Wickesberg R E, Whitlon D, Oertel D
Department of Neurophysiology, University of Wisconsin, Madison 53706.
J Comp Neurol. 1994 Jan 15;339(3):311-27. doi: 10.1002/cne.903390302.
Previous studies indicate that tuberculoventral and cartwheel cells in the dorsal cochlear nucleus as well as a group of stellate cells in the ventral cochlear nucleus are likely to be glycinergic. To test whether these neurons contain higher levels of free glycine than cells that are probably not glycinergic, immunocytochemical studies with antibodies against glycine conjugates were undertaken on slices of the murine cochlear nuclear complex. Present results show that the cell bodies of all three groups of neurons are immunolabeled. However, the somatic labeling of the tuberculoventral and cartwheel cells can be modulated by experimental conditions. In slices fixed immediately after cutting, many cell bodies in the deep layer of the dorsal cochlear nucleus (DCN), presumably tuberculoventral neurons, are labeled. As a slice is incubated in vitro, cell bodies in the deep layer of the DCN lose their glycine-like immunoreactivity. After 7 hours in vitro, labeled cells are absent in the deep DCN, but the immunoreactivity can be regained by electrically stimulating the auditory nerve for 20 minutes. The loss of immunoreactivity is prevented by electrical stimulation, by axotomy, and by inclusion of 0.8 microM tetrodotoxin, or 1 microM strychnine, or 50 microM colchicine or 50 microM beta-lumicolchicine in the bathing saline. Cartwheel cells retain their immunoreactivity during incubation in vitro without electrical stimulation, but lose it under two conditions. One is following a cut across the ventral cochlear nucleus (VCN) that severs most of their granule cell input, and the other is the inclusion of tetrodotoxin in the bathing saline. The labeling of cell bodies in the ventral cochlear nucleus and of puncta and processes is not changed by any of these experimental manipulations.
先前的研究表明，耳蜗背侧核中的结核腹侧细胞和车轮状细胞以及耳蜗腹侧核中的一组星状细胞可能是甘氨酸能的。为了测试这些神经元是否比可能不是甘氨酸能的细胞含有更高水平的游离甘氨酸，对小鼠耳蜗核复合体切片进行了用抗甘氨酸缀合物抗体的免疫细胞化学研究。目前的结果表明，所有三组神经元的细胞体都有免疫标记。然而，结核腹侧细胞和车轮状细胞的体细胞标记可受实验条件调节。在切割后立即固定的切片中，耳蜗背侧核（DCN）深层的许多细胞体，可能是结核腹侧神经元，被标记。随着切片在体外孵育，DCN深层的细胞体失去其甘氨酸样免疫反应性。在体外7小时后，深层DCN中没有标记细胞，但通过电刺激听神经20分钟可恢复免疫反应性。免疫反应性的丧失可通过电刺激、轴突切断以及在浴盐中加入0.8微摩尔河豚毒素、1微摩尔士的宁、50微摩尔秋水仙碱或50微摩尔β-光秋水仙碱来防止。车轮状细胞在无电刺激的体外孵育过程中保留其免疫反应性，但在两种情况下会丧失。一种是在横切耳蜗腹侧核（VCN）切断其大部分颗粒细胞输入后，另一种是在浴盐中加入河豚毒素。耳蜗腹侧核中细胞体以及斑点和突起的标记不受任何这些实验操作的影响。
