Corticotropin-releasing Hormone Receptor Antagonist Research Articles

Linear growth in children and adolescents with congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) is a relatively common disorder and one of the most challenging conditions seen by pediatric endocrinologists. Poor linear growth in CAH has been recognized for many years. There are new insights to explain this abnormality and shed light on strategies to promote normal growth. Published data suggest that the dose of hydrocortisone during two critical periods of rapid growth, namely infancy and at puberty, has a fundamental effect on growth velocity, and by definition adult height. To prevent over-treatment, hydrocortisone dosage should remain within the range of 10-15 mg/m2 body surface area per day. Precursor steroids such as 17-hydroxy progesterone (17OHP) should not be suppressed to undetectable levels. In fact, 17OHP should always be measurable, as complete suppression suggests over-treatment. CAH is a challenging disorder. High-quality compliance within the consultation setting, with the patient seeing the same specialist at every visit, will be rewarded by improved long-term growth potential. Quality auxological monitoring can avoid phases of growth suppression. New therapy with CRH receptor antagonists may lead to a more nuanced approach by allowing fine tuning of hydrocortisone replacement without the need to suppress ACTH secretion.

Stress-free blood sampling in minipigs: A novel method for assessing 24-h cortisol profiles and drug effects on diurnal and ultradian rhythms

We developed a novel, stress-free blood sampling method for minipigs, allowing continuous cortisol monitoring over 24 h. Baseline cortisol levels exhibited both ultradian and diurnal rhythms. During nighttime, smaller ultradian rhythms overlaid a lower baseline cortisol, which increased in sleeping pigs before lights were turned on. Additionally, we developed an analytical tool based on the R package “pracma” to quantify ultradian peak and circadian components of the cortisol profiles.To validate our model, we investigated the effects of Verucerfont, a CRH receptor antagonist, and Venlafaxine, a serotonin-norepinephrine reuptake inhibitor. Verucerfont reduced cortisol levels during the first 9 h without affecting diurnal rhythm. Cortisol peak parameters decreased, with a 31% reduction in overall area under the curve (AUC) and a 38% reduction in ultradian average AUC. Ultradian peaks decreased from 7 to 4.5, with 34% lower amplitude. Venlafaxine maintained plasma concentrations within the targeted human effective range.This method enables us to enhance our understanding of cortisol regulation and provide valuable insights for the impact of investigation drugs on the diurnal and ultradian rhythms of cortisol.

Pre-reproductive stress in adolescent female rats alters maternal care and DNA methylation patterns across generations

Stress during development affects maternal behavior and offspring phenotypes. Stress in adolescence is particularly consequential on brain development and maturation, and is implicated in several psychiatric disorders. We previously showed that pre-reproductive stress (PRS) in female adolescent rats affects behavior and corticotropin releasing hormone receptor 1 (CRHR1) expression in first- (F1) and second- (F2) generation offspring. We further showed that offspring phenotypes are partially reversed by post-stress treatment with fluoxetine (FLX) or the CRHR1 antagonist NBI27914 (NBI). Epigenetic processes, such as DNA methylation, are implicated in the stress response and interact with maternal care quality across generations. Here, we asked whether PRS and FLX or NBI exposure would affect maternal care and global DNA methylation in the brains of exposed dams and their adult F1 and paternally-derived F2 offspring. We found that PRS decreased self-care while increasing pup-care behaviors. PRS also increased DNA methylation in the amygdala of dams and their F1 male offspring, but decreased it in F2 females. Drug treatment had no effect on maternal care, but affected DNA methylation patterns in F0 and F1 generations. Furthermore, PRS altered the expression of DNA methylating enzymes in brain, blood and oocytes. Finally, maternal care variables differentially predicted methylation levels in PRS and control offspring. Thus, the effects of adolescent stress are long-lasting and impact methylation levels across three generations. Combined with our findings of epigenetic changes in PRS-exposed oocytes, the present data imply that biological changes and social mechanisms act in concert to influence adult offspring phenotypes.

The Nucleus Accumbens CRH-CRHR1 System Mediates Early-Life Stress-Induced Sleep Disturbance and Dendritic Atrophy in the Adult Mouse.

