Sympathetic activation in rats with L-NAME-induced hypertension

Sympathetic activation in rats with L-NAME-induced hypertension

Autor Biancardi, Vinicia Campana Autor UNIFESP Google Scholar
Bergamaschi, Cassia Toledo Autor UNIFESP Google Scholar
Lopes, Oswaldo Ubriaco Autor UNIFESP Google Scholar
Campos, Ruy Ribeiro Autor UNIFESP Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
Resumo We evaluated the hemodynamic pattern and the contribution of the sympathetic nervous system in conscious and anesthetized (1.4 g/kg urethane, iv) Wistar rats with L-NAME-induced hypertension (20 mg/kg daily). The basal hemodynamic profile was similar for hypertensive animals, conscious (N = 12) or anesthetized (N = 12) treated with L-NAME for 2 or 7 days: increase of total peripheral resistance associated with a decrease of cardiac output (CO) compared to normotensive animals, conscious (N = 14) or anesthetized (N = 14). Sympathetic blockade with hexamethonium essentially caused a decrease in total peripheral resistance in hypertensive animals (conscious, 2 days: from (means ± SEM) 2.47 ± 0.08 to 2.14 ± 0.07; conscious, 7 days: from 2.85 ± 0.13 to 2.07 ± 0.33; anesthetized, 2 days: from 3.00 ± 0.09 to 1.83 ± 0.25 and anesthetized, 7 days: from 3.56 ± 0.11 to 1.53 ± 0.10 mmHg mL-1 min-1) with no change in CO in either group. However, in the normotensive group a fall in CO (conscious: from 125 ± 4.5 to 96 ± 4; anesthetized: from 118 ± 1.5 to 104 ± 5.5 mL/min) was observed. The responses after hexamethonium were more prominent in the hypertensive anesthetized group. However, no difference was observed between conscious and anesthetized normotensive rats in response to sympathetic blockade. The present study shows that the vasoconstriction in response to L-NAME was mediated by the sympathetic drive. The sympathetic tone plays an important role in the initiation and maintenance of hypertension.
Palavra-chave L-NAME hypertension
Sympathetic nervous system
Nitric oxide synthase blockade
Total peripheral resistance
Idioma Inglês
Data de publicação 2007-03-01
Publicado em Brazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 40, n. 3, p. 401-408, 2007.
ISSN 0100-879X (Sherpa/Romeo, fator de impacto)
Publicador Associação Brasileira de Divulgação Científica
Extensão 401-408
Fonte http://dx.doi.org/10.1590/S0100-879X2006005000077
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000244667700016
SciELO S0100-879X2007000300016 (estatísticas na SciELO)
Endereço permanente http://repositorio.unifesp.br/handle/11600/3571

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