INTRACELLULAR CL- ACTIVITY AND CELLULAR CL- PATHWAYS IN CULTURED HUMAN AIRWAY EPITHELIUM
INTRACELLULAR CL- ACTIVITY AND CELLULAR CL- PATHWAYS IN CULTURED HUMAN AIRWAY EPITHELIUM
复制标题
DOI：
10.1152/ajpcell.1989.256.5.c1033
复制
发表时间：
1989-05-01
影响因子：
--
通讯作者：
BOUCHER, RC
中科院分区：
文献类型：
--
作者：
WILLUMSEN, NJ;DAVIS, CW;BOUCHER, RC
研究了人鼻上皮细胞（一种主要吸收Na+的近端气道上皮细胞）的Cl-转运。细胞内Cl-活性（aClc）和电位跨顶端（Va）和基底侧（Vb）膜测量与双管，Cl-选择性微电极，以表征Cl-流的驱动力，通过每个膜。在对照条件下（双侧Krebs-碳酸氢盐林格氏液），Va为-26.1 +/- 1.2 mV，Vb为-36.2 +/- 1.2 mV，aCL（c）为42.7 +/- 2.0 mM（n = 34），表明Cl-在顶膜上接近电化学平衡，但在基底侧膜上显著高于平衡。管腔[Cl-]从120 mM降至3 mM，aClc从42.7 +/- 4.0 mM降至27.0 +/- 3.5 mM，Va去极化，顶端膜电阻分数（fRa）和跨上皮电阻（Rt）增加。布美他尼使aClc降低10 mM，而不影响电参数。丝氨酸[Cl-]从120 mM降至3 mM导致Vb快速降低、fRa降低和Rt增加。此外，丝氨酸[Cl-]降低导致aClc从45.5 +/- 2.5 mM缓慢降低至31.1 +/- 4.2 mM，布美他尼可抑制该降低。数据与以下结论一致：1）Cl-通过传导途径转运穿过顶膜; 2）Cl-通过电沉默的布美他尼敏感共转运系统和次要传导途径转运穿过基底外侧膜。
Cl- transport was studied in human nasal epithelium, a predominantly Na+-absorbing proximal airway epithelium. Intracellular Cl- activity (aClc) and the electrical potentials across the apical (Va) and basolateral (Vb) membranes were measured with double-barreled, Cl- -selective microelectrodes to characterize the driving forces for Cl- flow across each membrane. Under control conditions (bilateral Krebs-bicarbonate Ringer), Va was -26.1 +/- 1.2 mV, Vb was -36.2 +/- 1.2 mV, and aCL(c) was 42.7 +/- 2.0 mM (n = 34), indicating that Cl- is near electrochemical equilibrium across the apical membrane but significantly above equilibrium across the basolateral membrane. Reduction of luminal [Cl-] from 120 to 3 mM reduced aClc from 42.7 +/- 4.0 to 27.0 +/- 3.5 mM, depolarized Va, and increased fractional apical membrane resistance (fRa) and transepithelial resistance (Rt). Serosal bumetanide reduced aClc by 10 mM without affecting electrical parameters. Reduction of serosal [Cl-] from 120 to 3 mM resulted in a rapid decrease in Vb, a decrease in fRa and an increase in Rt. Also, serosal [Cl-] reduction led to a slow decrease in aClc rom 45.5 +/- 2.5 to 31.1 +/- 4.2 mM) that could be inhibited by bumetanide. The data are consistent with the following conclusions: 1) Cl- is transported across the apical membrane through a conductive pathway; and 2) Cl- is translocated across the basolateral membrane by an electrically silent bumetanide-sensitive cotransport system and by a minor conductive path.