The OPRM1 gene encodes the mu opioid receptor, which is the primary site of action for the most commonly used opioids, including morphine, heroin, fentanyl, and methadone. It is also the primary receptor for endogenous opioid peptides beta-endorphin (see POMC, MIM 176830) and the enkephalins (see PENK, MIM 131330). The OPRM1 receptor is a membrane of the G protein-coupled receptor family (Bond et al., 1998 [PubMed 9689128]). There are at least 3 types of opioid receptors, mu, kappa (OPRK1; MIM 165196), and delta (OPRD1; MIM 165195), each with a distinct pharmacologic profile (Chen et al., 1993 [PubMed 8393525]).
HMOP; KIAA0403; LMOR; M-OR-1; MOP; MOP receptor; MOR; MOR-1; MOR-1C; MOR1; mu 1; Mu opiate receptor; Mu opioid receptor; Mu opioid receptor hMOR-1a; mu opioid receptor splice variant mMOR-1Z; mu opioid receptor splice variant rMOR-1S; mu opioid receptor splice variant rMOR-1Z; Mu-type opioid receptor; MUOR1; Opioid mu receptor; Opioid mu-type receptor; Opioid receptor; Opioid receptor B; opioid receptor, mu 1; OPRM; OPRM1