RESUMO
This experiment was conducted to investigate the effects of daily pretrial intraperitoneal injection of oxytocin on behaviors of rats in an open-field situation. The group treated with 0.055 micrograms of oxytocin did not show any behavioral changes except the defecation score which was significantly more elevated than in controls. The group treated with 0.11 micrograms showed a general locomotor activity and a number of rearing behavior significantly more elevated than in all three other groups. The defecation and the grooming scores were however not different from controls. Finally, the group treated with 0.22 micrograms did not present any behavioral difference when compared with controls. Only the defecation score was significantly lower than in all the other groups. It is suggested that daily injection of oxytocin affects the arousal rather than the emotionality level.