Abstract
Des-Arg9-bradykinin (des-Arg9-BK) caused endothelium-dependent relaxations in human, isolated coronary arteries which upregulated with in vitro incubation time. Relaxations to des-Arg9-BK were inhibited by the B1 receptor antagonist, des-Arg9-[Leu8]-BK (pKB, 6.14 ± 0.11) but were unaffected by the B2 receptor antagonist, Hoe-140. Therefore, this is the first demonstration that human coronary arteries possess endothelial B1 receptors which mediate endothelium-dependent relaxation and appear to be synthesized de novo during the incubation period.