DEVELOPMENTAL AND AGE-RELATED ALTERATIONS IN RAT-BRAIN PRESYNAPTIC DOPAMINERGIC MECHANISMS

Age-related changes in both pre- and post-synaptic components of dopam ine neurons have been demonstrated in humans as well as in animals. Ou r study was designed to examine the effects of age on presynaptic DA n eurons. To assess the developmental changes in rat striatal dopamine c arrier, we used [H-3]GBR 12935, which binds selectively to this transp orter. In addition we monitored changes in amphetamine- and KCl-induce d [H-3]DA release from rat striatal slices. We were able to demonstrat e age dependent changes in DA transporter density, which reached a pea k at age 3 months. Amphetamine-induced released of stored DA was exact ly reversed, with a nadir at age 3 months. We assumed that the combina tion of low DA transporter level with increased transporter-mediated D A release may have a major compensatory role with respect to the maint enance of dopaminergic transmission during normal development, aging a nd neuro-degenerative diseases.