title: Enkephalin receptor changes in rat brain during aging.
abstract: In experiments on 2-, 10- and 22-month-old rats, it was found that the number (Bmax) of brain enkephalin (Enk) receptors decreased with aging. The Bmax values in the cortex of 22-month-old rats decreased by 57%, in the striatum by 33% and in the hypothalamus by 84% as compared to those in 2-month-old rats. The Enk receptor sensitivity in the brain of aged rats also decreased (increased Kd). It is suggested that the changes in opiate receptors play a role in the age-related reduction of the adaptive capacity of the organism. The studies with repeated administration of L-dopa or haloperidol provided further evidence for interactions between opiate and dopaminergic systems.
mesh_terms: D000375:Aging; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D006220:Haloperidol / Q000494:pharmacology; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology*; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology*
chemical_list: D011957:Receptors, Opioid; D007980:Levodopa; D006220:Haloperidol