Evidence for nuclear sites of stereospecific opiate binding in neuroblastoma cells in continuous culture.
A class of stereospecific, saturable receptors for narcotic drugs has been found in a clone of mouse neuroblastoma cells in continuous culture. Cells grown in the presence of 10(-8) M etorphine, a synthetic opiate, had an increased doubling time. The neuroblastoma cell nucleus was found to be the sole site for the high affinity binding of etorphine. It was found that these nuclear receptors (1) became saturated at a concentration of 2 X 10(-9) M etorphine, (2) had a dissociation constant of 5 X 10(-11) M etorphine, (3) were capable of binding etorphine stereospecifically at 37 degrees C but not at 4 degree C, and t4) were protein in nature as evidenced by treatment with proteolytic enzymes. More importantly, the receptor activity appeared to be chromatin-associated.
D000818:Animals; D001667:Binding, Competitive; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005048:Etorphine / Q000378:metabolism; D006367:HeLa Cells / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D008861:Microsomes / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism; D011957:Receptors, Opioid / Q000378:metabolism*
D002843:Chromatin; D011957:Receptors, Opioid; D005048:Etorphine