Cardiac sympathetic overactivity and decreased baroreflex sensitivity in L-NAME hypertensive rats.
Am J Physiol Heart Circ Physiol
; 280(2): H844-50, 2001 Feb.
Article
em En
| MEDLINE
| ID: mdl-11158985
The present study evaluated the possible changes in the autonomic control of heart rate in the hypertensive model induced by the inhibition of nitric oxide synthase. Rats were treated with N(G)-nitro-L-arginine methyl ester (L-NAME group) in the drinking water during 7 days, whereas control groups were treated with tap water (control group) or with the N(G)-nitro-D-arginine methyl ester (D-NAME group), an inactive isomer of the L-NAME molecule. The L-NAME group developed hypertension and tachycardia. The sequential blockade of the autonomic influences with propranolol and methylatropine indicated that the intrinsic heart rate did not differ among groups and revealed a sympathetic overactivity in the control of heart rate in the L-NAME group. The spectral density power of heart rate, calculated using fast-Fourier transformation, indicated a reduced variability in the low-frequency band (0.20-0.60 Hz) for the L-NAME group. The baroreflex sensitivity was also attenuated in these animals when compared with the normotensive control or D-NAME group. Overall, these data indicate cardiac sympathetic overactivity associated with a decreased baroreflex sensitivity in L-NAME hypertensive rats.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sistema Nervoso Simpático
/
Barorreflexo
/
Coração
/
Hipertensão
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol Heart Circ Physiol
Assunto da revista:
CARDIOLOGIA
/
FISIOLOGIA
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos