胀和K电流的选择性激活（分别增加126 +/- 86和273 +/- 184%）。高渗溶液变化（380 mosM）导致细胞收缩和K电流失活（44.2 +/- 21%）。在穿孔贴片实验中，随着移液管细胞内溶液氯离子浓度（50 mM）的增加（增加127 +/- 63%），细胞体积和全细胞电流也有类似的增加。这些变化伴随着静息膜电压的明显变化。我们得出结论，这些细胞中的K通道可以响应细胞渗透压或体积的改变，从而导致整个细胞电流和静息电压的变化。
Patch-clamp recordings from rabbit corneal epithelial cells have identified a large-conductance (167 pS in symmetrical 150 mM KCl) K channel that is the major contributor to the whole cell current (J. L. Rae and G. Farrugia. J. Membr. Biol. 129: 81-87, 1992). We report here on the regulation of this channel by changes in cellular osmolality and/or volume. Exchanging the bath solution with a hyposmotic (225 or 150 mosM) solution resulted in cellular swelling and selective activation of the K current (126 +/- 86 and 273 +/- 184% increase, respectively). Hyperosmotic solution changes (380 mosM) resulted in cell shrinkage and deactivation of the K current (44.2 +/- 21% decrease). Similar increases in the cell volume and whole cell current were observed on increasing (in perforated patch experiments) the chloride ion concentration (50 mM) in the pipette intracellular solution (127 +/- 63% increase). These changes were accompanied by marked shifts in the resting membrane voltage. We conclude that the K channels in these cells can respond to alteration in cellular osmolality or volume, resulting in changes in the whole cell current and resting voltage.