Tropea M, Johnson M I, Higgins D
Department of Pharmacology, School of Medicine, State University of New York, Buffalo 14214.
Glia. 1988;1(6):380-92. doi: 10.1002/glia.440010605.
Many types of glial-neuronal interactions occur during the development of the nervous system. To determine how such interactions might affect the development of autonomic ganglia, we compared the morphology of embryonic rat sympathetic neurons grown in the absence and in the presence of ganglionic nonneuronal cells in serum-free medium. Dye injections, electron microscopy, and immunocytochemistry were used to distinguish axons from dendrites. In cultures without nonneuronal cells, most (greater than 80%) sympathetic neurons extended only a single axonal process, and this unipolar state persisted for at least 8 weeks. Coculture with ganglionic nonneuronal cells caused sympathetic neurons to become multipolar and to extend multiple (range 1-17) dendrites. Morphometric measurements made after 1 month of coculture indicated that the amount of dendritic growth that occurred in vitro (mean number of dendrites/cell = 7.5; total dendritic length = 1,050 micron) was similar to that normally occurring during a comparable period in situ. In contrast to its prominent effects on dendritic growth, coculture did not cause changes in the number of axons/neuron or in the uptake of neurotransmitter. Cultures with ganglionic nonneuronal cells were immunostained for antigens present on the surfaces of fibroblasts (Thy-1.1, fibronectin) and of glia of the peripheral nervous system (laminin). Fewer than 1% of the nonneuronal cells displayed immunoreactivity for fibroblastic antigens; in contrast, greater than or equal to 99% reacted with antibody to laminin. Moreover, reconstitution experiments revealed that purified populations of laminin-positive Schwann cells promoted dendritic growth. Fibroblasts and heart cells lacked this activity. These data indicate that glia selectively promote dendritic development in sympathetic neurons maintained in serum-free medium.
在神经系统发育过程中会发生多种类型的神经胶质细胞与神经元的相互作用。为了确定这种相互作用如何影响自主神经节的发育，我们比较了在无血清培养基中，在没有神经节非神经元细胞和有神经节非神经元细胞存在的情况下生长的胚胎大鼠交感神经元的形态。通过染料注射、电子显微镜和免疫细胞化学来区分轴突和树突。在没有非神经元细胞的培养物中，大多数（超过80%）交感神经元仅伸出单个轴突过程，并且这种单极状态持续至少8周。与神经节非神经元细胞共培养导致交感神经元变为多极并伸出多个（范围为1 - 17个）树突。共培养1个月后进行的形态测量表明，体外发生的树突生长量（平均每个细胞的树突数量 = 7.5；总树突长度 = 1050微米）与在原位相当时间段内正常发生的情况相似。与它对树突生长的显著影响相反，共培养并未引起每个神经元轴突数量或神经递质摄取的变化。对含有神经节非神经元细胞的培养物进行免疫染色，检测成纤维细胞（Thy - 1.1、纤连蛋白）和外周神经系统胶质细胞（层粘连蛋白）表面存在的抗原。少于1%的非神经元细胞对成纤维细胞抗原显示免疫反应性；相反，大于或等于99%的细胞与层粘连蛋白抗体发生反应。此外，重组实验表明，纯化的层粘连蛋白阳性施万细胞群体促进树突生长。成纤维细胞和心脏细胞缺乏这种活性。这些数据表明，神经胶质细胞在无血清培养基中选择性地促进交感神经元的树突发育。
