Yamano M, Tohyama M
Department of Anatomy and Neuroscience, Osaka University Medical School, Japan.
Brain Res Dev Brain Res. 1993 Mar 19;72(1):107-17. doi: 10.1016/0165-3806(93)90164-6.
The present study analyzed the ontogeny of calcitonin gene-related peptide-like immunoreactive (CGRP-IR) structures in the mouse cerebellum. No CGRP-IR neurons were detected at any stage, but three types of CGRP-IR fibers were seen: (1) CGRP-IR dense fiber plexuses which appeared transiently in the developing cerebellum, (2) thin varicose fibers, and (3) mossy fiber-like fibers. The CGRP-IR dense fiber plexuses appeared in the developing Purkinje cell layer at postnatal day 2. From postnatal days 6 to 11, these fibers formed pericellular nests around Purkinje cells. After that stage, these fibers rapidly disappeared and no such plexuses were seen in the adult cerebellum. CGRP-IR fiber plexuses were not evenly distributed, and they had a parasagittal banded pattern in the frontal sections. These plexuses existed in the region of all vermis, crus 1 of the ansiform lobe, simplex lobule, and flocculus, while the other lobules were devoid of such fibers. Under electron microscopy, these CGRP-IR fibers were seen to make synaptic contacts with somatic spines of Purkinje cells, suggesting that CGRP-IR plexuses were closely related to the developing Purkinje cells. Mossy fiber-like CGRP-IR fibers appeared in the granular layer on postnatal day 2, and increased in number to reach a peak on postnatal day 12. Thereafter, they decreased slightly to reach a plateau on postnatal day 30. Under electron microscopy these CGRP-IR fibers were revealed to be the mossy fibers which regulated the granule cells. Thin varicose CGRP-IR fibers were rarely seen at birth, but on postnatal day 8, many fibers appeared in all layers and increased by postnatal day 30. They distributed equally throughout the cerebellar cortex with a slight predominance in density in the molecular and Purkinje cell layer. Immunoelectron microscopic analysis showed that these fibers made synaptic contacts with small dendrites in the molecular layer.
本研究分析了小鼠小脑中降钙素基因相关肽样免疫反应性（CGRP-IR）结构的个体发生。在任何阶段均未检测到CGRP-IR神经元，但可见三种类型的CGRP-IR纤维：（1）在发育中的小脑中短暂出现的CGRP-IR密集纤维丛；（2）细的曲张纤维；（3）苔藓纤维样纤维。CGRP-IR密集纤维丛在出生后第2天出现在发育中的浦肯野细胞层。从出生后第6天到第11天，这些纤维在浦肯野细胞周围形成细胞周巢。在该阶段之后，这些纤维迅速消失，在成年小脑中未见此类纤维丛。CGRP-IR纤维丛分布不均，在额叶切片中呈矢状旁带状模式。这些纤维丛存在于所有蚓部、心形叶的脚1、单小叶和绒球区域，而其他小叶则没有此类纤维。在电子显微镜下，可见这些CGRP-IR纤维与浦肯野细胞的体细胞棘形成突触联系，表明CGRP-IR纤维丛与发育中的浦肯野细胞密切相关。苔藓纤维样CGRP-IR纤维在出生后第2天出现在颗粒层，并在数量上增加，在出生后第12天达到峰值。此后，它们略有减少，在出生后第30天达到稳定水平。在电子显微镜下，这些CGRP-IR纤维被揭示为调节颗粒细胞的苔藓纤维。细的曲张CGRP-IR纤维在出生时很少见，但在出生后第8天，许多纤维出现在所有层中，并在出生后第30天增加。它们均匀分布于整个小脑皮质，在分子层和浦肯野细胞层中的密度略有优势。免疫电子显微镜分析表明，这些纤维与分子层中的小树枝状突起形成突触联系。
