CRH Expression Research Articles

Does repeated anticipation induce neuroendocrine modulation of the immune system in domestic pigs?

To improve animal welfare in pig husbandry it is necessary to expand our knowledge of affective states and their physiological effects. In our study, we used a controlled setup to induce affective states and neuroendocrine immune modulation. For each trial, six female piglets were being housed in individual pens in the same room. Three of these piglets were conditioned six times a day to a sound that was followed by a positive stimulus (food), a negative stimulus (air-puff) or a random choice of food or air-puff. This was supposed to induce positive, negative or conflicting anticipation, respectively. The other three piglets obtained positive, negative or no stimuli without conditioning and served as controls. Within four weeks, we expected changes in mood and consequently physiological effects. Preliminary analyses showed an increase in heart rate and heart rate variability in positively anticipating pigs during the sound reflecting an activation of the sympathetic nervous system. These animals also showed an increased serotonin turnover in the ventral tegmental area and a significant decrease in SEB-induced T-cell proliferation. The immunoglobulin production showed an age-dependent increase which was less pronounced for IgM of positively anticipating pigs. While plasma ACTH and salivary cortisol concentrations decreased during the experiment indicating adaptation, there were no treatment-induced effects and in line with this no differences in CRH and GR gene expression in the brain. Our data indicate that a supposedly positive anticipation may be accompanied by a frequent arousal of the pigs with a potentially negative influence on immunocompetence.

Estrogen-related receptor β deficiency alters body composition and response to restraint stress

BackgroundEstrogen-related receptors (ERRs) are orphan nuclear hormone receptors expressed in metabolically active tissues and modulate numerous homeostatic processes. ERRs do not bind the ligand estrogen, but they are able to bind the estrogen response element (ERE) embedded within the ERR response elements (ERREs) to regulate transcription of genes. Previous work has demonstrated that adult mice lacking Errβ have altered metabolism and meal patterns. To further understand the biological role of Errβ, we characterized the stress response of mice deficient for one or both alleles of Errβ.ResultsSox2-Cre:Errβ mice lack Errβ expression in all tissues of the developing embryo. Sox2-Cre:Errβ+/lox heterozygotes were obese, had increased Npy and Agrp gene expression in the arcuate nucleus of the hypothalamus, and secreted more corticosterone in response to stress. In contrast, Sox2-Cre:Errβlox/lox homozygotes were lean and, despite increased Npy and Agrp gene expression, did not secrete more corticosterone in response to stress. Sox2-Cre:Errβ+/lox and Sox2-Cre:Errβlox/lox mice treated with the Errβ and Errγ agonist DY131 demonstrated increased corticotropin-releasing hormone (Crh) expression in the paraventricular nucleus of the hypothalamus, although corticosterone levels were not affected. Nes-Cre:Errβlox/lox mice, which selectively lack Errβ expression in the nervous system, also demonstrated elevated stress response during an acoustic startle response test and decreased expression of both Crh and corticotropin-releasing hormone receptor 2 (Crhr2).ConclusionsLoss of Errβ affects body composition, neuropeptide levels, stress hormones, and centrally-modulated startle responses of mice. These results indicate that Errβ alters the function of the hypothalamic-pituitary-adrenocortical axis and indicates a role for Errβ in regulating stress response.

Intact Catecholamine Inputs to the Forebrain are Required for Appropriate Regulation of Corticotrophin‐Releasing Hormone and Vasopressin Gene Expression by Corticosterone in the Rat Paraventricular Nucleus

