Ventricular performance and Na+-K+ ATPase activity are reduced early and late after myocardial infarction in rats.
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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Função Ventricular Esquerda
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ATPase Trocadora de Sódio-Potássio
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Contração Miocárdica
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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