Dermorphin is an opioid peptide originally isolated from the skin of South American frogs (Ph. sauvagei).1 It binds to μ-opioid receptors (Ki = 0.54 nM) and is selective for μ- over δ-opioid receptors in radioligand binding assays (Ki = 929 nM). In vivo, dermorphin (1.9 µmol/kg, i.p.) inhibits noxious stimuli-induced neuronal firing in the nucleus lateralis anterior and ventrobasal complex in rats.2 It inhibits the electrical stimulation-induced C fiber response in rat dorsal horn nociceptive neurons. Dermorphin (10-120 pmol/animal, i.c.v.) delays gastric emptying, inhibits gastric acid secretion, and slows colonic motility in pylorus-ligated rats.
1.Usenko, A.B., Emel'yanova, T.G., and MIasoedov, N.F.Dermorphins are natural opioids with an unique primary structure that determines their biological specificityBiol. Bull. Russ. Acad. Sci.29154-164(2002) 2.Melchiorri, P., and Negri, L.The dermorphin peptide familyGen. Pharmacol.27(7)1099-1107(1996)