Corticotrophin-releasing hormone (CRH) neuroendocrine neurones in the paraventricular nucleus of the hypothalamus (PVH) drive adrenocorticotrophic hormone (ACTH) and thereby glucocorticoid release from pituitary corticotrophs and the adrenal cortex, respectively. Glucocorticoids suppress the ability of neuroendocrine corticotrophin-releasing hormone (CRH) neurones to synthesise and release ACTH secretogogues. Despite the importance of glucocorticoids as regulatory signals to CRH neurones in the extended time domain, how and where they act in this capacity is still not fully understood. Ascending catecholamine projections encode important cardiovascular, metabolic and other visceral information to the rat PVH and surrounding hypothalamus. These afferents have previously been implicated as targets for glucocorticoid action, including a role in the feedback regulation of PVH neuroendocrine neurones. To determine the contribution of these neurones to the long-term actions of corticosterone on CRH and vasopressin (AVP) gene expression in the PVH, we used an immunocytotoxin (a conjugate of the cytotoxin saporin and an antibody against dopamine-β-hydroxylase) that specifically ablates adrenergic and noradrenergic neurones. Lesions were administered to intact animals and to adrenalectomised animals with either no corticosterone or corticosterone replacement that provided levels above those required to normalise Crh expression. The ability of elevated levels of corticosterone to suppress Crh expression was abolished in animals lacking catecholaminergic innervation of the PVH. No effect was seen in the absence of corticosterone or in animals with intact adrenals. Furthermore, Avp expression, which is increased in CRH neurones following adrenalectomy, was suppressed in adrenalectomised catecholaminergic-lesioned animals. Interactions between corticosterone and catecholaminergic projections to the hypothalamus therefore make significant contributions to the regulation of Crh and Avp expression. However, the importance of catecholamine inputs is only apparent when circulating corticosterone concentrations are maintained either below or above those required to maintain the activity of the hypothalamic-pituitary-adrenal axis that is seen in intact animals.

S6K1 in the Central Nervous System Regulates Energy Expenditure via MC4R/CRH Pathways in Response to Deprivation of an Essential Amino Acid

It is well established that the central nervous system (CNS), especially the hypothalamus, plays an important role in regulating energy homeostasis and lipid metabolism. We have previously shown that hypothalamic corticotropin-releasing hormone (CRH) is critical for stimulating fat loss in response to dietary leucine deprivation. The molecular mechanisms underlying the CNS regulation of leucine deprivation–stimulated fat loss are, however, still largely unknown. Here, we used intracerebroventricular injection of adenoviral vectors to identify a novel role for hypothalamic p70 S6 kinase 1 (S6K1), a major downstream effector of the kinase mammalian target of rapamycin, in leucine deprivation stimulation of energy expenditure. Furthermore, we show that the effect of hypothalamic S6K1 is mediated by modulation of Crh expression in a melanocortin-4 receptor–dependent manner. Taken together, our studies provide a new perspective for understanding the regulation of energy expenditure by the CNS and the importance of cross-talk between nutritional control and regulation of endocrine signals.

Crh and Oprm1 mediate anxiety-related behavior and social approach in a mouse model of MECP2 duplication syndrome

Genomic duplications spanning Xq28 are associated with a spectrum of phenotypes including anxiety and autism. The minimal region shared among affected individuals includes MECP2 and IRAK1, however, it is unclear which gene, when overexpressed, causes anxiety and social behavior deficits. We report that doubling MeCP2 levels causes heightened anxiety and autism-like features in mice, and alters the expression of genes that influence anxiety and social behavior, such as Crh and Oprm1. To test the hypothesis that alterations in these two genes contribute to the heightened anxiety and social behavior deficits, we analyzed MECP2 duplication mice (MECP2-TG1) with reduced Crh and Oprm1 levels. In MECP2-TG1 animals, reducing Crh, or its receptor, Crhr1, suppresses anxiety-like behavior; in contrast, reducing Oprm1 improves abnormal social behavior. These data demonstrate that increased MeCP2 levels impact molecular pathways underlying anxiety and social behavior, and provide novel insight into potential therapies for MECP2-related disorders.

