Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
PLoS One. 2013 Apr 11;8(4):e60892. doi: 10.1371/journal.pone.0060892. Print 2013.
Nogo Receptor 1 (NgR1) mRNA is downregulated in hippocampal and cortical regions by increased neuronal activity such as a kainic acid challenge or by exposing rats to running wheels. Plastic changes in cerebral cortex in response to loss of specific sensory inputs caused by spinal cord injury are also associated with downregulation of NgR1 mRNA. Here we investigate the possible regulation by neuronal activity of the homologous receptors NgR2 and NgR3 as well as the endogenous NgR1 antagonist LOTUS and the ligand Nogo. The investigated genes respond to kainic acid by gene-specific, concerted alterations of transcript levels, suggesting a role in the regulation of synaptic plasticity, Downregulation of NgR1, coupled to upregulation of the NgR1 antagonist LOTUS, paired with upregulation of NgR2 and 3 in the dentate gyrus suggest a temporary decrease of Nogo/OMgp sensitivity while CSPG and MAG sensitivity could remain. It is suggested that these activity-synchronized temporary alterations may serve to allow structural alterations at the level of local synaptic circuitry in gray matter, while maintaining white matter pathways and that subsequent upregulation of Nogo-A and NgR1 transcript levels signals the end of such a temporarily opened window of plasticity.
神经生长抑制因子受体 1（NgR1）mRNA 可被神经元活动所下调，如通过给予红藻氨酸或让大鼠跑转轮可使海马和皮质区的 NgR1mRNA 下调。脊髓损伤导致特定感觉传入缺失所引起的大脑皮层的可塑性变化也与 NgR1mRNA 的下调有关。在这里，我们研究了神经元活性对同源受体 NgR2 和 NgR3 以及内源性 NgR1 拮抗剂 LOTUS 和配体 Nogo 的可能调节作用。研究的基因通过转录水平的特异性协同变化对红藻氨酸作出反应，提示其在调节突触可塑性中起作用。NgR1 的下调与 NgR1 拮抗剂 LOTUS 的上调相偶联，同时齿状回的 NgR2 和 3 上调提示 Nogo/OMgp 敏感性暂时降低，而 CSPG 和 MAG 敏感性可能保持不变。因此，这些与活性同步的暂时改变可能有助于维持灰质局部突触回路的结构改变，同时保持白质通路，随后 Nogo-A 和 NgR1 转录水平的上调表明这种暂时开放的可塑性窗口的结束。
