Circulating and tissue catecholamines in rats with chronic neurogenic hypertension

Abstract

Summary:To study the role of peripheral catecholamines in plasma and different tissues in neurogenic hypertension we measured directly blood pressure, maximum rate of left ventricular pressure rise (dp/dtm~) and heart rate through an aortic catheter 5 weeks after total sino-aortic baroreceptor deafferentation in male Sprague-Dawley rats. Blood samples were collected through the same catheter to determine plasma catecholamine concentrations. Blood pressure and dp/dtmax were significantly higher in neurogenic-hypertensive rats when compared with sham operated rats. Plasma noradrenaline concentrations and plasma adrenaline concentrations reached significantly higher levels in neurogenic-hypertensive rats. In the heart noradrenaline content was lower (when calculated per g wet weight) and in the adrenal medulla adrenaline content was higher in neurogenic-hypertensive rats, when compared with sham operated controls. A significant positive correlation was found between dp/ dtmax and plasma noradrenaline concentrations.It is concluded that sino-aortic baroreceptor deafferentation produces a significant chronic hypertension, probably supported by elevated plasma catecholamine concentrations and enhanced synthesis and release of adrenaline from adrenal medulla.

Reflex adrenal medullary secretion during coronary occlusion mediated by cardiac receptors with afferent vagal fibres in the rat

“…The adrenals are probably involved since the effect of SAD on basal catecholamines concentrations is abolished by adrenal demedullation [31] and adrenal adrenaline synthesis and release are enhanced in rats with SAD [7].…”

Mecanismos celulares ativados por agonistas adrenérgicos em aorta de ratos hipertensos renais com disfusão endotelial

“…Trabalhos demonstram maior concentração de NOR em plasma de animais hipertensos DOCA-Sal e também em modelo de hipertensão neurogênica (Dominiak et al, 1986;Bouvier e Champlain, 1986). Com o objetivo de melhor entender a contribuição da estimulação adrenérgica endógena via Sistema Nervoso Simpático-Adrenal para as alterações funcionais de receptores adrenérgicos no modelo 2R-1C, realizamos a dosagem de NOR no plasma e nas adrenais direita (referente ao rim contra-lateral) e esquerda (referente ao rim, cuja artéria aferente foi clipada), de animais 2R e 2R-1C, mesmo esta sendo a catecolamina secretada em menor proporção dela adrenal.…”

“…Com a hiperatividade simpática e consequente estímulo da medula da suprarenal, ocorre aumento dos níveis plasmáticos de NOR e ADR como é observado em modelos neurogênicos de hipertensão e no modelo DOCA-Sal (Dominiak et al, 1986;Bouvier e Champlain, 1986…”