Adverse experiences in early life have long-lasting negative impacts on behavior and the brain in adulthood, one of which is sleep disturbance. As the corticotropin-releasing hormone (CRH)-corticotropin-releasing hormone receptor 1 (CRHR1) system and nucleus accumbens (NAc) play important roles in both stress responses and sleep-wake regulation, in this study we investigated whether the NAc CRH-CRHR1 system mediates early-life stress-induced abnormalities in sleep-wake behavior in adult mice. Using the limited nesting and bedding material paradigm from postnatal days 2 to 9, we found that early-life stress disrupted sleep-wake behaviors during adulthood, including increased wakefulness and decreased non-rapid eye movement (NREM) sleep time during the dark period and increased rapid eye movement (REM) sleep time during the light period. The stress-induced sleep disturbances were accompanied by dendritic atrophy in the NAc and both were largely reversed by daily systemic administration of the CRHR1 antagonist antalarmin during stress exposure. Importantly, Crh overexpression in the NAc reproduced the effects of early-life stress on sleep-wake behavior and NAc morphology, whereas NAc Crhr1 knockdown reversed these effects (including increased wakefulness and reduced NREM sleep in the dark period and NAc dendritic atrophy). Together, our findings demonstrate the negative influence of early-life stress on sleep architecture and the structural plasticity of the NAc, and highlight the critical role of the NAc CRH-CRHR1 system in modulating these negative outcomes evoked by early-life stress.

Emerging treatment for congenital adrenal hyperplasia.

Although the basic treatment of congenital adrenal hyperplasia (CAH) is well established, there are active clinical research projects to more closely mimic the normal diurnal rhythm of cortisol secretion and to reduce total glucocorticoid doses to minimize adverse metabolic effects. We review clinical studies on CAH treatment published in the last 18 months or currently underway according to ClinicalTrials.gov listings. These can be grouped into several broad themes: alternative dosing forms of hydrocortisone with altered pharmacokinetics or easier dose titration; corticotropin-releasing hormone receptor antagonists that reduce corticotropin (ACTH) secretion and thereby reduce adrenal androgen secretion; androgen biosynthesis inhibitors; a first clinical trial of a gene therapy vector. Alternative dosing forms of hydrocortisone are, or will shortly be, marketed, but cost may be a barrier to utilization, at least in the US market. Trials of corticotropin releasing hormone receptor antagonists and androgen biosynthesis inhibitors are currently underway. The author believes that trials of gene therapy for CAH are premature.

Hypothalamic Corticotrophin Releasing Hormone Signal Contributes to Elevated Sympathetic Outflow in primary hypertension

Corticotropin‐releasing hormone (CRH) is a neuropeptide involved in regulating neuroendocrine and autonomic function. CHR mRNA and protein expression in the hypothalamic paraventricular nucleus (PVN) are significantly increased in patients with primary hypertension. However, the role of CRH signals in elevated sympathetic outflow in primary remains unclear. Here, we showed that CRH receptor 1 (CRHR1) protein level rats was significantly increased in the PVN tissue in spontaneously hypertensive (SHR) compared with Wistar‐Kyoto (WKY). Upregulated CRHR1 level in the PVN was not significantly affected by lowing arterial blood pressure (ABP) by celiac ganglionectomy in SHRs. Immunocytochemistry staining revealed that CRHR1 immunoreactivities were in PVN neurons projecting to the rostral ventrolateral medulla (RVLM). Bath application of CRH induced a significantly greater increase in the firing rate of PVN‐RVLM projection neurons in SHRs than in WKY rats. Blocking CRHRs with astressin or CRHR1 with antalarmin significantly decreased firing rate of PVN‐RVLM projection neurons in SHR but not in WKY, while blocking CRHR2 with antisauvagine‐30 did not alter the firing rate of these neurons in SHR. Both antalarmin and antisauvagine‐30 did not change the frequency and amplitude of miniature inhibitory post‐synaptic currents or miniature excitatory post‐synaptic currents recorded in brain slice preparation of SHR and WKY rats. In addition, bilateral microinjection of CRH into the PVN produced a greater dose‐dependent increases in arterial blood pressure (ABP), renal sympathetic activity (RSNA), and heart rate (HR) in anesthetized SHRs than in WKY rats. Microinjection of CRHR1 antagonist NBI35965 into the PVN significantly reduced basal ABP, RSNA, and HR in SHRs but did not change ABP, RSNA, and HR in WKY rats. These data suggested that the upregulation of CRHR1 in the PVN is critically involved in elevated sympathetic outflow and hyperactivity of sympathetic‐related neurons in hypothalamus in primary hypertension.

Beyond depression and anxiety; a systematic review about the role of corticotropin-releasing hormone antagonists in diseases of the pelvic and abdominal organs.

Evidence for beneficial effects of corticotropin releasing hormone (CRH) antagonists in abdominal and pelvic organs is emerging in preclinical studies. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement a compilation of preclinical studies using CRH receptor antagonists as a treatment for abdominal and pelvic disease was carried out. The Animal Research: Reporting of In Vivo Experiments (ARRIVE) essential 10 guidelines were used to determine quality of the included studies. A total of 40 studies from the last 15 years studying irritable bowel syndrome, inflammatory bowel disease, endometriosis, enteritis, stress impact on gastrointestinal processes and exogenous CRH administration effects were included. Blockage of the CRH receptor 1 was mainly associated with beneficial effects while that of CRH receptor 2 worsened studied effects. However, time of administration, route of administration and the animal model used, all had an impact on the beneficial outcomes. Frequency of drugs administered indicated that astressin-2B, astressin and antalarmin were among the most utilized antagonists. Of concern, studies included were predominantly carried out in male models only, representing a gender discrepancy in preclinical studies compared to the clinical scenario. The ARRIVE score average was 13 with ~60% of the studies failing to randomize or blind the experimental units. Despite the failure to date of the CRH antagonists in moving across the clinical trials pipeline, there is evidence for their beneficial effects beyond mood disorders. Future pre-clinical studies should be tailored towards effectively predicting the clinical scenario, including reduction of bias and randomization.

Electroacupuncture alleviates anxiety and modulates amygdala CRH/CRHR1 signaling in single prolonged stress mice.

Post-traumatic stress disorder (PTSD) is an anxiety-related psychiatric disorder, manifesting high comorbidity with anxiety disorders. Its underlying neurobiological mechanisms have been associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction and stress hormones. Corticotropin-releasing hormone (CRH) is a primary stress hormone, expressed in the hypothalamus and amygdala. Electroacupuncture (EA) can improve mood disorders, but its mechanisms have not been fully elucidated. The aim of this study was to observe the effect of EA on PTSD and explore the related mechanisms. We used single prolonged stress (SPS) mice to establish a PTSD model, and EA was performed after SPS or 7 days later for a week. Then we observed their fear and anxiety-like behavior through cue-induced fear condition tests, open field test and the elevated zero maze. CRH and CRH receptor 1 (CRHR1) protein levels in the amygdala were measured in SPS mice after EA intervention. We found that EA at ST36 and GV20 improved fear and anxiety behavior in SPS mice. The amygdala CRH and CRHR1 protein levels increased in the SPS mice, and this effect was reversed by the EA intervention. CRHR1 inhibition by the CRHR1 antagonist NBI 27914 alleviated anxiety behavior in SPS mice. CRH/CRHR1 signaling in the amygdala may contribute to the anxiolytic effect of EA in SPS mice.

Hypertension in Prenatally Undernourished Young-Adult Rats Is Maintained by Tonic Reciprocal Paraventricular-Coerulear Excitatory Interactions.

Prenatally malnourished rats develop hypertension in adulthood, in part through increased α1-adrenoceptor-mediated outflow from the paraventricular nucleus (PVN) to the sympathetic system. We studied whether both α1-adrenoceptor-mediated noradrenergic excitatory pathways from the locus coeruleus (LC) to the PVN and their reciprocal excitatory CRFergic connections contribute to prenatal undernutrition-induced hypertension. For that purpose, we microinjected either α1-adrenoceptor or CRH receptor agonists and/or antagonists in the PVN or the LC, respectively. We also determined the α1-adrenoceptor density in whole hypothalamus and the expression levels of α1A-adrenoceptor mRNA in the PVN. The results showed that: (i) agonists microinjection increased systolic blood pressure and heart rate in normotensive eutrophic rats, but not in prenatally malnourished subjects; (ii) antagonists microinjection reduced hypertension and tachycardia in undernourished rats, but not in eutrophic controls; (iii) in undernourished animals, antagonist administration to one nuclei allowed the agonists recover full efficacy in the complementary nucleus, inducing hypertension and tachycardia; (iv) early undernutrition did not modify the number of α1-adrenoceptor binding sites in hypothalamus, but reduced the number of cells expressing α1A-adrenoceptor mRNA in the PVN. These results support the hypothesis that systolic pressure and heart rate are increased by tonic reciprocal paraventricular–coerulear excitatory interactions in prenatally undernourished young-adult rats.

