Repeated neonatal separation results in different neurochemical and behavioral changes in adult male and female Mongolian gerbils

We assessed whether daily separation of Mongolian gerbils (Meriones unguiculatus) from mothers and siblings during postnatal days 4–20 would produce behavioral and neurochemical changes in adulthood that parallel some features of depression in humans. Neonatal separation altered the behavior of adult females in the open field test but not in the tail suspension test, and did not affect behavior of males. Separated males, but not females, showed a significant decrease in hippocampal brain derived neurotrophic factor (BDNF) relative to controls. Western blot and optical densitometry measurements in the hippocampus did not reveal significant group differences in synaptophysin levels in either sex, but there was a tendency toward decreased levels of synaptophysin in the entire hippocampus as well as the CA1 hippocampal subregion of separated males. Repeated separation of neonates from mothers and siblings led to subtle behavioral and neurochemical changes during adulthood that were expressed differently in male and female gerbils.