Physiological properties of primary sensory neurons appropriately and inappropriately innervating skin in the adult rat.
Physiological properties of primary sensory neurons appropriately and inappropriately innervating skin in the adult rat.
复制标题
成年大鼠初级感觉神经元适当和不适当支配皮肤的生理特性。
DOI：
10.1152/jn.1991.66.4.1205
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发表时间：
1991
影响因子：
2.5
通讯作者：
Stephen B. McMahon
中科院分区：
文献类型：
--
作者：
Gary R. Lewin;Stephen B. McMahon
1.本文对支配大鼠后肢皮肤的感觉神经元的生理学进行了研究，分三组动物：1）正常动物，2）腓肠神经（Sn）再生到原来皮肤靶点的动物，3）腓肠神经再生到原来皮肤靶点的动物。和3）腓肠肌神经（Gn）之前已被切割并与切口Sn的远端残端交叉吻合，以便其轴突再生到外来目标（皮肤）。2.单单位录音，从222传入正常，完整的动物。它们的传导速度为0.5-53.1 m/s。传导速度分布在约37.5、2.5和1.25 m/s处具有明显的峰值，推测对应于A α β、A δ和C纤维群。82%的有髓神经纤维具有低阈值机械敏感感受野，而16%的有髓神经纤维具有高阈值机械敏感感受野，只有2%的有髓神经纤维没有感受野。绝大多数的低阈值机械敏感感受野（87%）是快速适应毛囊传入。3.在再生Sn的动物中，记录到308个传入，传导速度为0.4-58.8 m/s。然而，平均传导速度低于对照组动物（P <0.05），有髓纤维只有一个峰值，为27.5 m/s。86%的有髓纤维是低阈值机械敏感传入，8.5%是高阈值机械感受器（HTMR），5.5%似乎没有感受野。较少的低阈值机械感受器（LTMR;与对照组相比）被毛发运动激活（63 vs. 87%）。其余的大部分似乎是场受体（因此在这里比在正常动物中更常见）。4.在Gn再生到皮肤的动物中，记录了430个传入。它们的传导速度范围为0.6至71.4 m/s，并且在有髓鞘传导速度直方图中再次仅一个峰值明显，约为17.5 m/s。在有髓神经纤维中，79%的皮肤有低阈值机械敏感感受野，10%的皮肤有高阈值机械敏感感受野。剩下的11%显然没有感受野（cf. 5.5%（在再生Sn中）。与正常或再生的腓肠神经传入相比，皮肤中只有58%的低阈值腓肠肌传入迅速适应。在42%的缓慢适应传入神经中，令人惊讶的是，许多人对毛发运动做出了反应。因此，一些腓肠肌传入似乎保留了肌肉传入的适应特性。同样令人惊讶的是，考虑到Gn含有比Sn更少的纤维，感受野面积与再生或正常的腓肠纤维没有显著差异。（400字处截断摘要）
1. We have studied the physiology of sensory neurons innervating skin of the rat hindlimb, in three groups of animals: 1) normal animals; 2) animals in which the sural nerve (Sn) had regenerated to its original cutaneous target; and 3) animals in which the gastrocnemius muscle nerve (Gn) had previously been cut and cross anastomosed with the distal stump of the cut Sn so that its axons regenerated to a foreign target, skin. 2. Single-unit recordings were made from 222 afferents in normal, intact animals. They had conduction velocities of 0.5-53.1 m/s. The conduction velocity distribution had distinct peaks at approximately 37.5, 2.5, and 1.25 m/s, presumably corresponding to A alpha beta-, A delta-, and C-fiber populations. Eighty-two percent of the characterized myelinated fibers had low-threshold mechanosensitive receptive fields, whereas 16% were high threshold, and only 2% appeared to have no receptive field. The very large majority of low-threshold mechanosensitive receptive fields (87%) were rapidly adapting hair follicle afferents. 3. In animals with regenerated Sn, 308 afferents were recorded with conduction velocities of 0.4-58.8 m/s. However, the mean conduction velocity was lower than in control animals (P less than 0.05), and only one peak, at 27.5 m/s, was apparent for myelinated fibers. Eighty-six percent of myelinated fibers were low-threshold mechanosensitive afferents, 8.5% were high-threshold mechanoreceptors (HTMRs), and 5.5% appeared to have no receptive fields. Fewer low-threshold mechanoreceptors (LTMRs; compared with controls) were activated by hair movement (63 vs. 87%). Most of the remainder appeared to be field receptors (which were therefore more commonly observed here than in normal animals). 4. In animals in which the Gn had regenerated to skin, 430 afferents were recorded. These had conduction velocities ranging from 0.6 to 71.4 m/s, and again only one peak was apparent in the myelinated conduction velocity histogram, at approximately 17.5 m/s. Of the myelinated fibers, 79% had low-threshold mechanosensitive receptive fields in skin and 10% high-threshold mechanosensitive receptive fields. The remaining 11% apparently had no receptive field (cf. 5.5% in regenerated Sn). In contrast to normal or regrown sural afferents, only 58% of low-threshold gastrocnemius afferents in skin were rapidly adapting. Of the 42% slowly adapting afferents, many surprisingly responded to hair movement. Thus some gastrocnemius afferents seemed to have retained the adaptation properties characteristic of muscle afferents. Also surprisingly, given that the Gn contains fewer fibers than the Sn, receptive-field areas were not significantly different from regrown or normal sural fibers.(ABSTRACT TRUNCATED AT 400 WORDS)