Nishi R
Department of Neurobiology, Harvard Medical School, Boston, Massachusetts.
J Neurosci Res. 1988 Oct-Dec;21(2-4):307-14. doi: 10.1002/jnr.490210223.
Using a new technique for organ explants that facilitates the visualization of developing epithelia, we tested the abilities of salivary gland and lung rudiments to support de novo axonal outgrowth from the embryonic submandibular ganglion. We confirmed that salivary gland epithelia, but not lung epithelia, are able to support axonal outgrowth. This neurite outgrowth is also supported by salivary gland epithelia that have been lightly fixed with paraformaldehyde. When given a choice of both salivary gland and lung epithelia as a substrate for axonal outgrowth, the submandibular ganglion neurons showed an absolute preference for the salivary gland. Immunohistochemical localization of laminin was performed on whole mounts of developing epithelia after growing neurites were localized with a histochemical stain for esterase. Areas of lung epithelium devoid of any neurite outgrowth contained substantial immunoreactivity for laminin. In addition, Western blot analyses of extracts of embryonic lung and salivary gland indicate that the same amount of laminin or more is present on a per protein basis in the lung as in the salivary gland. An antiserum directed against laminin and a monoclonal antibody that blocks axonal regeneration on basal laminae in vitro (INO) were unable to block the outgrowth of axons over fixed epithelia. This suggests that molecules other than laminin are responsible for the preferential growth of axons over the salivary gland epithelia.
我们使用一种新的器官外植体技术来促进发育中上皮细胞的可视化，测试了唾液腺和肺原基支持胚胎下颌下神经节从头生长轴突的能力。我们证实唾液腺上皮而非肺上皮能够支持轴突生长。这种神经突生长也得到了用多聚甲醛轻度固定的唾液腺上皮的支持。当同时提供唾液腺和肺上皮作为轴突生长的底物供选择时，下颌下神经节神经元对唾液腺表现出绝对偏好。在用酯酶组织化学染色定位生长的神经突后，对发育中上皮的整装标本进行层粘连蛋白的免疫组织化学定位。没有任何神经突生长的肺上皮区域对层粘连蛋白有大量免疫反应性。此外，对胚胎肺和唾液腺提取物的蛋白质印迹分析表明，按蛋白质计算，肺中存在与唾液腺相同数量或更多的层粘连蛋白。一种针对层粘连蛋白的抗血清和一种在体外阻断轴突在基膜上再生的单克隆抗体（INO）无法阻断轴突在固定上皮上的生长。这表明除层粘连蛋白外的其他分子负责轴突在唾液腺上皮上的优先生长。
