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

• Tipo: Artigo em Revista Científica Internacional
• Data: 2005

Autores

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

Revista

Título: Acta Physiologica Scandinavica

Vol. 183

Páginas: 191-199

ISSN: 0001-6772

Editora: Blackwell

Indexação

ISI Web of Knowledge - 11 Citações

Scopus - 10 Citações

Outras Informações

ID Authenticus: 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.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 9