Ultrastructural characterization of the acetylcholine innervation in adult rat neostriatum
Ultrastructural characterization of the acetylcholine innervation in adult rat neostriatum
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DOI：
10.1016/0306-4522(95)00507-2
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发表时间：
1996-04-01
期刊：
影响因子：
3.3
通讯作者：
Descarries, L
中科院分区：
文献类型：
--
作者：
Contant, C;Umbriaco, D;Descarries, L
用抗大鼠胆碱乙酰转移酶单克隆抗体免疫组化染色后，电镜观察成年大鼠新纹状体乙酰胆碱轴突终末（静脉曲张）的超微结构特征。从这些静脉曲张的几百个单一的部分进行了分析的形状，大小和内容，存在的突触膜专业化，和组成的微环境。从相同显微照片中随机选择相同数量的未标记静脉曲张进行类似检查。免疫染色的静脉曲张轮廓相对较小，很少表现出连接膜特化。体视学外推到这些静脉曲张的整个体积表明，不到10%的突触。很少树突棘并列这些占主导地位的突触配置文件比他们的未标记的同行。这种差异似乎归因于乙酰胆碱静脉曲张的突触发生率较低，并且与这些静脉曲张相对于周围元素随机分布的观点一致，大部分数据提示了体积传输。这提出了一种可能性，即在这样一个神经支配密集的区域，乙酰胆碱的基础水平永久地保持在所有细胞成分周围，有助于这种递质的调节特性。乙酰胆碱的基础水平也可以作为控制神经元、神经胶质和血管中不同受体亚型表达的调节信号。
The ultrastructural features of acetylcholine axon terminals (varicosities) in adult rat neostriatum were characterized by electron microscopy after immunostaining with a sensitive monoclonal antibody against rat choline acetyltransferase. Several hundred single sections from these varicosities were analysed for shape, size and content, presence of a synaptic membrane specialization, and composition of the microenvironment. An equivalent number of unlabeled varicosities selected at random from the same micrographs were similarly examined. The immunostained varicosity profiles were relatively small and seldom showed a junctional membrane specialization. Stereological extrapolation to the whole volume of these varicosities indicated that less than 10% were synaptic. Far fewer dendritic spines were juxtaposed to these predominantly asynaptic profiles than to their unlabeled counterparts. This difference seemed imputable to the low synaptic incidence of the acetylcholine varicosities and was consistent with the view that these are randomly distributed in relation to surrounding elements.The bulk of the data was suggestive of volume transmission. This raised the possibility that, in such a densely innervated area, a basal level of acetylcholine is permanently maintained around all cellular elements, contributing to the modulatory properties of this transmitter. This basal level of acetylcholine could also serve as a regulatory signal controlling the expression of different receptor subtypes in neurons, glia and blood vessels.