Effects of D-galactose on the expression of hippocampal peripheral-type benzodiazepine receptor and spatial memory performances in rats.

The changes in spatial memory performances and the binding of hippocampal peripheral-type benzodiazepine receptor (PBR) induced by D-galactose (D-gal) were investigated in rats. The animals were randomly divided into two groups: saline-treated group and D-gal-induced aging group. All rats received 56 days of injection followed by 5 days of behavioral tests. The D-gal-induced aging rats presented significant impairment in water maze performance, compared with that in the saline-treated rats. A significant decrease in [3H]PK11195 binding in the synaptosomes from hippocampus in the D-gal-induced aging rats was observed, compared to that in the saline-treated rats. Meanwhile, the Scatchard analysis revealed that there was a decrease in Bmax, with no significant change in KD. Further analysis demonstrated that water maze performance was closely related to the PK11195 binding in all rats. These results suggest that D-gal decreased the density of PBR in hippocampal synaptosomes, which may be attributable to the progressive pathogenesis of aging in rats.