Genistein upregulates placental corticotropin-releasing hormone expression in lipopolysaccharide-sensitized mice

Genistein is a phytoestrogen isolated from soyabeans. Although soy products are staple food of Asian, the potential effect of genistein on reproduction has not been fully addressed. Lipopolysaccharide (LPS) is an endotoxin found in the cell membrane of gram-negative bacteria. It may cause inflammation and other immune responses. Previous study has shown that LPS may induce pre-mature birth in rodents. In the present study, effect of genistein on LPS-induced preterm birth was investigated. Pregnant ICR mice were gavaged with genistein at 40, 200 and 400 mg/kg body weight/day during E13 to E16. LPS was injected i.p. on E16.5 and the animals were sacrificed at E17. Compared to the control group, an increased incidence of early delivery was observed in the pooled mice under LPS treatment. A rising trend of incidence was also demonstrated dose-dependently with genistein co-treatment. Real-time RT-PCR indicated that the placental crh expression was highly induced by the co-administration of 400 mg/kg genistein and LPS. By contrast, neither genistein nor LPS alone could alter the expression. Increased plasma CRH concentration was also seen in the co-treatment groups. In addition, the mRNA expression of placental CRH-binding protein and plasma progesterone concentration were reduced in these groups. These results indicated that genistein might exacerbate the undesirable effect of LPS on pregnant mice by altering hormonal regulations.

Persistent expression of activated Notch inhibits corticotrope and melanotrope differentiation and results in dysfunction of the HPA axis

The hypothalamic-pituitary-adrenal (HPA) axis is an important regulator of energy balance, immune function and the body's response to stress. Signaling networks governing the initial specification of corticotropes, a major component of this axis, are not fully understood. Loss of function studies indicate that Notch signaling may be necessary to repress premature differentiation of corticotropes and to promote proliferation of pituitary progenitors. To elucidate whether Notch signaling must be suppressed in order for corticotrope differentiation to proceed and whether Notch signaling is sufficient to promote corticotrope proliferation, we examined the effects of persistent Notch expression in Pomc lineage cells. We show that constitutive activation of the Notch cascade inhibits the differentiation of both corticotropes and melanotropes and results in the suppression of transcription factors required for Pomc expression. Furthermore, persistent Notch signaling traps cells in the intermediate lobe of the pituitary in a progenitor state, but has no effect on pituitary proliferation. Undifferentiated cells are eliminated in the first two postnatal weeks in these mice, resulting in a modest increase in CRH expression in the paraventricular nucleus, hypoplastic adrenal glands and decreased stress-induced corticosterone levels. Taken together, these findings show that Notch signaling is sufficient to prevent corticotrope and melanotrope differentiation, resulting in dysregulation of the HPA axis.

Leucine Deprivation Stimulates Fat Loss via Increasing CRH Expression in the Hypothalamus and Activating The Sympathetic Nervous System

We previously showed that leucine deprivation decreases abdominal fat mass largely by increasing energy expenditure, as demonstrated by increased lipolysis in white adipose tissue (WAT) and uncoupling protein 1 (UCP1) expression in brown adipose tissue (BAT). The goal of the present study was to investigate the possible involvement of central nervous system (CNS) in this regulation and elucidate underlying molecular mechanisms. For this purpose, levels of genes and proteins related to lipolysis in WAT and UCP1 expression in BAT were analyzed in wild-type mice after intracerebroventricular administration of leucine or corticotrophin-releasing hormone antibodies, or in mice deleted for three β-adrenergic receptors, after being maintained on a leucine-deficient diet for 7 d. Here, we show that intracerebroventricular administration of leucine significantly attenuates abdominal fat loss and blocks activation of hormone sensitive lipase in WAT and induction of UCP1 in BAT in leucine-deprived mice. Furthermore, we provide evidence that leucine deprivation stimulates fat loss by increasing expression of corticotrophin-releasing hormone in the hypothalamus via activation of stimulatory G protein/cAMP/protein kinase A/cAMP response element-binding protein pathway. Finally, we show that the effect of leucine deprivation on fat loss is mediated by activation of the sympathetic nervous system. These results suggest that CNS plays an important role in regulating fat loss under leucine deprivation and thereby provide novel and important insights concerning the importance of CNS leucine in the regulation of energy homeostasis.

