Evidence for kappa- and mu-opioid receptor expression in C6 glioma cells.
The astrocytoma cell line rat C6 glioma has been used as a model system to study the mechanism of various opioid actions. Nevertheless, the type of opioid receptor(s) involved has not been established. Here we demonstrate the presence of high-affinity U69,593, endomorphin-1, morphine, and beta-endorphin binding in desipramine (DMI)-treated C6 cell membranes by performing homologous and heterologous binding assays with [3H]U69,593, [3H]morphine, or 125I-beta-endorphin. Naive C6 cell membranes displayed U69,593 but neither endomorphin-1, morphine, nor beta-endorphin binding. Cross-linking of 125I-beta-endorphin to C6 membranes gave labeled bands characteristic of opioid receptors. Moreover, RT-PCR analysis of opioid receptor expression in control and DMI-treated C6 cells indicate that both kappa- and mu-opioid receptors are expressed. There does not appear to be a significant difference in the level of mu nor kappa receptor expression in naive versus C6 cells treated with DMI over a 20-h period. Collectively, the data indicate that kappa- and mu-opioid receptors are present in C6 glioma cells.
Bohn
L M
LM
E. A. Doisy Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, Missouri 63104, USA.
Belcheva
M M
MM
Coscia
C J
CJ
D000700:Analgesics / Q000378:metabolism; D000701:Analgesics, Opioid / Q000378:metabolism; D000818:Animals; D044482:Benzeneacetamides; D001667:Binding, Competitive; D003891:Desipramine / Q000494:pharmacology; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D009020:Morphine / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011759:Pyrrolidines / Q000378:metabolism; D051381:Rats; D017473:Receptors, Opioid, kappa / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000378:metabolism*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D001615:beta-Endorphin / Q000378:metabolism
D000700:Analgesics; D000701:Analgesics, Opioid; D044482:Benzeneacetamides; D011759:Pyrrolidines; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D001615:beta-Endorphin; D009020:Morphine; C045444:U 69593; D003891:Desipramine