The relationship between parkinsonism and tardive dyskinesia.
The author analyzes parkinsonism and hyperkinesia in psychiatric patients with tardive dyskinesia before and during treatment with alpha-methyl-p-tyrosine (AMPT, a dopamine antagonist), biperiden (an acetylcholine antagonist), and baclofen (a GABA agonist); and in patients with paralysis agitans and L-dopa-induced hyperkinesia. AMPT and baclofen had similar influences on oral dyskinesia, resulting in reduced frequency, unchanged or slightly reduced amplitude, and increased duration of each movement. The author concludes that: 1) reduced dopaminergic activity may be the primary pathogenetic background for tardive dyskinesia; 2) dopaminergic hypersensitivity and/or cholinergic hypofunction is necessary before hyperkinesia breaks through; and 3) the neurotoxic effects of neuroleptics may be associated with age-dependent changes in nigrostriatal regions representing oral innervation.
D000367:Age Factors; D000613:Aminobutyrates / Q000627:therapeutic use*; D001418:Baclofen / Q000627:therapeutic use*; D001479:Basal Ganglia / Q000503:physiopathology; D001712:Biperiden / Q000627:therapeutic use*; D002794:Choline / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D004409:Dyskinesia, Drug-Induced / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D007980:Levodopa / Q000009:adverse effects; D008781:Methyltyrosines / Q000627:therapeutic use*; D009055:Mouth / Q000294:innervation; D010300:Parkinson Disease / Q000188:drug therapy* / Q000378:metabolism; D010880:Piperidines / Q000627:therapeutic use*; D014149:Tranquilizing Agents / Q000009:adverse effects
D000613:Aminobutyrates; D008781:Methyltyrosines; D010880:Piperidines; D014149:Tranquilizing Agents; D001712:Biperiden; D007980:Levodopa; D001418:Baclofen; D002794:Choline; D004298:Dopamine