Characterisation of volume-activated ion transport across epithelial monolayers of human intestinal T84 cells

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

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Abstract

The effects of hypo-osmolarity upon transepithelial ion transport in human intestinal cell layers have been investigated. Exposure of the basal-lateral surfaces to hypo-osmotic media resulted in a transient stimulation of inward short-circuit current (Isc). This transient stimulation of inward current by hypo-osmotic media was abolished by 100 mumol/l 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS). After prestimulation of inward Isc by vasoactive intestinal peptide (VIP) or by combinations of carbachol and prostaglandin E1, hypo-osmotic exposure of the basal-lateral surfaces resulted in a further transient stimulation of Isc. The stimulation of Isc in these conditions was largely insensitive to DIDS inhibition. Exposure of the basal-lateral surfaces to hypo-osmotic media resulted in a stimulation of loop-diuretic-insensitive 86Rb efflux across the basal-lateral surfaces. In addition, hypo-osmotic exposure of T84 cells is also associated with an increase in cytosolic Ca2+. It is concluded that the effects of hypo-osmotic exposure of T84 cells on secretory Isc are consistent with the activation of a DIDS-sensitive apical Cl- conductance and a basal-lateral K+ conductance. With prior activation of inward Isc by VIP via a cAMP-activated DIDS-insensitive apical Cl- conductance, augmentation of the secretory current by hypo-osmotic exposure is likely to result primarily from increased basal-lateral K+ current and loop-diuretic-sensitive Cl- uptake.
Original languageEnglish
Pages (from-to)213-20
Number of pages8
JournalPflugers Archiv : European Journal of Physiology
Volume423
Issue number3-4
Publication statusPublished - May 1993

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Keywords

  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
  • Biological Transport
  • Calcium
  • Carbachol
  • Cells, Cultured
  • Chlorides
  • Electric Conductivity
  • Epithelium
  • Humans
  • Hypotonic Solutions
  • Intestines
  • Ions
  • Kinetics
  • Osmolar Concentration
  • Prostaglandins E
  • Rubidium Radioisotopes
  • Vasoactive Intestinal Peptide

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