Characterization of excitatory amino acid neurotoxicity in N-methyl-D-aspartate receptor-deficient mouse cortical neuronal cells.
Roles and mechanisms of N-methyl-D-aspartate (NMDA) receptors in glutamate neurotoxicity were investigated in cultures of NMDA receptor-deficient cortical neuronal cells. Mutant mice lacking a functional NMDA receptor were generated by gene targeting of the NR1 NMDA receptor subunit. Cortical neuronal cells prepared from wild-type NR1+/+, heterozygous NR1+/- and homozygous mutant NR1-/- mice at 15-17 days of gestation grew indistinguishably from each other. Brief exposures (5 min) of both NR1+/+ and NR1+/- neuronal cells to glutamate or NMDA, but not kainate or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), resulted in widespread neuronal degeneration by the following day. In contrast, neither glutamate nor NMDA treatment caused neuronal degeneration in NR1-/- cells, indicating that NMDA receptors are responsible for rapidly triggered glutamate neurotoxicity. The above four compounds were all effective in inducing the death of NR1+/+ and NR1+/- neuronal cells after prolonged exposure (20-24 h). However, NMDA had no neurotoxic effects on NR1-/- cells, although the other three compounds wer neurotoxic with potencies comparable to those for NR1+/+ and NR1+/- cells. The AMPA and kainate receptors are thus sufficient for inducing slowly triggered glutamate neurotoxicity. Brief exposure of a mixed population of NR1+/+ and NR1-/- neuronal cells to NMDA selectively killed the NMDA receptor-expressing cells without any appreciable effects on neighbouring NMDA receptor-deficient cells. This finding further supports a direct and indispensable role for NMDA receptors in NMDA-evoked neuronal cell death.
Tokita
Y
Y
Institute for Immunology, Kyoto University Faculty of Medicine, Japan.
Bessho
Y
Y
Masu
M
M
Nakamura
K
K
Nakao
K
K
Katsuki
M
M
Nakanishi
S
S
D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D002678:Chimera; D005260:Female; D018698:Glutamic Acid / Q000633:toxicity*; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D008818:Mice, Neurologic Mutants; D016202:N-Methylaspartate / Q000633:toxicity; D009474:Neurons / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D009498:Neurotoxins / Q000633:toxicity*; D018091:Receptors, AMPA / Q000502:physiology; D018092:Kainic Acid Receptors / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000502:physiology*; D013234:Stem Cells; D014162:Transfection
D018698:Glutamic Acid; D016202:N-Methylaspartate; D009498:Neurotoxins; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate