Differing Neurophysiologic Mechanosensory Input From Glabrous and Hairy Skin in Juvenile Rats
Differing Neurophysiologic Mechanosensory Input From Glabrous and Hairy Skin in Juvenile Rats
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DOI：
10.1152/jn.00415.2010
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发表时间：
2010-12-01
影响因子：
2.5
通讯作者：
Ririe, Douglas G.
中科院分区：
文献类型：
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作者：
Boada, M. Danilo;Houle, Timothy T.;Ririe, Douglas G.
博阿达MD，胡勒TT，Eisenach JC，Ririe DG。幼年大鼠无毛和有毛皮肤的不同神经生理学机械感觉输入。神经生理学杂志104：3568-3575,2010。2010年10月6日首次出版；DOI：10.1152/jn.00415.2010。皮肤中的感官传入编码并传达热和机械条件，包括那些威胁组织损伤的条件。一小部分皮肤，即远端肢体的无毛皮肤，专门用于探索环境的细节。除了神经密度增加外，对于年轻动物无毛皮肤的机械感觉传入特性，人们知之甚少，这解释了快速采样物理结构(包括那些威胁受伤的结构)时的精致精度和高对比度。为了评估这一点，我们从幼年大鼠的腰背根节和胸背根节中获得了115个机械敏感型传入神经元的完整细胞内记录。无毛皮肤有两个独特的特征：与有毛皮肤相比，作为高阈值机械伤害性感受器的快传导传入与慢传导传入的比例高出三倍；与有毛皮肤相比，快传导伤害性感受器的传导速度快两倍。此外，对于每种纤维类型，无毛皮和有毛皮之间的机械阈值也存在差异。这些差异反映并帮助解释了专门探索物理环境的皮肤的快速反应。此外，这些结果强调了在不知道初级传入神经所支配的皮肤类型的情况下，仅使用被动电学特性和传导速度来表征初级传入神经的潜在局限性。
Boada MD, Houle TT, Eisenach JC, Ririe DG. Differing neurophysiologic mechanosensory input from glabrous and hairy skin in juvenile rats. J Neurophysiol 104: 3568-3575, 2010. First published October 6, 2010; doi:10.1152/jn.00415.2010. Sensory afferents in skin encode and convey thermal and mechanical conditions, including those that threaten tissue damage. A small proportion of skin, the glabrous skin of the distal extremities, is specialized to explore the environment in fine detail. Aside from increased innervation density, little is known regarding properties of mechanosensory afferents to glabrous skin in younger animals that explain the exquisite precision and high contrast in rapidly sampling physical structures, including those that threaten injury. To assess this, we obtained intact neuronal intracellular recordings in vivo from 115 mechanosensitive afferent neurons from lumbar and thoracic dorsal root ganglia in juvenile rats. Two characteristics were unique to glabrous skin: a threefold higher proportion of fast-conducting to slow-conducting afferents that were high-threshold mechanosensitive nociceptors compared with hairy skin and a twofold faster conduction velocity of fast-conducting nociceptors compared with hairy skin. Additionally differences were found in mechanical thresholds between glabrous skin and hairy skin for each fiber type. These differences reflect and help explain the rapid response of skin specialized to explore the physical environment. Additionally, these results highlight potential limitations of using passive electrical properties and conduction velocity alone to characterize primary afferents without knowledge of the skin type they innervated.