CRH receptor antagonists from Pulsatilla chinensis prevent CRH-induced premature catagen transition in human hair follicles.

There is a growing interest in the relationship among stress hormones, neuroendocrine signaling, and skin diseases, including hair loss. Previous reports showed that stress hormones inhibit human hair growth and induce early catagen transition. Moreover, a CRH receptor antagonist reversed CRH-induced alopecia in a mouse model, suggesting that antagonization of the CRH receptor is a key clinical strategy to treat stress-induced hair loss. The aim of this study was to investigate the protective effect of CRH receptor antagonists from Pulsatilla chinensis on human hair follicles (hHFs) and human dermal papilla cells (hDPCs). hHFs were observed and scored by hair cycle. The levels of cAMP, a second messenger, were measured in each group. In addition, the mRNA and protein levels of factors related to the hair cycle were measured. Furthermore, the expression levels of various members of the mitogen-activated protein kinase (MAPK) signaling pathway related to stress were measured. CRH induced early catagen transition in an ex vivo hair organ culture model. In addition, CRH downregulated the levels of alkaline phosphatase (ALP) and hair anagen-related cytokines in cultured hDPCs. Moreover, CRH induced the phosphorylation of JNK, c-Jun, p38, ERK, and Akt in cultured hDPCs. CRH receptor antagonists isolated from Pchinensis reversed these CRH-induced modulations in both ex vivo hair follicles (HFs) and cultured hDPCs. These results indicate that Pchinensis effectively blocks CRH receptor function and that saponin derivatives from Pchinensis could be a pharmaceutical and cosmetic approach to treat stress-induced hair loss.

A CRHR1 antagonist prevents synaptic loss and memory deficits in a trauma-induced delirium-like syndrome

Older patients with severe physical trauma are at high risk of developing neuropsychiatric syndromes with global impairment of cognition, attention, and consciousness. We employed a thoracic trauma (TxT) mouse model and thoroughly analyzed age-dependent spatial and temporal posttraumatic alterations in the central nervous system. Up to 5 days after trauma, we observed a transient 50% decrease in the number of excitatory synapses specifically in hippocampal pyramidal neurons accompanied by alterations in attention and motor activity and disruption of contextual memory consolidation. In parallel, hippocampal corticotropin-releasing hormone (CRH) expression was highly upregulated, and brain-derived neurotrophic factor (BDNF) levels were significantly reduced. In vitro experiments revealed that CRH application induced neuronal autophagy with rapid lysosomal degradation of BDNF via the NF-κB pathway. The subsequent synaptic loss was rescued by BDNF as well as by specific NF-κB and CRH receptor 1 (CRHR1) antagonists. In vivo, the chronic application of a CRHR1 antagonist after TxT resulted in reversal of the observed histological, molecular, and behavioral alterations. The data suggest that neuropsychiatric syndromes (i.e., delirium) after peripheral trauma might be at least in part due to the activation of the hippocampal CRH/NF-κB/BDNF pathway, which results in a dramatic loss of synaptic contacts. The successful rescue by stress hormone receptor antagonists should encourage clinical trials focusing on trauma-induced delirium and/or other posttraumatic syndromes.

The Central Amygdala Corticotropin-releasing hormone (CRH) Neurons Modulation of Anxiety-like Behavior and Hippocampus-dependent Memory in Mice

