Sang Q, Young H M
Department of Anatomy and Cell Biology, University of Melbourne, Victoria, Australia.
Brain Res. 1998 Nov 2;809(2):253-68. doi: 10.1016/s0006-8993(98)00893-2.
Retrograde and anterograde tracing and immunohistochemical techniques were used to examine the origin of the extrinsic innervation, and the development of the vagal innervation to the mouse esophagus. Cholinergic nerve terminals were localised using an antiserum to the vesicular acetylcholine transporter and cholinergic cell bodies were localised using an antiserum to choline acetyltransferase. Cholinergic nerve terminals, which also contained calcitonin gene-related peptide, were present at the motor end plates in the external (striated) muscle of the esophagus. Following injection of Fast Blue into subdiaphragmatic or cervical levels of the esophagus, the only retrogradely-labelled cholinergic nerve cell bodies that also contained calcitonin gene-related peptide were found in the nucleus ambiguus. Neurons in the dorsal motor nucleus of the vagus, the nodose ganglia and dorsal root ganglia gave rise to a number of different types of nerve terminals within the myenteric plexus. Retrogradely-labelled neurons in the dorsal motor nucleus of vagus contained cholinergic markers only, nitric oxide synthase only or cholinergic markers plus nitric oxide synthase, retrogradely-labelled neurons in the dorsal root ganglia contained calcitonin gene-related peptide only, and a small number of retrogradely-labelled neurons in the nodose ganglia contained tyrosine hydroxylase. The development of the vagal innervation to the esophagus was examined following application of DiI to the vagus nerve of fixed mouse embryos. Anterogradely-labelled nerve fibres, which arose from both nodose ganglia and the medulla, were already present in the esophagus of embryonic day 12 (E12) mice. Some of the DiI-labelled vagal nerve fibres were present in among the smooth muscle cells of the external muscle layer prior to their transdifferentiation to striated muscle. We conclude that the neurons in the nucleus ambiguus that project to the esophagus differ from other extrinsic neurons in their chemistry as well as their targets within the esophagus. The development of the extrinsic innervation precedes the transdifferentiation of the external muscle to striated muscle, raising the possibility that, during development, smooth muscle of the esophagus is innervated transiently by vagal neurons.
采用逆行和顺行示踪及免疫组化技术，研究小鼠食管外源性神经支配的起源以及迷走神经支配的发育情况。使用抗囊泡乙酰胆碱转运体抗血清定位胆碱能神经末梢，使用抗胆碱乙酰转移酶抗血清定位胆碱能细胞体。食管外（横纹肌）肌运动终板处存在同时含有降钙素基因相关肽的胆碱能神经末梢。将快蓝注入食管的膈下或颈部水平后，仅在疑核中发现了同时含有降钙素基因相关肽的逆行标记胆碱能神经细胞体。迷走神经背运动核、结状神经节和背根神经节中的神经元在肌间神经丛内产生多种不同类型的神经末梢。迷走神经背运动核中的逆行标记神经元仅含有胆碱能标记物、仅含有一氧化氮合酶或同时含有胆碱能标记物和一氧化氮合酶，背根神经节中的逆行标记神经元仅含有降钙素基因相关肽，结状神经节中的少量逆行标记神经元含有酪氨酸羟化酶。在固定的小鼠胚胎迷走神经上应用碘化丙啶后，研究了食管迷走神经支配的发育情况。来自结状神经节和延髓的顺行标记神经纤维在胚胎第12天（E12）小鼠的食管中已经存在。一些碘化丙啶标记的迷走神经纤维在其向横纹肌转分化之前就存在于外肌层的平滑肌细胞之间。我们得出结论，投射到食管的疑核中的神经元在化学性质以及食管内的靶点方面与其他外源性神经元不同。外源性神经支配的发育先于外肌向横纹肌的转分化，这增加了在发育过程中食管平滑肌由迷走神经元短暂支配的可能性。
