Reduction of the naturally occurring motor neuron loss by enlargement of the periphery
Reduction of the naturally occurring motor neuron loss by enlargement of the periphery
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通过扩大外周减少自然发生的运动神经元损失
DOI：
10.1002/cne.901700304
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发表时间：
1976
影响因子：
2.5
通讯作者：
V. Hamburger
中科院分区：
文献类型：
--
作者：
M. Hollyday;V. Hamburger
通过植入多余腿扩大外周后的运动增生不是由于增殖的“远程控制”，如6天鸡胚中的运动神经元计数所示。我们已经测试了另一种假设，即我们正在处理自然发生的细胞死亡的减少。在正常发育过程中，腰椎外侧运动柱（l.m.c.）发生运动神经元变性，导致至少40%的细胞损失，这发生在六天半到九天半之间。在移植多余腿后，选择的进行有力运动的病例显示实验侧和对侧（对照）之间的数值差异为+11.0%至+27.5%。移植物由不同组合的胸和吻侧腰神经支配。我们解释我们的数据在运动神经元的生存，通常会失败的竞争在外围，但这是持续扩大的外围领域。我们的数据不允许在两种选择之间做出决定：竞争突触位点或营养剂。存活的运动神经元不仅限于运动柱的吻侧节段，而且在大多数情况下沿着其整个吻尾侧范围分布，这意味着所有l.m.c.轴突“增生”一词不再适用于所考虑的现象，应改为“死亡减少”。
Motor hyperplasia following the enlargement of the periphery by implantation of a supernumerary leg is not due to “remote control” of proliferation, as shown by motor neuron counts in 6‐day chick embryos. We have tested the alternative hypothesis that we are dealing with reduction of the naturally occurring cell death. In normal development, the lumbar lateral motor column (l.m.c.) undergoes motor neuron degeneration resulting in a cell loss of at least 40%, which occurs between six and one‐half and nine and one‐half days. Following transplantation of supernumerary legs, cases selected for vigorous motility showed a numerical difference between experimental and contralateral (control) sides amounting to +11.0% to +27.5%. The transplants were innervated by varying combinations of thoracic and rostral lumbar nerves. We interpret our data in terms of survival of motor neurons which normally would have failed in a competition at the periphery but which were sustained by the enlarged peripheral fields. Our data do not permit a decision between the two alternatives: competition for synaptic sites or for a trophic agent. The surviving motor neurons are not limited to the rostral segments of the motor column but in most instances distributed along its entire rostro‐caudal extent, implying a redistribution of all l.m.c. axons. The term “hyperplasia” is no longer appropriate for the phenomenon under consideration and should be replaced by the term “hypothanasia.”