Morrison E E, Costanzo R M
Department of Physiology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0551, USA.
Neurosci Lett. 1995 Oct 6;198(3):213-7. doi: 10.1016/0304-3940(95)11943-q.
Olfactory neuron recovery and axon growth was studied in 12-24 month old hamsters after unilateral olfactory nerve transection. At recovery times ranging from 4 to 126 days olfactory nerve regeneration and axon reconnection to the olfactory bulb were examined by anterograde horseradish peroxidase (HRP) neurohistochemistry and electron microscopy. Nerve transection produced immediate retrograde neuron degeneration and there was no HRP reaction product in the bulb at 4 days post transection. By day 35, centrally growing olfactory axons had reached the bulb. Axons formed glomeruli smaller than those in the unoperated control bulb and they were not always confined to the glomerular layer of the bulb. Some animals showed robust fiber growth with axon fascicles penetrating the different layers of the bulb and forming ectopic glomeruli along their path. Second order bulb neurons contained wheat germ agglutinin HRP reaction product, indicating that transneuronal transport had occurred. Electron microscopy confirmed transneuronal transport between olfactory axons and second order bulbar neurons. These results show that the capacity for olfactory neuron recovery and reconnection persists in the hamster well into old age.
在12至24月龄的仓鼠单侧嗅神经横断后，对其嗅觉神经元恢复和轴突生长进行了研究。在4至126天的恢复时间内，通过顺行辣根过氧化物酶（HRP）神经组织化学和电子显微镜检查嗅神经再生以及轴突与嗅球的重新连接情况。神经横断导致立即出现逆行性神经元变性，在横断后4天，嗅球中没有HRP反应产物。到第35天时，向中枢生长的嗅轴突已到达嗅球。轴突形成的小球比未手术对照嗅球中的小球小，并且它们并不总是局限于嗅球的小球层。一些动物显示出强大的纤维生长，轴突束穿透嗅球的不同层并沿其路径形成异位小球。二级嗅球神经元含有麦胚凝集素HRP反应产物，表明发生了跨神经元运输。电子显微镜证实了嗅觉轴突与二级嗅球神经元之间的跨神经元运输。这些结果表明，仓鼠的嗅觉神经元恢复和重新连接能力在老年时仍然存在。
