Immuno- and histochemical data on changed GABA transmission in aged rat cerebellum.

The distribution of gamma-aminobutyric acid-immunoreactivity (GABA-I) and activity of GABA-transaminase (GABA-T) was compared in the cerebellum of young adult (3-month old) and aged (24-month old) Wistar rats. A decrease in the density and staining of GABA-immunoreactive and GABA-T positive nerve cells, fibers and puncta were observed in both cerebellar cortex and nuclei of aged rats as compared to those in young adult rats. In contrast, an increased number of Bergmann glia cell and astrocyte processes and bodies in aged rats were demonstrated in GABA immunostaining and histochemical GABA-T reaction. The changes in GABA-I and GABA-T activity provide evidence for altered GABA transmission during normal aging of rat cerebellum.