scholarly journals Antioxidant Treatment Induces Hyperactivation of the HPA Axis by Upregulating ACTH Receptor in the Adrenal and Downregulating Glucocorticoid Receptors in the Pituitary

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Jessika P. Prevatto ◽  
Rafael C. Torres ◽  
Bruno L. Diaz ◽  
Patrícia M. R. e Silva ◽  
Marco A. Martins ◽  
...  
Keyword(s):  
Vitamin E ◽  
Hpa Axis ◽  
Negative Feedback ◽  
Feedback Loop ◽  
Glucocorticoid Receptors ◽  
Plasma Corticosterone ◽  
Acth Receptor ◽  
Male Wistar Rats ◽  
Hpa Axis Activity ◽  
Nrf2 Expression

Glucocorticoid (GC) production is physiologically regulated through a negative feedback loop mediated by the GC, which appears disrupted in several pathological conditions. The inability to perform negative feedback of the hypothalamus-pituitary-adrenal (HPA) axis in several diseases is associated with an overproduction of reactive oxygen species (ROS); however, nothing is known about the effects of ROS on the functionality of the HPA axis during homeostasis. This study analyzed the putative impact of antioxidants on the HPA axis activity and GC-mediated negative feedback upon the HPA cascade. Male Wistar rats were orally treated with N-acetylcysteine (NAC) or vitamin E for 18 consecutive days. NAC-treated rats were then subjected to a daily treatment with dexamethasone, which covered the last 5 days of the antioxidant therapy. We found that NAC and vitamin E induced an increase in plasma corticosterone levels. NAC intensified MC2R and StAR expressions in the adrenal and reduced GR and MR expressions in the pituitary. NAC also prevented the dexamethasone-induced reduction in plasma corticosterone levels. Furthermore, NAC decreased HO-1 and Nrf2 expression in the pituitary. These findings show that antioxidants induce hyperactivity of the HPA axis via upregulation of MC2R expression in the adrenal and downregulation of GR and MR in the pituitary.

scholarly journals TheKampoMedicine Yokukansan Decreases MicroRNA-18 Expression and Recovers Glucocorticoid Receptors Protein Expression in the Hypothalamus of Stressed Mice

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shoko Shimizu ◽  
Takashi Tanaka ◽  
Takashi Takeda ◽  
Masaya Tohyama ◽  
Shingo Miyata
Keyword(s):  
Hpa Axis ◽  
Stress Responses ◽  
Glucocorticoid Receptors ◽  
Psychological Symptoms ◽  
Plasma Corticosterone ◽  
Mrna Levels ◽  
Stress Exposure ◽  
Protein Levels ◽  
Hpa Axis Activity ◽  
The Brain

It is well known that glucocorticoid receptor (GR) signaling regulates the hypothalamic-pituitary-adrenal (HPA) axis, and GR expression level is associated with HPA axis activity. Recent studies revealed that microRNA- (miR-) 18 and/or 124a are candidate negative regulators of GR in the brain. TheKampomedicine Yokukansan (YKS) can affect psychological symptoms such as depression and anxiety that are associated with stress responses. In this study, we evaluated the effect of YKS on miR-18 and 124a and GR levels in mice exposed to stress. We found that YKS pretreatment normalized elevated plasma corticosterone levels in stress-exposed mice. In addition, GR mRNA levels were downregulated in the brain following stress exposure. While miR-124a expression levels were not altered in the hypothalamus of stress-exposed mice, miR-18 levels decreased in the hypothalamus of YKS-pretreated mice after stress exposure. Finally, GR protein levels in the paraventricular nucleus (PVN) of the hypothalamus after stress exposure recovered in YKS-pretreated mice. Collectively, these data suggest that YKS normalizes GR protein levels by regulating miR-18 expression in the hypothalamus, thus normalizing HPA axis activity following stress exposure.

scholarly journals Behavioural and neurochemical changes induced by stress-related conditions are counteracted by the neurokinin-2 receptor antagonist saredutant

