The protein encoded by this gene is a G protein-coupled receptor whose expression can be induced by phytohemagglutinin. The encoded integral membrane protein is a receptor for the 17 aa neuropeptide nociceptin/orphanin FQ. This gene may be involved in the regulation of numerous brain activities, particularly instinctive and emotional behaviors. A promoter for this gene also functions as a promoter for another gene, regulator of G-protein signalling 19 (RGS19), located on the opposite strand. Three transcript variants encoding the same protein have been found for this gene.