Sigma binding in a human neuroblastoma cell line.
Behaviorally, sigma1 agents modulate opioid analgesia. To examine possible mechanisms responsible for these interactions, we have identified a cell line containing both sigma1 and opioid receptors. [3H](+)-pentazocine binding in BE(2)-C human neuroblastoma cells is high affinity (KD 3.4 +/- 0.7 nM) and high density (Bmax 2.98 +/- 0.14 pmol/mg protein). Competition studies reveal a selectivity profile similar to that of sigma1 sites in guinea pig brain. (+)-Pentazocine has no effect upon either basal or forskolin-stimulated cyclase in the BE(2)-C cells, but cAMP accumulation is inhibited by the morphine, DPDPE and naloxone benzoylhydrazone. (+)-Pentazocine at concentrations as high as 10 microM does not affect this opioid effect, implying that sigma1/opioid interactions are not mediated at the level of the cell. This suggest that their behavioral interactions result from interacting neural circuits. Although (+)-pentazocine is without effect in the cyclase system, it does block carbachol-stimulated phosphoinositol turnover (IC50 6.5 +/- 1.14 microM). The specificity of the effect is confirmed by the ability of haloperidol (1 microM) to shift the IC50 value of (+)-pentazocine 2-fold to the right.
Ryan-Moro
J
J
Cotzias Laboratory of Neuro-Oncology Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Chien
C C
CC
Standifer
K M
KM
Pasternak
G W
GW
D000262:Adenylyl Cyclases / Q000378:metabolism; D000700:Analgesics / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000494:pharmacology*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006168:Guinea Pigs; D006220:Haloperidol / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009447:Neuroblastoma; D010423:Pentazocine / Q000378:metabolism* / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000378:metabolism; D011957:Receptors, Opioid / Q000378:metabolism*; D017480:Receptors, sigma / Q000378:metabolism*; D014357:Trypsin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000700:Analgesics; D004745:Enkephalins; D010716:Phosphatidylinositols; D011957:Receptors, Opioid; D017480:Receptors, sigma; C058380:naloxone benzoylhydrazone; D005576:Colforsin; D006165:Guanylyl Imidodiphosphate; D009270:Naloxone; D009020:Morphine; D020881:Enkephalin, D-Penicillamine (2,5)-; D002217:Carbachol; D000242:Cyclic AMP; D014357:Trypsin; D000262:Adenylyl Cyclases; D006220:Haloperidol; D010423:Pentazocine