Mechanisms of Imidacloprid-Induced Alteration of Hypothalamic-Pituitary-Adrenal (HPA Axis after Subchronic Exposure in Male Rats

Directory of Open Access Journals (Sweden)

Alya Annabi

2015-11-01

Full Text Available Imidacloprid (IMI is known to target the nicotinic acetylcholine receptors (nAChRs in insects, and potentially in mammals. However, IMI toxicity on mammalian tissues has not been adequately evaluated. The aim of the present study was to examine whether IMI induced functional impairment in hypthalamic-pituitary-adrenal (HPA axis tissues. An oral exposure of 40 mg IMI/kg for 28 days in male rats caused a significant increase in malondialdehyde (MDA level. The antioxidant catalase, superoxide dismutase, and glutathione S-transferase showed various alterations following administration, but a significantly depleted thiol (SH groups was only recorded in hypothalamic tissues. The increase in the relative weight of adrenal glands and the increased adrenal cholesterol and plasma adrenocorticotropic hormone (ACTH levels are indicative of general adaptation syndrome. The hypothalamic and pituitary acetylcholinesterase activity and calcium level were significantly increased, highlighting the alteration of cholinergic transmission. In conclusion, the findings obtained show that chronic exposure to IMI may alter biochemical processes of HPA axis.

Beyond the HPA-axis: The role of the gonadal steroid hormone receptors in modulating stress-related responses in an animal model of PTSD.

Science.gov (United States)

Fenchel, Daphna; Levkovitz, Yechiel; Vainer, Ella; Kaplan, Zeev; Zohar, Joseph; Cohen, Hagit

2015-06-01

The hypothalamic-pituitary-adrenal (HPA) axis, which plays a major role in the response to stress, and the hypothalamic-pituitary-gonadal (HPG) axis are closely linked with the ability to inhibit the other. Testosterone, a product of the HPG, has many beneficial effects beyond its functions as a sex hormone including anti-anxiety properties. In this study we examined the effect of stress exposure on gonadal hormones, and their efficacy in modulating anxiety-like response in an animal model of PTSD. Male rats were exposed to predator scent stress, followed by analysis of brain expression of androgen receptor (AR) receptor and estrogen receptor α (ERα). The behavioral effects of immediate treatment with testosterone, testosterone receptor antagonist (flutamide) or vehicle were evaluated using the elevated plus-maze, acoustic startle response and trauma-cue response. Levels of circulating corticosterone and testosterone were also measured after treatment. The behavioral effects of delayed testosterone treatment were explored in the same manner. We report that animals whose behavior was extremely disrupted (EBR) selectively displayed significant down-regulation of AR and ERα in the hippocampus. Immediate treatment with flutamide or delayed treatment with testosterone significantly increased prevalence rates of minimal behavioral response (MBR) and decreased prevalence of EBR with favorable behavioral results. Testosterone levels were higher in control un-exposed animals, while corticosterone was higher in control exposed animals. This study suggests that gonadal steroid hormones are involved in the neurobiological response to predator scent stress and thus warrant further study as a potential therapeutic avenue for the treatment of anxiety-related disorders. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

Hpa1 harpin needs nitroxyl terminus to promote vegetative growth and leaf photosynthesis in Arabidopsis.

Science.gov (United States)

Li, Xiaojie; Han, Liping; Zhao, Yanying; You, Zhenzhen; Dong, Hansong; Zhang, Chunling

2014-03-01

Hpa1 is a harpin protein produced by Xanthomonas oryzae, an important bacterial pathogen of rice, and has the growth-promoting activity in plants. To understand the molecular basis for the function of Hpa1, we generated an inactive variant protein, Hpa1 delta NT, by deleting the nitroxyl-terminal region of the Hpa1 sequence and compared Hpa1 delta NT with the full-length protein in terms of the effects on vegetative growth and related physiological responses in Arabidopsis. When Hpa1 was applied to plants, it acted to enhance the vegetative growth but did not affect the floral development. Enhanced plant growth was accompanied by induced expression of growth-promoting genes in plant leaves. The growth-promoting activity of Hpa1 was further correlated with a physiological consequence shown as promoted leaf photosynthesis as a result of facilitated CO2 conduction through leaf stomata and mesophyll cells. On the contrary, plant growth, growth-promoting gene expression, and the physiological consequence changed little in response to the Hpa1 delta NT treatment. These analyses suggest that Hpa1 requires the nitroxyl-terminus to facilitate CO2 transport inside leaf cells and promote leaf photosynthesis and vegetative growth of the plant.

Performance analysis of AF cooperative systems with HPA nonlinearity in semi-blind relays

KAUST Repository

Qi, Jian

2012-12-01

In this paper, dual-hop amplify-and-forward (AF) cooperative systems in the presence of high-power amplifier (HPA) nonlinearity at semi-blind relays, are investigated. Based on the modified AF cooperative system model taking into account the HPA nonlinearity, the expression for the output signal-to-noise ratio (SNR) at the destination node is derived, where the interference due to both the AF relaying mechanism and the HPA nonlinearity is characterized. The performance of the AF cooperative system under study is evaluated in terms of average symbol error probability (SEP), which is derived using the moment-generating function (MGF) approach, considering transmissions over Nakagami-m fading channels. Numerical results are provided and show the effects of some system parameters, such as the HPA parameters, numbers of relays, quadrature amplitude modulation (QAM) order, Nakagami parameters, on performance. © 2012 IEEE.

Performance analysis of AF cooperative systems with HPA nonlinearity in semi-blind relays

KAUST Repository

Qi, Jian; Aï ssa, Sonia; Alouini, Mohamed-Slim

2012-01-01

In this paper, dual-hop amplify-and-forward (AF) cooperative systems in the presence of high-power amplifier (HPA) nonlinearity at semi-blind relays, are investigated. Based on the modified AF cooperative system model taking into account the HPA nonlinearity, the expression for the output signal-to-noise ratio (SNR) at the destination node is derived, where the interference due to both the AF relaying mechanism and the HPA nonlinearity is characterized. The performance of the AF cooperative system under study is evaluated in terms of average symbol error probability (SEP), which is derived using the moment-generating function (MGF) approach, considering transmissions over Nakagami-m fading channels. Numerical results are provided and show the effects of some system parameters, such as the HPA parameters, numbers of relays, quadrature amplitude modulation (QAM) order, Nakagami parameters, on performance. © 2012 IEEE.

HPA e Nitro-HPA em Ambiente Semifechado Impactado por Emissão da Combustão de Diesel/Biodiesel (B5

Directory of Open Access Journals (Sweden)

Fabio Cal Sabino

2015-09-01

Full Text Available Com o objetivo de verificar a presença de HPA e nitro-HPA associados à fração fina do material particulado (MP1,0 e MP2,5 proveniente da combustão de mistura diesel/biodiesel (B5 foram realizadas amostragens diárias no terminal urbano de ônibus de Londrina. Para a determinação do nitro-HPA foi utilizada a espectroscopia de massa acoplado à cromatografia a líquido com ionização química a pressão atmosférica e detector por aprisionamento de íons. Os HPA foram determinados por cromatografia a líquido com detecções por fluorescência e arranjo de fotodiodos. Foram determinados 9 HPA e 1-nitropireno. As concentrações dos HPA de 4 a 6 anéis (FLUT, PIR, CRI, BBF, BKF e DBA foram mais elevadas em comparação aos HPA mais leves (ACE, FLU e ANT. A ∑HPA associado ao MP1,0 correspondeu a 66% do MP2,5 com concentrações que excedem ao recomendado pela OMS. As razões de diagnóstico para pares de HPA e NHPA foram calculadas e seus valores são indicativos das emissões B5. O uso de bicombustíveis no território brasileiro é estimulado e o acompanhamento das alterações nas emissões decorrentes dos processos de combustão é importante e necessário para inferir sobre a alteração da qualidade do ar e o impacto sobre o ambiente.

Cognition and HPA axis reactivity in mildly to moderately depressed outpatients

DEFF Research Database (Denmark)

Krogh, Jesper; Videbech, Poul; Renvillard, Signe Groth

2012-01-01

Background: Patients with depression display neurobiological changes of the hypothalamic-pituitary axis as well as cognitive disturbances. Aims: To assess any association between hypothalamus-pituitary-adrenal (HPA) axis reactivity and memory-related cognitive functions. Methods: Depressed...... the following day at the same times. Results: Patients and controls did not differ on any memory-related cognitive skills. After dexamethasone the cortisol level was 1.7 nmol/l higher (95% CI 0.0-2.8, P =¿0.05) in depressed patients compared with controls. In the control group, but not in the patients...... after dexamethasone and visuo-spatial memory primarily driven by the healthy controls. Otherwise, no association were found between HPA axis reactivity and memory-related cognitive function....

Maternal early-life trauma and affective parenting style: the mediating role of HPA-axis function.

Science.gov (United States)

Juul, Sarah H; Hendrix, Cassandra; Robinson, Brittany; Stowe, Zachary N; Newport, D Jeffrey; Brennan, Patricia A; Johnson, Katrina C

2016-02-01

A history of childhood trauma is associated with increased risk for psychopathology and interpersonal difficulties in adulthood and, for those who have children, impairments in parenting and increased risk of negative outcomes in offspring. Physiological and behavioral mechanisms are poorly understood. In the current study, maternal history of childhood trauma was hypothesized to predict differences in maternal affect and HPA axis functioning. Mother-infant dyads (N = 255) were assessed at 6 months postpartum. Mothers were videotaped during a 3-min naturalistic interaction, and their behavior was coded for positive, neutral, and negative affect. Maternal salivary cortisol was measured six times across the study visit, which also included an infant stressor paradigm. Results showed that childhood trauma history predicted increased neutral affect and decreased mean cortisol in the mothers and that cortisol mediated the association between trauma history and maternal affect. Maternal depression was not associated with affective measures or cortisol. Results suggest that early childhood trauma may disrupt the development of the HPA axis, which in turn impairs affective expression during mother-infant interactions in postpartum women. Interventions aimed at treating psychiatric illness in postpartum women may benefit from specific components to assess and treat trauma-related symptoms and prevent secondary effects on parenting.

Update on stress and depression: the role of the hypothalamic-pituitary-adrenal (HPA axis

Directory of Open Access Journals (Sweden)

Mello Andrea de Abreu Feijó de

2003-01-01

Full Text Available Over the past 50 years, relationships between stress and the neurobiological changes seen in psychiatric disorders have been well-documented. A major focus of investigations in this area has been the role of the hypothalamic-pituitary-adrenal (HPA axis, both as a marker of stress response and as a mediator of additional downstream pathophysiologic changes. This review examines the emerging literature concerning the relationship between stress, HPA axis function, and depression, as well as the role of early life stress as an important risk factor for HPA axis dysregulation. The more recent studies reviewed suggest that the prominence of HPA axis hyperactivity in adults with depressive and anxiety disorders may constitute a link between the occurrence of adversity in childhood and the development of adult psychopathology

Progressive dysregulation of autonomic and HPA axis functions in HIV-1 clade C infection in South India.

Science.gov (United States)

Chittiprol, Seetharamaiah; Kumar, Adarsh M; Satishchandra, P; Taranath Shetty, K; Bhimasena Rao, R S; Subbakrishna, D K; Philip, Mariyamma; Satish, K S; Ravi Kumar, H; Kumar, Mahendra

2008-01-01

Human immunodeficiency virus type 1 (HIV-1) infection causes a wide spectrum of abnormalities in neurological, neuropsychological, and neuroendocrinological functions. Several studies report disturbance in autonomic nervous system (ANS) and hypothalamic pituitary-adrenal (HPA) axis function in HIV-1B infected individuals. However, no such investigations on the effect of HIV-1 clade C infection, particularly during the initial phase of the disease progression, have been reported. The present investigations were carried out longitudinally over a 2-year period at 12 monthly intervals in clinically asymptomatic HIV-1 clade C seropositive patients (n=120) and seronegative control subjects (n=29). We determined both the basal levels and the dynamic changes in plasma levels of norepinephrine (NE), epinephrine (E), adrenocorticotrophic hormone (ACTH) and cortisol (CORT). Studies were also extended longitudinally (at three separate yearly visits of each participant), to evaluate the response of autonomic and HPA axis to mirror star tracing challenge test (MSTCT) and the values were determined as area under the curve (AUC, corrected for baseline levels of NE, E, ACTH, and CORT). The findings show that the values of basal plasma NE levels, as well as NE response to MSTCT (AUC) at the first visit of HIV-1 seropositive individuals did not differ from those found in the control subjects (NE, pg/ml, HIV-1C=313.5+/-12.7 vs. controls=353.0+/-21.3; p=NS; AUC, HIV-1C=225+/-14.75 vs. controls=232.7+/-19.34; p=NS, respectively). At the subsequent two visits of HIV-1 positive patients however, NE response to MSTCT challenge was progressively attenuated (AUC=235+/-19.5 and 162.7+/-13.6; p<0.01 and 0.05, respectively) compared to that found at the first visit. On the other hand, plasma levels of E as well as E response to MSTCT at the first visit were significantly lower in HIV-1C seropositive individuals compared to those in the control subjects (pg/ml, HIV-1C=77.30+/-5.7 vs. controls

Impaired glucocorticoid-mediated HPA axis negative feedback induced by juvenile social isolation in male rats.

Science.gov (United States)

Boero, Giorgia; Pisu, Maria Giuseppina; Biggio, Francesca; Muredda, Laura; Carta, Gianfranca; Banni, Sebastiano; Paci, Elena; Follesa, Paolo; Concas, Alessandra; Porcu, Patrizia; Serra, Mariangela

2018-05-01

We previously demonstrated that socially isolated rats at weaning showed a significant decrease in corticosterone and adrenocorticotropic hormone (ACTH) levels, associated with an enhanced response to acute stressful stimuli. Here we shown that social isolation decreased levels of total corticosterone and of its carrier corticosteroid-binding globulin, but did not influence the availability of the free active fraction of corticosterone, both under basal conditions and after acute stress exposure. Under basal conditions, social isolation increased the abundance of glucocorticoid receptors, while it decreased that of mineralocorticoid receptors. After acute stress exposure, socially isolated rats showed long-lasting corticosterone, ACTH and corticotrophin releasing hormone responses. Moreover, while in the hippocampus and hypothalamus of group-housed rats glucocorticoid receptors expression increased with time and reached a peak when corticosterone levels returned to basal values, in socially isolated rats expression of glucocorticoid receptors did not change. Finally, social isolation also affected the hypothalamic endocannabinoid system: compared to group-housed rats, basal levels of anandamide and cannabinoid receptor type 1 were increased, while basal levels of 2-arachidonoylglycerol were decreased in socially isolated rats and did not change after acute stress exposure. The present results show that social isolation in male rats alters basal HPA axis activity and impairs glucocorticoid-mediated negative feedback after acute stress. Given that social isolation is considered an animal model of several neuropsychiatric disorders, such as generalized anxiety disorder, depression, post-traumatic stress disorder and schizophrenia, these data could contribute to better understand the alterations in HPA axis activity observed in these disorders. Copyright © 2018 Elsevier Ltd. All rights reserved.

Broadband S-band class E HPA

NARCIS (Netherlands)

Wanum, M.; van Dijk, R.; de Hek, A.P.; van Vliet, Frank Edward

2009-01-01

A broadband class E High Power Amplifier (HPA) is presented. This HPA is designed to operate at S-band (2.75 to 3.75 GHz). A power added efficiency of 50% is obtained for the two stage amplifier with an output power of 35.5 dBm on a chip area of 5.25 times 2.8 mm2.

The role of BDNF and HPA axis in the neurobiology of burnout syndrome.

Science.gov (United States)

Onen Sertoz, Ozen; Tolga Binbay, Ibrahim; Koylu, Ersin; Noyan, Aysin; Yildirim, Emre; Elbi Mete, Hayriye

2008-08-01

Chronic stress is known to affect the HPA axis. The few clinical studies which have been conducted on HPA-axis function in burnout have produced inconsistent results. The etiological relationship between sBDNF and burnout has not yet been studied. The aim of the current study was to investigate the role of BDNF and HPA axis in the neurobiology of burnout. In the current study 37 clinically diagnosed burnout participants were compared with 35 healthy controls in terms of BDNF, HPA axis, burnout symptoms, depression, anxiety and psychosomatic complaints. Basal serum cortisol, sBDNF and cortisol level after 1 mg DST was sampled. We found no significant differences in terms of HPA-axis function (for basal serum cortisol, p=0.592; for cortisol level after 1 mg DST, p=0.921), but we did find lowered sBDNF levels in burnout group (88.66+/-18.15 pg/ml) as compared to healthy controls (102.18+/-20.92 pg/ml) and the difference was statistically significant (p=0.005). Logistic Regression Analysis revealed that emotional exhaustion (p=0.05), depersonalization (p=0.005) and depression (p=0.025) were significantly associated with burnout. sBDNF levels correlated negatively with emotional exhaustion (r=-,268, p=0.026), depersonalization (r=-,333, p=0.005) and correlated positively with competence (r=0.293, p=0.015) sub-scales of burnout inventory. However, there were no significant relationships between cortisol levels and sBDNF levels (r=0.80, p=0.51), depression, anxiety, psychosomatic complaints and burnout inventory. Our results suggest that low BDNF might contribute to the neurobiology of burnout syndrome and it seems to be associated with burnout symptoms including altered mood and cognitive functions.

Environmental stressors and epigenetic control of the hypothalamic-pituitary-adrenal-axis (HPA-axis)

OpenAIRE

Lee, Richard; Sawa, Akira

2014-01-01

In this review, we provide a brief summary of several key studies that broaden our understanding of stress and its epigenetic control of the hypothalamic-pituitary-adrenal axis (HPA)-axis function and behavior. Clinical and animal studies suggest a link among exposure to stress, dysregulation of the HPA-axis, and susceptibility to neuropsychiatric illnesses. Recent studies have supported the notion that exposure to glucocorticoids and stress in various forms, duration, and intensity during di...

Stressor-specific effects of sex on HPA axis hormones and activation of stress-related neurocircuitry.

Science.gov (United States)

Babb, Jessica A; Masini, Cher V; Day, Heidi E W; Campeau, Serge

2013-11-01

Experiencing stress can be physically and psychologically debilitating to an organism. Women have a higher prevalence of some stress-related mental illnesses, the reasons for which are unknown. These experiments explore differential HPA axis hormone release in male and female rats following acute stress. Female rats had a similar threshold of HPA axis hormone release following low intensity noise stress as male rats. Sex did not affect the acute release, or the return of HPA axis hormones to baseline following moderate intensity noise stress. Sensitive indices of auditory functioning obtained by modulation of the acoustic startle reflex by weak pre-pulses did not reveal any sexual dimorphism. Furthermore, male and female rats exhibited similar c-fos mRNA expression in the brain following noise stress, including several sex-influenced stress-related regions. The HPA axis response to noise stress was not affected by stage of estrous cycle, and ovariectomy significantly increased hormone release. Direct comparison of HPA axis hormone release to two different stressors in the same animals revealed that although female rats exhibit robustly higher HPA axis hormone release after restraint stress, the same effect was not observed following moderate and high intensity loud noise stress. Finally, the differential effect of sex on HPA axis responses to noise and restraint stress cannot readily be explained by differential social cues or general pain processing. These studies suggest the effect of sex on acute stress-induced HPA axis hormone activity is highly dependent on the type of stressor.

Basal functioning of the hypothalamic-pituitary-adrenal (HPA) axis and psychological distress in recreational ecstasy polydrug users.

Science.gov (United States)

Wetherell, Mark A; Montgomery, Catharine

2014-04-01

Ecstasy (MDMA) is a psychostimulant drug which is increasingly associated with psychobiological dysfunction. While some recent studies suggest acute changes in neuroendocrine function, less is known about long-term changes in HPA functionality in recreational users. The current study is the first to explore the effects of ecstasy-polydrug use on psychological distress and basal functioning of the HPA axis through assessing the secretion of cortisol across the diurnal period. Seventy-six participants (21 nonusers, 29 light ecstasy-polydrug users, 26 heavy ecstasy-polydrug users) completed a substance use inventory and measures of psychological distress at baseline, then two consecutive days of cortisol sampling (on awakening, 30 min post awakening, between 1400 and 1600 hours and pre bedtime). On day 2, participants also attended the laboratory to complete a 20-min multitasking stressor. Both user groups exhibited significantly greater levels of anxiety and depression than nonusers. On day 1, all participants exhibited a typical cortisol profile, though light users had significantly elevated levels pre-bed. On day 2, heavy users demonstrated elevated levels upon awakening and all ecstasy-polydrug users demonstrated elevated pre-bed levels compared to non-users. Significant between group differences were also observed in afternoon cortisol levels and in overall cortisol secretion across the day. The increases in anxiety and depression are in line with previous observations in recreational ecstasy-polydrug users. Dysregulated diurnal cortisol may be indicative of inappropriate anticipation of forthcoming demands and hypersecretion may lead to the increased psychological and physical morbidity associated with heavy recreational use of ecstasy.

Anti-HPA-1b Mediated Posttransfusion Purpura: A Case Report

Directory of Open Access Journals (Sweden)

O. P. Arewa

2013-01-01

Full Text Available Posttransfusion purpura (PTP is an uncommon, but potentially fatal, transfusion reaction characterized by profound thrombocytopenia and bleeding. PTP is caused by alloimmunization to human platelet specific antigens following blood component transfusion. Although there is evidence of a wide serological spectrum of culprit antibodies implicated, Anti-human-platelet-antigen- (HPA- 1a is the most common antibody in cases reported. We report a case of posttransfusion purpura in an African American. The patient was negative for HPA-1a antibodies, but anti-HPA-1b was identified with a platelet phenotype of HPA-1a/HPA-1a. Although less common, HPA-1b antibody may be an important consideration in posttransfusion purpura diagnosed in patients of African descent.

O eixo hipotálamo-pituitária-adrenal, a função dos receptores de glicocorticóides e sua importância na depressão The Hypothalamic Pituitary Adrenal axis, Glucocorticoid receptor function and relevance to depression

Directory of Open Access Journals (Sweden)

Mario F Juruena

2004-09-01

abordagem eficaz para maximizar os efeitos terapêuticos dos antidepressivos. Hipóteses referentes aos mecanismos destes receptores envolvem compostos não esteróides que regulam a função dos RGs via segundos mensageiros. A pesquisa nesta área trará novos entendimentos à fisiopatologia e ao tratamento dos transtornos afetivos, em especial na depressão.OBJECTIVES: Changes in the hypothalamic-pituitary-adrenocortical (HPA system are characteristic of depression. Because the effects of glucocorticoids are mediated by intracellular receptors including, most notably, the glucocorticoid receptor (GR, several studies have examined the number and/or function of GRs in depressed patients. METHODS: Review scientific evidences have consistently demonstrated that GR function is impaired in major depression, resulting in reduced GR-mediated negative feedback on the HPA axis and increased production and secretion of CRF in various brain regions postulated to be involved in the causality of depression. RESULTS: This article summarizes the literature on GR in depression and on the impact of antidepressants on the GR in clinical and preclinical studies, and supports the concept that impaired GR signalling is a key mechanism in the pathogenesis of depression, in the absence of clear evidence of decreased GR expression. The data also indicate that antidepressants have direct effects on the GR, leading to enhanced GR function and increased GR expression. Although the effects of antidepressants on glucocorticoid hormones and their receptors are relevant for the therapeutic action of these drugs, the molecular mechanisms underlying these effects are unclear. We propose that antidepressants in humans could inhibit steroid transporters localised on the blood-brain barrier and in neurones, like the multidrug resistance p-glycoprotein, and thus increase the access of cortisol to the brain and the glucocorticoid-mediated negative feedback on the HPA axis. CONCLUSION: Enhanced cortisol action

Saikosaponin D relieves unpredictable chronic mild stress induced depressive-like behavior in rats: involvement of HPA axis and hippocampal neurogenesis.

Science.gov (United States)

Li, Hong-Yan; Zhao, Ying-Hua; Zeng, Min-Jie; Fang, Fang; Li, Min; Qin, Ting-Ting; Ye, Lu-Yu; Li, Hong-Wei; Qu, Rong; Ma, Shi-Ping

2017-11-01

Saikosaponin D (SSD), a major bioactive component isolated from Radix Bupleuri, has been reported to exert neuroprotective properties. The present study was designed to investigate the anti-depressant-like effects and the potential mechanisms of SSD. Behavioural tests including sucrose preference test (SPT), open field test (OFT) and forced swim test (FST) were performed to study the antidepressant-like effects of SSD. In addition, we examined corticosterone and glucocorticoid receptor (GR) levels to evaluate hypothalamic-pituitary-adrenal (HPA) axis function. Furthermore, hippocampal neurogenesis was assessed by testing doublecortin (DCX) levels, and neurotrophic molecule levels were also investigated in the hippocampus of rats. We found that unpredictable chronic mild stress (UCMS) rats displayed lost body weight, decreased sucrose consumption in SPT, reduced locomotive activity in OFT, and increased immobility time in FST. Chronic treatment with SSD (0.75, 1.50 mg/kg) remarkably ameliorated the behavioral deficiency induced by UCMS procedure. SSD administration downregulated elevated serum corticosterone levels, as well as alleviated the suppression of GR expression and nuclear translocation caused by UCMS, suggesting that SSD is able to remit the dysfunction of HPA axis. In addition, Western blot and immunohistochemistry analysis showed that SSD treatment significantly increased the generation of neurons in the hippocampus of UCMS rats indicated by elevated DCX levels. Moreover, hippocampal neurotrophic molecule levels of UCMS rats such as phosphorylated cAMP response element binding protein (p-CREB) and brain-derived neurotrophic factor (BDNF) were raised after SSD treatment. Together, Our results suggest that SSD opposed UCMS-induced depressive behaviors in rats, which was mediated, partially, by the enhancement of HPA axis function and consolidation of hippocampal neurogenesis.

Modulation of HPA axis response to social stress in schizophrenia by childhood trauma.

Science.gov (United States)

Lange, Claudia; Huber, Christian G; Fröhlich, Daniela; Borgwardt, Stefan; Lang, Undine E; Walter, Marc

2017-08-01

HPA axis functioning plays an important role in the etiology of schizophrenia spectrum disorders (SSD). However, only few studies have examined HPA axis responsivity to psychosocial stress in SSD, and results are heterogeneous. Furthermore, childhood trauma is known to influence psychopathology and treatment outcome in SSD, but studies on the influence of childhood trauma on stress related HPA axis activity are missing. The purpose of this study was to investigate cortisol response to a psychosocial stress challenge in SSD patients, and to examine its association with severity of childhood trauma. The present study included 25 subacutely ill patients with a current episode of a chronic SSD and 25 healthy controls. Participants underwent the modified Trier Social Stress Test, and salivary cortisol levels were assessed. The childhood trauma questionnaire was used to assess severity of adverse life events. Overall, cortisol response was blunted in the patient group compared to the control group (pchildhood trauma experience: responders had experienced more emotional abuse in their past (pchildhood trauma might influence stress-related HPA axis activity in SSD. Our data contribute to the hypothesis that severity of childhood trauma may be of pathophysiological relevance in schizophrenia. In addition, it may be an overlooked factor contributing to inconsistent findings regarding HPA axis response to psychosocial stress in SSD. Copyright © 2017. Published by Elsevier Ltd.

Early life stress, HPA axis adaptation and mechanisms contributing to later health outcomes

Directory of Open Access Journals (Sweden)

Jayanthi eManiam

2014-05-01

Full Text Available Stress activates the hypothalamic-pituitary-adrenal (HPA axis, which then modulates the degree of adaptation and response to a later stressor. It is known that early life stress can impact on later health but less is known about how early life stress impairs HPA axis activity, contributing to maladaptation of the stress response system. Early life stress exposure (either prenatally or in the early postnatal period can impact developmental pathways resulting in lasting structural and regulatory changes that predispose to adulthood disease. Epidemiological, clinical and experimental studies have demonstrated that early life stress produces long-term hyper responsiveness to stress with exaggerated circulating glucocorticoids, and enhanced anxiety and depression-like behaviours. Recently, evidence has emerged on early life stress induced metabolic derangements, for example hyperinsulinemia and altered insulin sensitivity on exposure to a high energy diet later in life. This draws our attention to the contribution of later environment to disease vulnerability. Early life stress can alter the expression of genes in peripheral tissues, such as the glucocorticoid receptor and 11-beta hydroxysteroid dehydrogenase (11β-HSD1. We propose that interactions between altered HPA axis activity and liver 11β-HSD1 modulates both tissue and circulating glucocorticoid availability, with adverse metabolic consequences. This review discusses the potential mechanisms underlying early life stress induced maladaptation of the HPA axis, and its subsequent effects on energy utilisation and expenditure. The effects of positive later environments as a means of ameliorating early life stress induced health deficits, and proposed mechanisms underpinning the interaction between early life stress and subsequent detrimental environmental exposures on metabolic risk will be outlined. Limitations in current methodology linking early life stress and later health outcomes will also

Early-Life Stress, HPA Axis Adaptation, and Mechanisms Contributing to Later Health Outcomes

Science.gov (United States)

Maniam, Jayanthi; Antoniadis, Christopher; Morris, Margaret J.

2014-01-01

Stress activates the hypothalamic–pituitary–adrenal (HPA) axis, which then modulates the degree of adaptation and response to a later stressor. It is known that early-life stress can impact on later health but less is known about how early-life stress impairs HPA axis activity, contributing to maladaptation of the stress–response system. Early-life stress exposure (either prenatally or in the early postnatal period) can impact developmental pathways resulting in lasting structural and regulatory changes that predispose to adulthood disease. Epidemiological, clinical, and experimental studies have demonstrated that early-life stress produces long term hyper-responsiveness to stress with exaggerated circulating glucocorticoids, and enhanced anxiety and depression-like behaviors. Recently, evidence has emerged on early-life stress-induced metabolic derangements, for example hyperinsulinemia and altered insulin sensitivity on exposure to a high energy diet later in life. This draws our attention to the contribution of later environment to disease vulnerability. Early-life stress can alter the expression of genes in peripheral tissues, such as the glucocorticoid receptor and 11-beta hydroxysteroid dehydrogenase (11β-HSD1). We propose that interactions between altered HPA axis activity and liver 11β-HSD1 modulates both tissue and circulating glucocorticoid availability, with adverse metabolic consequences. This review discusses the potential mechanisms underlying early-life stress-induced maladaptation of the HPA axis, and its subsequent effects on energy utilization and expenditure. The effects of positive later environments as a means of ameliorating early-life stress-induced health deficits, and proposed mechanisms underpinning the interaction between early-life stress and subsequent detrimental environmental exposures on metabolic risk will be outlined. Limitations in current methodology linking early-life stress and later health outcomes will also be

Effects of Early-Life Adversity on Hippocampal Structures and Associated HPA Axis Functions.

Science.gov (United States)

Dahmen, Brigitte; Puetz, Vanessa B; Scharke, Wolfgang; von Polier, Georg G; Herpertz-Dahlmann, Beate; Konrad, Kerstin

2018-01-01

Early-life adversity (ELA) is one of the major risk factors for serious mental and physical health risks later in life. ELA has been associated with dysfunctional neurodevelopment, especially in brain structures such as the hippocampus, and with dysfunction of the stress system, including the hypothalamic-pituitary-adrenal (HPA) axis. Children who have experienced ELA are also more likely to suffer from mental health disorders such as depression later in life. The exact interplay of aberrant neurodevelopment and HPA axis dysfunction as risks for psychopathology is not yet clear. We investigated volume differences in the bilateral hippocampus and in stress-sensitive hippocampal subfields, behavior problems, and diurnal cortisol activity in 24 children who had experienced documented ELA (including out-of-home placement) in a circumscribed duration of adversity only in their first 3 years of life in comparison to data on 25 control children raised by their biological parents. Hippocampal volumes and stress-sensitive hippocampal subfields (Cornu ammonis [CA]1, CA3, and the granule-cell layer of the dentate gyrus [GCL-DG]) were significantly smaller in children who had experienced ELA, taking psychiatric diagnoses and dimensional psychopathological symptoms into account. ELA moderated the relationship between left hippocampal volume and cortisol: in the control group, hippocampal volumes were not related to diurnal cortisol, while in ELA children, a positive linear relationship between left hippocampal volume and diurnal cortisol was present. Our findings show that ELA is associated with altered development of the hippocampus, and an altered relationship between hippocampal volume and HPA axis activity in youth in care, even after they have lived in stable and caring foster family environments for years. Altered hippocampal development after ELA could thus be associated with a risk phenotype for the development of psychiatric disorders later in life. © 2017 S. Karger

Transgenic expression of a functional fragment of harpin protein Hpa1 in wheat induces the phloem-based defence against English grain aphid

Science.gov (United States)

Fu, Maoqiang; Xu, Manyu; Zhang, Chunling

2014-01-01

The harpin protein Hpa1 has multiple beneficial effects in plants, promoting plant growth and development, increasing crop yield, and inducing resistance to pathogens and insect pests. For these effects, the 10–40 residue fragment (Hpa110–42) isolated from the Hpa1 sequence is 1.3- to 7.5-fold more effective than the full-length protein. Here it is reported that the expression of Hpa110–42 under the direction of an insect-induced promoter induces the phloem-based defence to English grain aphid, a dominant species of wheat aphids. The expression of Hpa110–42 was found to compromise the colonization preference of aphids on the plant and further inhibit aphid reproduction in leaf colonies. In Hpa110–42-expressing wheat lines, moreover, aphid feeding from the phloem was repressed in correlation with the phloem-based defence. This defensive mechanism was shown as enhanced expression of wheat genes encoding phloem lectin proteins (PP2-A1 and PP2-A2) and β-1,3-glucan synthase-like enzymes (GSL2, GSL10, and GSL12). Both PP2-A and β-1,3-glucan formed high molecular mass polymers to block phloem sieve plate pores and therefore impede aphid feeding from the phloem. However, the phloem-based defence was impaired by treating plants with ethylene signalling inhibitors, suggesting the requirement for the ethylene signalling pathway. In addition, if Hpa110–42-expressing plants were subjected to attack by a small number of aphids, they newly acquired agriculturally beneficial characters, such as enhanced vegetative growth and increased tiller numbers and grain output values. These results suggest that the defensive and developmental roles of Hpa110–42 can be integrated into the germplasm of this agriculturally significant crop. PMID:24676030

Dysregulation of the hypothalamic pituitary adrenal (HPA) axis and physical performance at older ages: An individual participant meta-analysis

NARCIS (Netherlands)

Gardner, M.P.; Lightman, S.; Sayer, A.A.; Cooper, C.; Cooper, R.; Deeg, D.J.H.; Ebrahim, S.; Gallacher, J.; Kivimaki, M.; Kumari, M.; Kuh, D; Martin, R.M.; Peeters, G.; Ben-Shlomoa, Y.

2013-01-01

The association between functioning of the hypothalamic pituitary adrenal (HPA) axis and physical performance at older ages remains poorly understood. We carried out meta-analyses to test the hypothesis that dysregulation of the HPA axis, as indexed by patterns of diurnal cortisol release, is

The signal peptide-like segment of hpaXm is required for its association to the cell wall in transgenic tobacco plants.

Science.gov (United States)

Li, Le; Miao, Weiguo; Liu, Wenbo; Zhang, Shujian

2017-01-01

Harpins, encoded by hrp (hypersensitive response and pathogenicity) genes of Gram-negative plant pathogens, are elicitors of hypersensitive response (HR). HpaXm is a novel harpin-like protein described from cotton leaf blight bacteria, Xanthomonas citri subsp. malvacearum-a synonym of X. campestris pv. malvacearum (Smith 1901-1978). A putative signal peptide (1-MNSLNTQIGANSSFL-15) of hpaXm was predicted in the nitroxyl-terminal (N-terminal)by SignalP (SignalP 3.0 server). Here, we explored the function of the N-terminal leader peptide like segment of hpaXm using transgenic tobacco (Nicotiana tabacum cv. Xanthi nc.). Transgenic tobacco lines expressing the full-length hpaXm and the signal peptide-like segment-deleted mutant hpaXmΔLP were developed using transformation mediated by Agrobacterium tumefaciens. The target genes were confirmed integrated into the tobacco genomes and expressed normally. Using immune colloidal-gold detection technique, hpaXm protein was found to be transferred to the cytoplasm, the cell membrane, and organelles such as chloroplasts, mitochondria, and nucleus, as well as the cell wall. However, the deletion mutant hpaXmΔLP expressed in transgenic tobacco was found unable to cross the membrane to reach the cell wall. Additionally, soluble proteins extracted from plants transformed with hpaXm and hpaXmΔLP were bio-active. Defensive micro-HR induced by the transgene expression of hpaXm and hpaXmΔLP were observed on transgenic tobacco leaves. Disease resistance bioassays to tobacco mosaic virus (TMV) showed that tobacco plants transformed with hpaXm and with hpaXmΔLP exhibited enhanced resistance to TMV. In summary, the N-terminal signal peptide-like segment (1-45 bp) in hpaXm sequence is not necessary for transgene expression, bioactivity of hpaXm and resistance to TMV in transgenic tobacco, but is required for the protein to be translocated to the cell wall.

Expressions of Hippocampal Mineralocorticoid Receptor (MR) and Glucocorticoid Receptor (GR) in the Single-Prolonged Stress-Rats

International Nuclear Information System (INIS)

Zhe, Du; Fang, Han; Yuxiu, Shi

2008-01-01

Post-traumatic stress disorder (PTSD) is a stress-related mental disorder caused by traumatic experience. Single-prolonged stress (SPS) is one of the animal models proposed for PTSD. Rats exposed to SPS showed enhanced inhibition of the hypothalamo-pituitary-adrenal (HPA) axis, which has been reliably reproduced in patients with PTSD. Mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) in the hippocampus regulate HPA axis by glucocorticoid negative feedback. Abnormalities in negative feedback are found in PTSD, suggesting that GR and MR might be involved in the pathophysiology of these disorders. In the present study, we performed immunohistochemistry and western blotting to examine the changes in hippocampal MR- and GR-expression after SPS. Immunohistochemistry revealed decreased MR- and GR-immunoreactivity (ir) in the CA1 of hippocampus in SPS animals. Change in GR sub-distribution was also observed, where GR-ir was shifted from nucleus to cytoplasm in SPS rats. Western blotting showed that SPS induced significantly decreased MR- and GR-protein in the whole hippocampus, although the degree of decreased expression of both receptors was different. Meanwhile, we also found the MR/GR ratio decreased in SPS rats. In general, SPS induced down-regulation of MR- and GR-expression. These findings suggest that MR and GR play critical roles in affecting hippocampal function. Changes in MR/GR ratio may be relevant for behavioral syndrome in PTSD

Transgenic expression of a functional fragment of harpin protein Hpa1 in wheat induces the phloem-based defence against English grain aphid.

Science.gov (United States)

Fu, Maoqiang; Xu, Manyu; Zhou, Ting; Wang, Defu; Tian, Shan; Han, Liping; Dong, Hansong; Zhang, Chunling

2014-04-01

The harpin protein Hpa1 has multiple beneficial effects in plants, promoting plant growth and development, increasing crop yield, and inducing resistance to pathogens and insect pests. For these effects, the 10-40 residue fragment (Hpa1₁₀₋₄₂) isolated from the Hpa1 sequence is 1.3- to 7.5-fold more effective than the full-length protein. Here it is reported that the expression of Hpa1₁₀₋₄₂ under the direction of an insect-induced promoter induces the phloem-based defence to English grain aphid, a dominant species of wheat aphids. The expression of Hpa1₁₀₋₄₂ was found to compromise the colonization preference of aphids on the plant and further inhibit aphid reproduction in leaf colonies. In Hpa1₁₀₋₄₂-expressing wheat lines, moreover, aphid feeding from the phloem was repressed in correlation with the phloem-based defence. This defensive mechanism was shown as enhanced expression of wheat genes encoding phloem lectin proteins (PP2-A1 and PP2-A2) and β-1,3-glucan synthase-like enzymes (GSL2, GSL10, and GSL12). Both PP2-A and β-1,3-glucan formed high molecular mass polymers to block phloem sieve plate pores and therefore impede aphid feeding from the phloem. However, the phloem-based defence was impaired by treating plants with ethylene signalling inhibitors, suggesting the requirement for the ethylene signalling pathway. In addition, if Hpa1₁₀₋₄₂-expressing plants were subjected to attack by a small number of aphids, they newly acquired agriculturally beneficial characters, such as enhanced vegetative growth and increased tiller numbers and grain output values. These results suggest that the defensive and developmental roles of Hpa1₁₀₋₄₂ can be integrated into the germplasm of this agriculturally significant crop.

Neuroactive steroids modulate HPA axis activity and cerebral brain-derived neurotrophic factor (BDNF) protein levels in adult male rats.

Science.gov (United States)

Naert, Gaëlle; Maurice, Tangui; Tapia-Arancibia, Lucia; Givalois, Laurent

2007-01-01

Depression is characterized by hypothalamo-pituitary-adrenocortical (HPA) axis hyperactivity. In this major mood disorder, neurosteroids and neurotrophins, particularly brain-derived neurotrophic factor (BDNF), seem to be implicated and have some antidepressant effects. BDNF is highly involved in regulation of the HPA axis, whereas neurosteroids effects have never been clearly established. In this systematic in vivo study, we showed that the principal neuroactive steroids, namely dehydroepiandrosterone (DHEA), pregnenolone (PREG) and their sulfate esters (DHEA-S and PREG-S), along with allopregnanolone (ALLO), stimulated HPA axis activity, while also modulating central BDNF contents. In detail, DHEA, DHEA-S, PREG, PREG-S and ALLO induced corticotropin-releasing hormone (CRH) and/or arginine vasopressin (AVP) synthesis and release at the hypothalamic level, thus enhancing plasma adrenocorticotropin hormone (ACTH) and corticosterone (CORT) concentrations. This stimulation of the HPA axis occurred concomitantly with BDNF modifications at the hippocampus, amygdala and hypothalamus levels. We showed that these neurosteroids induced rapid effects, probably via neurotransmitter receptors and delayed effects perhaps after metabolization in other neuroactive steroids. We highlighted that they had peripheral effects directly at the adrenal level by inducing CORT release, certainly after estrogenic metabolization. In addition, we showed that, at the dose used, only DHEA, DHEA-S and PREG-S had antidepressant effects. In conclusion, these results highly suggest that part of the HPA axis and antidepressant effects of neuroactive steroids could be mediated by BDNF, particularly at the amygdala level. They also suggest that neurosteroids effects on central BDNF could partially explain the trophic properties of these molecules.

HPA antibodies in Algerian multitransfused patients: Prevalence and involvement in platelet refractoriness.

Science.gov (United States)

Brouk, Hacene; Bertrand, Gérald; Zitouni, Selma; Djenouni, Amel; Martageix, Corinne; Griffi, Fatiha; Kaplan, Cecile; Ouelaa, Hanifa

2015-06-01

Patients receiving cellular blood components may form HLA or HPA antibodies. The frequency and the specificity of HPA antibodies after a series of blood transfusions have never been reported in the Algerian population which is ethnically diverse and runs a higher risk of platelet alloimmunization due to high b allelic frequencies observed for the HPA systems. 117 polytransfused patients were included in this study; the detection of HPA antibodies was performed by the Monoclonal Antibody-specific Immobilization of Platelet Antigens method (MAIPA). Post-transfusion platelet effectiveness was evaluated by the calculation of corrected count increment (CCI). The antibodies against platelets were detected in 10.26% of the patients. In this study, the platelet systems concerned by the alloimmunizations were specifically HPA-1, -3 and -5 with particular predominance of HPA-1. Twenty two patients were refractory to platelet transfusion, as assessed by a CCI; in which 64% have factors associated with increased platelet consumption. Platelet Immunization was found in 14% of platelet refractoriness (PTR) cases. 03 Anti-platelet antibodies were directed against GPIb-IX (n = 1), anti-HPA-1b (n = 1) and anti HPA-5b (n = 1) associated with anti-HLA antibodies in two cases. HLA and HPA alloimmunization is common among chronically transfused patients. PTR detection, identification of the underlying causes, and selection of the appropriate product for transfusion are fundamental to reduce the risk of major bleedings. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimal beamforming in MIMO systems with HPA nonlinearity

KAUST Repository

Qi, Jian

2010-09-01

In this paper, multiple-input multiple-output (MIMO) transmit beamforming (TB) systems under the consideration of nonlinear high-power amplifiers (HPAs) are investigated. The optimal beamforming scheme, with the optimal beamforming weight vector and combining vector, is proposed for MIMO systems with HPA nonlinearity. The performance of the proposed MIMO beamforming scheme in the presence of HPA nonlinearity is evaluated in terms of average symbol error probability (SEP), outage probability and system capacity, considering transmission over uncorrelated quasi-static frequency-flat Rayleigh fading channels. Numerical results are provided and show the effects of several system parameters, namely, parameters of nonlinear HPA, numbers of transmit and receive antennas, and modulation order of phase-shift keying (PSK), on performance. ©2010 IEEE.

Optimal beamforming in MIMO systems with HPA nonlinearity

KAUST Repository

Qi, Jian; Aissa, Sonia

2010-01-01

In this paper, multiple-input multiple-output (MIMO) transmit beamforming (TB) systems under the consideration of nonlinear high-power amplifiers (HPAs) are investigated. The optimal beamforming scheme, with the optimal beamforming weight vector and combining vector, is proposed for MIMO systems with HPA nonlinearity. The performance of the proposed MIMO beamforming scheme in the presence of HPA nonlinearity is evaluated in terms of average symbol error probability (SEP), outage probability and system capacity, considering transmission over uncorrelated quasi-static frequency-flat Rayleigh fading channels. Numerical results are provided and show the effects of several system parameters, namely, parameters of nonlinear HPA, numbers of transmit and receive antennas, and modulation order of phase-shift keying (PSK), on performance. ©2010 IEEE.

Change in parent-child conflict and the HPA-axis: Where should we be looking and for how long?

Science.gov (United States)

Kuhlman, Kate R.; Repetti, Rena L.; Reynolds, Bridget M.; Robles, Theodore F.

2017-01-01

Objective Salivary cortisol is increasingly used as a longitudinal indicator of change in neuroendocrine regulation and as a predictor of health outcomes in youth. The purpose of this study was to describe which indices of HPA-axis functioning are sensitive to changes in parent-child conflict over a three week period and to explore the time course under which these changes can be measured. Methods Youth (n = 47; ages 8–13) completed daily diaries of their conflict with parents for 56 days. On days 17–18 and 38–39, youth contributed saliva samples upon waking, 30-minutes post-waking, afternoon, and bedtime. We assessed change in average diurnal HPA-axis functioning between day 17–18 and day 38–39 as a function of the slopes of change in parent-child conflict over 3 weeks. Results Increasing parent-child conflict was positively associated with concurrent increases in total cortisol output (AUCg), flattening of the diurnal slope, and increases in cortisol at bedtime, but not with change in the cortisol awakening response (CAR). Further, associations between parent-child conflict and both AUCg and bedtime cortisol were observed with at least 14 days of daily diary reporting, whereas any additional ratings of conflict beyond 3 days of daily diaries did not improve model fit for changes in diurnal slope. Conclusions This study demonstrates the within-subject up-regulation of the HPA-axis across three weeks in a healthy sample of youth exposed to natural increases in family conflict. In particular, cortisol at bedtime may be the HPA-axis index that is most sensitive to change over time in parent-child conflict, above and beyond conflict occurring that day. Further, when testing associations between family stressors and diurnal cortisol, the optimal schedule for assessing parent-child conflict varies for different indices of HPA-axis functioning. PMID:26963373

The effects of stress on hypothalamic-pituitary-adrenal (HPA) axis function in subjects with schizophrenia

NARCIS (Netherlands)

P.C. Guest (Paul); D. Martins-de-Souza (Daniel); H. Rahmoune (Hassan); S. Bahn (Sabine); P.C. Guest (Paul)

2013-01-01

textabstractOver the last few decades, evidence has been emerging that the pathogenesis of psychiatric disorders such as schizophrenia can involve perturbations of the hypothalamic-pituitary-adrenal (HPA) axis. Variations in the manifestation of these effects could be related to the differences in

The HPA photon protocol and proposed electron protocol

International Nuclear Information System (INIS)

Pitchford, W.G.