The encoding, consolidation and retrieval of memories is a multifaceted process that depends strongly on the optimal level of arousal but high levels of arousal may trigger anxiety, which negatively impacts the memory processing by the brain. We investigated the role of CRH neurons in the central amygdala (CeA) for their capacity to modulate both, the anxiety-like behavior and hippocampus-dependent memory. First, we activated the CRH neurons in CeA using cre-dependent AAV-DREADD in CRH-cre mice. The activation of CeA CRH neurons increased the anxiety-like behavior in Elevated-O maze (O-maze) and Light-Dark box (LDB). The activation of the CeA CRH also decreased Y-maze memory performance and the discrimination index in novel object recognition test (NOR). The inhibition of CeA CRH neurons with AAV-DREADD had the opposite effects on the anxiety-like behavior and the memory tests. Next, we used a combination of retrograde cre virus injected into locus ceruleus (LC) and cre-dependent AAV-DREADD injected into the CeA. While the excitation of the CeA neurons that project to LC increased the anxiety-like behavior, it also led to a better performance on the memory tests. The behavioral and memory effects were accompanied by increased c-Fos expression in the LC region. Pretreatment with CRH1 receptor antagonist antalarmin hydrochloride blocked the effects that were observed after the activation of the CeA projections to LC. Our findings highlight the role of CeA CRH neuronal population not only as a generator of anxiety but also demonstrate their role in the control of hippocampus-dependent memory.

Icariin inhibits inflammation via immunomodulation of the cutaneous hypothalamus-pituitary-adrenal axis invitro.

Dysfunction of skin steroidogenesis plays an important role in inflammatory skin diseases. We previously carried out an animal study which showed that icariin could inhibit the inflammation of atopic dermatitis by regulating the cutaneous hypothalamus-pituitary-adrenal axis (HPAA). To explore the immunomodulation of icariin on cutaneous HPAA by detecting the response to the inflammatory cytokines tumour necrosis factor-α/interferon-γ in HaCaT cells. Cortisol level and the steroidogenesis-regulating enzymes CYP11A1 and CYP11B1 were measured to evaluate the level of skin steroidogenesis. In addition, the therapeutic effects of blocking CRH-R1 by the CRH-R1 inhibitor antalarmin and blocking the CRH-R1/2 signal pathway by the nonspecific CRH receptor antagonist astressin were observed. Unexpectedly, we found that icariin treatment blocked the secretion of the inflammatory cytokines and prevented initiation of steroidogenesis; however, prolonged treatment with icariin significantly increased steroidogenesis in HaCaT cells. The promoting effect of icariin on steroidogenesis was not dependent on the CRH-R1 pathway. Icariin has a regulatory effect on steroidogenesis in HaCaT cells, which may provide a promising therapeutic target for the treatment of inflammatory skin disorders.

Characterization of Activation of the Hypothalamic-Pituitary-Adrenal Axis by the Herbicide Atrazine in the Female Rat.

Atrazine (ATR) is a commonly used pre-emergence and early postemergence herbicide. Rats gavaged with ATR and its chlorometabolites desethylatrazine (DEA) and deisopropylatrazine (DIA) respond with a rapid and dose-dependent rise in plasma corticosterone, whereas the major chlorometabolite, diaminochlorotriazine (DACT), has little or no effect on corticosterone levels. In this study, we investigated the possible sites of ATR activation of the hypothalamic-pituitary-adrenal (HPA) axis. ATR treatment had no effect on adrenal weights but altered adrenal morphology. Hypophysectomized rats or rats under dexamethasone suppression did not respond to ATR treatment, suggesting that ATR does not directly stimulate the adrenal gland to induce corticosterone synthesis. Immortalized mouse corticotrophs (AtT-20) and primary rat pituitary cultures were treated with ATR, DEA, DIA, or DACT. None of the compounds induced an increase in ACTH secretion or potentiated ACTH release in conjunction with CRH on ACTH release. In female rats gavaged with ATR, pretreatment with the CRH receptor antagonist astressin completely blocked the ATR-induced rise in corticosterone concentrations, implicating CRH release in ATR-induced HPA activation. Intracerebroventricular infusion of ATR, DEA, and DIA but not DACT at concentrations equivalent to peak plasma concentrations after gavage dosing resulted in an elevation of plasma corticosterone concentrations. However, ATR did not induce c-Fos immunoreactivity in the paraventricular nucleus of the hypothalamus. These results indicate that ATR activates the HPA axis centrally and requires CRH receptor activation, but it does not stimulate cellular pathways associated with CRH neuronal excitation.