Angiotensin II Type 1 Receptor Signaling Regulates Feeding Behavior through Anorexigenic Corticotropin-releasing Hormone in Hypothalamus

The activation of renin-angiotensin system contributes to the development of metabolic syndrome and diabetes as well as hypertension. However, it remains undetermined how renin-angiotensin system is implicated in feeding behavior. Here, we show that angiotensin II type 1 (AT(1)) receptor signaling regulates the hypothalamic neurocircuit that is involved in the control of food intake. Compared with wild-type Agtr1a(+/+) mice, AT(1) receptor knock-out (Agtr1a(-/-)) mice were hyperphagic and obese with increased adiposity on an ad libitum diet, whereas Agtr1a(-/-) mice were lean with decreased adiposity on a pair-fed diet. In the hypothalamus, mRNA levels of anorexigenic neuropeptide corticotropin-releasing hormone (Crh) were lower in Agtr1a(-/-) mice than in Agtr1a(+/+) mice both on an ad libitum and pair-fed diet. Furthermore, intracerebroventricular administration of CRH suppressed food intake both in Agtr1a(+/+) and Agtr1a(-/-) mice. In addition, the Crh gene promoter was significantly transactivated via the cAMP-responsive element by angiotensin II stimulation. These results thus demonstrate that central AT(1) receptor signaling plays a homeostatic role in the regulation of food intake by maintaining gene expression of Crh in hypothalamus and suggest a therapeutic potential of central AT(1) receptor blockade in feeding disorders.

Colitis-Associated Adipose Tissue Responses to Corticotropin-Releasing Hormone Family of Neuropeptides

Background and Aims: Numerous studies have indicated that adipose tissue is an active endocrine organ and several adipose-associated molecules have been implicated as potential mediators of intestinal inflammation. Results from our group and others indicate that corticotrophin releasing hormone (CRH or CRF), and its peptide family members urocortins (UCNs) participate in the pathophysiology of intestinal inflammation and inflammatory bowel disease (IBD). Recent evidence also indicates that CRH receptors 1 and 2 are expressed by human adipocytes. Whether these ligands and receptors are expressed in the mesenteric fat and are modulated during colitis has never been studied. Here we compared levels of expression of the CRH peptide family at in the mesenteric fat depots of mice before and after experimental TNBS-induced colitis. We also exposed isolated human mesenteric preadipocytes to CRH and measured changes in cytokine production at the mRNA and protein levels. Methods: C57BL6 mice (n=10 per group) were injected intracolonically with either vehicle (40% ethanol, control) or TNBS (5 mg/20 grams) for 48 hr. Mesenteric adipose tissue was harvested from the mice and mRNA was isolated and converted to cDNA for real time RT PCR. Human mesenteric pre-adipocytes grown in culture were stimulated with 100nM CRH for 8 hours. Supernatants were collected for protein array and ELISA while mRNA was isolated for conversion to cDNA and use in real time RT PCR experiments. Data were analyzed using a two tailedMannWhitney test. Results: CRHmRNAwas significantly increased inmesenteric fat of TNBS-exposed mice compared to controls (by 112.9 fold, p<0.01). UCNs 2 and 3 were also significantly increased in these tissues (by 30.7 and 9.2 fold, p< 0.0016 and p< 0.0052, respectively). Protein arrays on CRH stimulated human mesenteric preadipocytes showed increased secretion of TIMP-2 and Rantes (CCL5 gene product) and decreased MIF, MCP-3 and PAI-1 levels. Changes in released MIF were also confirmed by ELISA in the medium of preadipocytes (p< 0.01). Conclusions: Increased expression of CRH and urocortins in adipose tissue during colitis together with the ability of CRH to induce changes in cytokine release from isolated adipocytes suggest that the CRH family of peptides may mediate inflammatory responses in mesenteric fat and affect the development of intestinal inflammation. These findings may represent a novel signaling pathway in colitis and could have important implications for inflammatory bowel disease treatment targets. Research Support: NIH NIDDK T32 DK07180-36 Gastroenterology Training Grant and P01 DK 33506