1985-01-01

The Hospital Physicists Association (HPA) photon dosimetry protocol has been produced and was published in 1983. Revised values of some components of Csub(lambda) and refinements introduced into the theory in the last few years have enabled new Csub(lambda) values to be produced. The proposed HPA electron protocol is at present in draft form and will be published shortly. Both protocels are discussed. (Auth.)

Interlaboratory variation in the detection of HPA-specific alloantibodies and in molecular HPA typing

NARCIS (Netherlands)

Allen, D.; Ouwehand, W. H.; de Haas, M.; Kekomaki, R.; Kaplan, C.; Metcalfe, P.

2007-01-01

Platelet immunology quality assurance exercises have been organized by National Institute for Biological Standards and Control since 1991 and, as of 2006, 35 laboratories participate in the serology section. Molecular human platelet antigen (HPA) typing has been included in the exercises since 1998

Increased cortisol responsivity to adrenocorticotropic hormone and low plasma levels of interleukin-1 receptor antagonist in women with functional hypothalamic amenorrhea.

Science.gov (United States)

Lindahl, Magnus S; Olovsson, Matts; Nyberg, Sigrid; Thorsen, Kim; Olsson, Tommy; Sundström Poromaa, Inger

2007-01-01

To assess the hypothalamic-pituitary-adrenal (HPA) axis at all levels, to determine the origin of the previously reported hypercortisolism in patients with functional hypothalamic amenorrhea. A secondary aim was to evaluate factors outside the central nervous system which are known to affect the HPA axis, i.e., circulating levels of interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1Ra), and fat mass-adjusted leptin levels, in patients with functional hypothalamic amenorrhea and healthy controls. Cross-sectional study. Umeå University Hospital, Umeå, Sweden. Fifteen subjects with hypothalamic amenorrhea, and 14 age- and weight-matched controls. None. We collected blood samples four times during a 24-hour interval for analysis of cortisol, leptin, IL-1Ra, and IL-6 levels. We performed a low-dose oral dexamethasone test and a low-dose ACTH test. We measured body-fat percentage using a dual-energy X-ray absorptiometer. Patients with hypothalamic amenorrhea had increased diurnal cortisol levels (P<.001). The cortisol response to intravenous low-dose ACTH was increased in functional hypothalamic amenorrhea patients compared to control subjects (P<.01), but they had similar rates of dexamethasone suppression. Patients with hypothalamic amenorrhea also had decreased diurnal leptin (P<.05), and decreased diurnal IL-1Ra levels (P<.05), compared to controls. Body-fat percentage was the main predictor of leptin levels. The present study suggests novel links for the development of functional hypothalamic amenorrhea, including increased adrenal responsiveness and impairments in proinflammatory cytokine pathways.

Interaction of lectins with membrane receptors on erythrocyte surfaces.

Science.gov (United States)

Sung, L A; Kabat, E A; Chien, S

1985-08-01

The interactions of human genotype AO erythrocytes (red blood cells) (RBCs) with N-acetylgalactosamine-reactive lectins isolated from Helix pomatia (HPA) and from Dolichos biflorus (DBA) were studied. Binding curves obtained with the use of tritium-labeled lectins showed that the maximal numbers of lectin molecules capable of binding to human genotype AO RBCs were 3.8 X 10(5) and 2.7 X 10(5) molecules/RBC for HPA and DBA, respectively. The binding of one type of lectin may influence the binding of another type. HPA was found to inhibit the binding of DBA, but not vice versa. The binding of HPA was weakly inhibited by a beta-D-galactose-reactive lectin isolated from Ricinus communis (designated RCA1). Limulus polyphemus lectin (LPA), with specificity for N-acetylneuraminic acid, did not influence the binding of HPA but enhanced the binding of DBA. About 80% of LPA receptors (N-acetylneuraminic acid) were removed from RBC surfaces by neuraminidase treatment. Neuraminidase treatment of RBCs resulted in increases of binding of both HPA and DBA, but through different mechanisms. An equal number (7.6 X 10(5) of new HPA sites were generated on genotypes AO and OO RBCs by neuraminidase treatment, and these new sites accounted for the enhancement (AO cells) and appearance (OO cells) of hemagglutinability by HPA. Neuraminidase treatment did not generate new DBA sites, but increased the DBA affinity for the existing receptors; as a result, genotype AO cells increased their hemagglutinability by DBA, while OO cells remained unagglutinable. The use of RBCs of different genotypes in binding assays with 3H-labeled lectins of known specificities provides an experimental system for studying cell-cell recognition and association.

Long-term effects of early parental loss due to divorce on the HPA axis.

Science.gov (United States)

Bloch, Miki; Peleg, Ido; Koren, Danny; Aner, Hamotal; Klein, Ehud

2007-04-01

We investigated the long-term effects of divorce and early separation from one parent on HPA axis reactivity, in young adults without psychopathology. Participants were 44 young subjects, 22 whose parents divorced before they reached age 10, and 22 controls. Psychiatric symptomatology was measured with the Brief Symptom Inventory (BSI), family perceived stress by the Dyadic Adjustment Scale (DAS), and bonding by the Parental Bonding Instrument (PBI). Assessment of HPA axis function included baseline morning cortisol and ACTH and cortisol response to a CRH stimulation test. No baseline or stimulated group differences were observed for ACTH. Cortisol levels were consistently but insignificantly lower in the divorce group throughout the CRH stimulation reaching statistical significance only at 5 min (p<0.03). Group by time effect reached a trend level (p<0.06). A correlation was found between psychiatric symptomatology and PBI scores; however, both parameters did not correlate with HPA axis activity. A significant correlation was found between DAS scores and ACTH. A regression model revealed a contributing effect for both family stress and child-parent bonding to stimulated ACTH levels. These preliminary findings suggest that even in the absence of adult psychopathology, a history of childhood separation from one parent due to divorce may lead to detectable, albeit mild, long-term alterations in HPA axis activity. Furthermore, they suggest that level of stress at home and parental bonding are important determinants of this effect. It is likely that divorce has significant and sustained effects on children's HPA axis only in the context of a traumatic separation.

Investigations of HPA Function and the Enduring Consequences of Stressors in Adolescence in Animal Models

Science.gov (United States)

McCormick, Cheryl M.; Mathews, Iva Z.; Thomas, Catherine; Waters, Patti

2010-01-01

Developmental differences in hypothalamic-pituitary-adrenal (HPA) axis responsiveness to stressors and ongoing development of glucocorticoid-sensitive brain regions in adolescence suggest that similar to the neonatal period of ontogeny, adolescence may also be a sensitive period for programming effects of stressors on the central nervous system.…

Dopamine D1 and D2 dopamine receptors regulate immobilization stress-induced activation of the hypothalamus-pituitary-adrenal axis.

Science.gov (United States)

Belda, Xavier; Armario, Antonio

2009-10-01

Whereas the role of most biogenic amines in the control of the hypothalamus-pituitary-adrenal (HPA) response to stress has been extensively studied, the role of dopamine has not. We studied the effect of different dopamine receptor antagonists on HPA response to a severe stressor (immobilization, IMO) in adult male Sprague-Dawley rats. Haloperidol administration reduced adrenocorticotropin hormone and corticosterone responses to acute IMO, particularly during the post-IMO period. This effect cannot be explained by a role of dopamine to maintain a sustained activation of the HPA axis as haloperidol did not modify the response to prolonged (up to 6 h) IMO. Administration of more selective D1 and D2 receptor antagonists (SCH23390 and eticlopride, respectively) also resulted in lower and/or shorter lasting HPA response to IMO. Dopamine, acting through both D1 and D2 receptors, exerts a stimulatory role on the activation of the HPA axis in response to a severe stressor. The finding that dopamine is involved in the maintenance of post-stress activation of the HPA axis is potentially important because the actual pathological impact of HPA activation is likely to be related to the area under the curve of plasma glucocorticoid levels, which is critically dependent on how long after stress high levels of glucocorticoid are maintained.

Embryonic GABA(B receptor blockade alters cell migration, adult hypothalamic structure, and anxiety- and depression-like behaviors sex specifically in mice.

Directory of Open Access Journals (Sweden)

Matthew S Stratton

Full Text Available Neurons of the paraventricular nucleus of the hypothalamus (PVN regulate the hypothalamic- pituitary-adrenal (HPA axis and the autonomic nervous system. Females lacking functional GABA(B receptors because of a genetic disruption of the R1 subunit have altered cellular characteristics in and around the PVN at birth. The genetic disruption precluded appropriate assessments of physiology or behavior in adulthood. The current study was conducted to test the long term impact of a temporally restricting pharmacological blockade of the GABA(B receptor to a 7-day critical period (E11-E17 during embryonic development. Experiments tested the role of GABA(B receptor signaling in fetal development of the PVN and later adult capacities for adult stress related behaviors and physiology. In organotypic slices containing fetal PVN, there was a female specific, 52% increase in cell movement speeds with GABA(B receptor antagonist treatment that was consistent with a sex-dependent lateral displacement of cells in vivo following 7 days of fetal exposure to GABA(B receptor antagonist. Anxiety-like and depression-like behaviors, open-field activity, and HPA mediated responses to restraint stress were measured in adult offspring of mothers treated with GABA(B receptor antagonist. Embryonic exposure to GABA(B receptor antagonist resulted in reduced HPA axis activation following restraint stress and reduced depression-like behaviors. There was also increased anxiety-like behavior selectively in females and hyperactivity in males. A sex dependent response to disruptions of GABA(B receptor signaling was identified for PVN formation and key aspects of physiology and behavior. These changes correspond to sex specific prevalence in similar human disorders, namely anxiety disorders and hyperactivity.

Social information changes stress hormone receptor expression in the songbird brain.

Science.gov (United States)

Cornelius, Jamie M; Perreau, Gillian; Bishop, Valerie R; Krause, Jesse S; Smith, Rachael; Hahn, Thomas P; Meddle, Simone L

2018-01-01

Social information is used by many vertebrate taxa to inform decision-making, including resource-mediated movements, yet the mechanisms whereby social information is integrated physiologically to affect such decisions remain unknown. Social information is known to influence the physiological response to food reduction in captive songbirds. Red crossbills (Loxia curvirostra) that were food reduced for several days showed significant elevations in circulating corticosterone (a "stress" hormone often responsive to food limitation) only if their neighbors were similarly food restricted. Physiological responses to glucocorticoid hormones are enacted through two receptors that may be expressed differentially in target tissues. Therefore, we investigated the influence of social information on the expression of the mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) mRNA in captive red crossbill brains. Although the role of MR and GR in the response to social information may be highly complex, we specifically predicted social information from food-restricted individuals would reduce MR and GR expression in two brain regions known to regulate hypothalamic-pituitary-adrenal (HPA) activity - given that reduced receptor expression may lessen the efficacy of negative feedback and release inhibitory tone on the HPA. Our results support these predictions - offering one potential mechanism whereby social cues could increase or sustain HPA-activity during stress. The data further suggest different mechanisms by which metabolic stress versus social information influence HPA activity and behavioral outcomes. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Simultaneous genotyping of HPA-17w to -21w by PCR-SSP in Chinese Cantonese.

Science.gov (United States)

Zhou, Haojie; Ding, Haoqiang; Chen, Yangkai; Li, Xiaofan; Ye, Xin; Nie, Yongmei

2015-01-01

Studies have reported the polymorphism of human platelet antigen (HPA)-17w, -18w, -19w, -20w, and -21w. However, the distribution of these five antigens in Chinese Cantonese is still unknown. In this study, we designed new sequence-specific primers for HPA-19w to -21w and used published primers for HPA-17w and -18w to develop a polymerase chain reaction with the sequence-specific primers (PCR-SSP) method for simultaneously genotyping HPA-17w to -21w. A total of 820 unrelated Cantonese apheresis platelet donors in Guangzhou were involved in this study. Among the five HPAs, complete a/a homozygosity was observed for HPA-17w to -20w with an allele frequency of 1.0000. For HPA-21w, nine individuals (9/820, 1.10%) were found to be HPA-21a/bw heterozygous and the allele frequencies of HPA-21a and HPA-21bw were 0.9945 (1631/1640) and 0.0055 (9/1640), respectively. The reliability of the PCR-SSP method was determined by comparing with the genotyping results by DNA sequencing, and no inconsistencies were observed between the two methods. This study provides a reliable PCR-SSP method for simultaneously genotyping HPA-17w to -21w and could improve HPA-matched platelet transfusion in Chinese Cantonese.

Activation of the Hypothalamic-Pituitary-Adrenal (HPA) Axis Following Extended Exposure to Atrazine (ATR)###

Science.gov (United States)

While it is known that adrenal steroids impact reproduction and a variety of other physiological and behavioral functions, disruption of the HPA-axis is not typically considered in toxicological studies. Here we characterize changes in basal corticosterone (CORT) and progesterone...

Modulation of central glucocorticoid receptors in short- and long-term experimental hyperthyroidism.

Science.gov (United States)

Nikolopoulou, Elena; Mytilinaios, Dimitrios; Calogero, Aldo E; Kamilaris, Themis C; Troupis, Theodore; Chrousos, George P; Johnson, Elizabeth O

2015-08-01

Hyperthyroidism is associated with a significant increase in circulating glucocorticoid levels and hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. The aim of this study was to examine whether the HPA axis hyperactivity observed in hyperthyroidism may be explained by a disturbed feedback inhibition of endogenous glucocorticoids through two specific intracellular receptors in the brain: the high affinity mineralocorticoid receptor (MR) and the lower affinity glucocorticoid receptor (GR). Cytosolic receptor binding and gene expression was assessed in rats with short (7 days) and long standing (60 days) eu- and hyperthyroidism. Glucocorticoid receptor number and binding affinity (Kd) in the hippocampus were measured using [(3)H2]-dexamethasone radioreceptor assay. In situ hybridization was employed to examine the effects of hyperthyroidism on the GR and MR mRNA levels in the hippocampus and the pituitary. Both short- and long-term hyperthyroid rats showed pronounced reduction in the concentration of cytosolic GR in the hippocampus, without changes in binding affinity or changes in GR expression. In contrast, GR mRNA in the pituitary increased after 7 days and decreased after 60 days of thyroxin treatment. MR mRNA was moderately affected. Hyperthyroidism is associated with significant decreases in hippocampal GR levels supporting the hypothesis that hyperactivity of the HPA axis observed in experimentally induced hyperthyroidism may be attributed, at least in part, to decreased negative feedback at the level of the hippocampus. These findings further support the notion that a central locus is principally responsible for the hyperactivity of the HPA axis observed in hyperthyroidism.

Mediator-dependent Nuclear Receptor Functions

Science.gov (United States)

Chen, Wei; Roeder, Robert

2011-01-01

As gene-specific transcription factors, nuclear hormone receptors are broadly involved in many important biological processes. Their function on target genes requires the stepwise assembly of different coactivator complexes that facilitate chromatin remodeling and subsequent preinitiation complex (PIC) formation and function. Mediator has proved to be a crucial, and general, nuclear receptor-interacting coactivator, with demonstrated functions in transcription steps ranging from chromatin remodeling to subsequent PIC formation and function. Here we discuss (i) our current understanding of pathways that nuclear receptors and other interacting cofactors employ to recruit Mediator to target gene enhancers and promoters, including conditional requirements for the strong NR-Mediator interactions mediated by the NR AF2 domain and the MED1 LXXLLL motifs and (ii) mechanisms by which Mediator acts to transmit signals from enhancer-bound nuclear receptors to the general transcription machinery at core promoters to effect PIC formation and function. PMID:21854863

Harpin Hpa1 Interacts with Aquaporin PIP1;4 to Promote the Substrate Transport and Photosynthesis in Arabidopsis.

Science.gov (United States)

Li, Liang; Wang, Hao; Gago, Jorge; Cui, Haiying; Qian, Zhengjiang; Kodama, Naomi; Ji, Hongtao; Tian, Shan; Shen, Dan; Chen, Yanjuan; Sun, Fengli; Xia, Zhonglan; Ye, Qing; Sun, Wei; Flexas, Jaume; Dong, Hansong

2015-11-26

Harpin proteins produced by plant-pathogenic Gram-negative bacteria are the venerable player in regulating bacterial virulence and inducing plant growth and defenses. A major gap in these effects is plant sensing linked to cellular responses, and plant sensor for harpin Hpa1 from rice bacterial blight pathogen points to plasma membrane intrinsic protein (PIP). Here we show that Arabidopsis AtPIP1;4 is a plasma membrane sensor of Hpa1 and plays a dual role in plasma membrane permeability of CO2 and H2O. In particular, AtPIP1;4 mediates CO2 transport with a substantial contribute to photosynthesis and further increases this function upon interacting with Hpa1 at the plasma membrane. As a result, leaf photosynthesis rates are increased and the plant growth is enhanced in contrast to the normal process without Hpa1-AtPIP1;4 interaction. Our findings demonstrate the first case that plant sensing of a bacterial harpin protein is connected with photosynthetic physiology to regulate plant growth.

Hpa1 harpin needs nitroxyl terminus to promote vegetative growth ...

Indian Academy of Sciences (India)

2014-01-27

Jan 27, 2014 ... When Hpa1 was applied to plants, it acted to enhance the vegetative growth but did not affect the .... Plants were grown in pots containing potting soils in an environ- mentally .... adapted to dark for 20 minutes and then adjusted to PPFD 1500 ... X. oryzae pv. oryzae Hpa1 contains 140 amino acids and has.

Recovery of HPA Axis Function After Successful Gonadotropin-Induced Pregnancy and Delivery in a Woman With Panhypopituitarism: Case Report and Review.

Science.gov (United States)

Wang, Yi; Zhang, Qiongyue; Yang, Jianzhi; Zhao, Xiaolong; He, Min; Shou, Xuefei; Li, Shiqi; Li, Yiming; Wang, Yongfei; Ye, Hongying

2015-09-01

Hypopituitarism is defined as the partial or complete defect of anterior pituitary hormone secretion. Patients with hypopituitarism usually need life-long hormone replacement therapy. However, in this case, we report a patient with panhypopituitarism whose hypothalamus-pituitary-adrenal (HPA) axis function was completely recovered after pregnancy and delivery. In this case study, we reported the case management and conducted a review of literature to identify the possible mechanism of pituitary function recovery. The patient who suffered from secondary amenorrhea was found a nonfunctioning pituitary macroadenoma, and the hormone test showed serum cortisol, FT3, FT4, thyrotropic hormone, and prolactin were at normal range. After surgical removal of the tumor which invasion in the sellar region, the patient had panhypopituitarism confirmed by the routine hormone test. Though spontaneous pregnancy is impossible in female patients with panhypopituitarism, the patient was restored fertility by the help of artificial reproductive techniques. After the confirmation of the pregnancy, levothyroixine was increased to 75 μg daily and readjusted to 150 μg daily before delivery according to the monthly measurement thyroid function. Hydrocortisone 10 mg daily replaced cortisone acetate; the dose was increased according to the symptoms of morning sickness. A single stress dose of hydrocortisone (200 mg) was used before elective cesarean delivery and was tapered to the dose of 10 mg per day in 1 week. Levothyroixine was reduced to 75 μg daily after delivery. During follow-up, her hypothalamus-pituitary-adrenal (HPA) axis function was completely recovered. The peak serum cortisol level could increase to 19.08 μg/dL by insulin-induced hypoglycemia. However, growth hormone remained unresponsive to the insulin-tolerance test, and thyroid hormone still needed exogenous supplementation. Hormone replacement therapy needed closely followed by endocrinologist and multidisciplinary

[Analysis of genetic polymorphism in randomized donor's HPA 1-16 antigens and establishment of typed platelet donor data bank].

Science.gov (United States)

Sun, Guo-Dong; Duan, Xian-Min; Zhang, Yan-Ping; Yin, Zhi-Zhu; Niu, Xiao-Li; Li, Yan-Feng; Niu, Hai-Jiang; Zhao, You-Liang

2005-10-01

To study the genetic polymorphism of HPA 1-16 platelet antigen alleles among unrelated volunteer donors and establish a typed platelet donor panel in Handan, typing was perfomed by polymerase chain reaction using sequence-specific primers (SSP-PCR); 148 random unrelated blood donors in Handan were genotyped for each of the HPA 1-16 antigen. The gene frequencies were analyzed and the genetype frequencies were determined by direct counting, and these data were compared with HPA distribution among various population by the chi-square test. The results indicated that HPA-1a, 2a, 4a-14a, 16a genes were found among the 16 HPAs in every sample tested. Monomorphic HPA-4a, 7a-14a, 16a were found in the samples. For HPA-1, 2, 5 and 6, a/a homozygosity was predominant with frequencies of 0.9595, 0.8108, 0.9865, 0.9797, respectively, and none of HPA b/b was found in the samples. HPA-1b, 2b, 5b, 6b were rarely found among subjects. HPA-15 had the greatest heterozygosity with a gene frequency of 0.2230, 0.5270, 0.2500 for HPA15a/15a, HPA15a/15b, HPA15b/15b, respectively. HPA-3 showed the second greatest heterozygosity with a gene frequency of 0.3851, 0.5135, 0.1014 for HPA3a/3a, HPA3a/3b, HPA3b/3b, respectively. HPA genotype frequencies showed a good fit to Hardy-Weinberg equilibrium. HPA1-5 gene frequencies for Chinese people in Handan were consistent with those of Chinese people in Shijiazhuang (P > 0.05). Among the HPA1-13, -15, the frequencies of HPA-1, -2, -6 for Chinese people in Handan differed appreciably from those for Chinese people in Taiwan (P Taiwan. Among the HPA 1 - 8, a similarity was noted between Chinese people in Handan and Koreans (P > 0.05), except for HPA-3. Frequencies of HPA-1, -2, -5 significantly were differed from those in African Americans, as compared with HPA 1-5 (P < 0.05). Comparison of gene frequencies from HPA-1 and -5 showed significant differences between Chinese people in Handan and people in UK (P < 0.05). It is concluded that HPA-2, -3, -5

Recovery by N-acetylcysteine from subchronic exposure to Imidacloprid-induced hypothalamic-pituitary-adrenal (HPA) axis tissues injury in male rats.

Science.gov (United States)

Annabi, Alya; Dhouib, Ines Bini; Lamine, Aicha Jrad; El Golli, Nargès; Gharbi, Najoua; El Fazâa, Saloua; Lasram, Mohamed Montassar

2015-01-01

Imidacloprid is the most important example of the neonicotinoid insecticides known to target the nicotinic acetylcholine receptor in insects, and potentially in mammals. N-Acetyl-l-cysteine (NAC) has been shown to possess curative effects in experimental and clinical investigations. The present study was designed to evaluate the recovery effect of NAC against Imidacloprid-induced oxidative stress and cholinergic transmission alteration in hypothalamic-pituitary-adrenal (HPA) axis of male rats following subchronic exposure. About 40 mg/kg of Imidacloprid was administered daily by intragastric intubation and 28 days later, the rats were sacrificed and HPA axis tissues were removed for different analyses. Imidacloprid increased adrenal relative weight and cholesterol level indicating an adaptive stage of the general alarm reaction to stress. Moreover, Imidacloprid caused a significant increase in malondialdehyde level, the antioxidants catalase, superoxide dismutase and glutathione-S-transferase showed various alterations following administration and significant depleted thiols content was only recorded in hypothalamic tissue. Furthermore, the hypothalamic and pituitary acetylcholinesterase activity and calcium level were significantly increased highlighting the alteration of cholinergic activity. The present findings revealed that HPA axis is a sensitive target to Imidacloprid (IMI). Interestingly, the use of NAC for only 7 days post-exposure to IMI showed a partial therapeutic effect against Imidacloprid toxicity.

Activation of presynaptic oxytocin receptors enhances glutamate release in the ventral hippocampus of prenatally restraint stressed rats.

Science.gov (United States)

Mairesse, Jérôme; Gatta, Eleonora; Reynaert, Marie-Line; Marrocco, Jordan; Morley-Fletcher, Sara; Soichot, Marion; Deruyter, Lucie; Camp, Gilles Van; Bouwalerh, Hammou; Fagioli, Francesca; Pittaluga, Anna; Allorge, Delphine; Nicoletti, Ferdinando; Maccari, Stefania

2015-12-01

Oxytocin receptors are known to modulate synaptic transmission and network activity in the hippocampus, but their precise function has been only partially elucidated. Here, we have found that activation of presynaptic oxytocin receptor with the potent agonist, carbetocin, enhanced depolarization-evoked glutamate release in the ventral hippocampus with no effect on GABA release. This evidence paved the way for examining the effect of carbetocin treatment in "prenatally restraint stressed" (PRS) rats, i.e., the offspring of dams exposed to repeated episodes of restraint stress during pregnancy. Adult PRS rats exhibit an anxious/depressive-like phenotype associated with an abnormal glucocorticoid feedback regulation of the hypothalamus-pituitary-adrenal (HPA) axis, and, remarkably, with a reduced depolarization-evoked glutamate release in the ventral hippocampus. Chronic systemic treatment with carbetocin (1mg/kg, i.p., once a day for 2-3 weeks) in PRS rats corrected the defect in glutamate release, anxiety- and depressive-like behavior, and abnormalities in social behavior, in the HPA response to stress, and in the expression of stress-related genes in the hippocampus and amygdala. Of note, carbetocin treatment had no effect on these behavioral and neuroendocrine parameters in prenatally unstressed (control) rats, with the exception of a reduced expression of the oxytocin receptor gene in the amygdala. These findings disclose a novel function of oxytocin receptors in the hippocampus, and encourage the use of oxytocin receptor agonists in the treatment of stress-related psychiatric disorders in adult life. Copyright © 2015 Elsevier Ltd. All rights reserved.

Functional programming of the autonomic nervous system by early life immune exposure: implications for anxiety.

Directory of Open Access Journals (Sweden)

Luba Sominsky

Full Text Available Neonatal exposure of rodents to an immune challenge alters a variety of behavioural and physiological parameters in adulthood. In particular, neonatal lipopolysaccharide (LPS; 0.05 mg/kg, i.p. exposure produces robust increases in anxiety-like behaviour, accompanied by persistent changes in hypothalamic-pituitary-adrenal (HPA axis functioning. Altered autonomic nervous system (ANS activity is an important physiological contributor to the generation of anxiety. Here we examined the long term effects of neonatal LPS exposure on ANS function and the associated changes in neuroendocrine and behavioural indices. ANS function in Wistar rats, neonatally treated with LPS, was assessed via analysis of tyrosine hydroxylase (TH in the adrenal glands on postnatal days (PNDs 50 and 85, and via plethysmographic assessment of adult respiratory rate in response to mild stress (acoustic and light stimuli. Expression of genes implicated in regulation of autonomic and endocrine activity in the relevant brain areas was also examined. Neonatal LPS exposure produced an increase in TH phosphorylation and activity at both PNDs 50 and 85. In adulthood, LPS-treated rats responded with increased respiratory rates to the lower intensities of stimuli, indicative of increased autonomic arousal. These changes were associated with increases in anxiety-like behaviours and HPA axis activity, alongside altered expression of the GABA-A receptor α2 subunit, CRH receptor type 1, CRH binding protein, and glucocorticoid receptor mRNA levels in the prefrontal cortex, hippocampus and hypothalamus. The current findings suggest that in addition to the commonly reported alterations in HPA axis functioning, neonatal LPS challenge is associated with a persistent change in ANS activity, associated with, and potentially contributing to, the anxiety-like phenotype. The findings of this study reflect the importance of changes in the perinatal microbial environment on the ontogeny of

Functional programming of the autonomic nervous system by early life immune exposure: implications for anxiety.

Science.gov (United States)

Sominsky, Luba; Fuller, Erin A; Bondarenko, Evgeny; Ong, Lin Kooi; Averell, Lee; Nalivaiko, Eugene; Dunkley, Peter R; Dickson, Phillip W; Hodgson, Deborah M

2013-01-01

Neonatal exposure of rodents to an immune challenge alters a variety of behavioural and physiological parameters in adulthood. In particular, neonatal lipopolysaccharide (LPS; 0.05 mg/kg, i.p.) exposure produces robust increases in anxiety-like behaviour, accompanied by persistent changes in hypothalamic-pituitary-adrenal (HPA) axis functioning. Altered autonomic nervous system (ANS) activity is an important physiological contributor to the generation of anxiety. Here we examined the long term effects of neonatal LPS exposure on ANS function and the associated changes in neuroendocrine and behavioural indices. ANS function in Wistar rats, neonatally treated with LPS, was assessed via analysis of tyrosine hydroxylase (TH) in the adrenal glands on postnatal days (PNDs) 50 and 85, and via plethysmographic assessment of adult respiratory rate in response to mild stress (acoustic and light stimuli). Expression of genes implicated in regulation of autonomic and endocrine activity in the relevant brain areas was also examined. Neonatal LPS exposure produced an increase in TH phosphorylation and activity at both PNDs 50 and 85. In adulthood, LPS-treated rats responded with increased respiratory rates to the lower intensities of stimuli, indicative of increased autonomic arousal. These changes were associated with increases in anxiety-like behaviours and HPA axis activity, alongside altered expression of the GABA-A receptor α2 subunit, CRH receptor type 1, CRH binding protein, and glucocorticoid receptor mRNA levels in the prefrontal cortex, hippocampus and hypothalamus. The current findings suggest that in addition to the commonly reported alterations in HPA axis functioning, neonatal LPS challenge is associated with a persistent change in ANS activity, associated with, and potentially contributing to, the anxiety-like phenotype. The findings of this study reflect the importance of changes in the perinatal microbial environment on the ontogeny of physiological processes.

CRF1 receptor-deficiency increases cocaine reward.

Science.gov (United States)

Contarino, Angelo; Kitchener, Pierre; Vallée, Monique; Papaleo, Francesco; Piazza, Pier-Vincenzo

2017-05-01

Stimulant drugs produce reward but also activate stress-responsive systems. The corticotropin-releasing factor (CRF) and the related hypothalamus-pituitary-adrenal (HPA) axis stress-responsive systems are activated by stimulant drugs. However, their role in stimulant drug-induced reward remains poorly understood. Herein, we report that CRF 1 receptor-deficient (CRF 1 -/-), but not wild-type, mice show conditioned place preference (CPP) responses to a relatively low cocaine dose (5 mg/kg, i.p.). Conversely, wild-type, but not CRF 1 -/-, mice display CPP responses to a relatively high cocaine dose (20 mg/kg, i.p.), indicating that CRF 1 receptor-deficiency alters the rewarding effects of cocaine. Acute pharmacological antagonism of the CRF 1 receptor by antalarmin also eliminates cocaine reward. Nevertheless, CRF 1 -/- mice display higher stereotypy responses to cocaine than wild-type mice. Despite the very low plasma corticosterone concentration, CRF 1 -/- mice show higher nuclear glucocorticoid receptor (GR) levels in the brain region of the hippocampus than wild-type mice. Full rescue of wild-type-like corticosterone and GR circadian rhythm and level in CRF 1 -/- mice by exogenous corticosterone does not affect CRF 1 receptor-dependent cocaine reward but induces stereotypy responses to cocaine. These results indicate a critical role for the CRF 1 receptor in cocaine reward, independently of the closely related HPA axis activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kupffer cell complement receptor clearance function and host defense.

Science.gov (United States)

Loegering, D J

1986-01-01

Kupffer cells are well known to be important for normal host defense function. The development of methods to evaluate the in vivo function of specific receptors on Kupffer cells has made it possible to assess the role of these receptors in host defense. The rationale for studying complement receptors is based on the proposed important role of these receptors in host defense and on the observation that the hereditary deficiency of a complement receptor is associated with recurrent severe bacterial infections. The studies reviewed here demonstrate that forms of injury that are associated with depressed host defense including thermal injury, hemorrhagic shock, trauma, and surgery also cause a decrease in complement receptor clearance function. This decrease in Kupffer cell receptor clearance function was shown not to be the result of depressed hepatic blood flow or depletion of complement components. Complement receptor function was also depressed following the phagocytosis of particulates that are known to depress Kupffer cell host defense function. Endotoxemia and bacteremia also were associated with a depression of complement receptor function. Complement receptor function was experimentally depressed in uninjured animals by the phagocytosis of IgG-coated erythrocytes. There was a close association between the depression of complement receptor clearance function and increased susceptibility to the lethal effects of endotoxin and bacterial infection. These studies support the hypotheses that complement receptors on Kupffer cells are important for normal host defense and that depression of the function of these receptors impairs host defense.

A randomized trial on mineralocorticoid receptor blockade in men: effects on stress responses, selective attention, and memory.

Science.gov (United States)

Cornelisse, Sandra; Joëls, Marian; Smeets, Tom

2011-12-01

Corticosteroids, released in high amounts after stress, exert their effects via two different receptors in the brain: glucocorticoid receptors (GRs) and mineralocorticoid receptors (MRs). GRs have a role in normalizing stress-induced effects and promoting consolidation, while MRs are thought to be important in determining the threshold for activation of the hypothalamic-pituitary-adrenal (HPA) axis. We investigated the effects of MR blockade on HPA axis responses to stress and stress-induced changes in cognitive function. In a double-blind, placebo-controlled study, 64 healthy young men received 400 mg of the MR antagonist spironolactone or placebo. After 1.5 h, they were exposed to either a Trier Social Stress Test or a non-stressful control task. Responses to stress were evaluated by hormonal, subjective, and physiological measurements. Afterwards, selective attention, working memory, and long-term memory performance were assessed. Spironolactone increased basal salivary cortisol levels as well as cortisol levels in response to stress. Furthermore, spironolactone significantly impaired selective attention, but only in the control group. The stress group receiving spironolactone showed impaired working memory performance. By contrast, long-term memory was enhanced in this group. These data support a role of MRs in the regulation of the HPA axis under basal conditions as well as in response to stress. The increased availability of cortisol after spironolactone treatment implies enhanced GR activation, which, in combination with MR blockade, presumably resulted in a decreased MR/GR activation ratio. This condition influences both selective attention and performance in various memory tasks.

Colocalization of corticotropin-releasing hormone and oestrogen receptor-alpha in the paraventricular nucleus of the hypothalamus in mood disorders

NARCIS (Netherlands)

Bao, Ai-Min; Hestiantoro, Andon; van Someren, Eus J. W.; Swaab, Dick F.; Zhou, Jiang-Ning

2005-01-01

Oestrogens may modulate the activity of the hypothalamic-pituitary-adrenal (HPA) axis. The present study was to investigate whether the activity of the HPA axis in mood disorders might be directly modulated by oestrogens via oestrogen receptors (ORs) in the corticotropin-releasing hormone (CRH)

Hepatic macrophage complement receptor clearance function following injury.

Science.gov (United States)

Cuddy, B G; Loegering, D J; Blumenstock, F A; Shah, D M

1986-03-01

Previous work has demonstrated that in vivo hepatic macrophage complement receptor clearance function is depressed following thermal injury. The present study was carried out to determine if complement receptor function depression is associated with other states of depressed host defense. Hepatic complement receptor clearance function was determined from the hepatic uptake of rat erythrocytes coated with antierythrocyte IgM (EIgM) in rats. Receptor function was determined following cannulation of a carotid artery, laparotomy plus enterotomy, hemorrhagic shock, trauma, thermal injury, acute bacteremia, acute endotoxemia, and injection of erythrocyte stroma, gelatinized lipid emulsion, or colloidal carbon. Hepatic uptake of EIgM was depressed following each of these experimental interventions except arterial cannulation. This effect was shown not to be due to a decrease in hepatic blood flow or depletion of complement and was therefore due to a depression in hepatic macrophage complement receptor clearance function. Thus, impairment of hepatic macrophage complement receptor function is associated with several states of depressed host defense.

Acute stress-induced sensitization of the pituitary-adrenal response to heterotypic stressors: independence of glucocorticoid release and activation of CRH1 receptors.

Science.gov (United States)

Belda, Xavier; Daviu, Núria; Nadal, Roser; Armario, Antonio

2012-09-01

A single exposure to some severe stressors causes sensitization of the hypothalamic-pituitary-adrenal (HPA) response to novel stressors. However, the putative factors involved in stress-induced sensitization are not known. In the present work we studied in adult male rats the possible role of glucocorticoids and CRH type 1 receptor (CRH-R1), using an inhibitor of glucocorticoid synthesis (metyrapone, MET), the glucocorticoid receptor (GR) antagonist RU38486 (mifepristone) and the non-peptide CRH-R1 antagonist R121919. In a first experiment we demonstrated with different doses of MET (40-150 mg/kg) that the highest dose acted as a pharmacological stressor greatly increasing ACTH release and altering the normal circadian pattern of HPA hormones, but no dose affected ACTH responsiveness to a novel environment as assessed 3 days after drug administration. In a second experiment, we found that MET, at a dose (75 mg/kg) that blocked the corticosterone response to immobilization (IMO), did not alter IMO-induced ACTH sensitization. Finally, neither the GR nor the CRH-R1 antagonists blocked IMO-induced ACTH sensitization on the day after IMO. Thus, a high dose of MET, in contrast to IMO, was unable to sensitize the HPA response to a novel environment despite the huge activation of the HPA axis caused by the drug. Neither a moderate dose of MET that markedly reduced corticosterone response to IMO, nor the blockade of GR or CRH-R1 receptors was able to alter stress-induced HPA sensitization. Therefore, stress-induced sensitization is not the mere consequence of a marked HPA activation and does not involve activation of glucocorticoid or CRH-R1 receptors. Copyright © 2012 Elsevier Inc. All rights reserved.

Brain catalase activity inhibition as well as opioid receptor antagonism increases ethanol-induced HPA axis activation.

Science.gov (United States)

Pastor, Raúl; Sanchis-Segura, Carles; Aragon, Carlos M G

2004-12-01

Growing evidence indicates that brain catalase activity is involved in the psychopharmacological actions of ethanol. Recent data suggest that participation of this enzymatic system in some ethanol effects could be mediated by the endogenous opioid system. The present study assessed whether brain catalase has a role in ethanol-induced activation of the HPA axis, a neuroendocrine system modulated by the endogenous opioid neurotransmission. Swiss male mice received an intraperitoneal injection of the catalase inhibitor 3-amino-1,2,4-triazole (AT; 0-1 g/kg), and 0 to 20 hr after this administration, animals received an ethanol (0-4 g/kg; intraperitoneally) challenge. Thirty, 60, or 120 min after ethanol administration, plasma corticosterone levels were determined immunoenzymatically. In addition, we tested the effects of 45 mg/kg of cyanamide (another catalase inhibitor) and 0 to 2 mg/kg of naltrexone (nonselective opioid receptor antagonist) on ethanol-induced enhancement in plasma corticosterone values. The present study revealed that AT boosts ethanol-induced increase in plasma corticosterone levels in a dose- and time-dependent manner. However, it did not affect corticosterone values when measured after administration of saline, cocaine (4 mg/kg, intraperitoneally), or morphine (30 mg/kg, intraperitoneally). The catalase inhibitor cyanamide (45 mg/kg, intraperitoneally) also increased ethanol-related plasma corticosterone levels. These effects of AT and cyanamide on ethanol-induced corticosterone values were observed under treatment conditions that decreased significantly brain catalase activity. Indeed, a significant correlation between effects of catalase manipulations on both variables was found. Finally, we found that the administration of naltrexone enhanced the levels of plasma corticosterone after the administration of saline or ethanol. This study shows that the inhibition of brain catalase increases ethanol-induced plasma corticosterone levels. Results are

Alterations in HPA-axis and autonomic nervous system functioning in childhood anxiety disorders point to a chronic stress hypothesis

NARCIS (Netherlands)

Dieleman, G.C.; Huizink, A.C.; Tulen, J.H.M.; Utens, E.M.W.J.; Creemers, H.E.; van der Ende, J.; Verhulst, F.C.

2015-01-01

Background: It is of debate whether or not childhood anxiety disorders (AD) can be captured by one taxonomic construct. This study examined whether perceived arousal (PA), autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) axis measures can distinguish children with different

Alterations in HPA-axis and autonomic nervous system functioning in childhood anxiety disorders point to a chronic stress hypothesis

NARCIS (Netherlands)

Dieleman, Gwendolyn C.; Huizink, Anja C.; Tulen, Joke H. M.; Utens, Elisabeth M. W. J.; Creemers, Hanneke E.; van der Ende, Jan; Verhulst, Frank C.

2015-01-01

It is of debate whether or not childhood anxiety disorders (AD) can be captured by one taxonomic construct. This study examined whether perceived arousal (PA), autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) axis measures can distinguish children with different primary

Modeling and molecular dynamics of HPA-1a and -1b polymorphisms: effects on the structure of the β3 subunit of the αIIbβ3 integrin.

Directory of Open Access Journals (Sweden)

Vincent Jallu

Full Text Available The HPA-1 alloimmune system carried by the platelet integrin αIIbβ3 is the primary cause of alloimmune thrombocytopenia in Caucasians and the HPA-1b allele might be a risk factor for thrombosis. HPA-1a and -1b alleles are defined by a leucine and a proline, respectively, at position 33 in the β3 subunit. Although the structure of αIIbβ3 is available, little is known about structural effects of the L33P substitution and its consequences on immune response and integrin functions.A complete 3D model of the L33-β3 extracellular domain was built and a P33 model was obtained by in silico mutagenesis. We then performed molecular dynamics simulations. Analyses focused on the PSI, I-EGF-1, and I-EGF-2 domains and confirmed higher exposure of residue 33 in the L33 β3 form. These analyses also showed major structural flexibility of all three domains in both forms, but increased flexibility in the P33 β3 form. The L33P substitution does not alter the local structure (residues 33 to 35 of the PSI domain, but modifies the structural equilibrium of the three domains.These results provide a better understanding of HPA-1 epitopes complexity and alloimmunization prevalence of HPA-1a. P33 gain of structure flexibility in the β3 knee may explain the increased adhesion capacity of HPA-1b platelets and the associated thrombotic risk. Our study provides important new insights into the relationship between HPA-1 variants and β3 structure that suggest possible effects on the alloimmune response and platelet function.

In Obesity, HPA Axis Activity Does Not Increase with BMI, but Declines with Aging: A Meta-Analysis of Clinical Studies.

Directory of Open Access Journals (Sweden)

Judit Tenk

Full Text Available Obesity is one of the major public health challenges worldwide. It involves numerous endocrine disorders as etiological factors or as complications. Previous studies strongly suggested the involvement of the hypothalamic-pituitary-adrenal (HPA axis activity in obesity, however, to date, no consistent trend in obesity-associated alterations of the HPA axis has been identified. Aging has been demonstrated to aggravate obesity and to induce abnormalities of the HPA axis. Thus, the question arises whether obesity is correlated with peripheral indicators of HPA function in adult populations.We aimed to meta-analyze literature data on peripheral cortisol levels as indicators of HPA activity in obesity during aging, in order to identify possible explanations for previous contradictory findings and to suggest new approaches for future clinical studies.3,596 records were identified through searching of PubMed, Embase and Cochrane Library Database. Altogether 26 articles were suitable for analyses.Empirical research papers were eligible provided that they reported data of healthy adult individuals, included body mass index (BMI and measured at least one relevant peripheral cortisol parameter (i.e., either morning blood cortisol or 24-h urinary free cortisol.We used random effect models in each of the meta-analyses calculating with the DerSimonian and Laird weighting methods. I-squared indicator and Q test were performed to assess heterogeneity. Meta-regression was applied to explore the effect of BMI and age on morning blood and urinary free cortisol levels. To assess publication bias Egger's test was used.Obesity did not show any correlation with the studied peripheral cortisol values. On the other hand, peripheral cortisol levels declined with aging within the obese, but not in the non-obese groups.Our analysis demonstrated that obesity or healthy aging does not lead to enhanced HPA axis activity, peripheral cortisol levels rather decline with aging.

In Obesity, HPA Axis Activity Does Not Increase with BMI, but Declines with Aging: A Meta-Analysis of Clinical Studies.

Science.gov (United States)

Tenk, Judit; Mátrai, Péter; Hegyi, Péter; Rostás, Ildikó; Garami, András; Szabó, Imre; Solymár, Margit; Pétervári, Erika; Czimmer, József; Márta, Katalin; Mikó, Alexandra; Füredi, Nóra; Párniczky, Andrea; Zsiborás, Csaba; Balaskó, Márta

2016-01-01

Obesity is one of the major public health challenges worldwide. It involves numerous endocrine disorders as etiological factors or as complications. Previous studies strongly suggested the involvement of the hypothalamic-pituitary-adrenal (HPA) axis activity in obesity, however, to date, no consistent trend in obesity-associated alterations of the HPA axis has been identified. Aging has been demonstrated to aggravate obesity and to induce abnormalities of the HPA axis. Thus, the question arises whether obesity is correlated with peripheral indicators of HPA function in adult populations. We aimed to meta-analyze literature data on peripheral cortisol levels as indicators of HPA activity in obesity during aging, in order to identify possible explanations for previous contradictory findings and to suggest new approaches for future clinical studies. 3,596 records were identified through searching of PubMed, Embase and Cochrane Library Database. Altogether 26 articles were suitable for analyses. Empirical research papers were eligible provided that they reported data of healthy adult individuals, included body mass index (BMI) and measured at least one relevant peripheral cortisol parameter (i.e., either morning blood cortisol or 24-h urinary free cortisol). We used random effect models in each of the meta-analyses calculating with the DerSimonian and Laird weighting methods. I-squared indicator and Q test were performed to assess heterogeneity. Meta-regression was applied to explore the effect of BMI and age on morning blood and urinary free cortisol levels. To assess publication bias Egger's test was used. Obesity did not show any correlation with the studied peripheral cortisol values. On the other hand, peripheral cortisol levels declined with aging within the obese, but not in the non-obese groups. Our analysis demonstrated that obesity or healthy aging does not lead to enhanced HPA axis activity, peripheral cortisol levels rather decline with aging.

Association of a variable number of tandem repeats (VNTR) in glycoprotein Ib alpha and HPA-2 alloantigens

NARCIS (Netherlands)

Simsek, S.; Bleeker, P. M.; van der Schoot, C. E.; von dem Borne, A. E.

1994-01-01

The human platelet alloantigen HPA-2(Koa/Kob) system is involved in two clinical syndromes, neonatal alloimmune thrombocytopenia and platelet transfusion refractoriness. We have previously described that the human platelet alloantigens HPA-2a(Kob) and HPA-2b(Koa), are caused by a Thr145Met amino

Compensation for HPA nonlinearity and I/Q imbalance in MIMO beamforming systems

KAUST Repository

Qi, Jian; Aissa, Sonia

2010-01-01

In this paper, we investigate the effects of high-power amplifier (HPA) nonlinearity and in-phase and quadrature-phase (I/Q) imbalance on the performance of multiple-input multiple-output (MIMO) transmit beamforming (TB) systems. Specifically, we propose a compensation method for HPA nonlinearity and I/Q imbalance together in MIMO TB systems. The performance of the MIMO TB system under study is evaluated in terms of the average symbol error probability (SEP) and system capacity, considering transmission over uncorrelated frequency-flat Rayleigh fading channels. Numerical results are provided and show the effects of several system parameters, such as the HPA parameters, image-leakage ratio, numbers of transmit and receive antennas, length of pilot symbols, and modulation order of phase-shift keying (PSK), on performance. © 2010 IEEE.

