Increased grooming behaviour is induced by apomorphine in mice treated with discriminant benzamide derivatives.
Grooming behaviour in mice was dose dependently increased by SK&F 38393 (1.87-30 mg/kg), whereas it was dose dependently decreased by RU 24926 (2.5-10 mg/kg) or LY 171555 (0.4-1.6 mg/kg) alone or combined with SK&F 38393 or apomorphine (0.39-6 mg/kg). The inhibitory effect of 0.75 mg/kg apomorphine on grooming behaviour was not modified by SCH 23390, chlorpromazine, clozapine and thioridazine. In contrast, it was antagonized by eight other dopamine antagonists: a partial restoration to grooming scores lower or similar to those determined in control mice was obtained with flupentixol, haloperidol, metoclopramide, thioproperazine and tiapride, whereas a reversal to grooming scores higher than those determined in control mice was obtained with mice treated with (+/-)-sulpiride, amisulpride or RIV 2093. Furthermore, only SCH 23390, chlorpromazine and clozapine antagonized SK&F 38393 (1.87 mg/kg)-induced grooming behaviour, whereas the effects of flupentixol, thioridazine, metoclopramide, haloperidol and amisulpride in SK&F 38393-treated mice were parallel to those of control mice. Finally, SCH 23390 (20 micrograms/kg) antagonized the apomorphine-induced grooming in mice treated with amisulpride, (+/-)-sulpiride or tiapride. These data confirm the potential role of D-1 dopamine receptors in the expression of grooming behaviour and indicate that the dopamine receptors involved in the inhibition of grooming could be of the D-4 subtype. Our results also reveal that chlorpromazine and clozapine have D-1 antagonist properties and suggest that the modulation of apomorphine-induced grooming behaviour by dopamine antagonists in mice could be used as a test for their classification according to their activity at the different dopamine receptor subtypes.
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Laboratoire de Physiologie (U.A. CNRS 1170), U.E.R. de Médecine-Pharmacie de Rouen, Saint Etienne du Rouvray, France.
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D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001058:Apomorphine / Q000494:pharmacology*; D001549:Benzamides / Q000494:pharmacology*; D006120:Grooming / Q000187:drug effects*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects
D014150:Antipsychotic Agents; D001549:Benzamides; D011954:Receptors, Dopamine; D001058:Apomorphine