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Title: Baroreflex function in conscious rats submitted to iron overload.
Authors: Cardoso, Leonardo Máximo
Pedrosa, Maria Lúcia
Silva, Marcelo Eustáquio
Moraes, Márcio Flávio Dutra
Colombari, Eduardo
Chianca Júnior, Deoclécio Alves
Keywords: Blood pressure
Iron dextran
Iron overload
Heart rate
Issue Date: 2005
Citation: CARDOSO, L. M. et al. Baroreflex function in conscious rats submitted to iron overload. Brazilian Journal of Medical and Biological Research, v. 38, n. 2, p. 205-214, fev. 2005. Disponível em: <>. Acesso em: 26 nov. 2012.
Abstract: Our 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.
ISSN: 1414431X
metadata.dc.rights.license: Todo o conteúdo do periódico Brazilian Journal of Medical and Biological Research, exceto onde identificado, está licenciado sob uma licença Creative Commons 4.0 que permite copiar, distribuir e transmitir o trabalho em qualquer suporte ou formato desde que sejam citados o autor e o licenciante. Fonte: Brazilian Journal of Medical and Biological Research <>. Acesso em: 20 out. 2016.
Appears in Collections:DECBI - Artigos publicados em periódicos

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