Psychoneuroendocrinology
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Psychoneuroendocrinology · Jul 2013
Pubertal immune challenge blocks the ability of estradiol to enhance performance on cognitive tasks in adult female mice.
Puberty is a period characterized by brain reorganization that contributes to the development of neural and behavioral responses to gonadal steroids. Previously, we have shown that a single injection of the bacterial endotoxin, lipopolysaccharide (LPS; 1.5mg/kg IP), during the pubertal period (around 6weeks old) in mice decreases sexual receptivity in response to estradiol and progesterone in adulthood. These findings suggest that pubertal immune challenge has an enduring effect of decreasing the behavioral responsiveness to gonadal steroid hormones. ⋯ In contrast, in females treated with LPS at 6weeks old, estradiol failed to improve social and object memories. These results support the hypothesis that exposure to an immune challenge during puberty reduces at least some of the cognitive effects of estradiol. Moreover, these results support the idea that pubertal immune challenge compromises a wide variety of behavioral influences of ovarian hormones.
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Psychoneuroendocrinology · Jul 2013
Thyroid function tests at delivery and risk for postpartum depressive symptoms.
Postpartum depression (PPD) is a common childbirth complication, which can have negative effects on both the newly delivered woman and her family. This condition is underdiagnosed and inadequately treated, while a biological diagnostic test is not yet available. Furthermore, postpartum thyroid dysfunction is common among new mothers, and some evidence point to an association between PPD and thyroid function disturbances. ⋯ Using a binary logistic regression model (adjusting for previous psychiatric contact, smoking during pregnancy, pre-pregnancy body mass index (BMI) and sleep), having a thyroid stimulating hormone (TSH) level over the clinical cut-off level of 4.0 mU/L was associated with increased risk for depressive symptoms at six months postpartum (OR 11.30, 95% CI 1.93-66.11). A ROC analysis revealed that the predictive variable (PV) had significant predictive ability for PPD at 6 months postpartum, given that the AUC was 0.764, and at a PV cut-off value of 6.33, the sensitivity and specificity were 76.2% and 69.4%, respectively. If these findings are replicated in future studies, they can have important clinical implications, since TSH determination is an inexpensive routine blood test, and its inclusion in a biological screening test for PPD involving other parameters would be tempting.
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Psychoneuroendocrinology · Jun 2013
Neonatal amygdala lesions alter basal cortisol levels in infant rhesus monkeys.
The amygdala is mostly thought to exert an excitatory influence on the hypothalamic-pituitary-adrenal (HPA) axis, although its role regulating HPA basal tone is less clear, particularly during primate development. The current study examined the effects of neonatal amygdala lesions on basal HPA function and the postnatal testosterone (T) surge of rhesus monkeys reared with their mothers in large outdoor social groups. An early morning basal blood sample was collected at 2.5 months of age, whereas at 5 months samples were collected not only at sunrise, but also at mid-day and sunset to examine the diurnal rhythm of cortisol. ⋯ Instead, the diurnal cortisol rhythm of both males and females with amygdalectomy showed a blunted decline from mid-day to sunset compared to controls. These results indicate that neonatal amygdala damage alters basal HPA function in infant rhesus monkeys, affecting males only at early ages (at 2.5 months), while leaving the postnatal T surge intact, and resulting in a flattened diurnal rhythm in both genders at the later ages. Thus, the primate amygdala has a critical influence on the HPA axis in the first few months of life.
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Psychoneuroendocrinology · Jun 2013
Mineralocorticoid receptor antagonist spironolactone prevents chronic corticosterone induced depression-like behavior.
High level of serum corticosteroid is frequently associated with depression, in which a notable HPA (hypothalamus-pituitary-adrenal) axis hyperactivity is often observed. There are two types of corticosteroid receptors expressed in the hippocampus that provide potent negative feedback regulation on the HPA axis but dysfunction during depression, i.e. the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR). The balance between hippocampal MR and GR during chronic stress plays an important role in the occurrence of depression. ⋯ On the other hand, co-administration of MR antagonist, spironolactone (25mg/kg, i.p. × 7 days) in corticosteroid-treated animals reduced immobility time in a forced-swimming test and improved performance in a novel object recognition test. In conclusion, we demonstrate that chronic corticosterone treatment triggers several depression-like behaviors, and in parallel, down-regulates MR expression in the hippocampus and hypothalamus. Administration of an MR antagonist confers an anti-depressant effect in chronic corticosterone-treated animals.
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Psychoneuroendocrinology · Jun 2013
Effects of denial of reward through maternal contact in the neonatal period on adult hypothalamic-pituitary-adrenal axis function in the rat.
Emotional behavioral traits associated with stress response are well documented to be affected by early life events. In the present work, we used a novel paradigm of neonatal experience, in which pups were trained in a T-maze and either received (RER rats) or were denied (DER) the reward of maternal contact, during postnatal days 10-13. We then evaluated stress coping and key factors controlling the function of the hypothalamic-pituitary-adrenal axis in adulthood. ⋯ In addition, the DER neonatal experience induced an increase in hippocampal GR but a decrease in CRH-R1 immunopositive cells in the CA1 area of the hippocampus and the central amygdala. Overall, these data show a distinct stress response profile in the DER male rats, characterized by passive coping during the forced swim, increased hormonal response following stress, increased inhibitory control through GR and an indirect contribution of CRH-R1, the latter two factors resulting in a modified regulation of the response termination. It thus appears that DER rats have an enhanced potential for appropriate reactivity upon an incoming challenge, while maintaining in parallel an adequate control of the duration of their stress responses.