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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
5
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pubmed:dateCreated |
2003-10-16
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pubmed:abstractText |
Reduced gastrointestinal HCO3- secretion contributes to malabsorption and obstructive syndromes in cystic fibrosis. The apical HCO3- transport pathways in these organs have not been defined. We therefore assessed the involvement of apical Cl-/HCO3- exchangers and anion conductances in basal and cAMP-stimulated duodenal HCO3- secretion. Muscle-stripped rat and rabbit proximal duodena were mounted in Ussing chambers, and electrical parameters, HCO3- secretion rates, and 36Cl-, 22Na+, and 3H+ mannitol fluxes were assessed. mRNA expression levels were measured by a quantitative PCR technique. Removal of Cl- from or addition of 1 mM DIDS to the luminal perfusate markedly decreased basal HCO3- secretion but did not influence the HCO3- secretory response to 8-bromo-cAMP, which was inhibited by luminal 5-nitro-2-(3-phenylpropylamino)-benzoate. Bidirectional 22Na+ and 36Cl- flux measurements demonstrated an inhibition rather than a stimulation of apical anion exchange during cAMP-stimulated HCO3- secretion. The ratio of Cl- to HCO3- in the anion secretory response was compatible with both Cl- and HCO3- being secreted via the CFTR anion channel. CFTR expression was very high in the duodenal mucosa of both species. We conclude that in rat and rabbit duodena, an apical Cl-/HCO3- exchanger mediates a significant part of basal HCO3- secretion but is not involved in the HCO3- secretory response to cAMP analogs. The inhibitor profile, the strong predominance of Cl- over HCO3- in the anion secretory response, and the high duodenal CFTR expression levels suggest that a major portion of cAMP-stimulated duodenal HCO3- secretion is directly mediated by CFTR.
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/4,4'-Diisothiocyanostilbene-2,2'-Dis...,
http://linkedlifedata.com/resource/pubmed/chemical/5-nitro-2-(3-phenylpropylamino)benzo...,
http://linkedlifedata.com/resource/pubmed/chemical/Anions,
http://linkedlifedata.com/resource/pubmed/chemical/Bicarbonates,
http://linkedlifedata.com/resource/pubmed/chemical/Bumetanide,
http://linkedlifedata.com/resource/pubmed/chemical/Chloride-Bicarbonate Antiporters,
http://linkedlifedata.com/resource/pubmed/chemical/Chlorides,
http://linkedlifedata.com/resource/pubmed/chemical/Cyclic AMP,
http://linkedlifedata.com/resource/pubmed/chemical/Cystic Fibrosis Transmembrane...,
http://linkedlifedata.com/resource/pubmed/chemical/Ion Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Mannitol,
http://linkedlifedata.com/resource/pubmed/chemical/Nitrobenzoates,
http://linkedlifedata.com/resource/pubmed/chemical/RNA, Messenger,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium
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pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0193-1857
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
285
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
G887-97
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:12842823-4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid,
pubmed-meshheading:12842823-Animals,
pubmed-meshheading:12842823-Anions,
pubmed-meshheading:12842823-Bicarbonates,
pubmed-meshheading:12842823-Bumetanide,
pubmed-meshheading:12842823-Cell Membrane,
pubmed-meshheading:12842823-Chloride-Bicarbonate Antiporters,
pubmed-meshheading:12842823-Chlorides,
pubmed-meshheading:12842823-Cyclic AMP,
pubmed-meshheading:12842823-Cystic Fibrosis Transmembrane Conductance Regulator,
pubmed-meshheading:12842823-Duodenum,
pubmed-meshheading:12842823-Electric Conductivity,
pubmed-meshheading:12842823-Female,
pubmed-meshheading:12842823-Ion Channels,
pubmed-meshheading:12842823-Male,
pubmed-meshheading:12842823-Mannitol,
pubmed-meshheading:12842823-Nitrobenzoates,
pubmed-meshheading:12842823-RNA, Messenger,
pubmed-meshheading:12842823-Rabbits,
pubmed-meshheading:12842823-Rats,
pubmed-meshheading:12842823-Rats, Wistar,
pubmed-meshheading:12842823-Sodium
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pubmed:year |
2003
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pubmed:articleTitle |
Independence of apical Cl-/HCO3- exchange and anion conductance in duodenal HCO3- secretion.
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pubmed:affiliation |
Zentrum Innere Medizin, Abteilung IV, der Medizinischen Hochschule Hannover, Carl-Neuberg Str. 1, 30625 Hannover, Germany.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, Non-U.S. Gov't
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