Role of neuronal NR2B subunit-containing NMDA receptor-mediated Ca2+ influx and astrocytic activation in cultured mouse cortical neurons and astrocytes.
The excitatory neurotransmitter glutamate has been shown to mediate such bidirectional communication between neurons and astrocytes. In the present study, we determined the role of N-methyl-D-aspartate (NMDA) receptors on glutamate-evoked Ca(2+) influx into neurons and astrocytes. Either a nonselective NMDA receptor antagonist (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801) or selective NR2B subunit-containing NMDA receptor antagonists ifenprodil and (R,S)-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenylmethyl)-1-piperid inepropanol (Ro25-6981) significantly inhibited the glutamate-evoked Ca(2+) influx into neurons, but not into astrocytes. Furthermore, we investigated whether NR2B subunit-containing NMDA receptor antagonists could suppress the astrocytic activation, as detected by glial fibrillary acidic protein (GFAP; as a specific marker of astrocyte)-like immunoreactivities in mouse cortical astrocytes. Here, we demonstrated that the increases in the level of GFAP-like immunoreactivities induced by glutamate were markedly suppressed by cotreatment with ifenprodil in cortical neuron/glia cocultures, but not in purified astrocytes. These results suggest that NR2B subunit-containing NMDA receptor plays a critical role in not only glutamate-evoked Ca(2+) influx into neurons, but also glutamate-induced astrocytic activation. Thus, glutamate-mediated pathway via NR2B subunit-containing NMDA receptor may, at least in part, contribute to neuron-to-astrocyte signaling.
Kato
Hideaki
H
Department of Toxicology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Shinagawa-ku, Tokyo, Japan.
Narita
Minoru
M
Miyatake
Mayumi
M
Yajima
Yoshinori
Y
Suzuki
Tsutomu
T
D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D004347:Drug Interactions; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology; D007150:Immunohistochemistry / Q000379:methods; D051379:Mice; D008813:Mice, Inbred ICR; D018613:Microscopy, Confocal / Q000379:methods; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D014966:Xanthenes / Q000378:metabolism
D000814:Aniline Compounds; D018691:Excitatory Amino Acid Antagonists; D005904:Glial Fibrillary Acidic Protein; C121001:NR2B NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate; D014966:Xanthenes; C059715:Fluo-3; D018698:Glutamic Acid; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D002118:Calcium