title: Delta and sigma sites of clonal NCB20 cells do not modulate calcium uptake.
abstract: Opiate alkaloids and peptides are reported to inhibit 45Ca2+ binding to synaptic plasma membranes and uptake into brain synaptosomes. We have examined the effects of a number of opiates on 45Ca2+ uptake in a clonal cell line NCB20 which expresses multiple opioid binding sites. The cells express voltage-dependent calcium channels that are blocked by verapamil and nifedipine. In contrast to brain, 45Ca2+ uptake in these cells, in normal or high potassium medium, is unaffected by opiates. This difference may be due to the particular receptor types; the delta and sigma sites of these cells do not inhibit 45Ca2+ uptake.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002999:Clone Cells; D004723:Endorphins / Q000494:pharmacology; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D009294:Narcotics / Q000494:pharmacology; D011957:Receptors, Opioid / Q000378:metabolism*; D017480:Receptors, sigma
chemical_list: D004723:Endorphins; D007473:Ion Channels; D009294:Narcotics; D011957:Receptors, Opioid; D017480:Receptors, sigma; D002118:Calcium