Objective: To study the role of different antidepressants on
exploration,
spontaneous motor activity and isolation induced
aggressiveness in mice, further to discuss different mechanisms of their anti aggression. Methods: With an aggressive model induced by isolation housing in mice, antagonism of different antidepressants against isolation induced aggression was evaluated. In the group housed mice given the same treatment as aggressive test,
exploration and
spontaneous motor activity were measured. Results: (1) Mianserin (0.5-5 mg·kg -1 ), buspirone (2.5-10 mg·kg -1 ) and meclobemide (2.5-10 mg·kg -1 ) significantly inhibited the exploration in the group housed mice, but not fluoxetine (2.5-10 mg·kg -1 ), imipramine (2.5-10 mg·kg -1 ) and DOI (0.5-2 mg·kg -1 ); (2) Both mianserin and buspirone, but not fluoxetine, imipramine, meclobemide and DOI, obviously reduced spontaneous motor activity; (3) Fluoxetine, mianserin, imipramine and buspirone significantly and dose dependently antagonized isolation induced aggressive behavior, whereas meclobemide failed to attenuate aggression. DOI dual regulated aggressiveness in isolation mice. Conclusion: Our findings suggest that the effects of fluoxetine, mianserin, buspirone, imipramine, meclobemide and DOI on exploration, spontaneous motor activity and isolation induced aggression in mice are different, which may involve different pharmacological mechanisms underlying their anti aggression in isolation mice. 5 HT 1A and 5 HT 2A/2C receptors may mediate isolation induced aggressive behavior in mice. The involvement of 5 HT receptor subtypes needs further clarification.