Greensmith L, Hasan H I, Vrbová G
Department of Anatomy and Developmental Biology, University College, London, U.K.
Neuroscience. 1994 Feb;58(4):727-33. doi: 10.1016/0306-4522(94)90450-2.
If the sciatic nerve is crushed in neonatal rats, a large proportion of motoneurons die, but the same injury inflicted at five days of age results in little, if any, motoneuron death. However, these motoneurons are rendered susceptible to the excitotoxic effects of the glutamate agonist, N-methyl-D-aspartate. Retrograde labelling of soleus motoneurons after nerve crush at five days of age, followed by treatment with N-methyl-D-aspartate seven days later, shows that only 36 +/- 7.5% of motoneurons have survived. If the motoneurons are allowed to reinnervate their target, and N-methyl-D-aspartate is applied three weeks after the nerve injury, no motoneuron death is observed. Furthermore, adult motoneurons remain resistant to the toxic effects of N-methyl-D-aspartate, even after nerve injury. These results indicate that glutamate, the main excitatory neurotransmitter in the developing spinal cord, may be involved in the motoneuron death that occurs following nerve injury during early postnatal development.
如果在新生大鼠中坐骨神经被挤压，很大一部分运动神经元会死亡，但在出生五天时遭受同样的损伤，即使有运动神经元死亡，数量也极少。然而，这些运动神经元会变得易受谷氨酸激动剂N-甲基-D-天冬氨酸的兴奋毒性作用影响。在出生五天时对比目鱼肌运动神经元进行神经挤压后逆行标记，七天后用N-甲基-D-天冬氨酸处理，结果显示只有36±7.5%的运动神经元存活下来。如果让运动神经元重新支配它们的靶标，并在神经损伤三周后应用N-甲基-D-天冬氨酸，则未观察到运动神经元死亡。此外，即使在神经损伤后，成年运动神经元对N-甲基-D-天冬氨酸的毒性作用仍具有抗性。这些结果表明，谷氨酸作为发育中的脊髓中的主要兴奋性神经递质，可能与出生后早期发育期间神经损伤后发生的运动神经元死亡有关。
