Evidence for mu-, delta-, and kappa-opioid receptors in a human neuroblastoma cell line

Human neuroblastoma cells were tested for the presence of opioid receptors. [3H]Diprenorphine binds to NMB cell membranes with a KD value of 0.46 +/- 0.13 nM and Bmax of 534 +/- 22 fmol/mg protein. The presence of mu, delta, and kappa opioid receptors was tested by displacing [3H]diprenorphine specific binding by the selective agonists DAMGO, DPDPE, and U50,488H, respectively. Using this procedure, the data suggest that the NMB neuroblastoma cells express the three opioid receptor types with the abundance of delta receptors (about 60%) and minor, yet substantial populations of mu and kappa receptors (about 20% each).