Histone deacetylase 1 (HDAC1) participates in the down-regulation of corticotropin releasing hormone gene ( crh) expression

The paraventricular nucleus of the hypothalamus (PVH) plays a central role in regulating the hypothalamic-pituitary-adrenal (HPA) axis. Medial parvocellular neurons of the PVH (mpPVH) integrate sensory and humoral inputs to maintain homeostasis. Humoral inputs include glucocorticoids secreted by the adrenals, which down-regulate HPA activation. A primary glucocorticoid target is the population of mpPVH neurons that synthesize and secrete corticotropin-releasing factors, the most potent of which is corticotropin-releasing hormone (CRH). Although CRH gene ( crh) expression is known to be down-regulated by glucocorticoids, the mechanisms by which this process occurs are still poorly understood. To begin this study we postulated that glucocorticoid repression of crh involves HDAC recruitment to the region of the crh proximal promoter. To evaluate this hypothesis, we treated hypothalamic cells that express CRH with the HDAC inhibitor trichostatin A (TSA). As predicted, treatment with TSA led to increased CRH mRNA levels and crh promoter activity. Although co-treatment with Dex (10 −7 M) reduced the TSA effect on mRNA levels, it failed to reduce promoter activity; however co-transfection of HDAC1 but not 3 restored Dex inhibition. A distinction between HDAC1 and 3 was also apparent with respect to crh promoter occupancy. Dex led to increased HDAC1 but not HDAC3 occupancy. In vivo studies revealed that CRH-immunoreactive (-ir) neurons contained HDAC1- and HDAC3-ir. Collectively, these data point to a role for HDAC1 in the physiologic regulation of crh.

Impaired CRH and Urocortin Expression and Function in Eutopic Endometrium of Women with Endometriosis

Women with endometriosis have altered endometrial function. CRH and urocortin (Ucn) are neuropeptides produced by human endometrium and modulate endometrial decidualization. To evaluate endometrial mRNA expression of CRH and Ucn, their role in in vitro decidualization of cultured human endometrial stromal cells (HESCs) in patients with endometriosis, and the role of CRH receptors (CHR-Rs). Obstetrics and Gynecology, University of Siena. Endometrial specimens were obtained from patients with and without endometriosis. Endometrial biopsy obtained at both phases of menstrual cycle. In vitro decidualization of HESCs collected from endometriosis or control was done in the presence of CRH, Ucn, or CRH receptor type 1 (CRH-R1, antalarmin) or type 2 (CRH-R2, astressin 2b) antagonists. Endometrial mRNA expression of CRH and Ucn during endometrial cycle; prolactin, CRH-R1, and CRH-R2 mRNA expression during in vitro decidualization. In healthy women CRH and Ucn expression were significantly higher (P < 0.05) in secretory than in proliferative phase; no differences were observed in endometriotic women. During in vitro decidualization, prolactin mRNA expression and release in endometriosis was lower than in control (P < 0.001). CRH and Ucn were able to significantly increase (P < 0.01) prolactin release only in control group; moreover, in this group antalarmin reduced prolactin release (P < 0.01). CRH-R1 mRNA expression increased during in vitro decidualization of HESCs in control (P < 0.01) but not in endometriosis. Women with endometriosis show an impaired endometrial expression of CRH and Ucn mRNA, and these neuropeptides are no more active in modulating the in vitro decidualization of HESCs, associated with a reduced expression of CRH-R1 mRNA.

