Predictors of social instability stress effects on social interaction and anxiety in adolescent male rats

Adolescence is an important phase of development of social behaviors, which may be disrupted by the experience of stressors. We previously reported that exposure to social instability stress in adolescence (SS; postnatal day [PND] 30-45) in rats reduced social interactions with unfamiliar peers compared with non-stressed controls (CTL). In experiment 1, we replicated the effect of SS on social interaction and found that the pattern of neural activations based on Fos immunohistochemistry in brain regions during social interactions differed for SS and CTL rats. In experiment 2, we found that individual differences in novelty-seeking behavior on PND 30 and SS exposure were unique predictors of anxiety in the elevated plus maze on PND 46, and interacted to predict social interaction on PND 47; among high novelty-seeking rats, SS and CTL rats do not differ, whereas among low-novelty seeking rats, SS rats engaged in less social interaction than did CTL rats. Thus, high novelty-seeking may be a resilience factor against the effects of social stressors in adolescence.