Haloperidol-induced vacuous chewing in rats: suppression by alpha-methyl-tyrosine.
Chronic treatment of rats with haloperidol (1 mg/kg twice daily for 4 weeks) induced repetitive vacuous chewing movements (VC), that persisted for over 72 h after haloperidol withdrawal. Haloperidol-induced VC were inhibited by the s.c. administration of the specific dopamine D1, receptor antagonist, SCH 23390 (0.025-0.100 mg/kg), in a dose-dependent manner, and were totally suppressed by an acute challenge with haloperidol (2 mg/kg i.p.) and by the dopamine synthesis inhibitor, alpha-methyl-tyrosine (AMT) (200 mg/kg i.p.). In AMT-treated rats, VC were reinstated by the administration of the selective D1 agonist, SKF 38393. The results support the hypothesis that chronic haloperidol-induced VC are mediated by dopamine acting selectively upon D1 receptors.
B.B. Brodie Department of Neuroscience, University of Cagliari, Italy.
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D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D014150:Antipsychotic Agents / Q000009:adverse effects; D001522:Behavior, Animal / Q000187:drug effects; D004195:Disease Models, Animal; D004298:Dopamine / Q000502:physiology; D004409:Dyskinesia, Drug-Induced / Q000209:etiology; D006220:Haloperidol / Q000037:antagonists & inhibitors*; D008297:Male; D008409:Mastication / Q000187:drug effects*; D008781:Methyltyrosines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D019805:alpha-Methyltyrosine
D014150:Antipsychotic Agents; D008781:Methyltyrosines; D011954:Receptors, Dopamine; D019805:alpha-Methyltyrosine; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D006220:Haloperidol; D004298:Dopamine