Mosconi T M, Rice F L
Department of Anatomy and Cell Biology, UCLA Center for Health Sciences 90024.
J Comp Neurol. 1993 Jul 15;333(3):309-25. doi: 10.1002/cne.903330302.
The mystacial pad of the ferret has an elaborate sensory innervation provided by three types of terminal nerves that arise from the infraorbital branch of the trigeminal nerve. Deep and superficial vibrissal nerves innervate nearly exclusive targets in the large follicle-sinus complexes (F-SCs) at the base of each tactile vibrissa. Dermal plexus nerves innervate the fur between the vibrissae. Each type of nerve provides a similar variety of sensory endings, albeit to different targets. In this study, Winkelmann and Sevier-Munger reduced silver techniques revealed that most of the endings differentiate postnatally in an overlapping sequence like that observed previously in the rat. Afferents from the deep vibrissal nerves begin to differentiate first, followed successively by those from superficial vibrissal nerves and the dermal plexus. Within each type of nerve, Merkel endings begin to differentiate first, followed successively by lanceolate endings and circumferential endings. In the ferret, the differentiation of the intervibrissal fur and its innervation is slightly delayed but substantially overlaps the development of the vibrissal innervation, whereas in the rat it occurs almost entirely later. There was no evidence of a transient exuberant or misplaced innervation or other secondary remodeling. Differentiating afferents and endings are located only in the sites normally seen in the adult, suggesting a high degree of afferent-target specificity. In the ferret, innervation is virtually lacking in one target--the inner conical body of the F-SCs, which is densely innervated in the rat. This lack was due to a failure of innervation to develop rather than to a secondary elimination of a transient innervation.
雪貂的触须垫具有复杂的感觉神经支配，由源自三叉神经眶下支的三种终末神经提供。深、浅触须神经几乎专门支配每个触觉触须基部的大型毛囊 - 窦复合体（F - SCs）中的目标。真皮丛神经支配触须之间的毛发。每种神经都提供了类似种类的感觉末梢，尽管针对不同的目标。在本研究中，Winkelmann和Sevier - Munger还原银染色技术显示，大多数末梢在出生后以重叠的顺序分化，就像之前在大鼠中观察到的那样。来自深触须神经的传入神经首先开始分化，随后依次是来自浅触须神经和真皮丛的传入神经。在每种神经类型中，默克尔末梢首先开始分化，随后依次是柳叶状末梢和环形末梢。在雪貂中，触须间毛发及其神经支配的分化略有延迟，但与触须神经支配的发育有很大重叠，而在大鼠中，它几乎完全在后期发生。没有证据表明存在短暂的过度或错位神经支配或其他二次重塑。正在分化的传入神经和末梢仅位于成体中正常可见的部位，表明传入神经 - 目标具有高度特异性。在雪貂中，一个目标——F - SCs的内锥体几乎没有神经支配，而在大鼠中该部位神经支配密集。这种缺乏是由于神经支配未能发育，而不是由于短暂神经支配的二次消除。
