Introduction: prenatal stress have different effects on biological processes and different sections of emberyonic structures and make disorders in hypothalamo-pitutary-adrenal (HPA). In this research the
effects of prenatal stress on morphological properties of hippocampus in newborn and adult rats and their
havior in Open Field (OF) and Elevated Plus Maze (EPM) in maturity period was studied.
.Iaterial and Methods: Female pregnant Wistar rat were devided into control and experimental groups.Control pregnant females were left undisturbed in their horne cages without any stressfull conditions. In the Experimental groups, pregnant females restrained for 3 hours per day (from the 2nd weak of pregnancy until delivery). Behavioral studies were performed using Open Field (OF) and Elevated Plus Maze (EPM). Histological studies of hippocampus of new born and 2.5 month old litters were performed using Golgi and oluidin blue staining methods.
Results: Behavioral stusdies of 2.5 month aged offsprings showed that there is significant differences in orne parameters of emotional reactivities and exploratory functions. So that, in the experimental groups
e tploratory activity was diminished but emotional reactivity and anxiety were increased. Histologic studies of newborns hippocampus of adult offsprings showed significant decrease in the intensity of pyramidal and dentate gyrus fibers in experimental groups than control groups. Also the thickness of hippocampal layers were less in stress experienced newborns and adult.
Conclusion: Considering of these results and compaire with the developmental periods and structural
changes during embryonic period in rats we can have a hypothesis that following prenatal stress the normal de elopment of hippocampal cells will be delayed. These abnormalities maybe due to changes in hormonal and neurotransmitters and growth factors involving in neural cells differentiation and less myelination and
changes in glucocorticoides amounts that is effected in regulation of cell proliferation and emotional and exploratory behavioral.