Stress modulates cortical excitability via α-2 adrenergic and glucocorticoid receptors: As assessed by spreading depression

An increase in cortical excitability may be one of the factors mediating stress-induced vulnerability to neuropsychiatric disorders. Since stress increases extracellular glutamate and predisposes to migraine with aura attacks, we aimed to study the effect of stress on cortical spreading depression (CSD), the biological substrate of migraine aura and a measure of cortical excitability. CSD was induced by increasing concentrations of KCl applied over the dura with 5-minute intervals and recorded from parieto-occipital cortex to assess the CSD-induction threshold in acutely-stressed, chronically-stressed and naive mice. To study the mechanisms of acute stress-induced decrease in CSD threshold, we systemically administered clonidine, yohimbine, propranolol, CRH1 receptor antagonist NBI27914, mifepristone and spironolactone at doses shown to be effective on stress as well as a central noradrenergic neurotoxin (DSP-4) before acute stress. CSD threshold was significantly lowered by acute and chronic stress as well as central noradrenergic denervation. Clonidine and mifepristone further decreased the CSD threshold below the acute stress-induced levels, whereas yohimbine reversed the acute stress-induced decrease in CSD threshold compared to the saline-injected and stressed control groups. Propranolol, NBI27914 and spironolactone did not modify the effect of acute stress on CSD threshold. Stress increases cortical excitability as illustrated by a decrease in CSD-induction threshold. This action of acute stress is mediated by α2-adrenergic and glucocorticoid receptors. The decrease in CSD threshold may account for the stress-induced susceptibility to migraine. CSD may be used as a tool to study the link between stress-related disorders and cortical excitability.

Effects of corticotropin-releasing hormone on the expression of adenosine triphosphate-sensitive potassium channels (Kir6.1/SUR2B) in human term pregnant myometrium.

ObjectiveCorticotropin-releasing hormone (CRH) is a crucial regulator of human pregnancy and parturition. Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels are important for regulating myometrial quiescence during pregnancy. We investigated regulatory effects of different concentrations of CRH on KATP channel expression in human myometrial smooth muscle cells (HSMCs) in in vitro conditions.MethodsAfter treating HSMCs with different concentrations of CRH (1, 10, 102, 103, 104 pmol/L), mRNA and protein expression of KATP channel subunits (Kir6.1 and SUR2B) was analyzed by reverse transcription-polymerase chain reaction and western blot. We investigated which CRH receptor was involved in the reaction and measured the effects of CRH on intracellular Ca2+ concentration when oxytocin was administered in HSMCs using Fluo-8 AM ester.ResultsWhen HSMCs were treated with low (1 pmol/L) and high (103, 104 pmol/L) CRH concentrations, KATP channel expression significantly increased and decreased, respectively. SUR2B mRNA expression at low and high CRH concentrations was significantly antagonized by antalarmin (CRH receptor-1 antagonist) and astressin 2b (CRH receptor-2 antagonist), respectively; however, Kir6.1 mRNA expression was not affected. After oxytocin treatment, the intracellular Ca2+ concentration in CRH-treated HSMCs was significantly lowered in low concentration of CRH (1 pmol/L), but not in high concentration of CRH (103 pmol/L), compared to control.ConclusionOur data demonstrated the regulatory effect was different when HSMCs were treated with low (early pregnancy-like) and high (labor-like) CRH concentrations and the KATP channel expression showed significant increase and decrease. This could cause inhibition and activation, respectively, of uterine muscle contraction, demonstrating opposite dual actions of CRH.

Immediate biological embedding of maltreatment in children: Berlin Longitudinal Children Study (BerlinLCS)

Stressful life events during childhood and adolescence are important risk factors for the development of psychopathologies later in life. The corticotropin releasing hormone (CRH) and the CRH receptor 1 (CRHR1) have been implicated in the link between early life adversity and adult anxiety and depression, with rodent studies identifying the very early postnatal period as highly susceptible to this programming. Here, we investigated whether stress exposure during the peripubertal period – comprising juvenility and puberty – is effective in inducing long-lasting changes in the expression of CRHR1 and CRHR2 in the hippocampus and amygdala, and whether treating animals with a CRHR1 antagonist following stress exposure could reverse behavioral alterations induced by peripuberty stress. We show that peripuberty stress leads to enhanced expression of the Crhr1, but not Crhr2, gene in the hippocampal CA1 and the central nucleus of the amygdala, in association with social deficits in the social exploration test and increased stress-coping behaviors in the forced swim test. Treatment with the CRHR1 antagonist NBI30775 (10 mg/kg) daily for 1 week (from P43 to P49), immediately following peripuberty stress exposure, prevented the occurrence of those psychopathological behaviors at adulthood. These findings highlight peripuberty as a period of plasticity for the enduring modulation of the CRHR1 system and support a growing body of data implicating the CRHR1 system in the programming effects of early life stress on eventual psychopathology. They also support recent evidence indicating that temporarily tackling CRHR1 during development might represent a therapeutic opportunity to correct behavioral trajectories linking early stress to adult psychopathology.

