Opioid, σ, and phencyclidine (PCP) receptors were characterized in the mouse neuroblastoma - Chinese hamster brain hybrid cell line NCB-20. Quantitative receptor assays under equilibrium binding conditions with highly specific radioligands demonstrated the presence of δ, but not μ or κ, opioid receptors on NCB-20 cell membranes. NCB-20 cells were shown to possess two distinct sites specific for σ opioids and PCP derivatives. One site was labeled by (+)-[3H]N-allylnormetazocine [(+)-[3H]SKF-10,047] (K(d) = 69 nM; B(max) = 4100 fmol/mg of protein). The rank order of potency of drugs at this site was (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [(+)-3-PPP] > haloperidol > (+)-SKF-10,047 > (±)-ethylketocyclazocine > (±)-bremazocine > N-[1-(2-thienyl)cyclohexyl]piperidine (TCP) > dexoxadrol. This site is similar in its ligand selectivity to the haloperidol-sensitive σ receptor of rat brain. The other site was labeled by the potent phencyclidine derivative [3H]TCP (K(d) = 335 nM; B(max) = 9300 fmol/mg of protein). This density is equivalent to approximately 60,000 sites/cell. The rank order of potency of drugs at this site was TCP > (+)-3-PPP > PCP > dexoxadrol > haloperidol > cyclazocine > levoxadrol > (+)-SKF-10,047; μ and δ ligands were inactive. This site is similar to the rat brain PCP receptor. The NCB-20 cell line is the only cultured cell line that has been demonstrated to have PCP receptors.
|Original language||English (US)|
|Number of pages||6|
|State||Published - 1988|
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