An endogenous peptide derived from the same precursor as nociceptin, which is able to block nociceptin-induced allodynia and hyperalgesia and may play an opposing role in pain transmission. Shown to reverse nociceptin inhibition of glutamate release from rat brain slices; also modulates 5-HT transmission in the mouse neocortex via mechanisms separate from nociceptin/orphanin FQ. MW (observed): 1927.07.