Sigma receptors on NCB-20 hybrid neurotumor cells labeled with (+)[3H]SKF 10,047 and (+)[3H]3-PPP.

(+)[3H]SKF 10,047 and (+)[3H]3-PPP label a homogeneous population of sites in NCB-20 cell membranes that apparently represent benzomorphan specific binding sites previously reported for this cell line. Their drug specificity indicates that these sites are very similar to sigma receptor binding sites labeled in brain tissues by these ligands and do not represent PCP receptors.