Calbindin D-28k immunoreactivity in the rat cerebellar cortex: age-related changes

The present study was designed to analyze age-dependent changes in the expression of calbindin D-28k immunoreactivity in the cerebellar cortex of male Wistar rats aged 3 months (young), 12 months (adult) and 24 months (old). Calbindin D-28k immunoreactivity was localized primarily in the cytoplasm of Purkinje neurons and in the basal portion of their dendritic processes entering in the molecular layer. The expression of calbindin D-28k immunoreactivity was highest in Purkinje neurons of adult rats and lowest in Purkinje neurons of old rats. Moreover, the number of Purkinje neurons displaying calbindin D-28k immunoreactivity was decreased in aged rats. These results demonstrate the occurrence of age-related-changes in the expression of immunoreactivity of the Ca²⁺ binding protein calbindin D-28k in the rat cerebellar cortex. The possibility that impairment in the expression of Ca²⁺ binding proteins may be involved in changes of intracellular Ca²⁺ homeostasis reported in aging and in some neuro-degenerative disorders is discussed.