Mechanism of cell swelling of HeLa cells in an isosmotic Na(+)-free, high-K+ medium: study on the K+ transport pathways.
The K+ content and the free Ca2+ concentration ([Ca2+]c) in HeLa cells began to increase after a latent period following medium change to an isosmotic Na(+)-free, high-K+ medium in the presence of 10-100 microM ouabain. These increases were accompanied by cell swelling, and stimulated by the addition of 1 microM ionomycin, whereas treatment with 1 mM quinine significantly inhibited the net K+ uptake. [Ca2+]c was slightly decreased, but the K+ uptake was unaffected in the Ca(2+)-free, high-K+ medium. However, when [Ca2+]c was extremely reduced by preloading 5 microM BAPTA-AM, the K+ uptake decreased to a level attained in the presence of quinine. Addition of DIDS and substitution with NO3- or SCN- for medium Cl- inhibited the K+ uptake to similar extents, and their effects were less strong than that of quinine. Substitution of medium Cl- with an impermeable anion gluconate completely inhibited the K+ uptake. Therefore, we conclude that cell swelling in the high-K+ medium is associated with K+ uptake mediated in greater part by quinine-sensitive and in smaller part by -insensitive pathway. The former pathway depends on cellular Ca2+ and its major component is Cl(-)-dependent, whereas the latter is independent of the Ca2+ and unselective for anions.
Kaku
M
M
Department of Physiology, School of Medicine, University of Tokushima, Japan.
Ikehara
T
T
Yamaguchi
H
H
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D048429:Cell Size / Q000187:drug effects; D003470:Culture Media; D004533:Egtazic Acid / Q000031:analogs & derivatives; D006367:HeLa Cells; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology*; D011803:Quinine / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology*; D013997:Time Factors
D003470:Culture Media; D007473:Ion Channels; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D004533:Egtazic Acid; D012964:Sodium; D011803:Quinine; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D011188:Potassium; D002118:Calcium