title: Haloperidol versus risperidone on rat "early onset" vacuous chewing.
abstract: Similarly to acute rat catalepsy, "early onset" vacuous chewing movements (VCMs) induced by subchronic treatment with antipsychotic have recently been proposed as a model of human extrapyramidal symptoms. In the present study, the propensities of haloperidol and risperidone in inducing rat "early onset" VCMs were compared using doses of the two antipsychotics that acutely induce similar catalepsy. Comparable rat catalepsy states were observed when the effects produced by 0.1, 0.5, and 1mg/kg of haloperidol were compared with those induced by 1, 4, and 10mg/kg of risperidone, respectively. These doses of the two antipsychotics were then administered twice a day for 4 weeks and VCMs scored after 12h, 5 days, or 3 weeks of drug withdrawal. Among the haloperidol-treated groups, only those rats injected with 0.5 and 1mg/kg showed high levels of VCMs after 12h and 5 days of drug withdrawal when compared to vehicle-treated rats, while basal levels of VCMs were reached after 3 weeks from the last injection. High VCMs levels were observed in risperidone-treated rats only at the dose of 10mg/kg and after 12h of drug withdrawal, but not after 5 days or 3 weeks. The present results indicated that haloperidol possessed a much higher propensity to induce rat "early onset" VCMs than risperidone.
authors.affiliation: Neuroscienze S.c.ar.l., Via Palabanda 9, 09123, Cagliari, Italy. giorgio.marchese@ns.crs4.it
authors.forename: Giorgio
authors.initials: G
authors.lastname: Marchese
authors.forename: Francesco
authors.initials: F
authors.lastname: Bartholini
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Casu
authors.forename: Stefania
authors.initials: S
authors.lastname: Ruiu
authors.forename: Paola
authors.initials: P
authors.lastname: Casti
authors.forename: Elena
authors.initials: E
authors.lastname: Congeddu
authors.forename: Simone
authors.initials: S
authors.lastname: Tambaro
authors.forename: Luca
authors.initials: L
authors.lastname: Pani
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D002375:Catalepsy / Q000139:chemically induced; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004409:Dyskinesia, Drug-Induced / Q000503:physiopathology*; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D008409:Mastication / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018967:Risperidone / Q000494:pharmacology*; D013239:Stereotyped Behavior / Q000187:drug effects*; D013997:Time Factors
chemical_list: D014150:Antipsychotic Agents; D006220:Haloperidol; D018967:Risperidone