Nerve injury in adult rats causes abnormalities in the motoneuron dendritic field that differ from those seen following neonatal nerve injury
Nerve injury in adult rats causes abnormalities in the motoneuron dendritic field that differ from those seen following neonatal nerve injury
复制标题
成年大鼠的神经损伤导致运动神经元树突状区域异常，与新生大鼠神经损伤后观察到的异常不同
作者：
G. O’Hanlon;M. Lowrie
在出生后早期，神经挤压导致神经肌肉接触中断，导致受影响运动神经元的活动增加和异常反射反应，但成年动物在神经挤压后没有发现这种变化。我们先前发现，新生儿受损的细胞发育异常的树突区，这可能解释了功能变化。在这里，我们研究了成熟时神经挤压后同一运动神经元池的树突形态，以将观察到的形态变化与生理结果相关联。在成年动物坐骨神经挤压后1~2个月，用霍乱毒素B亚单位与辣根过氧化物酶结合逆行标记大鼠拇长伸肌运动神经元。然后对标记细胞的树突树进行了分析。成年神经挤压后，运动神经元的树突树较小，但没有表现出新生儿神经挤压后局部树突密度的增加。这些发现支持了这样一种观点，即这种特殊的形态变化导致了只有在新生儿神经损伤后才能看到的生理异常。
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.