Effects of ageing on dendritic arborizations, dendritic spines and somatic configurations of cerebellar Purkinje cells of old cat.

We investigated the morphological alterations in the Purkinje cells (PCs) of the cerebellar cortex of young adult (2-3 years old) and old cats (12-13 years old). Rapid Golgi staining was used to visualize dendritic arborizations and spines, and routine Nissl staining was applied to visualize the somatic configuration of the PCs. The height, width and area of the dendritic network were measured, the spine density was calculated, and the average volumes of the soma and nucleus of PCs were roughly estimated. Golgi staining demonstrated that old PCs exhibited significant retraction of dendritic arborizations and considerable desquamation of dendritic spines, indicating a remarkable decrease of information input to the ageing PCs. In addition, Nissl staining showed a distinct reduction in size of the soma and nucleus of old PCs. We suggest that retraction of dendritic arborizations and degeneration of the somatic configuration might lead to deficits in information processing and substance synthesis in senile cerebellar PCs.