Compensation for HPA nonlinearity and I/Q imbalance in MIMO beamforming systems

KAUST Repository

Qi, Jian

2010-10-01

In this paper, we investigate the effects of high-power amplifier (HPA) nonlinearity and in-phase and quadrature-phase (I/Q) imbalance on the performance of multiple-input multiple-output (MIMO) transmit beamforming (TB) systems. Specifically, we propose a compensation method for HPA nonlinearity and I/Q imbalance together in MIMO TB systems. The performance of the MIMO TB system under study is evaluated in terms of the average symbol error probability (SEP) and system capacity, considering transmission over uncorrelated frequency-flat Rayleigh fading channels. Numerical results are provided and show the effects of several system parameters, such as the HPA parameters, image-leakage ratio, numbers of transmit and receive antennas, length of pilot symbols, and modulation order of phase-shift keying (PSK), on performance. © 2010 IEEE.

Daily Parental Knowledge of Youth Activities Is Linked to Youth Physical Symptoms and HPA functioning

Science.gov (United States)

Lippold, Melissa A.; Davis, Kelly D.; McHale, Susan M.; Almeida, David M.

2015-01-01

Considerable evidence documents linkages between parental knowledge of youth activities and youth risky behavior. We extended this research to determine whether parental knowledge was associated with youth physical health, including reports of physical symptoms (e.g., headaches, stomachaches) and a biomarker of hypothalamic pituitary adrenocortical (HPA) axis functioning (i.e., salivary cortisol levels). Participants were children of employees in the Information Technology division of a Fortune 500 company (N = 132, Mean Age Youth = 13.39 years, 55% female) who participated in a daily diary study. Data were collected via telephone calls on eight consecutive evenings. On four study days, cortisol samples were collected at 4 time points (waking, 30 min after waking, before dinner, bedtime). Multi-level models revealed that, at the between-person level, youth whose parents had higher average knowledge about their activities, exhibited lower bedtime cortisol levels. Furthermore, at the within-person level, on days when parents displayed more knowledge than usual (relative to their own eight-day average), youth had lower before-dinner cortisol than usual. Linkages between average parental knowledge and physical health symptoms were moderated by youth age: Younger but not older adolescents whose parents were more knowledgeable had fewer physical health symptoms, on average. A next step is to identify the processes that underlie these associations. PMID:26751757

Contribution of glucocorticoids and glucocorticoid receptors to the regulation of neurodegenerative processes.

Science.gov (United States)

Vyas, Sheela; Maatouk, Layal

2013-12-01

Isolation of glucocorticoids (GCs) from adrenal glands followed by synthesis led rapidly to their first clinical application, about 70 years ago, for treatment of rheumatoid arthritis. To this day GCs are used in diseases that have an inflammatory component. However, their use is carefully monitored because of harmful side effects. GCs are also synonymous with stress and adaptation. In CNS, GC binds and activates high affinity mineralocorticoid receptor (MR) and low affinity glucocorticoid receptor (GR). GR, whose expression is ubiquitous, is only activated when GC levels rise as during circadian peak and in response to stress. Numerous recent studies have yielded important and new insights on the mechanisms concerning pulsatile secretory pattern of GCs as well as various processes that tightly control their synthesis via hypothalamic-pituitary-adrenal (HPA) axis involving regulated release of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) from hypothalamus and pituitary, respectively. GR modulates neuronal functions and viability through both genomic and non-genomic actions, and importantly its transcriptional regulatory activity is tightly locked with GC secretory pattern. There is increasing evidence pointing to involvement of GC-GR in neurodegenerative disorders. Patients with Alzheimer's or Parkinson's or Huntington's disease show chronically high cortisol levels suggesting changes occurring in controls of HPA axis. In experimental models of these diseases, chronic stress or GC treatment was found to exacerbate both the clinical symptoms and neurodegenerative processes. However, recent evidence also shows that GC-GR can exert neuroprotective effects. Thus, for any potential therapeutic strategies in these neurodegenerative diseases we need to understand the precise modifications both in HPA axis and in GR activity and find ways to harness their protective actions.

HPA axis reactivity to pharmacologic and psychological stressors in euthymic women with histories of postpartum versus major depression.

Science.gov (United States)

Ferguson, Elizabeth H; Di Florio, Arianna; Pearson, Brenda; Putnam, Karen T; Girdler, Susan; Rubinow, David R; Meltzer-Brody, Samantha

2017-06-01

It is unclear whether women with a history of postpartum depression (PPD) have residual, abnormal hypothalamic-pituitary-adrenal (HPA) axis reactivity, as has been reported in major depression (MDD). Further unclear is whether the abnormalities in HPA axis reactivity associated with MDD represent a stable, underlying predisposition or a state-dependent phenomenon. This study sought the following: (1) to determine if euthymic postpartum women with a history of depression have an abnormal HPA axis reactivity to pharmacologic and psychological challenges and (2) to compare HPA reactivity in women with histories of PPD versus MDD. As a secondary objective, we wanted to determine the influence of trauma history on HPA axis function. Forty-five parous (12-24 months postpartum), euthymic women with history of MDD (n = 15), PPD (n = 15), and controls (n = 15) completed pharmacologic (dexamethasone/corticotropin-releasing hormone (CRH) test [DEX/CRH]) and psychological (Trier social stress test [TSST]) challenges during the luteal phase. Outcome measures were cortisol and adrenocorticotropic hormone (ACTH) response after DEX/CRH, and blood pressure, heart rate, epinephrine, norepinephrine, and cortisol response during the TSST. All groups had robust cortisol and ACTH response to DEX/CRH and cortisol response to TSST. Groups did not differ significantly in cortisol or ACTH response to DEX/CRH or in blood pressure, heart rate, epinephrine, norepinephrine, or cortisol response to TSST. Cortisol/ACTH ratio did not differ significantly between groups. Trauma history was associated with decreased cortisol response to DEX/CRH in women with histories of MDD, which was not significant after correction (F 8,125 , p = 0.02, Greenhouse-Geisser corrected p = 0.11). Currently euthymic women with histories of MDD or PPD did not demonstrate residual abnormal stress responsivity following administration of either a pharmacologic or psychological stressor.

Orexin receptor expression in the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes of free-living European beavers (Castor fiber L.) in different periods of the reproductive cycle.

Science.gov (United States)

Czerwinska, Joanna; Chojnowska, Katarzyna; Kaminski, Tadeusz; Bogacka, Iwona; Smolinska, Nina; Kaminska, Barbara

2017-01-01

Orexins are hypothalamic neuropeptides acting via two G protein-coupled receptors in mammals: orexin receptor 1 (OX1R) and orexin receptor 2 (OX2R). In European beavers, which are seasonally breeding animals, the presence and functions of orexins and their receptors remain unknown. Our study aimed to determine the expression of OXR mRNAs and the localization of OXR proteins in hypothalamic-pituitary-adrenal/gonadal (HPA/HPG) axes in free-living beavers. The expression of OXR genes (OX1R, OX2R) and proteins was found in all analysed tissues during three periods of beavers' reproductive cycle (April, July, November). The expression of OXR mRNAs in the beaver HPA axis varied seasonally (Ppituitary and adrenals, OX1R mRNA levels were relatively constant in females and peaked in July in males (P<0.05), whereas the OX2R was most highly expressed in males in November and in females in April (P<0.05). In gonads, OX1R expression did not fluctuate between seasons or sexes, but transcript levels were elevated in the testes in November and in the ovaries in July (P<0.05). In turn, OX2R mRNA levels varied between the sexes (P<0.05) and were higher in females (July and November) than in males (P<0.05). The circannual variations in OXR mRNA levels in HPA and HPG axes suggest that the expression of these receptors is associated with sex-specific changes in beavers' reproductive activity and their environmental adaptations. Copyright © 2016 Elsevier Inc. All rights reserved.

Hyperactivity of Hypothalamic-Pituitary-Adrenal Axis Due to Dysfunction of the Hypothalamic Glucocorticoid Receptor in Sigma-1 Receptor Knockout Mice

Directory of Open Access Journals (Sweden)

Tingting Di

2017-09-01

Full Text Available Sigma-1 receptor knockout (σ1R-KO mice exhibit a depressive-like phenotype. Because σ1R is highly expressed in the neuronal cells of hypothalamic paraventricular nuclei (PVN, this study investigated the influence of σ1R deficiency on the regulation of the hypothalamic-pituitary-adrenocortical (HPA axis. Here, we show that the levels of basal serum corticosterone (CORT, adrenocorticotropic hormone (ACTH and corticotrophin releasing factor (CRF as well as the level of CRF mRNA in PVN did not significantly differ between adult male σ1R-KO mice and wild-type (WT mice. Acute mild restraint stress (AMRS induced a higher and more sustainable increase in activity of HPA axis and CRF expression in σ1R-KO mice. Percentage of dexamethasone (Dex-induced reduction in level of CORT was markedly attenuated in σ1R−/− mice. The levels of glucocorticoid receptor (GR and protein kinase C (PKC phosphorylation were reduced in the PVN of σ1R-KO mice and σ1R antagonist NE100-treated WT mice. The exposure to AMRS in σ1R-KO mice induced a stronger phosphorylation of cAMP-response element binding protein (CREB in PVN than that in WT mice. Intracerebroventricular (i.c.v. injection of PKC activator PMA for 3 days in σ1R-KO mice not only recovered the GR phosphorylation and the percentage of Dex-reduced CORT but also corrected the AMRS-induced hyperactivity of HPA axis and enhancement of CRF mRNA and CREB phosphorylation. Furthermore, the injection (i.c.v. of PMA in σ1R-KO mice corrected the prolongation of immobility time in forced swim test (FST and tail suspension test (TST. These results indicate that σ1R deficiency causes down-regulation of GR by reducing PKC phosphorylation, which attenuates GR-mediated feedback inhibition of HPA axis and facilitates the stress response of HPA axis leading to the production of depressive-like behaviors.

NMDA receptor function during senescence: implication on cognitive performance

Directory of Open Access Journals (Sweden)

Ashok eKumar

2015-12-01

Full Text Available N-methyl-D-aspartate (NMDA receptors, a family of L-glutamate receptors, play an important role in learning and memory, and are critical for spatial memory. These receptors are tetrameric ion channels composed of a family of related subunits. One of the hallmarks of the aging human population is a decline in cognitive function; studies in the past couple of years have demonstrated deterioration in NMDA receptor subunit expression and function with advancing age. However, a direct relationship between impaired memory function and a decline in NMDA receptors is still ambiguous. Recent studies indicate a link between an age-associated NMDA receptor hypofunction and memory impairment and provide evidence that age-associated enhanced oxidative stress might be contributing to the alterations associated with senescence. However, clear evidence is still deficient in demonstrating the underlying mechanisms and a relationship between age-associated impaired cognitive faculties and NMDA receptor hypofunction. The current review intends to present an overview of the research findings regarding changes in expression of various NMDA receptor subunits and deficits in NMDA receptor function during senescence and its implication in age-associated impaired hippocampal-dependent memory function.

N-glycosylation of the β2 adrenergic receptor regulates receptor function by modulating dimerization.

Science.gov (United States)

Li, Xiaona; Zhou, Mang; Huang, Wei; Yang, Huaiyu

2017-07-01

N-glycosylation is a common post-translational modification of G-protein-coupled receptors (GPCRs). However, it remains unknown how N-glycosylation affects GPCR signaling. β 2 adrenergic receptor (β 2 AR) has three N-glycosylation sites: Asn6, Asn15 at the N-terminus, and Asn187 at the second extracellular loop (ECL2). Here, we show that deletion of the N-glycan did not affect receptor expression and ligand binding. Deletion of the N-glycan at the N-terminus rather than Asn187 showed decreased effects on isoproterenol-promoted G-protein-dependent signaling, β-arrestin2 recruitment, and receptor internalization. Both N6Q and N15Q showed decreased receptor dimerization, while N187Q did not influence receptor dimerization. As decreased β 2 AR homodimer accompanied with reduced efficiency for receptor function, we proposed that the N-glycosylation of β 2 AR regulated receptor function by influencing receptor dimerization. To verify this hypothesis, we further paid attention to the residues at the dimerization interface. Studies of Lys60 and Glu338, two residues at the receptor dimerization interface, exhibited that the K60A/E338A showed decreased β 2 AR dimerization and its effects on receptor signaling were similar to N6Q and N15Q, which further supported the importance of receptor dimerization for receptor function. This work provides new insights into the relationship among glycosylation, dimerization, and function of GPCRs. Peptide-N-glycosidase F (PNGase F, EC 3.2.2.11); endo-β-N-acetylglucosaminidase A (Endo-A, EC 3.2.1.96). © 2017 Federation of European Biochemical Societies.

Dynamic mobility of functional GABAA receptors at inhibitory synapses.

Science.gov (United States)

Thomas, Philip; Mortensen, Martin; Hosie, Alastair M; Smart, Trevor G

2005-07-01

Importing functional GABAA receptors into synapses is fundamental for establishing and maintaining inhibitory transmission and for controlling neuronal excitability. By introducing a binding site for an irreversible inhibitor into the GABAA receptor alpha1 subunit channel lining region that can be accessed only when the receptor is activated, we have determined the dynamics of receptor mobility between synaptic and extrasynaptic locations in hippocampal pyramidal neurons. We demonstrate that the cell surface GABAA receptor population shows no fast recovery after irreversible inhibition. In contrast, after selective inhibition, the synaptic receptor population rapidly recovers by the import of new functional entities within minutes. The trafficking pathways that promote rapid importation of synaptic receptors do not involve insertion from intracellular pools, but reflect receptor diffusion within the plane of the membrane. This process offers the synapse a rapid mechanism to replenish functional GABAA receptors at inhibitory synapses and a means to control synaptic efficacy.

Combined receptor antagonist stimulation of the hypothalamic-pituitary-adrenal axis test identifies impaired negative feedback sensitivity to cortisol in obese men.

Science.gov (United States)

Mattsson, Cecilia; Reynolds, Rebecca M; Simonyte, Kotryna; Olsson, Tommy; Walker, Brian R

2009-04-01

Hypothalamic-pituitary-adrenal (HPA) axis dysregulation may underlie disorders including obesity, depression, cognitive decline, and the metabolic syndrome. Conventional tests of HPA axis negative feedback rely on glucocorticoid receptor (GR) agonists such as dexamethasone but do not test feedback by endogenous cortisol, potentially mediated by both GR and mineralocorticoid receptors (MR). The objective of the study was to use a combination of GR (RU38486, mifepristone) and MR (spironolactone) antagonists to explore the poorly understood activation of the HPA axis that occurs in obesity. This was a double-blind, placebo-controlled, randomized, crossover study. The study was conducted at a clinical research facility. Participants included 15 lean (body mass index 22.0 +/- 1.6 kg/m(2)) and 16 overweight/obese (body mass index 30.1 +/- 3.5 kg/m(2)) men. Subjects attended on four occasions for blood and saliva sampling every 30 min between 1800 and 2200 h. At 1100 and 1600 h before visits, subjects took 200 mg spironolactone, 400 mg RU38486, 200 mg spironolactone + 400 mg RU38486, or placebo orally. Serum cortisol levels after drug or placebo were measured. Cortisol levels did not differ between lean and obese after placebo. Spironolactone and RU38486 alone had modest effects, increasing cortisol by less than 50% in both groups. However, combined spironolactone plus RU38486 elevated cortisol concentrations substantially, more so in lean than obese men [2.9- (0.3) vs. 2.2 (0.3)-fold elevation, P = 0.002]. Combined receptor antagonist stimulation of the HPA axis reveals redundancy of MR and GR in negative feedback in humans. Obese men have impaired responses to combined receptor antagonist stimulation, suggesting impaired negative feedback by endogenous cortisol. Such an approach may be useful to dissect abnormal HPA axis control in neuropsychiatric and other disorders.

Frequency of anti-glycoprotein Ia/IIa (anti-HPA-5b,-5a and anti-glycoprotein IIb/IIIa (anti-HPA-1a,-3a,-4a alloantibodies in multiparous women of African descent

Directory of Open Access Journals (Sweden)

Zaccheaus A Jeremiah

2010-05-01

Full Text Available Zaccheaus A Jeremiah1, Justina E Oburu2, Osaro Erhabor1, Fiekumo I Buseri1, Teddy C Adias31Haematology and Blood Transfusion Science Unit, Department of Medical Laboratory Sciences, College of Health Sciences, Niger Delta University, Wilberforce Island, Nigeria; 2Department of Haematology and Blood Transfusion, University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria; 3Rivers State University of Science and Technology, Port Harcourt, NigeriaBackground: Human platelet antibodies are often implicated in some disease conditions, such as neonatal alloimmune thrombocytopenia (NAIT, idiopathic thrombocytopenic purpura (ITP and platelet refractoriness. The frequencies of these alloantibodies have not been reported in Nigeria and West Africa.Methods: Screening for allontibodies to human platelet antigens (HPA was undertaken using the GTI PakPlus® qualitative solid phase ELISA reagent. Platelet count was done using the ICSH approved procedure using 1% ammonium oxalate reagent.Study design: A cross-section of apparently healthy adult Nigerian multiparous non-pregnant women, who were staff of a tertiary health facility in the Niger Delta, Nigeria, were screened for alloantibodies to human platelet antigens.Results: Of the one hundred (100 women screened, the prevalence of anti-glycoprotein IIb/IIIa (anti-HPA-Ia,-3a,-4a was zero percent (0%, anti-glycoprotein Ia/IIa (anti-HPA-5b accounted for 30% of results, while anti-glycoprotein Ia/IIa (anti-HPA-5a was 18%. Parity was found to exert significant influence on the development to HPA antibodies (Fisher’s Exact Test = 11.683, P < 0.05; 13.577, P < 0.01. The platelet count of the women did not appear to exert any influence on the development of the antibodies (P > 0.05.Conclusion: This study has observed a high prevalence of anti-HPA-5b in our sample population. The prevalence of alloantibodies to HPA antigens was found to associate strongly with parity. These results indicate that there is a

HPA and SAM axis responses as correlates of self- vs parental ratings of anxiety in boys with an Autistic Disorder.

Science.gov (United States)

Bitsika, Vicki; Sharpley, Christopher F; Sweeney, John A; McFarlane, James R

2014-03-29

Anxiety and Autistic Disorder (AD) are both neurological conditions and both disorders share some features that make it difficult to precisely allocate specific symptoms to each disorder. HPA and SAM axis activities have been conclusively associated with anxiety, and may provide a method of validating anxiety rating scale assessments given by parents and their children with AD about those children. Data from HPA axis (salivary cortisol) and SAM axis (salivary alpha amylase) responses were collected from a sample of 32 high-functioning boys (M age=11yr) with an Autistic Disorder (AD) and were compared with the boys' and their mothers' ratings of the boys' anxiety. There was a significant difference between the self-ratings given by the boys and ratings given about them by their mothers. Further, only the boys' self-ratings of their anxiety significantly predicted the HPA axis responses and neither were significantly related to SAM axis responses. Some boys showed cortisol responses which were similar to that previously reported in children who had suffered chronic and severe anxiety arising from stressful social interactions. As well as suggesting that some boys with an AD can provide valid self-assessments of their anxiety, these data also point to the presence of very high levels of chronic HPA-axis arousal and consequent chronic anxiety in these boys. Copyright © 2014 Elsevier Inc. All rights reserved.

The antidepressant fluoxetine normalizes the nuclear glucocorticoid receptor evoked by psychosocial stress

Science.gov (United States)

Mitić, M.; Simić, I.; Djordjević, J.; Radojčić, M. B.; Adžić, M.

2011-12-01

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the pathophysiology of depression and stress disorders. Glucocorticoids, key regulators of the stress response, exert diverse effects on cellular processes in the hippocampus. Beside non-genomic pathways, glucocorticoid effects are mediated through activation of the glucocorticoid receptor (GR), a ligand activated transcriptional factor that belongs to the nuclear hormone receptor superfamily. We analysed the GR protein levels both in the cytoplasmic and nuclear compartments of the hippocampus of Wistar rats exposed to chronic psychosocial isolation stress upon chronic fluoxetine (FLU) treatment. Under chronic stress, corticosterone levels (CORT) were decreased compared to the control, and treatment with FLU did not change its level in the stressed rats. At the molecular level, FLU normalized the level of nuclear GR protein in the hippocampus of the stressed rats. Discrepancy between normalization of nuclear GR in the hippocampus and lack of normalization of HPA axis activity judged by CORT, suggests that other brain structures such as the amygdale and prefrontal cortex that also regulate HPA axis activity, seem not to be normalized by the FLU treatment used in our study.

Modifications of glucocorticoid receptors mRNA expression in the hypothalamic-pituitary-adrenal axis in response to early-life stress in female Japanese quail.

Science.gov (United States)

Zimmer, C; Spencer, K A

2014-12-01

Stress exposure during early-life development can programme individual brain and physiology. The hypothalamic-pituitary-adrenal (HPA) axis is one of the primary targets of this programming, which is generally associated with a hyperactive HPA axis, indicative of a reduced negative-feedback. This reduced feedback efficiency usually results from a reduced level of the glucocorticoid receptor (GR) and/or the mineralocorticoid receptor (MR) within the HPA axis. However, a few studies have shown that early-life stress exposure results in an attenuated physiological stress response, suggesting an enhance feedback efficiency. In the present study, we aimed to determine whether early-life stress had long-term consequences on GR and MR levels in quail and whether the effects on the physiological response to acute stress observed in prenatally stressed individuals were underpinned by changes in GR and/or MR levels in one or more HPA axis components. We determined GR and MR mRNA expression in the hippocampus, hypothalamus and pituitary gland in quail exposed to elevated corticosterone during prenatal development, postnatal development, or both, and in control individuals exposed to none of the stressors. We showed that prenatal stress increased the GR:MR ratio in the hippocampus, GR and MR expression in the hypothalamus and GR expression in the pituitary gland. Postnatal stress resulted in a reduced MR expression in the hippocampus. Both early-life treatments permanently affected the expression of both receptor types in HPA axis regions. The effects of prenatal stress are in accordance with a more efficient negative-feedback within the HPA axis and thus can explain the attenuated stress response observed in these birds. Therefore, these changes in receptor density or number as a consequence of early-life stress exposure might be the mechanism that allows an adaptive response to later-life stressful conditions. © 2014 The Authors. Journal of Neuroendocrinology published by

Daily parental knowledge of youth activities is linked to youth physical symptoms and HPA functioning.

Science.gov (United States)

Lippold, Melissa A; Davis, Kelly D; McHale, Susan M; Almeida, David M

2016-03-01

Considerable evidence documents linkages between parental knowledge of youth activities and youth risky behavior. We extended this research to determine whether parental knowledge was associated with youth physical health, including reports of physical symptoms (e.g., headaches, stomachaches) and a biomarker of hypothalamic pituitary adrenocortical (HPA) axis functioning (i.e., salivary cortisol levels). Participants were children of employees in the Information Technology division of a Fortune 500 company (N = 132, mean age youth = 13.39 years, 55% female) who participated in a daily diary study. Data were collected via telephone calls on 8 consecutive evenings. On 4 study days, cortisol samples were collected at 4 time points (waking, 30 min after waking, before dinner, bedtime). Multilevel models revealed that, at the between-person level, youth whose parents had higher average knowledge about their activities, exhibited lower bedtime cortisol levels. Furthermore, at the within-person level, on days when parents displayed more knowledge than usual (relative to their own 8-day average), youth had lower before-dinner cortisol than usual. Linkages between average parental knowledge and physical health symptoms were moderated by youth age: Younger but not older adolescents whose parents were more knowledgeable had fewer physical health symptoms, on average. A next step is to identify the processes that underlie these associations. (c) 2016 APA, all rights reserved).

Two-way CSI-assisted AF relaying with HPA nonlinearity

KAUST Repository

Qi, Jian; Aissa, Sonia; Alouiniz, Mohamed-Slim

2015-01-01

In this paper, we investigate half-duplex two-way dual-hop channel state information (CSI)-assisted amplify-andforward (AF) relaying in the presence of high-power amplifier (HPA) nonlinearity at relays. The expression for the end-toend signal

From Malthus to motive: how the HPA axis engineers the phenotype, yoking needs to wants

NARCIS (Netherlands)

Pecoraro, Norman; Dallman, Mary F.; Warne, James P.; Ginsberg, Abigail B.; Laugero, Kevin D.; la Fleur, Susanne E.; Houshyar, Hani; Gomez, Francisca; Bhargava, Aditi; Akana, Susan F.

2006-01-01

The hypothalamo-pituitary-adrenal (HPA) axis is the critical mediator of the vertebrate stress response system, responding to environmental stressors by maintaining internal homeostasis and coupling the needs of the body to the wants of the mind. The HPA axis has numerous complex drivers and highly

Enhanced novelty-induced corticosterone spike and upregulated serotonin 5-HT1A and cannabinoid CB1 receptors in adolescent BTBR mice.

Science.gov (United States)

Gould, Georgianna G; Burke, Teresa F; Osorio, Miguel D; Smolik, Corey M; Zhang, Wynne Q; Onaivi, Emmanuel S; Gu, Ting-Ting; DeSilva, Mauris N; Hensler, Julie G

2014-01-01

Hypothalamic pituitary adrenal (HPA) axis responses to change and social challenges during adolescence can influence mental health and behavior into adulthood. To examine how HPA tone in adolescence may contribute to psychopathology, we challenged male adolescent (5 weeks) and adult (16 weeks) BTBR T(+)tf/J (BTBR) and 129S1/SvImJ (129S) mice with novelty in sociability tests. In prior studies these strains had exaggerated or altered HPA stress responses and low sociability relative to C57BL/6J mice in adulthood. In adolescence these strains already exhibited similar or worse sociability deficits than adults or age-matched C57 mice. Yet BTBR adolescents were less hyperactive and buried fewer marbles than adults. Novelty-induced corticosterone (CORT) spikes in adolescent BTBR were double adult levels, and higher than 129S or C57 mice at either age. Due to their established role in HPA feedback, we hypothesized that hippocampal Gαi/o-coupled serotonin 5-HT1A and cannabinoid CB1 receptor function might be upregulated in BTBR mice. Adolescent BTBR mice had higher hippocampal 5-HT1A density as measured by [(3)H] 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) binding than C57 mice, and adult BTBR 8-OH-DPAT-stimulated GTPγS binding was higher than in either C57 or 129S mice in this region. Further, BTBR hippocampal CB1 density measured by [(3)H]CP55,940 binding was 15-20% higher than in C57. CP55,940-stimulated GTPγS binding in adult BTBR dentate gyrus was 30% higher then 129S (p<0.05), but was not a product of greater neuronal or cell density defined by NeuN and DAPI staining. Hence hyperactive HPA responsiveness during adolescence may underlie 5-HT1A and CB1 receptor up-regulation and behavioral phenotype of BTBR mice. Copyright © 2013 Elsevier Ltd. All rights reserved.

Expression and function of nicotinic acetylcholine receptors in stem cells

Directory of Open Access Journals (Sweden)

Herman S. Cheung

2016-07-01

Full Text Available Nicotinic acetylcholine receptors are prototypical ligand gated ion channels typically found in muscular and neuronal tissues. Functional nicotinic acetylcholine receptors, however, have also recently been identified on other cell types, including stem cells. Activation of these receptors by the binding of agonists like choline, acetylcholine, or nicotine has been implicated in many cellular changes. In regards to stem cell function, nicotinic acetylcholine receptor activation leads to changes in stem cell proliferation, migration and differentiation potential. In this review we summarize the expression and function of known nicotinic acetylcholine receptors in different classes of stem cells including: pluripotent stem cells, mesenchymal stem cells, periodontal ligament derived stem cells, and neural progenitor cells and discuss the potential downstream effects of receptor activation on stem cell function.

Beyond the HPA axis: progesterone-derived neuroactive steroids in human stress and emotion

Directory of Open Access Journals (Sweden)

Michelle eWirth

2011-08-01

Full Text Available Stress and social isolation are well-known risk factors for psychopathology. However, more research is needed as to the physiological mechanisms by which social support buffers the impacts of stress. Research in animal models suggests important roles for progesterone (P and its product, the neuroactive steroid allopregnanolone (ALLO, in stress and psychopathology. These hormones are produced in brain and periphery during stress in rodents, and down-regulate anxiety behavior and HPA axis activity. Human clinical populations, including depressed patients, have alterations in ALLO levels, but it is unclear whether these basal hormone level differences have clinical import. To begin to address this question, this review examines the role of P and ALLO in stress physiology, and the impact of these hormones on mood, in healthy humans. Evidence largely supports that P and ALLO increase during stress in humans. However, P/ALLO administration appears to cause only mild effects on mood and subjective anxiety, while exerting effects consistent with GABA receptor modulation. Additionally, P is linked to motivation for affiliation / social contact; P (and ALLO release may be especially responsive to social rejection. These observations lead to the novel hypothesis that stress-related P/ALLO production functions not only to down-regulate stress and anxiety, but also to promote social contact as a long-term coping strategy. Malfunctioning of the P/ALLO system could therefore underlie depression partly by decreasing propensity to affiliate with others.

Functional reconstitution of the glycine receptor

Energy Technology Data Exchange (ETDEWEB)

Garcia-Calvo, M.; Ruiz-Gomez, A.; Vazquez, J.; Morato, E.; Valdivieso, F.; Mayor, F. Jr. (Universidad Autonoma de Madrid (Spain))

1989-07-25

The functional reconstitution of the chloride channel coupled glycine receptor is described. Glycine receptors were purified from the cholate extract of rat spinal cord membranes by affinity chromatography and incorporated into phospholipid vesicles by the addition of phosphatidylcholine and removal of detergent by gel filtration. The reconstituted vesicles showed the same polypeptide composition as the purified receptor. The pharmacological characteristics of the glycine receptor were also preserved in the proteoliposomes, as demonstrated by the displacement of ({sup 3}H)strychnine binding by several glycinergic ligands and by photoaffinity labeling experiments. In order to observe functional responses (i.e., specific agonist-induced anion translocation), the authors have developed an assay based on the fluorescence quenching of an anion-sensitive entrapped probe, SPQ (6-methoxy-N-(3-sulfopropyl)quinolinium). Reconstituted vesicles were loaded with the fluorescent probe during a freeze-thaw-sonication cycle in the presence of added liposomes containing cholesterol. In such a reconstituted system, glycine receptor agonists are able to increase the rate of anion influx into the vesicles. The action of agonists is blocked by the simultaneous presence of strychnine or other glycine antagonists. The results show that the purified 48,000- and 58,000-dalton polypeptides reconstituted into phospholipid vesicles can bind ligands and promote specific ion translocation in a way similar to the glycine receptor in its native environment.

Hypothalamic-pituitary-adrenal (HPA) axis suppression after treatment with glucocorticoid therapy for childhood acute lymphoblastic leukaemia

NARCIS (Netherlands)

Gordijn, Maartje S.; Gemke, Reinoud J. B. J.; van Dalen, Elvira C.; Rotteveel, Joost; Kaspers, Gertjan J. L.

2012-01-01

Background Glucocorticoids play a major role in the treatment of acute lymphoblastic leukaemia (ALL). However, supraphysiological doses may cause suppression of the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis suppression resulting in reduced cortisol response may cause an impaired stress

Hypothalamic-pituitary-adrenal (HPA) axis suppression after treatment with glucocorticoid therapy for childhood acute lymphoblastic leukaemia

NARCIS (Netherlands)

Gordijn, Maartje S.; Rensen, Niki; Gemke, Reinoud J. B. J.; van Dalen, Elvira C.; Rotteveel, Joost; Kaspers, Gertjan J. L.

2015-01-01

Glucocorticoids play a major role in the treatment of acute lymphoblastic leukaemia (ALL). However, supraphysiological doses can suppress the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis suppression resulting in reduced cortisol response may cause an impaired stress response and an inadequate

Hypothalamic-pituitary-adrenal (HPA) axis suppression after treatment with glucocorticoid therapy for childhood acute lymphoblastic leukaemia

NARCIS (Netherlands)

Rensen, Niki; Gemke, Reinoud J. B. J.; van Dalen, Elvira C.; Rotteveel, Joost; Kaspers, Gertjan J. L.

2017-01-01

Glucocorticoids play a major role in the treatment of acute lymphoblastic leukaemia (ALL). However, supraphysiological doses can suppress the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis suppression resulting in reduced cortisol response may cause an impaired stress response and an inadequate

Palmitoylation as a Functional Regulator of Neurotransmitter Receptors

Directory of Open Access Journals (Sweden)

Vladimir S. Naumenko

2018-01-01

Full Text Available The majority of neuronal proteins involved in cellular signaling undergo different posttranslational modifications significantly affecting their functions. One of these modifications is a covalent attachment of a 16-C palmitic acid to one or more cysteine residues (S-palmitoylation within the target protein. Palmitoylation is a reversible modification, and repeated cycles of palmitoylation/depalmitoylation might be critically involved in the regulation of multiple signaling processes. Palmitoylation also represents a common posttranslational modification of the neurotransmitter receptors, including G protein-coupled receptors (GPCRs and ligand-gated ion channels (LICs. From the functional point of view, palmitoylation affects a wide span of neurotransmitter receptors activities including their trafficking, sorting, stability, residence lifetime at the cell surface, endocytosis, recycling, and synaptic clustering. This review summarizes the current knowledge on the palmitoylation of neurotransmitter receptors and its role in the regulation of receptors functions as well as in the control of different kinds of physiological and pathological behavior.

Functional Analyses of Bitter Taste Receptors in Domestic Cats (Felis catus).

Science.gov (United States)

Lei, Weiwei; Ravoninjohary, Aurore; Li, Xia; Margolskee, Robert F; Reed, Danielle R; Beauchamp, Gary K; Jiang, Peihua

2015-01-01

Cats are obligate carnivores and under most circumstances eat only animal products. Owing to the pseudogenization of one of two subunits of the sweet receptor gene, they are indifferent to sweeteners, presumably having no need to detect plant-based sugars in their diet. Following this reasoning and a recent report of a positive correlation between the proportion of dietary plants and the number of Tas2r (bitter receptor) genes in vertebrate species, we tested the hypothesis that if bitter perception exists primarily to protect animals from poisonous plant compounds, the genome of the domestic cat (Felis catus) should have lost functional bitter receptors and they should also have reduced bitter receptor function. To test functionality of cat bitter receptors, we expressed cat Tas2R receptors in cell-based assays. We found that they have at least 7 functional receptors with distinct receptive ranges, showing many similarities, along with some differences, with human bitter receptors. To provide a comparative perspective, we compared the cat repertoire of intact receptors with those of a restricted number of members of the order Carnivora, with a range of dietary habits as reported in the literature. The numbers of functional bitter receptors in the terrestrial Carnivora we examined, including omnivorous and herbivorous species, were roughly comparable to that of cats thereby providing no strong support for the hypothesis that a strict meat diet influences bitter receptor number or function. Maintenance of bitter receptor function in terrestrial obligate carnivores may be due to the presence of bitter compounds in vertebrate and invertebrate prey, to the necessary role these receptors play in non-oral perception, or to other unknown factors. We also found that the two aquatic Carnivora species examined had fewer intact bitter receptors. Further comparative studies of factors driving numbers and functions of bitter taste receptors will aid in understanding the forces

Imidazoline2 (I2) receptor- and alpha2-adrenoceptor-mediated modulation of hypothalamic-pituitary-adrenal axis activity in control and acute restraint stressed rats.

Science.gov (United States)

Finn, David P; Hudson, Alan L; Kinoshita, Hiroshi; Coventry, Toni L; Jessop, David S; Nutt, David J; Harbuz, Michael S

2004-03-01

Central noradrenaline regulates the activity of the hypothalamic-pituitary-adrenal (HPA) axis and the neuroendocrine response to stress. alpha2-adrenoceptors and imidazoline2 (I2) receptors modulate the activity of the central noradrenergic system. The present set of experiments investigated the role of alpha2-adrenoceptors and I2 receptors in the regulation of HPA axis activity under basal conditions and during exposure to the acute psychological stress of restraint. Three separate experiments were carried out in which rats were given an i.p. injection of either saline vehicle, the combined alpha2-adrenoceptor antagonist and I2 receptor ligand idazoxan (10 mg/kg), the selective I2 receptor ligand BU224 (2.5 or 10 mg/kg) or the selective alpha2-adrenoceptor antagonist RX821002 (2.5 mg/kg) with or without restraint stress. Drugs were administered immediately prior to restraint of 60 min duration. Blood was sampled pre-injection, 30, 60 and 240 min post-injection and plasma corticosterone was measured by radioimmunoassay. In experiment 1, idazoxan increased plasma corticosterone levels in naive animals and potentiated the corticosterone response to acute restraint stress. In experiment 2, BU224 administration increased plasma corticosterone levels in a dose-related manner in naive rats. The results of experiment 3 indicated that RX821002 also elevated plasma corticosterone levels in naive rats, however, only BU224 potentiated the corticosterone response to restraint stress. These studies suggest that both alpha2-adrenoceptors and I2 receptors play a role in modulating basal HPA axis activity and that I2 receptors may play a more important role than alpha2-adrenoceptors in modulating the HPA axis response to the acute psychological stress of restraint.

Adversity-driven changes in hypothalamic-pituitary-adrenal axis functioning during adolescence

NARCIS (Netherlands)

Laceulle, O.M.; Nederhof, Esther; van Aken, M.A.G.; Ormel, Johan

2017-01-01

The hypothalamic-pituitary-adrenal (HPA) axis has been proposed to be a key mechanism underlying the link between adversity and mental health, but longitudinal studies on adversity and HPA-axis functioning are scarce. Here, we studied adversity-driven changes in HPA-axis functioning during

Adolescent development, hypothalamic-pituitary-adrenal function, and programming of adult learning and memory.

Science.gov (United States)

McCormick, Cheryl M; Mathews, Iva Z

2010-06-30

Chronic exposure to stress is known to affect learning and memory in adults through the release of glucocorticoid hormones by the hypothalamic-pituitary-adrenal (HPA) axis. In adults, glucocorticoids alter synaptic structure and function in brain regions that express high levels of glucocorticoid receptors and that mediate goal-directed behaviour and learning and memory. In contrast to relatively transient effects of stress on cognitive function in adulthood, exposure to high levels of glucocorticoids in early life can produce enduring changes through substantial remodeling of the developing nervous system. Adolescence is another time of significant brain development and maturation of the HPA axis, thereby providing another opportunity for glucocorticoids to exert programming effects on neurocircuitry involved in learning and memory. These topics are reviewed, as is the emerging research evidence in rodent models highlighting that adolescence may be a period of increased vulnerability compared to adulthood in which exposure to high levels of glucocorticoids results in enduring changes in adult cognitive function. Copyright 2009 Elsevier Inc. All rights reserved.

Compartmentalization of B-cell antigen receptor functions

NARCIS (Netherlands)

Lankester, A. C.; van Lier, R. A.

1996-01-01

Receptor tyrosine kinases (RTK), like the PDGF-receptor, translate information from the extracellular environment into cytoplasmic signals that regulate a spectrum of cellular functions. RTK molecules consist of ligand binding extracellular domains, cytoplasmic kinase domains and tyrosine

Combined effects of perfluorooctane sulfonate (PFOS) and maternal restraint stress on hypothalamus adrenal axis (HPA) function in the offspring of mice

International Nuclear Information System (INIS)

Ribes, Diana; Fuentes, Silvia; Torrente, Margarita; Colomina, M. Teresa; Domingo, Jose L.

2010-01-01

Although it is known that prenatal exposure to perfluorooctane sulfonate (PFOS) can cause developmental adverse effects in mammals, the disruptive effects of this compound on hormonal systems are still controversial. Information concerning the effects of PFOS on hypothalamus adrenal (HPA) axis response to stress and corticosterone levels is not currently available. On the other hand, it is well established that stress can enhance the developmental toxicity of some chemicals. In the present study, we assessed the combined effects of maternal restraint stress and PFOS on HPA axis function in the offspring of mice. Twenty plug-positive female mice were divided in two groups. Animals were given by gavage 0 and 6 mg PFOS/kg/day on gestation days 12-18. One half of the animals in each group were also subjected to restraint stress (30 min/session, 3 sessions/day) during the same period. Five plug-positive females were also included as non-manipulated controls. At 3 months of age, activity in an open-field and the stress response were evaluated in male and female mice by exposing them to 30 min of restraint stress. Male and female offspring were subsequently sacrificed and blood samples were collected to measure changes in corticosterone levels at four different moments related to stress exposure conditions: before stress exposure, immediately after 30 min of stress exposure, and recuperation levels at 60 and 90 min after stress exposure. Results indicate corticosterone levels were lower in mice prenatally exposed to restraint. In general terms, PFOS exposure decreased corticosterone levels, although this effect was only significant in females. The recuperation pattern of corticosterone was mainly affected by prenatal stress. Interactive effects between PFOS and maternal stress were sex dependent. The current results suggest that prenatal PFOS exposure induced long-lasting effects in mice.

Sweet Taste Receptor Signaling Network: Possible Implication for Cognitive Functioning

Directory of Open Access Journals (Sweden)

Menizibeya O. Welcome

2015-01-01

Full Text Available Sweet taste receptors are transmembrane protein network specialized in the transmission of information from special “sweet” molecules into the intracellular domain. These receptors can sense the taste of a range of molecules and transmit the information downstream to several acceptors, modulate cell specific functions and metabolism, and mediate cell-to-cell coupling through paracrine mechanism. Recent reports indicate that sweet taste receptors are widely distributed in the body and serves specific function relative to their localization. Due to their pleiotropic signaling properties and multisubstrate ligand affinity, sweet taste receptors are able to cooperatively bind multiple substances and mediate signaling by other receptors. Based on increasing evidence about the role of these receptors in the initiation and control of absorption and metabolism, and the pivotal role of metabolic (glucose regulation in the central nervous system functioning, we propose a possible implication of sweet taste receptor signaling in modulating cognitive functioning.

Functional Analyses of Bitter Taste Receptors in Domestic Cats (Felis catus.

Directory of Open Access Journals (Sweden)

Weiwei Lei

Full Text Available Cats are obligate carnivores and under most circumstances eat only animal products. Owing to the pseudogenization of one of two subunits of the sweet receptor gene, they are indifferent to sweeteners, presumably having no need to detect plant-based sugars in their diet. Following this reasoning and a recent report of a positive correlation between the proportion of dietary plants and the number of Tas2r (bitter receptor genes in vertebrate species, we tested the hypothesis that if bitter perception exists primarily to protect animals from poisonous plant compounds, the genome of the domestic cat (Felis catus should have lost functional bitter receptors and they should also have reduced bitter receptor function. To test functionality of cat bitter receptors, we expressed cat Tas2R receptors in cell-based assays. We found that they have at least 7 functional receptors with distinct receptive ranges, showing many similarities, along with some differences, with human bitter receptors. To provide a comparative perspective, we compared the cat repertoire of intact receptors with those of a restricted number of members of the order Carnivora, with a range of dietary habits as reported in the literature. The numbers of functional bitter receptors in the terrestrial Carnivora we examined, including omnivorous and herbivorous species, were roughly comparable to that of cats thereby providing no strong support for the hypothesis that a strict meat diet influences bitter receptor number or function. Maintenance of bitter receptor function in terrestrial obligate carnivores may be due to the presence of bitter compounds in vertebrate and invertebrate prey, to the necessary role these receptors play in non-oral perception, or to other unknown factors. We also found that the two aquatic Carnivora species examined had fewer intact bitter receptors. Further comparative studies of factors driving numbers and functions of bitter taste receptors will aid in

EURAMET.M.P-S9: comparison in the negative gauge pressure range -950 to 0 hPa

Science.gov (United States)

Saxholm, S.; Otal, P.; AltintaS, A.; Bermanec, L. G.; Durgut, Y.; Hanrahan, R.; Kocas, I.; Lefkopoulos, A.; Pražák, D.; Sandu, I.; Åetina, J.; Spohr, I.; Steindl, D.; Tammik, K.; Testa, N.

2016-01-01

A comparison in the negative gauge pressure range was arranged in the period 2011 - 2012. A total of 14 laboratories participated in this comparison: BEV (Austria), CMI (Czech Republic), DANIAmet-FORCE (Denmark), EIM (Greece), HMI/FSB-LPM (Croatia), INM (Romania), IPQ (Portugal), LNE (France), MCCAA (Malta), METROSERT (Estonia), MIKES (Finland), MIRS/IMT/LMT (Slovenia), NSAI (Ireland) and UME (Turkey). The project was divided into two loops: Loop1, piloted by MIKES, and Loop2, piloted by LNE. The results of the two loops are reported separately: Loop1 results are presented in this paper. The transfer standard was Beamex MC5 no. 25516865 with internal pressure module INT1C, resolution 0.01 hPa. The nominal pressure range of the INT1C is -1000 hPa to +1000 hPa. The nominal pressure points for the comparison were 0 hPa, -200 hPa, -400 hPa, -600 hPa, -800 hPa and -950 hPa. The reference values and their uncertainties as well as the difference uncertainty between the laboratory results and the reference values were determined from the measurement data by Monte Carlo simulations. Stability uncertainty of the transfer standard was included in the final difference uncertainty. Degrees of equivalences and mutual equivalences between the laboratories were calculated. Each laboratory reported results for all twelve measurement points, which means that there were 168 reported values in total. Some 163 of the 168 values (97 %) agree with the reference values within the expanded uncertainties, with a coverage factor k = 2. Among the laboratories, four different methods were used to determine negative gauge pressure. It is concluded that special attention must be paid to the measurements and methods when measuring negative gauge pressures. There might be a need for a technical guide or a workshop that provides information about details and practices related to the measurements of negative gauge pressure, as well as differences between the different methods. The comparison is

Stress and Cognition: the relevance of timing, steroid receptors and sex differences

NARCIS (Netherlands)

Cornelisse, S.

2013-01-01

In response to a stressful situation the autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) axis are activated, eventually leading to the release of catecholamines and corticosteroids. These stress hormones bind to different receptors in the brain (in case of corticosteroids,

Pharmacology and function of melatonin receptors

International Nuclear Information System (INIS)

Dubocovich, M.L.

1988-01-01

The hormone melatonin is secreted primarily from the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone, through an action in the brain, appears to be involved in the regulation of various neural and endocrine processes that are cued by the daily change in photoperiod. This article reviews the pharmacological characteristics and function of melatonin receptors in the central nervous system, and the role of melatonin in mediating physiological functions in mammals. Melatonin and melatonin agonists, at picomolar concentrations, inhibit the release of dopamine from retina through activation of a site that is pharmacologically different from a serotonin receptor. These inhibitory effects are antagonized by the novel melatonin receptor antagonist luzindole (N-0774), which suggests that melatonin activates a presynaptic melatonin receptor. In chicken and rabbit retina, the pharmacological characteristics of the presynaptic melatonin receptor and the site labeled by 2-[125I]iodomelatonin are identical. It is proposed that 2-[125I]iodomelatonin binding sites (e.g., chicken brain) that possess the pharmacological characteristics of the retinal melatonin receptor site (order of affinities: 2-iodomelatonin greater than 6-chloromelatonin greater than or equal to melatonin greater than or equal to 6,7-di-chloro-2-methylmelatonin greater than 6-hydroxymelatonin greater than or equal to 6-methoxymelatonin greater than N-acetyltryptamine greater than or equal to luzindole greater than N-acetyl-5-hydroxytryptamine greater than 5-methoxytryptamine much greater than 5-hydroxytryptamine) be classified as ML-1 (melatonin 1). The 2-[125I]iodomelatonin binding site of hamster brain membranes possesses different binding and pharmacological characteristics from the retinal melatonin receptor site and should be classified as ML-2. 64 references

A translational approach to clinical practice via stress-responsive glucocorticoid receptor signaling.

