Can a specific peptide help regulate blood pressure in the kidneys? This study explores the role of angiotensin-(1-7) (Ang-[1-7]) in regulating the reactivity of afferent arterioles, small blood vessels in the kidneys. The central hypothesis is that Ang-(1-7), acting on specific receptors, contributes to the control of afferent arteriole tone. The researchers examined the direct effect of Ang-(1-7) on isolated rabbit afferent arterioles microperfused in vitro. Increasing concentrations of Ang-(1-7) produced dose-dependent vasodilatation, increasing luminal diameter. Indomethacin had no effect on Ang-(1-7)–induced dilatation, while N(G)-nitro-L-arginine methyl ester (L-NAME), a NO synthesis inhibitor, abolished it. The Ang-(1-7) antagonist, [d-Ala(7)]–Ang-(1-7), also abolished the dilatation induced by Ang-(1-7), while angiotensin II type 1 and type 2 receptor antagonists had no effect. The results show that Ang-(1-7) causes afferent arteriole dilatation, possibly due to NO production. This effect is mediated by Ang-(1-7) receptors, as angiotensin type 1 and type 2 receptor antagonists could not block Ang-(1-7)–induced dilatation. The data suggest that Ang-(1-7) opposes the action of Ang II and plays a key role in renal hemodynamics regulation.
Published in Hypertension, this study falls within the journal's scope by investigating the mechanisms that control blood pressure and vascular function. The focus on angiotensin-(1-7) and its effects on renal arterioles directly relates to the journal's interest in understanding the regulation of blood pressure and the pathogenesis of hypertension. The paper's findings offer insights into potential therapeutic targets for managing blood pressure and renal function.