PRESERVATION OF THE DENSITY OF THE DOPAMINE UPTAKE COMPLEX IN AGING FISCHER 344 RAT-BRAIN

This study was performed to determine if there are selective regional or global changes in the density or pharmacology of the dopamine uptake complex (DAUC) in aged rodent. Fifteen regions of the Fischer 344 rat (aged 4, 12, and 24 months) central nervous system were analyzed for the density of the DAUC employing [H-3]GBR 12935 and in vitro quantitative autoradiography. Additionally, cocaine competitions were performed in the striatum of all of the animals. A 26-fold variation in the DAUC density was found in the regions sampled. However, no significant age-related changes were identified. Intrastriatal analysis of the DAUC density revealed binding heterogeneities; decreasing lateral to medial and decreasing dorsal to ventral gradients. No significant effect of aging on striatal gradients was observed. The proportion of high and low affinity sites for cocaine was unchanged in the three age groups. Taken together, these findings suggest a stability of this dopamine presynaptic marker in aging rat central nervous system.