BAM-22P (8-22) is an endogenous neuropeptide derived from proenkephalin A and an agonist of MAS-related G protein-coupled receptor family member X1 (MRGPRX1), previously known as sensory neuron-specific G protein-coupled receptor 4 (SNSR4).1 It is involved in prurition and nociception. BAM-22P (8-22) induces calcium mobilization in HEK293S cells expressing human MRGPRX1 or SNSR3 (EC50s = 14 and 28 nM, respectively) and inhibits voltage-induced calcium currents in isolated rat neurons expressing human MRGPRX1 (EC50 = 0.6 µM).2 Intrathecal administration of BAM-22P (8-22) (30 nmol/animal) decreases the tail-flick latency in rats stimulated with the Gαi inhibitor pertussin toxin and increases the tail-flick latency in rats stimulated with the phospholipase C (PLC) inhibitor U-73122, indicating changes in pain sensitivity.3 BAM-22P (8-22) (100 µg/animal) increases scratching behavior in wild-type mice and enhances bile-duct ligation-induced scratching behavior in a mouse model of cholestasis.4
1.Lembo, P.M.C., Grazzini, E., Groblewski, T., et al.Proenkephalin A gene products activate a new family of sensory neuron-specific GPCRsNat. Neurosci.5(3)201-209(2002) 2.Chen, H., and Ikeda, S.R.Modulation of ion channels and synaptic transmission by a human sensory neuron-specific G-protein-coupled receptor, SNSR4/mrgX1, heterologously expressed in cultured rat neuronsJ. Neurosci.24(21)5044-5053(2004) 3.Chen, T., Wang, D., and Hong, Y.Dual modulation effects of Mas-related gene (Mrg) receptors on pain sensitivity in ratsNeurosci. Lett.514(1)82-85(2012) 4.Sanjel, B., Maeng, H.-J., and Shim, W.-S.BAM8-22 and its receptor MRGPRX1 may attribute to cholestatic pruritusSci. Rep.9(1)10888(2019)