Prenatal stress induces a phase advance of circadian corticosterone rhythm in adult rats which is prevented by postnatal stress

International audiencePrenatal and postnatal stressors can have different long-term neuroendocrine effects including modifications of stress-induced corticosterone secretion. However, very little is known about the possible long-term effects of prenatal or postnatal stress on the rhythmicity of basal corticosterone secretion in adult offspring. Corticosterone levels were thus determined at six different time points over 24 h in adult rats whose mothers had undergone restraint stress manipulations. The results demonstrate that prenatal stress induces a phase advance in the evening increase of corticosterone levels, and that this change is prevented by postnatal stress. It thus appears that the circadian system governing the HPA axis is modifiable by a prenatal stress, and remains susceptible to compensatory changes during the postnatal period

Early and later adoptions differently modify mother-pup interactions

Life events occurring during the perinatal period have strong long-term effects. In rats, prenatal stress, postnatal maternal separations, or adoptions at different periods are known to affect behavior and reactivity to stress in offspring. To determine the role of maternal factors on differential outcome adoptions, the authors investigated interactions between pups and the adopting mothers by assessing both pups' ultrasound emissions and maternal behavior. Early and late adoptions increased mother care at the moment of adoption and during mother-infant reunion after a separation procedure. However, although early adoption induced a decrease in pups' ultrasound emissions in response to a stressful separation, later adoptions enhanced it. Results suggest a sensitive period during which fostering may change pups' and dams' behavior