Baroreflex function in conscious rats submitted to iron overload

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dc.contributor.authorCardoso, Leonardo Máximo
dc.contributor.authorPedrosa, Maria Lúcia Silva
dc.contributor.authorSilva, Marcelo Eustáquio
dc.contributor.authorMoraes, Márcio Flávio Dutra
dc.contributor.authorColombari, Eduardo [UNIFESP]
dc.contributor.authorChianca-Junior, Deoclécio Alves
dc.contributor.institutionUniversidade Federal de Ouro Preto NUPEB Departamento de Ciências Biológicas
dc.contributor.institutionUniversidade Federal de Ouro Preto Escola de Nutrição Departamento de Alimentos
dc.contributor.institutionUniversidade Federal de Minas Gerais Instituto de Ciências Biológicas Departamento de Fisiologia e Biofísica
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.date.accessioned2015-06-14T13:31:26Z
dc.date.available2015-06-14T13:31:26Z
dc.date.issued2005-02-01
dc.description.abstractOur hypothesis is that iron accumulated in tissue, rather than in serum, may compromise cardiovascular control. Male Fischer 344 rats weighing 180 to 220 g were divided into 2 groups. In the serum iron overload group (SIO, N = 12), 20 mg elemental iron was injected ip daily for 7 days. In the tissue iron overload group (TIO, N = 19), a smaller amount of elemental iron was injected (10 mg, daily) for 5 days followed by a resting period of 7 days. Reflex heart rate responses were elicited by iv injections of either phenylephrine (0.5 to 5.0 µg/kg) or sodium nitroprusside (1.0 to 10.0 µg/kg). Baroreflex curves were determined and fitted to sigmoidal equations and the baroreflex gain coefficient was evaluated. To evaluate the role of other than a direct effect of iron on tissue, acute treatment with the iron chelator deferoxamine (20 mg/kg, iv) was performed on the TIO group and the baroreflex was re-evaluated. At the end of the experiments, evaluation of iron levels in serum confirmed a pronounced overload for the SIO group (30-fold), in contrast to the TIO group (2-fold). Tissue levels of iron, however, were higher in the TIO group. The SIO protocol did not produce significant alterations in the baroreflex curve response, while the TIO protocol produced a nearly 2-fold increase in baroreflex gain (-4.34 ± 0.74 and -7.93 ± 1.08 bpm/mmHg, respectively). The TIO protocol animals treated with deferoxamine returned to sham levels of baroreflex gain (-3.7 ± 0.3 sham vs -3.6 ± 0.2 bpm/mmHg) 30 min after the injection. Our results indicate an effect of tissue iron overload on the enhancement of baroreflex sensitivity.en
dc.description.affiliationUniversidade Federal de Ouro Preto NUPEB Departamento de Ciências Biológicas
dc.description.affiliationUniversidade Federal de Ouro Preto Escola de Nutrição Departamento de Alimentos
dc.description.affiliationUniversidade Federal de Minas Gerais Instituto de Ciências Biológicas Departamento de Fisiologia e Biofísica
dc.description.affiliationUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Fisiologia
dc.description.affiliationUnifespUNIFESP, EPM, Depto. de Fisiologia
dc.description.sourceSciELO
dc.format.extent205-214
dc.identifierhttp://dx.doi.org/10.1590/S0100-879X2005000200008
dc.identifier.citationBrazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 38, n. 2, p. 205-214, 2005.
dc.identifier.doi10.1590/S0100-879X2005000200008
dc.identifier.fileS0100-879X2005000200008.pdf
dc.identifier.issn0100-879X
dc.identifier.scieloS0100-879X2005000200008
dc.identifier.urihttp://repositorio.unifesp.br/handle/11600/2390
dc.identifier.wosWOS:000227480900008
dc.language.isoeng
dc.publisherAssociação Brasileira de Divulgação Científica
dc.relation.ispartofBrazilian Journal of Medical and Biological Research
dc.rightsinfo:eu-repo/semantics/openAccess
dc.subjectBaroreflexen
dc.subjectIron overloaden
dc.subjectHeart rateen
dc.subjectBlood pressureen
dc.subjectIron dextranen
dc.subjectDeferoxamineen
dc.titleBaroreflex function in conscious rats submitted to iron overloaden
dc.typeinfo:eu-repo/semantics/article
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