title: Detection of delta opioid receptor and N-methyl-D-aspartate receptor-like immunoreactivity in retinoic acid-differentiated neuroblastoma x glioma (NG108-15) cells.
abstract: NG108-15 neuroblastoma cells differentiated with 0.1 M of all-trans retinoic acid (RA) were processed for immunohistochemical analysis using polyclonal antisera against the delta opioid receptor (DOR) and the N-Methyl-D-Aspartate receptor (NMDAR1) to determine the cellular sites for possible functional associations between DOR and NMDAR1 receptors. In this study, 6 days of RA treatment resulted in prominent morphological differentiation characterized by the appearance of numerous axon- and dendrite-like processes and formation of networks between the cell clusters. An immunocytochemical approach allowed the demonstration of antibody concentration-dependent differences, not evident in ligand binding studies, in the distribution of DOR and NMDA receptor protein between cell soma and processes. RA-differentiated cultures showed positive DOR-like immunostaining (DOR-LI) throughout the cell bodies as well as on the newly acquired processes. In contrast, NMDAR1-like immunoreactivity (NMDAR1-LI) in the RA-treated cells was detected in the cell soma and processes only with the higher concentration of the antiserum. With the lower concentration of the antibody the NMDAR1-LI was not detected in the processes and was limited to a punctuate subcellular distribution in the soma. The DOR-LI pattern of distribution in NG108-15 cells differentiated with RA appeared to be consistent with the DOR-LI detected in the CNS. The NMDAR1-LI distribution in these cells is similar to brain tissue with respect to its presence on the newly acquired processes. However, it differed from brain in that a much higher abundance of NMDAR1 receptors was observed in the cell soma. This differential distribution of DOR and NMDAR1 receptors in the RA-treated NG108-15 cells could provide a basis for future studies of drug-induced changes in these two receptors.
authors.affiliation: Department of Pharmacology, Cornell University Medical College, New York 10021, USA.
authors.forename: I W
authors.initials: IW
authors.lastname: Beczkowska
authors.forename: K N
authors.initials: KN
authors.lastname: Gracy
authors.forename: V M
authors.initials: VM
authors.lastname: Pickel
authors.forename: C E
authors.initials: CE
authors.lastname: Inturrisi
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D000970:Antineoplastic Agents / Q000494:pharmacology; D001369:Axons / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D003712:Dendrites / Q000187:drug effects; D005910:Glioma; D006822:Hybrid Cells / Q000737:chemistry / Q000166:cytology / Q000648:ultrastructure; D007124:Immunoenzyme Techniques; D051379:Mice; D009447:Neuroblastoma; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000032:analysis* / Q000276:immunology; D017465:Receptors, Opioid, delta / Q000032:analysis* / Q000276:immunology; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D016194:Receptors, N-Methyl-D-Aspartate; D017465:Receptors, Opioid, delta; D014212:Tretinoin