BRAIN BENZODIAZEPINE BINDING IN AGED RATS

Membrane [H-3]flunitrazepam binding to central and peripheral benzodia zepine binding sites was studied in four brain areas (cerebellum, cort ex, striatum and midbrain) of young (age 2-4 months) and aged (> 24 mo nths) rats. A generalized reduction in the density of central binding sites (B-max) was observed in all brain areas examined in aged rats. T his reduction is irrelevant of the brain area and, according to litera ture, may correspond to cell loss and/or differential expression of mR NAs coding for the subunits of the GABA/benzodiazepine receptor comple x during ageing. In the case of the peripheral binding sites, there wa s a decrease of B-max in all brain areas with the exception of the cer ebellum. However, the percent reduction of peripheral binding sites va ried significantly among the different brain areas. These data suggest a differential effect of ageing on brain benzodiazepine binding which may reflect the special role for each brain area during ageing. (C) 1 998 Elsevier Science Ltd. All rights reserved.