Similarity of age-dependent changes in renal and striatal dopamine receptors

A comparative analysis of the age-dependent changes in renal DA-1 and striatal D-1 dopamine receptors was performed in 3-(young), 12-(adult) and 27-(aged) month-old male Wistar rats by means of combined radioreceptor binding and autoradiographic techniques. 3H-SCH 23390 was used as a ligand of DA-1 or D-1 receptors. Experiments were performed on frozen sections of the kidney and of the striatum. The affinity of the ligand for both renal or striatal receptors did not show age-dependent changes. A significant loss in the density of DA-1 and D-1 sites was observed in the adult in comparison with young rats. A further decrease in the density of these sites was noticeable between adult and aged animals. These results suggest that renal DA-1 and striatal D-1 receptors are sensitive to aging to the same extent.