Astrocytes express N-methyl-D-aspartate receptor subunits in development, ischemia and post-ischemia.
The expression of the N-methyl-D-aspartate receptor (NMDA-R) in astrocytes is controversial. The receptor is commonly considered neuron-specific. We showed that astrocytes in primary cultures differentially expressed mRNA of NMDA-R subunits, NR1, NR2A and NR2B, in development, ischemia and post-ischemia. One-week-old cultures expressed detectable NR1 mRNA, which fell significantly at 2 weeks and became barely detectable at 4 weeks. NR2A and NR2B mRNA were both significantly up-regulated from 1 to 2 weeks. In 4 weeks, 2 h of ischemia caused a significant up-regulation of NR1 and NR2B mRNA; while 6 h caused down-regulation of NR2A mRNA. Under 3 h of post-ischemia, only NR1 mRNA was increased. Ischemia induced the expression of major NMDA-R effecter, nitric oxide synthase 1, which was unaffected by AMPA-R antagonist CNQX, but dose-dependently inhibited by NMDA-R specific antagonist MK-801. These findings reflected that astrocyte could express inducible functional NMDA receptors without the presence of neurons.
Neuroscience Research Institute, Peking University, 100191 Beijing, China.
Ye
Y
Zhou
Hui Li
HL
Li
Rui
R
Zhao
Li Tao
LT
Yang
Yan
Y
Dong
Xin
X
Yue
Yao Ying
YY
Ma
Zhuo
Z
Wang
Jianguo
J
Chen
Cai Lian
CL
Cui
Albert Cheung-Hoi
AC
Yu
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D015536:Down-Regulation; D005455:Fluorescent Antibody Technique; D018698:Glutamic Acid / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051379:Mice; D008813:Mice, Inbred ICR; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D006861:Hydrogen Peroxide; D052248:Nitric Oxide Synthase Type I; C496321:Nos1 protein, mouse