2013 ◽  
Vol 16 (4) ◽  
pp. 813-823 ◽  
Author(s):  
Alessandra Tamburella ◽  
Gian Marco Leggio ◽  
Vincenzo Micale ◽  
Andrea Navarria ◽  
Claudio Bucolo ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Hpa Axis ◽  
Forced Swim Test ◽  
Plasma Corticosterone ◽  
Bdnf Expression ◽  
Immobility Time ◽  
Male Wistar Rats ◽  
Neurochemical Changes ◽  
Nk2 Receptor ◽  
Hpa Axis Activity

Abstract These experiments were undertaken to assess the mechanisms underlying the antidepressant-like effects of the neurokinin-2 (NK2) receptor antagonist saredutant (SR48968) in rats tested in the forced swim test (FST), by analysing hippocampal brain-derived neurotrophic factor (BDNF) and plasma corticosterone [as index of hypothalamic-pituitary-adrenal (HPA) axis activity]. Male Wistar rats received three intraperitoneal injections over 24 h of vehicle, saredutant (5 mg/kg), citalopram (15 mg/kg), clomipramine (50 mg/kg). Rats were subjected to restraint stress (4 h) 24 h prior to the FST procedure. This stress procedure increased immobility and decreased swimming behaviour in the FST; furthermore, it lowered hippocampal BDNF protein expression and increased plasma corticosterone levels. Saredutant and clomipramine or citalopram, used here as positive controls, reduced the immobility time in the FST both under basal conditions and after stress exposure. This effect was not attributable to changes in locomotion, because locomotor activity was unchanged when assessed in the open field test. Pretreatment with para-cholorophenylalanine (150 mg/kg, 72 h and 48 h prior to FST) abolished the effect of citalopram and saredutant on immobility time. At neurochemical level, saredutant attenuated activation of HPA axis in stressed animals more than clomipramine or citalopram. The behavioural effects of saredutant support the hypothesis that NK2 receptor activity is involved in stress-related disorders. These effects of saredutant may be related to normalization of the HPA axis. Moreover, saredutant increases BDNF expression in the hippocampus, confirming the role of NK2 receptor blockade in BDNF activation following stressor application.

scholarly journals Disrupting Hypothalamic Glucocorticoid Receptors Causes HPA Axis Hyperactivity and Excess Adiposity

2013 ◽  
Vol 27 (10) ◽  
pp. 1655-1665 ◽  
Author(s):  
Gloria Laryea ◽  
Günther Schütz ◽  
Louis J. Muglia
Keyword(s):  
Hpa Axis ◽  
Glucocorticoid Receptors ◽  
Plasma Acth ◽  
Exon 2 ◽  
Stunted Growth ◽  
Excess Adiposity ◽  
Corticosterone Secretion ◽  
Basal Plasma ◽  
Hpa Axis Activity ◽  
Dexamethasone Suppression

The glucocorticoid receptor (GR) regulates hypothalamic-pituitary-adrenal (HPA) axis activity during the stress response. The paraventricular nucleus (PVN) is a major site of negative feedback to coordinate the degree of the HPA axis activity with the magnitude of the exposed stressor. To define the function of endogenous PVN GR, we used Cre-loxP technology to disrupt different GR exons in Sim1-expressing neurons of the hypothalamus. GR exon 2-deleted mice (Sim1Cre-GRe2Δ) demonstrated 43% loss of PVN GR compared with an 87% GR loss in exon 3-deleted mice (Sim1Cre-GRe3Δ). Sim1Cre-GRe3Δ mice display stunted growth at birth but develop obesity in adulthood and display impaired stress-induced glucose release. We observed elevated basal and stress-induced corticosterone levels in Sim1Cre-GRe3Δ mice, compared with control and Sim1Cre-GRe2Δ mice, and impaired dexamethasone suppression, indicating an inability to negatively regulate corticosterone secretion. Sim1Cre-GRe3Δ mice also showed increased CRH mRNA in the PVN, increased basal plasma ACTH levels, and reduced locomotor behavior. We observed no differences in Sim1Cre-GRe2Δ mice compared with control mice in any measure. Our behavioral data suggest that GR deletion in Sim1-expressing neurons has no effect on anxiety or despair-like behavior under basal conditions. We conclude that loss of PVN GR results in severe HPA axis hyperactivity and Cushing's syndrome-like phenotype but does not affect anxiety and despair-like behaviors.

