Aldosterone attenuated phenylephrine-mediated constriction by 25+/-4% in endothelium-intact rat aortic rings, but enhanced vasoconstriction in endothelium-denuded vessels.
Does aldosterone affect vascular reactivity in rat aortic ring segments and endothelial cells?
Aldosterone exerts rapid, nongenomic effects on vascular reactivity, attenuating constriction in intact endothelium but enhancing it when denuded, which may contribute to cardiovascular disease pathophysiology.
Effect estimate: 25+/-4% reduction
BACKGROUND: There is increasing evidence for rapid nongenomic effects of aldosterone. Therefore, we studied the immediate effects of aldosterone on vascular reactivity in rat aortic ring segments and on endothelial and vascular smooth muscle cellular responses. METHODS AND RESULTS: In endothelium-intact ring segments, aldosterone attenuated phenylephrine-mediated constriction (maximal reduction, 25+/-4% below control phenylephrine-mediated constriction). In contrast, in endothelium-denuded vessels, aldosterone mediated a monophasic dose-dependent enhancement of vasoconstrictor response. In endothelial cells, aldosterone caused a phosphatidylinositol 3-kinase (PI3K)-dependent increase in nitric oxide synthase activity as well as PI3K-dependent activation of extracellular signal-regulated kinase 1/2 and p70 S6 kinase. CONCLUSIONS: Overall, these data support a novel effect of aldosterone on vascular endothelial and smooth muscle cell function. These rapid effects of aldosterone might be important in both the short- and long-term regulation of peripheral vascular resistance. Furthermore, in the setting of endothelial dysfunction, alterations in aldosterone's short-term vascular responses might contribute to its pathophysiological effects in cardiovascular disease.
Liu et al. (Tue,) reported a other. Aldosterone vs. Control was evaluated on Phenylephrine-mediated constriction in endothelium-intact ring segments (25+/-4% reduction). Aldosterone attenuated phenylephrine-mediated constriction by 25+/-4% in endothelium-intact rat aortic rings, but enhanced vasoconstriction in endothelium-denuded vessels.