Differential Changes in Expression of Metabolic-related Neuropeptides in the Rat Brain during Morphine Withdrawal-induced Anorexia

Event Abstract Back to Event Differential Changes in Expression of Metabolic-related Neuropeptides in the Rat Brain during Morphine Withdrawal-induced Anorexia B. Pintér-Kübler1, S. Ferenczi1, A. Molnár1, C. Núñez2, Z. Szőke1, M. V. Milanés2 and K. J. Kovács1* 1 Institute of Experimental Medicine, Hungary 2 University of Murcia, Spain In this study we followed the effects of chronic morphine exposure and naloxone-precipitated morphine withdrawal on energy balance, metabolic related hormone secretion as well as on the transcription of anorexigenic and orexigenic neuropeptides within the hypothalamus. Animals were implanted with morphine pellets and on day 8, morphine withdrawal was precipitated by an injection of naloxone. Rats were decapitated at various time intervals after injection. Food consumption and the body weight change were recorded daily. Morphine treated animals consumed significantly less food than placebo implanted controls and it was accompanied by a reduction in body weight gain. Morphine withdrawal resulted in elevation of CRH and UCNII expression and a decline in POMC levels. The relative quantity of POMC and CART mRNAs in the hypothalamic samples gradually decrease, while NPY expression is only transiently upregulated. Morphine withdrawal results in serious affective and somatic symptoms including activation of the hypothalamo-pituitary-adrenocortical (HPA) axis. The plasma levels of ACTH were increased and lasted up to 2 hours after administration of naloxone.The present data suggest a possible role of hypothalamic CRH and UCNII,- rather than POMC/CART system in mediation of metabolic changes such as weight loss during naloxone precipitated morphine withdrawal in rats. Keywords: Behaviour and cognition, Neuroscience Conference: 13th Conference of the Hungarian Neuroscience Society (MITT), Budapest, Hungary, 20 Jan - 22 Jan, 2011. Presentation Type: Abstract Topic: Behaviour and cognition Citation: Pintér-Kübler B, Ferenczi S, Molnár A, Núñez C, Szőke Z, Milanés MV and Kovács KJ (2011). Differential Changes in Expression of Metabolic-related Neuropeptides in the Rat Brain during Morphine Withdrawal-induced Anorexia. Front. Neurosci. Conference Abstract: 13th Conference of the Hungarian Neuroscience Society (MITT). doi: 10.3389/conf.fnins.2011.84.00021 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 03 Mar 2011; Published Online: 23 Mar 2011. * Correspondence: Dr. K. J Kovács, Institute of Experimental Medicine, Budapest, Hungary, kovacs@koki.hu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers B. Pintér-Kübler S. Ferenczi A. Molnár C. Núñez Z. Szőke M. V Milanés K. J Kovács Google B. Pintér-Kübler S. Ferenczi A. Molnár C. Núñez Z. Szőke M. V Milanés K. J Kovács Google Scholar B. Pintér-Kübler S. Ferenczi A. Molnár C. Núñez Z. Szőke M. V Milanés K. J Kovács PubMed B. Pintér-Kübler S. Ferenczi A. Molnár C. Núñez Z. Szőke M. V Milanés K. J Kovács Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Functional Hypothalamic Amenorrhea Due to Increased CRH Tone in Melanocortin Receptor 2-Deficient Mice

Exposure to chronic stressors results in dysregulation of the hypothalamic-pituitary-adrenal axis and a disruption in reproduction. CRH, the principal regulator of the hypothalamic-pituitary-adrenal axis induces the secretion of ACTH from the pituitary, which stimulates adrenal steroidogenesis via the specific cell-surface melanocortin 2 receptor (MC2R). Previously, we demonstrated that MC2R(-/-) mice had undetectable levels of corticosterone despite high ACTH levels. Here, we evaluated the reproductive functions of female MC2R(-/-) mice and analyzed the mechanism of the disrupted cyclicity of these mice. The expression of CRH in the paraventricular nucleus was significantly increased in MC2R(-/-) mice under nonstressed conditions. Although MC2R(-/-) females were fertile, they showed a prolonged estrous cycle. After hormonal stimulation, MC2R(-/-) females produced nearly-normal numbers of eggs, but slightly less than MC2R(+/-) females, and showed near-normal ovarian histology. During diestrus, the number of GnRH-positive cells in the medial preoptic area was significantly reduced in MC2R(-/-) females. CRH type 1 receptor antagonist restored estrous cyclicity in MC2R(-/-) females. Kisspeptin-positive areas in the arcuate nucleus were comparable, whereas kisspeptin-positive areas in the anteroventral periventricular nucleus in MC2R(-/-) females were significantly reduced compared with MC2R(+/-) females, suggesting that arcuate nucleus kisspeptin is not involved, but anteroventral periventricular nucleus kisspeptin may be involved, in the maintenance of estrous cyclicity. Our findings show that high levels of hypothalamic CRH disturb estrous cyclicity in the female animals and that the MC2R(-/-) female is a unique animal model of functional hypothalamic amenorrhea.

