| Abstract: | Female rate living in groups were subjeccted to single and repeated immobllization stress (Restraint, RT). Twenty-four hours after RT, or the last RT session in the case of repeated RT, social behavior was recored in encounters with unfamilar females, matched for age and body weight. Single RT caused an increase in agonistic behavior in both its aggression and defence aspects. This was a specific effect, as other behaviors, including introductory, affiliative (Allo-Grooming), and courting items, were unifluenced by Rate The effect persisted and was even strengthened in the case of aggression, when RT was repeated once a day for 7 consecutive days. These findings, together with previous data showing a reduction in emotionality and an increase in the exploration of the physical environment following RT, suggest that in females mild stress may induce behavioral arousal, with the selective activation of specific social and non-social behavioral parameters. This contrasts with previous findings in male rats, which responded to RT with the depression of several behavioral parameters, including some of the items (aggresion, exploration) activated in females. As already found in males, in females some parameters were affected by repetition of treatment, either RT or control handing. This suggests that manipulation per se does affect social behavior. However, behavioral modifications ascribable to repeated manipulation in no way superimposed, and were clearly distinguish able from, those due to RT. © 1993 Wiley-Liss, Inc. |