Science.gov (United States)

Juruena, Mario F; Agustini, Bruno; Cleare, Anthony J; Young, Allan H

2017-01-01

A recent article by Kwan and colleagues could elegantly demonstrate the necessary interaction between neuronal serotonin (5-HT) systems and the hypothalamic-pituitary-adrenal (HPA) axis through glucocorticoid receptors (GR), producing an adequate stress response, in this case, responding to hypoxia with an increase in hematopoietic stem and progenitor cells (HSPC). There is an intricate system connecting brain, body and mind and this exchange is only possible when all these systems-nervous, endocrine, and immune-have receptors on critical cells to receive information (via messenger molecules) from each of the other systems. There is evidence that the expression and function of GR in the hippocampus, mainly MR, is regulated by the stimulation of 5-HT receptors. Stressful stimuli increase 5-HT release and turnover in the hippocampus, and it seems reasonable to suggest that some of the changes in mineralocorticoid and GR expression may be mediated, in part at least, by the increase in 5-HT. Also serotonin and HPA axis dysfunctions have already been implicated in a variety of psychiatric disorders, especially depression. Early life stress (ELS) can have profound impact on these systems and can predispose subjects to a variety of adult metabolic and psychiatric conditions. It is important to analyze the mechanisms of this complex interaction and its subsequent programming effects on the stress systems, so that we can find new ways and targets for treatment of psychiatric disorders. Different areas of research on basic biological sciences are now being integrated and this approach will hopefully provide several new insights, new pharmacological targets and improve our global understanding of these highly debilitating chronic conditions, that we now call mental disorders.

NCS-1 associates with adenosine A2A receptors and modulates receptor function

Directory of Open Access Journals (Sweden)

Gemma eNavarro

2012-04-01

Full Text Available Modulation of G protein-coupled receptor (GPCR signalling by local changes in intracellular calcium concentration is an established function of Calmodulin which is known to interact with many GPCRs. Less is known about the functional role of the closely related neuronal EF-hand Ca2+-sensor proteins that frequently associate with calmodulin targets with different functional outcome. In the present study we aimed to investigate if a target of calmodulin – the A2A adenosine receptor, is able to associate with two other neuronal calcium binding proteins, namely NCS-1 and caldendrin. Using bioluminescence resonance energy transfer and co-immunoprecipitation experiments we show the existence of A2A - NCS-1 complexes in living cells whereas caldendrin did not associate with A2A receptors under the conditions tested. Interestingly, NCS-1 binding modulated downstream A2A receptor intracellular signalling in a Ca2+-dependent manner. Taken together this study provides further evidence that neuronal Ca2+-sensor proteins play an important role in modulation of GPCR signalling.

Adenosine Receptors in Developing and Adult Mouse Neuromuscular Junctions and Functional Links With Other Metabotropic Receptor Pathways.

Science.gov (United States)

Tomàs, Josep; Garcia, Neus; Lanuza, Maria A; Santafé, Manel M; Tomàs, Marta; Nadal, Laura; Hurtado, Erica; Simó-Ollé, Anna; Cilleros-Mañé, Víctor; Just-Borràs, Laia

2018-01-01

In the last few years, we have studied the presence and involvement in synaptogenesis and mature transmitter release of the adenosine autoreceptors (AR) in the mammalian neuromuscular junction (NMJ). Here, we review and bring together the previously published data to emphasize the relevance of these receptors for developmental axonal competition, synaptic loss and mature NMJ functional modulation. However, in addition to AR, activity-dependent mediators originating from any of the three cells that make the synapse (nerve, muscle, and glial cells) cross the extracellular cleft to generate signals in target metabotropic receptors. Thus, the integrated interpretation of the complementary function of all these receptors is needed. We previously studied, in the NMJ, the links of AR with mAChR and the neurotrophin receptor TrkB in the control of synapse elimination and transmitter release. We conclude that AR cooperate with these receptors through synergistic and antagonistic effects in the developmental synapse elimination process. In the adult NMJ, this cooperation is manifested so as that the functional integrity of a given receptor group depends on the other receptors operating normally (i.e., the functional integrity of mAChR depends on AR operating normally). These observations underlie the relevance of AR in the NMJ function.

Adenosine Receptors in Developing and Adult Mouse Neuromuscular Junctions and Functional Links With Other Metabotropic Receptor Pathways

Directory of Open Access Journals (Sweden)

Josep Tomàs

2018-04-01

Full Text Available In the last few years, we have studied the presence and involvement in synaptogenesis and mature transmitter release of the adenosine autoreceptors (AR in the mammalian neuromuscular junction (NMJ. Here, we review and bring together the previously published data to emphasize the relevance of these receptors for developmental axonal competition, synaptic loss and mature NMJ functional modulation. However, in addition to AR, activity-dependent mediators originating from any of the three cells that make the synapse (nerve, muscle, and glial cells cross the extracellular cleft to generate signals in target metabotropic receptors. Thus, the integrated interpretation of the complementary function of all these receptors is needed. We previously studied, in the NMJ, the links of AR with mAChR and the neurotrophin receptor TrkB in the control of synapse elimination and transmitter release. We conclude that AR cooperate with these receptors through synergistic and antagonistic effects in the developmental synapse elimination process. In the adult NMJ, this cooperation is manifested so as that the functional integrity of a given receptor group depends on the other receptors operating normally (i.e., the functional integrity of mAChR depends on AR operating normally. These observations underlie the relevance of AR in the NMJ function.

Plant growth enhancement and associated physiological responses are coregulated by ethylene and gibberellin in response to harpin protein Hpa1.

Science.gov (United States)

Li, Xiaojie; Han, Bing; Xu, Manyu; Han, Liping; Zhao, Yanying; Liu, Zhilan; Dong, Hansong; Zhang, Chunling

2014-04-01

The harpin protein Hpa1 produced by the bacterial blight pathogen of rice induces several growth-promoting responses in plants, activating the ethylene signaling pathway, increasing photosynthesis rates and EXPANSIN (EXP) gene expression levels, and thereby enhancing the vegetative growth. This study was attempted to analyze any mechanistic connections among the above and the role of gibberellin in these responses. Hpa1-induced growth enhancement was evaluated in Arabidopsis, tomato, and rice. And growth-promoting responses were determined mainly as an increase of chlorophyll a/b ratio, which indicates a potential elevation of photosynthesis rates, and enhancements of photosynthesis and EXP expression in the three plant species. In Arabidopsis, Hpa1-induced growth-promoting responses were partially compromised by a defect in ethylene perception or gibberellin biosynthesis. In tomato and rice, compromises of Hpa1-induced growth-promoting responses were caused by a pharmacological treatment with an ethylene perception inhibitor or a gibberellin biosynthesis inhibitor. In the three plant species, moreover, Hpa1-induced growth-promoting responses were significantly impaired, but not totally eliminated, by abolishing ethylene perception or gibberellin synthesis. However, simultaneous nullifications in both ethylene perception and gibberellin biosynthesis almost canceled the full effects of Hpa1 on plant growth, photosynthesis, and EXP2 expression. Theses results suggest that ethylene and gibberellin coregulate Hpa1-induced plant growth enhancement and associated physiological and molecular responses.

Fluorescence Imaging of Streptococcus pneumoniae with the Helix pomatia agglutinin (HPA As a Potential, Rapid Diagnostic Tool

Directory of Open Access Journals (Sweden)

Mirian Domenech

2017-07-01

Full Text Available Streptococcus pneumoniae is a common human pathogen and a major causal agent of life-threatening infections that can either be respiratory or non-respiratory. It is well known that the Helix pomatia (edible snail agglutinin (HPA lectin shows specificity for terminal αGalNAc residues present, among other locations, in the Forssman pentasaccharide (αGalNAc1→3βGalNAc1→3αGal1→4βGal1→4βGlc. Based on experiments involving choline-independent mutants and different growth conditions, we propose here that HPA recognizes the αGalNAc terminal residues of the cell wall teichoic and lipoteichoic acids of S. pneumoniae. In addition, experimental evidence showing that pneumococci can be specifically labeled with HPA when growing as planktonic cultures as well as in mixed biofilms of S. pneumoniae and Haemophilus influenzae has been obtained. It should be underlined that pneumococci were HPA-labeled despite of the presence of a capsule. Although some non-pneumococcal species also bind the agglutinin, HPA-binding combined with fluorescence microscopy constitutes a suitable tool for identifying S. pneumoniae and, if used in conjunction with Gram staining and/or other suitable technique like antigen detection, it may potentially facilitate a fast and accurate diagnosis of pneumococcal infections.

Identification of anti-HPA-1a allo-antibodies using IgG platelet antibody detection and crossmatch system assay with Galileo Echo.

Science.gov (United States)

Di Cristofaro, Julie; Frassati, Coralie; Montagnie, Rolande; Basire, Agnes; Merieux, Yves; Picard, Christophe

2015-01-01

Fetal/neonatal allo-immune thrombocytopenia is the most frequent and the most dangerous clinical condition involving anti-human platelet antigens (HPA)-1a allo-antibodies. Anti-HPA-1a allo-immunization requires rapid and accurate diagnosis to determine appropriate treatment. The Capture-P Ready-Screen assay (C-PRS) is a new qualitative immunoassay to detect IgG anti-human leukocyte antigen (HLA) and anti-HPA allo-antibodies. The aim of this study is to assess the identification of anti-HPA-1a allo-antibodies using the C-PRS assay, associated with HLA class I stripping reagents, on the automated benchtop analyzer Galileo Echo. Forty-nine sera were analyzed: without anti-HLA class I or anti-HPA allo-antibodies, with anti-HLA class I allo-antibodies, with anti-HPA-1a allo-antibodies, among which with anti-HLA class I allo-antibodies. None of the samples without allo-antibodies were reactive. Only anti-HLA antibodies, detected by cytotoxicity-dependent complement and not by Luminex, remained positive before and after stripping reagents. Of the 13 samples, anti-HPA-1a allo-antibodies that were correctly identified before and after incubation with HLA assassin reagent were 70% and 85%, respectively. Anti-glycoprotein auto-antibodies and anti-HLA allo-antibodies do not interfere with the detection of anti-HPA-1a antibodies. This preliminary study indicates that further improvement of the test will be helpful in developing a clinically useful assay in the future.

Functionally biased signalling properties of 7TM receptors - opportunities for drug development for the ghrelin receptor

DEFF Research Database (Denmark)

Sivertsen, B; Holliday, N; Madsen, A N

2013-01-01

UNLABELLED: The ghrelin receptor is a 7 transmembrane (7TM) receptor involved in a variety of physiological functions including growth hormone secretion, increased food intake and fat accumulation as well as modulation of reward and cognitive functions. Because of its important role in metabolism...... and energy expenditure, the ghrelin receptor has become an important therapeutic target for drug design and the development of anti-obesity compounds. However, none of the compounds developed so far have been approved for commercial use. Interestingly, the ghrelin receptor is able to signal through several...... review, we have described how ligands and mutations in the 7TM receptor may bias the receptors to favour either one G-protein over another or to promote G-protein independent signalling pathways rather than G-protein-dependent pathways. For the ghrelin receptor, both agonist and inverse agonists have...

Internalization of G-protein-coupled receptors: Implication in receptor function, physiology and diseases.

Science.gov (United States)

Calebiro, Davide; Godbole, Amod

2018-04-01

G protein-coupled receptors (GPCRs) are the largest family of membrane receptors and mediate the effects of numerous hormones and neurotransmitters. The nearly 1000 GPCRs encoded by the human genome regulate virtually all physiological functions and are implicated in the pathogenesis of prevalent human diseases such as thyroid disorders, hypertension or Parkinson's disease. As a result, 30-50% of all currently prescribed drugs are targeting these receptors. Once activated, GPCRs induce signals at the cell surface. This is often followed by internalization, a process that results in the transfer of receptors from the plasma membrane to membranes of the endosomal compartment. Internalization was initially thought to be mainly implicated in signal desensitization, a mechanism of adaptation to prolonged receptor stimulation. However, several unexpected functions have subsequently emerged. Most notably, accumulating evidence indicates that internalization can induce prolonged receptor signaling on intracellular membranes, which is apparently required for at least some biological effects of hormones like TSH, LH and adrenaline. These findings reveal an even stronger connection between receptor internalization and signaling than previously thought. Whereas new studies are just beginning to reveal an important physiological role for GPCR signaling after internalization and ways to exploit it for therapeutic purposes, future investigations will be required to explore its involvement in human disease. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stress responsiveness of the hypothalamic-pituitary-adrenal axis: age-related features of the vasopressinergic regulation

Directory of Open Access Journals (Sweden)

Nadezhda Dmitrievna Goncharova

2013-03-01

Full Text Available The hypothalamic-pituitary-adrenal (HPA axis plays a key role in adaptation to environmental stresses. Parvicellular neurons of the hypothalamic paraventricular nucleus secrete corticotrophin releasing hormone (CRH and arginine vasopressin (AVP into pituitary portal system; CRH and AVP stimulate ACTH release through specific G protein-coupled membrane receptors on pituitary corticotrophs, CRH1 for CRH and V1b for AVP; the adrenal gland cortex secretes glucocorticoids in response ACTH. The glucocorticoids activate specific receptors in brain and peripheral tissues thereby triggering the necessary metabolic, immune, neuromodulatory and behavioral changes to resist stress. While importance of CRH, as a key hypothalamic factor of HPA axis regulation in basal and stress conditions in most species, is generally recognized, role of AVP remains to be clarified. This review focuses on the role of AVP in the regulation of stress responsiveness of the HPA axis with emphasis on the effects of aging on vasopressinergic regulation of HPA axis stress responsiveness. Under most of the known stressors, AVP is necessary for acute ACTH secretion but in a context-specific manner. The current data on the AVP role in regulation of HPA responsiveness to chronic stress in adulthood are rather contradictory. The importance of the vasopressinergic regulation of the HPA stress responsiveness is greatest during fetal development, in neonatal period, and in the lactating adult. Aging associated with increased variability in several parameters of HPA function including basal state, responsiveness to stressors, and special testing. Reports on the possible role of the AVP/V1b receptor system in the increase of HPA axis hyperactivity with aging are contradictory and requires further research. Many contradictory results may be due to age and species differences in the HPA function of rodents and primates.

Emotional exhaustion and overcommitment to work are differentially associated with hypothalamus-pituitary-adrenal (HPA) axis responses to a low-dose ACTH1-24 (Synacthen) and dexamethasone-CRH test in healthy school teachers.

Science.gov (United States)

Wolfram, Maren; Bellingrath, Silja; Feuerhahn, Nicolas; Kudielka, Brigitte M

2013-01-01

Evidence for a detrimental impact of chronic work stress on health has accumulated in epidemiological research. Recent studies indicate altered hypothalamus-pituitary-adrenal (HPA) axis regulation as a possible biological pathway underlying the link between stress and disease. However, the direction of dysregulation remains unclear, with reported HPA hyper- or hyporeactivity. To disentangle potential effects on different functional levels in the HPA axis, we examined responses using two pharmacological stimulation tests in 53 healthy teachers (31 females, 22 males; mean age: 49.3 years; age range: 30-64 years): a low-dose adrenocorticotrophic hormone (ACTH(1-24), Synacthen) test was used to assess adrenal cortex sensitivity and the combined dexamethasone-corticotropin releasing hormone (DEX-CRH) test to examine pituitary and adrenal cortex reactivity. Blood and saliva samples were collected at - 1,+15,+30,+45,+60,+90,+120 min. Emotional exhaustion (EE), the core dimension of burnout, was measured with the Maslach Burnout Inventory. Overcommitment (OC) was assessed according to Siegrist's effort-reward-imbalance model. We found a significant association between EE and higher plasma cortisol profiles after Synacthen (p = 0.045). By contrast, OC was significantly associated with attenuated ACTH (p = 0.045), plasma cortisol (p = 0.005), and salivary cortisol (p = 0.023) concentrations following DEX-CRH. Results support the notion of altered HPA axis regulation in chronically work-stressed teachers, with differential patterns of hyper- and hyporeactivity depending on individual stress condition and the tested functional level of the HPA axis.

LONGITUDINAL CHANGES IN GLUCOCORTICOID RECEPTOR 1F METHYLATION AND PSYCHOPATHOLOGY AFTER MILITARY DEPLOYMENT

NARCIS (Netherlands)

Schur, Remmelt; Boks, Marco; Rutten, Bart P. F.; Daskalakis, Nikolaos; de Nijs, Laurence; Joels, Marian; Kahn, Rene S.; Geuze, Elbert; Vermetten, Eric; Vinkers, Christiaan

2017-01-01

Background The glucocorticoid receptor (GR) 1F region is involved in transcription and expression of the GR protein and influences hypothalamic-pituitary-adrenal (HPA)-axis activity. Several studies have investigated GR-1F DNA methylation in the context of traumatic stress and psychiatric disorders,

GABA regulates the rat hypothalamic-pituitary-adrenocortical axis via different GABA-A receptor alpha-subtypes

DEFF Research Database (Denmark)

Mikkelsen, Jens D; Bundzikova, Jana; Larsen, Marianne Hald

2008-01-01

dependent on the composition of the GABA-A receptor subunits through which they act. We show here that positive modulators of alpha(1)-subtype containing GABA-A receptors with zolpidem (10 mg/kg) increase HPA activity in terms of increase in plasma corticosterone and induction of Fos in the PVN, whereas...... after positive modulation of GABA-A receptors composed of alpha(1)-subunit(s) affects a selective afferent system than the PVN, which is distinct from another afferent system(s) activated by non alpha(1)-containing GABA-A receptors....

Scavenger Receptor CD163 and Its Biological Functions

Directory of Open Access Journals (Sweden)

Gabriela Onofre

2009-01-01

Full Text Available CD163 is a member of scavenger receptor super family class B of the first subgroup. It is mapped to the region p13 on chromosome 12. Five different isoforms of CD163 have been described, which differ in the structure of their cytoplasmic domains and putative phosporylation sites. This scavenger receptor is selectively expressed on cells of monocytes and macrophages lineage exclusively. CD163 immunological function is essentially homeostatic. It also has other functions because participates in adhesion to endothelial cells, in tolerance induction and tissues regeneration. Other very important function of CD163 is the clearance of hemoglobin in its cell-free form and participation in anti-inflammation in its soluble form, exhibiting cytokine-like functions. We review the biological functions of CD163 which have been discovered until now. It seems apparent from this review that CD163 scavenger receptor can be used as biomarker in different diseases and as a valuable diagnostic parameter for prognosis of many diseases especially inflammatory disorders and sepsis.

Hpa1 harpin needs nitroxyl terminus to promote vegetative growth ...

Indian Academy of Sciences (India)

2016-08-26

Aug 26, 2016 ... Home; Journals; Journal of Biosciences; Volume 39; Issue 1. Hpa1 harpin needs nitroxyl terminus to ... Hansong Dong1 Chunling Zhang1. State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing Agricultural University, Jiangsu, 210095, China ...

Functional relevance of neurotransmitter receptor heteromers in the central nervous system.

Science.gov (United States)

Ferré, Sergi; Ciruela, Francisco; Woods, Amina S; Lluis, Carme; Franco, Rafael

2007-09-01

The existence of neurotransmitter receptor heteromers is becoming broadly accepted and their functional significance is being revealed. Heteromerization of neurotransmitter receptors produces functional entities that possess different biochemical characteristics with respect to the individual components of the heteromer. Neurotransmitter receptor heteromers can function as processors of computations that modulate cell signaling. Thus, the quantitative or qualitative aspects of the signaling generated by stimulation of any of the individual receptor units in the heteromer are different from those obtained during coactivation. Furthermore, recent studies demonstrate that some neurotransmitter receptor heteromers can exert an effect as processors of computations that directly modulate both pre- and postsynaptic neurotransmission. This is illustrated by the analysis of striatal receptor heteromers that control striatal glutamatergic neurotransmission.

Adenosine Receptor Heteromers and their Integrative Role in Striatal Function

Directory of Open Access Journals (Sweden)

Sergi Ferré

2007-01-01

Full Text Available By analyzing the functional role of adenosine receptor heteromers, we review a series of new concepts that should modify our classical views of neurotransmission in the central nervous system (CNS. Neurotransmitter receptors cannot be considered as single functional units anymore. Heteromerization of neurotransmitter receptors confers functional entities that possess different biochemical characteristics with respect to the individual components of the heteromer. Some of these characteristics can be used as a “biochemical fingerprint” to identify neurotransmitter receptor heteromers in the CNS. This is exemplified by changes in binding characteristics that are dependent on coactivation of the receptor units of different adenosine receptor heteromers. Neurotransmitter receptor heteromers can act as “processors” of computations that modulate cell signaling, sometimes critically involved in the control of pre- and postsynaptic neurotransmission. For instance, the adenosine A1-A2A receptor heteromer acts as a concentration-dependent switch that controls striatal glutamatergic neurotransmission. Neurotransmitter receptor heteromers play a particularly important integrative role in the “local module” (the minimal portion of one or more neurons and/or one or more glial cells that operates as an independent integrative unit, where they act as processors mediating computations that convey information from diverse volume-transmitted signals. For instance, the adenosine A2A-dopamine D2 receptor heteromers work as integrators of two different neurotransmitters in the striatal spine module.

Conformational regulation of urokinase receptor function

DEFF Research Database (Denmark)

Gårdsvoll, Henrik; Jacobsen, Benedikte; Kriegbaum, Mette C

2011-01-01

PA per se into the hydrophobic ligand binding cavity of uPAR that modulates the function of this receptor. Based on these data, we now propose a model in which the inherent interdomain mobility in uPAR plays a major role in modulating its function. Particularly one uPAR conformation, which is stabilized...

The psyche and gastric functions.

Science.gov (United States)

Nardone, Gerardo; Compare, Debora

2014-01-01

Although the idea that gastric problems are in some way related to mental activity dates back to the beginning of the last century, until now it has received scant attention by physiologists, general practitioners and gastroenterologists. The major breakthrough in understanding the interactions between the central nervous system and the gut was the discovery of the enteric nervous system (ENS) in the 19th century. ENS (also called 'little brain') plays a crucial role in the regulation of the physiological gut functions. Furthermore, the identification of corticotropin-releasing factor (CRF) and the development of specific CRF receptor antagonists have permitted to characterize the neurochemical basis of the stress response. The neurobiological response to stress in mammals involves three key mechanisms: (1) stress is perceived and processed by higher brain centers; (2) the brain mounts a neuroendocrine response by way of the hypothalamic-pituitary-adrenal axis (HPA) and the autonomic nervous system (ANS), and (3) the brain triggers feedback mechanisms by HPA and ANS stimulation to restore homeostasis. Various stressors such as anger, fear, painful stimuli, as well as life or social learning experiences affect both the individual's physiologic and gastric function, revealing a two-way interaction between brain and stomach. There is overwhelming experimental and clinical evidence that stress influences gastric function, thereby outlining the pathogenesis of gastric diseases such as functional dyspepsia, gastroesophageal reflux disease and peptic ulcer disease. A better understanding of the role of pathological stressors in the modulation of disease activity may have important pathogenetic and therapeutic implications. © 2014 S. Karger AG, Basel.

Non-Neuronal Functions of the M2 Muscarinic Acetylcholine Receptor

Directory of Open Access Journals (Sweden)

Ritva Tikkanen

2013-04-01

Full Text Available Acetylcholine is an important neurotransmitter whose effects are mediated by two classes of receptors. The nicotinic acetylcholine receptors are ion channels, whereas the muscarinic receptors belong to the large family of G protein coupled seven transmembrane helix receptors. Beyond its function in neuronal systems, it has become evident that acetylcholine also plays an important role in non-neuronal cells such as epithelial and immune cells. Furthermore, many cell types in the periphery are capable of synthesizing acetylcholine and express at least some of the receptors. In this review, we summarize the non-neuronal functions of the muscarinic acetylcholine receptors, especially those of the M2 muscarinic receptor in epithelial cells. We will review the mechanisms of signaling by the M2 receptor but also the cellular trafficking and ARF6 mediated endocytosis of this receptor, which play an important role in the regulation of signaling events. In addition, we provide an overview of the M2 receptor in human pathological conditions such as autoimmune diseases and cancer.

Stress in adolescence and drugs of abuse in rodent models: Role of dopamine, CRF, and HPA axis

Science.gov (United States)

Burke, Andrew R.; Miczek, Klaus A.

2014-01-01

Rationale Research on adolescence and drug abuse increased substantially in the past decade. However, drug-addiction related behaviors following stressful experiences during adolescence are less studied. We focus on rodent models of adolescent stress cross-sensitization to drugs of abuse. Objectives Review the ontogeny of behavior, dopamine, corticotropin-releasing factor (CRF), and the hypothalamic pituitary adrenal (HPA) axis in adolescent rodents. We evaluate evidence that stressful experiences during adolescence engender hypersensitivity to drugs of abuse and offer potential neural mechanisms. Results and Conclusions Much evidence suggests that final maturation of behavior, dopamine systems, and HPA axis occurs during adolescence. Stress during adolescence increases amphetamine- and ethanol-stimulated locomotion, preference, and self-administration under many conditions. The influence of adolescent stress on subsequent cocaine- and nicotine-stimulated locomotion and preference is less clear. The type of adolescent stress, temporal interval between stress and testing, species, sex, and the drug tested are key methodological determinants for successful cross-sensitization procedures. The sensitization of the mesolimbic dopamine system is proposed to underlie stress cross-sensitization to drugs of abuse in both adolescents and adults through modulation by CRF. Reduced levels of mesocortical dopamine appear to be a unique consequence of social stress during adolescence. Adolescent stress may reduce the final maturation of cortical dopamine through D2 dopamine receptor regulation of dopamine synthesis or glucocorticoid-facilitated pruning of cortical dopamine fibers. Certain rodent models of adolescent adversity are useful for determining neural mechanisms underlying the cross-sensitization to drugs of abuse. PMID:24370534

BDNF and glucocorticoids regulate corticotrophin-releasing hormone (CRH) homeostasis in the hypothalamus.

Science.gov (United States)

Jeanneteau, Freddy D; Lambert, W Marcus; Ismaili, Naima; Bath, Kevin G; Lee, Francis S; Garabedian, Michael J; Chao, Moses V

2012-01-24

Regulation of the hypothalamic-pituitary-adrenal (HPA) axis is critical for adaptation to environmental changes. The principle regulator of the HPA axis is corticotrophin-releasing hormone (CRH), which is made in the parventricular nucleus and is an important target of negative feedback by glucocorticoids. However, the molecular mechanisms that regulate CRH are not fully understood. Disruption of normal HPA axis activity is a major risk factor of neuropsychiatric disorders in which decreased expression of the glucocorticoid receptor (GR) has been documented. To investigate the role of the GR in CRH neurons, we have targeted the deletion of the GR, specifically in the parventricular nucleus. Impairment of GR function in the parventricular nucleus resulted in an enhancement of CRH expression and an up-regulation of hypothalamic levels of BDNF and disinhibition of the HPA axis. BDNF is a stress and activity-dependent factor involved in many activities modulated by the HPA axis. Significantly, ectopic expression of BDNF in vivo increased CRH, whereas reduced expression of BDNF, or its receptor TrkB, decreased CRH expression and normal HPA functions. We find the differential regulation of CRH relies upon the cAMP response-element binding protein coactivator CRTC2, which serves as a switch for BDNF and glucocorticoids to direct the expression of CRH.

Prenatal stress modifies behavior and hypothalamic-pituitary-adrenal function in female guinea pig offspring: effects of timing of prenatal stress and stage of reproductive cycle.

Science.gov (United States)

Kapoor, Amita; Matthews, Stephen G

2008-12-01

Prenatal stress is associated with altered behavior and hypothalamic-pituitary-adrenal (HPA) axis function postnatally. Recent studies suggest that these outcomes are dependent on the timing of the prenatal stress. The majority of these studies have been carried out in male offspring. We hypothesized that a short period of prenatal stress would result in female offspring that exhibit differences in open-field behavior and HPA axis activity, but the outcome would depend on the timing of the prenatal stress and the stage of the reproductive cycle. Pregnant guinea pigs were exposed to a strobe light during the fetal brain growth spurt [gestational d 50-52 (PS50)] or during the period of rapid brain myelination [gestational d 60-62 (PS60)]. Open-field activity was assessed in juvenile and adult female offspring. HPA axis function was tested in adult offspring. All tests in adulthood were carried out during the estrous and luteal phases of the reproductive cycle to determine the effect of stage on HPA axis programming. Tissues were collected upon completion of the study for analysis by in situ hybridization. PS60 offspring exhibited decreased activity in an open field during the estrous phase of the reproductive cycle compared with control offspring. Both PS50 and PS60 offspring exhibited a lower salivary cortisol response to a stressor, only during the estrous phase. Consistent with the behavioral and endocrine data, PS60 females exhibited lower plasma estradiol levels, reduced ovary weight, and increased glucocorticoid receptor mRNA in the paraventricular nucleus. In conclusion, we have demonstrated that there are effects of prenatal stress on behavior and HPA axis functioning in female offspring but that the outcomes are dependent on the timing of the prenatal stress together with the status of the reproductive cycle.

Expressing exogenous functional odorant receptors in cultured olfactory sensory neurons

Directory of Open Access Journals (Sweden)

Fomina Alla F

2008-09-01

Full Text Available Abstract Background Olfactory discrimination depends on the large numbers of odorant receptor genes and differential ligand-receptor signaling among neurons expressing different receptors. In this study, we describe an in vitro system that enables the expression of exogenous odorant receptors in cultured olfactory sensory neurons. Olfactory sensory neurons in the culture express characteristic signaling molecules and, therefore, provide a system to study receptor function within its intrinsic cellular environment. Results We demonstrate that cultured olfactory sensory neurons express endogenous odorant receptors. Lentiviral vector-mediated gene transfer enables successful ectopic expression of odorant receptors. We show that the ectopically expressed mouse I7 is functional in the cultured olfactory sensory neurons. When two different odorant receptors are ectopically expressed simultaneously, both receptor proteins co-localized in the same olfactory sensory neurons up to 10 days in vitro. Conclusion This culture technique provided an efficient method to culture olfactory sensory neurons whose morphology, molecular characteristics and maturation progression resembled those observed in vivo. Using this system, regulation of odorant receptor expression and its ligand specificity can be studied in its intrinsic cellular environment.

GABA_A receptor function is regulated by lipid bilayer elasticity

DEFF Research Database (Denmark)

Søgaard, Rikke; Werge, Thomas; Berthelsen, Camilla

2006-01-01

( s) underlying these effects are poorly understood. DHA and Triton X-100, at concentrations that affect GABAA receptor function, increase the elasticity of lipid bilayers measured as decreased bilayer stiffness using gramicidin channels as molecular force transducers. We have previously shown...... reduced the peak amplitude of the GABA-induced currents and increased the rate of receptor desensitization. The effects of the amphiphiles did not correlate with the expected changes in monolayer spontaneous curvature. We conclude that GABAA receptor function is regulated by lipid bilayer elasticity....... PUFAs may generally regulate membrane protein function by affecting the elasticity of the host lipid bilayer....

The CCK(-like) receptor in the animal kingdom: functions, evolution and structures.

Science.gov (United States)

Staljanssens, Dorien; Azari, Elnaz Karimian; Christiaens, Olivier; Beaufays, Jérôme; Lins, Laurence; Van Camp, John; Smagghe, Guy

2011-03-01

In this review, the cholecystokinin (CCK)(-like) receptors throughout the animal kingdom are compared on the level of physiological functions, evolutionary basis and molecular structure. In vertebrates, the CCK receptor is an important member of the G-protein coupled receptors as it is involved in the regulation of many physiological functions like satiety, gastrointestinal motility, gastric acid secretion, gall bladder contraction, pancreatic secretion, panic, anxiety and memory and learning processes. A homolog for this receptor is also found in nematodes and arthropods, called CK receptor and sulfakinin (SK) receptor, respectively. These receptors seem to have evolved from a common ancestor which is probably still closely related to the nematode CK receptor. The SK receptor is more closely related to the CCK receptor and seems to have similar functions. A molecular 3D-model for the CCK receptor type 1 has been built together with the docking of the natural ligands for the CCK and SK receptors in the CCK receptor type 1. These molecular models can help to study ligand-receptor interactions, that can in turn be useful in the development of new CCK(-like) receptor agonists and antagonists with beneficial health effects in humans or potential for pest control. Copyright © 2010 Elsevier Inc. All rights reserved.

Do orphan G-protein-coupled receptors have ligand-independent functions? New insights from receptor heterodimers

OpenAIRE

Levoye, Angélique; Dam, Julie; Ayoub, Mohammed A; Guillaume, Jean-Luc; Jockers, Ralf

2006-01-01

G-protein-coupled receptors (GPCRs) are important drug targets and are involved in virtually every biological process. However, there are still more than 140 orphan GPCRs, and deciphering their function remains a priority for fundamental and clinical research. Research on orphan GPCRs has concentrated mainly on the identification of their natural ligands, whereas recent data suggest additional ligand-independent functions for these receptors. This emerging concept is connected with the observ...

Hypothalamic-pituitary-adrenal axis genetic variation and early stress moderates amygdala function.

Science.gov (United States)

Di Iorio, Christina R; Carey, Caitlin E; Michalski, Lindsay J; Corral-Frias, Nadia S; Conley, Emily Drabant; Hariri, Ahmad R; Bogdan, Ryan

2017-06-01

Early life stress may precipitate psychopathology, at least in part, by influencing amygdala function. Converging evidence across species suggests that links between childhood stress and amygdala function may be dependent upon hypothalamic-pituitary-adrenal (HPA) axis function. Using data from college-attending non-Hispanic European-Americans (n=308) who completed the Duke Neurogenetics Study, we examined whether early life stress (ELS) and HPA axis genetic variation interact to predict threat-related amygdala function as well as psychopathology symptoms. A biologically-informed multilocus profile score (BIMPS) captured HPA axis genetic variation (FKBP5 rs1360780, CRHR1 rs110402; NR3C2 rs5522/rs4635799) previously associated with its function (higher BIMPS are reflective of higher HPA axis activity). BOLD fMRI data were acquired while participants completed an emotional face matching task. ELS and depression and anxiety symptoms were measured using the childhood trauma questionnaire and the mood and anxiety symptom questionnaire, respectively. The interaction between HPA axis BIMPS and ELS was associated with right amygdala reactivity to threat-related stimuli, after accounting for multiple testing (empirical-p=0.016). Among individuals with higher BIMPS (i.e., the upper 21.4%), ELS was positively coupled with threat-related amygdala reactivity, which was absent among those with average or low BIMPS. Further, higher BIMPS were associated with greater self-reported anxious arousal, though there was no evidence that amygdala function mediated this relationship. Polygenic variation linked to HPA axis function may moderate the effects of early life stress on threat-related amygdala function and confer risk for anxiety symptomatology. However, what, if any, neural mechanisms may mediate the relationship between HPA axis BIMPS and anxiety symptomatology remains unclear. Copyright © 2017 Elsevier Ltd. All rights reserved.

TAAR1 Modulates Cortical Glutamate NMDA Receptor Function

Science.gov (United States)

Espinoza, Stefano; Lignani, Gabriele; Caffino, Lucia; Maggi, Silvia; Sukhanov, Ilya; Leo, Damiana; Mus, Liudmila; Emanuele, Marco; Ronzitti, Giuseppe; Harmeier, Anja; Medrihan, Lucian; Sotnikova, Tatyana D; Chieregatti, Evelina; Hoener, Marius C; Benfenati, Fabio; Tucci, Valter; Fumagalli, Fabio; Gainetdinov, Raul R

2015-01-01

Trace Amine-Associated Receptor 1 (TAAR1) is a G protein-coupled receptor expressed in the mammalian brain and known to influence subcortical monoaminergic transmission. Monoamines, such as dopamine, also play an important role within the prefrontal cortex (PFC) circuitry, which is critically involved in high-o5rder cognitive processes. TAAR1-selective ligands have shown potential antipsychotic, antidepressant, and pro-cognitive effects in experimental animal models; however, it remains unclear whether TAAR1 can affect PFC-related processes and functions. In this study, we document a distinct pattern of expression of TAAR1 in the PFC, as well as altered subunit composition and deficient functionality of the glutamate N-methyl-D-aspartate (NMDA) receptors in the pyramidal neurons of layer V of PFC in mice lacking TAAR1. The dysregulated cortical glutamate transmission in TAAR1-KO mice was associated with aberrant behaviors in several tests, indicating a perseverative and impulsive phenotype of mutants. Conversely, pharmacological activation of TAAR1 with selective agonists reduced premature impulsive responses observed in the fixed-interval conditioning schedule in normal mice. Our study indicates that TAAR1 plays an important role in the modulation of NMDA receptor-mediated glutamate transmission in the PFC and related functions. Furthermore, these data suggest that the development of TAAR1-based drugs could provide a novel therapeutic approach for the treatment of disorders related to aberrant cortical functions. PMID:25749299

Steroid receptors and their ligands: Effects on male gamete functions

International Nuclear Information System (INIS)

Aquila, Saveria; De Amicis, Francesca

2014-01-01

In recent years a new picture of human sperm biology is emerging. It is now widely recognized that sperm contain nuclear encoded mRNA, mitochondrial encoded RNA and different transcription factors including steroid receptors, while in the past sperm were considered incapable of transcription and translation. One of the main targets of steroid hormones and their receptors is reproductive function. Expression studies on Progesterone Receptor, estrogen receptor, androgen receptor and their specific ligands, demonstrate the presence of these systems in mature spermatozoa as surface but also as nuclear conventional receptors, suggesting that both systemic and local steroid hormones, through sperm receptors, may influence male reproduction. However, the relationship between the signaling events modulated by steroid hormones and sperm fertilization potential as well as the possible involvement of the specific receptors are still controversial issues. The main line of this review highlights the current research in human sperm biology examining new molecular systems of response to the hormones as well as specific regulatory pathways controlling sperm cell fate and biological functions. Most significant studies regarding the identification of steroid receptors are reported and the mechanistic insights relative to signaling pathways, together with the change in sperm metabolism energy influenced by steroid hormones are discussed.The reviewed evidences suggest important effects of Progesterone, Estrogen and Testosterone and their receptors on spermatozoa and implicate the involvement of both systemic and local steroid action in the regulation of male fertility potential. - Highlights: • One of the main targets of steroid hormones and their receptors is reproductive function. • Pg/PR co-work to stimulate enzymatic activities to sustain a capacitation process. • E2/ERs regulate sperm motility, capacitation and acrosome reaction and act as survival factors. • Androgens

Steroid receptors and their ligands: Effects on male gamete functions

Energy Technology Data Exchange (ETDEWEB)

Aquila, Saveria; De Amicis, Francesca, E-mail: francesca.deamicis@unical.it

2014-11-01

In recent years a new picture of human sperm biology is emerging. It is now widely recognized that sperm contain nuclear encoded mRNA, mitochondrial encoded RNA and different transcription factors including steroid receptors, while in the past sperm were considered incapable of transcription and translation. One of the main targets of steroid hormones and their receptors is reproductive function. Expression studies on Progesterone Receptor, estrogen receptor, androgen receptor and their specific ligands, demonstrate the presence of these systems in mature spermatozoa as surface but also as nuclear conventional receptors, suggesting that both systemic and local steroid hormones, through sperm receptors, may influence male reproduction. However, the relationship between the signaling events modulated by steroid hormones and sperm fertilization potential as well as the possible involvement of the specific receptors are still controversial issues. The main line of this review highlights the current research in human sperm biology examining new molecular systems of response to the hormones as well as specific regulatory pathways controlling sperm cell fate and biological functions. Most significant studies regarding the identification of steroid receptors are reported and the mechanistic insights relative to signaling pathways, together with the change in sperm metabolism energy influenced by steroid hormones are discussed.The reviewed evidences suggest important effects of Progesterone, Estrogen and Testosterone and their receptors on spermatozoa and implicate the involvement of both systemic and local steroid action in the regulation of male fertility potential. - Highlights: • One of the main targets of steroid hormones and their receptors is reproductive function. • Pg/PR co-work to stimulate enzymatic activities to sustain a capacitation process. • E2/ERs regulate sperm motility, capacitation and acrosome reaction and act as survival factors. • Androgens

Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS.

Science.gov (United States)

Leonhardt, Julia; Villela, Daniel C; Teichmann, Anke; Münter, Lisa-Marie; Mayer, Magnus C; Mardahl, Maibritt; Kirsch, Sebastian; Namsolleck, Pawel; Lucht, Kristin; Benz, Verena; Alenina, Natalia; Daniell, Nicholas; Horiuchi, Masatsugu; Iwai, Masaru; Multhaup, Gerhard; Schülein, Ralf; Bader, Michael; Santos, Robson A; Unger, Thomas; Steckelings, Ulrike Muscha

2017-06-01

The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may indicate heterodimerization of these receptors. Therefore, this study investigated the molecular and functional interplay between MAS and the AT2R. Molecular interactions were assessed by fluorescence resonance energy transfer and by cross correlation spectroscopy in human embryonic kidney-293 cells transfected with vectors encoding fluorophore-tagged MAS or AT2R. Functional interaction of AT2R and MAS was studied in astrocytes with CX3C chemokine receptor-1 messenger RNA expression as readout. Coexpression of fluorophore-tagged AT2R and MAS resulted in a fluorescence resonance energy transfer efficiency of 10.8 ± 0.8%, indicating that AT2R and MAS are capable to form heterodimers. Heterodimerization was verified by competition experiments using untagged AT2R and MAS. Specificity of dimerization of AT2R and MAS was supported by lack of dimerization with the transient receptor potential cation channel, subfamily C-member 6. Dimerization of the AT2R was abolished when it was mutated at cysteine residue 35. AT2R and MAS stimulation with the respective agonists, Compound 21 or angiotensin-(1-7), significantly induced CX3C chemokine receptor-1 messenger RNA expression. Effects of each agonist were blocked by an AT2R antagonist (PD123319) and also by a MAS antagonist (A-779). Knockout of a single of these receptors made astrocytes unresponsive for both agonists. Our results suggest that MAS and the AT2R form heterodimers and that-at least in astrocytes-both receptors functionally depend on each other. © 2017 American Heart Association, Inc.

Variability in the leptin, leptin receptor and heart fatty acid binding protein genes in relationship with meat quality traits in pigs

Directory of Open Access Journals (Sweden)

Renata Mikolášová

2005-01-01

Full Text Available The leptin (LEP-HinfI, leptin receptor (LEPR-HpaII and heart fatty acid binding protein (H-FABP-HinfI genes and their genotypes combination (LEP-HinfI *LEPR-HpaII were tested for associations with the pH1, pH24, myoglobin content (mg/100 g, intramuscular fat content (% and remission (%. The genotypes were determined in Large White, Landrace and Duroc breeds (n = 106, 56 and 4, respectively. The allele frequencies were: LEP-HinfI: C = 0.133 T = 0.867; LEPR-HpaII: A = 0.331 B = 0.669; H-FABP-HinfI: H = 0.745 h = 0.255. The populations of breeds were in the genetic equilibrium according to the χ2 test in the tested loci. The combinations of LEP-HinfI and LEPR-HpaII were significantly associated with the pH24 and remission. The H-FABP-HinfI locus was significantly associated with intramuscular fat content.

Structural–Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work

Directory of Open Access Journals (Sweden)

Gerd Krause

2017-04-01

Full Text Available The thyroid-stimulating hormone receptor (TSHR is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs. TSHR and its endogenous ligand thyrotropin (TSH are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016 concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other

Structural-Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work.

Science.gov (United States)

Kleinau, Gunnar; Worth, Catherine L; Kreuchwig, Annika; Biebermann, Heike; Marcinkowski, Patrick; Scheerer, Patrick; Krause, Gerd

2017-01-01

The thyroid-stimulating hormone receptor (TSHR) is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs). TSHR and its endogenous ligand thyrotropin (TSH) are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy) or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016) concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other class A GPCRs to

Structural–Functional Features of the Thyrotropin Receptor: A Class A G-Protein-Coupled Receptor at Work

Science.gov (United States)

Kleinau, Gunnar; Worth, Catherine L.; Kreuchwig, Annika; Biebermann, Heike; Marcinkowski, Patrick; Scheerer, Patrick; Krause, Gerd

2017-01-01

The thyroid-stimulating hormone receptor (TSHR) is a member of the glycoprotein hormone receptors, a sub-group of class A G-protein-coupled receptors (GPCRs). TSHR and its endogenous ligand thyrotropin (TSH) are of essential importance for growth and function of the thyroid gland and proper function of the TSH/TSHR system is pivotal for production and release of thyroid hormones. This receptor is also important with respect to pathophysiology, such as autoimmune (including ophthalmopathy) or non-autoimmune thyroid dysfunctions and cancer development. Pharmacological interventions directly targeting the TSHR should provide benefits to disease treatment compared to currently available therapies of dysfunctions associated with the TSHR or the thyroid gland. Upon TSHR activation, the molecular events conveying conformational changes from the extra- to the intracellular side of the cell across the membrane comprise reception, conversion, and amplification of the signal. These steps are highly dependent on structural features of this receptor and its intermolecular interaction partners, e.g., TSH, antibodies, small molecules, G-proteins, or arrestin. For better understanding of signal transduction, pathogenic mechanisms such as autoantibody action and mutational modifications or for developing new pharmacological strategies, it is essential to combine available structural data with functional information to generate homology models of the entire receptor. Although so far these insights are fragmental, in the past few decades essential contributions have been made to investigate in-depth the involved determinants, such as by structure determination via X-ray crystallography. This review summarizes available knowledge (as of December 2016) concerning the TSHR protein structure, associated functional aspects, and based on these insights we suggest several receptor complex models. Moreover, distinct TSHR properties will be highlighted in comparison to other class A GPCRs to

Adversity-driven changes in hypothalamic-pituitary-adrenal axis functioning during adolescence. The trails study.

Science.gov (United States)

Laceulle, Odilia M; Nederhof, Esther; van Aken, Marcel A G; Ormel, Johan

2017-11-01

The hypothalamic-pituitary-adrenal (HPA) axis has been proposed to be a key mechanism underlying the link between adversity and mental health, but longitudinal studies on adversity and HPA-axis functioning are scarce. Here, we studied adversity-driven changes in HPA-axis functioning during adolescence (N=141). HPA-axis functioning (basal cortisol, cortisol awakening response, anticipation of, reaction to and recovery after a stress task) was measured twice, at age 16 and 19. Adversity (i.e., social defeat and loss/illness) since age 16 was measured extensively with the Life Stress Interview at age 19. Adolescents who reported being exposed to social defeat showed increases in basal cortisol (ɳ 2 =0.029) and decreases in reaction to the stress task (ɳ 2 =0.030) from age 16-19, compared to their peers in the loss/illness and no stress group. The current study provides unique longitudinal data on the role of adversity in HPA-axis functioning. Evidence is provided that adversity can affect the body's neuroendocrine response to stress, dependent on the nature of both the HPA-measures and adverse events under study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Changes in 5-HT4 receptor and 5-HT transporter binding in olfactory bulbectomized and glucocorticoid receptor heterozygous mice

DEFF Research Database (Denmark)

Licht, Cecilie L; Kirkegaard, Lisbeth; Zueger, Maha

2010-01-01

. The olfactory bulbectomized mice displayed increased activity in the open field test, a characteristic depression-like feature of this model. After bulbectomy, 5-HT(4) receptor binding was increased in the ventral hippocampus (12%) but unchanged in the dorsal hippocampus, frontal and caudal caudate putamen......]citalopram in two murine models of depression-related states, olfactory bulbectomy and glucocorticoid receptor heterozygous (GR(+/-)) mice. The olfactory bulbectomy model is characterized by 5-HT system changes, while the GR(+/-) mice have a deficit in hypothalamic-pituitary-adrenal (HPA) system control....... Among post hoc analyzed regions, there was a 14% decrease in 5-HT(4) receptor binding in the olfactory tubercles. The 5-HTT binding was unchanged in the hippocampus and caudate putamen of bulbectomized mice but post hoc analysis showed small decreases in lateral septum and lateral globus pallidus...

