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A key role for Na+/K+-ATPase in the endothelium-dependent oscillatory activity of mouse small mesenteric arteries
Giachini, F. R. C; Carneiro, F. S; Lima, V. V; Carneiro, Z. N; Brands, M. W; Webb, R. C; Tostes, R. C.
  • Giachini, F. R. C; Medical College of Georgia. Department of Physiology. Augusta. US
  • Carneiro, F. S; Medical College of Georgia. Department of Physiology. Augusta. US
  • Lima, V. V; Medical College of Georgia. Department of Physiology. Augusta. US
  • Carneiro, Z. N; Medical College of Georgia. Department of Physiology. Augusta. US
  • Brands, M. W; Medical College of Georgia. Department of Physiology. Augusta. US
  • Webb, R. C; Medical College of Georgia. Department of Physiology. Augusta. US
  • Tostes, R. C; Medical College of Georgia. Department of Physiology. Augusta. US
Braz. j. med. biol. res ; 42(11): 1058-1067, Nov. 2009. ilus
Artigo em Inglês | LILACS | ID: lil-529110
ABSTRACT
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.
Assuntos

Texto completo: DisponíveL Índice: LILACS (Américas) Assunto principal: Resistência Vascular / Endotélio Vascular / ATPase Trocadora de Sódio-Potássio / Hipertensão / Artérias Mesentéricas Limite: Animais Idioma: Inglês Revista: Braz. j. med. biol. res Assunto da revista: Biologia / Medicina Ano de publicação: 2009 Tipo de documento: Artigo / Documento de projeto País de afiliação: Estados Unidos Instituição/País de afiliação: Medical College of Georgia/US

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Texto completo: DisponíveL Índice: LILACS (Américas) Assunto principal: Resistência Vascular / Endotélio Vascular / ATPase Trocadora de Sódio-Potássio / Hipertensão / Artérias Mesentéricas Limite: Animais Idioma: Inglês Revista: Braz. j. med. biol. res Assunto da revista: Biologia / Medicina Ano de publicação: 2009 Tipo de documento: Artigo / Documento de projeto País de afiliação: Estados Unidos Instituição/País de afiliação: Medical College of Georgia/US