Acute trazodone and quipazine treatment attenuates apomorphine-induced aggressive behaviour in male rats without major impact on emotional behaviour or monoamine content post mortem

Abstract

We have studied the effect of acute trazodone (3–20 mg kg−1) and quipazine (1–3 mg kg−1) treatment on the apomorphine-induced (1 mg kg−1, once daily over 2 weeks) aggressive behaviour in male Wistar rats. All doses of trazodone and quipazine tested attenuated the aggressiveness as evidenced by the abolished intensity of aggressive behaviour and increased time of latency before the first attack. The acute trazodone (3–10 mg kg−1) or quipazine (1–3 mg kg−1) treatment had no or only a minor effect on rat behaviour in the elevated plus-maze, open field, and forced swimming test. Concomitant apomorphine (1 mg kg−1) plus trazodone (3 mg kg−1), but not apomorphine (1 mg kg−1) plus quipazine (1 mg kg−1), treatment slowed the development of aggressive behaviour. Repeated apomorphine treatment moderately reduced the dopamine post mortem and increased the DOPAC and HVA contents in striatum. Other monoamines or their metabolites were unchanged. Neither trazodone and quipazine treatment nor forced swimming stress induced any changes in the monoamine contents. In conclusion, our results indicate that acute trazodone and quipazine treatment attenuates the apomorphine-induced aggressive behaviour in male rats, but this phenomenon cannot be implicated in the changes in emotional and motivational behaviour, or in changes of monoamine content post mortem.