title: Tolerance to haloperidol-induced increases in dopamine metabolites: fact or artifact?
abstract: Haloperidol increased 3,4-dihydroxyphenylacetic acid and homovanillic acid concentrations in the striatum, nucleus accumbens and olfactory tubercle of both drug-naive rats and rats pretreated with haloperidol (10 injections). The increases in metabolite concentrations were greater in all brain regions of the naive rats, suggesting that haloperidol pretreatment resulted in a decreased responsiveness to the drug (tolerance). However, subchronic haloperidol injections also resulted in decreased basal metabolite concentrations in rats killed 48 h after the last injection. While the response of drug-experienced rats to haloperidol was attenuated relative to that of drug-naive rats, this difference could be accounted for entirely by the decreased basal metabolite concentrations that occur after repeated haloperidol injections.
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000032:analysis*; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D003342:Corpus Striatum / Q000032:analysis; D004361:Drug Tolerance; D006220:Haloperidol / Q000494:pharmacology*; D006719:Homovanillic Acid / Q000032:analysis*; D008297:Male; D009714:Nucleus Accumbens / Q000032:analysis; D010648:Phenylacetates / Q000032:analysis*; D051381:Rats
chemical_list: D010648:Phenylacetates; D015102:3,4-Dihydroxyphenylacetic Acid; D006220:Haloperidol; D006719:Homovanillic Acid