Prenatal stress affects behavioral reactivity to an intense stress in adult female rats

Abstract

In rats, prenatal stress has been shown to influence behavioral and neuroendocrinological immediate responsivity to several kinds of mild stress in adulthood. Indeed, prenatal stress increases anxiety-like behavior, depressive-like disturbances and alters the hypothalamo-pituitary–adrenal (HPA) axis response to stress. However, long-term effects of an intense stress on behavior of prenatally stressed rats remain unknown. Moreover, most studies focus on male offspring. The aim of our study was to evaluate long-term behavioral effects of an aversive procedure consisting of an intense footshock (2 mA, 10 s) followed by three weekly situational reminders in prenatally stressed female rats. Prenatal stress was achieved by restraining the pregnant dams under bright light three times per day for 45 min during the last week of pregnancy. The aversive procedure induced long-term behavioral alterations in adult animals: an increase of immobility in the footshock chamber, hypoactivity in a novel environment and decreased avoidance of an “aversive-like” context. Interestingly, the procedure induced opposite effects in control and prenatally stressed females, suggesting bi-directional manifestation in some situations. In conclusion, prenatal stress affects behavioral response to an intense footshock associated with repeated situational reminders. These results suggest that early stress may interact with later ability to cope with intense stress in adulthood.