The effects of a long term dihydroergotoxine treatment on agonist and antagonist striatal dopamine binding sites are dose and age related.
Chronic administration of dihydroergotoxine, at the two doses of 2.5 mg/kg and 5 mg/kg decreases the binding of dopamine 3H-agonists to striatal membranes. By contrast the binding of dopamine 3H-antagonists is decreased in the animals treated with the higher dose and increased in those treated with the lower one. In old rats, in which a partial loss of both 3H-antagonist and 3H-agonist binding sites is observed, the DHT treatment confirms to increase the binding of 3H-antagonists, without affecting that of 3H-agonists. Thus, aging and ergot alkaloids seem to discrimate between DA-agonist and DA-antagonist receptor sites suggesting that this receptors are separate entityes.
D000375:Aging; D000818:Animals; D001058:Apomorphine / Q000031:analogs & derivatives / Q000378:metabolism; D001667:Binding, Competitive / Q000187:drug effects; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004088:Dihydroergotoxine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D013134:Spiperone / Q000378:metabolism
D011954:Receptors, Dopamine; D004088:Dihydroergotoxine; D013134:Spiperone; C009074:N-n-propylnorapomorphine; D001058:Apomorphine