Bishop G A, Ho R H
Brain Res. 1985 Apr 8;331(2):195-207. doi: 10.1016/0006-8993(85)91545-8.
The distribution of serotonin immunoreactivity in the rat cerebellum was studied using the indirect antibody peroxidase-antiperoxidase (PAP) technique of Sternberger. Furthermore, the origin of these chemically defined cerebellar afferents was studied using a procedure which combines the retrograde transport of horseradish peroxidase (HRP) with the PAP technique. Serotoninergic fibers and varicosities distribute throughout the cerebellar cortex. However, within the cortex there are density variations in the distribution of this indoleamine to the granule cell and molecular layers as well as differences in the spatial orientation of labeled elements, especially in the latter lamina. Serotonin-positive fibers are also present in the Purkinje cell layer. Some of the fibers pass from this layer into the overlying molecular layer while others form a plexus around the somata of Purkinje cells. Subsequent to injections of HRP into the vermis and immediately adjacent portions of the cerebellar cortex, several reticular and raphe nuclei (n.) were found to project to the cerebellum including the paramedian reticular nucleus, n. raphe pallidus, n. raphe obscurus, n. raphe magnus, n. reticularis gigantocellularis, n. reticularis paragigantocellularis, n. pontis oralis, n. reticularis tegmenti pontis and n. centralis superioris. Double-labeling experiments, however, reveal that the neurons giving rise to serotoninergic afferents to the cerebellum are located almost exclusively in the n. reticularis gigantocellularis, the n. reticularis paragigantocellularis and the n. pontis oralis. In conclusion, the findings of the present study further support the view that the cerebellar cortex is not uniform in its histological structure. Although serotoninergic elements are distributed throughout the cerebellar cortex, there are lobular variations in the laminar distribution of this indoleamine. These data suggest that serotonin may be exerting its physiological effect on different populations of cortical neurons in different lobules. Thus this putative neurotransmitter may play different roles in the circuitry of the cerebellum in disparate regions of the cortex. Further, the data obtained in the double-label experiments demonstrate a fairly restricted origin for serotoninergic afferents in the medullary and pontine reticular formation. Moreover, the majority are not located in the raphe nuclei.
采用斯特恩伯格的间接抗体过氧化物酶-抗过氧化物酶（PAP）技术，研究了大鼠小脑5-羟色胺免疫反应性的分布。此外，运用一种将辣根过氧化物酶（HRP）逆行运输与PAP技术相结合的方法，研究了这些化学性质明确的小脑传入神经的起源。5-羟色胺能纤维和膨体分布于整个小脑皮质。然而，在皮质内，这种吲哚胺在颗粒细胞层和分子层的分布存在密度差异，且标记元素的空间取向也有所不同，尤其是在分子层。浦肯野细胞层中也存在5-羟色胺阳性纤维。一些纤维从该层进入上方的分子层，而另一些则在浦肯野细胞的胞体周围形成丛。将HRP注入小脑蚓部和小脑皮质紧邻部位后，发现多个网状核和中缝核投射至小脑，包括旁正中网状核、中缝苍白核、中缝隐核、中缝大核、巨细胞网状核、旁巨细胞网状核、脑桥嘴侧核、脑桥被盖网状核和上中央核。然而，双重标记实验显示，向小脑发出5-羟色胺能传入神经的神经元几乎仅位于巨细胞网状核、旁巨细胞网状核和脑桥嘴侧核。总之，本研究结果进一步支持了小脑皮质组织结构并非均匀一致的观点。尽管5-羟色胺能成分分布于整个小脑皮质，但这种吲哚胺在层状分布上存在小叶差异。这些数据表明，5-羟色胺可能在不同小叶的不同皮质神经元群体上发挥其生理作用。因此，这种假定的神经递质可能在小脑皮质不同区域的神经回路中发挥不同作用。此外，双重标记实验获得的数据表明，延髓和脑桥网状结构中5-羟色胺能传入神经的起源相当局限。而且，大多数不在中缝核中。
