兔近端小管曲部基底外侧膜囊泡中的钾通道。

Potassium channels in basolateral membrane vesicles from pars convoluta of rabbit proximal tubule.

作者信息

Jacobsen C, Blokkebak-Poulsen J, Sheikh M I

机构信息

Institute of Medical Biochemistry, University of Aarhus, Denmark.

出版信息

FEBS Lett. 1990 Sep 3;269(2):315-8. doi: 10.1016/0014-5793(90)81183-o.

DOI:10.1016/0014-5793(90)81183-o

PMID:2401355

Abstract

The characteristics of 86Rb+ fluxes through conductive channels in basolateral-membrane vesicles isolated from pars convoluta of rabbit proximal tubule were investigated. In KCl loaded vesicles a transient accumulation of 86Rb+ was observed which was inhibited by BaCl2. The accumulation was driven by an electrical diffusion potential, as shown in experiments using membrane vesicles loaded with Li2SO4 and an outwardly directed Li+ gradient established with a Li(+)-ionophore. The vesicles containing the channel showed a cation selectivity with the order K+ = Rb+ much greater than Li+ greater than or equal to Na+ greater than choline+. The 86Rb+ flux was dependent on intravesicular Ca2+. Increasing concentrations of Ca2+ gradually decreased the 86Rb+ uptake.

摘要

研究了从兔近端小管曲部分离的基底外侧膜囊泡中通过导电通道的86Rb+通量的特征。在加载KCl的囊泡中观察到86Rb+的瞬时积累，该积累被BaCl2抑制。如使用加载有Li2SO4的膜囊泡以及用Li(+)离子载体建立的外向Li+梯度的实验所示，这种积累是由电扩散电位驱动的。含有该通道的囊泡表现出阳离子选择性，顺序为K+ = Rb+远大于Li+大于或等于Na+大于胆碱+。86Rb+通量依赖于囊泡内的Ca2+。Ca2+浓度增加会逐渐降低86Rb+的摄取。