Document Detail


Damage to the gastric epithelium activates cellular bicarbonate secretion via SLC26A9 Cl(-)/HCO(3)(-).
MedLine Citation:
PMID:  20413716     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Gastric surface pH (pH(o)) transiently increases in response to focal epithelial damage. The sources of that increase, either from paracellular leakage of interstitial fluid or transcellular acid/base fluxes, have not been determined. Using in vivo microscopy approaches we measured pH(o) with Cl-NERF, tissue permeability with intravenous fluorescent-dextrans to label interstitial fluid (paracellular leakage), and gastric epithelial intracellular pH (pH(i)) with SNARF-5F (cellular acid/base fluxes). In response to two-photon photodamage, we found that cell-impermeant dyes entered damaged cells from luminal or tissue compartments, suggesting a possible slow transcellular, but not paracellular, route for increased permeability after damage. Regarding cytosolic acid/base status, we found that damaged cells acidified (6.63 +/- 0.03) after photodamage, compared with healthy surface cells both near (7.12 +/- 0.06) and far (7.07 +/- 0.04) from damage (P < 0.05). This damaged cell acidification was further attenuated with 20 muM intravenous EIPA (6.34 +/- 0.05, P < 0.05) but unchanged by addition of 0.5 mM luminal H(2)DIDS (6.64 +/- 0.08, P > 0.05). Raising luminal pH did not realkalinize damaged cells, suggesting that the mechanism of acidification is not attributable to leakiness to luminal protons. Inhibition of apical HCO(3)(-) secretion with 0.5 mM luminal H(2)DIDS or genetic deletion of the solute-like carrier 26A9 (SLC26A9) Cl(-)/HCO(3)(-) exchanger blocked the pH(o) increase normally observed in control animals but did not compromise repair of damaged tissue. Addition of exogenous PGE(2) significantly increased pH(o) in wild-type, but not SLC26A9 knockout, animals, suggesting that prostaglandin-stimulated HCO(3)(-) secretion is fully mediated by SLC26A9. We conclude that cellular HCO(3)(-) secretion, likely through SLC26A9, is the dominant mechanism whereby surface pH transiently increases in response to photodamage.
Authors:
Elise S Demitrack; Manoocher Soleimani; Marshall H Montrose
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2010-04-22
Journal Detail:
Title:  American journal of physiology. Gastrointestinal and liver physiology     Volume:  299     ISSN:  1522-1547     ISO Abbreviation:  Am. J. Physiol. Gastrointest. Liver Physiol.     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-06-16     Completed Date:  2010-07-12     Revised Date:  2013-05-29    
Medline Journal Info:
Nlm Unique ID:  100901227     Medline TA:  Am J Physiol Gastrointest Liver Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  G255-64     Citation Subset:  IM    
Affiliation:
Department of Molecular & Cellular Physiology, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Antiporters / deficiency,  genetics,  metabolism*
Bicarbonates / metabolism*
Biological Transport
Chlorides / metabolism*
Cyclic AMP / analogs & derivatives,  metabolism
Dextrans / metabolism
Dinoprostone / metabolism
Fluoresceins / metabolism
Gastric Acid / metabolism*
Gastric Acidity Determination
Gastric Mucosa / drug effects,  metabolism*,  pathology,  radiation effects
Hydrogen-Ion Concentration
Mice
Mice, Inbred C57BL
Mice, Knockout
Microscopy, Confocal
Microscopy, Fluorescence, Multiphoton
NADP / metabolism
Permeability
Time Factors
Grant Support
ID/Acronym/Agency:
DK 62809/DK/NIDDK NIH HHS; R01 DK 54940/DK/NIDDK NIH HHS; R01 DK054940-10/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/Antiporters; 0/Bicarbonates; 0/Chlorides; 0/Fluoresceins; 0/Slc26a9 protein, mouse; 0/fluorescein-dextran; 363-24-6/Dinoprostone; 39824-30-1/8-aminohexylamino cAMP; 53-59-8/NADP; 60-92-4/Cyclic AMP; 9004-54-0/Dextrans
Comments/Corrections

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