BU-E-75 is a guanidine-type H2 receptor agonist that exhibits antagonism at postsynaptic α-adrenoceptors, which can relax the noradrenaline-precontracted vessels[1].
References
[1] Bungardt E, et al. Histamine H1 receptors mediate vasodilation in guinea-pig ileum resistance vessels: characterization with computer-assisted videomicroscopy and new selective agonists. Eur J Pharmacol. 1992 Oct 6;221(1):91-8. DOI:10.1016/0014-2999(92)90776-z
