Ultrastructural distribution of glycinergic and GABAergic neurons and axon terminals in the rat dorsal cochlear nucleus, with emphasis on granule cell areas
Ultrastructural distribution of glycinergic and GABAergic neurons and axon terminals in the rat dorsal cochlear nucleus, with emphasis on granule cell areas
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DOI：
10.1046/j.1469-7580.2003.00208.x
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发表时间：
2003-07-01
影响因子：
2.4
通讯作者：
Alibardi, L
中科院分区：
文献类型：
--
作者：
Alibardi, L
了解大鼠耳蜗核复合体神经元中的神经递质对于理解听觉回路的功能具有重要意义。用包埋后免疫金标记法研究了大鼠耳蜗背核（DCN）分子层、梭形层和多形层内甘氨酸能和γ-氨基丁酸能神经元及轴突终末的分布。该技术不受预包埋方法中抗体渗透到神经组织中的限制，并且允许神经组织的精细神经化学映射。许多甘氨酸能和GABA能轴突终末含有多形性和扁平的突触囊泡，并存在于耳蜗背核的所有层（1，2，3）。甘氨酸和GABA阴性大终末（苔藓纤维）主要见于第2层（梭形层）的颗粒细胞区。苔藓纤维接触GABA和甘氨酸阴性颗粒细胞和少数单极刷状细胞（兴奋性神经元）的树突。颗粒细胞区中最不常见的细胞是GABA能和甘氨酸能高尔基星状神经元。在单极刷状细胞中，囊泡的聚集似乎是其特征性小环体的起源。高尔基-星状细胞将其抑制性终末发送到颗粒和单极刷状细胞的树突，偶尔直接发送到苔藓纤维。小的或大的GABA能终末（较少）接触单极刷状细胞的索马或主树突。提出了DCN中神经元的一个假设功能单元的电路。来自听觉性或非听觉性的非音调性苔藓纤维的输入最终通过颗粒细胞或单极刷状细胞的轴突到达锥体细胞。锥体细胞将兴奋信号从DCN传递到更高的中脑核团，以进一步阐述声学信号。
A knowledge of neurotransmitters in the neurons of the rat cochlear nuclear complex is of importance in understanding the function of auditory circuits. Using post-embedding ultrastructural immunogold labelling, the distribution of glycinergic and GABAergic neurons and axonal terminals has been studied in the molecular, fusiform and polymorphic layers of the rat dorsal cochlear nucleus (DCN). This technique is not limited by the penetration of antibodies into the nervous tissue as in pre-embedding methods, and allows a fine neurochemical mapping of the nervous tissue. Numerous glycinergic and GABAergic axon terminals contain pleomorphic and flat synaptic vesicles, and are present in all layers (1, 2, 3) of the dorsal cochlear nucleus. Glycine and GABA-negative large terminals (mossy fibres) are mainly seen in granule cell areas of layer 2 (fusiform layer). Mossy fibres contact the dendrites of GABA- and glycine-negative granule cells and of the few unipolar brush cells (excitatory neurons). The least common cells in the granule cell areas are GABAergic and glycinergic Golgi-stellate neurons. In unipolar brush cells, aggregations of vesicles seem to be the origin of their characteristic ringlet-bodies. Golgi-stellate cells send their inhibitory terminals to the dendrites of granule and unipolar brush cells, occasionally directly to mossy fibres. Small or (less frequently) large GABAergic terminals contact the soma or the main dendrite of unipolar brush cells. The circuit of a hypothetical functional unit of neurons in the DCN is proposed. The inputs from auditory tonotopic or nonauditory non-tonotopic mossy fibres eventually reach pyramidal cells through axons from the granule cells or unipolar brush cells. Pyramidal cells convey an excitatory signal from the DCN to higher mesencephalic nuclei for further elaboration of the acoustic signal.