OPRL1 is a G-protein coupled opioid receptor that functions as receptor for the endogenous neuropeptide nociceptin. Ligand binding causes a conformation change in OPRL1 that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors. Signaling via G proteins mediates inhibition of adenylate cyclase activity and calcium channel activity. Arrestins modulate OPRL1 signaling via G proteins and mediate the activation of alternative signaling pathways that lead to the activation of MAP kinases. It plays a role in modulating nociception and the perception of pain, as well as in the regulation of locomotor activity by the neuropeptide nociceptin. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804