Document Detail


Regional intestinal adaptations in Na+,K+-ATPase in experimental colitis and the contrasting effects of interferon-gamma.
MedLine Citation:
PMID:  15676060     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
AIMS: This study evaluated Na+,K+-ATPase activity and the abundance of alpha1 subunit Na+,K+-ATPase in experimental colitis and gathered evidence on the effects of interferon-gamma (IFN-gamma) on intestinal Na+,K+-ATPase. METHODS: Colitis was induced by the intrarectal administration of 2,4,6-trinitrobenzene sulphonic acid (TNBS, 30 mg/250 microL). Na+,K+-ATPase activity was determined as the difference between total and ouabain-insensitive ATPase. The abundance of Na+,K+-ATPase was analysed by immunoblotting. RESULTS: Na+,K+-ATPase activity was markedly reduced in the proximal colonic mucosa of TNBS-treated rats, whereas upstream in the terminal ileal mucosa a marked increase in sodium pump activity was observed. At the jejunal level no significant changes in Na+,K+-ATPase activity were observed between TNBS-treated rats and corresponding controls (ethanol-treated rats). No changes were observed in the abundance of alpha1 subunit Na+,K+-ATPase in the proximal colon, terminal ileum and jejunum. The administration of IFN-gamma (50,000 U) 48 h before sacrifice reduced both Na+,K+-ATPase activity and the abundance of alpha1 subunit Na+,K+-ATPase in the proximal colon. Dexamethasone prevented colonic inflammation and decreases in proximal colonic Na+,K+-ATPase activity in TNBS-treated rats, but did not affect the INF-gamma-induced decrease in colonic Na+,K+-ATPase activity. CONCLUSIONS: The increase in ileal Na+,K+-ATPase activity upstream to the lesioned colonic mucosa, where Na+,K+-ATPase activity was markedly reduced, might indicate a compensatory process to counteract the decrease in water and electrolyte absorption at the colonic level. This decrease in colonic Na+,K+-ATPase activity is likely not related to INF-gamma-induced downregulation of Na+,K+-ATPase.
Authors:
F Magro; S Fraga; T Ribeiro; P Soares-da-Silva
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Acta physiologica Scandinavica     Volume:  183     ISSN:  0001-6772     ISO Abbreviation:  Acta Physiol. Scand.     Publication Date:  2005 Feb 
Date Detail:
Created Date:  2005-01-28     Completed Date:  2005-03-24     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370362     Medline TA:  Acta Physiol Scand     Country:  England    
Other Details:
Languages:  eng     Pagination:  191-9     Citation Subset:  IM    
Affiliation:
Institute of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal.
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MeSH Terms
Descriptor/Qualifier:
Animals
Antineoplastic Agents / pharmacology
Caco-2 Cells / drug effects
Colitis / metabolism*
Colon / drug effects,  enzymology
Dexamethasone / pharmacology
Epithelial Cells / enzymology
Humans
Ileum / drug effects,  enzymology
Interferon-gamma / blood,  pharmacology*
Intestinal Mucosa / enzymology
Jejunum / drug effects,  enzymology
Lower Gastrointestinal Tract / drug effects,  enzymology*
Male
Peroxidase / metabolism
Rats
Rats, Wistar
Sodium-Potassium-Exchanging ATPase / metabolism*
Chemical
Reg. No./Substance:
0/Antineoplastic Agents; 50-02-2/Dexamethasone; 82115-62-6/Interferon-gamma; EC 1.11.1.7/Peroxidase; EC 3.6.3.9/Sodium-Potassium-Exchanging ATPase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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