Effects of early childhood trauma on hypothalamic-pituitary-adrenal (HPA) axis function in patients with Chronic Fatigue Syndrome.

Science.gov (United States)

Kempke, Stefan; Luyten, Patrick; De Coninck, Sarah; Van Houdenhove, Boudewijn; Mayes, Linda C; Claes, Stephan

2015-02-01

There is a paucity of studies that have investigated the assumption that early childhood trauma is associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction in Chronic Fatigue Syndrome (CFS). The current study is the first to simultaneously investigate relationships among early childhood trauma, cortisol activity, and cortisol stress reactivity to psychosocial stress in a sample of well-screened CFS patients. We also examined whether self-critical perfectionism (SCP) plays a mediating role in the potential relationship between early trauma and neurobiological stress responses. A total of 40 female patients diagnosed with CFS were asked to provide morning saliva cortisol samples (after awakening, 30min later, and 1h later) for seven consecutive days as a measure of cortisol activity. In addition, patients were exposed to the Trier Social Stress Test, a well-validated stress test, to investigate the relationship between early childhood trauma and cortisol stress reactivity. Before the start of the study, patients completed the Childhood Trauma Questionnaire-Short form (CTQ-SF) as a measure of early childhood trauma (i.e. sexual, physical and emotional traumatic experiences). SCP was measured with the Depressive Experiences Questionnaire (DEQ). Data were analyzed by calculating several indices of cortisol secretion (i.e. Cortisol Awakening Response and Area Under the Curve). There was no association between early childhood trauma and cortisol as measured over the 7-day period. However, emotional neglect was significantly negatively related to cortisol reactivity in the TSST. SCP did not significantly mediate this association. Findings of this study suggest that emotional neglect is associated with blunted HPA axis reactivity, congruent with the assumption that CFS may reflect loss of adaptability of the neuroendocrine stress response system in at least a subgroup of patients. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dietary Manipulations That Induce Ketosis Activate the HPA Axis in Male Rats and Mice: A Potential Role for Fibroblast Growth Factor-21.

Science.gov (United States)

Ryan, Karen K; Packard, Amy E B; Larson, Karlton R; Stout, Jayna; Fourman, Sarah M; Thompson, Abigail M K; Ludwick, Kristen; Habegger, Kirk M; Stemmer, Kerstin; Itoh, Nobuyuki; Perez-Tilve, Diego; Tschöp, Matthias H; Seeley, Randy J; Ulrich-Lai, Yvonne M

2018-01-01

In response to an acute threat to homeostasis or well-being, the hypothalamic-pituitary-adrenocortical (HPA) axis is engaged. A major outcome of this HPA axis activation is the mobilization of stored energy, to fuel an appropriate behavioral and/or physiological response to the perceived threat. Importantly, the extent of HPA axis activity is thought to be modulated by an individual's nutritional environment. In this study, we report that nutritional manipulations signaling a relative depletion of dietary carbohydrates, thereby inducing nutritional ketosis, acutely and chronically activate the HPA axis. Male rats and mice maintained on a low-carbohydrate high-fat ketogenic diet (KD) exhibited canonical markers of chronic stress, including increased basal and stress-evoked plasma corticosterone, increased adrenal sensitivity to adrenocorticotropin hormone, increased stress-evoked c-Fos immunolabeling in the paraventricular nucleus of the hypothalamus, and thymic atrophy, an indicator of chronic glucocorticoid exposure. Moreover, acutely feeding medium-chain triglycerides (MCTs) to rapidly induce ketosis among chow-fed male rats and mice also acutely increased HPA axis activity. Lastly, and consistent with a growing literature that characterizes the hepatokine fibroblast growth factor-21 (FGF21) as both a marker of the ketotic state and as a key metabolic stress hormone, the HPA response to both KD and MCTs was significantly blunted among mice lacking FGF21. We conclude that dietary manipulations that induce ketosis lead to increased HPA axis tone, and that the hepatokine FGF21 may play an important role to facilitate this effect. Copyright © 2018 Endocrine Society.

In Search of HPA Axis Dysregulation in Child and Adolescent Depression

Science.gov (United States)

Guerry, John D.; Hastings, Paul D.

2011-01-01

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in adults with major depressive disorder is among the most consistent and robust biological findings in psychiatry. Given the importance of the adolescent transition to the development and recurrence of depressive phenomena over the lifespan, it is important to have an integrative…

Functional antagonistic properties of clozapine at the 5-HT3 receptor.

Science.gov (United States)

Hermann, B; Wetzel, C H; Pestel, E; Zieglgänsberger, W; Holsboer, F; Rupprecht, R

1996-08-23

The atypical neuroleptic clozapine is thought to exert its psychopharmacological actions through a variety of neurotransmitter receptors. It binds preferentially to D4 and 5-HT2 receptors; however, little is known on it's interaction with the 5-HT3 receptor. Using a cell line stably expressing the 5-HT3 receptor, whole-cell voltage-clamp analysis revealed functional antagonistic properties of clozapine at low nanomolar concentrations in view of a binding affinity in the upper nanomolar range. Because the concentration of clozapine required for an interaction with the 5-HT3 receptor can be achieved with therapeutical doses, functional antagonistic properties at this ligand-gated ion channel may contribute to its unique psychopharmacological profile.

Escitalopram alters gene expression and HPA axis reactivity in rats following chronic overexpression of corticotropin-releasing factor from the central amygdala

Science.gov (United States)

Flandreau, Elizabeth I.; Bourke, Chase H.; Ressler, Kerry J.; Vale, Wylie W.; Nemeroff, Charles B.; Owens, Michael J.

2013-01-01

Summary We have previously demonstrated that viral-mediated overexpression of corticotropin-releasing factor (CRF) within the central nucleus of the amygdala (CeA) reproduces many of the behavioral and endocrine consequences of chronic stress. The present experiment sought to determine whether administration of the selective serotonin reuptake inhibitor (SSRI) escitalopram reverses the adverse effects of CeA CRF overexpression. In a 2 × 2 design, adult male rats received bilateral infusions of a control lentivirus or a lentivirus in which a portion of the CRF promoter is used to drive increased expression of CRF peptide. Four weeks later, rats were then implanted with an Alzet minipump to deliver vehicle or 10 mg/kg/day escitalopram for a 4-week period of time. The defensive withdrawal (DW) test of anxiety and the sucrose-preference test (SPT) of anhedonia were performed both before and after pump implantation. Additional post-implant behavioral tests included the elevated plus maze (EPM) and social interaction (SI) test. Following completion of behavioral testing, the dexamethasone/CRF test was performed to assess HPA axis reactivity. Brains were collected and expression of HPA axis-relevant transcripts were measured using in situ hybridization. Amygdalar CRF overexpression increased anxiety-like behavior in the DW test at week eight, which was only partially prevented by escitalopram. In both CRF-overexpressing and control groups, escitalopram decreased hippocampal CRF expression while increasing hypothalamic and hippocampal expression of the glucocorticoid receptor (GR). These gene expression changes were associated with a significant decrease in HPA axis reactivity in rats treated with escitalopram. Interestingly, escitalopram increased the rate of weight gain only in rats overexpressing CRF. Overall these data support our hypothesis that amygdalar CRF is critical in anxiety-like behavior; because the antidepressant was unable to reverse behavioral

Novel Functional Properties of Drosophila CNS Glutamate Receptors

Energy Technology Data Exchange (ETDEWEB)

Li, Yan; Dharkar, Poorva; Han, Tae-Hee; Serpe, Mihaela; Lee, Chi-Hon; Mayer, Mark L.

2016-12-01

Phylogenetic analysis reveals AMPA, kainate, and NMDA receptor families in insect genomes, suggesting conserved functional properties corresponding to their vertebrate counterparts. However, heterologous expression of the Drosophila kainate receptor DKaiR1D and the AMPA receptor DGluR1A revealed novel ligand selectivity at odds with the classification used for vertebrate glutamate receptor ion channels (iGluRs). DKaiR1D forms a rapidly activating and desensitizing receptor that is inhibited by both NMDA and the NMDA receptor antagonist AP5; crystallization of the KaiR1D ligand-binding domain reveals that these ligands stabilize open cleft conformations, explaining their action as antagonists. Surprisingly, the AMPA receptor DGluR1A shows weak activation by its namesake agonist AMPA and also by quisqualate. Crystallization of the DGluR1A ligand-binding domain reveals amino acid exchanges that interfere with binding of these ligands. The unexpected ligand-binding profiles of insect iGluRs allows classical tools to be used in novel approaches for the study of synaptic regulation.

The BDNF Val66Met polymorphism affects HPA-axis reactivity to acute stress.

Science.gov (United States)

Alexander, Nina; Osinsky, Roman; Schmitz, Anja; Mueller, Eva; Kuepper, Yvonne; Hennig, Juergen

2010-07-01

Growing evidence suggests that individual differences in HPA-axis reactivity to psychosocial stress are partly due to heritable influences. However, knowledge about the role of specific genetic variants remains very limited to date. Since brain-derived neurotrophic factor (BDNF) not only exhibits neurotrophic actions but is also involved in the regulation of hypothalamic neuropeptides, we investigated the role of a common functional polymorphism within the BDNF gene (BDNF Val66Met) in the context of endocrine and cardiovascular stress reactivity. Healthy male adults (N=100) were genotyped and exposed to a standardized laboratory stress task (Public Speaking). Saliva cortisol and self-reported mood levels were obtained at 6 time points prior to the stressor and during an extended recovery period. Furthermore, heart rate reactivity as an indicator of sympathetic activation was monitored continuously during the experimental procedure. We report a small, but significant effect of the BDNF Val66Met polymorphism on stress reactivity. More precisely, carriers of the met-allele showed a significantly attenuated HPA-axis and cardiovascular reactivity to the psychosocial stressor compared to subjects with the val/val genotype. Furthermore, the diminished physiological response in met-allele carriers was also attended by significantly lower self-reported ratings of perceived stress and nervousness. Our findings of a diminished endocrine and cardiovascular stress response in healthy male adults is consistent with a previously published study and adds further evidence for a crucial role of the BDNF Val66Met polymorphism in the modulation of stress reactivity. Copyright 2010. Published by Elsevier Ltd.

Functional somatostatin receptors on a rat pancreatic acinar cell line

International Nuclear Information System (INIS)

Viguerie, N.; Tahiri-Jouti, N.; Esteve, J.P.; Clerc, P.; Logsdon, C.; Svoboda, M.; Susini, C.; Vaysse, N.; Ribet, A.

1988-01-01

Somatostatin receptors from a rat pancreatic acinar cell line, AR4-2J, were characterized biochemically, structurally, and functionally. Binding of 125 I-[Tyr 11 ]Somatostatin to AR4-2J cells was saturable, exhibiting a single class of high-affinity binding sites with a maximal binding capacity of 258 ± 20 fmol/10 6 cells. Somatostatin receptor structure was analyzed by covalently cross-linking 125 I-[Tyr 11 ]somatostatin to its plasma membrane receptors. Gel electrophoresis and autoradiography of cross-linked proteins revealed a peptide containing the somatostatin receptor. Somatostatin inhibited vasoactive intestinal peptide (VIP)-stimulated adenosine 3',5'-cyclic monophosphate (cAMP) formation in a dose-dependent manner. The concentration of somatostatin that caused half-maximal inhibition of cAMP formation was close to the receptor affinity for somatostatin. Pertussis toxin pretreatment of AR4-2J cells prevented somatostatin inhibition of VIP-stimulated cAMP formation as well as somatostatin binding. The authors conclude that AR4-2J cells exhibit functional somatostatin receptors that retain both specificity and affinity of the pancreatic acinar cell somatostatin receptors and act via the pertussis toxin-sensitive guanine nucleotide-binding protein N i to inhibit adenylate cyclase

EphA2 is a functional receptor for the growth factor progranulin.

Science.gov (United States)

Neill, Thomas; Buraschi, Simone; Goyal, Atul; Sharpe, Catherine; Natkanski, Elizabeth; Schaefer, Liliana; Morrione, Andrea; Iozzo, Renato V

2016-12-05

Although the growth factor progranulin was discovered more than two decades ago, the functional receptor remains elusive. Here, we discovered that EphA2, a member of the large family of Ephrin receptor tyrosine kinases, is a functional signaling receptor for progranulin. Recombinant progranulin bound with high affinity to EphA2 in both solid phase and solution. Interaction of progranulin with EphA2 caused prolonged activation of the receptor, downstream stimulation of mitogen-activated protein kinase and Akt, and promotion of capillary morphogenesis. Furthermore, we found an autoregulatory mechanism of progranulin whereby a feed-forward loop occurred in an EphA2-dependent manner that was independent of the endocytic receptor sortilin. The discovery of a functional signaling receptor for progranulin offers a new avenue for understanding the underlying mode of action of progranulin in cancer progression, tumor angiogenesis, and perhaps neurodegenerative diseases. © 2016 Neill et al.

Glucocorticoid receptor haplotypes conferring increased sensitivity (BclI and N363S) are associated with faster progression of multiple sclerosis

DEFF Research Database (Denmark)

Melief, Jeroen; Koper, Jan W; Endert, Erik

2016-01-01

As high cortisol levels are implicated in suppressed disease activity of multiple sclerosis (MS), glucocorticoid receptor (GR) polymorphisms that affect glucocorticoid (GC) sensitivity may impact on this by changing local immunomodulation or regulation of the hypothalamus-pituitary-adrenal (HPA...

Binge-pattern alcohol exposure during puberty induces long-term changes in HPA axis reactivity.

Directory of Open Access Journals (Sweden)

Magdalena M Przybycien-Szymanska

2011-04-01

Full Text Available Adolescence is a dynamic and important period of brain development however, little is known about the long-term neurobiological consequences of alcohol consumption during puberty. Our previous studies showed that binge-pattern ethanol (EtOH treatment during pubertal development negatively dysregulated the responsiveness of the hypothalamo-pituitary-adrenal (HPA axis, as manifested by alterations in corticotrophin-releasing hormone (CRH, arginine vasopressin (AVP, and corticosterone (CORT during this time period. Thus, the primary goal of this study was to determine whether these observed changes in important central regulators of the stress response were permanent or transient. In this study, juvenile male Wistar rats were treated with a binge-pattern EtOH treatment paradigm or saline alone for 8 days. The animals were left undisturbed until adulthood when they received a second round of treatments consisting of saline alone, a single dose of EtOH, or a second binge-pattern treatment paradigm. The results showed that pubertal binge-pattern EtOH exposure induced striking long-lasting alterations of many HPA axis parameters. Overall, our data provide strong evidence that binge-pattern EtOH exposure during pubertal maturation has long-term detrimental effects for the healthy development of the HPA axis.

mGlu5 Receptor Functional Interactions and Addiction

Directory of Open Access Journals (Sweden)

Robyn eBrown

2012-05-01

Full Text Available The idea of ‘receptor mosaics’ suggests that proteins can form complex and dynamic networks, with respect to time and protein make up, which has the potential to make significant contributions to the diversity and specificity of GPCR signalling, particularly in neuropharmacology, where a few key receptors have been implicated in multiple neurological and psychiatric disorders such as addiction. Metabotropic glutamate type 5 receptors (mGlu5 have been shown to heterodimerise and form complexes with other GPCRs including adenosine A2A and dopamine D2 receptors. mGlu5-containing complexes are found in the striatum, a region of the brain known to be critical for mediating the rewarding and incentive motivational properties of drugs of abuse. Indeed, initial studies indicate a role for mGlu5-containing complexes in rewarding and conditioned effects of drugs, as well as drug-seeking behaviour. This is consistent with the substantial influence that mGlu5 complexes appear to have on striatal function, regulating both GABAergic output of striatopallidal neurons and glutamatergic input from corticostriatal afferents. Given their discrete localization, mGlu5-containing complexes represent a novel way in which to minimize the off-target effects and therefore provide us with an exciting therapeutic avenue for drug discovery efforts. Indeed, the therapeutic targeting of receptor mosaics in a tissue specific or temporal manner (for example, a sub-population of receptors in a ‘pathological state’ has the potential to dramatically reduce detrimental side effects that may otherwise impair vital brain function.

The association of metabotropic glutamate receptor type 5 with the neuronal Ca2+-binding protein 2 modulates receptor function.

Science.gov (United States)

Canela, Laia; Fernández-Dueñas, Víctor; Albergaria, Catarina; Watanabe, Masahiko; Lluís, Carme; Mallol, Josefa; Canela, Enric I; Franco, Rafael; Luján, Rafael; Ciruela, Francisco

2009-10-01

Metabotropic glutamate (mGlu) receptors mediate in part the CNS effects of glutamate. These receptors interact with a large array of intracellular proteins in which the final role is to regulate receptor function. Here, using co-immunoprecipitation and pull-down experiments we showed a close and specific interaction between mGlu(5) receptor and NECAB2 in both transfected human embryonic kidney cells and rat hippocampus. Interestingly, in pull-down experiments increasing concentrations of calcium drastically reduced the ability of these two proteins to interact, suggesting that NECAB2 binds to mGlu(5) receptor in a calcium-regulated manner. Immunoelectron microscopy detection of NECAB2 and mGlu(5) receptor in the rat hippocampal formation indicated that both proteins are codistributed in the same subcellular compartment of pyramidal cells. In addition, the NECAB2/mGlu(5) receptor interaction regulated mGlu(5b)-mediated activation of both inositol phosphate accumulation and the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway. Overall, these findings indicate that NECAB2 by its physical interaction with mGlu(5b) receptor modulates receptor function.

Mutations and polymorphisms in FSH receptor: functional implications in human reproduction.

Science.gov (United States)

Desai, Swapna S; Roy, Binita Sur; Mahale, Smita D

2013-12-01

FSH brings about its physiological actions by activating a specific receptor located on target cells. Normal functioning of the FSH receptor (FSHR) is crucial for follicular development and estradiol production in females and for the regulation of Sertoli cell function and spermatogenesis in males. In the last two decades, the number of inactivating and activating mutations, single nucleotide polymorphisms, and spliced variants of FSHR gene has been identified in selected infertile cases. Information on genotype-phenotype correlation and in vitro functional characterization of the mutants has helped in understanding the possible genetic cause for female infertility in affected individuals. The information is also being used to dissect various extracellular and intracellular events involved in hormone-receptor interaction by studying the differences in the properties of the mutant receptor when compared with WT receptor. Studies on polymorphisms in the FSHR gene have shown variability in clinical outcome among women treated with FSH. These observations are being explored to develop molecular markers to predict the optimum dose of FSH required for controlled ovarian hyperstimulation. Pharmacogenetics is an emerging field in this area that aims at designing individual treatment protocols for reproductive abnormalities based on FSHR gene polymorphisms. The present review discusses the current knowledge of various genetic alterations in FSHR and their impact on receptor function in the female reproductive system.

Functional properties of Virus-Encoded and Virus-Regulated 7TM Receptors

DEFF Research Database (Denmark)

Spiess, Katja; Rosenkilde, Mette Marie

2014-01-01

During co-evolution with their hosts, viruses have developed several survival strategies that involve exploitation of 7TM receptors. These include virus-encoded 7TM receptors and ligands and viral regulation of endogenous receptors. Many functional properties have been ascribed to virus-exploited...

Functional ET(A)-ET(B) Receptor Cross-talk in Basilar Artery In Situ From ET(B) Receptor Deficient Rats.

Science.gov (United States)

Yoon, SeongHun; Gariepy, Cheryl E; Yanagisawa, Masashi; Zuccarello, Mario; Rapoport, Robert M

2016-03-01

The role of endothelin (ET)(A)-ET(B) receptor cross-talk in limiting the ET(A) receptor antagonist inhibition of ET-1 constriction is revealed by the partial or complete dependency of the ET(A) receptor antagonist inhibition on functional removal of the ET(B) receptor. Although functional removal of the ET(B) receptor is generally accomplished with ET(B) receptor antagonist, a novel approach using rats containing a naturally occurring deletion mutation in the ET(B) receptor [rescued "spotting lethal" (sl) rats; ET(B)(sl/sl)] demonstrated increased ET(A) receptor antagonist inhibition of ET-1 constriction in vena cava. We investigated whether this deletion mutation was also sufficient to remove the ET(B) receptor dependency of the ET(A) receptor antagonist inhibition of ET-1 constriction in the basilar artery. Consistent with previous reports, ET-1 plasma levels were elevated in ET(B)(sl/sl) as compared with ET(B)(+/+) rats. ET(B) receptor antagonist failed to relax the ET-1 constricted basilar artery from ET(B)(+/+) and ET(B)(sl/sl) rats. Relaxation to combined ET(A) and ET(B) receptor antagonist was greater than relaxation to ET(A) receptor antagonist in the basilar artery from ET(B)(+/+) and, unexpectedly, ET(B)(sl/sl) rats. These findings confirm the presence of ET(A)-ET(B) receptor cross-talk in the basilar artery. We speculate that mutant ET(B) receptor expression produced by alternative splicing may be sufficient to allow cross-talk.

Genotype-Dependent Difference in 5-HT2C Receptor-Induced Hypolocomotion: Comparison with 5-HT2A Receptor Functional Activity

Directory of Open Access Journals (Sweden)

Darya V. Bazovkina

2015-01-01

Full Text Available In the present study behavioral effects of the 5-HT2C serotonin receptor were investigated in different mouse strains. The 5-HT2C receptor agonist MK-212 applied intraperitoneally induced significant dose-dependent reduction of distance traveled in the open field test in CBA/Lac mice. This effect was receptor-specific because it was inhibited by the 5-HT2C receptor antagonist RS102221. To study the role of genotype in 5-HT2C receptor-induced hypolocomotion, locomotor activity of seven inbred mouse strains was measured after MK-212 acute treatment. We found that the 5-HT2C receptor stimulation by MK-212 decreased distance traveled in the open field test in CBA/Lac, C57Bl/6, C3H/He, and ICR mice, whereas it failed to affect locomotor activity in DBA/2J, Asn, and Balb/c mice. We also compared the interstrain differences in functional response to 5-HT2C and 5-HT2A receptors activation measured by the quantification of receptor-mediated head-twitches. These experiments revealed significant positive correlation between 5-HT2C and 5-HT2A receptors functional responses for all investigated mouse strains. Moreover, we found that 5-HT2A receptor activation with DOI did not change locomotor activity in CBA/Lac mice. Taken together, our data indicate the implication of 5-HT2C receptors in regulation of locomotor activity and suggest the shared mechanism for functional responses mediated by 5-HT2C and 5-HT2A receptors.

Anxiety and beta-adrenergic receptor function in a normal population.

Science.gov (United States)

Kang, Eun-Ho; Yu, Bum-Hee

2005-06-01

Many studies have shown a close relationship between anxiety and beta-adrenergic receptor function in patients with anxiety disorders. This study examined the relationship between beta-adrenergic receptor function and anxiety levels in a normal population. Subjects for this study included 36 men and 44 women between the ages of 20 and 40 years whose Body Mass Index (BMI) was between 18 and 26. All of them were healthy subjects who had no previous history of medical or psychiatric illnesses. The authors measured the Spielberger State-Trait Anxiety Inventory (STAI), Beck Depression Inventory (BDI), and Chronotropic 25 Dose (CD25) of isoproterenol, previously developed to assess in vivo beta-adrenergic receptor sensitivity. We also examined correlations between log normalized CD25 and mood states. The mean of CD25 was 2.64+/-1.37 mug and the mean of CD25 in men was significantly higher (i.e., lower beta-adrenergic receptor sensitivity) than that of women (3.26+/-1.35 vs. 2.14+/-1.17 microg; t = 3.99, p anxiety (r = -0.344, p = 0.002), trait anxiety (r = -0.331, p = 0.003), and BDI (r = -0.283, p = 0.011). CD25 was positively correlated with BMI (r = 0.423, p anxiety, and BMI. The sensitivity of beta-adrenergic receptors increased as anxiety levels became higher in a normal population. Thus, the relationship between anxiety and beta-adrenergic receptor function in healthy subjects may be different from that of patients with anxiety disorders.

Dysregulation of the HPA axis as a core pathophysiology mediating co-morbid depression in neurodegenerative diseases

Directory of Open Access Journals (Sweden)

Xin eDu

2015-03-01

Full Text Available There is increasing evidence of prodromal manifestation of neuropsychiatric symptoms in a variety of neurodegenerative diseases such as Parkinson’s disease and Huntington’s disease. These affective symptoms may be observed many years before the core diagnostic symptoms of the neurological condition. It is becoming more apparent that depression is a significant modifying factor of the trajectory of disease progression, and even treatment outcomes. It is therefore crucial that we understand the potential pathophysiologies related to the primary condition, which could contribute to the development of depression. The hypothalamic-pituitary-adrenal (HPA axis is a key neuroendocrine signaling system involved in physiological homeostasis and stress response. Disturbances of this system lead to severe hormonal imbalances, and the majority of such patients also present with behavioural deficits and/or mood disorders. Dysregulation of the HPA axis is also strongly implicated in the pathology of major depressive disorder. Consistent with this, anti-depressant drugs such as the selective serotonin reuptake inhibitors (SSRI have been shown to alter HPA axis activity. In this review, we will summarize the current state of knowledge regarding HPA axis pathology in Alzheimer’s, Parkinson’s and Huntington’s diseases, differentiating between prodromal and later stages of disease progression where possible. Both clinical and preclinical evidence will be examined, but we highlight animal model studies as being particularly useful for uncovering novel mechanisms of pathology related to co-morbid mood disorders. Finally, we purpose utilizing the pre-clinical evidence to better inform prospective, intervention studies.

Graft-derived anti-HPA-2b production after allogeneic bone-marrow transplantation

DEFF Research Database (Denmark)

Taaning, E; Jacobsen, N; Morling, N

1994-01-01

We report on a male who received a bone-marrow allograft from his HLA identical sister for acute myelogenous leukaemia. After transplantation, the patient suffered from refractoriness to the transfusions of HLA-matched platelets and a strong platelet-specific antibody, anti-HPA-2b, of IgG1 subcla...

Bisphenol A affects androgen receptor function via multiple mechanisms.

Science.gov (United States)

Teng, Christina; Goodwin, Bonnie; Shockley, Keith; Xia, Menghang; Huang, Ruili; Norris, John; Merrick, B Alex; Jetten, Anton M; Austin, Christopher P; Tice, Raymond R

2013-05-25

Bisphenol A (BPA), is a well-known endocrine disruptor compound (EDC) that affects the normal development and function of the female and male reproductive system, however the mechanisms of action remain unclear. To investigate the molecular mechanisms of how BPA may affect ten different nuclear receptors, stable cell lines containing individual nuclear receptor ligand binding domain (LBD)-linked to the β-Gal reporter were examined by a quantitative high throughput screening (qHTS) format in the Tox21 Screening Program of the NIH. The results showed that two receptors, estrogen receptor alpha (ERα) and androgen receptor (AR), are affected by BPA in opposite direction. To confirm the observed effects of BPA on ERα and AR, we performed transient transfection experiments with full-length receptors and their corresponding response elements linked to luciferase reporters. We also included in this study two BPA analogs, bisphenol AF (BPAF) and bisphenol S (BPS). As seen in African green monkey kidney CV1 cells, the present study confirmed that BPA and BPAF act as ERα agonists (half maximal effective concentration EC50 of 10-100 nM) and as AR antagonists (half maximal inhibitory concentration IC50 of 1-2 μM). Both BPA and BPAF antagonized AR function via competitive inhibition of the action of synthetic androgen R1881. BPS with lower estrogenic activity (EC50 of 2.2 μM), did not compete with R1881 for AR binding, when tested at 30 μM. Finally, the effects of BPA were also evaluated in a nuclear translocation assays using EGPF-tagged receptors. Similar to 17β-estradiol (E2) which was used as control, BPA was able to enhance ERα nuclear foci formation but at a 100-fold higher concentration. Although BPA was able to bind AR, the nuclear translocation was reduced. Furthermore, BPA was unable to induce functional foci in the nuclei and is consistent with the transient transfection study that BPA is unable to activate AR. Published by Elsevier Ireland Ltd.

M1 muscarinic receptor facilitates cognitive function by interplay with AMPA receptor GluA1 subunit.

Science.gov (United States)

Zhao, Lan-Xue; Ge, Yan-Hui; Xiong, Cai-Hong; Tang, Ling; Yan, Ying-Hui; Law, Ping-Yee; Qiu, Yu; Chen, Hong-Zhuan

2018-03-06

M1 muscarinic acetylcholine receptors (M1 mAChRs) are the most abundant muscarinic receptors in the hippocampus and have been shown to have procognitive effects. AMPA receptors (AMPARs), an important subtype of ionotropic glutamate receptors, are key components in neurocognitive networks. However, the role of AMPARs in procognitive effects of M1 mAChRs and how M1 mAChRs affect the function of AMPARs remain poorly understood. Here, we found that basal expression of GluA1, a subunit of AMPARs, and its phosphorylation at Ser845 were maintained by M1 mAChR activity. Activation of M1 mAChRs promoted membrane insertion of GluA1, especially to postsynaptic densities. Impairment of hippocampus-dependent learning and memory by antagonism of M1 mAChRs paralleled the reduction of GluA1 expression, and improvement of learning and memory by activation of M1 mAChRs was accompanied by the synaptic insertion of GluA1 and its increased phosphorylation at Ser845. Furthermore, abrogation of phosphorylation of Ser845 residue of GluA1 ablated M1 mAChR-mediated improvement of learning and memory. Taken together, these results show a functional correlation of M1 mAChRs and GluA1 and the essential role of GluA1 in M1 mAChR-mediated cognitive improvement.-Zhao, L.-X., Ge, Y.-H., Xiong, C.-H., Tang, L., Yan, Y.-H., Law, P.-Y., Qiu, Y., Chen, H.-Z. M1 muscarinic receptor facilitates cognitive function by interplay with AMPA receptor GluA1 subunit.

Comparative Genomics Identifies a Novel Conserved Protein, HpaT, in Proteobacterial Type III Secretion Systems that Do Not Possess the Putative Translocon Protein HrpF

Directory of Open Access Journals (Sweden)

Céline Pesce

2017-06-01

Full Text Available Xanthomonas translucens is the causal agent of bacterial leaf streak, the most common bacterial disease of wheat and barley. To cause disease, most xanthomonads depend on a highly conserved type III secretion system, which translocates type III effectors into host plant cells. Mutagenesis of the conserved type III secretion gene hrcT confirmed that the X. translucens type III secretion system is required to cause disease on the host plant barley and to trigger a non-host hypersensitive response (HR in pepper leaves. Type III effectors are delivered to the host cell by a surface appendage, the Hrp pilus, and a translocon protein complex that inserts into the plant cell plasma membrane. Homologs of the Xanthomonas HrpF protein, including PopF from Ralstonia solanacearum and NolX from rhizobia, are thought to act as a translocon protein. Comparative genomics revealed that X. translucens strains harbor a noncanonical hrp gene cluster, which rather shares features with type III secretion systems from Ralstonia solanacearum, Paraburkholderia andropogonis, Collimonas fungivorans, and Uliginosibacterium gangwonense than other Xanthomonas spp. Surprisingly, none of these bacteria, except R. solanacearum, encode a homolog of the HrpF translocon. Here, we aimed at identifying a candidate translocon from X. translucens. Notably, genomes from strains that lacked hrpF/popF/nolX instead encode another gene, called hpaT, adjacent to and co-regulated with the type III secretion system gene cluster. An insertional mutant in the X. translucens hpaT gene, which is the first gene of a two-gene operon, hpaT-hpaH, was non-pathogenic on barley and did not cause the HR or programmed cell death in non-host pepper similar to the hrcT mutant. The hpaT mutant phenotypes were partially complemented by either hpaT or the downstream gene, hpaH, which has been described as a facilitator of translocation in Xanthomonas oryzae. Interestingly, the hpaT mutant was also complemented

硫糖铝在体外对抗幽门螺杆菌HpaA IgY的保护作用评价%Evaluation on Protective Effects of Sucralfate on Anti-H.pylori HpaA IgY in Vitro

Institute of Scientific and Technical Information of China (English)

邓西川; 黄伟; 戴维; 胡晓莉; 沈旭东; 杨致邦

2011-01-01

目的 评价硫糖铝对HpaAIgY的保护作用,为制备IgY口服制剂奠定基础.方法 大量诱导工程菌DH5α-HpaA-pQE30,制备纯化的重组蛋白HpaA.以HpaA为抗原接种洛曼母鸡,制备纯化的IgY.在不同pH值,舍不同浓度胃蛋白酶的HpaAIgY液中加入不同浓度的硫糖铝;将IgY液反复冻融;以ELISA法测定HpaAIgY的剩余抗体活性(AR/AC).结果 在pH1.5条件下,60%硫糖铝可使IgY抗体剩余活性维持65.8%;在pH 2.0条件下,舍30%硫糖铝的IgY可使抗体活性维持85.4%,含50%硫糖铝的IgY可完全维持抗体活性.在pH 3.0条件下,含30%硫糖铝的IgY可使抗体活性维持87.3%,而含40%以上硫糖铝的IgY几乎可完全维持抗体活性.在胃蛋白酶浓度0.02mg/mL条件下,当含10%、30%、50%硫糖铝IgY的剩余活性,在pH值2.0时,分别为62.8%、71.6%、82.5%;在pH值3.0时,分别为75.6%、87.4%、94.5%;反复冻融后,含10%硫糖铝的IgY可使抗体活性提高到70.6%,含30%硫糖铝可使IgY的抗体活性提高到82.7%,50%硫糖铝可提高到89.3%.结论 30%以上的硫糖铝可增强VacAIgY对低pH和胃蛋白酶的耐受能力,抗冻融能力,是较理想的IgY保护剂.

Angiotensin type 1 receptors in the subfornical organ mediate the drinking and hypothalamic-pituitary-adrenal response to systemic isoproterenol.

Science.gov (United States)

Krause, Eric G; Melhorn, Susan J; Davis, Jon F; Scott, Karen A; Ma, Li Y; de Kloet, Annette D; Benoit, Stephen C; Woods, Stephen C; Sakai, Randall R

2008-12-01

Circulating angiotensin II (ANGII) elicits water intake and activates the hypothalamic-pituitary-adrenal (HPA) axis by stimulating angiotensin type 1 receptors (AT1Rs) within circumventricular organs. The subfornical organ (SFO) and the organum vasculosum of the lamina terminalis (OVLT) are circumventricular organs that express AT1Rs that bind blood-borne ANGII and stimulate integrative and effector regions of the brain. The goal of these studies was to determine the contribution of AT1Rs within the SFO and OVLT to the water intake and HPA response to increased circulating ANGII. Antisense oligonucleotides directed against the AT1R [AT1R antisense (AT1R AS)] were administered into the OVLT or SFO. Quantitative receptor autoradiography confirmed that AT1R AS decreased ANGII binding in the SFO and OVLT compared with the scrambled sequence control but did not affect AT1R binding in other nuclei. Subsequently, water intake, ACTH, and corticosterone (CORT) were assessed after administration of isoproterenol, a beta-adrenergic agonist that decreases blood pressure and elevates circulating ANGII. Delivery of AT1R AS into the SFO attenuated water intake, ACTH, and CORT after isoproterenol, whereas similar treatment in the OVLT had no effect. To determine the specificity of this blunted drinking and HPA response, the same parameters were measured after treatment with hypertonic saline, a stimulus that induces drinking independently of ANGII. Delivery of AT1R AS into the SFO or OVLT had no effect on water intake, ACTH, or CORT after hypertonic saline. The results imply that AT1R within the SFO mediate drinking and HPA responses to stimuli that increase circulating ANGII.

DMPD: Shaping of monocyte and macrophage function by adenosine receptors. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 17056121 Shaping of monocyte and macrophage function by adenosine receptors. Hasko ...tml) (.csml) Show Shaping of monocyte and macrophage function by adenosine receptors. PubmedID 17056121 Titl...e Shaping of monocyte and macrophage function by adenosine receptors. Authors Has

Burnout Is Associated with Reduced Parasympathetic Activity and Reduced HPA Axis Responsiveness, Predominantly in Males

Directory of Open Access Journals (Sweden)

Wieke de Vente

2015-01-01

Full Text Available There is mounting evidence that burnout is a risk factor for cardiovascular disease (CVD. Stress-related dysregulation of the sympathetic and parasympathetic system and the hypothalamic pituitary adrenal (HPA axis may explain the enhanced risk for CVD. To test this hypothesis, 55 patients (34 males and 21 females with burnout on sickness absence and 40 healthy participants (16 males and 24 females were exposed to a psychosocial stressor consisting of mental arithmetic and public speech. Physiological variables (i.e., blood pressure, heart rate, cardiac output, vascular resistance, cortisol, and alpha-amylase were measured. Basal levels, reactivity, and recovery were compared between groups. In male patients, baseline systolic blood pressure was higher, whereas basal alpha-amylase and cortisol reactivity were lower than in healthy males. In female patients, a tendency for lower basal cortisol was found as compared to healthy females. Furthermore, reduced basal heart rate variability and a trend for elevated basal cardiac output were observed in both male and female patients. Burnout is characterised by dysregulation of the sympathetic and parasympathetic system and the HPA axis, which was more pronounced in males than in females. This study further supports burnout as being a risk factor for CVD through dysregulation of the sympathetic and parasympathetic system and the HPA axis.

Melatonin membrane receptors in peripheral tissues: Distribution and functions

Science.gov (United States)

Slominski, Radomir M.; Reiter, Russel J.; Schlabritz-Loutsevitch, Natalia; Ostrom, Rennolds S.; Slominski, Andrzej T.

2012-01-01

Many of melatonin’s actions are mediated through interaction with the G-protein coupled membrane bound melatonin receptors type 1 and type 2 (MT1 and MT2, respectively) or, indirectly with nuclear orphan receptors from the RORα/RZR family. Melatonin also binds to the quinone reductase II enzyme, previously defined the MT3 receptor. Melatonin receptors are widely distributed in the body; herein we summarize their expression and actions in non-neural tissues. Several controversies still exist regarding, for example, whether melatonin binds the RORα/RZR family. Studies of the peripheral distribution of melatonin receptors are important since they are attractive targets for immunomodulation, regulation of endocrine, reproductive and cardiovascular functions, modulation of skin pigmentation, hair growth, cancerogenesis, and aging. Melatonin receptor agonists and antagonists have an exciting future since they could define multiple mechanisms by which melatonin modulates the complexity of such a wide variety of physiological and pathological processes. PMID:22245784

Evidence against a critical role of CB1 receptors in adaptation of the hypothalamic-pituitary-adrenal axis and other consequences of daily repeated stress.

Science.gov (United States)

Rabasa, Cristina; Pastor-Ciurana, Jordi; Delgado-Morales, Raúl; Gómez-Román, Almudena; Carrasco, Javier; Gagliano, Humberto; García-Gutiérrez, María S; Manzanares, Jorge; Armario, Antonio

2015-08-01

There is evidence that endogenous cannabinoids (eCBs) play a role in the control of the hypothalamic-pituitary-adrenal (HPA) axis, although they appear to have dual, stimulatory and inhibitory, effects. Recent data in rats suggest that eCBs, acting through CB1 receptors (CB1R), may be involved in adaptation of the HPA axis to daily repeated stress. In the present study we analyze this issue in male mice and rats. Using a knock-out mice for the CB1 receptor (CB1-/-) we showed that mutant mice presented similar adrenocorticotropic hormone (ACTH) response to the first IMO as wild-type mice. Daily repeated exposure to 1h of immobilization reduced the ACTH response to the stressor, regardless of the genotype, demonstrating that adaptation occurred to the same extent in absence of CB1R. Prototypical changes observed after repeated stress such as enhanced corticotropin releasing factor (CRH) gene expression in the paraventricular nucleus of the hypothalamus, impaired body weight gain and reduced thymus weight were similarly observed in both genotypes. The lack of effect of CB1R in the expression of HPA adaptation to another similar stressor (restraint) was confirmed in wild-type CD1 mice by the lack of effect of the CB1R antagonist AM251 just before the last exposure to stress. Finally, the latter drug did not blunt the HPA, glucose and behavioral adaptation to daily repeated forced swim in rats. Thus, the present results indicate that CB1R is not critical for overall effects of daily repeated stress or proper adaptation of the HPA axis in mice and rats. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

Curcumin reverses the effects of chronic stress on behavior, the HPA axis, BDNF expression and phosphorylation of CREB.

Science.gov (United States)

Xu, Ying; Ku, Baoshan; Tie, Lu; Yao, Haiyan; Jiang, Wengao; Ma, Xing; Li, Xuejun

2006-11-29

Curcuma longa is a major constituent of the traditional Chinese medicine Xiaoyao-san, which has been used to effectively manage stress and depression-related disorders in China. Curcumin is the active component of curcuma longa, and its antidepressant effects were described in our prior studies in mouse models of behavioral despair. We hypothesized that curcumin may also alleviate stress-induced depressive-like behaviors and hypothalamic-pituitary-adrenal (HPA) axis dysfunction. Thus in present study we assessed whether curcumin treatment (2.5, 5 and 10 mg/kg, p.o.) affects behavior in a chronic unpredictable stress model of depression in rats and examined what its molecular targets may be. We found that subjecting animals to the chronic stress protocol for 20days resulted in performance deficits in the shuttle-box task and several physiological effects, such as an abnormal adrenal gland weight to body weight (AG/B) ratio and increased thickness of the adrenal cortex as well as elevated serum corticosterone levels and reduced glucocorticoid receptor (GR) mRNA expression. These changes were reversed by chronic curcumin administration (5 or 10 mg/kg, p.o.). In addition, we also found that the chronic stress procedure induced a down-regulation of brain-derived neurotrophic factor (BDNF) protein levels and reduced the ratio of phosphorylated cAMP response element-binding protein (pCREB) to CREB levels (pCREB/CREB) in the hippocampus and frontal cortex of stressed rats. Furthermore, these stress-induced decreases in BDNF and pCREB/CREB were also blocked by chronic curcumin administration (5 or 10 mg/kg, p.o.). These results provide compelling evidence that the behavioral effects of curcumin in chronically stressed animals, and by extension humans, may be related to their modulating effects on the HPA axis and neurotrophin factor expressions.

Functional role of cannabinoid receptors in urinary bladder

Directory of Open Access Journals (Sweden)

Pradeep Tyagi

2010-01-01

Full Text Available Cannabinoids, the active components of Cannabis sativa (marijuana, and their derivatives produce a wide spectrum of central and peripheral effects, some of which may have clinical applications. The discovery of specific cannabinoid receptors and a family of endogenous ligands of those receptors has attracted much attention to the general cannabinoid pharmacology. In recent years, studies on the functional role of cannabinoid receptors in bladder have been motivated by the therapeutic effects of cannabinoids on voiding dysfunction in multiple sclerosis patients. In this review, we shall summarize the literature on the expression of cannabinoid receptors in urinary bladder and the peripheral influence of locally and systemically administered cannabinoids in the bladder. The ongoing search for cannabinoid-based therapeutic strategies devoid of psychotropic effects can be complemented with local delivery into bladder by the intravesical route. A greater understanding of the role of the peripheral CB 1 and CB 2 receptor system in lower urinary tract is necessary to allow the development of new treatment for pelvic disorders.

Chronic stress and pituitary-adrenal function in female pigs

NARCIS (Netherlands)

Janssens, C.J.J.G.

1994-01-01

Introduction

The main purpose of the studies described in this thesis was to gain more insight in the regulation of the hypothalamic-pituitary-adrenocorticaI (HPA) system and the mechanisms underlying adaptation to chronic stress in female pigs. The function of the HPA axis, which

Scavenger Receptor Structure and Function in Health and Disease

Directory of Open Access Journals (Sweden)

Izma Abdul Zani

2015-05-01

Full Text Available Scavenger receptors (SRs are a ‘superfamily’ of membrane-bound receptors that were initially thought to bind and internalize modified low-density lipoprotein (LDL, though it is currently known to bind to a variety of ligands including endogenous proteins and pathogens. New family of SRs and their properties have been identified in recent years, and have now been classified into 10 eukaryote families, defined as Classes A-J. These receptors are classified according to their sequences, although in each class they are further classified based in the variations of the sequence. Their ability to bind a range of ligands is reflected on the biological functions such as clearance of modified lipoproteins and pathogens. SR members regulate pathophysiological states including atherosclerosis, pathogen infections, immune surveillance, and cancer. Here, we review our current understanding of SR structure and function implicated in health and disease.

Conformational transitions and interactions underlying the function of membrane embedded receptor protein kinases.

Science.gov (United States)

Bocharov, Eduard V; Sharonov, Georgy V; Bocharova, Olga V; Pavlov, Konstantin V

2017-09-01

Among membrane receptors, the single-span receptor protein kinases occupy a broad but specific functional niche determined by distinctive features of the underlying transmembrane signaling mechanisms that are briefly overviewed on the basis of some of the most representative examples, followed by a more detailed discussion of several hierarchical levels of organization and interactions involved. All these levels, including single-molecule interactions (e.g., dimerization, liganding, chemical modifications), local processes (e.g. lipid membrane perturbations, cytoskeletal interactions), and larger scale phenomena (e.g., effects of membrane surface shape or electrochemical potential gradients) appear to be closely integrated to achieve the observed diversity of the receptor functioning. Different species of receptor protein kinases meet their specific functional demands through different structural features defining their responses to stimulation, but certain common patterns exist. Signaling by receptor protein kinases is typically associated with the receptor dimerization and clustering, ligand-induced rearrangements of receptor domains through allosteric conformational transitions with involvement of lipids, release of the sequestered lipids, restriction of receptor diffusion, cytoskeleton and membrane shape remodeling. Understanding of complexity and continuity of the signaling processes can help identifying currently neglected opportunities for influencing the receptor signaling with potential therapeutic implications. This article is part of a Special Issue entitled: Interactions between membrane receptors in cellular membranes edited by Kalina Hristova. Copyright © 2017 Elsevier B.V. All rights reserved.

Functional polymorphisms in the P2X7 receptor gene are associated with osteoporosis

DEFF Research Database (Denmark)

Husted, L B; Harsløf, T; Stenkjær, L

2013-01-01

variant allele, which has been associated with increased receptor function in monocytes, was associated with increased total hip BMD in women. With the exception of His155Tyr for which we found conflicting results in men and women, our results are consistent with the phenotype of the knockout mouse......UNLABELLED: The P2X(7) receptor is an ATP-gated cation channel. We investigated the effect of both loss-of-function and gain-of-function polymorphisms in the P2X(7) receptor gene on BMD and risk of vertebral fractures and found that five polymorphisms and haplotypes containing three...... of these polymorphisms were associated with BMD and fracture risk. INTRODUCTION: The P2X(7) receptor is an ATP-gated cation channel. P2X(7) receptor knockout mice have reduced total bone mineral content, and because several functional polymorphisms have been identified in the human P2X(7) receptor gene, we wanted...

Multivalent Fcγ-receptor engagement by a hexameric Fc-fusion protein triggers Fcγ-receptor internalisation and modulation of Fcγ-receptor functions.

