CHANGES IN THE STRUCTURE OF THE AGONISTIC BEHAVIOR OF MICE PRODUCED BY D-AMPHETAMINE

The effects of three acute doses of D-amphetamine (0.25, 1.5 and 3 mg/ kg) were studied in a model of isolation-induced aggression in male mi ce. An ethopharmacological analysis of the encounters was carried out, which studied the frequency, total and mean duration of different beh avioral categories, including the temporal distribution of attacks and the duration of inter-attack intervals. The results show a reduction in the total and mean duration of the Attack category and an increase in motor activity manifested by longer durations, both total and mean, of Non Social Exploration and shorter Immobility. The temporal analys is of Attack revealed an increase in the number of very short (<15 s) inter-attack intervals and a temporal redistribution of the attacks to later in the course of the social encounters. These results confirm f or a complex behavior such as aggression, that D-amphetamine, even at low doses, favors a fragmentation and repetition of motor routines wit h a simultaneous reduction in the influence of environmental cues on t he control of behavior. Copyright (C) 1997 Elsevier Science Inc.