Whole cell patch clamping of ciliary epithelial cells during anisosmotic swelling.
Whole cell patch clamping of ciliary epithelial cells during anisosmotic swelling.
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不等渗肿胀过程中睫状上皮细胞的全细胞膜片钳。
DOI：
10.1152/ajpcell.1992.262.2.c501
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Civan,MM
中科院分区：
文献类型：
--
作者：
Yantorno,RE;Carre,DA;Coca-Prados,M;Krupin,T;Civan,MM
不等渗的细胞肿胀会引发源自人类无色素睫状上皮的细胞系的调节体积减少（RVD）。细胞体积的测量表明 RVD 反映了 K+ 和/或 Cl- 通道的激活。我们已经开始通过全细胞膜片钳来表征假定的通道。通过改变外部 K+ 和 Cl- 浓度并添加 20-50 µM 奎尼丁或 1 mM Ba2+ 获得的结果表明，在基线等渗条件下，K+ 电导对总膜电导 (GT) 贡献很大，而 Cl- 电导贡献很小。将外部渗透压降低 20-50% 可逆且可重复地将 GT 提高一个数量级。从离子取代和通道阻滞剂奎尼丁和 5-硝基-2-(3-苯基丙氨基)-苯甲酸盐获得的数据表明，大部分低渗引起的电导反映了静态 Cl(-) 通道活性。当细胞内游离 Ca2+ 浓度为 10 或 200 nM 时，新 K(+) 通道活性的贡献很小。我们得出结论，浴液低渗引发的 RVD 主要反映了 Cl(-) 通道活性的增加。
Anisosmotic cell swelling triggers a regulatory volume decrease (RVD) in cell lines derived from human nonpigmented ciliary epithelium. Measurements of cell volume have indicated that the RVD reflects activation of K+ and/or Cl- channels. We have begun to characterize the putative channels by whole cell patch clamping. The results obtained by altering the external K+ and Cl- concentrations and by adding 20-50 microM quinidine or 1 mM Ba2+ indicate that K+ conductances contribute substantially and Cl- conductances contribute very little to the total membrane conductance (GT) under baseline isotonic conditions. Reducing the external osmolality by 20-50% reversibly and reproducibly increased GT by an order of magnitude. Data obtained from ion substitutions and the channel blockers quinidine and 5-nitro-2-(3-phenylpropylamino)-benzoate indicate that most of the hypotonicity-induced conductance reflects stationary Cl(-)-channel activity. The contribution of new K(+)-channel activity was small at intracellular free Ca2+ concentrations of 10 or 200 nM. We conclude that the RVD triggered by bath hypotonicity primarily reflects increased Cl(-)-channel activity.