Landry E S, Rouillard C, Levesque D, Guertin P A
Neuroscience Unit, Laval University Medical Center, Quebec City, PQ, Canada.
Behav Neurosci. 2006 Dec;120(6):1384-8. doi: 10.1037/0735-7044.120.6.1384.
Induction of immediate early gene (IEG) expression is believed to constitute one of the earliest steps in plasticity and long-term modification of neuronal properties. Although behavioral evidence of neuronal plasticity at the sublesional level after spinal cord injury exists, spatiotemporal changes of IEGs in spinal segments located caudally to such an injury have never been examined. Here, the authors studied spatiotemporal changes of c-fos, nor-1, nur77, nurr1, and retinoid x receptor (rxr) messenger RNA expression in the lumbar segments L1-L2 after low-thoracic spinal transection (Tx). C-fos expression generally increased in the dorsal horn with significant levels reached at 3 days and 14 days post-Tx. Basal nor-1 transcript levels decreased in the intermediate zone and dorsal horn areas at 7 days. Nur77 levels were nonsignificantly depressed throughout that period of time, whereas nurr1 and rxr transcripts were not detected before or after Tx. In conclusion, the results provide evidence of distinct roles for c-fos and nor-1 in reorganization and plasticity of neuronal networks typically involved in sensorimotor integration and locomotor control.
即刻早期基因（IEG）表达的诱导被认为是神经元特性可塑性和长期改变的最早步骤之一。尽管脊髓损伤后在损伤水平以下存在神经元可塑性的行为学证据，但在此类损伤尾侧脊髓节段中IEG的时空变化从未被研究过。在此，作者研究了胸段低位脊髓横断（Tx）后腰段L1-L2中c-fos、nor-1、nur77、nurr1和视黄酸X受体（rxr）信使RNA表达的时空变化。c-fos表达通常在背角增加，在Tx后3天和14天达到显著水平。在第7天，中间带和背角区域的基础nor-1转录水平下降。在那段时间里，Nur77水平无显著降低，而在Tx前后均未检测到nurr1和rxr转录本。总之，这些结果为c-fos和nor-1在通常参与感觉运动整合和运动控制的神经元网络重组和可塑性中的不同作用提供了证据。
