Saltis J, Rush R A
Department of Physiology, Flinders University, Adelaide, South Australia.
Int J Dev Neurosci. 1995 Oct;13(6):577-84. doi: 10.1016/0736-5748(95)93595-g.
Wing bud removal in chick embryos has been shown to affect the generation of sympathetic neurons prior to the normal period of limb innervation [Saltis and Rush (1995) J. auton. nerv. Sys., 51, 117-127.]. Pyknotic activity occurred earlier within the peripherally deprived ganglion, suggesting that a precocious cell death of dividing sympathoblasts led to the reduced neuronal population. We have now sought to test whether the effect of limb bud extirpation can be overcome by the administration of nerve growth factor (NGF). Specifically, the peripherally deprived ganglion has been examined for mitotic activity and total neuronal numbers. In brachial ganglia from the operated side, neuron numbers decreased by 67% by embryonic day (E) 13, but by only 28% when NGF was administered from E9. Ganglia on the unoperated side were unaffected by the NGF treatment. In contrast, in embryos receiving NGF from E5 to E9, neuron numbers in the ganglia increased by more than 100%, on both the intact and operated side. This increase was accompanied by a greater proportion of 3H-thymidine-labelled neurons. We therefore conclude that NGF, in addition to its previously described role of preventing naturally occurring neuron death, can also affect the generation of sympathetic neurons. This ability of NGF to affect gangliogenesis is most likely achieved by increasing the survival of dividing neuroblasts, although a direct effect on mitosis has not been excluded.
在鸡胚中，去除翅芽已被证明会在肢体正常神经支配期之前影响交感神经元的生成[萨尔蒂斯和拉什（1995年）《自主神经系统杂志》，第51卷，第117 - 127页]。在周围神经被剥夺的神经节内，固缩活动出现得更早，这表明正在分裂的成神经细胞过早死亡导致神经元数量减少。我们现在试图测试给予神经生长因子（NGF）是否能克服肢体芽切除的影响。具体而言，已对周围神经被剥夺的神经节进行有丝分裂活性和神经元总数的检测。在手术侧的臂神经节中，到胚胎第13天（E13）时，神经元数量减少了67%，但从E9开始给予NGF时，仅减少了28%。未手术侧的神经节不受NGF治疗的影响。相反，在从E5到E9接受NGF的胚胎中，完整侧和手术侧神经节中的神经元数量均增加了100%以上。这种增加伴随着更高比例的3H - 胸腺嘧啶核苷标记神经元。因此，我们得出结论，NGF除了其先前描述的预防自然发生的神经元死亡的作用外，还能影响交感神经元的生成。NGF影响神经节形成的这种能力很可能是通过增加正在分裂的成神经细胞的存活率实现的，尽管尚未排除对有丝分裂的直接影响。
