Hypo-osmolar stimulation of transepithelial Cl- secretion in cultured human T84 intestinal epithelial layers

G T McEwan, C D Brown, B H Hirst, N L Simmons

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Intact epithelial monolayers of T84 human colonic adenocarcinoma cells were exposed from the basolateral surfaces to hypo-osmotic media; in responsive tissues this resulted in a transient stimulation of inward short-circuit current (SCC) to a peak of 12.9 +/- 1.5 (S.E., n = 10) microA/cm2 which declined to prestimulation values of SCC (2.1 microA/cm2) within 5 min. Exposure of T84 cells to hypo-osmotic media results in an increase in cytosolic [Ca2+]i, dependent on extracellular Ca2+ influx. The cell-swelling activated SCC is abolished upon medium Cl- replacement and by 100 microM bumetanide applied to the basal-surfaces, consistent with the inward SCC resulting from transepithelial Cl- secretion. 100 microM DIDS (4,4'-diisothiocyanantostilbene-2,2'-disulphonic acid) also abolished the cell-swelling activated increase in SCC; DIDS is without effect upon the VIP-stimulated SCC, suggesting distinct Cl- channels are involved in the two responses.
Original languageEnglish
Pages (from-to)180-3
Number of pages4
JournalBiochimica et Biophysica Acta
Issue number2
Publication statusPublished - 10 Jun 1992



  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
  • Bumetanide
  • Calcium
  • Chloride Channels
  • Chlorides
  • Culture Media
  • Cytosol
  • Epithelium
  • Humans
  • Intestine, Large
  • Membrane Potentials
  • Membrane Proteins
  • Osmolar Concentration
  • Tumor Cells, Cultured

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