Aged Changes of Glu/GABA Expression in the Cerebellar Cortex of Cats

The physiological function of cerebellum declines during ageing, but its neural mechanism is not still clear. Therefore, we applied an immunohistochemical method to exhibit the Glu and GABA immunoreactive (Glu-IR and GABA-IR) cells, to investigate aged changes of Glu/GABA expression in the cerebellar cortex of young adult and old cats, and to discuss the possible impact of these changes. Under the Olympus BX-51 light microscope, the density of the immunoreactive cells and its gray value in the molecular layer, Purkinje layer and granular layer were counted respectively with Image-Pro Express Software 5.1. Compared with young cats, the density and average grey value of Glu immunoreactive cells increased significantly in the Purkinje and granular layer of old cats (P<0.01). The density and intensity of GABA immunoreactive neurons declined significantly in the molecular and Purkinje layers of old cats (P<0.01). The density of GABA immunoreactive neurons showed no evident differences in the granular layer between young and old cats (P>0.05), but the intensity of GABA immunoreactive neurons was visibly weaker in the granular layer of old cats (P<0.01). The results indicated that changes of Glu/GABA expression in the cerebellar cortex during ageing may be one of the important factors mediating the functional degeneration of accurate timing and neurons lost in old individuals.

Keywords
Glu (Glutamate); GABA (g-Aminobutiric acid); Ageing; Cerebellar cortex; Cat