ALPHA-2-ADRENOCEPTOR CHANGES DURING CEREBRAL AGING - THE EFFECT OF GINKGO-BILOBA EXTRACT

[H-3]Rauwolscine binding to alpha-2-adrenoceptors in cerebral cortex and hippocampus membranes of young (4 months) and aged (24 months) Wistar rats has been investigated. In aged rats, B(max) values of [H-3]rauwolscine binding were significantly reduced (25-32%) in the cerebral cortex and hippocampus, as compared with the number of alpha-2-adrenoceptors found in young rats. Chronic treatment with Ginkgo biloba extract did not alter [H-3]rauwolscine binding in the hippocampus of young rats, but significantly increased (28%) the [H-3]rauwolscine binding density in aged rats. These data confirm the previously described age-related noradrenergic alteration and suggest that noradrenergic activity in aged rats is more susceptible to Ginkgo biloba extract treatment.