Behavioral profile of amisulpride in agonistic encounters between male mice

Amisulpride is a substituted benzamide derivative that acts as a selective dopamine D2/D3 receptor antagonist. Although the anti-aggressive properties of neuroleptic drugs are well known, the effects of amisulpride on agonist ic interactions have not been explored, and there are no studies comparing acute and subchronic effects of this compound on aggression in rodents. In this study, we examined the action of amisulpride (5-25 mg/kg, i.p), admini stered acutely or subchronically for 10 days, on agonistic behavior elicite d by isolation in male mice. Individually housed mice were exposed to anosm ic "standard opponents" 30 min after drug administration, and the encounter s were videotaped and evaluated using an ethologically based analysis. Afte r acute treatment, amisulpride (5-20 mg/kg) exhibited an ethopharmacologica l profile characterized by a marked decrease of offensive behaviors (threat and attack) without an impairment of motor activity. By contrast, the anti -aggressive action of the highest dose used (25 mg/kg) was accompanied by a weak increase of immobility. Body care was also significantly enhanced aft er treatment with the drug (20 and 25 mg/kg), emphasizing the involvement o f dopaminergic receptors in this behavior. After subchronic treatment, no t olerance to amisulpride anti-aggressive activity was observed. Overall, thi s behavioral profile is similar to that observed by other atypical neurolep tics. (C) 1999 Wiley-Liss, Inc.