Acute hypoxia differentially affects the NMDA receptor NR1, NR2A and NR2B subunit mRNA levels in the developing chick optic tectum: stage-dependent plasticity in the 2B-2A ratio.
It is known that the NMDA-R NR1 subunit is needed for the receptor activity and that under hypoxia the evolution toward apoptosis or neuronal survival depends on the balance NR2A/NR2B subunits. This paper analyzes the effect of acute hypoxia on the above mentioned subunits mRNAs during development. The mean percentage of NR1+ neurons displayed the higher plasticity during development while the NR2A+ neurons the higher stability. Acute hypoxia increased the mean percentage of NR1+ and NR2B+ neurons at ED12 but only that of NR1+ neurons at ED18. Acute hypoxia increased the levels of expression of NR1 and NR2B mRNAs at ED12 without changes in the NR2A mRNA. During early stages there is a higher sensitivity to change the subunits mRNA levels under a hypoxic treatment. At ED12 acute hypoxia increased the probability of co-expression of the NR1-NR2A and NR1-NR2B subunits combinations, the level of NR1 and NR2B and the ratio NR2B/NR2A. These conditions facilitate the evolution towards apoptosis.
Vacotto
Marina
M
Institute of Cell Biology and Neuroscience Prof. E. De Robertis, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina.
Rapacioli
Melina
M
Flores
Vladimir
V
de Plazas
Sara Fiszer
SF
D000818:Animals; D002642:Chick Embryo; D002534:Hypoxia, Brain / Q000378:metabolism*; D066298:In Vitro Techniques; D012333:RNA, Messenger / Q000096:biosynthesis*; D016194:Receptors, N-Methyl-D-Aspartate / Q000096:biosynthesis* / Q000235:genetics; D013477:Superior Colliculi / Q000196:embryology / Q000378:metabolism*
C409466:NR1 NMDA receptor; C120997:NR2A NMDA receptor; C121001:NR2B NMDA receptor; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate