皮质脊柱体损伤后的超反射反应反映了1A afferent电路的变化没有增加KCC2过度兴奋性
bioRxiv : the preprint server for biology
|March 3, 2025
概括
脊髓损伤后的过度反射症涉及自感性 afferent (PA) 芽和减少GABAergic抑制 (GABApre). 这项研究发现前肢反射过度与PA发芽和宫运动神经元中未补偿的GABApre有关,而不是KCC2变化.
科学领域:
- 神经科学是一个神经科学.
- 脊髓损伤研究 脊髓损伤研究
- 运动系统生理学运动系统生理学
背景情况:
- 过度反射是脊髓损伤 (SCI) 和大脑运动系统病变的常见后果.
- 提出的关键机制包括自身感应接体 (PA) 电路变化 (例如,1A纤维发芽) 和减少GABAergic前突触抑制 (GABApre),以及改变的运动神经元内在兴奋性 (例如,减少KCC2).
- 区分这些机制对超反射症的贡献一直是具有挑战性的.
研究的目的:
- 为了调查PA电路变化和GABAergic调节对选择性单边皮质脊柱管 (CST) 损伤后的超反射症的特定贡献.
- 确定运动神经元内在刺激能力,特别是KCC2水平在超反射症发展中的作用.
- 为了检查单边金字塔切除术 (PTX) 后的超反射和潜在机制的时间过程和横向性.
主要方法:
- 选择性单边金字塔切除术 (PTX) 在老鼠中,以消除来自一个半球的CST输入.
- 使用前肢和后肢肌肉中霍夫曼 (H) 反射的速度依赖性抑郁 (RDD) 在受伤后的不同时间点 (7dpi和42dpi) 评估超反射症.
- 对PA突触 (VGlut1),GABA前突触终端 (GABApre),运动神经元 (ChAT) 和部和腰部脊髓中的KCC2表达的免疫组合化学分析.
主要成果:
- 只有在单边PTX后,在缩前肢中才观察到显著的反射.
- 虽然宫和腰部运动神经元都显示了增加的PA芽,但只有腰部运动神经元表现出GABApre终端的同时增加,与正常的后肢H反射相关.
- 膜结合的KCC2水平在逆伤性宫运动神经元中保持不变,在这个模型中将KCC2与前肢反射症分离出来.
结论:
- 在单边PTX模型中,前肢反射反应主要是由宫运动神经元中芽的自感 afferent (PA) 驱动的.
- 这种超反射症与宫水平的GABAergic前突触抑制 (GABApre) 的未补偿降低有关.
- 减少的运动神经元KCC2在这种特定的中枢神经系统损伤模型中,不是显著的反应过度的贡献者.
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