Anti-aggressive activity of methyl jasmonate and the probable mechanism of its action in mice.

This study examines the anti-aggressive activity of methyl jasmonate (MJ) and its probable mechanism of action in mice. Male mice that showed aggression after housing individually with female counterparts for 3 weeks or kept in isolation for 4 weeks were treated with MJ, vehicle or haloperidol (HP) 60 min before the test for aggression. Effects of p-chlorophenylalanine (PCPA) or fluoxetine (FL) given alone or in combination with MJ were also investigated. In the interaction studies, PCPA or FL was given to the animals 30 min after MJ injection and aggression testing was carried out 30 min later. Parameters assessed in the study were latency to attack, frequency of attacks, aggressive postures, lateral threats, tail rattling and pursuit frequency. MJ (1, 5, 10 mg/kg) produced a significant dose-dependent decrease in offensive aggressive behaviors. MJ did not impair the defensive mechanisms of the animals and its anti-aggressive effect was not accompanied by sedation or catalepsy. PCPA (50 mg/kg), an inhibitor of 5-hydroxytryptamine (5-HT) biosynthesis, produced a significant increase in aggressive responses and reversed the anti-aggressive effect of MJ. Additionally, FL (10 mg/kg), a 5-HT reuptake inhibitor, produced a significant suppression of aggressive behaviors and also enhanced the antiaggressive effect of MJ. Taken together, these findings suggest that methyl jasmonate exhibits specific anti-offensive aggressive activity and may be relevant in the treatment of reactive aggression in humans. Although, it appears that MJ may be affecting 5-HT(1B) receptors, additional data are needed to clearly define the mechanism(s) by which MJ exhibit antiaggressive activity. Copyright Â