Effects of brain natriuretic peptide on forearm vasculature: comparison with atrial natriuretic peptide

Objective: The aim of the present study was to determine the vasoactive eff ects of brain natriuretic peptide (BNP) as compared to those of atrial natr iuretic peptide (ANP) in normal man. Methods: Ten healthy male subjects (me dian age 21 (20-23) year) were studied twice. In the first study equimolar doses (1, 3, and 10 pmol/dl/min) of both BNP and ANP (in random order and d ouble blind) were infused into the brachial artery of the non-dominant arm with a l-h wash-out period in between. In the second study two BNP (n=5) or ANP (n=5) dose-response curves were performed in order to assess the repea tability of the BNP/ANP infusions. To this end, BNP and ANP were infused in the same equimolar doses as in the first protocol. Forearm blood flow (FBF ) was determined by venous occlusion plethysmography before and during infu sions. Results: BNP increased the FBF ratio (infused/contralateral arm) by 6%, 17%, and 48%, respectively (p<0.05), while ANP increased the FBF ratio by 4%, 58%, and 133% (p<0.001). The slopes of the BNP dose-response curves differed significantly from those of the ANP curves (18.1 versus 43.2; p=0. 022). No differences were observed between the repeated dose-response curve s of either BNP or ANP. Conclusions: The present data demonstrate that BNP induces a dose-dependent vasodilatation in man. On a molar basis, however, this vasodilatation is significantly less than the vasodilatation induced b y ANP. These differences may be related to differences in natriuretic-pepti de-receptor affinity. Furthermore, our data show that the vasoactive effect s of both BNP and ANP are repeatable in time. (C) 1999 Elsevier Science B.V . All rights reserved.