MedChemExpress AC-55541 is a highly selective protease-activated receptor 2 (PAR2) agonist (pEC50=6.7), displays no activity at other PAR subtypes or at over 30 other receptors involved in nociception and inflammation. AC-55541 has pEC50 values of 5.9 and 6.6 in PI hydrolysis assays and Ca2+ mobilization assays and exhibits pronociceptive activity in vivo.