The distinct role of NR2B subunit in the enhancement of visual plasticity in adulthood.
BACKGROUND
Experience-dependent plasticity is confined to the critical period of early postnatal life, and declines dramatically thereafter. This attenuation promotes the stabilization of cortical circuits, but also limits functional recovery of several brain diseases. The cognitive functions and synaptic plasticity in the hippocampus and prefrontal cortex are elevated following chronic magnesium treatment. Here, we explored the effect of magnesium treatment on visual plasticity and the potential clinical significance.


RESULTS
Visual plasticity in adult mice was dramatically enhanced following magnesium treatment, which was concurrent with an increase in the expression of NR2 subunits of N-methyl-D-aspartate receptors. Blockade of NR2B activity in both the induction and expression periods of plasticity prevented this reinstatement. However, the plasticity restored via a decrease in cortical inhibition was independent on the activation of NR2B, indicating a different underlying mechanism. The functional excitatory synapses on layer 2/3 pyramidal neurons were increased following magnesium supplementation. Moreover, the synaptic and neuronal responses were reminiscent of that within the critical period, and this rejuvenation of adult visual cortex facilitated the recovery of visual functions in amblyopia.


CONCLUSIONS
Collectively, our data reveal two distinct mechanisms underlying the restoration of visual plasticity in adulthood, and the rejuvenation of adult visual cortex following magnesium treatment provides a new avenue to develop clinical therapies for adult amblyopia, as well as to explore plasticity-based treatment of other brain diseases, such as stroke and aphasia.
Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.|Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230027, China.
Hanxiao
H
Liu
Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.
Yue
Y
Li
Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.
Yan
Y
Wang
Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.
Xinxing
X
Wang
Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.
Xu
X
An
School of Basic Medicine, Anhui Medical University, Hefei, 230032, China.
Siying
S
Wang
Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.|Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230027, China.
Lin
L
Chen
Tsinghua-Peking Centre for Life Sciences, School of Medicine, Tsinghua University, Beijing, 100084, China.
Guosong
G
Liu
Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China. yangyp@ustc.edu.cn.
Yupeng
Y
Yang
D000375:Aging / Q000378:metabolism*; D000550:Amblyopia / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D008274:Magnesium / Q000494:pharmacology; D008810:Mice, Inbred C57BL; D009473:Neuronal Plasticity; D021122:Protein Subunits / Q000378:metabolism*; D017966:Pyramidal Cells / Q000187:drug effects / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D014793:Visual Cortex / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology
C121001:NR2B NMDA receptor; D021122:Protein Subunits; D016194:Receptors, N-Methyl-D-Aspartate; D008274:Magnesium