Sympathetic inhibition and attenuation of spontaneous hypertension by PVN lesions in rats.
Brain Res
; 543(2): 296-300, 1991 Mar 15.
Article
em En
| MEDLINE
| ID: mdl-1676330
ABSTRACT
To determine whether the paraventricular nucleus (PVN) contributes to the development of hypertension in spontaneously hypertensive rats (SHR), we compared cardiovascular responses to ganglionic blockade with hexamethonium or vasopressin antagonism with dPVAVP in sham-operated or PVN lesioned SHR and Wistar-Kyoto rats (WKY). Lesions were produced electrolytically when the rats were 5 weeks old. During the next 3 weeks, tail-cuff measurements showed that the development of hypertension in SHR was inhibited, while systolic pressure in WKY was unaffected. Mean pressures recorded directly from the femoral artery at 8 weeks of age were lower in lesioned than in sham-operated SHR (141 +/- 5 vs 110 +/- 3 mm Hg, P less than 0.05), but did not differ in corresponding WKY groups (110 +/- 4 vs 112 +/- 5 mm Hg). Depressor responses to ganglionic blockade induced by i.v. injection of hexamethonium (25 mg/kg) were significantly larger in sham-operated than in lesioned SHR (-41 +/- 4% vs -28 +/- 3%, P less than 0.05). By contrast, vasopressin antagonism with dPVAVP did not alter blood pressure in all rat groups. In 24-h urine samples, excretion of vasopressin was unaffected, but that of norepinephrine was significantly reduced in lesioned SHR. These findings suggest that the PVN contributes to the development of spontaneous hypertension by sympathetic activation without increasing vasopressin secretion.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Núcleo Hipotalâmico Paraventricular
/
Sistema Nervoso Simpático
/
Hipertensão
Limite:
Animals
Idioma:
En
Revista:
Brain Res
Ano de publicação:
1991
Tipo de documento:
Article
País de afiliação:
Japão