Please use this identifier to cite or link to this item: https://repositorio.unifesp.br/handle/11600/684
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dc.contributor.authorVassallo, Paula Frizela
dc.contributor.authorStefanon, Ivanita
dc.contributor.authorRossoni, Luciana Venturini
dc.contributor.authorTucci, Paulo José Ferreira [UNIFESP]
dc.contributor.authorVassallo, Dalton Valentim
dc.date.accessioned2015-06-14T13:24:47Z
dc.date.available2015-06-14T13:24:47Z
dc.date.issued1998-10-01
dc.identifierhttp://dx.doi.org/10.1590/S0100-879X1998001000019
dc.identifier.citationBrazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 31, n. 10, p. 1353-1359, 1998.
dc.identifier.issn0100-879X
dc.identifier.urihttp://repositorio.unifesp.br/handle/11600/684
dc.description.abstractMyocardial contractility depends on several mechanisms such as coronary perfusion pressure (CPP) and flow as well as on a1-adrenoceptor stimulation. Both effects occur during the sympathetic stimulation mediated by norepinephrine. Norepinephrine increases force development in the heart and produces vasoconstriction increasing arterial pressure and, in turn, CPP. The contribution of each of these factors to the increase in myocardial performance needs to be clarified. Thus, in the present study we used two protocols: in the first we measured mean arterial pressure, left ventricular pressure and rate of rise of left ventricular pressure development in anesthetized rats (N = 10) submitted to phenylephrine (PE) stimulation before and after propranolol plus atropine treatment. These observations showed that in vivo a1-adrenergic stimulation increases left ventricular-developed pressure (P<0.05) together with arterial blood pressure (P<0.05). In the second protocol, we measured left ventricular isovolumic systolic pressure (ISP) and CPP in Langendorff constant flow-perfused hearts. The hearts (N = 7) were perfused with increasing flow rates under control conditions and PE or PE + nitroprusside (NP). Both CPP and ISP increased (P<0.01) as a function of flow. CPP changes were not affected by drug treatment but ISP increased (P<0.01). The largest ISP increase was obtained with PE + NP treatment (P<0.01). The results suggest that both mechanisms, i.e., direct stimulation of myocardial a1-adrenoceptors and increased flow, increased cardiac performance acting simultaneously and synergistically.en
dc.format.extent1353-1359
dc.language.isoeng
dc.publisherAssociação Brasileira de Divulgação Científica
dc.relation.ispartofBrazilian Journal of Medical and Biological Research
dc.rightsAcesso aberto
dc.subjectmyocardial performanceen
dc.subjectcoronary perfusion pressureen
dc.subjectcoronary flowen
dc.subjectphenylephrineen
dc.titleThe left ventricular contractility of the rat heart is modulated by changes in flow and a1-adrenoceptor stimulationen
dc.typeArtigo
dc.contributor.institutionUniversidade Federal do Espírito Santo
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.description.affiliationUniversidade Federal do Espírito Santo
dc.description.affiliationUniversidade Federal de São Paulo (UNIFESP)
dc.description.affiliationUnifespUNIFESP
dc.identifier.fileS0100-879X1998001000019.pdf
dc.identifier.scieloS0100-879X1998001000019
dc.identifier.doi10.1590/S0100-879X1998001000019
dc.description.sourceSciELO
dc.identifier.wosWOS:000076614900019
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