| Registro completo |
| Provedor de dados: |
56
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| País: |
Brazil
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| Título: |
Angiotensin II type 1 receptor blockade partially attenuates hypoxia-induced pulmonary hypertension in newborn piglets: relationship with the nitrergic system
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| Autores: |
Camelo Jr.,J.S.
Martins,A.R.
Rosa,E.
Ramos,S.G.
Hehre,D.
Bancalari,E.
Suguihara,C.
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| Data: |
2012-02-01
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| Ano: |
2012
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| Palavras-chave: |
Newborn animals
Pulmonary hypertension
Angiotensin II
Angiotensin receptors
Hypoxia
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| Resumo: |
The objective of this study was to observe possible interactions between the renin-angiotensin and nitrergic systems in chronic hypoxia-induced pulmonary hypertension in newborn piglets. Thirteen chronically instrumented newborn piglets (6.3 ± 0.9 days; 2369 ± 491 g) were randomly assigned to receive saline (placebo, P) or the AT1 receptor (AT1-R) blocker L-158,809 (L) during 6 days of hypoxia (FiO2 = 0.12). During hypoxia, pulmonary arterial pressure (Ppa; P < 0.0001), pulmonary vascular resistance (PVR; P < 0.02) and the pulmonary to systemic vascular resistance ratio (PVR/SVR; P < 0.05) were significantly attenuated in the L (N = 7) group compared to the P group (N = 6). Western blot analysis of lung proteins showed a significant decrease of endothelial NOS (eNOS) in both P and L animals, and of AT1-R in P animals during hypoxia compared to normoxic animals (C group, N = 5; P < 0.01 for all groups). AT1-R tended to decrease in L animals. Inducible NOS (iNOS) did not differ among P, L, and C animals and iNOS immunohistochemical staining in macrophages was significantly more intense in L than in P animals (P < 0.01). The vascular endothelium showed moderate or strong eNOS and AT1-R staining. Macrophages and pneumocytes showed moderate or strong iNOS and AT1-R staining, but C animals showed weak iNOS and AT1-R staining. Macrophages of L and P animals showed moderate and weak AT2-R staining, respectively, but the endothelium of all groups only showed weak staining. In conclusion, pulmonary hypertension induced by chronic hypoxia in newborn piglets is partially attenuated by AT1-R blockade. We suggest that AT1-R blockade might act through AT2-R and/or Mas receptors and the nitrergic system in the lungs of hypoxemic newborn piglets.
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012000200012
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| Editor: |
Associação Brasileira de Divulgação Científica
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| Relação: |
10.1590/S0100-879X2012007500014
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| Formato: |
text/html
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| Fonte: |
Brazilian Journal of Medical and Biological Research v.45 n.2 2012
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| Direitos: |
info:eu-repo/semantics/openAccess
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