Glutamate, aspartate and co-localization with calbindin in the medial thalamus - An immunohistochemical study in the rat
Glutamate, aspartate and co-localization with calbindin in the medial thalamus - An immunohistochemical study in the rat
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DOI：
10.1007/pl00005689
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发表时间：
1997-06-01
影响因子：
2
通讯作者：
Bentivoglio, M
中科院分区：
文献类型：
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作者：
Frassoni, C;Spreafico, R;Bentivoglio, M
本实验观察了大鼠丘脑内侧区天冬氨酸(ASP)或谷氨酸(GLU)作为神经递质的神经元的形态和数量特征。钙结合蛋白Calbindin D-28k(CB)被用作神经元亚群的标记，从而使我们能够研究含CB的神经元与那些对兴奋性氨基酸免疫反应的神经元之间的关系。在40 mm厚的切片上进行ASP和CB或GLU和CB的双重免疫细胞化学染色。这三种标志物分布在丘脑中线、背内侧、前板内侧和腹内侧核，具有区域性差异。在这些结构中，ASP免疫反应神经元比GLU免疫反应神经元更多，ASP-CB或GLU-CB双重免疫染色神经元明显。然后在5微米厚的连续切片上对ASP、CLU和CB免疫反应细胞进行定量评估。个体间差异以及不同的抗天冬氨酸和抗GLU抗体均未导致显著差异。天门冬氨酸氨基转移酶和谷氨酸没有共定位。单个ASP或GLU免疫阳性神经元占免疫染色细胞总数的60%，单个ASP免疫阳性细胞占这些神经元的一半以上。在CB免疫反应阳性细胞中(占总数的40%)，有一半呈双重免疫染色，CB-ASP免疫阳性神经元的比例是CB-GLU免疫反应阳性神经元的7倍。这些结果表明，在较高比例的丘脑内侧神经元中，天冬氨酸可能是兴奋性神经递质，其中天冬氨酸与CB共存的频率较高。大约50%的CB免疫反应细胞既不含天冬氨酸也不含GLU，提示丘脑内侧神经元可能使用不同的神经递质。
Topographical and quantitative features of medial thalamic neurons in which aspartate (ASP) or glutamate (GLU) might act as neurotransmitters were investigated in the rat. The calcium-binding protein calbindin D-28k (CB) was exploited as a marker of neuronal subsets, thus allowing us to study also the relationships between the CB-containing neurons and those immunoreactive to excitatory amino acids. Double immunocytochemistry of ASP and CB or GLU and CB was performed in 40-mu m-thick sections. The three markers were distributed in the thalamic midline, mediodorsal, anterior intralaminar and ventromedial nuclei, with regional variations. ASP-immunoreactive neurons appeared more numerous than the GLU-immunoreactive ones throughout these structures; ASP-CB or GLU-CB double-immunostained neurons were evident. ASP-, CLU- and CB-immunoreactive cells were then quantitatively evaluated in 5-mu m-thick consecutive sections. Interindividual variations and different anti-ASP and anti-GLU antibodies did not result in significant differences. ASP and GLU were not co-localized. Single ASP- or GLU-immunoreactive neurons accounted for 60% of the total number of immunostained cells, and single ASP-immunopositive cells represented more than half of these neurons. Among the CB-immunoreactive cells (40% of the total), half were double immunostained; the proportion of double CB-ASP-immunopositive neurons was sevenfold higher than that of the CB-GLU-immunoreactive ones. These results indicate that ASP may act as excitatory neurotransmitter in a relatively high proportion of medial thalamic neurons, in which ASP frequently coexists with CB. Approximately 50% of the CB-immunoreactive cells did not contain either ASP or GLU, suggesting that some medial thalamic neurons may utilize a different neurotransmitter.