Gómez C, Briñón J G, Barbado M V, Weruaga E, Valero J, Alonso J R
Lab. Plasticidad neuronal y neurorreparación, Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Spain.
J Chem Neuroanat. 2005 Jun;29(4):238-54. doi: 10.1016/j.jchemneu.2005.01.005. Epub 2005 Apr 1.
The centrifugal systems innervating the olfactory bulb are important elements in the functional regulation of the olfactory pathway. In this study, the selective innervation of specific glomeruli by serotonergic, noradrenergic and cholinergic centrifugal axons was analyzed. Thus, the morphology, distribution and density of positive axons were studied in the glomerular layer of the main olfactory bulb of the rat, using serotonin-, serotonin transporter- and dopamine-beta-hydroxylase-immunohistochemistry and acetylcholinesterase histochemistry in serial sections. Serotonin-, serotonin transporter-immunostaining and acetylcholinesterase-staining revealed a higher heterogeneity in the glomerular layer of the main olfactory bulb than previously reported. In this sense, four types of glomeruli could be identified according to their serotonergic innervation. The main distinctive feature of these four types of glomeruli was their serotonergic fibre density, although they also differed in their size, morphology and relative position throughout the rostro-caudal main olfactory bulb. In this sense, some specific regions of the glomerular layer were occupied by glomeruli with a particular morphology and a characteristic serotonergic innervation pattern that was consistent from animal to animal. Regarding the cholinergic system, we offer a new subclassification of glomeruli based on the distribution of cholinergic fibres in the glomerular structure. Finally, the serotonergic and cholinergic innervation patterns were compared in the glomerular layer. Sexual differences concerning the density of serotonergic fibres were observed in the atypical glomeruli (characterized by their strong cholinergic innervation). The present report provides new data on the heterogeneity of the centrifugal innervation of the glomerular layer that constitutes the morphological substrate supporting the existence of differential modulatory levels among the entire glomerular population.
支配嗅球的离心系统是嗅觉通路功能调节的重要组成部分。在本研究中，分析了血清素能、去甲肾上腺素能和胆碱能离心轴突对特定肾小球的选择性支配。因此，利用连续切片中的血清素、血清素转运体和多巴胺-β-羟化酶免疫组织化学以及乙酰胆碱酯酶组织化学，研究了大鼠主嗅球肾小球层中阳性轴突的形态、分布和密度。血清素、血清素转运体免疫染色和乙酰胆碱酯酶染色显示，主嗅球肾小球层的异质性高于先前报道。从这个意义上说，根据血清素能支配情况可识别出四种类型的肾小球。这四种类型肾小球的主要区别特征是其血清素能纤维密度，尽管它们在整个嗅球的头-尾方向上的大小、形态和相对位置也有所不同。从这个意义上说，肾小球层的一些特定区域被具有特定形态和特征性血清素能支配模式的肾小球占据，这种模式在不同动物之间是一致的。关于胆碱能系统，我们根据胆碱能纤维在肾小球结构中的分布对肾小球进行了新的亚分类。最后，比较了肾小球层中血清素能和胆碱能的支配模式。在非典型肾小球（以其强烈的胆碱能支配为特征）中观察到血清素能纤维密度的性别差异。本报告提供了关于肾小球层离心支配异质性的新数据，这些数据构成了支持整个肾小球群体中存在不同调节水平的形态学基础。