scholarly journals Vitamin A regulates hypothalamic–pituitary–adrenal axis status in LOU/C rats

2013 ◽  
Vol 219 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Nathalie Marissal-Arvy ◽  
Rachel Hamiani ◽  
Emmanuel Richard ◽  
Marie-Pierre Moisan ◽  
Véronique Pallet
Keyword(s):  
Vitamin A ◽  
Hpa Axis ◽  
Restraint Stress ◽  
Vitamin A Deficiency ◽  
Plasma Corticosterone ◽  
Hypothalamic Pituitary Adrenal ◽  
Corticosteroid Receptors ◽  
Vitamin A Status ◽  
Corticosterone Response ◽  
Hpa Axis Activity

The aim of this study was to explore the involvement of retinoids in the hypoactivity and hyporeactivity to stress of the hypothalamic–pituitary–adrenal (HPA) axis in LOU/C rats. We measured the effects of vitamin A deficiency administered or not with retinoic acid (RA) on plasma corticosterone in standard conditions and in response to restraint stress and on hypothalamic and hippocampal expression of corticosteroid receptors, corticotropin-releasing hormone and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in LOU/C rats. Interestingly, under control conditions, we measured a higher plasma concentration of retinol in LOU/C than in Wistar rats, which could contribute to the lower basal activity of the HPA axis in LOU/C rats. Vitamin A deficiency induced an increased HPA axis activity in LOU/C rats, normalized by RA administration. Compared with LOU/C control rats, vitamin A-deficient rats showed a delayed and heightened corticosterone response to restraint stress. The expression of corticosteroid receptors was strongly decreased by vitamin A deficiency in the hippocampus, which could contribute to a less efficient feedback by corticosterone on HPA axis tone. The expression of 11β-HSD1 was increased by vitamin A deficiency in the hypothalamus (+62.5%) as in the hippocampus (+104.7%), which could lead to a higher production of corticosterone locally and contribute to alteration of the hippocampus. RA supplementation treatment restored corticosterone concentrations and 11β-HSD1 expression to control levels. The high vitamin A status of LOU/C rats could contribute to their low HPA axis activity/reactivity and to a protective effect against 11β-HSD1-mediated deleterious action on cognitive performances during ageing.

scholarly journals Maternal glucocorticoids do not influence HPA axis activity or behavior of juvenile wild North American red squirrels

2020 ◽  
Author(s):  
Sarah E Westrick ◽  
Freya van Kesteren ◽  
Stan Boutin ◽  
Jeffrey E Lane ◽  
Andrew G McAdam ◽  
...  
Keyword(s):  
Hpa Axis ◽  
Negative Feedback ◽  
North American ◽  
High Density ◽  
Early Lactation ◽  
Red Squirrels ◽  
North American Red Squirrels ◽  
And Behavior ◽  
Hpa Axis Activity ◽  
The Impact

AbstractEnvironmental factors experienced during development can affect the physiology and behavior of offspring. Maternal glucocorticoids (GCs) may convert environmental cues experienced by the mother into a cue triggering adaptive developmental plasticity in offspring. In North American red squirrels (Tamiasciurus hudsonicus), females exhibit increases in GCs when conspecific density is elevated, and selection favors more aggressive and perhaps more active mothers under high density conditions. We experimentally elevated maternal GCs during gestation or early lactation to test the hypothesis that elevated maternal GCs cause shifts in offspring aggression and activity that may prepare them for high density conditions. When offspring were weaned, we measured two behavioral traits (activity and aggression) using a standardized behavioral assay. Because maternal GCs may influence offspring hypothalamic-pituitary-adrenal (HPA) axis activity and HPA axis activity may in turn affect offspring behavior, we also measured the impact of our treatments on offspring HPA axis activity (adrenal reactivity and negative feedback) and the association between offspring HPA axis activity and behavior. Increased maternal GCs during lactation, but not gestation, only slightly elevated activity levels in offspring. Offspring aggression, adrenal reactivity, and negative feedback did not differ between GC-treated and control groups. Offspring with higher adrenal reactivity did exhibit lower aggression, but the relationship between adrenal reactivity and aggression was not affected by treatment with maternal GCs. These results suggest maternal GCs during gestation or early lactation alone may not be a sufficient cue to produce changes in behavioral and physiological stress responses in offspring in natural populations.Summary StatementWe found maternal glucocorticoid levels do not influence offspring personality or HPA axis dynamics in North American red squirrels. Regardless of maternal glucocorticoid treatment, more aggressive squirrels exhibited lower adrenal reactivity.

