The effects of age on enzyme activities in the rat facial nucleus following axotomy: acetylcholinesterase and cytochrome oxidase.
The effects of age on enzyme activities in the rat facial nucleus following axotomy: acetylcholinesterase and cytochrome oxidase.
复制标题
年龄对轴索切除术后大鼠面核酶活性的影响：乙酰胆碱酯酶和细胞色素氧化酶。
DOI：
10.1016/0014-4886(90)90077-6
复制
发表时间：
1990
影响因子：
5.3
通讯作者：
Vaughan,DW
中科院分区：
文献类型：
--
作者：
Vaughan,DW
随着年龄的增长，运动神经元在面神经被挤压后再生轴突的能力会受到影响。在大鼠中，3个月大的动物在受伤后需要14天才能恢复正常的胡须活动，而15个月大的动物至少需要19天。本研究探讨面运动神经元对轴突切断的中枢酶反应。在术后第1天至第8周期间，对脑干的交替冰冻切片进行组织化学反应，以显示乙酰胆碱酯酶（AChE）或细胞色素氧化酶（考克斯）的活性，并使用计算机图像分析密度测定法对反应进行定量。AChE活性分别在核周细胞质和神经元中进行评价，而考克斯在面神经核中作为一个整体进行测定。与轴突生长的起始相一致，这些酶的活性在神经元中降低。对于乙酰胆碱酯酶，老年动物的下降幅度更大;对于考克斯，两个年龄组的下降幅度相等。至于核周AChE和神经元AChE，在两个位置的恢复模式是不同的。在perikarya AChE活性开始恢复4天后，在两个年龄组，然而，AChE活性的神经元仍然下降，直到功能恢复后的晶须活动，当它恢复迅速，在3个月大的动物，但更逐渐在15个月大的动物。在这两个年龄组中，考克斯活性逐渐减少，以响应轴突切断术。在3个月大的动物中，它在胡须活动恢复后迅速恢复，而在15个月大的动物中，考克斯活动在压碎后28天内保持在降低的水平，然后开始逐渐恢复。研究表明，年龄差异在功能连接重建后最为明显。这种与年龄相关的缺陷可能与来自神经再支配目标的逆向传输信号或老年神经元对此类信号作出反应的能力的缺陷有关。
Advancing age affects the ability of motor neurons to regrow axons after the facial nerve is crushed. In rats, it requires 14 days after injury for 3-month-old animals to resume normal whisker activity, compared to at least 19 days in 15-month-old animals. The present study examines central enzymatic responses of facial motor neurons to axotomy. During the postoperative period from 1 day through 8 weeks, alternate frozen sections of brain stem are histochemically reacted to demonstrate activities of acetylcholinesterase (AChE) or cytochrome oxidase (COX) and the reactions are quantified using computerized image analyzing densitometry. AChE activity is evaluated separately in perikaryal cytoplasm and neuropil, while COX is assayed in the facial nucleus as a whole. Coincident with the initiation of axon outgrowth the activities of these enzymes decrease in the neurons. For AChE the decrease is greater in the older animals; for COX the decrease is equivalent in both age groups. With regard to the perikaryal AChE and the neuropil AChE, the recovery patterns are different in the two locations. In the perikarya AChE activity begins to recover after 4 days in both age groups; however, AChE activity in the neuropil remains decreased until after functional recovery of whisker activity, when it recovers rapidly in the 3-month-old animals, but more gradually in the 15-month-old animals. In both age groups, COX activity gradually decreases in response to axotomy. In the 3-month-old animals it recovers rapidly following return of whisker activity, while in the 15-month animals COX activity is maintained at the decreased level through 28 days postcrush, before it begins its gradual recovery. The study demonstrates that age differences are most apparent after the reestablishment of functional connections. This age-related deficiency may be related to deficiencies in retrogradely transported signals arising from the reinnervated target or in the older neurons's ability to respond to such signals.