Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha 410008, Hunan Province, China.
Neural Regen Res. 2012 Jan 5;7(1):13-7. doi: 10.3969/j.issn.1673-5374.2012.01.002.
Nogo-A and Nogo receptor (NgR) expression in the visual cortex following a critical developmental period (postnatal days 20-60) has been previously shown. However, little is known regarding Nogo-A and NgR expression between postnatal day 0 and initiation of the critical period. The present study analyzed Nogo-A and NgR expression at four different time points: postnatal day 0 (P0), before critical period (P14), during critical period (P28), and after critical period (P60). Results showed significantly increased Nogo-A mRNA and protein expression levels in the visual cortex following birth, and expression levels remained steady between P28 and P60. NgR mRNA or protein expression was dramatically upregulated with age and peaked at P14 or P28, respectively, and maintained high expression to P60. In addition, Nogo-A and NgR expression was analyzed in each visual cortex layer in normal developing rats and rats with monocular deprivation. Monocular deprivation decreased Nogo-A and NgR mRNA and protein expression in the rat visual cortex, in particular in layers II-III and IV in the visual cortex contralateral to the deprived eye. These findings suggested that Nogo-A and NgR regulated termination of the critical period in experience- dependent visual cortical plasticity.
已先前显示，在关键发育期（出生后第 20-60 天）之后，视皮层中存在 Nogo-A 和 Nogo 受体（NgR）表达。然而，对于关键期开始之前的出生后第 0 天（P0）至关键期之间的 Nogo-A 和 NgR 表达，知之甚少。本研究在四个不同时间点分析了 Nogo-A 和 NgR 的表达：出生后第 0 天（P0）、关键期前（P14）、关键期内（P28）和关键期后（P60）。结果显示，出生后视皮层中 Nogo-A mRNA 和蛋白表达水平显著增加，并且 P28 与 P60 之间的表达水平保持稳定。NgR mRNA 或蛋白表达随年龄增长而显著上调，分别在 P14 或 P28 时达到峰值，并在 P60 时维持高表达。此外，在正常发育的大鼠和单眼剥夺的大鼠中分析了视皮层各层中的 Nogo-A 和 NgR 表达。单眼剥夺降低了大鼠视皮层中的 Nogo-A 和 NgR mRNA 和蛋白表达，特别是在对侧剥夺眼的视皮层的 II-III 和 IV 层中。这些发现表明，Nogo-A 和 NgR 调节经验依赖性视皮质可塑性中关键期的结束。
