Low-conductance chloride channel activated by cAMP in the epithelial cell line T84.
We have studied the modulation and pharmacological properties of two anion channels in T84 cells by recording single channel and transepithelial currents. One channel had an outwardly rectifying current-voltage I/V curve, was rarely active in cell-attached patches, and was unaffected by cAMP. The other channel had lower conductance (8.7 pS at 37 degrees C) and a more ohmic I/V relationship. Exposure to cAMP increased the probability of observing low-conductance channel activity in cell-attached patches greater than 6-fold. Extracellular DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid) or [IAA-94 (an indanyloxyacetic acid) inhibited the outward rectifier but did not affect the low-conductance channel or cAMP-stimulated transepithelial current. These results suggest the low-conductance Cl channel may contribute to apical membrane conductance during cAMP-stimulated secretion.
Tabcharani
J A
JA
Department of Physiology, McGill University, Montréal, Québec, Canada.
Low
W
W
Elie
D
D
Hanrahan
J W
JW
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D002460:Cell Line; D018118:Chloride Channels; D002712:Chlorides / Q000378:metabolism*; D000242:Cyclic AMP / Q000502:physiology*; D004553:Electric Conductivity / Q000187:drug effects; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism*; D006016:Glycolates / Q000494:pharmacology; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D008565:Membrane Proteins / Q000187:drug effects / Q000502:physiology*; D013696:Temperature
D018118:Chloride Channels; D002712:Chlorides; D006016:Glycolates; D007473:Ion Channels; D008565:Membrane Proteins; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; C015765:MK 473; D000242:Cyclic AMP; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid