| Summary: | 碩士 === 國立臺灣大學 === 解剖學暨細胞生物學研究所 === 91 === 英文摘要
We studied the effect of distal axonal injury, T10 tractotomy, on rat rubrospinal neurons. Nissl-stained tissue showed that there was no neuronal loss at least at 8 weeks following axotomy. Their cell bodies sizes were slightly increased 4-day-post-lesion and then reduced to about 80-85% of those of control cells by 8-week-post-lesion. The expressions of the AMPA receptor subunits GluR2/3, NMDA receptor subunit NR1, inhibitory GABA receptor subunit GABAAα, and the neuromodulatory serotonergic receptor 5-HT1A and 5-HT1B were not altered following distal axonal injury. The expression of nNOS was not changed either. In short, unlike C2 or brainstem axonal injuries, T10 axotomy triggered no change of the nNOS and postsynaptic receptor expressions in rubrospinal neurons. The extent of the up-regulation of nNOS and the alterations of postsynaptic receptor expressions following C2 and brainstem axotomies were accompanied by different amount of cell loss. This suggests that closeness of the axonal injury to neuronal cell bodies determined how they react. Although both C2 and T10 axotomies removed the spinal targets of lumbar-projection rubrospinal neurons, the former however removed longer segments of their spinal axons. Differences in the responses between axotomies at these two locations suggest that the amount of cytoplasm removed also determines how these neurons respond to axonal injury.
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