Presence and characterization of nociceptin (orphanin FQ) receptor binding in adult rat and human fetal hypothalamus

• Published in: Brain research Vol. 762; no. 1; pp. 247 - 250
• Main Authors: Makman, Maynard H, Lyman, William D, Dvorkin, B
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 11.07.1997
• Subjects: Animals; Binding, Competitive - physiology; Dynorphin A; Female; Fetus - chemistry; GTP-Binding Proteins - metabolism; Humans; Hypothalamus; Hypothalamus - chemistry; Hypothalamus - embryology; Iodine Radioisotopes; Male; Nociceptin; Opioid; Orphanin FQ; Radioligand Assay; Rats; Rats, Sprague-Dawley; Receptor; Receptors, Opioid - analysis; Receptors, Opioid - metabolism; Nociceptin; Orphanin FQ; nH, Hill coefficient (slope); Receptor; Opioid; Dynorphin A; Gpp(NH)p, 5′-guanylimidodiphosphate; Hypothalamus; GTP, guanosine triphosphate
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/S0006-8993(97)00503-9

High affinity and saturable nociceptin (orphanin FQ) receptors were detected and characterized in adult rat and human fetal hypothalamic membranes, utilizing [ 125I]Tyr 12-nociceptin as ligand. Nociceptin bound with picomolar affinity, dynorphin A with nanomolar affinity, naloxone and dynorphan A(1–8) with micromolar while des-Tyr 1-dynorphin (dynorphin A(2–17)), several other opioids, morphine and benzomorphans failed to compete for binding at 1–10 μM. Gpp(NH)p together with sodium ion markedly decreased binding, consistent with involvement of a G protein-linked receptor.