Title: Separate swelling- and Ca2+-activated anion currents in Ehrlich ascites tumor cells
Authors: Pedersen, S F ×
Prenen, Jean
Droogmans, Guillaume
Hoffmann, E K
Nilius, Bernd #
Issue Date: Jun-1998
Series Title: The Journal of membrane biology. vol:163 issue:2 pages:97-110
Abstract: A Ca2+-activated (ICl,Ca) and a swelling-activated anion current (ICl,vol) were investigated in Ehrlich ascites tumor cells using the whole cell patch clamp technique. Large, outwardly rectifying currents were activated by an increase in the free intracellular calcium concentration ([Ca2+]i), or by hypotonic exposure of the cells, respectively. The reversal potential of both currents was dependent on the extracellular Cl- concentration. ICl,Ca current density increased with increasing [Ca2+]i, and this current was abolished by lowering [Ca2+]i to <1 nm using 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid (BAPTA). In contrast, activation of ICl,vol did not require an increase in [Ca2+]i. The kinetics of ICl,Ca and ICl,vol were different: at depolarized potentials, ICl,Ca as activated in a [Ca2+]i- and voltage-dependent manner, while at hyperpolarized potentials, the current was deactivated. In contrast, ICl,vol exhibited time- and voltage-dependent deactivation at depolarized potentials and reactivation at hyperpolarized potentials. The deactivation of ICl, vol was dependent on the extracellular Mg2+ concentration. The anion permeability sequence for both currents was I- > Cl- > gluconate. ICl,Ca was inhibited by niflumic acid (100 micron), 5-Nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, 100 micron) and 4, 4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS, 100 micron), niflumic acid being the most potent inhibitor. In contrast, ICl,vol was unaffected by niflumic acid (100 micron), but abolished by tamoxifen (10 micron). Thus, in Ehrlich cells, separate chloride currents, ICl,Ca and ICl,vol, are activated by an increase in [Ca2+]i and by cell swelling, respectively.
ISSN: 0022-2631
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Physiology Section (-)
Laboratory of Ion Channel Research
Department of Cellular and Molecular Medicine - miscellaneous
× corresponding author
# (joint) last author

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