Functional and molecular characterizations of chloride channels in rat pleural mesothelial cells.
The purposes of the present study were to clarify whether some Cl(-) channels exist in rat pleural mesothelial cells, and to investigate functional and molecular characteristics of these channels. Electrophysiological recordings were performed at room temperature using the whole-cell configuration of the patch-clamp technique. We could observe outwardly rectifying Cl(-) currents in rat pleural mesothelial cells under isotonic conditions. These currents exhibited time-dependent inactivation at potential over +60 mV and were inhibited by NPPB. It suggests the presence of voltage-dependent Cl(-) channels. Moreover, we observed the currents activated under hypotonic conditions. Their biophysical and pharmacological properties exhibited as follows; moderate outward rectification of whole-cell currents; time-dependent inactivation at large positive potential; anion selectivity with a type-I Eisenman's permeability sequence (I(-)>Br(-)>Cl(-)>F(-)>glutamate(-)); inhibited by NPPB. These properties are consistent with volume-regulated chloride channels (VRCCs), even though molecular identity of VRCCs could not have been determined, the molecular expressions of mRNA of the Cl(-) channels ClC-2, ClC-3, pI(Cln), MDR1 were confirmed. The properties of VRCCs in the pleural mesothelial cells were consistent with those of ClC-3 channels, and different from those of ClC-2. Therefore, these results suggest that ClC-3 might contribute to the modulation of VRCCs in rat pleural mesothelial cells.
Yoshise
Yuya
Y
Department of Comparative Pathophysiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
Ito
Koichi
K
Tsubone
Hirokazu
H
Kuwahara
Masayoshi
M
D000818:Animals; D018118:Chloride Channels / Q000378:metabolism*; D002712:Chlorides / Q000494:pharmacology; D004553:Electric Conductivity; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D009579:Nitrobenzoates / Q000494:pharmacology; D009997:Osmotic Pressure; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013379:Substrate Specificity
D018118:Chloride Channels; D002712:Chlorides; D009579:Nitrobenzoates; D012333:RNA, Messenger; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid