Rapid agonist-induced loss of 125I-beta-endorphin opioid receptor sites in NG108-15, but not SK-N-SH neuroblastoma cells.
We have measured mu and delta opioid receptor sites on intact SK-N-SH and NG108-15 neuroblastoma cells, respectively, in culture. Use of 125I-beta-endorphin (beta E) as a tracer, together with beta E(6-31) to block high-affinity non-opioid binding in both cell lines, permitted the measurement of cell surface mu and delta opioid receptor sites. Labeling was at delta sites in NG108-15 cells and predominantly at mu sites in SK-N-SH cells. Pretreatment with the mu and delta agonist, DADLE, caused a rapid loss of cell surface delta receptor sites in NG108-15 cells, but failed to reduce significantly mu receptor density in SK-N-SH cells.
Cone
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RI
School of Pharmacy, University of California, San Francisco 94143.
Lameh
J
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Sadée
W
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D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D020881:Enkephalin, D-Penicillamine (2,5)-; D016308:Enkephalin, Leucine-2-Alanine / Q000494:pharmacology; D004745:Enkephalins / Q000494:pharmacology; D006801:Humans; D051379:Mice; D009447:Neuroblastoma / Q000378:metabolism*; D011957:Receptors, Opioid / Q000187:drug effects* / Q000378:metabolism; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D014407:Tumor Cells, Cultured / Q000378:metabolism; D001615:beta-Endorphin / Q000378:metabolism
D000700:Analgesics; D004745:Enkephalins; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D001615:beta-Endorphin; D016308:Enkephalin, Leucine-2-Alanine; D020881:Enkephalin, D-Penicillamine (2,5)-