Disruption of mineralocorticoid receptor function increases corticosterone responding to a mild, but not moderate, psychological stressor

2005 ◽  
Vol 288 (6) ◽  
pp. E1082-E1088 ◽  
Author(s):  
Thaddeus W. W. Pace ◽  
Robert L. Spencer
Keyword(s):  
Hpa Axis ◽  
Negative Feedback ◽  
Glucocorticoid Receptors ◽  
Feedback Regulation ◽  
Sprague Dawley ◽  
Negative Feedback Regulation ◽  
Novel Environment ◽  
Sterile Saline ◽  
Sprague Dawley Rats ◽  
Psychological Stressor

Glucocorticoid negative feedback regulation of the hypothalamic-pituitary-adrenal (HPA) axis is mediated by corticosteroid receptors. It is widely thought that during stress, glucocorticoid receptors (GR) are essential for this negative feedback. In contrast, mineralocorticoid receptors (MR) are associated with HPA axis regulation in basal, nonstress conditions. Notions about the relative roles of MR and GR for HPA axis regulation during stressor challenge may not be complete. Recent work in our laboratory suggests that previous estimates of MR occupancy at resting plasma levels of corticosterone (CORT) may be overestimated. It is possible that a significant number of MR may be available to mediate negative feedback during stressor challenge. We hypothesized that this may be especially the case during mild stressor challenge when the plasma CORT response is weak. In the present studies, adult male Sprague-Dawley rats were first treated systemically or centrally with the selective MR antagonist RU28318 (50 mg/kg sc or 500 ng·10 μl−1·2 h−1 icv) or vehicle (300 μl propylene glycol sc or 10 μl/2 h sterile saline icv) and then challenged with 60-min novel environment or restraint. In vehicle controls, restraint resulted in a greater plasma CORT response than novel environment. Both systemic and central treatment with RU28318 significantly increased CORT responding to novel environment relative to vehicle controls. However, RU28318 treatment did not increase the CORT response to restraint. These data suggest that MR may be necessary for glucocorticoid regulation of HPA axis activity during mild stressors, but not during stressors that result in a more robust CORT response.

scholarly journals Effects of L-3,4-dihydroxyphenylalanine (L-Dopa) Treatment in the Neuroendocrine Response to Stress

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A67-A68
Author(s):  
Santiago Jordi Orrillo ◽  
Mercedes Imsen ◽  
Alfonsina Lizarraga ◽  
Ana Clara Romero ◽  
Fernanda De Fino ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Stress Response ◽  
Hpa Axis ◽  
Sympathetic Nerves ◽  
Serum Levels ◽  
Male Wistar Rats ◽  
Response To Stress ◽  
Behavioural Tests ◽  
Hpa Axis Activity