Science.gov (United States)

Qureshi, O S; Rowley, T F; Junker, F; Peters, S J; Crilly, S; Compson, J; Eddleston, A; Björkelund, H; Greenslade, K; Parkinson, M; Davies, N L; Griffin, R; Pither, T L; Cain, K; Christodoulou, L; Staelens, L; Ward, E; Tibbitts, J; Kiessling, A; Smith, B; Brennan, F R; Malmqvist, M; Fallah-Arani, F; Humphreys, D P

2017-12-06

Engagement of Fcγ-receptors triggers a range of downstream signalling events resulting in a diverse array of immune functions. As a result, blockade of Fc-mediated function is an important strategy for the control of several autoimmune and inflammatory conditions. We have generated a hexameric-Fc fusion protein (hexameric-Fc) and tested the consequences of multi-valent Fcγ-receptor engagement in in vitro and in vivo systems. In vitro engagement of hexameric-Fc with FcγRs showed complex binding interactions that altered with receptor density and triggered the internalisation and degradation of Fcγ-receptors. This caused a disruption of Fc-binding and phagocytosis. In vivo, in a mouse ITP model we observed a short half-life of hexameric-Fc but were nevertheless able to observe inhibition of platelet phagocytosis several days after hexameric-Fc dosing. In cynomolgus monkeys, we again observed a short half-life, but were able to demonstrate effective FcγR blockade. These findings demonstrate the ability of multi-valent Fc-based therapeutics to interfere with FcγR function and a potential mechanism through which they could have a sustained effect; the internalisation and degradation of FcγRs.

Functional Validation of Heteromeric Kainate Receptor Models.

Science.gov (United States)

Paramo, Teresa; Brown, Patricia M G E; Musgaard, Maria; Bowie, Derek; Biggin, Philip C

2017-11-21

Kainate receptors require the presence of external ions for gating. Most work thus far has been performed on homomeric GluK2 but, in vivo, kainate receptors are likely heterotetramers. Agonists bind to the ligand-binding domain (LBD) which is arranged as a dimer of dimers as exemplified in homomeric structures, but no high-resolution structure currently exists of heteromeric kainate receptors. In a full-length heterotetramer, the LBDs could potentially be arranged either as a GluK2 homomer alongside a GluK5 homomer or as two GluK2/K5 heterodimers. We have constructed models of the LBD dimers based on the GluK2 LBD crystal structures and investigated their stability with molecular dynamics simulations. We have then used the models to make predictions about the functional behavior of the full-length GluK2/K5 receptor, which we confirmed via electrophysiological recordings. A key prediction and observation is that lithium ions bind to the dimer interface of GluK2/K5 heteromers and slow their desensitization. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Mood states, sympathetic activity, and in vivo beta-adrenergic receptor function in a normal population.

Science.gov (United States)

Yu, Bum-Hee; Kang, Eun-Ho; Ziegler, Michael G; Mills, Paul J; Dimsdale, Joel E

2008-01-01

The purpose of this study was to examine the relationship between mood states and beta-adrenergic receptor function in a normal population. We also examined if sympathetic nervous system activity is related to mood states or beta-adrenergic receptor function. Sixty-two participants aged 25-50 years were enrolled in this study. Mood states were assessed using the Profile of Mood States (POMS). Beta-adrenergic receptor function was determined using the chronotropic 25 dose isoproterenol infusion test. Level of sympathetic nervous system activity was estimated from 24-hr urine norepinephrine excretion. Higher tension-anxiety, depression-dejection, and anger-hostility were related to decreased beta-adrenergic receptor sensitivity (i.e., higher chronotropic 25 dose values), but tension-anxiety was the only remaining independent predictor of beta-adrenergic receptor function after controlling for age, gender, ethnicity, and body mass index (BMI). Urinary norepinephrine excretion was unrelated to either mood states or beta-adrenergic receptor function. These findings replicate previous reports that anxiety is related to decreased (i.e., desensitized) beta-adrenergic receptor sensitivity, even after controlling for age, gender, ethnicity, and body mass index.

Function of the cytoplasmic tail of human calcitonin receptor-like receptor in complex with receptor activity-modifying protein 2

Energy Technology Data Exchange (ETDEWEB)

Kuwasako, Kenji, E-mail: kuwasako@fc.miyazaki-u.ac.jp [Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692 (Japan); Kitamura, Kazuo; Nagata, Sayaka; Hikosaka, Tomomi [Division of Circulation and Body Fluid Regulation, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692 (Japan); Kato, Johji [Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692 (Japan)

2010-02-12

Receptor activity-modifying protein 2 (RAMP2) enables calcitonin receptor-like receptor (CRLR) to form an adrenomedullin (AM)-specific receptor. Here we investigated the function of the cytoplasmic C-terminal tail (C-tail) of human (h)CRLR by co-transfecting its C-terminal mutants into HEK-293 cells stably expressing hRAMP2. Deleting the C-tail from CRLR disrupted AM-evoked cAMP production or receptor internalization, but did not affect [{sup 125}I]AM binding. We found that CRLR residues 428-439 are required for AM-evoked cAMP production, though deleting this region had little effect on receptor internalization. Moreover, pretreatment with pertussis toxin (100 ng/mL) led to significant increases in AM-induced cAMP production via wild-type CRLR/RAMP2 complexes. This effect was canceled by deleting CRLR residues 454-457, suggesting Gi couples to this region. Flow cytometric analysis revealed that CRLR truncation mutants lacking residues in the Ser/Thr-rich region extending from Ser{sup 449} to Ser{sup 467} were unable to undergo AM-induced receptor internalization and, in contrast to the effect on wild-type CRLR, overexpression of GPCR kinases-2, -3 and -4 failed to promote internalization of CRLR mutants lacking residues 449-467. Thus, the hCRLR C-tail is crucial for AM-evoked cAMP production and internalization of the CRLR/RAMP2, while the receptor internalization is dependent on the aforementioned GPCR kinases, but not Gs coupling.

Functional specificity of sex pheromone receptors in the cotton bollworm Helicoverpa armigera.

Directory of Open Access Journals (Sweden)

Yang Liu

Full Text Available Male moths can accurately perceive the sex pheromone emitted from conspecific females by their highly accurate and specific olfactory sensory system. Pheromone receptors are of special importance in moth pheromone reception because of their central role in chemosensory signal transduction processes that occur in olfactory receptor neurons in the male antennae. There are a number of pheromone receptor genes have been cloned, however, only a few have been functionally characterized. Here we cloned six full-length pheromone receptor genes from Helicoverpa armigera male antennae. Real-time PCR showing all genes exhibited male-biased expression in adult antennae. Functional analyses of the six pheromone receptor genes were then conducted in the heterologous expression system of Xenopus oocytes. HarmOR13 was found to be a specific receptor for the major sex pheromone component Z11-16:Ald. HarmOR6 was equally tuned to both of Z9-16: Ald and Z9-14: Ald. HarmOR16 was sensitively tuned to Z11-16: OH. HarmOR11, HarmOR14 and HarmOR15 failed to respond to the tested candidate pheromone compounds. Our experiments elucidated the functions of some pheromone receptor genes of H. armigera. These advances may provide remarkable evidence for intraspecific mating choice and speciation extension in moths at molecular level.

Class I Cytokine Receptors: Structure and function in the Membrane

DEFF Research Database (Denmark)

Bugge, Katrine Østergaard

bilayer via structural characterizations of TMD representatives. To enable structural studies of these domains, an organic-extraction based strategy for efficient production of isotope-labeled TMDs with or without short intrinsically disordered regions was developed. This strategy successfully provided...... of these challenging domains. Supplemented by a review of the current collection of TMD structures from single-pass transmembrane receptors, the thesis as a whole provides important insights on the structure and function in the membrane as well as highlight the open questions to be addressed in the years to come.......Class I cytokine receptors are involved in important biological functions of both physiological and pathological nature in mammals. However, the molecular details of the cross-membrane signal transduction through these receptors remain obscure. One of the major reasons for this is the lack...

AmTAR2: Functional characterization of a honeybee tyramine receptor stimulating adenylyl cyclase activity.

Science.gov (United States)

Reim, Tina; Balfanz, Sabine; Baumann, Arnd; Blenau, Wolfgang; Thamm, Markus; Scheiner, Ricarda

2017-01-01

The biogenic monoamines norepinephrine and epinephrine regulate important physiological functions in vertebrates. Insects such as honeybees do not synthesize these neuroactive substances. Instead, they employ octopamine and tyramine for comparable physiological functions. These biogenic amines activate specific guanine nucleotide-binding (G) protein-coupled receptors (GPCRs). Based on pharmacological data obtained on heterologously expressed receptors, α- and β-adrenergic-like octopamine receptors are better activated by octopamine than by tyramine. Conversely, GPCRs forming the type 1 tyramine receptor clade (synonymous to octopamine/tyramine receptors) are better activated by tyramine than by octopamine. More recently, receptors were characterized which are almost exclusively activated by tyramine, thus forming an independent type 2 tyramine receptor clade. Functionally, type 1 tyramine receptors inhibit adenylyl cyclase activity, leading to a decrease in intracellular cAMP concentration ([cAMP] i ). Type 2 tyramine receptors can mediate Ca 2+ signals or both Ca 2+ signals and effects on [cAMP] i . We here provide evidence that the honeybee tyramine receptor 2 (AmTAR2), when heterologously expressed in flpTM cells, exclusively causes an increase in [cAMP] i . The receptor displays a pronounced preference for tyramine over octopamine. Its activity can be blocked by a series of established antagonists, of which mianserin and yohimbine are most efficient. The functional characterization of two tyramine receptors from the honeybee, AmTAR1 (previously named AmTYR1) and AmTAR2, which respond to tyramine by changing cAMP levels in opposite direction, is an important step towards understanding the actions of tyramine in honeybee behavior and physiology, particularly in comparison to the effects of octopamine. Copyright © 2016 Elsevier Ltd. All rights reserved.

Activation of the Hypothalamic-Pituitary-Adrenal (HPA) Axis Following Extended Exposure to Atrazine (ATR)

Science.gov (United States)

While it is known that adrenal steroids impact reproduction and a variety of other physiological and behavioral fimctions, disruption of the HPA-axis is not typically considered in toxicological studies. Here we characterize changes in basal corticosterone (CORT) and progesterone...

METHODS FOR RECOMBINANT EXPRESSION AND FUNCTIONAL CHARACTERIZATION OF HUMAN CANNABINOID RECEPTOR CB2

Directory of Open Access Journals (Sweden)

Alexei A. Yeliseev

2013-03-01

Full Text Available Cannabinoid receptor CB2 is a seven transmembrane-domain integral membrane protein that belongs to a large superfamily of G protein-coupled receptors (GPCR. CB2 is a part of the endocannabinoid system that plays vital role in regulation of immune response, inflammation, pain sensitivity, obesity and other physiological responses. Information about the structure and mechanisms of functioning of this receptor in cell membranes is essential for the rational development of specific pharmaceuticals. Here we review the methodology for recombinant expression, purification, stabilization and biochemical characterization of CB2 suitable for preparation of multi-milligram quantities of functionally active receptor. The biotechnological protocols include expression of the recombinant CB2 in E. coli cells as a fusion with the maltose binding protein, stabilization with a high affinity ligand and a derivative of cholesterol in detergent micelles, efficient purification by tandem affinity chromatography, and reconstitution of the receptor into lipid bilayers. The purified recombinant CB2 receptor is amenable to functional and structural studies including nuclear magnetic resonance spectroscopy and a wide range of biochemical and biophysical techniques.

DMPD: G-protein-coupled receptor expression, function, and signaling in macrophages. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 17456803 G-protein-coupled receptor expression, function, and signaling in macropha...2007 Apr 24. (.png) (.svg) (.html) (.csml) Show G-protein-coupled receptor expression, function, and signali...ng in macrophages. PubmedID 17456803 Title G-protein-coupled receptor expression, function

The First Fifteen Years of Steroid Receptor Research in Zebrafish; Characterization and Functional Analysis of the Receptors

Directory of Open Access Journals (Sweden)

Marcel J. M. Schaaf

2017-07-01

Full Text Available Steroid hormones regulate a wide range of processes in our body, and their effects are mediated by steroid receptors. In addition to their physiological role, these receptors mediate the effects of endocrine disrupting chemicals (EDCs and are widely used targets for dugs involved in the treatment of numerous diseases, ranging from cancer to inflammatory disorders. Over the last fifteen years, the zebrafish has increasingly been used as an animal model in steroid receptor research. Orthologues of all human steroid receptor genes appear to be present in zebrafish. All zebrafish steroid receptors have been characterized in detail, and their expression patterns have been analyzed. Functional studies have been performed using morpholino knockdown of receptor expression and zebrafish lines carrying mutations in one of their steroid receptor genes. To investigate the activity of the receptors in vivo, specific zebrafish reporter lines have been developed, and transcriptomic studies have been carried out to identify biomarkers for steroid receptor action. In this review, an overview of research on steroid receptors in zebrafish is presented, and it is concluded that further exploitation of the possibilities of the zebrafish model system will contribute significantly to the advancement of steroid receptor research in the next decade.

Taking Stress Response out of the Box: Stability, Discontinuity, and Temperament Effects on HPA and SNS across Social Stressors in Mother-Infant Dyads

Science.gov (United States)

Laurent, Heidemarie K.; Ablow, Jennifer C.; Measelle, Jeffrey

2012-01-01

This study investigated continuity and stability of hypothalamic-pituitary-adrenal (HPA) and sympathetic nervous system (SNS) response measures in mother-infant dyads across 2 different types of social stress sessions. Synchrony of response trajectories across systems (SNS-HPA coordination) and partners (mother-infant attunement) was addressed, as…

Nature and regulation of the insulin receptor: structure and function

International Nuclear Information System (INIS)

Czech, M.P.

1985-01-01

Native, cell-surface insulin receptor consists of two glycoprotein subunit types with apparent masses of about 125,000 daltons (alpha subunit) and 90,000 daltons (beta subunit). The alpha and beta insulin-receptor subunits seem to have distinct functions such that alpha appears to bind hormone whereas beta appears to possess intrinsic tyrosine kinase activity. In detergent extracts, insulin activates receptor autophosphorylation of tyrosine residues on its beta subunit, whereas in the presence of reductant, the alpha subunit is also phosphorylated. In intact cells, insulin activates serine/threonine phosphorylation of insulin receptor beta subunit as well as tyrosine phosphorylation. The biological role of the receptor-associated tyrosine kinase is not known. The insulin receptor kinase is regulated by beta-adrenergic agonists and other agents that elevate cAMP in adipocytes, presumably via the cAMP-dependent protein kinase. Such agents decrease receptor affinity for insulin and partially uncouple receptor tyrosine kinase activity from activation by insulin. These effects appear to contribute to the biological antagonism between insulin and beta-agonists. These data suggest the hypothesis that a complex network of tyrosine and serine/threonine phosphorylations on the insulin receptor modulate its binding and kinase activities in an antagonistic manner

Evidence for Stress-like Alterations in the HPA-Axis in Women Taking Oral Contraceptives

DEFF Research Database (Denmark)

Hertel, Johannes; König, Johanna; Homuth, Georg

2017-01-01

Using oral contraceptives has been implicated in the aetiology of stress-related disorders like depression. Here, we followed the hypothesis that oral contraceptives deregulate the HPA-axis by elevating circulating cortisol levels. We report for a sample of 233 pre-menopausal women increased...

Influence of cochlear implantation on peripheral vestibular receptor function.

Science.gov (United States)

Krause, Eike; Louza, Julia P R; Wechtenbruch, Juliane; Gürkov, Robert

2010-06-01

The objectives of this study were 1) to assess the influence of a cochlear implantation on peripheral vestibular receptor function in the inner ear in the implant and in the nonimplant side, and 2) to analyze a possible correlation with resulting vertigo symptoms. Prospective clinical study. Cochlear implant center at tertiary referral hospital. A total of 32 patients, aged 15 to 83 years, undergoing cochlear implantation were assessed pre- and postoperatively for caloric horizontal semicircular canal response and vestibular-evoked myogenic potentials of the sacculus, and postoperatively for subjective vertigo symptoms. Patients with vertigo were compared with patients without symptoms with regard to the findings of the vestibular function tests. Cochlear implantation represents a significant risk factor for horizontal semicircular canal impairment (P 0.05). Cochlear implantation is a relevant risk factor for damage of peripheral vestibular receptor function. Therefore, preservation not only of residual hearing function but also of vestibular function should be aimed for, by using minimally invasive surgical techniques. Copyright 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.

Inflammation Is an Important Covariate for the Crosstalk of Sleep and the HPA Axis in Rheumatoid Arthritis.

Science.gov (United States)

Straub, Rainer H; Detert, Jaqueline; Dziurla, René; Fietze, Ingo; Loeschmann, Peter-Andreas; Burmester, Gerd R; Buttgereit, Frank

2017-01-01

Rheumatoid arthritis (RA) patients have sleep problems, and inflammation influences sleep. We demonstrated that sleep quality improves during intensified treatment with methotrexate (MTX) or etanercept (ETA). Since the hypothalamic-pituitary-adrenal (HPA) axis is involved in sleep regulation, this study investigated the interrelation between sleep parameters, inflammation as objectified by C-reactive protein (CRP), and serum cortisol and adrenocorticotropic hormone (ACTH) levels. Thirty-one eligible patients (disease activity score, DAS28CRP ≥3.2) participated in a 16-week, open, prospective study of HPA axis outcomes. MTX was initiated in 15 patients (female-to-male ratio 9/6) and ETA in 16 patients (14/2). Clinical, laboratory (after polysomnography [PSG] between 8 and 9 a.m.), sleep (PSG), and HPA axis outcome parameters (after PSG between 8 and 9 a.m.) were recorded at baseline and week 16. Clinical characteristics of patients markedly improved throughout the study (e.g., DAS28CRP: p Sleep efficiency and wake time after sleep onset markedly improved in the ETA group. Serum cortisol and ACTH did not change during observation. At baseline, serum cortisol levels were negatively correlated to sleep efficiency; this may depend on inflammation, because controlling for CRP eliminated this negative correlation. After ETA treatment, serum cortisol had a high positive correlation with total sleep time, sleep efficiency, and a negative correlation with wake time before and after sleep onset, which was not eliminated by controlling for CRP. In RA patients, the data indicate that inflammation is an important covariate for the crosstalk of sleep and the HPA axis. © 2017 S. Karger AG, Basel.

Molecular cloning and pharmacology of functionally distinct isoforms of the human histamine H(3) receptor

DEFF Research Database (Denmark)

Wellendorph, Petrine; Goodman, M W; Burstein, E S

2002-01-01

The pharmacology of histamine H(3) receptors suggests the presence of distinct receptor isoforms or subtypes. We herein describe multiple, functionally distinct, alternatively spliced isoforms of the human H(3) receptor. Combinatorial splicing at three different sites creates at least six distinct...... receptor isoforms, of which isoforms 1, 2, and 4, encode functional proteins. Detailed pharmacology on isoforms 1 (unspliced receptor), and 2 (which has an 80 amino acid deletion within the third intracellular loop of the protein) revealed that both isoforms displayed robust responses to a series of known...... revealed a rank order of potency at both isoforms of clobenpropit>iodophenpropit>thioperamide, and these drugs are fivefold less potent at isoform 2 than isoform 1. To further explore the pharmacology of H(3) receptor function, we screened 150 clinically relevant neuropsychiatric drugs for H(3) receptor...

Plant growth enhancement and associated physiological responses are coregulated by ethylene and gibberellin in response to harpin protein Hpa1

OpenAIRE

Li, Xiaojie; Han, Bing; Xu, Manyu; Han, Liping; Zhao, Yanying; Liu, Zhilan; Dong, Hansong; Zhang, Chunling

2014-01-01

The harpin protein Hpa1 produced by the bacterial blight pathogen of rice induces several growth-promoting responses in plants, activating the ethylene signaling pathway, increasing photosynthesis rates and EXPANSIN (EXP) gene expression levels, and thereby enhancing the vegetative growth. This study was attempted to analyze any mechanistic connections among the above and the role of gibberellin in these responses. Hpa1-induced growth enhancement was evaluated in Arabidopsis, tomato, and rice...

Pre-gestational stress reduces the ratio of 5-HIAA to 5-HT and the expression of 5-HT1A receptor and serotonin transporter in the brain of foetal rat

Directory of Open Access Journals (Sweden)

Huang Yuejun

2012-02-01

Full Text Available Abstract Background Many studies have found that stress before or during pregnancy is linked to an increased incidence of behavioural disorders in offspring. However, few studies have investigated hypothalamic-pituitary-adrenal (HPA axis activity and the serotonergic system as a consequence of pregestational stress. In the present study, we investigated the effect of pre-gestational stress on HPA axis activity in maternal rats and their foetuses and examined whether changes in HPA axis activity of maternal rats produced functional changes in the serotonergic system in the brain of foetuses. Results We used the behavioural tests to assess the model of chronic unpredictable stress (CUS in maternal rats. We found the activity in the open field and sucrose consumption was lower for rats with CUS than for the controls. Body weight but not brain weight was higher for control foetuses than those from the CUS group. Serum corticosterone and corticotrophin-releasing hormone levels were significantly higher for mothers with CUS before pregnancy and their foetuses than for the controls. Levels of 5-hydroxytryptamine (5-HT were higher in the hippocampus and hypothalamus of foetuses in the CUS group than in the controls, and 5-hydroxyindoleacetic acid (5-HIAA levels were lower in the hippocampus in foetuses in the CUS group than in the control group. Levels of 5-HIAA in the hypothalamus did not differ between foetuses in the CUS group and in the control group. The ratio of 5-HIAA to 5-HT was significantly lower for foetuses in the CUS group than in the control group. Levels of 5-HT1A receptor were significantly lower in the foetal hippocampus in the CUS group than in the control group, with no significant difference in the hypothalamus. The levels of serotonin transporter (SERT were lower in both the foetal hippocampus and foetal hypothalamus in the CUS group than in the control group. Conclusions Our data demonstrate that pre-gestational stress alters HPA

High throughput mutagenesis for identification of residues regulating human prostacyclin (hIP) receptor expression and function.

Science.gov (United States)

Bill, Anke; Rosethorne, Elizabeth M; Kent, Toby C; Fawcett, Lindsay; Burchell, Lynn; van Diepen, Michiel T; Marelli, Anthony; Batalov, Sergey; Miraglia, Loren; Orth, Anthony P; Renaud, Nicole A; Charlton, Steven J; Gosling, Martin; Gaither, L Alex; Groot-Kormelink, Paul J

2014-01-01

The human prostacyclin receptor (hIP receptor) is a seven-transmembrane G protein-coupled receptor (GPCR) that plays a critical role in vascular smooth muscle relaxation and platelet aggregation. hIP receptor dysfunction has been implicated in numerous cardiovascular abnormalities, including myocardial infarction, hypertension, thrombosis and atherosclerosis. Genomic sequencing has discovered several genetic variations in the PTGIR gene coding for hIP receptor, however, its structure-function relationship has not been sufficiently explored. Here we set out to investigate the applicability of high throughput random mutagenesis to study the structure-function relationship of hIP receptor. While chemical mutagenesis was not suitable to generate a mutagenesis library with sufficient coverage, our data demonstrate error-prone PCR (epPCR) mediated mutagenesis as a valuable method for the unbiased screening of residues regulating hIP receptor function and expression. Here we describe the generation and functional characterization of an epPCR derived mutagenesis library compromising >4000 mutants of the hIP receptor. We introduce next generation sequencing as a useful tool to validate the quality of mutagenesis libraries by providing information about the coverage, mutation rate and mutational bias. We identified 18 mutants of the hIP receptor that were expressed at the cell surface, but demonstrated impaired receptor function. A total of 38 non-synonymous mutations were identified within the coding region of the hIP receptor, mapping to 36 distinct residues, including several mutations previously reported to affect the signaling of the hIP receptor. Thus, our data demonstrates epPCR mediated random mutagenesis as a valuable and practical method to study the structure-function relationship of GPCRs.

High throughput mutagenesis for identification of residues regulating human prostacyclin (hIP receptor expression and function.

Directory of Open Access Journals (Sweden)

Anke Bill

Full Text Available The human prostacyclin receptor (hIP receptor is a seven-transmembrane G protein-coupled receptor (GPCR that plays a critical role in vascular smooth muscle relaxation and platelet aggregation. hIP receptor dysfunction has been implicated in numerous cardiovascular abnormalities, including myocardial infarction, hypertension, thrombosis and atherosclerosis. Genomic sequencing has discovered several genetic variations in the PTGIR gene coding for hIP receptor, however, its structure-function relationship has not been sufficiently explored. Here we set out to investigate the applicability of high throughput random mutagenesis to study the structure-function relationship of hIP receptor. While chemical mutagenesis was not suitable to generate a mutagenesis library with sufficient coverage, our data demonstrate error-prone PCR (epPCR mediated mutagenesis as a valuable method for the unbiased screening of residues regulating hIP receptor function and expression. Here we describe the generation and functional characterization of an epPCR derived mutagenesis library compromising >4000 mutants of the hIP receptor. We introduce next generation sequencing as a useful tool to validate the quality of mutagenesis libraries by providing information about the coverage, mutation rate and mutational bias. We identified 18 mutants of the hIP receptor that were expressed at the cell surface, but demonstrated impaired receptor function. A total of 38 non-synonymous mutations were identified within the coding region of the hIP receptor, mapping to 36 distinct residues, including several mutations previously reported to affect the signaling of the hIP receptor. Thus, our data demonstrates epPCR mediated random mutagenesis as a valuable and practical method to study the structure-function relationship of GPCRs.

Xenobiotic Receptor-Mediated Regulation of Intestinal Barrier Function and Innate Immunity

Directory of Open Access Journals (Sweden)

Harmit S. Ranhotra

2016-07-01

Full Text Available The molecular basis for the regulation of the intestinal barrier is a very fertile research area. A growing body of knowledge supports the targeting of various components of intestinal barrier function as means to treat a variety of diseases, including the inflammatory bowel diseases. Herein, we will summarize the current state of knowledge of key xenobiotic receptor regulators of barrier function, highlighting recent advances, such that the field and its future are succinctly reviewed. We posit that these receptors confer an additional dimension of host-microbe interaction in the gut, by sensing and responding to metabolites released from the symbiotic microbiota, in innate immunity and also in host drug metabolism. The scientific evidence for involvement of the receptors and its molecular basis for the control of barrier function and innate immunity regulation would serve as a rationale towards development of non-toxic probes and ligands as drugs.

Hydrogen Exchange Mass Spectrometry of Functional Membrane-bound Chemotaxis Receptor Complexes

Science.gov (United States)

Koshy, Seena S.; Eyles, Stephen J.; Weis, Robert M.; Thompson, Lynmarie K.

2014-01-01

The transmembrane signaling mechanism of bacterial chemotaxis receptors is thought to involve changes in receptor conformation and dynamics. The receptors function in ternary complexes with two other proteins, CheA and CheW, that form extended membrane-bound arrays. Previous studies have shown that attractant binding induces a small (~2 Å) piston displacement of one helix of the periplasmic and transmembrane domains towards the cytoplasm, but it is not clear how this signal propagates through the cytoplasmic domain to control the kinase activity of the CheA bound at the membrane-distal tip, nearly 200 Å away. The cytoplasmic domain has been shown to be highly dynamic, which raises the question of how a small piston motion could propagate through a dynamic domain to control CheA kinase activity. To address this, we have developed a method for measuring dynamics of the receptor cytoplasmic fragment (CF) in functional complexes with CheA and CheW. Hydrogen exchange mass spectrometry (HDX-MS) measurements of global exchange of CF demonstrate that CF exhibits significantly slower exchange in functional complexes than in solution. Since the exchange rates in functional complexes are comparable to that of other proteins of similar structure, the CF appears to be a well-structured protein within these complexes, which is compatible with its role in propagating a signal that appears to be a tiny conformational change in the periplasmic and transmembrane domains of the receptor. We also demonstrate the feasibility of this protocol for local exchange measurements, by incorporating a pepsin digest step to produce peptides with 87% sequence coverage and only 20% back exchange. This method extends HDX-MS to membrane-bound functional complexes without detergents that may perturb the stability or structure of the system. PMID:24274333

Functional expression of the 5-HT1c receptor in neuronal and nonneuronal cells

International Nuclear Information System (INIS)

Julius, D.; MacDermott, A.B.; Jessel, T.M.; Huang, K.; Molineaux, S.; Schieren, I.; Axel, R.

1988-01-01

The isolation of the genes encoding the multiple serotonin receptor subtypes and the ability to express these receptors in new cellular environments will help to elucidate the molecular mechanisms of action of serotonin in the mammalian brain. The cloning of most neurotransmitter receptors has required the purification of receptor, the determination of partial protein sequence, and the synthesis of oligonucleotide probes with which to obtain cDNA or genomic clones. However, the serotonin receptors have not been purified and antibodies have not been generated. The authors therefore designed a cDNA expression system that permits the identification of functional cDNA clones encoding serotonin receptors in the absence of protein sequence information. They have combined cloning in RNA expression vectors with an electrophysiological assay in oocytes to isolate a functional cDNA clone encoding the entire 5-HT 1c receptor. The sequence of this clone reveals that the 5-HT 1c receptor belongs to a family of G-protein-coupled receptors that are thought to traverse the membrane seven times. Mouse fibroblasts transformed with this clone bind serotonergic ligands and respond to serotonin with an elevation in intracellular calcium. Moreover, in situ hybridization and Northern blot analysis indicate that the 5-HT 1c receptor mRNA is expressed in a wide variety of neurons in the rat central nervous system, suggesting that this receptor plays a prominent role in neuronal function

Structural and functional plasticity of the luteinizing hormone/choriogonadotrophin receptor.

Science.gov (United States)

Troppmann, Britta; Kleinau, Gunnar; Krause, Gerd; Gromoll, Jörg

2013-01-01

BACKGROUND In recent years it became evident that several types of the luteinizing hormone/choriogonadotrophin receptor (LHCGR) exist. In addition to the classical receptor type known in rodents, an LHCGR type containing an additional exon is present in primates and humans. This specific exon 6A introduces a hitherto unknown regulatory pathway of the LHCGR at the transcriptional level which can lead to the expression of an alternative protein covering the extracellular part only. Furthermore, an LHCGR type lacking exon 10 at the mRNA and protein levels has been described in the New World primate lineage, giving rise to an additional receptor type in which amino acids of the extracellular hinge region connecting the leucine-rich repeat domain and transmembrane domain are missing. METHODS Topic-related information was retrieved by systematic searches using Medline/PubMed. Structural homology models were retrieved from a glycoprotein hormone receptors web application and from recent publications. RESULTS In a novel approach, we combine functional aspects with three-dimensional properties of the LHCGR and the different receptor types to deduce causative relationships between these two parameters. On this basis, the physiological impact and patho-physiological consequences of the different LHCGR types are inferred. CONCLUSIONS The complex system of different LHCGR types and two corresponding hormones (LH and CG) represents a major challenge for future studies on selective hormone binding, signal transduction and receptor regulation. The presence of these naturally occurring LHCGR types requires re-examining of our present view on receptor function, experimental set-ups and data interpretation, but also offers new clinical approaches to interfere with LH/CG action in humans.

Structure, function and physiological consequences of virally encoded chemokine seven transmembrane receptors

DEFF Research Database (Denmark)

Rosenkilde, M M; Smit, M J; Waldhoer, M

2008-01-01

A number of human and animal herpes viruses encode G-protein coupled receptors with seven transmembrane (7TM) segments-most of which are clearly related to human chemokine receptors. It appears, that these receptors are used by the virus for immune evasion, cellular transformation, tissue targeting...... pathogenesis is still poorly understood. Here we focus on the current knowledge of structure, function and trafficking patterns of virally encoded chemokine receptors and further address the putative roles of these receptors in virus survival and host -cell and/or -immune system modulation. Finally, we...

Identification of functional VEGF receptors on human platelets.

Science.gov (United States)

Selheim, Frode; Holmsen, Holm; Vassbotn, Flemming S

2002-02-13

Platelets secrete platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) upon stimulation. We have demonstrated that platelets have functionally active PDGF alpha-receptors, a transmembrane tyrosine kinase involved in negative feedback regulation. Here we demonstrate the presence of the related VEGF receptors fms-like tyrosine kinase-1 and kinase-insert domain region on human platelets. VEGF itself did not cause platelet aggregation. However, addition of exogenous VEGF to SFRLLN or thrombin-stimulated platelets potentiated platelet aggregation. Moreover, thrombin-induced phosphoinositide 3-kinase and mitogen-activated protein kinase activity were enhanced in the presence of VEGF.

Climate Prediction Center (CPC)Area-averaged 850-hPa Western Pacific Trade Wind Anomalies

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It is the 850-hPa trade wind anomalies averaged over the area 5oN ? 5oS, 135oE-180o (western equatorial...

Climate Prediction Center (CPC)Area-averaged 850-hPa Eastern Pacific Trade Wind Anomalies

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It is the 850-hPa trade wind anomalies averaged over the area 5oN ? 5oS, 135oW-120oW (eastern...

Climate Prediction Center (CPC)Area-averaged 850-hPa Central Pacific Trade Wind Anomalies

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It is the 850-hPa trade wind anomalies averaged over the area 5oN ? 5oS, 175oW-140oW (central...

Construction of a recombinant Lactococcus lactis strain expressing a fusion protein of Omp22 and HpaA from Helicobacter pylori for oral vaccine development.

Science.gov (United States)

Zhang, Rongguang; Duan, Guangcai; Shi, Qingfeng; Chen, Shuaiyin; Fan, Qingtang; Sun, Nan; Xi, Yuanlin

2016-11-01

To develop orally administrated anti-Helicobacter pylori vaccination, a Lactococcus lactis strain was genetically constructed for fusion expression of H. pylori protective antigens HpaA and Omp22. The fusion gene of omp22 and hpaA with an adapter encoding three glycines was cloned from a plasmid pMAL-c2x-omp22-hpaA into Escherichia coli MC1061 and L. lactis NZ3900 successively using a shutter vector pNZ8110. Expression of the fusion gene in L. lactis was induced with nisin resulting in production of proteins with molecular weights of 50 and 28 kDa. Both of them were immunoreactive with mouse anti-H. pylori sera as determined via western blotting. Oral vaccination of BALB/c mice using the L. lactis strain carrying pNZ8110-omp22-hpaA elicited significant systematic humoral immune response (P lactis with immunogenicity. This is a considerable step towards H. pylori vaccines.

Expanding the Annual Irrigation Maps (AIM) Product to the entire High Plains Aquifer (HPA): Addressing the Challenges of Cotton and Deficit-Irrigated Fields

Science.gov (United States)

Rapp, J. R.; Deines, J. M.; Kendall, A. D.; Hyndman, D. W.

2017-12-01

The High Plains Aquifer (HPA) is the most extensively irrigated aquifer in the continental United States and is the largest major aquifer in North America with an area of 500,000 km2. Increased demand for agricultural products has led to expanded irrigation extent, but brought with it declining groundwater levels that have made irrigation unsustainable in some locations. Understanding these irrigation dynamics and mapping irrigated areas through time are essential for future sustainable agricultural practices and hydrological modeling. Map products using remote sensing have only recently been able to track annual dynamics at relatively high spatial resolution (30 m) for a large portion of the northern HPA. However follow-on efforts to expand these maps to the entire HPA have met with difficulty due to the challenge of distinguishing irrigation in crop types that are commonly deficit- or partially-irrigated. Expanding these maps to the full HPA requires addressing unique features of partially irrigated fields and irrigated cotton, a major water user in the southern HPA. Working in Google Earth Engine, we used all available Landsat imagery to generate annual time series of vegetation indices. We combined this information with climate covariables, planting dates, and crop specific training data to algorithmically separate fully irrigated, partially irrigated, and non-irrigated field locations. The classification scheme was then applied to produce annual maps of irrigation across the entire HPA. The extensive use of ancillary data and the "greenness" time series for the algorithmic classification generally increased accuracy relative to previous efforts. High-accuracy, representative map products of irrigation extent capable of detecting crop type and irrigation intensity within aquifers will be an essential tool to monitor the sustainability of global aquifers and to provide a scientific bases for political and economic decisions affecting those aquifers.

Influence of early life stress on later hypothalamic-pituitary-adrenal axis functioning and its covariation with mental health symptoms: a study of the allostatic process from childhood into adolescence.

Science.gov (United States)

Essex, Marilyn J; Shirtcliff, Elizabeth A; Burk, Linnea R; Ruttle, Paula L; Klein, Marjorie H; Slattery, Marcia J; Kalin, Ned H; Armstrong, Jeffrey M

2011-11-01

The hypothalamic-pituitary-adrenal (HPA) axis is a primary mechanism in the allostatic process through which early life stress (ELS) contributes to disease. Studies of the influence of ELS on children's HPA axis functioning have yielded inconsistent findings. To address this issue, the present study considers multiple types of ELS (maternal depression, paternal depression, and family expressed anger), mental health symptoms, and two components of HPA functioning (traitlike and epoch-specific activity) in a long-term prospective community study of 357 children. ELS was assessed during the infancy and preschool periods; mental health symptoms and cortisol were assessed at child ages 9, 11, 13, and 15 years. A three-level hierarchical linear model addressed questions regarding the influences of ELS on HPA functioning and its covariation with mental health symptoms. ELS influenced traitlike cortisol level and slope, with both hyper- and hypoarousal evident depending on type of ELS. Further, type(s) of ELS influenced covariation of epoch-specific HPA functioning and mental health symptoms, with a tighter coupling of HPA alterations with symptom severity among children exposed previously to ELS. Results highlight the importance of examining multiple types of ELS and dynamic HPA functioning in order to capture the allostatic process unfolding across the transition into adolescence.

Adrenocortical and behavioural response to chronic restraint stress in neurokinin-1 receptor knockout mice.

Science.gov (United States)

Delgado-Morales, Raúl; del Río, Eva; Gómez-Román, Almudena; Bisagno, Verónica; Nadal, Roser; de Felipe, Carmen; Armario, Antonio

2012-02-01

Brain substance P and its receptor (neurokinin-1, NK1) have a widespread brain distribution and are involved in an important number of behavioural and physiological responses to emotional stimuli. However, the role of NK1 receptors in the consequences of exposure to chronic stress has not been explored. The present study focused on the role of these receptors in the hypothalamic-pituitary-adrenal (HPA) response to daily repeated restraint stress (evaluated by plasma corticosterone levels), as well as on the effect of this procedure on anxiety-like behaviour, spatial learning and memory in the Morris water maze (MWM), a hippocampus-dependent task. Adult null mutant NK1-/- mice, with a C57BL/6J background, and the corresponding wild-type mice showed similar resting corticosterone levels and, also, did not differ in corticosterone response to a first restraint. Nevertheless, adaptation to the repeated stressor was faster in NK1-/- mice. Chronic restraint modestly increased anxiety-like behaviour in the light-dark test, irrespective of genotype. Throughout the days of the MWM trials, NK1-/- mice showed a similar learning rate to that of wild-type mice, but had lower levels of thigmotaxis and showed a better retention in the probe trial. Chronic restraint stress did not affect these variables in either genotype. These results indicate that deletion of the NK1 receptor does not alter behavioural susceptibility to chronic repeated stress in mice, but accelerates adaptation of the HPA axis. In addition, deletion may result in lower levels of thigmotaxis and improved short-term spatial memory, perhaps reflecting a better learning strategy in the MWM. Copyright © 2011 Elsevier Inc. All rights reserved.

Microsomal receptor for steroid hormones: functional implications for nuclear activity.

Science.gov (United States)

Muldoon, T G; Watson, G H; Evans, A C; Steinsapir, J

1988-01-01

Target tissues for steroid hormones are responsive by virtue of and to the extent of their content of functional intracellular receptors. Recent years have seen a shift in considerations of the cellular dynamics and distribution of these receptors, with current views favoring predominant intranuclear localization in the intact cell. This paper summarizes our analyses of the microsomal estrogen and androgen binding capability of rat uterine and ventral prostate tissue, respectively; these studies have revealed a set of high affinity sites that may act as a conduit for estrogen traversing the cell en route to the nucleus. These sites have many properties in common with cytosolic receptors, with the salient difference of a failure to activate to a more avid DNA-binding form under conditions which permit such activation of cytosolic receptors. The microsomal estrogen-binding proteins also have appreciable affinity for progesterone, another distinction from other known cellular estrogen receptor species. Various experimental approaches were employed to demonstrate that the microsomal receptors were not simply cytosol contaminants; the most convincing evidence is the recent successful separation of the cytosolic and microsomal forms by differential ammonium sulfate precipitation. Discrete subfractionation of subcellular components on successive sucrose gradients, with simultaneous assessments of binding capability and marker enzyme concentrations, indicates that the major portion of the binding is localized within the vesicles of the endoplasmic reticulum free of significant plasma membrane contamination. The microsomal receptors are readily solubilized by extraction with high- or low-salt-containing buffers or with steroid. The residual microsomes following such extraction have the characteristics of saturable acceptor sites for cytosolic estrogen-receptor complexes. The extent to which these sites will accept the cytosolic complexes is equal to the concentration of

Behavioral, neuroendocrine and neurochemical effects of the imidazoline I2 receptor selective ligand BU224 in naive rats and rats exposed to the stress of the forced swim test.

Science.gov (United States)

Finn, David P; Martí, Octavi; Harbuz, Michael S; Vallès, Astrid; Belda, Xavier; Márquez, Cristina; Jessop, David S; Lalies, Margaret D; Armario, Antonio; Nutt, David J; Hudson, Alan L

2003-05-01

There is evidence for alterations in imidazoline(2) (I(2)) receptor density in depressed patients. Selective I(2) receptor ligands modulate central monoamine levels and activate the hypothalamo-pituitary-adrenal (HPA) axis and may have potential as antidepressants. To study the behavioral effects of the selective I(2) receptor ligand BU224 in the rat forced swim test (FST) and its effects on the HPA axis and central monoaminergic responses. Rats received saline or BU224 (10 mg/kg IP) 24, 18 and 1 h prior to 15 min exposure to the FST. Saline- and BU224-treated non-stressed groups were included. Time spent immobile, struggling and swimming calmly was measured. Plasma adrenocorticotrophic hormone (ACTH) and corticosterone levels 90 min post-BU224 were measured in addition to tissue levels of monoamines and metabolites in the frontal cortex, hippocampus and hypothalamus. Administration of BU224 significantly reduced immobility and increased mild swimming without affecting struggling. Exposure to the FST significantly increased plasma ACTH and corticosterone levels. BU224 administration also increased ACTH and potentiated the ACTH response to FST with no effect on corticosterone. BU224 administration significantly increased frontal cortex 5-hydroxytryptamine (5-HT) levels and decreased 5-HT turnover in the frontal cortex and hypothalamus of rats exposed to FST. In non-stressed rats, BU224 decreased 5-HT turnover in the hippocampus and hypothalamus and decreased norepinephrine turnover in the frontal cortex. The selective I(2) receptor ligand BU224 reduces immobility of rats in the FST, indicative of antidepressant-like activity. This effect is accompanied by alterations in HPA axis and central monoaminergic activity.

Captodiamine, a putative antidepressant, enhances hypothalamic BDNF expression in vivo by synergistic 5-HT2c receptor antagonism and sigma-1 receptor agonism.

Science.gov (United States)

Ring, Rebecca M; Regan, Ciaran M

2013-10-01

The putative antidepressant captodiamine is a 5-HT2c receptor antagonist and agonist at sigma-1 and D3 dopamine receptors, exerts an anti-immobility action in the forced swim paradigm, and enhances dopamine turnover in the frontal cortex. Captodiamine has also been found to ameliorate stress-induced anhedonia, reduce the associated elevations of hypothalamic corticotrophin-releasing factor (CRF) and restore the reductions in hypothalamic BDNF expression. Here we demonstrate chronic administration of captodiamine to have no significant effect on hypothalamic CRF expression through sigma-1 receptor agonism; however, both sigma-1 receptor agonism or 5-HT2c receptor antagonism were necessary to enhance BDNF expression. Regulation of BDNF expression by captodiamine was associated with increased phosphorylation of transcription factor CREB and mediated through sigma-1 receptor agonism but blocked by 5-HT2c receptor antagonism. The existence of two separate signalling pathways was confirmed by immunolocalisation of each receptor to distinct cell populations in the paraventricular nucleus of the hypothalamus. Increased BDNF induced by captodiamine was also associated with enhanced expression of synapsin, but not PSD-95, suggesting induction of long-term structural plasticity between hypothalamic synapses. These unique features of captodiamine may contribute to its ability to ameliorate stress-induced anhedonia as the hypothalamus plays a prominent role in regulating HPA axis activity.

Characterization of Angiotensin II Molecular Determinants Involved in AT1 Receptor Functional Selectivity.

Science.gov (United States)

Domazet, Ivana; Holleran, Brian J; Richard, Alexandra; Vandenberghe, Camille; Lavigne, Pierre; Escher, Emanuel; Leduc, Richard; Guillemette, Gaétan

2015-06-01

The octapeptide angiotensin II (AngII) exerts a variety of cardiovascular effects through the activation of the AngII type 1 receptor (AT1), a G protein-coupled receptor. The AT1 receptor engages and activates several signaling pathways, including heterotrimeric G proteins Gq and G12, as well as the extracellular signal-regulated kinases (ERK) 1/2 pathway. Additionally, following stimulation, βarrestin is recruited to the AT1 receptor, leading to receptor desensitization. It is increasingly recognized that specific ligands selectively bind and favor the activation of some signaling pathways over others, a concept termed ligand bias or functional selectivity. A better understanding of the molecular basis of functional selectivity may lead to the development of better therapeutics with fewer adverse effects. In the present study, we developed assays allowing the measurement of six different signaling modalities of the AT1 receptor. Using a series of AngII peptide analogs that were modified in positions 1, 4, and 8, we sought to better characterize the molecular determinants of AngII that underlie functional selectivity of the AT1 receptor in human embryonic kidney 293 cells. The results reveal that position 1 of AngII does not confer functional selectivity, whereas position 4 confers a bias toward ERK signaling over Gq signaling, and position 8 confers a bias toward βarrestin recruitment over ERK activation and Gq signaling. Interestingly, the analogs modified in position 8 were also partial agonists of the protein kinase C (PKC)-dependent ERK pathway via atypical PKC isoforms PKCζ and PKCι. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Stabilization of functional recombinant cannabinoid receptor CB(2 in detergent micelles and lipid bilayers.

