Maturation of Purkinje cells in mouse cerebellum after neonatal administrations of cytosine arabinoside

ICR-JCL strain mice were injected subcutaneously with 30 mg/kg body weight of cytosine arabinoside at 2, 3, and 4 days of age. This chemical prevented the production of the basket cells, stellate cells, and granule cells in the external granular layer of the cerebellum. Decrease in number of these microneutrons affected the noraml synaptic connections between the Purkinje cells and the microneurons, thus causing the disarrangement and abnormal arborization of the Purkinje cells. Of the three types of microneurons, the basket and a few stellate cells played a more important role in the disarrangement of the Purkinje cells and abnormal arborization of their primary dendrites than the granule cells did. Abnormal outgrowing directions of other smooth dendrites of the Purkinje cells were caused mainly by the diminution of stellate cells. Although parallel fibers were grossly decreased in number in the treated cerebellums, spines of the spiny dendrites of the Purkinje cells sprouted considerably in the 15-day-old mice, and then their morphological features remained even after 100 days of age.