Abstract Stressful stimuli evoke a complex response mediated by two systems: the Sympathetic-Adreno-Medullar (SAM) axis and the Hypothalamus-Pituitary-Adrenal (HPA) axis. Among the factors involved in stress, glucocorticoids and catecholamines secreted from the adrenal glands and sympathetic nerves are the main effectors of the physiological adaptations to stressors. Besides these, prolactin (PRL) is another hormone secreted under stress conditions. Catecholamines are synthesized from the hydroxylated precursor L-Dopa. This agent is commonly used for the treatment of Parkinson’s disease and it would act as a neurotransmitter per se. On the other hand, it has been suggested that HPA axis dysregulation is a potential risk factor for the development of depression. In line with this, several studies reported that L-Dopa treatment may alter the serum levels of ACTH, PRL, and glucocorticoids in parkinsonian patients and Parkinson’s disease animal models. In the present study, we determined whether the chronic treatment with L-Dopa altered the stress response inducing depressive-like behaviours. Adult male Wistar rats were treated orally during 24 days with LEBOCAR® - commercial formulation of L-Dopa (75 mg/day) and Carbidopa (7.5 mg/day) - in drinking water. Animals were stressed by immobilization during the last 9 days of treatment and depressive-like behaviours were assessed by the sucrose intake and forced swimming tests. Behavioural tests showed no signs of depressive-like behaviours in the LEBOCAR®-treated and/or stressed rats. We next explored the SAM axis reactivity. Circulating noradrenaline and adrenaline increased in rats treated with LEBOCAR® (p<0.05; HPLC). Also, the adrenals from stressed animals showed higher content of adrenaline (p<0.05). Then, we studied the HPA axis activity. Chronically stressed rats displayed a lower ACTH secretion (ELISA) and a downregulation of POMC expression (qPCR) in the anterior pituitary (p<0.05). In addition, LEBOCAR® treatment induced a reduction in serum ACTH and POMC levels (p<0.05). As expected, serum corticosterone (ELISA) enhanced under chronic stress, an effect that was inhibited by treatment with LEBOCAR® (p<0.05). Finally, pituitary PRL gene expression (qPCR) was downregulated by LEBOCAR® treatment with a more pronounced effect when rats were also stressed (p<0.05). Our results suggest that L-Dopa alters the neuroendocrine stress response enhancing SAM axis reactivity and reducing HPA axis activity and PRL expression.

scholarly journals Postnatal Glucocorticoid Excess Due to Pituitary Glucocorticoid Receptor Deficiency: Differential Short- and Long-Term Consequences

Endocrinology ◽  
2009 ◽  
Vol 150 (6) ◽  
pp. 2709-2716 ◽  
Author(s):  
Mathias V. Schmidt ◽  
Vera Sterlemann ◽  
Klaus Wagner ◽  
Bertram Niederleitner ◽  
Karin Ganea ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Hpa Axis ◽  
Negative Feedback ◽  
Molecular Mechanisms ◽  
Forced Swim Test ◽  
Conditional Knockout ◽  
Negative Feedback Regulation ◽  
Long Term Consequences ◽  
Hpa Axis Activity

A tight regulation of hypothalamic-pituitary-adrenal (HPA) axis activity is essential for successful adaptation to stressful stimuli. Disruption of normal HPA axis development is a main risk factor for diseases such as posttraumatic stress disorder or depression, but the molecular mechanisms that lead to these long-term consequences are poorly understood. Here, we test the hypothesis that the pituitary glucocorticoid receptor (GR) is involved in regulating HPA axis function in neonatal and adult animals. Furthermore, we investigate whether postnatal hypercortisolism induced by pituitary GR deficiency is a main factor contributing to the persistent effects of early-life stress. Conditional knockout mice with a deletion of the GR at the pituitary (GRPOMCCre) show excessive basal corticosterone levels during postnatal development, but not in adulthood. The hypercortisolemic state of neonatal GRPOMCCre mice is accompanied by central gene expression changes of CRH and vasopressin in the paraventricular nucleus, but these alterations normalize at later ages. In adult mice, pituitary GR deficiency results in impaired glucocorticoid negative feedback. Furthermore, adult GRPOMCCre mice display a more active coping strategy in the forced swim test, with no alterations in anxiety like behavior or cognitive functions. Postnatal GR antagonist treatment is able to prevent the long-term behavioral effects in GRPOMCCre mice. In conclusion, we show that pituitary GRs are centrally involved in regulating HPA axis activity in neonates and mediate negative feedback regulation in adult animals. Postnatal glucocorticoid excess results in an altered stress-coping behavior in adult animals, with no effects on anxiety like behavior or cognition.

