Chase M H, Morales F R, Boxer P A, Fung S J
Exp Neurol. 1985 Nov;90(2):471-8. doi: 10.1016/0014-4886(85)90035-4.
The aging of spinal cord alpha motoneurons was explored in old cats with intracellular recording techniques to determine the basic membrane properties of these neurons and their monosynaptic response following activation of group Ia afferent fibers. The conduction velocity of the motoneurons' axons decreased in old animals (14 to 15 years of age) compared with adult controls (1 to 3 years of age). The input resistance of the motoneurons increased in the old cats; no change occurred in the resting membrane potential or spike amplitude. There was a reduction in the delay between the initial segment and the somadendritic components of the antidromic spike. The half-width duration of the monosynaptic EPSP in the old cats increased, but its amplitude did not change. These data indicate that a host of different membrane properties of spinal cord motoneurons and their Ia-monosynaptic input are affected by the aging process. Analysis of the results suggests that the degradation of neuronal processes occurs in all motoneurons rather than preferentially affecting a specific population of motoneurons.
采用细胞内记录技术，对老年猫脊髓α运动神经元的老化情况进行了研究，以确定这些神经元的基本膜特性及其在Ia类传入纤维激活后的单突触反应。与成年对照动物（1至3岁）相比，老年动物（14至15岁）运动神经元轴突的传导速度下降。老年猫运动神经元的输入电阻增加；静息膜电位或动作电位幅度未发生变化。逆向动作电位的起始段与胞体树突成分之间的延迟缩短。老年猫单突触兴奋性突触后电位的半宽度持续时间增加，但其幅度未改变。这些数据表明，脊髓运动神经元的许多不同膜特性及其Ia单突触输入均受衰老过程的影响。结果分析表明，神经元突起的退化发生在所有运动神经元中，而非优先影响特定群体的运动神经元。
