[125I]orphanin FQ/nociceptin binding in Raji cells

✍ Scribed by Judith S.H. Hom; Ira Goldberg; John Mathis; Ying-Xian Pan; Andrew I. Brooks; Jennifer Ryan-Moro; David A. Scheinberg; Gavril W. Pasternak

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 141 KB
• Volume: 34
• Category: Article
• ISSN: 0887-4476
• DOI: 10.1002/(sici)1098-2396(19991201)34:3<187::aid-syn3>3.0.co;2-a

✦ Synopsis

Western blots using an antibody which recognizes the orphanin FQ/ nociceptin (OFQ/N) receptor reveals a band at approximately 69 kD in several cell lines, including the Raji human B cell lymphoma cell line. RT-PCR confirms the presence of this receptor in the Raji cells. Binding studies revealed a high affinity [ 125 I][Tyr 14 ]OFQ/N site in the Raji cells. The affinity of [ 125 I][Tyr 14 ]OFQ/N in the Raji cells (K D 68.4 pM) was similar to that in the transfected receptor (K D 36.7 pM). Its selectivity profile also was quite similar. OFQ/N competed binding quite potently (K i 65 pM), as did [Tyr 14 ]OFQ/N (K i 33 pM). Traditional opioids displayed no appreciable affinity for the binding at any concentration examined, with the exception of naloxone benzoylhydrazone, which had only a very modest affinity. The receptors in the Raji cells were functionally active. OFQ/N inhibited forskolin-stimulated cyclase by 72% with an IC 50 value of approximately 1 nM.