Heckroth J A, Goldowitz D, Eisenman L M
Department of Anatomy, Jefferson Medical College, Philadelphia, Pennsylvania 19107.
J Comp Neurol. 1990 Jan 15;291(3):415-30. doi: 10.1002/cne.902910308.
Olivocerebellar fiber maturation was examined in normal and lurcher mutant mice between postnatal day 5 (P5) and P15, using the anterograde transport of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) from the inferior olive. Immunocytochemistry for the Purkinje cell marker PEP-19 was used to demonstrate Purkinje cell development in the same material. In mutant and normal animals, a regional developmental variation is observed such that, when compared at a given age, cortex lining the vermal fissures appears developmentally advanced over cortex in the cerebellar hemispheres. In the primary fissure of the normal animals, the first recognizable Purkinje cell dendrites appear on P6, and the olivocerebellar fibers first enter the climbing stage of their development on P9. In lurcher animals Purkinje cell development proceeds on this schedule, but olivocerebellar fibers are never observed to enter the molecular layer. These afferents maintain dense perisomatic nests around Purkinje cells, even in P13-15 lurchers. Examination of P14 lurchers by transmission electron microscopy indicates that the olivocerebellar fibers form synapses on Purkinje cell somatic spines and that the basket cell axons fail to form their typical perisomal nests around Purkinje cells. In addition, parallel fibers can be observed to synapse on dendritic spines on the Purkinje cell primary dendrites. We interpret these results as indicating a recognition defect between olivocerebellar fibers and Purkinje cell dendrites. An analysis of this defect in lurcher may reveal how the normal transformation of olivocerebellar fibers, from perisomal to dendritic terminals, is achieved.
利用从下橄榄核进行的小麦胚凝集素-辣根过氧化物酶（WGA-HRP）顺行运输，在出生后第5天（P5）至第15天期间，对正常和蹒跚突变小鼠的橄榄小脑纤维成熟情况进行了研究。使用浦肯野细胞标志物PEP-19的免疫细胞化学方法，在相同材料中显示浦肯野细胞的发育情况。在突变和正常动物中，观察到一种区域发育差异，即在给定年龄进行比较时，蚓部裂沟内衬的皮质在发育上比小脑半球的皮质更先进。在正常动物的原裂中，最早可识别的浦肯野细胞树突出现在P6，橄榄小脑纤维在P9首次进入其发育的攀缘阶段。在蹒跚动物中，浦肯野细胞的发育按此时间表进行，但从未观察到橄榄小脑纤维进入分子层。即使在P13 - 15的蹒跚动物中，这些传入纤维也在浦肯野细胞周围维持密集的胞体周围巢状结构。通过透射电子显微镜对P14的蹒跚动物进行检查表明，橄榄小脑纤维在浦肯野细胞体棘上形成突触，并且篮状细胞轴突未能在浦肯野细胞周围形成其典型的胞体周围巢状结构。此外，可以观察到平行纤维在浦肯野细胞初级树突上的树突棘上形成突触。我们将这些结果解释为表明橄榄小脑纤维与浦肯野细胞树突之间存在识别缺陷。对蹒跚动物中这种缺陷的分析可能揭示橄榄小脑纤维从胞体末端到树突末端的正常转变是如何实现的。
