Sympathetic activation in rats with L-NAME-induced hypertension
Braz. j. med. biol. res
;
40(3): 401-408, Mar. 2007.
Artigo
em Inglês
| LILACS
| ID: lil-441762
ABSTRACT
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.
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Sistema Nervoso Simpático
/
Resistência Vascular
/
Débito Cardíaco
/
Óxido Nítrico Sintase
/
Hipertensão
Limite:
Animais
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
2007
Tipo de documento:
Artigo
País de afiliação:
Brasil
Instituição/País de afiliação:
Universidade Federal de São Paulo/BR
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