| Registro completo |
| Provedor de dados: |
56
|
| País: |
Brazil
|
| Título: |
Baroreflex function in conscious rats submitted to iron overload
|
| Autores: |
Cardoso,L.M.
Pedrosa,M.L.
Silva,M.E.
Moraes,M.F.D.
Colombari,E.
Chianca-Jr.,D.A.
|
| Data: |
2005-02-01
|
| Ano: |
2005
|
| Palavras-chave: |
Baroreflex
Iron overload
Heart rate
Blood pressure
Iron dextran
Deferoxamine
|
| Resumo: |
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.
|
| Tipo: |
Info:eu-repo/semantics/article
|
| Idioma: |
Inglês
|
| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000200008
|
| Editor: |
Associação Brasileira de Divulgação Científica
|
| Relação: |
10.1590/S0100-879X2005000200008
|
| Formato: |
text/html
|
| Fonte: |
Brazilian Journal of Medical and Biological Research v.38 n.2 2005
|
| Direitos: |
info:eu-repo/semantics/openAccess
|
|
