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Ventricular performance and Na+-K+ ATPase activity are reduced early and late after myocardial infarction in rats.
Stefanon, I; Cade, J R; Fernandes, A A; Ribeiro Junior, R F; Targueta, G P; Mill, J G; Vassallo, D V.
Afiliação
  • Stefanon I; Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, Brasil. ivanita@pq.cnpq.br
Braz J Med Biol Res ; 42(10): 902-11, 2009 Oct.
Article em En | MEDLINE | ID: mdl-19787147
Myocardial infarction leads to compensatory ventricular remodeling. Disturbances in myocardial contractility depend on the active transport of Ca2+ and Na+, which are regulated by Na+-K+ ATPase. Inappropriate regulation of Na+-K+ ATPase activity leads to excessive loss of K+ and gain of Na+ by the cell. We determined the participation of Na+-K+ ATPase in ventricular performance early and late after myocardial infarction. Wistar rats (8-10 per group) underwent left coronary artery ligation (infarcted, Inf) or sham-operation (Sham). Ventricular performance was measured at 3 and 30 days after surgery using the Langendorff technique. Left ventricular systolic pressure was obtained under different ventricular diastolic pressures and increased extracellular Ca2+ concentrations (Ca2+e) and after low and high ouabain concentrations. The baseline coronary perfusion pressure increased 3 days after myocardial infarction and normalized by 30 days (Sham 3 = 88 +/- 6; Inf 3 = 130 +/- 9; Inf 30 = 92 +/- 7 mmHg; P < 0.05). The inotropic response to Ca2+e and ouabain was reduced at 3 and 30 days after myocardial infarction (Ca2+ = 1.25 mM; Sham 3 = 70 +/- 3; Inf 3 = 45 +/- 2; Inf 30 = 29 +/- 3 mmHg; P < 0.05), while the Frank-Starling mechanism was preserved. At 3 and 30 days after myocardial infarction, ventricular Na+-K+ ATPase activity and contractility were reduced. This Na+-K+ ATPase hypoactivity may modify the Na+, K+ and Ca2+ transport across the sarcolemma resulting in ventricular dysfunction.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Função Ventricular Esquerda / ATPase Trocadora de Sódio-Potássio / Contração Miocárdica / Infarto do Miocárdio Limite: Animals Idioma: En Revista: Braz J Med Biol Res Ano de publicação: 2009 Tipo de documento: Article País de afiliação: Brasil País de publicação: Brasil
Texto completo
Adicionar na Minha BVS
Imprimir
XML
PubMed Links
Buscar no Google

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Função Ventricular Esquerda / ATPase Trocadora de Sódio-Potássio / Contração Miocárdica / Infarto do Miocárdio Limite: Animals Idioma: En Revista: Braz J Med Biol Res Ano de publicação: 2009 Tipo de documento: Article País de afiliação: Brasil País de publicação: Brasil