• competition;
  • winner-loser;
  • anxiety;
  • animal models


Studies indicate that features such as prior stressful experience, strain, gender, and age can influence the behavior of rats in animal models of anxiety. In the present study, we examined the possible influence of competitive status (winner/loser) in three such models: the elevated plus-maze, the open field, and the social interaction test. One hundred to 135-day-old male Wistar rats were conditioned to traverse a straight runway tube to obtain food. Subsequently, two rats were placed at the same time in the runway tube and, being unable to pass each other, one of them pushed the other to the opposite end-box. The rats were categorized as winners or losers in this competition. One week after the straight runway tube test, the rats were submitted to the anxiety models, where it was observed that winner rats showed greater locomotor activity than the losers in the three models studied. Furthermore, winner rats showed less immobility and higher central and total locomotor activity in the open field and a greater duration of social interaction in the social interaction test. These results suggest that competitive status has an influence on the locomotor activity of rats in animal models of anxiety. However, whether competitive status influences anxiety as assessed in these models is unclear, and further investigations are warranted. Aggr. Behav. 28:164–171, 2002. © 2002 Wiley-Liss, Inc.