Constriction to ETB receptor agonists, BQ-3020 and sarafotoxin S6c, in human resistance and capacitance vessels in vivo

Aims The aim of the study was to examine the effects of the ETB receptor se lective agonists sarafotoxin S6c (SFTX6c) and BQ-3020 on the forearm resist ance and capacitance vessels in healthy subjects in vivo. Methods The local response to intra-arterial or intravenous infusion of SFT X6c (5 pmol min(-1)) or BQ-3020 (50 pmol min(-1)) was assessed, on separate occasions, in eight healthy men (aged 20-28 years). Data (mean +/- s.e.mea n) were examined by anova. Results are expressed as percentage change from baseline at 90 min. Results SFTX6c and BQ-3020 reduced forearm blood flow, following local intr a-arterial infusion (-25 +/- 7% and -27 +/- 7%, respectively; P < 0.001) an d reduced hand vein diameter, following local intravenous infusion (-30 +/- 8% and -16 +/- 7%, respectively; P < 0.001). Conclusions We have shown that locally active infusions of the selective ET B receptor agonists SFTX6c and BQ-3020 cause arterial constriction and veno constriction in healthy human blood vessels in vivo. These results indicate that ETB receptor stimulation may mediate vasoconstriction in humans.