培养的牛色素性睫状上皮的钾离子电导和电生性钠钾转运

K+-conductance and electrogenic Na+/K+ transport of cultured bovine pigmented ciliary epithelium.

作者信息

Helbig H, Korbmacher C, Wiederholt M

机构信息

Institut für Klinische Physiologie, Klinikum Steglitz der Freien Universität Berlin, Federal Republic of Germany.

出版信息

J Membr Biol. 1987;99(3):173-86. doi: 10.1007/BF01995698.

DOI:10.1007/BF01995698

PMID:2826792

Abstract

Using intracellular microelectrode technique, we investigated the changes in membrane voltage (V) of cultured bovine pigmented ciliary epithelial cells induced by different extracellular solutions. (1) V in 213 cells under steady-state conditions averaged -46.1 +/- 0.6 mV (SEM). (2) Increasing extracellular K+ concentration [( K+]o) depolarized V. Addition of Ba2+ could diminish this response. (3) Depolarization on doubling [K+]o was increased at higher [K+]o (or low voltage). (4) Removing extracellular Ca2+ decreased V and reduced the V amplitude on increasing [K+]o. (5) V was pH sensitive. Extra- and intracellular acidification depolarized V; alkalinization induced a hyperpolarization. V responses to high [K+]o were reduced at acidic extracellular pH. (6) Removing K+o depolarized, K+o readdition after K+ depletion transiently hyperpolarized V. These responses were insensitive to Ba2+ but were abolished in the presence of ouabain or in Na+-free medium. (7) Na+ readdition after Na+ depletion transiently hyperpolarized V. This reaction was markedly reduced in the presence of ouabain or in K+-free solution but unchanged by Ba2+. It is concluded that in cultured bovine pigmented ciliary epithelial cells K+ conductance depends on Ca2+, pH and [K+]o (or voltage). An electrogenic Na+/K+-transport is present, which is stimulated during recovery from K+ or Na+ depletion. This transport is inhibited by ouabain and in K+- or Na+-free medium.

摘要

我们采用细胞内微电极技术，研究了不同细胞外溶液诱导培养的牛色素性睫状上皮细胞的膜电压（V）变化。（1）213个细胞在稳态条件下的V平均值为-46.1±0.6 mV（标准误）。（2）细胞外K⁺浓度[K⁺]o增加使V去极化。添加Ba²⁺可减弱此反应。（3）在较高[K⁺]o（或低电压）时，[K⁺]o加倍时的去极化增强。（4）去除细胞外Ca²⁺使V降低，并降低了[K⁺]o增加时的V幅度。（5）V对pH敏感。细胞外和细胞内酸化使V去极化；碱化诱导超极化。在酸性细胞外pH下，V对高[K⁺]o的反应降低。（6）去除细胞外K⁺使V去极化，K⁺耗尽后重新添加K⁺使V短暂超极化。这些反应对Ba²⁺不敏感，但在哇巴因存在或无Na⁺培养基中被消除。（7）Na⁺耗尽后重新添加Na⁺使V短暂超极化。在哇巴因存在或无K⁺溶液中，此反应明显减弱，但Ba²⁺对此无影响。结论是，在培养的牛色素性睫状上皮细胞中，K⁺电导取决于Ca²⁺、pH和[K⁺]o（或电压）。存在一种生电Na⁺/K⁺转运，在从K⁺或Na⁺耗尽恢复过程中受到刺激。这种转运受到哇巴因以及在无K⁺或无Na⁺培养基中的抑制。