Baroreflex function in conscious rats submitted to iron overload.

Detalhes bibliográficos
Autor(a) principal: Cardoso, Leonardo Máximo
Data de Publicação: 2005
Outros Autores: Pedrosa, Maria Lúcia, Silva, Marcelo Eustáquio, Moraes, Márcio Flávio Dutra, Colombari, Eduardo, Chianca Júnior, Deoclécio Alves
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da UFOP
Texto Completo: http://www.repositorio.ufop.br/handle/123456789/1813
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.
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spelling Baroreflex function in conscious rats submitted to iron overload.Blood pressureDeferoxamineIron dextranBaroreflexIron overloadHeart rateOur 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.2012-11-26T13:29:38Z2012-11-26T13:29:38Z2005info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfCARDOSO, 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: <http://www.scielo.br/pdf/bjmbr/v38n2/5462.pdf>. Acesso em: 26 nov. 2012.1414431Xhttp://www.repositorio.ufop.br/handle/123456789/1813Todo 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 <http://www.scielo.br/scielo.php?script=sci_serial&pid=0100-879X&lng=en&nrm=iso>. Acesso em: 20 out. 2016.info:eu-repo/semantics/openAccessCardoso, Leonardo MáximoPedrosa, Maria LúciaSilva, Marcelo EustáquioMoraes, Márcio Flávio DutraColombari, EduardoChianca Júnior, Deoclécio Alvesengreponame:Repositório Institucional da UFOPinstname:Universidade Federal de Ouro Preto (UFOP)instacron:UFOP2019-03-13T17:09:34Zoai:repositorio.ufop.br:123456789/1813Repositório InstitucionalPUBhttp://www.repositorio.ufop.br/oai/requestrepositorio@ufop.edu.bropendoar:32332019-03-13T17:09:34Repositório Institucional da UFOP - Universidade Federal de Ouro Preto (UFOP)false
dc.title.none.fl_str_mv Baroreflex function in conscious rats submitted to iron overload.
title Baroreflex function in conscious rats submitted to iron overload.
spellingShingle Baroreflex function in conscious rats submitted to iron overload.
Cardoso, Leonardo Máximo
Blood pressure
Deferoxamine
Iron dextran
Baroreflex
Iron overload
Heart rate
title_short Baroreflex function in conscious rats submitted to iron overload.
title_full Baroreflex function in conscious rats submitted to iron overload.
title_fullStr Baroreflex function in conscious rats submitted to iron overload.
title_full_unstemmed Baroreflex function in conscious rats submitted to iron overload.
title_sort Baroreflex function in conscious rats submitted to iron overload.
author Cardoso, Leonardo Máximo
author_facet Cardoso, Leonardo Máximo
Pedrosa, Maria Lúcia
Silva, Marcelo Eustáquio
Moraes, Márcio Flávio Dutra
Colombari, Eduardo
Chianca Júnior, Deoclécio Alves
author_role author
author2 Pedrosa, Maria Lúcia
Silva, Marcelo Eustáquio
Moraes, Márcio Flávio Dutra
Colombari, Eduardo
Chianca Júnior, Deoclécio Alves
author2_role author
author
author
author
author
dc.contributor.author.fl_str_mv Cardoso, Leonardo Máximo
Pedrosa, Maria Lúcia
Silva, Marcelo Eustáquio
Moraes, Márcio Flávio Dutra
Colombari, Eduardo
Chianca Júnior, Deoclécio Alves
dc.subject.por.fl_str_mv Blood pressure
Deferoxamine
Iron dextran
Baroreflex
Iron overload
Heart rate
topic Blood pressure
Deferoxamine
Iron dextran
Baroreflex
Iron overload
Heart rate
description 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.
publishDate 2005
dc.date.none.fl_str_mv 2005
2012-11-26T13:29:38Z
2012-11-26T13:29:38Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv 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: <http://www.scielo.br/pdf/bjmbr/v38n2/5462.pdf>. Acesso em: 26 nov. 2012.
1414431X
http://www.repositorio.ufop.br/handle/123456789/1813
identifier_str_mv 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: <http://www.scielo.br/pdf/bjmbr/v38n2/5462.pdf>. Acesso em: 26 nov. 2012.
1414431X
url http://www.repositorio.ufop.br/handle/123456789/1813
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv reponame:Repositório Institucional da UFOP
instname:Universidade Federal de Ouro Preto (UFOP)
instacron:UFOP
instname_str Universidade Federal de Ouro Preto (UFOP)
instacron_str UFOP
institution UFOP
reponame_str Repositório Institucional da UFOP
collection Repositório Institucional da UFOP
repository.name.fl_str_mv Repositório Institucional da UFOP - Universidade Federal de Ouro Preto (UFOP)
repository.mail.fl_str_mv repositorio@ufop.edu.br
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