Journal
BRAZILIAN JOURNAL OF MEDICAL AND BIOLOGICAL RESEARCH
Volume 38, Issue 1, Pages 133-140Publisher
ASSOC BRAS DIVULG CIENTIFICA
DOI: 10.1590/S0100-879X2005000100020
Keywords
water absorption and secretion; aquaporins; osmotic and hydrostatic gradients; T84 cells
Categories
Ask authors/readers for more resources
T84 is an established cell line expressing an enterocyte phenotype whose permeability properties have been widely explored. Osmotic permeability (P-OSM), hydraulic permeability (P-HYDR) and transport-associated net water fluxes (J(W)-transp), as well as short-circuit current (I-SC), transepithelial resistance (R-T), and potential difference (DeltaV(T)) were measured in T84 monolayers with the following results: P-OSM 13 +/- 0.1 cm.x(-1) x 10(-3) P-HYDR 0.27 +/- 0.02 cm.s(-1): R-T 2426 +/- 109 Omega.cm(2), and DeltaV(T) 1.31 +/- 0.38 mV. The effect of 50 muM 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazol-2-one (DCEBIO), a net Cl- secretory agent, on T84 cells was also studied. We confirm the reported important increase in I-SC induced by DCEBIO which was associated here with a modest secretory DeltaJ(W)-transp. The present results were compared with those reported using the same experimental approach applied to established cell lines originating from intestinal and renal epithelial cells (Caco-2, LLC-PK1 and RCCD-1). No clear association between P-HYDR and R-T could be demonstrated and high P-HYDR values were observed in an electrically tight epithelium, supporting the view that a water leaky barrier is not necessarily an electrically leaky one. Furthermore, the modest secretory DeltaJ(W)-transp was not consistent with previous results obtained with RCCD-1 cells stimulated with vasopressin (absorptive fluxes) or with T84 cells secreting water under the action of Escherichia coli heat stable enterotoxin. We conclude that, while the presence of aquaporins is necessary to dissipate an external osmotic gradient, coupling between water and ion transport cannot be explained by a simple and common underlying mechanism.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available