title: Cell-free desensitization of opioid inhibition of adenylate cyclase in neuroblastoma X glioma NG108-15 hybrid cell membranes.
abstract: When membranes from neuroblastoma X glioma NG108-15 hybrid cells were incubated in a cell-free system with opioid agonists, a time-, temperature-, and dose-dependent desensitization to opioid inhibition of adenylate cyclase activity was observed. The composition of the system during the incubation was manipulated to elucidate the biochemical mechanisms of desensitization. Receptor coupling appeared to be a prerequisite for desensitization, because both magnesium and sodium, which are necessary for coupling, were required for desensitization. Removal of ATP and addition of cyclic AMP or cyclic GMP had no effect on desensitization.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000067956:Adenylyl Cyclase Inhibitors; D000527:Alprostadil / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D002474:Cell-Free System; D004723:Endorphins / Q000494:pharmacology*; D005048:Etorphine / Q000494:pharmacology; D005910:Glioma / Q000201:enzymology*; D006822:Hybrid Cells / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D009447:Neuroblastoma / Q000201:enzymology*; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology; D012964:Sodium / Q000494:pharmacology
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D004723:Endorphins; D011957:Receptors, Opioid; D005048:Etorphine; D000255:Adenosine Triphosphate; D012964:Sodium; D000527:Alprostadil; D008274:Magnesium