Age-related quantitative changes in inhibitory axo-somatic synapses on Purkinje cells of rat neocerebellum (Crus I and Crus II)

: Morphometric analysis concerning inhibitory axo-somatic synapses on the somata of rat Purkinje cells was carried out. The percentage and the absolute cell surface area occupied with the synaptic junctions as well as their surface-to-somatic volume ratio exhibited significant changes with ageing (from 2 to 24 months). All the parameters revealed the smallest value at 2 months and a peak at 9 months; then, after a decline towards 12 months, they remained fairly constant until 24 months. It is suggested that the observed modifications in the synaptic parameters of the somata would have some connection with compensatory mechanisms for dendritic deafferentation seen with ageing or with the onset and development of the reproductive life of the animals.