Effects of advancing age on the central response of rat facial neurons to axotomy: light microscope morphometry.
Effects of advancing age on the central response of rat facial neurons to axotomy: light microscope morphometry.
复制标题
年龄增长对大鼠面部神经元轴索切断术中枢反应的影响：光学显微镜形态测量。
DOI：
10.1002/ar.1092280212
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Vaughan,DW
中科院分区：
文献类型：
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作者：
Vaughan,DW
轴突切断后，外周轴突的再生需要更长的时间在老年人比年轻人。本研究比较了3个月龄和15个月龄雄性大鼠在挤压后28天（dpc）内面神经挤压损伤时面运动神经元的中枢反应。在30 μm脑干切片中测量了面神经核亚部内的神经元胞体、细胞核和核仁，面神经核亚部包含负责触须运动的细胞体。三个结构的大小变化的时间模式被解释为功能连接的重建，即，自愿触须活动的恢复，相对于年轻动物，老年动物延迟4天。体细胞肿胀和恢复模式无年龄相关差异，细胞核和核仁对4 dpc轴突切断术的反应也无年龄相关差异。两个年龄组动物的细胞核和核仁大小均增加，但在4 dpc后，老年动物的细胞核扩大延长，核仁增加与年轻动物相比不太稳健。最大的年龄差异出现在功能连接的重建中。在3月龄动物中，触须活动的恢复与细胞核和核仁大小的剧烈短暂增加相一致;在15月龄动物中，细胞核对功能恢复的反应很小，细胞核大小的增加相对较小。考虑到当达到目标时，来自外周的信号会引发中枢代谢变化，这项研究表明，前进的恶化效应可能不仅仅存在于神经元弹性的降低，而且可能存在于来自外周支持细胞、目标肌肉或接收这些信号的信号的缺陷。
Following axotomy, the regrowth of peripheral axons takes longer in older individuals than in young ones. The present study compares central responses of facial motor neurons to a crush injury of the facial nerve in 3‐month‐old and 15‐month‐old male rats sampled through 28 days post‐crush (dpc). Neuronal somata, nuclei, and nucleoli were measured in 30 μm brain stem sections within subdivisions of the facial nucleus that contain the cell bodies responsible for the movement of the vibrissae. The temporal patterns of change in the size of the three structures were interpreted with reference to the re‐establishment of functional connections, i.e., the return of voluntary vibrissae activity, which is delayed by 4 days in the older animals relative to the younger ones. There was no age‐related difference in the pattern of somal swelling and recovery, nor was there an age‐related difference in the response of nuclei and nucleoli to axotomy through 4 dpc. Both nuclei and nucleoli increased in size in animals of both age groups, but after 4 dpc in the older animals nuclear enlargement was prolonged and the nucleolar increases were less robust compared to the younger animals. The greatest age difference appeared with the re‐establishment of functional connections. In the 3‐month‐old animals, the resumption of whisker activity coincided with vigorous transient increases in the sizes of nuclei and nucleoli; in the 15‐month‐old animals, there was little nuclear response to functional recovery and a comparatively small increase in nuclear sizes. Given that signals from the periphery initiate central metabolic changes when the target is reached, this study suggests that the deteriorative effects of advancing may not simply reside in the neuron's decreased resiliency, but may reside in deficiencies in the signals derived from peripheral supporting cells, the target muscle, or in the reception of those signals.