Brouns Inge, Oztay Fusun, Pintelon Isabel, De Proost Ian, Lembrechts Robrecht, Timmermans Jean-Pierre, Adriaensen Dirk
Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
Histochem Cell Biol. 2009 Jan;131(1):55-74. doi: 10.1007/s00418-008-0495-7. Epub 2008 Sep 2.
As best characterized for rats, it is clear that pulmonary neuroepithelial bodies (NEBs) are contacted by a plethora of nerve fiber populations, suggesting that they represent an extensive group of multifunctional intraepithelial airway receptors. Because of the importance of genetically modified mice for functional studies, and the current lack of data, the main aim of the present study was to achieve a detailed analysis of the origin and neurochemical properties of nerve terminals associated with NEBs in mouse lungs. Antibodies against known selective markers for sensory and motor nerve terminals in rat lungs were used on lungs from control and vagotomized mice of two different strains, i.e., Swiss and C57-Bl6. NEB cells were visualized by antibodies against either the general neuroendocrine marker protein gene-product 9.5 (PGP9.5) or calcitonin gene-related peptide (CGRP). Thorough immunohistochemical examination of NEB cells showed that some of these NEB cells also exhibit calbindin D-28 k (CB) and vesicular acetylcholine transporter (VAChT) immunoreactivity (IR). Mouse pulmonary NEBs were found to receive intraepithelial nerve terminals of at least two different populations of myelinated vagal afferents: (1) Immunoreactive (ir) for vesicular glutamate transporters (VGLUTs) and CB; (2) expressing P2X(2) and P2X(3) ATP receptors. CGRP IR was seen in varicose vagal nerve fibers and in delicate non-vagal fibers, both in close proximity to NEBs. VAChT immunostaining showed very weak IR in the NEB-related intraepithelial vagal sensory nerve terminals. nNOS- or VIP-ir nerve terminals could be observed at the base of pulmonary NEBs. While a single NEB can be contacted by multiple nerve fiber populations, it was clear that none of the so far characterized nerve fiber populations contacts all pulmonary NEBs. The present study revealed that mouse lungs harbor several populations of nerve terminals that may selectively contact NEBs. Although at present the physiological significance of the innervation pattern of NEBs remains enigmatic, it is likely that NEBs are receptor-effector end-organs that may host complex and/or multiple functional properties in normal airways. The neurochemical information on the innervation of NEBs in mouse lungs gathered in the present study will be essential for the interpretation of upcoming functional data and for the study of transgenic mice.
就大鼠的情况而言，很明显肺神经上皮小体（NEBs）与大量神经纤维群相接触，这表明它们代表了一组广泛的多功能上皮内气道受体。由于基因改造小鼠对功能研究的重要性，且目前缺乏相关数据，本研究的主要目的是详细分析小鼠肺中与NEBs相关的神经末梢的起源和神经化学特性。针对大鼠肺中感觉和运动神经末梢已知选择性标记物的抗体，被用于两种不同品系（即瑞士小鼠和C57-Bl6小鼠）的对照小鼠和迷走神经切断小鼠的肺组织。通过针对一般神经内分泌标记物蛋白基因产物9.5（PGP9.5）或降钙素基因相关肽（CGRP）的抗体来观察NEB细胞。对NEB细胞进行全面的免疫组织化学检查发现，其中一些NEB细胞还表现出钙结合蛋白D-28k（CB）和囊泡乙酰胆碱转运体（VAChT）免疫反应性（IR）。发现小鼠肺NEBs接受至少两种不同的有髓迷走传入神经纤维群的上皮内神经末梢：（1）对囊泡谷氨酸转运体（VGLUTs）和CB呈免疫反应性（ir）；（2）表达P2X(2)和P2X(3)ATP受体。在与NEBs紧邻的曲张迷走神经纤维和纤细的非迷走神经纤维中可见CGRP免疫反应性。VAChT免疫染色显示在与NEB相关的上皮内迷走感觉神经末梢中免疫反应性非常弱。在肺NEBs的基部可观察到nNOS或VIP免疫反应性神经末梢。虽然单个NEB可与多个神经纤维群接触，但很明显，迄今为止所鉴定的神经纤维群中没有一个与所有肺NEBs接触。本研究表明，小鼠肺中存在几种可能选择性接触NEBs的神经末梢群。虽然目前NEBs的神经支配模式的生理意义仍然不明，但NEBs很可能是受体效应终末器官，在正常气道中可能具有复杂和/或多种功能特性。本研究收集的关于小鼠肺中NEBs神经支配的神经化学信息，对于解释即将获得的功能数据以及研究转基因小鼠至关重要。
