High-affinity uptake of neurotransmitters in rat neostriatum: effects of aging.

High-affinity uptake of dopamine (DA), glutamate, and gamma-aminobutyric acid (GABA) was determined in crude synaptosomal preparations from neostriatal regions of rats 7, 17, and 27 months of age. Dopamine uptake was highest in rostral neostriatum, but no age-related differences were detected. On the other hand, the high-affinity uptake of both GABA and glutamate was increased with age. This may reflect astrocytic hypertrophy or hyperplasia, which have been reported to occur in the neostriatum during the aging process.