O'Hanlon G M, Lowrie M B
Department of Anatomy and Cell Biology, St. Mary's Hospital Medical School, Imperial College, London, UK.
Exp Brain Res. 1995;103(2):243-50. doi: 10.1007/BF00231710.
Disruption of neuromuscular contact by nerve-crush during the early postnatal period causes increased activity and abnormal reflex responses in affected motoneurons, but such changes are not found after nerve-crush in adult animals. We found previously that neonatally lesioned cells develop an abnormal dendritic field, which may explain the functional changes. Here we have studied the dendritic morphology of the same motoneuron pool after nerve-crush at maturity in order to correlate the observed alterations in morphology with physiological findings. One to two months after sciatic nerve-crush in adult animals, motoneurons supplying the extensor hallucis longus muscles of the rat were retrogradely labelled with cholera toxin subunit-B conjugated to horseradish peroxidase. The dendritic tree of labelled cells was then analysed. Following adult nerve-crush, the dendritic tree of the motoneurons was smaller but did not display the localised increase in dendritic density seen after neonatal nerve-crush. These findings support the view that such specific morphological changes contribute to the physiological abnormalities seen only after neonatal nerve injury.
出生后早期神经挤压导致神经肌肉接触中断，会使受影响的运动神经元活动增加且反射反应异常，但成年动物神经挤压后未发现此类变化。我们之前发现，新生期受损的细胞会形成异常的树突场，这可能解释了功能变化。在此，我们研究了成年期神经挤压后同一运动神经元池的树突形态，以便将观察到的形态改变与生理结果相关联。成年动物坐骨神经挤压一到两个月后，用与辣根过氧化物酶偶联的霍乱毒素B亚基对支配大鼠拇长伸肌的运动神经元进行逆行标记。然后分析标记细胞的树突树。成年神经挤压后，运动神经元的树突树较小，但未显示出新生期神经挤压后出现的树突密度局部增加。这些发现支持这样一种观点，即这种特定的形态变化导致了仅在新生期神经损伤后出现的生理异常。
