Alterations of sex-typical microanatomy: prenatal stress modifies the structure of medial preoptic area neurons in rats.

Prenatal stress disrupts normal sexual differentiation and behavior with concomitant alterations in brain development; however, its effects on the cytoarchitecture of neurons in the sexually dimorphic medial preoptic area (mPOA) of the hypothalamus is not known. Morphometric analysis of the mPOA of adult rats showed sex differences as neurons from control females had significantly greater numbers of basal dendritic branches and cumulative basal dendritic length as compared to control male neurons. Prenatal stress significantly altered these sexual dimorphisms, as prenatally stressed (P-S) males had increased measures of cell body area, perimeter, cumulative basal dendritic length, and branch point numbers as compared to control males. Prenatal stress also altered the cytoarchitecture in the female mPOA neurons as P-S female neurons had significantly greater measures for primary dendritic branch number and a trend towards significance for several additional measures as compared to control females. Therefore, there are significant effects of both sex and prenatal stress on neuronal architecture in the mPOA that may help to explain the well-documented alterations in reproductive behaviors observed in P-S animals.