Directory of Open Access Journals (Sweden)

Krishna Vukoti

Full Text Available Elucidation of the molecular mechanisms of activation of G protein-coupled receptors (GPCRs is among the most challenging tasks for modern membrane biology. For studies by high resolution analytical methods, these integral membrane receptors have to be expressed in large quantities, solubilized from cell membranes and purified in detergent micelles, which may result in a severe destabilization and a loss of function. Here, we report insights into differential effects of detergents, lipids and cannabinoid ligands on stability of the recombinant cannabinoid receptor CB(2, and provide guidelines for preparation and handling of the fully functional receptor suitable for a wide array of downstream applications. While we previously described the expression in Escherichia coli, purification and liposome-reconstitution of multi-milligram quantities of CB(2, here we report an efficient stabilization of the recombinant receptor in micelles - crucial for functional and structural characterization. The effects of detergents, lipids and specific ligands on structural stability of CB(2 were assessed by studying activation of G proteins by the purified receptor reconstituted into liposomes. Functional structure of the ligand binding pocket of the receptor was confirmed by binding of (2H-labeled ligand measured by solid-state NMR. We demonstrate that a concerted action of an anionic cholesterol derivative, cholesteryl hemisuccinate (CHS and high affinity cannabinoid ligands CP-55,940 or SR-144,528 are required for efficient stabilization of the functional fold of CB(2 in dodecyl maltoside (DDM/CHAPS detergent solutions. Similar to CHS, the negatively charged phospholipids with the serine headgroup (PS exerted significant stabilizing effects in micelles while uncharged phospholipids were not effective. The purified CB(2 reconstituted into lipid bilayers retained functionality for up to several weeks enabling high resolution structural studies of this GPCR at

Enhancing NMDA Receptor Function: Recent Progress on Allosteric Modulators

Directory of Open Access Journals (Sweden)

Lulu Yao

2017-01-01

Full Text Available The N-methyl-D-aspartate receptors (NMDARs are subtype glutamate receptors that play important roles in excitatory neurotransmission and synaptic plasticity. Their hypo- or hyperactivation are proposed to contribute to the genesis or progression of various brain diseases, including stroke, schizophrenia, depression, and Alzheimer’s disease. Past efforts in targeting NMDARs for therapeutic intervention have largely been on inhibitors of NMDARs. In light of the discovery of NMDAR hypofunction in psychiatric disorders and perhaps Alzheimer’s disease, efforts in boosting NMDAR activity/functions have surged in recent years. In this review, we will focus on enhancing NMDAR functions, especially on the recent progress in the generation of subunit-selective, allosteric positive modulators (PAMs of NMDARs. We shall also discuss the usefulness of these newly developed NMDAR-PAMs.

Effects of resistance exercise on the HPA axis response to psychological stress during short-term smoking abstinence in men.

Science.gov (United States)

Ho, Jen-Yu; Kraemer, William J; Volek, Jeff S; Vingren, Jakob L; Fragala, Maren S; Flanagan, Shawn D; Maladouangdock, Jesse; Szivak, Tunde K; Hatfield, Disa L; Comstock, Brett A; Dunn-Lewis, Courtenay; Ciccolo, Joseph T; Maresh, Carl M

2014-03-01

The purpose of this study was to examine the effects of resistance exercise on the hypothalamic-pituitary-adrenal axis (HPA) response to mental challenge, withdrawal symptoms, urge to smoke, and cognitive stress during 24-hour smoking abstinence. 8 sedentary smokers (mean±SD age: 20.1±1.7y; height: 171.6±10.8cm; body mass: 70.4±12.0kg; smoking history: 2.9±0.8y) completed a 24-hour ad libitum smoking trial (SMO) followed by two 24-hour smoking abstinence trials. During abstinence trials, participants performed six whole body resistance exercises (EX) or a control condition (CON) in the morning, followed by mental challenge tasks in the afternoon. Plasma adrenocorticotropin hormone (ACTH), and salivary and serum cortisol were measured during each visit at rest (REST), and then before (PRE-EX), immediately after (IP-EX), and 30min after exercise (30-EX); and before (PRE-MC), immediately after (IP-MC), and 30min after mental challenge (30-MC). Resistance exercise significantly (p≤0.05) elevated plasma ACTH and serum cortisol at IP-EX during EX compared with SMO and CON trials. Resting ACTH, salivary and serum cortisol concentrations at Pre-MC did not differ between EX and CON trials. The HPA axis response to mental challenge was similar after EX and CON trials. Finally, resistance exercise did not reduce withdrawal symptoms, urge to smoke, or stress. Resistance exercise did not substantially alter resting HPA hormones or the HPA response to mental challenge tasks during 24h of smoking abstinence. © 2013.

Functional Consequences of Glucagon-like Peptide-1 Receptor Cross-talk and Trafficking

DEFF Research Database (Denmark)

Roed, Sarah Noerklit; Nøhr, Anne Cathrine; Wismann, Pernille

2015-01-01

The signaling capacity of seven-transmembrane/G-protein-coupled receptors (7TM/GPCRs) can be regulated through ligand-mediated receptor trafficking. Classically, the recycling of internalized receptors is associated with resensitization, whereas receptor degradation terminates signaling. We have......) and glucagon (GCGR) receptors. The interaction and cross-talk between coexpressed receptors is a wide phenomenon of the 7TM/GPCR superfamily. Numerous reports show functional consequences for signaling and trafficking of the involved receptors. On the basis of the high structural similarity and tissue...... coexpression, we here investigated the potential cross-talk between GLP-1R and GIPR or GCGR in both trafficking and signaling pathways. Using a real-time time-resolved FRET-based internalization assay, we show that GLP-1R, GIPR, and GCGR internalize with differential properties. Remarkably, upon coexpression...

[GPCRs heterodimerization: a new way towards the discovery of function for the orphan receptors?].

Science.gov (United States)

Levoye, Angélique; Jockers, Ralf

2007-01-01

G protein-coupled receptors (GPCRs), also called seven transmembrane domain (7TM) proteins, represent the largest family of cell surface receptors. GPCRs control a variety of physiological processes, are involved in multiple diseases and are major drug targets. Despite a vast effort of academic and industrial research, more than one hundred receptors remain orphans. These orphan GPCRs offer a great potential for drug discovery, as almost 60% of currently prescribed drugs target GPCRs. Deorphenization strategies have concentrated mainly on the identification of the natural ligands of these proteins. Recent advances have shown that orphan GPCRs, similar to orphan nuclear receptors, can regulate the function of non-orphan receptors by heterodimerization. These findings not only help to better understand the extraordinary diversity of GPCRs, but also open new perspectives for the identification of the function of these orphan receptors that hold great therapeutic potential.

Functional Studies of Sex Pheromone Receptors in Asian Corn Borer Ostrinia furnacalis

Directory of Open Access Journals (Sweden)

Wei Liu

2018-05-01

Full Text Available Lepidopteran insects use sex pheromones for sexual communication. Pheromone receptors expressed on peripheral olfactory receptor neurons (ORNs are critical part to detect the sex pheromones. In genus Ostrinia, several pheromone receptors were functional analyzed in O. nubilalis and O. scapulalis but the knowledge in O. furnacalis was rare. In this study, seven pheromone receptors were deorphanized by heterologous expression system of Xenopus oocytes. Functional types of sensilla trichoidea were classified by single sensillum recordings to interpret the response pattern of olfactory sensory neurons to Ostrinia pheromone components. OfurOR4 and OfurOR6 responded to the major sex pheromone Z/E12-14:OAc. OfurOR4 is the main receptor for both Z/E12-14:OAc and OfurOR6 mainly responded to E12-14:OAc. Functional differentiation of gene duplication were found between OfurOR5a and OfurOR5b. OfurOR5b showed a broad response to most of the pheromone components in O. furnacalis, whereas OfurOR5a was found without ligands. OfurOR7 showed a specific response to Z9-14:OAc and OfurOR8 mainly responded to Z11-14:OAc and E11-14:OAc. OfurOR3 did not respond to any pheromone components. Our results improved the current knowledge of pheromone reception in Ostrinia species which may contribute to speciation.

Angiotensin II Type 2 Receptor and Receptor Mas Are Colocalized and Functionally Interdependent in Obese Zucker Rat Kidney

DEFF Research Database (Denmark)

Patel, Sanket N; Ali, Quaisar; Samuel, Preethi

2017-01-01

The actions of angiotensin II type 2 receptor (AT2R) and the receptor Mas (MasR) are complex but show similar pronatriuretic function; particularly, AT2R expression and natriuretic function are enhanced in obese/diabetic rat kidney. In light of some reports suggesting a potential positive...... interaction between these receptors, we tested hypothesis that renal AT2R and MasR physically interact and are interdependent to stimulate cell signaling and promote natriuresis in obese rats. We found that infusion of AT2R agonist C21 in obese Zucker rats (OZR) increased urine flow and urinary Na excretion...... coimmunoprecipitated with MasR in cortical homogenate of OZR. Immunoblotting of cortical homogenate cross-linked with zero-length oxidative (sulfhydryl groups) cross-linker cupric-phenanthroline revealed a shift of AT2R and MasR bands upward with overlapping migration for their complexes which were sensitive...

Calcium is the switch in the moonlighting dual function of the ligand-activated receptor kinase phytosulfokine receptor 1

KAUST Repository

Muleya, Victor

2014-09-23

Background: A number of receptor kinases contain guanylate cyclase (GC) catalytic centres encapsulated in the cytosolic kinase domain. A prototypical example is the phytosulfokine receptor 1 (PSKR1) that is involved in regulating growth responses in plants. PSKR1 contains both kinase and GC activities however the underlying mechanisms regulating the dual functions have remained elusive. Findings: Here, we confirm the dual activity of the cytoplasmic domain of the PSKR1 receptor. We show that mutations within the guanylate cyclase centre modulate the GC activity while not affecting the kinase catalytic activity. Using physiologically relevant Ca2+ levels, we demonstrate that its GC activity is enhanced over two-fold by Ca2+ in a concentration-dependent manner. Conversely, increasing Ca2+ levels inhibits kinase activity up to 500-fold at 100 nM Ca2+. Conclusions: Changes in calcium at physiological levels can regulate the kinase and GC activities of PSKR1. We therefore propose a functional model of how calcium acts as a bimodal switch between kinase and GC activity in PSKR1 that could be relevant to other members of this novel class of ligand-activated receptor kinases.

p75 Neurotrophin Receptor in the Skin: Beyond Its Neurotrophic Function.

Science.gov (United States)

Pincelli, Carlo

2017-01-01

p75 neurotrophin receptor (p75 NTR ), also known as CD271, is the low-affinity receptor that, together with the tyrosine kinase receptor tropomyosin-receptor kinase (Trk), mediate neurotrophin (NT) functions. Beside their classic role in skin innervation, NT and their receptors constitute a complex cutaneous network associated with a number of autocrine and paracrine activities. In this context, the role of p75 NTR is becoming more and more important. This review will focus on the intriguing functions of p75 NTR in healthy and diseased skin. First, p75 NTR counterbalances the proliferative and survival activities of its cognate receptor Trk by inducing keratinocyte apoptosis. In addition, p75 NTR identifies an early transit-amplifying (TA) keratinocyte population and plays a critical role in keratinocyte stem cell transition to its progeny as well as in epidermal differentiation. p75 NTR is absent in psoriatic TA cells, thus rendering these cells resistant to apoptosis. On the other hand, p75 NTR infection restores NT-induced apoptosis in psoriatic keratinocytes. Taken together, these results provide evidence for a critical role of p75 NTR in epidermal homeostasis, while its lack may account for the TA defect in psoriasis. While the issue of p75 NTR as a marker of melanoma initiating cells is still to be solved, there is strong evidence that downregulation of this receptor is a precondition to melanoma invasion and metastasis in vitro and in vivo . All in all, this review points to p75 NTR as a major actor in both physiologic and pathologic conditions at the skin level.

Integrating TRPV1 Receptor Function with Capsaicin Psychophysics

Directory of Open Access Journals (Sweden)

Gregory Smutzer

2016-01-01

Full Text Available Capsaicin is a naturally occurring vanilloid that causes a hot, pungent sensation in the human oral cavity. This trigeminal stimulus activates TRPV1 receptors and stimulates an influx of cations into sensory cells. TRPV1 receptors function as homotetramers that also respond to heat, proinflammatory substances, lipoxygenase products, resiniferatoxin, endocannabinoids, protons, and peptide toxins. Kinase-mediated phosphorylation of TRPV1 leads to increased sensitivity to both chemical and thermal stimuli. In contrast, desensitization occurs via a calcium-dependent mechanism that results in receptor dephosphorylation. Human psychophysical studies have shown that capsaicin is detected at nanomole amounts and causes desensitization in the oral cavity. Psychophysical studies further indicate that desensitization can be temporarily reversed in the oral cavity if stimulation with capsaicin is resumed at short interstimulus intervals. Pretreatment of lingual epithelium with capsaicin modulates the perception of several primary taste qualities. Also, sweet taste stimuli may decrease the intensity of capsaicin perception in the oral cavity. In addition, capsaicin perception and hedonic responses may be modified by diet. Psychophysical studies with capsaicin are consistent with recent findings that have identified TRPV1 channel modulation by phosphorylation and interactions with membrane inositol phospholipids. Future studies will further clarify the importance of capsaicin and its receptor in human health and nutrition.

Expression and function of the human estrogen receptor in yeast

International Nuclear Information System (INIS)

White, J.H.; Metzger, D.; Chambon, P.

1988-01-01

Gene expression in eukaryotes is regulated at many levels. Moreover, there is increasing evidence that the basic control mechanisms of transcription initiation have been conserved across the range of eukaryotes from yeast to man. In vertebrates, the nuclear receptors, whose activity is dependent on the binding of specific ligands, stimulate transcription by interacting with specific cis-acting sequences and display all of the hallmarks of inducible enhancer factors. Alignment of their amino acid sequences indicates that they are composed of a series of conserved domains. The domain structure of the human estrogen receptor (hER) is typical of receptor proteins. Region C, containing two putative zinc fingers, comprises the DNA-binding domain responsible for specific recognition of estrogen response elements (ERE). Region E contains the hormone-binding domain and domain(s) responsible for transcription activation. A mutant of the hER, called HE15, which lacks the hormone-binding domain, binds DNA in vivo and in vitro but activates transcription only poorly in a constitutive manner in vivo in HeLa cells. A series of studies have demonstrated that the hormone- and DNA-binding domains of the nuclear receptors function independently. Chimeric proteins consisting of the DNA-binding domain of yeast GAL4 coupled to the hormone-binding domains of either the hER or glucocorticoid receptor element (GRE) will stimulate transcription in HeLa cells when bound to a UAS. Taken together, these results demonstrate that the hER and other nuclear receptors, as well as GAL4 and GCN4 proteins of yeast, consist of discrete and separable DNA-binding and transcription-activation functions. To investigate these striking parallels further, the authors have expressed the hER in the yeast Saccharomyces cerevisiae and have analyzed its hormone- and DNA-binding properties in vitro and its ability to stimulate transcription in vivo

Neurotransmitters activate T-cells and elicit crucial functions via neurotransmitter receptors.

Science.gov (United States)

Levite, Mia

2008-08-01

Neurotransmitters are traditionally viewed as nerve-secreted molecules that trigger or inhibit neuronal functions. Yet, neurotransmitters bind also their neurotransmitter receptors in T-cells and directly activate or suppress T-cell functions. This review focuses only on the activating effects of neurotransmitters on T-cells, primarily naïve/resting cells, and covers dopamine, glutamate, serotonin, and few neuropeptides: GnRH-I, GnRH-II, substance P, somatostatin, CGRP, and neuropeptide Y. T-cells express many neurotransmitter receptors. These are regulated by TCR-activation, cytokines, or the neurotransmitters themselves, and are upregulated/downregulated in some human diseases. The context - whether the T-cells are naïve/resting or antigen/mitogen/cytokine-activated, the T-cell subset (CD4/CD8/Th1/Th2/Teff/Treg), neurotransmitter dose (low/optimal or high/excess), exact neurotransmitter receptors expressed, and the cytokine milieu - is crucial, and can determine either activation or suppression of T-cells by the same neurotransmitter. T-cells also produce many neurotransmitters. In summary, neurotransmitters activate vital T-cell functions in a direct, potent and specific manner, and may serve for communicating between the brain and the immune system to elicit an effective and orchestrated immune function, and for new therapeutic avenues, to improve T-cell eradication of cancer and infectious organisms.

Bioorthogonal fluorescent labeling of functional G-protein-coupled receptors

DEFF Research Database (Denmark)

Tian, He; Naganathan, Saranga; Kazmi, Manija A

2014-01-01

Novel methods are required for site-specific, quantitative fluorescent labeling of G-protein-coupled receptors (GPCRs) and other difficult-to-express membrane proteins. Ideally, fluorescent probes should perturb the native structure and function as little as possible. We evaluated bioorthogonal...

How membrane lipids control the 3D structure and function of receptors

Directory of Open Access Journals (Sweden)

Jacques Fantini

2018-02-01

Full Text Available The cohabitation of lipids and proteins in the plasma membrane of mammalian cells is controlled by specific biochemical and biophysical rules. Lipids may be either constitutively tightly bound to cell-surface receptors (non-annular lipids or less tightly attached to the external surface of the protein (annular lipids. The latter are exchangeable with surrounding bulk membrane lipids on a faster time scale than that of non-annular lipids. Not only do non-annular lipids bind to membrane proteins through stereoselective mechanisms, they can also help membrane receptors acquire (or maintain a functional 3D structure. Cholesterol is the prototype of membrane lipids that finely controls the 3D structure and function of receptors. However, several other lipids such as sphingolipids may also modulate the function of membrane proteins though conformational adjustments. All these concepts are discussed in this review in the light of representative examples taken from the literature.

An energetic orphan in an endocrine tissue: a revised perspective of the function of estrogen receptor-related receptor alpha in bone and cartilage.

Science.gov (United States)

Bonnelye, Edith; Aubin, Jane E

2013-02-01

Estrogen receptor-related receptor alpha (ERRα) is an orphan nuclear receptor with sequence homology to the estrogen receptors, ERα/β, but it does not bind estrogen. ERRα not only plays a functional role in osteoblasts but also in osteoclasts and chondrocytes. In addition, the ERRs, including ERRα, can be activated by coactivators such as peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC1α and β) and are implicated in adipogenesis, fatty acid oxidation, and oxidative stress defense, suggesting that ERRα-through its activity in bone resorption and adipogenesis--may regulate the insulin and leptin pathways and contribute to aging-related changes in bone and cartilage. In this review, we discuss data on ERRα and its cellular and molecular modes of action, which have broad implications for considering the potential role of this orphan receptor in cartilage and bone endocrine function, on whole-organism physiology, and in the bone aging process. Copyright © 2013 American Society for Bone and Mineral Research.

Ebselen has lithium-like effects on central 5-HT2A receptor function.

Science.gov (United States)

Antoniadou, I; Kouskou, M; Arsiwala, T; Singh, N; Vasudevan, S R; Fowler, T; Cadirci, E; Churchill, G C; Sharp, T

2018-02-27

Lithium's antidepressant action may be mediated by inhibition of inositol monophosphatase (IMPase), a key enzyme in G q protein coupled receptor signalling. Recently, the antioxidant agent ebselen was identified as an IMPase inhibitor. Here we investigated both ebselen and lithium in models of the 5-HT 2A receptor, a G q protein coupled receptor implicated in lithium's actions. 5-HT 2A receptor function was modelled in mice by measuring the behavioural (head-twitches) and cortical immediate early gene (IEG; Arc, c-fos and Erg2 mRNA) responses to 5-HT 2A receptor agonist administration. Ebselen and lithium were administered either acutely or chronically prior to assessment of 5-HT 2A receptor function. Given the SSRI augmenting action of lithium and 5-HT 2A antagonists, ebselen was also tested for this action by co-administration with the SSRI citalopram in microdialysis (extracellular 5-HT) experiments. Acute and repeated administration of ebselen inhibited behavioural and IEG responses to the 5-HT 2A receptor agonist DOI. Repeated lithium also inhibited DOI-evoked behavioural and IEG responses. In comparison, a selective IMPase inhibitor (L-690,330) attenuated the behavioural response to DOI whereas glycogen synthase kinase inhibitor (AR-A014418) did not. Finally, ebselen increased regional brain 5-HT synthesis and enhanced the increase in extracellular 5-HT induced by citalopram. The current data demonstrate lithium-mimetic effects of ebselen in different experimental models of 5-HT 2A receptor function, likely mediated by IMPase inhibition. This evidence of lithium-like neuropharmacological effects of ebselen adds further support for the clinical testing of ebselen in mood disorder, including as an antidepressant augmenting agent. This article is protected by copyright. All rights reserved.

Activation of Brain Somatostatin Signaling Suppresses CRF Receptor-Mediated Stress Response.

Science.gov (United States)

Stengel, Andreas; Taché, Yvette F

2017-01-01

Corticotropin-releasing factor (CRF) is the hallmark brain peptide triggering the response to stress and mediates-in addition to the stimulation of the hypothalamus-pituitary-adrenal (HPA) axis-other hormonal, behavioral, autonomic and visceral components. Earlier reports indicate that somatostatin-28 injected intracerebroventricularly counteracts the acute stress-induced ACTH and catecholamine release. Mounting evidence now supports that activation of brain somatostatin signaling exerts a broader anti-stress effect by blunting the endocrine, autonomic, behavioral (with a focus on food intake) and visceral gastrointestinal motor responses through the involvement of distinct somatostatin receptor subtypes.

Recent Duplication and Functional Divergence in Parasitic Nematode Levamisole-Sensitive Acetylcholine Receptors.

Directory of Open Access Journals (Sweden)

Thomas B Duguet

2016-07-01

Full Text Available Helminth parasites rely on fast-synaptic transmission in their neuromusculature to experience the outside world and respond to it. Acetylcholine plays a pivotal role in this and its receptors are targeted by a wide variety of both natural and synthetic compounds used in human health and for the control of parasitic disease. The model, Caenorhabditis elegans is characterized by a large number of acetylcholine receptor subunit genes, a feature shared across the nematodes. This dynamic family is characterized by both gene duplication and loss between species. The pentameric levamisole-sensitive acetylcholine receptor has been characterized from C. elegans, comprised of five different subunits. More recently, cognate receptors have been reconstituted from multiple parasitic nematodes that are found to vary in subunit composition. In order to understand the implications of receptor composition change and the origins of potentially novel drug targets, we investigated a specific example of subunit duplication based on analysis of genome data for 25 species from the 50 helminth genome initiative. We found multiple independent duplications of the unc-29, acetylcholine receptor subunit, where codon substitution rate analysis identified positive, directional selection acting on amino acid positions associated with subunit assembly. Characterization of four gene copies from a model parasitic nematode, Haemonchus contortus, demonstrated that each copy has acquired unique functional characteristics based on phenotype rescue of transgenic C. elegans and electrophysiology of receptors reconstituted in Xenopus oocytes. We found evidence that a specific incompatibility has evolved for two subunits co-expressed in muscle. We demonstrated that functional divergence of acetylcholine receptors, driven by directional selection, can occur more rapidly than previously thought and may be mediated by alteration of receptor assembly. This phenomenon is common among the

Agricultural losses related to frost events: use of the 850 hPa level temperature as an explanatory variable of the damage cost

Science.gov (United States)

Papagiannaki, K.; Lagouvardos, K.; Kotroni, V.; Papagiannakis, G.

2014-09-01

The objective of this study is the analysis of damaging frost events in agriculture, by examining the relationship between the daily minimum temperature in the lower atmosphere (at an isobaric level of 850 hPa) and crop production losses. Furthermore, the study suggests a methodological approach for estimating agriculture risk due to frost events, with the aim of estimating the short-term probability and magnitude of frost-related financial losses for different levels of 850 hPa temperature. Compared with near-surface temperature forecasts, temperature forecasts at the level of 850 hPa are less influenced by varying weather conditions or by local topographical features; thus, they constitute a more consistent indicator of the forthcoming weather conditions. The analysis of the daily monetary compensations for insured crop losses caused by weather events in Greece shows that, during the period 1999-2011, frost caused more damage to crop production than any other meteorological phenomenon. Two regions of different geographical latitudes are examined further, to account for the differences in the temperature ranges developed within their ecological environment. Using a series of linear and logistic regressions, we found that minimum temperature (at an 850 hPa level), grouped into three categories according to its magnitude, and seasonality, are significant variables when trying to explain crop damage costs, as well as to predict and quantify the likelihood and magnitude of damaging frost events.

Expression and purification of functional human mu opioid receptor from E.coli.

Directory of Open Access Journals (Sweden)

Yanbin Ma

Full Text Available N-terminally his-tagged human mu opioid receptor, a G protein-coupled receptor was produced in E.coli employing synthetic codon-usage optimized constructs. The receptor was expressed in inclusion bodies and membrane-inserted in different E.coli strains. By optimizing the expression conditions the expression level for the membrane-integrated receptor was raised to 0.3-0.5 mg per liter of culture. Milligram quantities of receptor could be enriched by affinity chromatography from IPTG induced cultures grown at 18°C. By size exclusion chromatography the protein fraction with the fraction of alpha-helical secondary structure expected for a 7-TM receptor was isolated, by CD-spectroscopy an alpha-helical content of ca. 45% was found for protein solubilised in the detergent Fos-12. Receptor in Fos-12 micelles was shown to bind endomorphin-1 with a K(D of 61 nM. A final yield of 0.17 mg functional protein per liter of culture was obtained.

Elabela-apelin receptor signaling pathway is functional in mammalian systems.

Science.gov (United States)

Wang, Zhi; Yu, Daozhan; Wang, Mengqiao; Wang, Qilong; Kouznetsova, Jennifer; Yang, Rongze; Qian, Kun; Wu, Wenjun; Shuldiner, Alan; Sztalryd, Carole; Zou, Minghui; Zheng, Wei; Gong, Da-Wei

2015-02-02

Elabela (ELA) or Toddler is a recently discovered hormone which is required for normal development of heart and vasculature through activation of apelin receptor (APJ), a G protein-coupled receptor (GPCR), in zebrafish. The present study explores whether the ELA-APJ signaling pathway is functional in the mammalian system. Using reverse-transcription PCR, we found that ELA is restrictedly expressed in human pluripotent stem cells and adult kidney whereas APJ is more widely expressed. We next studied ELA-APJ signaling pathway in reconstituted mammalian cell systems. Addition of ELA to HEK293 cells over-expressing GFP-AJP fusion protein resulted in rapid internalization of the fusion receptor. In Chinese hamster ovarian (CHO) cells over-expressing human APJ, ELA suppresses cAMP production with EC50 of 11.1 nM, stimulates ERK1/2 phosphorylation with EC50 of 14.3 nM and weakly induces intracellular calcium mobilization. Finally, we tested ELA biological function in human umbilical vascular endothelial cells and showed that ELA induces angiogenesis and relaxes mouse aortic blood vessel in a dose-dependent manner through a mechanism different from apelin. Collectively, we demonstrate that the ELA-AJP signaling pathways are functional in mammalian systems, indicating that ELA likely serves as a hormone regulating the circulation system in adulthood as well as in embryonic development.

Intrapulmonary receptors in the Tegu lizard: II. Functional characteristics and localization;.

Science.gov (United States)

Scheid, P; Kuhlmann, W D; Fedde, M R

1977-02-01

Intrapulmonary receptors identified in the Tegu lizard by single-unit vagal recording (Fedde et al., 1977) were subjected to a number of stimuli and localized within the lung. Some carbon dioxide receptors could follow periodic changes in intrapulmonary CO2 concentrations as rapidly as 1.3 Hz; No oxygen sensitivity was observed with this receptor type, and halothane markedly depressed the discharge frequency. In response to intravenously injected acetazolamide they increased their discharge frequency and became almost totally insensitive to CO2, suggesting molecular per se is not the direct controller of receptor discharge; These receptors show many of the functional characteristics described for those in the avian lung. Afferent activity from both CO2 and mechanoreceptors could be elicited by electrically stimulating the lung surface. The CO2 receptors appeared to be organized in a receptive field covering more than 1 cm2 of lung surface, multiple receptors being innervated by a single afferent fiber. Activity in afferent fibers from mechanoreceptors could be evoked from only one distinct spot on the lung surface. Conduction velocities of afferent fibers from CO2 receptors ranged from 1 to 3 m-sec-1; from mechanoreceptors, from 1.9 to 5.2 m-sec-1.

Presence of Functional Neurotrophin TrkB Receptors in the Rat Superior Cervical Ganglion

Directory of Open Access Journals (Sweden)

Pablo Valle-Leija

2017-07-01

Full Text Available Sympathetic neurons express the neurotrophin receptors TrkA, p75NTR, and a non-functional truncated TrkB isoform (TrkB-Tc, but are not thought to express a functional full-length TrkB receptor (TrkB-Fl. We, and others, have demonstrated that nerve growth factor (NGF and brain derived neurotrophic factor (BDNF modulate synaptic transmission and synaptic plasticity in neurons of the superior cervical ganglion (SCG of the rat. To clarify whether TrkB is expressed in sympathetic ganglia and contributes to the effects of BDNF upon sympathetic function, we characterized the presence and activity of the neurotrophin receptors expressed in the adult SCG compared with their presence in neonatal and cultured sympathetic neurons. Here, we expand our previous study regarding the immunodetection of neurotrophin receptors. Immunohistochemical analysis revealed that 19% of adult ganglionic neurons expressed TrkB-Fl immunoreactivity (IR, 82% expressed TrkA-IR, and 51% expressed p75NTR-IR; TrkB-Tc would be expressed in 36% of neurons. In addition, using Western-blotting and reverse transcriptase polymerase chain reaction (RT-PCR analyses, we confirmed the expression of TrkB-Fl and TrkB-Tc protein and mRNA transcripts in adult SCG. Neonatal neurons expressed significantly more TrkA-IR and TrkB-Fl-IR than p75NTR-IR. Finally, the application of neurotrophin, and high frequency stimulation, induced the activation of Trk receptors and the downstream PI3-kinase (phosphatidyl inositol-3-kinase signaling pathway, thus evoking the phosphorylation of Trk and Akt. These results demonstrate that SCG neurons express functional TrkA and TrkB-Fl receptors, which may contribute to the differential modulation of synaptic transmission and long-term synaptic plasticity.

Presence of Functional Neurotrophin TrkB Receptors in the Rat Superior Cervical Ganglion.

Science.gov (United States)

Valle-Leija, Pablo; Cancino-Rodezno, Angeles; Sánchez-Tafolla, Berardo M; Arias, Erwin; Elinos, Diana; Feria, Jessica; Zetina, María E; Morales, Miguel A; Cifuentes, Fredy

2017-01-01

Sympathetic neurons express the neurotrophin receptors TrkA, p75NTR, and a non-functional truncated TrkB isoform (TrkB-Tc), but are not thought to express a functional full-length TrkB receptor (TrkB-Fl). We, and others, have demonstrated that nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) modulate synaptic transmission and synaptic plasticity in neurons of the superior cervical ganglion (SCG) of the rat. To clarify whether TrkB is expressed in sympathetic ganglia and contributes to the effects of BDNF upon sympathetic function, we characterized the presence and activity of the neurotrophin receptors expressed in the adult SCG compared with their presence in neonatal and cultured sympathetic neurons. Here, we expand our previous study regarding the immunodetection of neurotrophin receptors. Immunohistochemical analysis revealed that 19% of adult ganglionic neurons expressed TrkB-Fl immunoreactivity (IR), 82% expressed TrkA-IR, and 51% expressed p75NTR-IR; TrkB-Tc would be expressed in 36% of neurons. In addition, using Western-blotting and reverse transcriptase polymerase chain reaction (RT-PCR) analyses, we confirmed the expression of TrkB-Fl and TrkB-Tc protein and mRNA transcripts in adult SCG. Neonatal neurons expressed significantly more TrkA-IR and TrkB-Fl-IR than p75NTR-IR. Finally, the application of neurotrophin, and high frequency stimulation, induced the activation of Trk receptors and the downstream PI3-kinase (phosphatidyl inositol-3-kinase) signaling pathway, thus evoking the phosphorylation of Trk and Akt. These results demonstrate that SCG neurons express functional TrkA and TrkB-Fl receptors, which may contribute to the differential modulation of synaptic transmission and long-term synaptic plasticity.

Excess portal venous long-chain fatty acids induce syndrome X via HPA axis and sympathetic activation

NARCIS (Netherlands)

Benthem, L; Keizer, Klaas-Jan; Wiegman, CH; De Boer, SF; Strubbe, JH; Steffens, AB; Kuipers, F; Scheurink, AJW

2000-01-01

We tested the hypothesis that excessive portal venous supply of long-chain fatty acids to the liver contributes to the development of insulin resistance via activation of the hypothalamus-pituitary-adrenal axis (HPA axis) and sympathetic system. Rats received an intraportal infusion of the

The relation between hypothalamic-pituitary-adrenal (HPA) axis activity and age of onset of alcohol use

NARCIS (Netherlands)

Evans, B.E.; Greaves-Lord, K.; Euser, A.S.; Franken, I.H.A.; Huizink, A.C.

2012-01-01

Aims: Hypothalamic-pituitary-adrenal (HPA) axis activity may prove a viable biomarker for identifying those susceptible to alcohol use disorders. The purpose of this study was to examine the relation of the age at which adolescents begin drinking with diurnal and stress cortisol. Design:

PTP1B regulates Eph receptor function and trafficking

OpenAIRE

Nievergall, Eva; Janes, Peter W.; Stegmayer, Carolin; Vail, Mary E.; Haj, Fawaz G.; Teng, Shyh Wei; Neel, Benjamin G.; Bastiaens, Philippe I.; Lackmann, Martin

2010-01-01

Eph receptors orchestrate cell positioning during normal and oncogenic development. Their function is spatially and temporally controlled by protein tyrosine phosphatases (PTPs), but the underlying mechanisms are unclear and the identity of most regulatory PTPs are unknown. We demonstrate here that PTP1B governs signaling and biological activity of EphA3. Changes in PTP1B expression significantly affect duration and amplitude of EphA3 phosphorylation and biological function, whereas confocal ...

Design and Synthesis of Benzimidazoles As Novel Corticotropin-Releasing Factor 1 Receptor Antagonists.

Science.gov (United States)

Mochizuki, Michiyo; Kori, Masakuni; Kobayashi, Katsumi; Yano, Takahiko; Sako, Yuu; Tanaka, Maiko; Kanzaki, Naoyuki; Gyorkos, Albert C; Corrette, Christopher P; Cho, Suk Young; Pratt, Scott A; Aso, Kazuyoshi

2016-03-24

Benzazole derivatives with a flexible aryl group bonded through a one-atom linker as a new scaffold for a corticotropin-releasing factor 1 (CRF1) receptor antagonist were designed, synthesized, and evaluated. We expected that structural diversity could be expanded beyond that of reported CRF1 receptor antagonists. In a structure-activity relationship study, 4-chloro-N(2)-(4-chloro-2-methoxy-6-methylphenyl)-1-methyl-N(7),N(7)-dipropyl-1H-benzimidazole-2,7-diamine 29g had the most potent binding activity against a human CRF1 receptor and the antagonistic activity (IC50 = 9.5 and 88 nM, respectively) without concerns regarding cytotoxicity at 30 μM. Potent CRF1 receptor-binding activity in brain in an ex vivo test and suppression of stress-induced activation of the hypothalamus-pituitary-adrenocortical (HPA) axis were also observed at 138 μmol/kg of compound 29g after oral administration in mice. Thus, the newly designed benzimidazole 29g showed in vivo CRF1 receptor antagonistic activity and good brain penetration, indicating that it is a promising lead for CRF1 receptor antagonist drug discovery research.

5α-Bile alcohols function as farnesoid X receptor antagonists

International Nuclear Information System (INIS)

Nishimaki-Mogami, Tomoko; Kawahara, Yosuke; Tamehiro, Norimasa; Yoshida, Takemi; Inoue, Kazuhide; Ohno, Yasuo; Nagao, Taku; Une, Mizuho

2006-01-01

The farnesoid X receptor (FXR) is a bile acid/alcohol-activated nuclear receptor that regulates lipid homeostasis. Unlike other steroid receptors, FXR binds bile acids in an orientation that allows the steroid nucleus A to face helix 12 in the receptor, a crucial domain for coactivator-recruitment. Because most naturally occurring bile acids and alcohols contain a cis-oriented A, which is distinct from that of other steroids and cholesterol metabolites, we investigated the role of this 5β-configuration in FXR activation. The results showed that the 5β-(A/B cis) bile alcohols 5β-cyprinol and bufol are potent FXR agonists, whereas their 5α-(A/B trans) counterparts antagonize FXR transactivation and target gene expression. Both isomers bound to FXR, but their ability to induce coactivator-recruitment and thereby induce transactivation differed. These findings suggest a critical role for the A orientation of bile salts in agonist/antagonist function

Designer lipid-like peptides: a class of detergents for studying functional olfactory receptors using commercial cell-free systems.

Science.gov (United States)

Corin, Karolina; Baaske, Philipp; Ravel, Deepali B; Song, Junyao; Brown, Emily; Wang, Xiaoqiang; Wienken, Christoph J; Jerabek-Willemsen, Moran; Duhr, Stefan; Luo, Yuan; Braun, Dieter; Zhang, Shuguang

2011-01-01

A crucial bottleneck in membrane protein studies, particularly G-protein coupled receptors, is the notorious difficulty of finding an optimal detergent that can solubilize them and maintain their stability and function. Here we report rapid production of 12 unique mammalian olfactory receptors using short designer lipid-like peptides as detergents. The peptides were able to solubilize and stabilize each receptor. Circular dichroism showed that the purified olfactory receptors had alpha-helical secondary structures. Microscale thermophoresis suggested that the receptors were functional and bound their odorants. Blot intensity measurements indicated that milligram quantities of each olfactory receptor could be produced with at least one peptide detergent. The peptide detergents' capability was comparable to that of the detergent Brij-35. The ability of 10 peptide detergents to functionally solubilize 12 olfactory receptors demonstrates their usefulness as a new class of detergents for olfactory receptors, and possibly other G-protein coupled receptors and membrane proteins.

Designer lipid-like peptides: a class of detergents for studying functional olfactory receptors using commercial cell-free systems.

Directory of Open Access Journals (Sweden)

Karolina Corin

Full Text Available A crucial bottleneck in membrane protein studies, particularly G-protein coupled receptors, is the notorious difficulty of finding an optimal detergent that can solubilize them and maintain their stability and function. Here we report rapid production of 12 unique mammalian olfactory receptors using short designer lipid-like peptides as detergents. The peptides were able to solubilize and stabilize each receptor. Circular dichroism showed that the purified olfactory receptors had alpha-helical secondary structures. Microscale thermophoresis suggested that the receptors were functional and bound their odorants. Blot intensity measurements indicated that milligram quantities of each olfactory receptor could be produced with at least one peptide detergent. The peptide detergents' capability was comparable to that of the detergent Brij-35. The ability of 10 peptide detergents to functionally solubilize 12 olfactory receptors demonstrates their usefulness as a new class of detergents for olfactory receptors, and possibly other G-protein coupled receptors and membrane proteins.

Functionality of the Paracoccidioides mating α-pheromone-receptor system.

Directory of Open Access Journals (Sweden)

Jéssica A Gomes-Rezende

Full Text Available Recent evidence suggests that Paracoccidioides species have the potential to undergo sexual reproduction, although no sexual cycle has been identified either in nature or under laboratory conditions. In the present work we detected low expression levels of the heterothallic MAT loci genes MAT1-1 and MAT1-2, the α-pheromone (PBα gene, and the α- and a-pheromone receptor (PREB and PREA genes in yeast and mycelia forms of several Paracoccidioides isolates. None of the genes were expressed in a mating type dependent manner. Stimulation of P. brasiliensis MAT1-2 strains with the synthetic α-pheromone peptide failed to elicit transcriptional activation of MAT1-2, PREB or STE12, suggesting that the strains tested are insensitive to α-pheromone. In order to further evaluate the biological functionality of the pair α-pheromone and its receptor, we took advantage of the heterologous expression of these Paracoccidioides genes in the corresponding S. cerevisiae null mutants. We show that S. cerevisiae strains heterologously expressing PREB respond to Pbα pheromone either isolated from Paracoccidioides culture supernatants or in its synthetic form, both by shmoo formation and by growth and cell cycle arrests. This allowed us to conclude that Paracoccidioides species secrete an active α-pheromone into the culture medium that is able to activate its cognate receptor. Moreover, expression of PREB or PBα in the corresponding null mutants of S. cerevisiae restored mating in these non-fertile strains. Taken together, our data demonstrate pheromone signaling activation by the Paracoccidioides α-pheromone through its receptor in this yeast model, which provides novel evidence for the existence of a functional mating signaling system in Paracoccidioides.

Mechanisms underlying the comorbidity between depressive and addictive disorders in adolescents: interactions between stress and HPA activity.

Science.gov (United States)

Rao, Uma; Hammen, Constance L; Poland, Russell E

2009-03-01

Depression may be a precursor to substance use disorder in some youngsters, and substance abuse might complicate the subsequent course of depression. This study examined whether hypothalamic-pituitary-adrenal (HPA) activity and stressful life experiences are related to the development of substance use disorder in depressed and nondepressed adolescents, and whether substance use disorder predicts a worsening course of depression. Urinary-free cortisol was measured for 3 nights in 151 adolescents with no prior history of substance use disorder (55 depressed, 48 at high risk for depression, and 48 normal subjects). Information was obtained on recent stressful life experiences. The participants were followed for up to 5 years to assess the onset of substance use disorder, course of depression, and stressful experiences. The relationships among depression, cortisol as a measure of HPA activity, stressful experiences, and substance use disorder were examined. Elevated cortisol was associated with onset of substance use disorder. Stressful life experiences moderated this relationship. Cortisol and stress accounted for the effects of a history or risk of depression on the development of substance use disorder. Substance use disorder was associated with higher frequency of subsequent depressive episodes. Higher cortisol prior to the onset of substance use disorder may indicate vulnerability to substance use disorder. Stressful experiences increase the risk for substance use disorder in such vulnerable youth. The high prevalence of substance use disorders in depressed individuals may be explained, in part, by high levels of stress and increased HPA activity.

Muscarinic acetylcholine receptor subtypes: localization and structure/function

DEFF Research Database (Denmark)

Brann, M R; Ellis, J; Jørgensen, H

1993-01-01

Based on the sequence of the five cloned muscarinic receptor subtypes (m1-m5), subtype selective antibody and cDNA probes have been prepared. Use of these probes has demonstrated that each of the five subtypes has a markedly distinct distribution within the brain and among peripheral tissues...... are described, as well as the implied structures of these functional domains....

Analysis and compensation for the joint effects of HPA nonlinearity, I/Q imbalance and crosstalk in MIMO beamforming systems

KAUST Repository

Qi, Jian

2011-03-01

In this paper, we investigate the joint effects of high-power amplifier (HPA) nonlinearity, in-phase/quadrature-phase (I/Q) imbalance and crosstalk, on the performance of multiple-input multiple-output (MIMO) transmit beamforming (TB) systems, and propose a compensation method for the three impairments together. The performance of the MIMO TB system equipped with the proposed compensation scheme is evaluated in terms of average symbol error probability and capacity when transmissions are performed over uncorrelated Rayleigh fading channels. Numerical results are provided and show the effects on performance of several system parameters, namely, the HPA parameters, image-leakage ratio, crosstalk, numbers of antennas, length of pilot symbols and phase-shift keying modulation order. © 2011 IEEE.

Selective androgen receptor modulators as function promoting therapies.

Science.gov (United States)

Bhasin, Shalender; Jasuja, Ravi

2009-05-01

The past decade has witnessed an unprecedented discovery effort to develop selective androgen receptor modulators (SARMs) that improve physical function and bone health without adversely affecting the prostate and cardiovascular outcomes. This review describes the historical evolution, the rationale for SARM development, and the mechanisms of testosterone action and SARM selectivity. Although steroidal SARMs have been around since the 1940s, a number of nonsteroidal SARMs that do not serve as substrates for CYP19 aromatase or 5alpha-reductase, act as full agonists in muscle and bone and as partial agonists in prostate are in development. The differing interactions of steroidal and nonsteroidal compounds with androgen receptor (AR) contribute to their unique pharmacologic actions. Ligand binding induces specific conformational changes in the ligand-binding domain, which could modulate surface topology and protein-protein interactions between AR and coregulators, resulting in tissue-specific gene regulation. Preclinical studies have demonstrated the ability of SARMs to increase muscle and bone mass in preclinical rodent models with varying degree of prostate sparing. Phase I trials of SARMs in humans have reported modest increments in fat-free mass. SARMs hold promise as a new class of function promoting anabolic therapies for a number of clinical indications, including functional limitations associated with aging and chronic disease, frailty, cancer cachexia, and osteoporosis.

Activation of ATP-sensitive potassium channel by iptakalim normalizes stress-induced HPA axis disorder and depressive behaviour by alleviating inflammation and oxidative stress in mouse hypothalamus.

Science.gov (United States)

Zhao, Xiao-Jie; Zhao, Zhan; Yang, Dan-Dan; Cao, Lu-Lu; Zhang, Ling; Ji, Juan; Gu, Jun; Huang, Ji-Ye; Sun, Xiu-Lan

2017-04-01

Stress-induced disturbance of the hypothalamic-pituitary-adrenal (HPA) axis is strongly implicated in incidence of mood disorders. A heightened neuroinflammatory response and oxidative stress play a fundamental role in the dysfunction of the HPA axis. We have previously demonstrated that iptakalim (Ipt), a new ATP-sensitive potassium (K-ATP) channel opener, could prevent oxidative injury and neuroinflammation against multiple stimuli-induced brain injury. The present study was to demonstrate the impacts of Ipt in stress-induced HPA axis disorder and depressive behavior. We employed 2 stress paradigms: 8 weeks of continuous restraint stress (chronic restraint stress, CRS) and 2h of restraint stress (acute restraint stress, ARS), to mimic both chronic stress and severe acute stress. Prolonged (4 weeks) and short-term (a single injection) Ipt treatment was administered 30min before each stress paradigm. We found that HPA axis was altered after stress, with different responses to CRS (lower ACTH and CORT, higher AVP, but normal CRH) and ARS (higher CRH, ACTH and CORT, but normal AVP). Both prolonged and short-term Ipt treatment normalized stress-induced HPA axis disorders and abnormal behaviors in mice. CRS and ARS up-regulated mRNA levels of inflammation-related molecules (TNFα, IL-1β, IL-6 and TLR4) and oxidative stress molecules (gp91phox, iNOS and Nrf2) in the mouse hypothalamus. Double immunofluorescence showed CRS and ARS increased microglia activation (CD11b and TNFα) and oxidative stress in neurons (NeuN and gp91phox), which were alleviated by Ipt. Therefore, the present study reveals that Ipt could prevent against stress-induced HPA axis disorders and depressive behavior by alleviating inflammation and oxidative stress in the hypothalamus. Copyright © 2017 Elsevier Inc. All rights reserved.

Attenuated stress response to acute restraint and forced swimming stress in arginine vasopressin 1b receptor subtype (Avpr1b) receptor knockout mice and wild-type mice treated with a novel Avpr1b receptor antagonist.

Science.gov (United States)

Roper, J A; Craighead, M; O'Carroll, A-M; Lolait, S J

2010-11-01

Arginine vasopressin (AVP) synthesised in the parvocellular region of the hypothalamic paraventricular nucleus and released into the pituitary portal vessels acts on the 1b receptor subtype (Avpr1b) present in anterior pituitary corticotrophs to modulate the release of adrenocorticotrophic hormone (ACTH). Corticotrophin-releasing hormone is considered the major drive behind ACTH release; however, its action is augmented synergistically by AVP. To determine the extent of vasopressinergic influence in the hypothalamic-pituitary-adrenal axis response to restraint and forced swimming stress, we compared the stress hormone levels [plasma ACTH in both stressors and corticosterone (CORT) in restraint stress only] following acute stress in mutant Avpr1b knockout (KO) mice compared to their wild-type controls following the administration of a novel Avpr1b antagonist. Restraint and forced swimming stress-induced increases in plasma ACTH were significantly diminished in mice lacking a functional Avpr1b and in wild-type mice that had been pre-treated with Avpr1b antagonist. A corresponding decrease in plasma CORT levels was also observed in acute restraint-stressed knockout male mice, and in Avpr1b-antagonist-treated male wild-type mice. By contrast, plasma CORT levels were not reduced in acutely restraint-stressed female knockout animals, or in female wild-type animals pre-treated with Avpr1b antagonist. These results demonstrate that pharmacological antagonism or inactivation of Avpr1b causes a reduction in the hypothalamic-pituitary-adrenal (HPA) axis response, particularly ACTH, to acute restraint and forced swimming stress, and show that Avpr1b knockout mice constitute a model by which to study the contribution of Avpr1b to the HPA axis response to acute stressors. © 2010 The Authors. Journal of Neuroendocrinology © 2010 Blackwell Publishing Ltd.

