Three female mice were housed with one male of the same genotype in one cage. The average time for impregnation was 1 week. After that, the male was removed from the cage. About 3 weeks later, the mated females gave birth, their pups were removed, and the postpartum female mice in each cage were divided into two groups separately, one group (stress) was subjected to 10 days of chronic unpredictable stress (CUS), which was performed as described previously [33] and consisted of eight different stressors over 10 days. There were two different stressors daily at different times of the day to prevent stress habituation. Stressors were administered as follows: two-hour restraint, 15-min tail pinch, 24-h constant light, 24-h wet bedding, 45° cage tilt, ten-minute inescapable foot shocks, 30-min elevated platform, and social isolation. The other group (control) was handled daily. In some experiments, an abbreviated (3 days) subthreshold chronic unpredictable stress was used to assess stress susceptibility in normal control and postpartum female mice [43].
