Figure 1.

Development of a model of prenatal exposure to unpredictable mild stress. (A) Experimental timeline. Pregnant females Wistar han rats (age of 8 weeks, n = 6) were exposed to an unpredictable stress protocol (consisting of strobe lights, restraint or noise), applied three times per week in a random fashion from day 3 to day 20 of pregnancy (progeny—prenatal stress group). Progeny of control group derived from age-matched female rats that were handled daily throughout pregnancy. Blood samples were collected from all pregnant dams on day 2 and day 20, and from progeny in adulthood. Different behavioral tests were conducted in young adult male and female progeny. Stereological measurements and catecholamine levels of specific brain regions were evaluated in the progeny. (B) Morning (8 am) and night (8 pm) serum corticosterone levels of control and stress-exposed prenatal stress (PS) pregnant dams were measured at the beginning of pregnancy (day 2, n = 5) and (C) at the end of pregnancy (day 20, n = 4). PS pregnant dams present a disruption in corticosterone circadian secretion at later stages of gestation. (D) Corticosterone levels of control and PS mothers were also measured after exposure to an acute stressor (restraint for 30 min; n = 4). PS mothers present significantly higher corticosterone secretion after acute stress in comparison to controls group. Error bars denote SEM. *p < 0.05, ***p < 0.001.