Neonatal isolation increases anxiety-like behavior in developing and adult male rats

Background and Aim : Neonate is suggested to represent a developmental period of increased vulnerability to stress due to the immaturity of adaptive processes of coping. An inability for proper adaptation to stressors during the developmental period has been proposed to contribute to psychiatric disorders in adulthood.Methods : In this study, we examined the effects of a type of early life stress; i.e. maternal separation or neonatal isolation, in which rat pups are isolated individually for 3 h per day during postnatal days (PND) 2–11 on anxiety-like behaviors in adolescence (PND 35) and adult (PND 60) male rats. Anxiety tests were conducted in an open field arena and total distance traveled and relative time spent in the center of the open field were recorded.Results : Results indicated that neonatal isolation significantly decreased time spent in the open field center in both adolescence and adult rats compared to control rats. Furthermore, adolescence and adult rats with neonatal isolation exhibited decreased activity levels in open field relative to non-handled control rats.Conclusion : These results are consistent with increased anxiety levels in both developing and adult rats exposed to neonatal isolation, and suggest that early life stress likely can cause persistent changes in controlling systems related to adaptive response to the stressors, which in turn adversely affect future social behaviors in subsequent periods of life.

کلیدواژه ها:

stress ، neonatal isolation ، anxiety ، development ، adolescence