Effects of a new PAR1 antagonist, F 16618, on smooth muscle cell contraction

This study evaluated the effects of two PAR1 antagonists on vessels contracted by SFLLR. ER 121958 antagonized the SFLLR-induced contraction on rat denuded superior mesenteric artery and pig coronary artery in a non-competitive manner (IC50 values were 22 [7.5–43.6] nM and 2.9 [2.09–4.02] nM, respectively). F 16618 inhibited the SFLLR-induced superior mesenteric arteries and coronary arteries contraction in a competitive manner (pA2 values of 7.3 and 6.2, respectively). PAR1 antagonists do not affect vessel resting tension or haemodynamic parameters in anaesthetized rats. Thus, PAR1 antagonists could have beneficial effects against vasospasm due to vessel injury.