scholarly journals Future therapeutic targets in mood disorders: the glucocorticoid receptor

2000 ◽  
Vol 177 (5) ◽  
pp. 390-395 ◽  
Author(s):  
Richard McQuade ◽  
Allan H. Young
Keyword(s):  
Glucocorticoid Receptor ◽  
Mood Disorders ◽  
Hpa Axis ◽  
Negative Feedback ◽  
Clinical Studies ◽  
Glucocorticoid Receptors ◽  
Therapeutic Targets ◽  
Feedback Mechanism ◽  
Hypothalamic Pituitary Adrenal ◽  
Negative Feedback Mechanism

BackgroundThe hypercortisolaemia and dysfunction of the hypothalamic–pituitary–adrenal (HPA) axis associated with mood disorders have been attributed to a breakdown in the glucocorticoid-receptor-mediated negative feedback mechanism regulating HPA activity. Reinstating normal feedback may be therapeutic in mood disorders.AimsTo review the evidence for the involvement of the glucocorticoid receptor in the pathogenesis and treatment of mood disorders.MethodMedline and hand searches were carried out, selecting literature relevant to psychiatrists and psychopharmacologists.ResultsA dysfunction in glucocorticoid receptors is integral to the HPA abnormalities of mood disorders. Antidepressant and mood-stabilising drugs can up-regulate glucocorticoid receptors, restoring glucocorticoid function. Preliminary clinical studies targeting the glucocorticoid receptor are encouraging.ConclusionsDrugs designed specifically to up-regulate glucocorticoid receptors may be integral to future strategies in treating mood disorders.

scholarly journals Intrahypothalamic Estradiol Modulates Hypothalamus-Pituitary-Adrenal-Axis Activity in Female Rats

Endocrinology ◽  
2012 ◽  
Vol 153 (7) ◽  
pp. 3337-3344 ◽  
Author(s):  
J. Liu ◽  
P. H. Bisschop ◽  
L. Eggels ◽  
E. Foppen ◽  
E. Fliers ◽  
...  
Keyword(s):  
Hpa Axis ◽  
Restraint Stress ◽  
Acute Stress ◽  
Plasma Corticosterone ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Stress Exposure ◽  
Ici 182,780 ◽  
Hpa Axis Activity

Estrogen plays an important role in the regulation of the hypothalamus-pituitary-adrenal (HPA)-axis, but the neuroendocrine pathways and the role of estrogen receptor (ER) subtypes involved in specific aspects of this interaction remain unknown. In a first set of experiments, we administered estradiol (E2) intravenously, intracerebroventricularly, and by intrahypothalamic microdialysis to ovariectomized rats to measure plasma corticosterone (CORT) concentrations from carotid artery blood. Systemic infusion of E2 did not increase plasma CORT, but intracerebroventricular E2 induced a 3-fold CORT increase (P = 0.012). Local E2 infusions in the hypothalamic paraventricular nucleus (PVN) significantly increased plasma CORT (P < 0.001). A similar CORT increase was seen after PVN infusion of the ERα agonist propylpyrazoletriol, whereas the ERβ agonist diarylpropiolnitrile had no effect. In a second set of experiments, we investigated whether E2 modulates the HPA-axis response to acute stress by administering E2 agonists or its antagonist ICI 182,780 into the PVN during restraint stress exposure. After 30 min of stress exposure, plasma CORT had increased 5.0-fold (P < 0.001). E2 and propylpyrazoletriol administration in the PVN enhanced the stress-induced plasma CORT increase (8-fold vs. baseline), whereas ICI 182,780 and diarylpropiolnitrile reduced it, as compared with both E2 and vehicle administration in the PVN. In conclusion, central E2 modulates HPA-axis activity both in the basal state and during restraint stress. In the basal condition, the stimulation is mediated by ERα-sensitive neurons, whereas during stress, it is mediated by both ERα and ERβ.

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