F11 neuroblastoma × DRG neuron hybrid cells express inhibitory μ- and δ-opioid receptors which increase voltage-dependent K+ currents upon activation

摘要: The F11 cell line is a fusion product of cells mouse neuroblastoma N18TG-2 with embryonic rat dorsal-root ganglion (DRG) neurons. Previous biochemical results suggest that they express mu- and delta-opioid receptors are negatively coupled to adenylate cyclase. present study provides direct agonist-binding electrophysiologic evidence mu delta, but not kappa, receptor expression in cells. Radioligand binding assays show membranes bind the agonists, DAGO DPDPE Kd = 4.5 4.9 nM Bmax 111 195 fmol/mg, respectively. Tight-seal patch-clamp recordings after several days differentiating culture medium (low serum, cyclic AMP nerve growth factor) showed that: (i) outward K+ current during pulsed depolarization most these was increased by either or DPDPE, none were responsive both opioids kappa-opioid agonist, U-50,488H. response blocked relevant antagonists, naloxone, beta-funaltrexamine naltrindole; (ii) without processes responded neither nor DPDPE; (iii) treatment pertussis toxin all opioid-induced increases current. increase voltage-dependent membrane resembles inhibitory effect elicited agonists primary cultures DRG