Neuropeptide AF (cattle), an amidated octadecapeptide and RFamide neuropeptide, serves as a ligand for Mas-related gene receptor A4 (MrgprA4) (Mas-related G-protein-coupled Receptor (MRGPR)) with an EC50 of approximately 60 nM, and MrgprC11 with an EC50 of around 300 nM. It also activates G protein-coupled receptors NPFF1 (Neuropeptide Y Receptor) with an EC50 ranging from ~25 to 325 nM, and NPFF2 with an EC50 of approximately 1 to 5 nM. Furthermore, Neuropeptide AF (cattle) exhibits anti-opiate effects and modulates related pain [1] [2].