Prenatal Restraint Stress Research Articles

Prenatal stress and long-term consequences: implications of glucocorticoid hormones

We have shown that prenatal restraint stress (PNRS) induces higher levels of anxiety, greater vulnerability to drugs, a phase advance in the circadian rhythm of locomotor activity and an increase in the paradoxical sleep in adult rats. These behavioral effects result from permanent modifications to the functioning of the brain, particularly in the feedback mechanisms of the hypothalamic-pituitary–adrenal (HPA) axis: the secretion of corticosterone is prolonged after stress and the number of the central glucocorticoid receptors is reduced. These abnormalities are associated with modifications in the synthesis and/or release of certain neurotransmitters. Dysfunction of the HPA axis is due, in part, to stress-induced maternal increase of glucocorticoids, which influences fetal brain development. Some biological abnormalities in depression can be related to those found in PNRS rats reinforcing the idea of the usefulness of PNRS rats as an appropriate animal model to study new pharmacological approaches.

Depression: reduced number of granule cells in the hippocampus of female, but not male, rats due to prenatal restraint stress.

It has been hypothesized that decreased neurogenesis in the dentate gyrus may be involved in mediating depressive disorders, which are 1.5-3 times more frequent in women than in men. Additionally, prenatal stress may increase the risk of developing depression in adulthood. However, the interrelations between prenatal stress and the development of depression in adulthood, preferentially in females, are not understood. Here, we subjected pregnant rats to a single 20-min period of restraint stress on day 18 after mating. When the offspring were 75 days of age, the numbers of granule cells and pyramidal cells (area CA1-3) in the hippocampus were analyzed with the optical fractionator. The Cavalieri's principle was applied to analyze the volumes of both granule cell layer and pyramidal cell layer in the hippocampus. Prenatally stressed females, but not males, had reduced numbers of hippocampal granule cells compared to their non-prenatally stressed counterparts. This is the first report of a sex-specific difference concerning the reduction of the number of hippocampal granule cells due to prenatal stress. In humans, prenatal stress may induce cell loss in the granule cells of the hippocampus preferentially in females compared to males, and this may be a sex-specific predisposing factor for the development of depression in adulthood.

Effects of prenatal restraint stress on hypothalamic-pituitary-adrenocortical and sympatho-adrenomedullary axis in neonatal pigs

AbstractStudies in rodents and primates strongly indicate that prenatal stress affects the survival, behaviour and physiology of the offspring. Stressful stimuli during gestation may have a direct or hormone mediated effect on the development of stress systems in the foetal organism, resulting in an altered coping during stressful situations. The present study was conducted to elucidate prenatal stress effects in domestic pigs on the responses of the hypothalamicpituitary- adrenocortical (HPA) axis and the sympatho-adrenomedullary (SAM) system as well as on morbidity, mortality and growth of the offspring. Pregnant sows were subjected to a restraint stress for five minutes daily during the last five weeks of gestation. Endocrine reactions of the piglets were tested at 3, 7, 21 and 35 days of age using an immobilization test and an ACTH challenge test. Prenatally stressed piglets showed lower basal plasma cortisol and increased corticosteroid binding globulin (CBG) concentrations at 3 days of age, indicating decreased free cortisol concentrations after birth. Cortisol levels after ACTH stimulation and catecholamine levels after immobilization were not affected by the stress treatment of the sows. Piglets from stressed sows tended to have lower noradrenaline : adrenaline ratios at three days of age compared with the control piglets. In addition, stressed sows tended to have lower litter weights after birth. The morbidity and mortality during the suckling period was higher in the prenatally stressed litters, as shown by a higher frequency of diseased and perished piglets per litter. We suppose that prenatal stress during late gestation in pigs alters the development of the HPA system and impairs the vitality of the offspring.

An electron paramagnetic study of magnetic interactions in solid solutions of ferric oxide in β-Ga2 O3.

Substantial evidence has shown that the oxidative damage to hippocampal neurons is associated with the cognitive impairment induced by adverse stimuli during gestation named prenatal stress (PS). Taurine, a conditionally essential amino acid, possesses multiple roles in the brain as a neuromodulator or antioxidant. In this study, to explore the roles of taurine in PS-induced learning and memory impairment, prenatal restraint stress was set up and Morris water maze (MWM) was employed for testing the cognitive function in the one-month-old rat offspring. The mitochondrial reactive oxygen species (ROS) level，mitochondrial membrane potential (MMP), ATP and cytochrome c oxidase (CcO) activity and apoptosis-related proteins in the hippocampus were detected. The activity of the Akt-cyclic AMP response element-binding protein (CREB)-peroxisome proliferator-activated receptor–γ coactivator-1α (PGC1α) pathway in the hippocampus was measured. The results showed that high dosage of taurine administration in the early postnatal period attenuated impairment of spatial learning and memory induced by PS. Meanwhile, taurine administration diminished the increase in mitochondrial ROS, and recovered the reduction of MMP, ATP level and the activities of CcO, superoxide dismutase 2 (SOD2) and catalase induced by PS in the hippocampus. In addition, taurine administration recovered PS-suppressed SOD2 expression level. Taurine administration blocked PS-induced decrease in the ratio of Bcl-2/Bax and increase in the ratio of cleaved caspase-3/full-length caspase-3. Notably, taurine inhibited PS-decreased phosphorylation of Akt (pAkt) and phosphorylation of CREB (pCREB), which consequently enhanced the mRNA and protein levels of PGC1α. Taken together, these results suggest that high dosage of taurine administration during the early postnatal period can significantly improve the cognitive function in prenatally stressed juvenile rats via activating the Akt-CREB-PGC1α pathway. Therefore, taurine has therapeutic potential for prenatal stressed offspring rats in future.