Noradrenergic Regulation of the Medial Prefrontal Cortex Mediates Stress Coping in Postpartum Female Mice.

The prevalence of depression in women increases during the postpartum period. We previously reported that subchronic exposure to social stress decreased passive coping in postpartum female mice. This study aimed to investigate whether noradrenaline regulation might regulate coping styles in mice. We first determined whether a different type of stress, subchronic physical stress, decreases passive coping in postpartum females. Postpartum female, virgin female, and male mice were exposed to subchronic restraint stress (restraint stress for 4 h for 5 consecutive days). Subchronic restraint stress decreased passive coping in postpartum females but not in virgin females and males in the forced swim and tail suspension tests. We next examined the neuronal mechanism by which subchronic stress decreases passive coping in postpartum female mice. Neuronal activity and expression of noradrenergic receptors in the medial prefrontal cortex (mPFC) were analyzed using immunohistochemistry and reverse transcription-quantitative polymerase chain reaction, respectively. The mPFC was manipulated using chemogenetics, knockdown, or an α