The mechanism of electrodiffusive K+ transport in leaky epithelia and some of its consequences for anion transport
The mechanism of electrodiffusive K+ transport in leaky epithelia and some of its consequences for anion transport
复制标题
渗漏上皮中电扩散钾离子传输的机制及其对阴离子传输的一些影响
DOI：
10.1007/bf02181468
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
M. Cour
中科院分区：
文献类型：
--
作者：
T. Zeuthen;O. Christensen;J. Bærentsen;M. Cour
用双腔离子选择性微电极在突然更换脑室浴液的条件下，对黄斑蜜环菌脉络丛上皮细胞的心室膜进行了探测。通过增加K+的外部浓度或应用哇巴因诱导的瞬态表明，K+穿过心室膜的被动运动是电扩散的，可以用Goldmann方程和24×10−6cm s−1的常数渗透率（PK）来描述。在不同的稳定状态下，PK是不同的;当细胞通过将沐浴溶液中的CO2从1%增加到5%而酸化半个pH单位时，PK降低到13×10−6cm s−1。从浸浴溶液中去除Cl−可使PK增加50%，而速尿对Cl−转运的减少并不改变PK，因此K+的主要运动与Cl−运动无关。由于电扩散渗透性（PHCO 3），细胞的去极化导致细胞HCO 3 −浓度增加，其值估计为17×10−6cm s−1。
The ventricular membrane of the epithelium from the choroid plexus ofNecturus maculosuswas probed with double-barrelled ion-selective microelectrodes while the ventricular bathing solution was changed abruptly. The transient states induced by increasing the external concentration of K+or by the application of ouabain showed that the passive movements of K+across the ventricular membrane were electro-diffusive and could be described by the Goldmann equation and one constant permeability (PK) of 24×10−6cm s−1. The passive efflux was balanced by a ouabain-sensitive influx.PKwas different in different steady states; when the cell was acidified by half a pH unit by increasing CO2in the bathing solutions from 1 to 5%, thenPKdecreased to 13×10−6cm s−1. Removal of Cl−from the bathing solution increasedPKby 50% and reduction of Cl−transport by furosemide did not alterPK, consequently major movements of K+were independent of Cl−movements. Depolarizations of the cell caused an increase in the cellular HCO3−concentration due to an electrodiffusive permeability (PHCO3), the value of which was estimated to 17×10−6cm s−1.