Rubel E W, MacDonald G H
Hearing Development Laboratories, University of Washington School of Medicine, Seattle 98195.
J Comp Neurol. 1992 Apr 22;318(4):415-25. doi: 10.1002/cne.903180406.
Removal of the cochlea or pharmacological blockade of eighth nerve activity in young postnatal chickens results in rapid transneuronal cell death and atrophy in neurons of n. magnocellularis. The present experiments were designed to examine the influence of afferent input on astrocyte structure in n. magnocellularis. Young chickens were subjected to unilateral cochlea removal. At times ranging from 5 minutes to 72 hours later, the brainstems were histologically processed with a polyclonal antibody against glial fibrillary acidic protein (GFAP). A second group of chick brainstems was impregnated by a Golgi method 6 hours after unilateral cochlea removal and impregnated three-dimensional reconstructions were made of glial cells in n. magnocellularis (NM). Analyses of GFAP positive processes in NM revealed an observable increase in the number of astrocytic processes at the borders of the nucleus within 30 minutes of cochlea removal and a twofold increase in GFAP + glial processes by 6 hours. A secondary increase in the number and density of GFAP + processes occurred between 24 and 72 hours following cochlea removal, during the period of axonal degeneration, and transneuronal cell atrophy and death. Analyses of astrocytes impregnated by the Golgi method revealed that individual glial cells had increased their total process length and the number of processes by approximately twofold by 6 hours after cochlea removal. These results suggest that the structure of astrocytes is rapidly and dramatically influenced by the level of excitatory activity in a neuronal system. Furthermore, the similarity of results obtained with GFAP immunohistochemistry and three-dimensional reconstruction of astrocytes provides evidence that the short-term changes observed following cochlea removal represent the actual growth of glial processes. We speculate that modulations in glial processes as a function of afferent activity may act to influence synaptic efficacy.
去除新生雏鸡的耳蜗或对其第八神经活动进行药理学阻断，会导致巨细胞神经核中的神经元迅速发生跨神经元细胞死亡和萎缩。本实验旨在研究传入输入对巨细胞神经核中星形胶质细胞结构的影响。对雏鸡进行单侧耳蜗切除术。在术后5分钟至72小时的不同时间点，取脑干进行组织学处理，用抗胶质纤维酸性蛋白（GFAP）的多克隆抗体进行检测。另一组雏鸡在单侧耳蜗切除术后6小时，采用高尔基法进行染色，对巨细胞神经核（NM）中的胶质细胞进行三维重建。对NM中GFAP阳性突起的分析显示，在耳蜗切除后30分钟内，核边界处星形胶质细胞突起的数量明显增加，到6小时时，GFAP + 胶质突起数量增加了两倍。在耳蜗切除后24至72小时，即轴突变性、跨神经元细胞萎缩和死亡期间，GFAP + 突起的数量和密度再次增加。对用高尔基法染色的星形胶质细胞的分析表明，在耳蜗切除后6小时，单个胶质细胞的总突起长度和突起数量增加了约两倍。这些结果表明，星形胶质细胞的结构受到神经元系统兴奋性活动水平的快速而显著的影响。此外，GFAP免疫组织化学和星形胶质细胞三维重建结果的相似性表明，耳蜗切除后观察到的短期变化代表了胶质突起的实际生长。我们推测，胶质突起根据传入活动的调节可能会影响突触效能。
