Selective reduction of one class of dopamine receptor binding sites in the corpus striatum of aged rats.

In aged rats (21-23 vs 3 month) the neuroleptic receptor number was reduced in the striatum (--53%), in the limbic area (--36%), and not changed in the cortex. The in vitro pharmacological profile of the remaining [3H]spiroperidol receptors in each area was not modified in aged animals. The binding of [3H]ADTN (2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronapthalene) in the striatum and of [3H]serotonin ([3H]-5 HT) in the cortex was also the same in both age groups.