Berthoud H R, Jedrzejewska A, Powley T L
Laboratory of Regulatory Psychobiology, Purdue University, West Lafayette, Indiana 47907.
J Comp Neurol. 1990 Nov 1;301(1):65-79. doi: 10.1002/cne.903010107.
The vagal innervation of the different layers of the rat gastrointestinal wall was identified with the fluorescent carbocyanine dye Dil, injected into the dorsal motor nucleus of the vagus (dmnX). Multiple, bilateral injections were used to label all dmnX preganglionic motoneurons, and as a consequence, most of the vagal primary afferents that terminate in the adjacent nucleus of the solitary tract (nts) were also retrogradely and transganglionically labeled. With Fluorogold used to label the enteric nervous system completely and specifically, the Dil-labeled vagal profiles could be visualized and quantified in their anatomical relation to the neurons of the myenteric and submucous ganglia. In the myenteric plexus, vagal fibers and terminals were found throughout the gastrointestinal tract as far caudal as the descending colon, but there was a general decreasing proximodistal gradient in the density of vagal innervation. All parts of the gastric myenteric plexus (fundus, corpus, antrum), as well as the proximal duodenum, were extremely densely innervated, with vagal fibers and terminals in virtually every ganglion and connective. Further caudally, both the percentage of innervated myenteric ganglia and the average density of label within the ganglia rapidly decreased, with the exception of the cecum and proximal colon, where up to 65% of the ganglia were innervated. In the gastric and duodenal submucosa very few and in the mucosa no vagal fibers and terminals were found. With both normal epifluorescence and laser scanning confocal microscopy, highly varicose or beaded terminal structures of various size and geometry could be identified. The Dil injections, which impregnated the dmnX as well as the adjacent nts, resulted in retrograde and anterograde labeling of all the previously reported forebrain connections with the dorsal vagal complex. We conclude that the myenteric plexus is the primary target of vagal innervation throughout the gastrointestinal tract, and that its innervation is more complete than previously assumed. In contrast, vagal afferent (and efferent) innervation of mucosa and submucosa seems conspicuously sparse or absent. Furthermore, the use of more focal injections of Dil offers the prospect to simultaneously identify specific subsets of vagal preganglionics and their central nervous inputs.
将荧光花菁染料Dil注入大鼠迷走神经背运动核（dmnX），以此确定大鼠胃肠道壁不同层次的迷走神经支配。采用多次双侧注射来标记所有dmnX节前运动神经元，结果，大多数终止于相邻孤束核（nts）的迷走神经初级传入纤维也被逆行和顺行跨节标记。用荧光金完全且特异性地标记肠神经系统后，可观察并量化Dil标记的迷走神经轮廓与肌间神经节和黏膜下神经节神经元的解剖关系。在肌间神经丛中，迷走神经纤维和终末在整个胃肠道均可发现，最远可达降结肠，但迷走神经支配密度存在从近端到远端总体递减的梯度。胃肌间神经丛的所有部分（胃底、胃体、胃窦）以及十二指肠近端均有极其密集的神经支配，几乎每个神经节和结缔组织中都有迷走神经纤维和终末。再向尾端，有神经支配的肌间神经节百分比以及神经节内的平均标记密度迅速降低，但盲肠和近端结肠除外，此处高达65%的神经节有神经支配。在胃和十二指肠黏膜下层发现的迷走神经纤维和终末极少，而在黏膜层未发现。通过普通落射荧光显微镜和激光扫描共聚焦显微镜，均可识别出各种大小和形态的高度曲张或串珠状终末结构。注入Dil使dmnX以及相邻的nts均被浸染，导致所有先前报道的与迷走神经背侧复合体的前脑连接均被逆行和顺行标记。我们得出结论，肌间神经丛是整个胃肠道迷走神经支配的主要靶点，并且其神经支配比先前设想的更为完整。相比之下，迷走神经对黏膜和黏膜下层的传入（和传出）神经支配似乎明显稀疏或缺失。此外，采用更局部的Dil注射有望同时识别迷走神经节前神经元的特定亚群及其中枢神经输入。
