Isoproterenol-induced heart failure in the rat is associated with nitric oxide-dependent functional alterations of cardiac function.
Eur J Heart Fail
; 11(2): 140-6, 2009 Feb.
Article
en En
| MEDLINE
| ID: mdl-19168511
AIMS: The role of nitric oxide (NO) in heart failure (HF) is complex and remains controversial. We tested the hypothesis that the role of NO in isolated atria and cardiomyocytes is altered in isoproterenol-induced HF. METHODS AND RESULTS: Rats received isoproterenol (ISO, 5 mg/kg/day, intraperitoneally) or vehicle for 1 week. Haemodynamic parameters were obtained by left ventricular catheterization. Effects of NOS inhibition on isolated atria and on electrically paced left ventricular myocytes were determined. Additionally, expressions of nitric oxide synthases and their allosteric modulators hsp90, caveolin-1, and caveolin-3 proteins in the left ventricles were measured. ISO increased left ventricular mass by 33% and decreased indices of left ventricular systolic and diastolic function dp/dtmin and dp/dtmax (both P<0.05). Isolated atria from HF rats had a lower spontaneous beating rate (P<0.05). NOS inhibition by L-NAME increased basal frequency and attenuated the positive chronotropic effect of beta-adrenergic stimulation in the HF group (P<0.05). Ventricular myocytes from failing hearts had impaired cell shortening. L-NAME decreased contractility of control, but not failing myocytes. Left ventricular expressions of eNOS, hsp90, iNOS, but not nNOS or caveolins, were increased. CONCLUSION: Despite the increased capacity for NO synthesis in isoproterenol-induced HF, NO does not sustain contractility of failing myocytes. NO may contribute to the decreased basal heart rate and it may accelerate beta-adrenergic stimulation of chronotropy.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Insuficiencia Cardíaca
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Frecuencia Cardíaca
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Isoproterenol
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Contracción Miocárdica
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Óxido Nítrico
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
Idioma:
En
Revista:
Eur J Heart Fail
Asunto de la revista:
CARDIOLOGIA
Año:
2009
Tipo del documento:
Article
Pais de publicación:
Reino Unido