Sympathetic activation in rats with L-NAME-induced hypertension
Braz. j. med. biol. res
;
40(3): 401-408, Mar. 2007.
Artículo
en Inglés
| 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:
Disponible
Índice:
LILACS (Américas)
Asunto principal:
Sistema Nervioso Simpático
/
Resistencia Vascular
/
Gasto Cardíaco
/
Óxido Nítrico Sintasa
/
Hipertensión
Límite:
Animales
Idioma:
Inglés
Revista:
Braz. j. med. biol. res
Asunto de la revista:
Biologia
/
Medicina
Año:
2007
Tipo del documento:
Artículo
País de afiliación:
Brasil
Institución/País de afiliación:
Universidade Federal de São Paulo/BR
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