Abstract
[Tic4]EM1 and [Tic4]EM2, new endomorphins (EMs) analogues, caused relaxation of rat aorta rings precontracted with phenylphrine in a concentration-dependent manner and were 240- to 370-fold more potent than EMs. This effect was inhibited by endothelium removal or by incubation with NO synthase inhibitor L-NNA or opioid receptor antagonist naloxone. The results demonstrate that [Tic4]EMs have NO- and endothelium-dependent vasorelaxant effects which are mediated by the opioid receptor.
Keywords: tic, endomorphins, opioid, vasorelaxant response, rat aorta rings