Prenatal stress exacerbates the impact of an aversive procedure on the corticosterone response to stress in female rats.

Post-traumatic stress disorder (PTSD) is associated with marked alterations in hypothalamic-pituitary adrenal (HPA) function. In rats, prenatal restraint stress (stress applied to pregnant mothers, PRS) is known to impact behavioral and neuroendocrine sensitivity to several kinds of mild stress in adulthood. We have recently shown that PRS also modifies behavioral responses after exposure to an intense footshock in a potential animal model of PTSD. The aim of the present study was to evaluate the long-term effects of an aversive procedure (footshock followed by 3 weekly situational reminders) on the corticosterone response to a novel stress (restraint stress, 140 days after the footshock) in adult female PRS rats. Our data extend previous results showing that PRS leads to a long-lasting increase in plasma corticosterone after restraint stress in adult male rats. Moreover, we demonstrate that 140 days after the intense footshock, female PRS rats have lower corticosterone levels 60 min after restraint stress, suggesting an increase in the negative feedback of the HPA axis. These results indicate that early stress may favor long-lasting modifications of the HPA axis subsequent to exposure to an intense stress in adulthood.