Sepsis – Die Bedeutung der neuroendokrinen Achse in der Pathophysiologie der Sepsis

The immune system and the central nervous system are able to affect each other. Proinflammatory cytokines induce the expression of CRH or AVP in the hypothalamus and ACTH in the pituitary gland. Thus, enhanced adrenal release of cortisol suppresses the activation of NF-κB and activates antiinflammatory cytokines. The cholinergic antiinflammatory pathway, the efferent arm of the inflammatory reflex, is another mechanism of the CNS to control inflammation. It consists of the efferent vagus nerve, the neurotransmitter actylcholine and the α7 subunit of the nicotinic acteylcholine receptor. Probably, the transmission of information takes place to postsynaptic sympathetic fibres in the celiac plexus which terminate in the spleen and act on splenic immune cells. Cholinesterase inhibitors have antiinflammatory effects in experimental sepsis when administered early.

Comparison of feeding suppression by the anorexigenic hormones neuromedin U and neuromedin S in rats

We compared the central mechanisms of feeding suppression by the anorexigenic hormones neuromedin U (NMU) and neuromedin S (NMS) in rats. I.c.v. injection of either NMU or NMS dose dependently decreased 3-h food intake during the first quarter of a dark period. Pretreatment involving i.c.v. injection of a specific anti-NMS IgG blocked the suppression of food intake induced by i.c.v.- and i.p.-injected leptin, but anti-NMU IgG elicited no blockade. Quantitative PCR analysis revealed that i.c.v. injection of NMU or NMS caused a dose-dependent increase in CRH and proopiomelanocortin mRNA expression in the paraventricular nucleus (PVN) and arcuate nucleus (Arc) respectively. In tissue cultures of the Arc, secretion of α-melanocyte-stimulating hormone was stimulated by NMU and NMS, with more potent stimulation by NMS. The time-course curves of the increase in neuronal firing rate in Arc slices in response to NMU and NMS showed almost the same pattern, with a peak 10-15 min after treatment, whereas the time-course curves for the PVN slices differed between NMU and NMS. These results suggest that NMS and NMU may share anorexigenic effects, depending on physiological conditions.

Modulation of the CRH system by substance P/NKA in an animal model of depression

It has been suggested by studies in animals and humans that substance P (SP) and its receptor neurokinin 1 (NK1R) play an important role in the pathology of depression. The pharmacological blockade or genetic deletion of the NK1 receptor, or the substance P coding gene tac1 led to a decreased emotionality and a reduction of depression-related behaviours in different animal models. In order to characterize molecular changes associated with reduced SP-NK1 signalling in animal models of depression, we assessed the regulation of the CRH system. First, tac1 −/− animals and tac1 +/+ controls were subjected to bulbectomy, which induces physiological and behavioural changes that are relevant to depression. We demonstrate that tac1 −/− animals, in contrast to tac1 +/+ controls, do not show anhedonia in the saccharine preference test after bulbectomy. Next, we studied expression levels of CRH, the receptors CRHR1 and CRHR2, and the binding protein CRHBP in the cortex and paraventricular nucleus using real-time RT-PCR. Our results show a strong induction of CRH, CRHBP and CRHR1 expression in the cortex of tac1 −/−, but not in tac1 +/+ animals. In the PVN, bulbectomized tac1 −/− mice showed an elevated expression of CRHR1 and CRHR2. These results show that substance P/NKA is involved in modulating CRH signalling in an animal model of depression.

