Data/hora: 01/06/2024 02:14:14

Provedor de dados: 	56	
País: 	Brazil	
Título: 	A key role for Na+/K+-ATPase in the endothelium-dependent oscillatory activity of mouse small mesenteric arteries	
Autores: 	Giachini,F.R.C.; Carneiro,F.S.; Lima,V.V.; Carneiro,Z.N.; Brands,M.W.; Webb,R.C.; Tostes,R.C.	
Data: 	2009-11-01	
Ano: 	2009	
Palavras-chave: 	Oscillatory activity; Na+/K+-ATPase pump; Ouabain; Small mesenteric arteries.	
Resumo: 	Oscillatory contractile activity is an inherent property of blood vessels. Various cellular mechanisms have been proposed to contribute to oscillatory activity. Mouse small mesenteric arteries display a unique low frequency contractile oscillatory activity (1 cycle every 10-12 min) upon phenylephrine stimulation. Our objective was to identify mechanisms involved in this peculiar oscillatory activity. First-order mesenteric arteries were mounted in tissue baths for isometric force measurement. The oscillatory activity was observed only in vessels with endothelium, but it was not blocked by L-NAME (100 µM) or indomethacin (10 µM), ruling out the participation of nitric oxide and prostacyclin, respectively, in this phenomenon. Oscillatory activity was not observed in vessels contracted with K+ (90 mM) or after stimulation with phenylephrine plus 10 mM K+. Ouabain (1 to 10 µM, an Na+/K+-ATPase inhibitor), but not K+ channel antagonists [tetraethylammonium (100 µM, a nonselective K+ channel blocker), Tram-34 (10 µM, blocker of intermediate conductance K+ channels) or UCL-1684 (0.1 µM, a small conductance K+ channel blocker)], inhibited the oscillatory activity. The contractile activity was also abolished when experiments were performed at 20°C or in K+-free medium. Taken together, these results demonstrate that Na+/K+-ATPase is a potential source of these oscillations. The presence of α-1 and α-2 Na+/K+-ATPase isoforms was confirmed in murine mesenteric arteries by Western blot. Chronic infusion of mice with ouabain did not abolish oscillatory contraction, but up-regulated vascular Na+/K+-ATPase expression and increased blood pressure. Together, these observations suggest that the Na+/K+ pump plays a major role in the oscillatory activity of murine small mesenteric arteries.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001100010	
Editor: 	Associação Brasileira de Divulgação Científica	
Relação: 	10.1590/S0100-879X2009005000033	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Medical and Biological Research  v.42 n.11 2009	
Fonte: 	info:eu-repo/semantics/openAccess