Behavioral and hormonal effects of prenatal and maternal separation stresses in postpartum rats.

The aim of this study was to evaluate the hormone and anxiety levels of rat dams who were exposed to prenatal and maternal separation stress paradigms. Sprague-Dawley rat dams were divided into Prenatal Stress (PS), Maternal Separation (MS), Prenatal Stress and Maternal Separation (PS+MS), and Control (C) groups. All animals were subjected to the open field test on the 21st postnatal day. Same-day blood samples were obtained from the tail vein in order to examine corticotrophin-releasing hormone (CRH), estradiol, oxytocin, epinephrine, norepinephrine, prolactin, progesterone, brain-derived neurotrophic factor (BDNF), endorphin, and vasopressin levels of animals via enzyme-linked immunosorbent assay (ELISA). Oxytocin levels were the highest in the control group and the lowest in the MS group. CRH levels in the MS group were significantly higher than in the PS group ( p  < .05). Intriguingly, the BDNF level was the lowest in the control and highest in the MS group. While there was a strong correlation in the CRH, vasopressin, BDNF levels in the control group, various relations were observed in the stress groups. Stressed animals exhibited several behavioral anomalies including decreased fear responses such as freezing, enhanced duration, and increased number of entries into the central zone of the open field test apparatus. PS dams exhibited reductions in estradiol and norepinephrine levels relative to control or MS dams.