Hsieh J H, Chen R F, Wu J J, Yen C T, Chai C Y
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
J Auton Nerv Syst. 1998 May 28;70(1-2):38-50. doi: 10.1016/s0165-1838(98)00027-7.
The origin of medullary cells that form the cardiac vagal branch and the vagal branches in the lower thorax innervating the gastrointestinal (GI) tract was studied using horseradish peroxidase (HRP), a retrograde transport tracer in the cat. The distributions of parasympathetic postganglionic neurons of the heart were studied with acetylcholinesterase histochemistry. Intracardiac ganglionic neurons were found mainly in the connective tissue surrounding the base of the pulmonary arteries and in an area in and dorsal to the interatrial septum. Following injection of HRP into the subepicardum where most of the cardiac postganglionic neurons reside, 91% of the labelled neurons were found bilaterally distributed in the nucleus ambiguus (NA). A small population of labelled neurons was found in the dorsal motor nucleus of the vagus (DMV) and an intermediate zone (IZ) between the two nuclei. When HRP was injected into the left or right cardiopulmonary vagus branch, labelled neurons were found exclusively in the ipsilateral NA, DMV and IZ with a predominance in the NA. In the thorax, after they course around the heart, the left and right thoracic vagus nerves divides into a left and a right branch, respectively. The left branch of the left thoracic vagus joins the left branch of the right thoracic vagus to form the anterior vagus nerve at 3 cm above the diaphragm. The right branch of the right thoracic vagus nerve joins the right branch of the left thoracic vagus to form the posterior vagus nerve. After application of HRP into the right or the left branch of the left thoracic vagus, HRP labelled cells were found in the left DMV. Similarly, after application of HRP into the left or the right branch of the right thoracic vagus, labelled cells were found in the right DMV. On the other hand, when HRP was injected into the anterior vagus, labelled neurons were found bilaterally in the DMV. This suggests that all rostral branches of the thoracic vagus have their origin in the ipsilateral DMV, and intermixing occurs only at the caudal level near the diaphragm. Findings of the present experiments suggest that parasympathetic preganglionic neurons innervating the GI tract are located exclusively in the DMV while those of the heart are located mainly in the NA. Within the DMV, GI vagal neurons were found medially from the level 0-2.5 mm rostral to the obex. In contrast, cardiac vagal neurons were found in the lateral edge of the DMV at the level 0-1 mm rostral to the obex.
利用辣根过氧化物酶（HRP）这一逆行运输示踪剂，在猫身上研究了形成心脏迷走神经分支以及支配胃肠道（GI）的下胸部迷走神经分支的髓质细胞起源。用乙酰胆碱酯酶组织化学法研究了心脏副交感神经节后神经元的分布。心内神经节神经元主要见于肺动脉基部周围的结缔组织以及房间隔内和背侧的一个区域。将HRP注入大多数心脏节后神经元所在的心外膜下后，发现91%的标记神经元双侧分布于疑核（NA）。在迷走神经背运动核（DMV）以及两核之间的中间带（IZ）发现少量标记神经元。当将HRP注入左或右心肺迷走神经分支时，标记神经元仅见于同侧的NA、DMV和IZ，其中以NA为主。在胸部，左右胸迷走神经绕过心脏后分别分为左、右分支。左胸迷走神经的左支与右胸迷走神经的左支在膈上3 cm处汇合形成前迷走神经。右胸迷走神经的右支与左胸迷走神经的右支汇合形成后迷走神经。将HRP注入左胸迷走神经的右或左分支后，在左侧DMV发现HRP标记细胞。同样，将HRP注入右胸迷走神经的左或右分支后，在右侧DMV发现标记细胞。另一方面，当将HRP注入前迷走神经时，在双侧DMV发现标记神经元。这表明胸段迷走神经的所有头侧分支均起源于同侧DMV，仅在膈附近的尾侧水平发生混合。本实验结果表明，支配胃肠道的副交感神经节前神经元仅位于DMV，而支配心脏的副交感神经节前神经元主要位于NA。在DMV内，胃肠道迷走神经元见于闩前方0 - 2.5 mm水平的内侧。相反，心脏迷走神经元见于闩前方0 - 1 mm水平的DMV外侧缘。