688. The CRH-1 Receptor Antagonist Saga in Mood and Anxiety Disorders: The Good, the Bad and the Ugly

688. The CRH-1 Receptor Antagonist Saga in Mood and Anxiety Disorders: The Good, the Bad and the Ugly

Neurokinin B Signaling in the Female Rat: a Novel Link Between Stress and Reproduction

Acute systemic stress disrupts reproductive function by inhibiting pulsatile gonadotropin secretion. The underlying mechanism involves stress-induced suppression of the GnRH pulse generator, the functional unit of which is considered to be the hypothalamic arcuate nucleus kisspeptin/neurokinin B/dynorphin A neurons. Agonists of the neurokinin B (NKB) receptor (NK3R) have been shown to suppress the GnRH pulse generator, in a dynorphin A (Dyn)-dependent fashion, under hypoestrogenic conditions, and Dyn has been well documented to mediate several stress-related central regulatory functions. We hypothesized that the NKB/Dyn signaling cascade is required for stress-induced suppression of the GnRH pulse generator. To investigate this ovariectomized rats, iv administered with Escherichia coli lipopolysaccharide (LPS) following intracerebroventricular pretreatment with NK3R or κ-opioid receptor (Dyn receptor) antagonists, were subjected to frequent blood sampling for hormone analysis. Antagonism of NK3R, but not κ-opioid receptor, blocked the suppressive effect of LPS challenge on LH pulse frequency. Neither antagonist affected LPS-induced corticosterone secretion. Hypothalamic arcuate nucleus NKB neurons project to the paraventricular nucleus, the major hypothalamic source of the stress-related neuropeptides CRH and arginine vasopressin (AVP), which have been implicated in the stress-induced suppression of the hypothalamic-pituitary-gonadal axis. A separate group of ovariectomized rats was, therefore, used to address the potential involvement of central CRH and/or AVP signaling in the suppression of LH pulsatility induced by intracerebroventricular administration of a selective NK3R agonist, senktide. Neither AVP nor CRH receptor antagonists affected the senktide-induced suppression of the LH pulse; however, antagonism of type 2 CRH receptors attenuated the accompanying elevation of corticosterone levels. These data indicate that the suppression of the GnRH pulse generator by acute systemic stress requires hypothalamic NKB/NK3R signaling and that any involvement of CRH therewith is functionally upstream of NKB.

CRHR1 links peripuberty stress with deficits in social and stress-coping behaviors

Stressful life events during childhood and adolescence are important risk factors for the development of psychopathologies later in life. The corticotropin releasing hormone (CRH) and the CRH receptor 1 (CRHR1) have been implicated in the link between early life adversity and adult anxiety and depression, with rodent studies identifying the very early postnatal period as highly susceptible to this programming. Here, we investigated whether stress exposure during the peripubertal period – comprising juvenility and puberty – is effective in inducing long-lasting changes in the expression of CRHR1 and CRHR2 in the hippocampus and amygdala, and whether treating animals with a CRHR1 antagonist following stress exposure could reverse behavioral alterations induced by peripuberty stress. We show that peripuberty stress leads to enhanced expression of the Crhr1, but not Crhr2, gene in the hippocampal CA1 and the central nucleus of the amygdala, in association with social deficits in the social exploration test and increased stress-coping behaviors in the forced swim test. Treatment with the CRHR1 antagonist NBI30775 (10 mg/kg) daily for 1 week (from P43 to P49), immediately following peripuberty stress exposure, prevented the occurrence of those psychopathological behaviors at adulthood. These findings highlight peripuberty as a period of plasticity for the enduring modulation of the CRHR1 system and support a growing body of data implicating the CRHR1 system in the programming effects of early life stress on eventual psychopathology. They also support recent evidence indicating that temporarily tackling CRHR1 during development might represent a therapeutic opportunity to correct behavioral trajectories linking early stress to adult psychopathology.