Whole-cell Cl- currents in a human peripheral airway epithelial cell line.
We have used the whole-cell patch-clamp technique to identify and characterize Cl- currents in a cell line derived from human peripheral airway epithelium (NCI-H-441-4). The permeability sequence and relative selectivity for different anions was Br- (1.4) approximately I- (1.3) > Cl- (1.0) > F- (0.6) > gluconate (0.4) > glutamate (0.2). The current-voltage relationship displayed rectification in the outward direction. Diphenylamine-2-carboxylate (10(-4) M) applied intracellularly blocked the outward-rectified current, while extracellularly applied diphenylamine-2-carboxylate had no effect on Cl- current. This current was also blocked by extracellularly applied 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB), with an estimated IC50 of 15.2 microM. Dibutyryl-cyclic AMP (10(-4) M) increased outward current, whereas pretreatment with 100 ng/mL pertussis toxin almost completely abolished the Cl- current. Pertussis toxin inhibition of this current could be partially reversed by dialysis of the cell interior with the activated alpha i-2 subunit of Gi protein. This cell line provides an opportunity to study directly the regulation of Cl- channels in cells derived from the peripheral human lung airways.
Wang
X
X
Respiratory Research Division, Hospital for Sick Children, Toronto, ON, Canada.
Fedorko
L
L
Marunaka
Y
Y
O'Brodovich
H
H
D003994:Bucladesine / Q000494:pharmacology; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004594:Electrophysiology; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000502:physiology; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects; D009579:Nitrobenzoates / Q000494:pharmacology; D037342:Pertussis Toxin; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D062367:ortho-Aminobenzoates / Q000494:pharmacology
D018118:Chloride Channels; D009579:Nitrobenzoates; D010566:Virulence Factors, Bordetella; D062367:ortho-Aminobenzoates; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D003994:Bucladesine; C001209:fenamic acid; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins