Presence of N-methyl-D-aspartate (NMDA) receptors in neuroblastoma x glioma hybrid NG108-15 cells-analysis using [45Ca2+]influx and [3H]MK-801 binding as functional measures.
In the present study, we have attempted to clarify whether neuroblastoma glioma hybrid NG 108-15 cells (NG cells) possess the NMDA receptor complex using [45Ca2+]influx and [3H]MK-801 binding as functional measures. Glutamate and NMDA dose-dependently increased [45Ca2+]influx and these increases were further enhanced by glycine. Scatchard analysis revealed the presence of a high-affinity binding site for [3H]MK-801 with a KD of 18.8 nM and a Bmax of 0.328 pmol/mg protein. This [3H]MK-801 binding was also increased by NMDA in a dose-dependent manner and this increase was further enhanced by glycine. Both ketamine and MK-801 inhibited glutamate- and NMDA-induced [45Ca2+]influx as well as the increase of [3H]MK-801 binding in a dose-dependent manner. Similarly, Mg2+ and Zn2+ dose-dependently reduced both glutamate-induced [45Ca2+]influx and [3H]MK-801 binding. Spermine, one of the polyamines, showed a biphasic stimulatory effects on glutamate-induced [45Ca2+]influx and [3H]MK-801 binding. These results indicate that NG cells possess a pharmacologically distinct NMDA receptor complex and suggest that these cells may be useful for the analyses on pharmacological and biochemical characteristics of the NMDA receptor complex.
Ohkuma
S
S
Department of Pharmacology, Kyoto Prefectural University of Medicine, Japan.
Katsura
M
M
Chen
D Z
DZ
Chen
S H
SH
Kuriyama
K
K
D002132:Calcium Radioisotopes; D002413:Cations, Divalent / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000378:metabolism*; D005910:Glioma / Q000737:chemistry; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D005998:Glycine / Q000494:pharmacology; D006822:Hybrid Cells / Q000737:chemistry*; D016202:N-Methylaspartate / Q000494:pharmacology; D009447:Neuroblastoma / Q000737:chemistry; D011869:Radioligand Assay; D016194:Receptors, N-Methyl-D-Aspartate / Q000032:analysis*; D013096:Spermine / Q000494:pharmacology; D014316:Tritium
D002132:Calcium Radioisotopes; D002413:Cations, Divalent; D005971:Glutamates; D016194:Receptors, N-Methyl-D-Aspartate; D014316:Tritium; D013096:Spermine; D018698:Glutamic Acid; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D005998:Glycine