Oland L A, Tolbert L P, Mossman K L
Department of Anatomy and Cell Biology, Georgetown University School of Medicine, Washington, D.C. 20007.
J Neurosci. 1988 Jan;8(1):353-67. doi: 10.1523/JNEUROSCI.08-01-00353.1988.
Interactions between neurons and between neurons and glial cells have been shown by a number of investigators to be critical for normal development of the nervous system. In the olfactory system of Manduca sexta, sensory axons have been shown to induce the formation of synaptic glomeruli in the antennal lobe of the brain (Hildebrand et al., 1979). Oland and Tolbert (1987) found that the growth of sensory axons into the developing antennal lobe causes changes in glial shape and disposition that presage the establishment of glomeruli, each surrounded by a glial envelope. Several lines of evidence lead us to hypothesize that the glial cells of the lobe may be acting as intermediaries in developmental interactions between sensory axons and neurons of the antennal lobe. In the present study, we have tested this hypothesis by using gamma-radiation to reduce the number of glial cells at a time when neurons of the antennal system are postmitotic but glomeruli have not yet developed. When glial numbers are severely reduced, the neuropil of the resulting lobe lacks glomeruli. Despite the presence of afferent axons, the irradiated lobe has many of the features of a lobe that developed in the absence of afferent axons. Our findings indicate that the glial cells must play a necessary role in the inductive influence of the afferent axons.
许多研究人员已经表明，神经元之间以及神经元与神经胶质细胞之间的相互作用对于神经系统的正常发育至关重要。在烟草天蛾的嗅觉系统中，感觉轴突已被证明可诱导大脑触角叶中突触小球的形成（希尔德布兰德等人，1979年）。奥兰德和托尔伯特（1987年）发现，感觉轴突向发育中的触角叶生长会导致神经胶质细胞的形状和分布发生变化，这预示着小球的形成，每个小球都被一个神经胶质包膜所包围。几条证据线索使我们推测，叶中的神经胶质细胞可能在感觉轴突与触角叶神经元之间的发育相互作用中充当媒介。在本研究中，我们通过使用伽马辐射在触角系统的神经元处于有丝分裂后期但小球尚未发育时减少神经胶质细胞的数量来检验这一假设。当神经胶质细胞数量严重减少时，所形成叶的神经纤维网缺乏小球。尽管存在传入轴突，但受辐射的叶具有许多在没有传入轴突的情况下发育的叶的特征。我们的研究结果表明，神经胶质细胞必须在传入轴突的诱导影响中发挥必要作用。
