[Lys4] Sarafotoxin S6c, a sarafotoxin analogue, is a potent and partial agonist of endothelin receptor. [Lys4] Sarafotoxin S6c elicits contraction of pig coronary artery, with an EC50 of 1.5 nM[1].
References
[1] Schoeffter P, et al. Differences between endothelin receptors mediating contraction of guinea-pig aorta and pig coronary artery. Eur J Pharmacol. 1993 Nov 9;249(2):199-206. DOI:10.1016/0014-2999(93)90433-i