Brain benzodiazepine binding in aged rats

Membrane [H-3]flunitrazepam binding to central and peripheral benzodiazepine binding sites was studied in four brain areas (cerebellum, cortex, striatum and midbrain) of young (age 2-4 months) and aged (> 24 months) rats. A generalized reduction in the density of central binding sites (B-max) was observed in all brain areas examined in aged rats. This reduction is irrelevant of the brain area and, according to literature, may correspond to cell loss and/or differential expression of mRNAs coding for the subunits of the GABA/benzodiazepine receptor complex during ageing. In the case of the peripheral binding sites, there was a decrease of B-max in all brain areas with the exception of the cerebellum. However, the percent reduction of peripheral binding sites varied 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) 1998 Elsevier Science Ltd. All rights reserved.