[(125)I]orphanin FQ/nociceptin binding in Raji cells.
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.
Hom
J S
JS
The Laboratory of Hematopoietic Cancer Immunochemistry and The Cotzias Laboratory of Neuro-Oncology, The Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Goldberg
I
I
Mathis
J
J
Pan
Y X
YX
Brooks
A I
AI
Ryan-Moro
J
J
Scheinberg
D A
DA
Pasternak
G W
GW
D000911:Antibodies, Monoclonal; D001665:Binding Sites; D015153:Blotting, Western; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007457:Iodine Radioisotopes; D016393:Lymphoma, B-Cell / Q000378:metabolism*; D018847:Opioid Peptides / Q000494:pharmacology*; D011869:Radioligand Assay; D011957:Receptors, Opioid / Q000378:metabolism*; D013997:Time Factors; D014407:Tumor Cells, Cultured; D000094942:Nociceptin Receptor; D000097629:Nociceptin
D000911:Antibodies, Monoclonal; D007457:Iodine Radioisotopes; D018847:Opioid Peptides; D011957:Receptors, Opioid; D000094942:Nociceptin Receptor; D000097629:Nociceptin; C000722283:OPRL1 protein, human