Palatable cafeteria diet ameliorates anxiety and depression-like symptoms following an adverse early environment

Early trauma contributes to psychosocial disorders later in life. An adverse early environment induced by maternal separation (MS) is known to alter behavioural and stress responses in rats. Palatable food dampens stress responses. We investigated the influence of palatable cafeteria high-fat diet (HFD) on behavioural responses following MS or non-handling (NH), versus 15min brief separation. After littering, Sprague-Dawley rats were exposed to short separation, S15 (15min), prolonged separation, S180 (180min) daily from postnatal days 2 to 14 or were non-handled. Pups were assigned to HFD or chow at weaning. We assessed depression and anxiety-like behaviour with sucrose preference test (SPT) and elevated plus maze (EPM) respectively, and measured hypothalamic CRH and hippocampal glucocorticoid receptor (GR) expression. S180 rats showed increased anxiety-and depression-like behaviours, with increased plasma corticosterone, hypothalamic CRH, and reduced hippocampal GR expression versus S15 rats. Similar effects were observed across gender. These were normalized by provision of HFD, with greater beneficial effects in males. S15 showed no benefit of HFD. NH female rats had less adverse impacts; HFD had beneficial impact on behaviour in NH males. Thus behavioural deficits and gene expression changes induced by early life stress were ameliorated by HFD. These results highlight the important place of palatable food in reducing central stress responses supporting the therapeutic value of 'comfort food'.

Transgenic Mice Expressing Green Fluorescent Protein under the Control of the Corticotropin-Releasing Hormone Promoter

CRH is widely expressed in the brain and is of broad functional relevance to a number of physiological processes, including stress response, parturition, immune response, and ingestive behavior. To delineate further the organization of the central CRH network, we generated mice expressing green fluorescent protein (GFP) under the control of the CRH promoter, using bacterial artificial chromosome technology. Here we validate CRH-GFP transgene expression within specific brain regions and confirm the distribution of central GFP-producing cells to faithfully recapitulate that of CRH-expressing cells. Furthermore, we confirm the functional integrity of a population of GFP-producing cells by demonstrating their opposite responsiveness to nutritional status. We anticipate that this transgenic model will lend itself as a highly tractable tool for the investigation of CRH expression and function in discrete brain regions.

Stress sensitivity is increased in transgenic rats with low brain angiotensinogen

AT(1) blockers attenuate hypothalamo-pituitary-adrenal (HPA) axis reactivity in hypertension independently of their potency to lower blood pressure. A reduced pituitary sensitivity to CRH and a downregulation of hypothalamic CRH expression have been suggested to influence HPA axis activity during chronic AT(1) blockade. This study was aimed at confirming the role of central angiotensin II in regulating HPA reactivity by using the transgenic rat TGR(ASrAOGEN), a model featuring low levels of brain angiotensinogen. Different stress tests were performed to determine HPA reactivity in TGR(ASrAOGEN) and appropriate controls. In TGR(ASrAOGEN), blood pressure was diminished compared to controls. The corticosterone response to a CRH or ACTH challenge and a forced swim test was more distinct in TGR(ASrAOGEN) than it was in controls and occurred independently of a concurrent enhancement in ACTH. Using quantitative real-time PCR, we found increased mRNA levels of melanocortin 2 (Mc2r) and AT(2) receptors (Agtr2) in the adrenals of TGR(ASrAOGEN), whereas mRNA levels of Crh, Pomc, and AT(1) receptors (Agtr1) remained unchanged in hypothalami and pituitary glands. Since stress responses were increased rather than attenuated in TGR(ASrAOGEN), we conclude that the reduced HPA reactivity during AT(1) blockade could not be mimicked in a specific transgenic rat model featuring a centrally inactivated renin-angiotensin-aldosterone system. The ACTH independency of the enhanced corticosterone release during CRH test and the enhanced corticosterone response to ACTH rather indicates an adrenal mechanism. The upregulation of adrenal MC2 and AT(2) receptors seems to be involved in the stimulated facilitation of adrenal corticosterone release for effectuating the stimulated stress responses.