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Hypertrophied myocardium is more dependent on extracellular calcium than the normal cardiac muscle.
de Barros, Reginaldo; Zornoff, Leonardo A M; Ribeiro, Henrique B; Okoshi, Marina P; Padovani, Carlos R; Aragon, Flavio F; Cicogna, Antonio C.
Afiliação
  • de Barros R; Botucatu Medical School, UNESP-São Paulo State University, Botucatu, Brazil.
Med Sci Monit ; 16(8): BR278-84, 2010 Aug.
Article em En | MEDLINE | ID: mdl-20671609
BACKGROUND: The aim of this study was to analyze stable hypertrophied myocardial function and its response to inotropic maneuvers in rats submitted to renovascular hypertension for a 10-week period (RHT group, n=10). MATERIAL/METHODS: Myocardial performance was studied in isolated left ventricle papillary muscles in isometric contraction under the following conditions: at postrest contraction of 30 seconds (PRC), at extracellular calcium (ECa2+) chloride concentration of 1.25 and 5.20 mM, and after beta-adrenergic stimulation with 10-6 M isoproterenol (ISOP). RESULTS: The results were compared with normotensive Wistar controls rats (C group, n=10). In basal condition, resting tension, and contraction time (TPT) were greater, while relaxation time (RT50) tended to be longer in RHT than C group. PRC and ISOP promoted a similar change in muscle function response intensity (delta) in both groups. ECa2+ shift did not change TPT in the C group and decreased TPT in the RHT animals; delta was different between these groups. RT50 increased in C and decreased in RHT, both without statistical significance; however, delta was different. CONCLUSIONS: These results suggest that hypertrophied myocardial dysfunction may be attributed to changes in intracellular calcium cycling.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Cálcio / Espaço Extracelular / Miocárdio Limite: Animals Idioma: En Revista: Med Sci Monit Assunto da revista: MEDICINA Ano de publicação: 2010 Tipo de documento: Article País de afiliação: Brasil País de publicação: Estados Unidos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Cálcio / Espaço Extracelular / Miocárdio Limite: Animals Idioma: En Revista: Med Sci Monit Assunto da revista: MEDICINA Ano de publicação: 2010 Tipo de documento: Article País de afiliação: Brasil País de publicação: Estados Unidos