Regional intestinal adaptations in Na+,K+-ATPase in experimental colitis and the contrasting effects of interferon-gamma

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Magro F (Author) FMUP; Sonia Fraga (Author) Other; Ribeiro, T (Author) Other; soares-da-silva, p (Author) FMUP

Journal

Title: Acta Physiologica Scandinavica

Vol. 183

Pages: 191-199

ISSN: 0001-6772

Publisher: Blackwell

Indexing

ISI Web of Knowledge - 11 Citations

Scopus - 10 Citations

Other information

Authenticus ID: P-000-4RS

DOI: 10.1111/j.1365-201x.2004.01388.x

Abstract (EN): Aims: This study evaluated Na+,K+-ATPase activity and the abundance of alpha(1) 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 muL). 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 alpha(1) 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 alpha(1) 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9