Woolf C J, Shortland P, Coggeshall R E
Department of Anatomy and Developmental Biology, University College London.
Nature. 1992 Jan 2;355(6355):75-8. doi: 10.1038/355075a0.
The central terminals of primary afferent neurons are topographically highly ordered in the spinal cord. Peripheral receptor sensitivity is reflected by dorsal horn laminar location: low-threshold mechanoreceptors terminate in laminae III and IV (refs 2, 3) and high-threshold nociceptors in laminae I, II and V (refs 4,5). Unmyelinated C fibres, most of which are nociceptors, terminate predominantly in lamina II (refs 5, 7). There is therefore an anatomical framework for the transfer of specific inputs to localized subsets of dorsal horn neurons. This specificity must contribute to the relationship between a low-intensity stimulus and an innocuous sensation and a noxious stimulus and pain. We now show that after peripheral nerve injury the central terminals of axotomized myelinated afferents, including the large A beta fibres, sprout into lamina II. This structural reorganization in the adult central nervous system may contribute to the development of the pain mediated by A-fibres that can follow nerve lesions in humans.
初级传入神经元的中枢终末在脊髓中呈高度有序的拓扑分布。背角分层位置反映了外周感受器的敏感性：低阈值机械感受器终止于Ⅲ层和Ⅳ层（参考文献2、3），高阈值伤害感受器终止于Ⅰ层、Ⅱ层和Ⅴ层（参考文献4、5）。无髓鞘C纤维大多为伤害感受器，主要终止于Ⅱ层（参考文献5、7）。因此，存在一个将特定输入传递至背角神经元局部亚群的解剖学框架。这种特异性必定有助于低强度刺激与无害感觉以及有害刺激与疼痛之间的关系。我们现在表明，在周围神经损伤后，包括粗大的Aβ纤维在内的被切断轴突的有髓传入纤维的中枢终末会向Ⅱ层生长出芽。成年中枢神经系统中的这种结构重组可能有助于由A纤维介导的疼痛的发生，而这种疼痛在人类神经损伤后可能会出现。
