BAM 22P is a potent endogenous agonist, derived from the proenkephalin A gene, for the Mas-related G protein-coupled receptor X1 (MRGPRX1), which was originally isolated from bovine adrenal medulla. BAM 22P is a potent opioid agonist with an IC50 of 1.3 nM in guinea pig ileum. BAM 22P can produces opioid- and non-opioid receptor mediated antinociceptive effects in vivo.