Positive and negative social support and HPA-axis hyperactivity: Evidence from glucocorticoids in human hair.

Science.gov (United States)

Iob, Eleonora; Kirschbaum, Clemens; Steptoe, Andrew

2018-06-12

While positive social support is associated with lower prevalence of disease and better treatment outcomes, negative social relationships can instead have unfavourable consequences for several physical and mental health conditions. However, the specific mechanisms by which this nexus might operate remain poorly understood. Hypothalamic-pituitary-adrenal (HPA) axis hyperactivity owing to psychosocial stress has been proposed as a potential pathway underlying the link between social support and health. Hair glucocorticoids such as cortisol and cortisone are emerging as promising biomarkers of long-term retrospective HPA activation. Therefore, the aim of this investigation was to examine the effects of positive and negative experiences of social support within key relationships (i.e. spouse/partner, children, other family members, and friends) on cortisol and cortisone. These associations were tested in a sample of 2520 older adults (mean age 68.1) from the English Longitudinal Study of Ageing. Hair samples were collected in wave 6 (2012/13). To understand the impact of cumulative exposure to poor social support, the analysis used self-reported data from waves 4 (2008/09) and 6. Covariates included demographic, socioeconomic, lifestyle, and hair characteristics. In cross sectional analyses, lower positive support from all sources and specifically from children were associated with higher cortisol. Additionally, lower positive support from children was positively associated with cortisone. Similarly, higher overall negative support was related to higher cortisol, and greater negative support from children was also positively associated with cortisone. In longitudinal analyses, there was evidence for positive associations between hair glucocorticoids and cumulative exposure to poorer social support. Experiences of low positive and high negative social support, particularly from children, were both related to higher hair glucocorticoids. Hence, social relationships of

The study of catalytic properties and phase composition of pyrolysis products of molybdophosphoric heteropolyacid. Communication 3. Environmental effect on the HPA pyrolysis

International Nuclear Information System (INIS)

Bondareva, V.M.; Andrushkevich, T.V.; Maksimovskaya, R.I.; Plyasova, L.M.; Litvak, G.S.; Burgina, E.B.

1997-01-01

Character of pyrolysis of molybdophosphonic heteropolyacid (HPA) (H 3 PMo 12 O 40 x13H 2 O) in different media (air, hydrogen, oxygen, helium, water vapour, as well reactive mixture containing acrolein) is studied within the temperature range of 200-700 deg C. With application of methods of X-ray analysis in situ, NMR 31 R and IR-spectroscopy it is shown that phase formation by HPA pyrolysis depends on the media, oxidation-reduction properties and availability of water vapour therein. 27 refs.; 5 figs

Isotopic rubidium ion efflux assay for the functional characterization of nicotinic acetylcholine receptors on clonal cell lines

International Nuclear Information System (INIS)

Lukas, R.J.; Cullen, M.J.

1988-01-01

An isotopic rubidium ion efflux assay has been developed for the functional characterization of nicotinic acetylcholine receptors on cultured neurons. This assay first involves the intracellular sequestration of isotopic potassium ion analog by the ouabain-sensitive action of a sodium-potassium ATPase. Subsequently, the release of isotopic rubidium ion through nicotinic acetylcholine receptor-coupled monovalent cation channels is activated by application of nicotinic agonists. Specificity of receptor-mediated efflux is demonstrated by its sensitivity to blockade by nicotinic, but not muscarinic, antagonists. The time course of agonist-mediated efflux, within the temporal limitations of the assay, indicates a slow inactivation of receptor function on prolonged exposure to agonist. Dose-response profiles (i) have characteristic shapes for different nicotinic agonists, (ii) are described by three operationally defined parameters, and (iii) reflect different affinities of agonists for binding sites that control receptor activation and functional inhibition. The rubidium ion efflux assay provides fewer hazards but greater sensitivity and resolution than isotopic sodium or rubidium ion influx assays for functional nicotinic receptors

Transceptors as a functional link of transporters and receptors

Directory of Open Access Journals (Sweden)

George Diallinas

2017-03-01

Full Text Available Cells need to communicate with their environment in order to obtain nutrients, grow, divide and respond to signals related to adaptation in changing physiological conditions or stress. A very basic question in biology is how cells, especially of those organisms living in rapidly changing habitats, sense their environment. Apparently, this question is of particular importance to all free-living microorganisms. The critical role of receptors, transporters and channels, transmembrane proteins located in the plasma membrane of all types of cells, in signaling environmental changes is well established. A relative newcomer in environment sensing are the so called transceptors, membrane proteins that possess both solute transport and receptor-like signaling activities. Now, the transceptor concept is further enlarged to include micronutrient sensing via the iron and zinc high-affinity transporters of Saccharomyces cerevisiae. Interestingly, what seems to underline the transport and/or sensing function of receptors, transporters and transceptors is ligand-induced conformational alterations recognized by downstream intracellular effectors.

Dissecting signaling and functions of adhesion G protein-coupled receptors

DEFF Research Database (Denmark)

Araç, Demet; Aust, Gabriela; Calebiro, Davide

2012-01-01

G protein-coupled receptors (GPCRs) comprise an expanded superfamily of receptors in the human genome. Adhesion class G protein-coupled receptors (adhesion-GPCRs) form the second largest class of GPCRs. Despite the abundance, size, molecular structure, and functions in facilitating cell and matrix...... contacts in a variety of organ systems, adhesion-GPCRs are by far the most poorly understood GPCR class. Adhesion-GPCRs possess a unique molecular structure, with extended N-termini containing various adhesion domains. In addition, many adhesion-GPCRs are autoproteolytically cleaved into an N......-terminal fragment (NTF, NT, α-subunit) and C-terminal fragment (CTF, CT, β-subunit) at a conserved GPCR autoproteolysis-inducing (GAIN) domain that contains a GPCR proteolysis site (GPS). These two features distinguish adhesion-GPCRs from other GPCR classes. Though active research on adhesion-GPCRs in diverse areas...

Functional characterization of bursicon receptor and genome-wide analysis for identification of genes affected by bursicon receptor RNAi

Science.gov (United States)

Bai, Hua; Palli, Subba R.

2010-01-01

Bursicon is an insect neuropeptide hormone that is secreted from the central nervous system into the hemolymph and initiates cuticle tanning. The receptor for bursicon is encoded by the rickets (rk) gene and belongs to the G protein-coupled receptor (GPCR) superfamily. The bursicon and its receptor regulate cuticle tanning as well as wing expansion after adult eclosion. However, the molecular action of bursicon signaling remains unclear. We utilized RNA interference (RNAi) and microarray to study the function of the bursicon receptor (Tcrk) in the model insect, Tribolium castaneum. The data included here showed that in addition to cuticle tanning and wing expansion reported previously, Tcrk is also required for development and expansion of integumentary structures and adult eclosion. Using custom microarrays, we identified 24 genes that are differentially expressed between Tcrk RNAi and control insects. Knockdown in the expression of one of these genes, TC004091, resulted in the arrest of adult eclosion. Identification of genes that are involved in bursicon receptor mediated biological processes will provide tools for future studies on mechanisms of bursicon action. PMID:20457145

Synthesis and SAR studies of novel 2-(6-aminomethylaryl-2-aryl-4-oxo-quinazolin-3(4H)-yl)acetamide vasopressin V1b receptor antagonists.

Science.gov (United States)

Napier, Susan E; Letourneau, Jeffrey J; Ansari, Nasrin; Auld, Douglas S; Baker, James; Best, Stuart; Campbell-Wan, Leigh; Chan, Ray; Craighead, Mark; Desai, Hema; Ho, Koc-Kan; MacSweeney, Cliona; Milne, Rachel; Richard Morphy, J; Neagu, Irina; Ohlmeyer, Michael H J; Pick, Jack; Presland, Jeremy; Riviello, Chris; Zanetakos, Heather A; Zhao, Jiuqiao; Webb, Maria L

2011-06-15

Synthesis and structure-activity relationships (SAR) of a novel series of vasopressin V(1b) antagonists are described. 2-(6-Aminomethylaryl-2-aryl-4-oxo-quinazolin-3(4H)-yl)acetamide have been identified with low nanomolar affinity for the V(1b) receptor and good selectivity with respect to related receptors V(1a), V(2) and OT. Optimised compound 16 shows a good pharmacokinetic profile and activity in a mechanistic model of HPA dysfunction. Copyright © 2011 Elsevier Ltd. All rights reserved.

The CRF Family of Neuropeptides and their Receptors - Mediators of the Central Stress Response

Science.gov (United States)

Dedic, Nina; Chen, Alon; Deussing, Jan M.

2018-01-01

Background: Dysregulated stress neurocircuits, caused by genetic and/or environmental changes, underlie the development of many neuropsychiatric disorders. Corticotropin-releasing factor (CRF) is the major physiological activator of the hypothalamic-pituitary-adrenal (HPA) axis and conse-quently a primary regulator of the mammalian stress response. Together with its three family members, urocortins (UCNs) 1, 2, and 3, CRF integrates the neuroendocrine, autonomic, metabolic and behavioral responses to stress by activating its cognate receptors CRFR1 and CRFR2. Objective: Here we review the past and current state of the CRF/CRFR field, ranging from pharmacologi-cal studies to genetic mouse models and virus-mediated manipulations. Results: Although it is well established that CRF/CRFR1 signaling mediates aversive responses, includ-ing anxiety and depression-like behaviors, a number of recent studies have challenged this viewpoint by revealing anxiolytic and appetitive properties of specific CRF/CRFR1 circuits. In contrast, the UCN/CRFR2 system is less well understood and may possibly also exert divergent functions on physiol-ogy and behavior depending on the brain region, underlying circuit, and/or experienced stress conditions. Conclusion: A plethora of available genetic tools, including conventional and conditional mouse mutants targeting CRF system components, has greatly advanced our understanding about the endogenous mecha-nisms underlying HPA system regulation and CRF/UCN-related neuronal circuits involved in stress-related behaviors. Yet, the detailed pathways and molecular mechanisms by which the CRF/UCN-system translates negative or positive stimuli into the final, integrated biological response are not completely un-derstood. The utilization of future complementary methodologies, such as cell-type specific Cre-driver lines, viral and optogenetic tools will help to further dissect the function of genetically defined CRF/UCN neurocircuits in the context of

Acetylation of pregnane X receptor protein determines selective function independent of ligand activation

International Nuclear Information System (INIS)

Biswas, Arunima; Pasquel, Danielle; Tyagi, Rakesh Kumar; Mani, Sridhar

2011-01-01

Research highlights: → Pregnane X receptor (PXR), a major regulatory protein, is modified by acetylation. → PXR undergoes dynamic deacetylation upon ligand-mediated activation. → SIRT1 partially mediates PXR deacetylation. → PXR deacetylation per se induces lipogenesis mimicking ligand-mediated activation. -- Abstract: Pregnane X receptor (PXR), like other members of its class of nuclear receptors, undergoes post-translational modification [PTM] (e.g., phosphorylation). However, it is unknown if acetylation (a major and common form of protein PTM) is observed on PXR and, if it is, whether it is of functional consequence. PXR has recently emerged as an important regulatory protein with multiple ligand-dependent functions. In the present work we show that PXR is indeed acetylated in vivo. SIRT1 (Sirtuin 1), a NAD-dependent class III histone deacetylase and a member of the sirtuin family of proteins, partially mediates deacetylation of PXR. Most importantly, the acetylation status of PXR regulates its selective function independent of ligand activation.

EPO-independent functional EPO receptor in breast cancer enhances estrogen receptor activity and promotes cell proliferation

International Nuclear Information System (INIS)

Reinbothe, Susann; Larsson, Anna-Maria; Vaapil, Marica; Wigerup, Caroline; Sun, Jianmin; Jögi, Annika; Neumann, Drorit; Rönnstrand, Lars; Påhlman, Sven

2014-01-01

Highlights: • New anti-human EPOR antibody confirms full-length EPOR expression in breast cancer cells. • Proliferation of breast cancer cells is not affected by rhEPO treatment in vitro. • EPOR knockdown impairs proliferation of ERa positive breast cancer cells. • EPOR knockdown reduces AKT phosphorylation and ERa activity. - Abstract: The main function of Erythropoietin (EPO) and its receptor (EPOR) is the stimulation of erythropoiesis. Recombinant human EPO (rhEPO) is therefore used to treat anemia in cancer patients. However, clinical trials have indicated that rhEPO treatment might promote tumor progression and has a negative effect on patient survival. In addition, EPOR expression has been detected in several cancer forms. Using a newly produced anti-EPOR antibody that reliably detects the full-length isoform of the EPOR we show that breast cancer tissue and cells express the EPOR protein. rhEPO stimulation of cultured EPOR expressing breast cancer cells did not result in increased proliferation, overt activation of EPOR (receptor phosphorylation) or a consistent activation of canonical EPOR signaling pathway mediators such as JAK2, STAT3, STAT5, or AKT. However, EPOR knockdown experiments suggested functional EPO receptors in estrogen receptor positive (ERα + ) breast cancer cells, as reduced EPOR expression resulted in decreased proliferation. This effect on proliferation was not seen in ERα negative cells. EPOR knockdown decreased ERα activity further supports a mechanism by which EPOR affects proliferation via ERα-mediated mechanisms. We show that EPOR protein is expressed in breast cancer cells, where it appears to promote proliferation by an EPO-independent mechanism in ERα expressing breast cancer cells

EPO-independent functional EPO receptor in breast cancer enhances estrogen receptor activity and promotes cell proliferation

Energy Technology Data Exchange (ETDEWEB)

Reinbothe, Susann; Larsson, Anna-Maria; Vaapil, Marica; Wigerup, Caroline [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); CREATE Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel); Sun, Jianmin [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); Jögi, Annika [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); CREATE Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel); Neumann, Drorit [Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel); Rönnstrand, Lars [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); Påhlman, Sven, E-mail: sven.pahlman@med.lu.se [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); CREATE Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel)

2014-02-28

Highlights: • New anti-human EPOR antibody confirms full-length EPOR expression in breast cancer cells. • Proliferation of breast cancer cells is not affected by rhEPO treatment in vitro. • EPOR knockdown impairs proliferation of ERa positive breast cancer cells. • EPOR knockdown reduces AKT phosphorylation and ERa activity. - Abstract: The main function of Erythropoietin (EPO) and its receptor (EPOR) is the stimulation of erythropoiesis. Recombinant human EPO (rhEPO) is therefore used to treat anemia in cancer patients. However, clinical trials have indicated that rhEPO treatment might promote tumor progression and has a negative effect on patient survival. In addition, EPOR expression has been detected in several cancer forms. Using a newly produced anti-EPOR antibody that reliably detects the full-length isoform of the EPOR we show that breast cancer tissue and cells express the EPOR protein. rhEPO stimulation of cultured EPOR expressing breast cancer cells did not result in increased proliferation, overt activation of EPOR (receptor phosphorylation) or a consistent activation of canonical EPOR signaling pathway mediators such as JAK2, STAT3, STAT5, or AKT. However, EPOR knockdown experiments suggested functional EPO receptors in estrogen receptor positive (ERα{sup +}) breast cancer cells, as reduced EPOR expression resulted in decreased proliferation. This effect on proliferation was not seen in ERα negative cells. EPOR knockdown decreased ERα activity further supports a mechanism by which EPOR affects proliferation via ERα-mediated mechanisms. We show that EPOR protein is expressed in breast cancer cells, where it appears to promote proliferation by an EPO-independent mechanism in ERα expressing breast cancer cells.

Role of post-translational modifications on structure, function and pharmacology of class C G protein-coupled receptors

DEFF Research Database (Denmark)

Nørskov-Lauritsen, Lenea; Bräuner-Osborne, Hans

2015-01-01

taste receptors (T1R1-3), one calcium-sensing (CaS) receptor, one GPCR, class C, group 6, subtype A (GPRC6) receptor, and seven orphan receptors. G protein-coupled receptors undergo a number of post-translational modifications, which regulate their structure, function and/or pharmacology. Here, we...

IL-4 function can be transferred to the IL-2 receptor by tyrosine containing sequences found in the IL-4 receptor alpha chain.

Science.gov (United States)

Wang, H Y; Paul, W E; Keegan, A D

1996-02-01

IL-4 binds to a cell surface receptor complex that consists of the IL-4 binding protein (IL-4R alpha) and the gamma chain of the IL-2 receptor complex (gamma c). The receptors for IL-4 and IL-2 have several features in common; both use the gamma c as a receptor component, and both activate the Janus kinases JAK-1 and JAK-3. In spite of these similarities, IL-4 evokes specific responses, including the tyrosine phosphorylation of 4PS/IRS-2 and the induction of CD23. To determine whether sequences within the cytoplasmic domain of the IL-4R alpha specify these IL-4-specific responses, we transplanted the insulin IL-4 receptor motif (I4R motif) of the huIL-4R alpha to the cytoplasmic domain of a truncated IL-2R beta. In addition, we transplanted a region that contains peptide sequences shown to block Stat6 binding to DNA. We analyzed the ability of cells expressing these IL-2R-IL-4R chimeric constructs to respond to IL-2. We found that IL-4 function could be transplanted to the IL-2 receptor by these regions and that proliferative and differentiative functions can be induced by different receptor sequences.

Sheep oocyte expresses leptin and functional leptin receptor mRNA

Directory of Open Access Journals (Sweden)

Seyyed Jalil Taheri

2016-09-01

Conclusions: The result of present study reveals that leptin and its functional receptor (Ob-Rb mRNA are expressed in sheep oocyte and further studies should investigate the role(s of leptin on sheep oocyte physiology and embryo development.

Blockade of cannabinoid CB receptor function protects against in vivo disseminating brain damage following NMDA-induced excitotoxicity

DEFF Research Database (Denmark)

Hansen, H.H.; Ramos, J.A.; Fernández-Ruiz, J.

2002-01-01

-induced excitotoxic damage in the ipsilateral forebrain was not influenced by agonist-stimulated CB receptor function. In contrast, blockade of CB, but not CB, receptor activity evoked a robust neuroprotective response by reducing the infarct area and the number of cortical degenerating neurons. These results suggest...... receptor function on NMDA-induced excitotoxicity. Neonatal (6-day-old) rat pups received a systemic injection of a mixed CB/CB receptor agonist (WIN55,212-2) or their respective antagonists (SR141716A for CB and SR144528 for CB) prior to an unilateral intrastriatal microinjection of NMDA. The NMDA...... a critical involvement of CB receptor tonus on neuronal survival following NMDA receptor-induced excitotoxicity in vivo....

Mapping the human corticotropin releasing hormone binding protein gene (CRHBP) to the long arm of chromosome 5 (5q11.2-q13.3)

Energy Technology Data Exchange (ETDEWEB)

Vamvakopoulos, N.C. [Univ. of Thessaly School of Medicine, Larisa (Greece); Sioutopoulou, T.O. [Univ. of Athens Medical School (Greece); Durkin, S.A. [American Type Culture Collection, Rockville, MD (United States)

1995-01-01

Unexpected stimulation or stress activates the heat shock protein (hsp) system at the cellular level and the hypothalamic-pituitary-adrenal (HPA) axis at the level of the whole organism. At the molecular level, these two systems communicate through the functional interaction between hsp90 and glucocorticoid receptor (GR). The corticotropin releasing hormone (CRH) system regulates the mammalian stress response by coordinating the activity of the HPA axis. It consists of the 41-amino-acid-long principal hypothalamic secretagogue for pituitary adrenocorticotropic hormone (ACTH), CRH, its receptor (CRHR), and its binding protein (CRHBP). Because of its central role in the coordination of stress response and whole body homeostasis, the CRH system has been implicated in the pathogenesis of neuroendocrine and psychiatric disease. 19 refs., 1 fig.

Membrane-mediated oligomerization of G protein coupled receptors and its implications for GPCR function

Directory of Open Access Journals (Sweden)

Stefan Gahbauer

2016-10-01

Full Text Available The dimerization or even oligomerization of G protein coupled receptors (GPCRs causes ongoing, controversial debates about its functional role and the coupled biophysical, biochemical or biomedical implications. A continously growing number of studies hints to a relation between oligomerization and function of GPCRs and strengthens the assumption that receptor assembly plays a key role in the regulation of protein function. Additionally, progress in the structural analysis of GPCR-G protein and GPCR-ligand interactions allows to distinguish between actively functional and non-signalling complexes. Recent findings further suggest that the surrounding membrane, i.e. its lipid composition may modulate the preferred dimerization interface and as a result the abundance of distinct dimeric conformations. In this review, the association of GPCRs and the role of the membrane in oligomerization will be discussed. An overview of the different reported oligomeric interfaces is provided and their capability for signaling discussed. The currently available data is summarized with regard to the formation of GPCR oligomers, their structures and dependency on the membrane microenvironment as well as the coupling of oligomerization to receptor function.

Honey Bee Allatostatins Target Galanin/Somatostatin-Like Receptors and Modulate Learning: A Conserved Function?

Directory of Open Access Journals (Sweden)

Elodie Urlacher

Full Text Available Sequencing of the honeybee genome revealed many neuropeptides and putative neuropeptide receptors, yet functional characterization of these peptidic systems is scarce. In this study, we focus on allatostatins, which were first identified as inhibitors of juvenile hormone synthesis, but whose role in the adult honey bee (Apis mellifera brain remains to be determined. We characterize the bee allatostatin system, represented by two families: allatostatin A (Apime-ASTA and its receptor (Apime-ASTA-R; and C-type allatostatins (Apime-ASTC and Apime-ASTCC and their common receptor (Apime-ASTC-R. Apime-ASTA-R and Apime-ASTC-R are the receptors in bees most closely related to vertebrate galanin and somatostatin receptors, respectively. We examine the functional properties of the two honeybee receptors and show that they are transcriptionally expressed in the adult brain, including in brain centers known to be important for learning and memory processes. Thus we investigated the effects of exogenously applied allatostatins on appetitive olfactory learning in the bee. Our results show that allatostatins modulate learning in this insect, and provide important insights into the evolution of somatostatin/allatostatin signaling.

HPA axis response to psychological stress and treatment retention in residential substance abuse treatment: a prospective study.

Science.gov (United States)

Daughters, Stacey B; Richards, Jessica M; Gorka, Stephanie M; Sinha, Rajita

2009-12-01

Substance abuse treatment programs are often characterized by high rates of premature treatment dropout, which increases the likelihood of relapse to drug use. Negative reinforcement models of addiction emphasize an individual's inability to tolerate stress as a key factor for understanding poor substance use treatment outcomes, and evidence indicates that dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis contributes to an individual's inability to respond adaptively to stress. The aim of the current study was to examine whether HPA axis response to stress is predictive of treatment retention among a sample of drug users in residential substance abuse treatment. Prospective study assessing treatment retention among 102 individuals enrolled in residential substance abuse treatment. Participants completed two computerized stress tasks, and HPA axis response to stress was measured via salivary cortisol at five time points from baseline (pre-stress) to 30 min post-stress exposure. The main outcome measures were treatment dropout (categorical) and total number of days in treatment (continuous). A significantly higher salivary cortisol response to stress was observed in treatment dropouts compared to treatment completers. Further, Cox proportional hazards survival analyses indicated that a higher peak cortisol response to stress was associated with a shorter number of days to treatment dropout. Results indicate that a higher salivary cortisol level in response to stress is associated with an inability to remain in substance abuse treatment. These findings are the first to document a biological marker of stress as a predictor of substance abuse treatment dropout, and support the development and implementation of treatments targeting this vulnerability.

Defensive and pathological functions of the gastrointestinal NK3 receptor.

Science.gov (United States)

Sanger, Gareth J; Tuladhar, Bishwa R; Bueno, Lionel; Furness, John B

2006-10-01

In general, normal gut functions are unaffected by selective NK(3) receptor antagonists such as talnetant (SB-223412), osanetant (SR 142901) or SB-235375. However, NK(3) receptors may mediate certain defensive or pathological intestinal processes. The precise mechanisms, by which this role is achieved, are not fully understood. In summary, intense stimulation of the intrinsic primary afferent neurones (IPANs) of the enteric nervous system is thought to release tachykinins from these neurones, to induce slow excitation (slow EPSPs) of connecting IPANs. This is hypothesised to cause hypersensitivity and disrupt intestinal motility, at least partly explaining why NK(3) receptor antagonism can reduce the level of disruption caused by supramaximal distension pressures in vitro. Tachykinin release from IPANs may also increase C-fibre sensitivity, directly or indirectly. Thus, NK(3) receptor antagonists can inhibit nociception associated with intestinal distension, in normal animals or after pre-sensitisation by restraint stress. Importantly, such inhibition has been found with SB-235375, a peripherally restricted antagonist. SB-235375 can also reduce a visceromotor response to brief colorectal distension without affecting similar responses to skin pinch, providing additional evidence for intestinal-specific activity. NK(3) receptor biology is, therefore, revealing a novel pathway by which disruptions in intestinal motility and nociception can be induced.

Hsp70 cochaperones HspBP1 and BAG-1M differentially regulate steroid hormone receptor function.

Directory of Open Access Journals (Sweden)

Regina T Knapp

Full Text Available Hsp70 binding protein 1 (HspBP1 and Bcl2-associated athanogene 1 (BAG-1, the functional orthologous nucleotide exchange factors of the heat shock protein 70 kilodalton (Hsc70/Hsp70 chaperones, catalyze the release of ADP from Hsp70 while inducing different conformational changes of the ATPase domain of Hsp70. An appropriate exchange rate of ADP/ATP is crucial for chaperone-dependent protein folding processes. Among Hsp70 client proteins are steroid receptors such as the glucocorticoid receptor (GR, the mineralocorticoid receptor (MR, and the androgen receptor (AR. BAG-1 diversely affects steroid receptor activity, while to date the influence of HspBP1 on steroid receptor function is mostly unknown. Here, we compared the influence of HspBP1 and BAG-1M on Hsp70-mediated steroid receptor folding complexes and steroid receptor activity. Coimmunoprecipitation studies indicated preferential binding of Hsp40 and the steroid receptors to BAG-1M as compared to HspBP1. Furthermore, Hsp70 binding to the ligand-binding domain of GR was reduced in the presence of HspBP1 but not in the presence of BAG-1M as shown by pull-down assays. Reporter gene experiments revealed an inhibitory effect on GR, MR, and AR at a wide range of HspBP1 protein levels and at hormone concentrations at or approaching saturation. BAG-1M exhibited a transition from stimulatory effects at low BAG-1M levels to inhibitory effects at higher BAG-1M levels. Overall, BAG-1M and HspBP1 had differential impacts on the dynamic composition of steroid receptor folding complexes and on receptor function with important implications for steroid receptor physiology.

Epigenetic modification of the oxytocin and glucocorticoid receptor genes is linked to attachment avoidance in young adults.

Science.gov (United States)

Ein-Dor, Tsachi; Verbeke, Willem J M I; Mokry, Michal; Vrtička, Pascal

2018-08-01

Attachment in the context of intimate pair bonds is most frequently studied in terms of the universal strategy to draw near, or away, from significant others at moments of personal distress. However, important interindividual differences in the quality of attachment exist, usually captured through secure versus insecure - anxious and/or avoidant - attachment orientations. Since Bowlby's pioneering writings on the theory of attachment, it has been assumed that attachment orientations are influenced by both genetic and social factors - what we would today describe and measure as gene by environment interaction mediated by epigenetic DNA modification - but research in humans on this topic remains extremely limited. We for the first time examined relations between intra-individual differences in attachment and epigenetic modification of the oxytocin receptor (OXTR) and glucocorticoid receptor (NR3C1) gene promoter in 109 young adult human participants. Our results revealed that attachment avoidance was significantly and specifically associated with increased OXTR and NR3C1 promoter methylation. These findings offer first tentative clues on the possible etiology of attachment avoidance in humans by showing epigenetic modification in genes related to both social stress regulation and HPA axis functioning.

Activation of Brain Somatostatin Signaling Suppresses CRF Receptor-Mediated Stress Response

Directory of Open Access Journals (Sweden)

Andreas Stengel

2017-04-01

Full Text Available Corticotropin-releasing factor (CRF is the hallmark brain peptide triggering the response to stress and mediates—in addition to the stimulation of the hypothalamus-pituitary-adrenal (HPA axis—other hormonal, behavioral, autonomic and visceral components. Earlier reports indicate that somatostatin-28 injected intracerebroventricularly counteracts the acute stress-induced ACTH and catecholamine release. Mounting evidence now supports that activation of brain somatostatin signaling exerts a broader anti-stress effect by blunting the endocrine, autonomic, behavioral (with a focus on food intake and visceral gastrointestinal motor responses through the involvement of distinct somatostatin receptor subtypes.

Functional characterization and evolution of PTH/PTHrP receptors: insights from the chicken

Directory of Open Access Journals (Sweden)

Pinheiro Pedro LC

2012-07-01

Full Text Available Abstract Background The parathyroid hormone (PTH-family consists of a group of structurally related factors that regulate calcium and bone homeostasis and are also involved in development of organs such as the heart, mammary gland and immune system. They interact with specific members of family 2 B1 G-protein coupled receptors (GPCRs, which have been characterised in teleosts and mammals. Two PTH/PTHrP receptors, PTH1R and PTH2R exist in mammals and in teleost fish a further receptor PTH3R has also been identified. Recently in chicken, PTH-family members involved in calcium transport were characterized and specific PTHRs are suggested to exist although they have not yet been isolated or functionally characterized. The aim of this study is to further explore the evolution and function of the vertebrate PTH/PTHrP system through the isolation, phylogenetic analysis and functional characterization of the chicken receptors. Results Two PTHRs were isolated in chicken and sequence comparison and phylogenetic analysis indicate that the chicken receptors correspond to PTH1R and PTH3R, which emerged prior to the teleost/tetrapod divergence since they are present in cartilaginous fish. The vertebrate PTH2R receptor and its ligand TIP39 have been lost from bird genomes. Chicken PTH1R and PTH3R have a divergent and widespread tissue expression and are also evident in very early embryonic stages of development. Receptor stimulation studies using HEK293 cells stably expressing the chicken PTH1R and PTH3R and monitoring cAMP production revealed they are activated by chicken 1–34 N-terminal PTH-family peptides in a dose dependent manner. PTH-L and PTHrP were the most effective peptides in activating PTH1R (EC50 = 7.7 nM and EC50 = 22.7 nM, respectively. In contrast, PTH-L (100 nM produced a small cAMP accumulation on activation of PTH3R but PTHrP and PTH (EC50 = 2.5 nM and EC50 = 22.1 nM, respectively readily activated the receptor. PTHr

The structure and function of glutamate receptors: Mg2+ block to X-ray diffraction.

Science.gov (United States)

Mayer, Mark L

2017-01-01

Experiments on the action of glutamate on mammalian and amphibian nervous systems started back in the 1950s but decades passed before it became widely accepted that glutamate was the major excitatory neurotransmitter in the CNS. The pace of research greatly accelerated in the 1980s when selective ligands that identified glutamate receptor subtypes became widely available, and voltage clamp techniques, coupled with rapid perfusion, began to resolve the unique functional properties of what cloning subsequently revealed to be a large family of receptors with numerous subtypes. More recently the power of X-ray crystallography and cryo-EM has been applied to the study of glutamate receptors, revealing their atomic structures, and the conformational changes that underlie their gating. In this review I summarize the history of this field, viewed through the lens of a career in which I spent 3 decades working on the structure and function of glutamate receptor ion channels. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'. Published by Elsevier Ltd.

Expression and Purification of Functional Ligand-binding Domains of T1R3 Taste Receptors

Energy Technology Data Exchange (ETDEWEB)

Nie,Y.; Hobbs, J.; Vigues, S.; Olson, W.; Conn, G.; Munger, S.

2006-01-01

Chemosensory receptors, including odor, taste, and vomeronasal receptors, comprise the largest group of G protein-coupled receptors (GPCRs) in the mammalian genome. However, little is known about the molecular determinants that are critical for the detection and discrimination of ligands by most of these receptors. This dearth of understanding is due in part to difficulties in preparing functional receptors suitable for biochemical and biophysical analyses. Here we describe in detail two strategies for the expression and purification of the ligand-binding domain of T1R taste receptors, which are constituents of the sweet and umami taste receptors. These class C GPCRs contain a large extracellular N-terminal domain (NTD) that is the site of interaction with most ligands and that is amenable to expression as a separate polypeptide in heterologous cells. The NTD of mouse T1R3 was expressed as two distinct fusion proteins in Escherichia coli and purified by column chromatography. Spectroscopic analysis of the purified NTD proteins shows them to be properly folded and capable of binding ligands. This methodology should not only facilitate the characterization of T1R ligand interactions but may also be useful for dissecting the function of other class C GPCRs such as the large family of orphan V2R vomeronasal receptors.

Evidence for functional pre-coupled complexes of receptor heteromers and adenylyl cyclase.

Science.gov (United States)

Navarro, Gemma; Cordomí, Arnau; Casadó-Anguera, Verónica; Moreno, Estefanía; Cai, Ning-Sheng; Cortés, Antoni; Canela, Enric I; Dessauer, Carmen W; Casadó, Vicent; Pardo, Leonardo; Lluís, Carme; Ferré, Sergi

2018-03-28

G protein-coupled receptors (GPCRs), G proteins and adenylyl cyclase (AC) comprise one of the most studied transmembrane cell signaling pathways. However, it is unknown whether the ligand-dependent interactions between these signaling molecules are based on random collisions or the rearrangement of pre-coupled elements in a macromolecular complex. Furthermore, it remains controversial whether a GPCR homodimer coupled to a single heterotrimeric G protein constitutes a common functional unit. Using a peptide-based approach, we here report evidence for the existence of functional pre-coupled complexes of heteromers of adenosine A 2A receptor and dopamine D 2 receptor homodimers coupled to their cognate Gs and Gi proteins and to subtype 5 AC. We also demonstrate that this macromolecular complex provides the necessary frame for the canonical Gs-Gi interactions at the AC level, sustaining the ability of a Gi-coupled GPCR to counteract AC activation mediated by a Gs-coupled GPCR.

A dynamic view of molecular switch behavior at serotonin receptors: implications for functional selectivity.

Directory of Open Access Journals (Sweden)

Maria Martí-Solano

Full Text Available Functional selectivity is a property of G protein-coupled receptors that allows them to preferentially couple to particular signaling partners upon binding of biased agonists. Publication of the X-ray crystal structure of serotonergic 5-HT1B and 5-HT2B receptors in complex with ergotamine, a drug capable of activating G protein coupling and β-arrestin signaling at the 5-HT1B receptor but clearly favoring β-arrestin over G protein coupling at the 5-HT2B subtype, has recently provided structural insight into this phenomenon. In particular, these structures highlight the importance of specific residues, also called micro-switches, for differential receptor activation. In our work, we apply classical molecular dynamics simulations and enhanced sampling approaches to analyze the behavior of these micro-switches and their impact on the stabilization of particular receptor conformational states. Our analysis shows that differences in the conformational freedom of helix 6 between both receptors could explain their different G protein-coupling capacity. In particular, as compared to the 5-HT1B receptor, helix 6 movement in the 5-HT2B receptor can be constrained by two different mechanisms. On the one hand, an anchoring effect of ergotamine, which shows an increased capacity to interact with the extracellular part of helices 5 and 6 and stabilize them, hinders activation of a hydrophobic connector region at the center of the receptor. On the other hand, this connector region in an inactive conformation is further stabilized by unconserved contacts extending to the intracellular part of the 5-HT2B receptor, which hamper opening of the G protein binding site. This work highlights the importance of considering receptor capacity to adopt different conformational states from a dynamic perspective in order to underpin the structural basis of functional selectivity.

A Novel Tenebrio molitor Cadherin Is a Functional Receptor for Bacillus thuringiensis Cry3Aa Toxin*

OpenAIRE

Fabrick, Jeff; Oppert, Cris; Lorenzen, Marcé D.; Morris, Kaley; Oppert, Brenda; Jurat-Fuentes, Juan Luis

2009-01-01

Cry toxins produced by the bacterium Bacillus thuringiensis are effective biological insecticides. Cadherin-like proteins have been reported as functional Cry1A toxin receptors in Lepidoptera. Here we present data that demonstrate that a coleopteran cadherin is a functional Cry3Aa toxin receptor. The Cry3Aa receptor cadherin was cloned from Tenebrio molitor larval midgut mRNA, and the predicted protein, TmCad1, has domain structure and a putative toxin binding region similar to those in lepid...

Antioxidant Functions of the Aryl Hydrocarbon Receptor

Directory of Open Access Journals (Sweden)

Cornelia Dietrich

2016-01-01

Full Text Available The aryl hydrocarbon receptor (AhR is a transcription factor belonging to the basic helix-loop-helix/PER-ARNT-SIM family. It is activated by a variety of ligands, such as environmental contaminants like polycyclic aromatic hydrocarbons or dioxins, but also by naturally occurring compounds and endogenous ligands. Binding of the ligand leads to dimerization of the AhR with aryl hydrocarbon receptor nuclear translocator (ARNT and transcriptional activation of several xenobiotic phase I and phase II metabolizing enzymes. It is generally accepted that the toxic responses of polycyclic aromatic hydrocarbons, dioxins, and structurally related compounds are mediated by activation of the AhR. A multitude of studies indicate that the AhR operates beyond xenobiotic metabolism and exerts pleiotropic functions. Increasing evidence points to a protective role of the AhR against carcinogenesis and oxidative stress. Herein, I will highlight data demonstrating a causal role of the AhR in the antioxidant response and present novel findings on potential AhR-mediated antioxidative mechanisms.

Estrogen receptor β and oxytocin interact to modulate anxiety-like behavior and neuroendocrine stress reactivity in adult male and female rats.

Science.gov (United States)

Kudwa, Andrea E; McGivern, Robert F; Handa, Robert J

2014-04-22

The hypothalamic-pituitary-adrenal (HPA) axis is activated in response to stressors and is controlled by neurons residing in the paraventricular nucleus of the hypothalamus (PVN). Although gonadal steroid hormones can influence HPA reactivity to stressors, the exact mechanism of action is not fully understood. It is known, however, that estrogen receptor β (ERβ) inhibits HPA reactivity and decreases anxiety-like behavior in rodents. Since ERβ is co-expressed with oxytocin (OT) in neurons of the PVN, an ERβ-selective agonist was utilized to test the whether ERβ decreases stress-induced HPA reactivity and anxiety-like behaviors via an OTergic pathway. Adult gonadectomized male and female rats were administered diarylpropionitrile, or vehicle, peripherally for 5days. When tested for anxiety-like behavior on the elevated plus maze (EPM), diarylpropionitrile-treated males and females significantly increased time on the open arm of the EPM compared to vehicle controls indicating that ERβ reduces anxiety-like behaviors. One week after behavioral evaluation, rats were subjected to a 20minute restraint stress. Treatment with diarylpropionitrile reduced CORT and ACTH responses in both males and females. Subsequently, another group of animals was implanted with cannulae directed at the lateral ventricle. One week later, rats underwent the same protocol as above but with the additional treatment of intracerebroventricular infusion with an OT antagonist (des Gly-NH2 d(CH2)5 [Tyr(Me)(2), Thr(4)] OVT) or VEH, 20min prior to behavioral evaluation. OT antagonist treatment blocked the effects of diarylpropionitrile on the display of anxiety-like behaviors and plasma CORT levels. These data indicate that ERβ and OT interact to modulate the HPA reactivity and the display of anxiety-like behaviors. Copyright © 2014 Elsevier Inc. All rights reserved.

Functional pharmacology of cloned heterodimeric GABA-B receptors expressed in mammalian cells

DEFF Research Database (Denmark)

Bräuner-Osborne, Hans; Krogsgaard-Larsen, P

1999-01-01

reported in different tissues, and this study thus provides a functional assay of cloned GABAB receptors which should be a valuable tool for further characterization of GABAB ligands. Finally, we can conclude that the functional pharmacological profiles of the two GABABR1 splice variants are very similar....

The selection of stopping power and mass energy absorption coefficient data for the HPA Code of Practice for dosimetry

International Nuclear Information System (INIS)

Williams, P.C.

1985-01-01

The author draws attention to a discussion by Cunningham and Schultz (1984) which states that, 'with the exception of the NACP and AAPM protocols, the selection of stopping power and energy absorption coefficient ratios has been based upon only the stated accelerating potential of the accelerator', and points out that the HPA Revised Code of Practice should be added to these exceptions. In calculating the HPA's new Csub(lambda) values, a similar, but not identical, approach was taken in order to determine the stopping power and absorption coefficient ratios at each radiation quality. It was recognised that the approximation of a spectrum to a monoenergetic spectrum of between 0.4 and 0.45 of the maximum energy, as had been done in calculating the values, given in ICRU Report 14, was incorrect. (U.K.)

Structural analysis of binding functionality of folic acid-PEG dendrimers against folate receptor.

Science.gov (United States)

Sampogna-Mireles, Diana; Araya-Durán, Ingrid D; Márquez-Miranda, Valeria; Valencia-Gallegos, Jesús A; González-Nilo, Fernando D

2017-03-01

Dendrimers functionalized with folic acid (FA) are drug delivery systems that can selectively target cancer cells with folate receptors (FR-α) overexpression. Incorporation of polyethylene glycol (PEG) can enhance dendrimers solubility and pharmacokinetics, but ligand-receptor binding must not be affected. In this work we characterized, at atomic level, the binding functionality of conventional site-specific dendrimers conjugated with FA with PEG 750 or PEG 3350 as a linker. After Molecular Dynamics simulation, we observed that both PEG's did not interfere over ligand-receptor binding functionality. Although binding kinetics could be notably affected, the folate fragment from both dendrimers remained exposed to the solvent before approaching selectively to FR-α. PEG 3350 provided better solubility and protection from enzymatic degradation to the dendrimer than PEG 750. Also, FA-PEG3350 dendrimer showed a slightly better interaction with FR-α than FA-PEG750 dendrimer. Therefore, theoretical evidence supports that both dendrimers are suitable as drug delivery systems for cancer therapies. Copyright © 2017 Elsevier Inc. All rights reserved.

Modulation of the Hypothalamic-Pituitary-Adrenal Axis by Early Life Stress Exposure

Science.gov (United States)

van Bodegom, Miranda; Homberg, Judith R.; Henckens, Marloes J. A. G.

2017-01-01

-axis hyper-reactivity in adulthood, as also found in major depression. This hyper-activity is related to increased corticotrophin-releasing hormone signaling and impaired glucocorticoid receptor-mediated negative feedback. In contrast, initial evidence for HPA-axis hypo-reactivity is observed for early social deprivation, potentially reflecting the abnormal HPA-axis function as observed in post-traumatic stress disorder, and future studies should investigate its neural/neuroendocrine foundation in further detail. Interestingly, experiencing additional (chronic) stress in adulthood seems to normalize these alterations in HPA-axis function, supporting the match/mismatch theory. PMID:28469557

Functional Analysis of the Tomato Immune Receptor Ve1 through Domain Swaps with Its Non-Functional Homolog Ve2

Science.gov (United States)

Rovenich, Hanna; Song, Yin; Liebrand, Thomas W. H.; Masini, Laura; van den Berg, Grardy C. M.; Joosten, Matthieu H. A. J.; Thomma, Bart P. H. J.

2014-01-01

Resistance in tomato against race 1 strains of the fungal vascular wilt pathogens Verticillium dahliae and V. albo-atrum is mediated by the Ve locus. This locus comprises two closely linked inversely oriented genes, Ve1 and Ve2, which encode cell surface receptors of the extracellular leucine-rich repeat receptor-like protein (eLRR-RLP) type. While Ve1 mediates Verticillium resistance through monitoring the presence of the recently identified V. dahliae Ave1 effector, no functionality for Ve2 has been demonstrated in tomato. Ve1 and Ve2 contain 37 eLRRs and share 84% amino acid identity, facilitating investigation of Ve protein functionality through domain swapping. In this study it is shown that Ve chimeras in which the first thirty eLRRs of Ve1 were replaced by those of Ve2 remain able to induce HR and activate Verticillium resistance, and that deletion of these thirty eLRRs from Ve1 resulted in loss of functionality. Also the region between eLRR30 and eLRR35 is required for Ve1-mediated resistance, and cannot be replaced by the region between eLRR30 and eLRR35 of Ve2. We furthermore show that the cytoplasmic tail of Ve1 is required for functionality, as truncation of this tail results in loss of functionality. Moreover, the C-terminus of Ve2 fails to activate immune signaling as chimeras containing the C-terminus of Ve2 do not provide Verticillium resistance. Furthermore, Ve1 was found to interact through its C-terminus with the eLRR-containing receptor-like kinase (eLRR-RLK) interactor SOBIR1 that was recently identified as an interactor of eLRR-RLP (immune) receptors. Intriguingly, also Ve2 was found to interact with SOBIR1. PMID:24505431

Functional Characterization of a Novel Class of Morantel-Sensitive Acetylcholine Receptors in Nematodes.

Directory of Open Access Journals (Sweden)

Elise Courtot

2015-12-01

Full Text Available Acetylcholine receptors are pentameric ligand-gated channels involved in excitatory neuro-transmission in both vertebrates and invertebrates. In nematodes, they represent major targets for cholinergic agonist or antagonist anthelmintic drugs. Despite the large diversity of acetylcholine-receptor subunit genes present in nematodes, only a few receptor subtypes have been characterized so far. Interestingly, parasitic nematodes affecting human or animal health possess two closely related members of this gene family, acr-26 and acr-27 that are essentially absent in free-living or plant parasitic species. Using the pathogenic parasitic nematode of ruminants, Haemonchus contortus, as a model, we found that Hco-ACR-26 and Hco-ACR-27 are co-expressed in body muscle cells. We demonstrated that co-expression of Hco-ACR-26 and Hco-ACR-27 in Xenopus laevis oocytes led to the functional expression of an acetylcholine-receptor highly sensitive to the anthelmintics morantel and pyrantel. Importantly we also reported that ACR-26 and ACR-27, from the distantly related parasitic nematode of horses, Parascaris equorum, also formed a functional acetylcholine-receptor highly sensitive to these two drugs. In Caenorhabditis elegans, a free-living model nematode, we demonstrated that heterologous expression of the H. contortus and P. equorum receptors drastically increased its sensitivity to morantel and pyrantel, mirroring the pharmacological properties observed in Xenopus oocytes. Our results are the first to describe significant molecular determinants of a novel class of nematode body wall muscle AChR.

Functional Characterization of a Novel Class of Morantel-Sensitive Acetylcholine Receptors in Nematodes

Science.gov (United States)

Courtot, Elise; Charvet, Claude L.; Beech, Robin N.; Harmache, Abdallah; Wolstenholme, Adrian J.; Holden-Dye, Lindy; O’Connor, Vincent; Peineau, Nicolas; Woods, Debra J.; Neveu, Cedric

2015-01-01

Acetylcholine receptors are pentameric ligand–gated channels involved in excitatory neuro-transmission in both vertebrates and invertebrates. In nematodes, they represent major targets for cholinergic agonist or antagonist anthelmintic drugs. Despite the large diversity of acetylcholine-receptor subunit genes present in nematodes, only a few receptor subtypes have been characterized so far. Interestingly, parasitic nematodes affecting human or animal health possess two closely related members of this gene family, acr-26 and acr-27 that are essentially absent in free-living or plant parasitic species. Using the pathogenic parasitic nematode of ruminants, Haemonchus contortus, as a model, we found that Hco-ACR-26 and Hco-ACR-27 are co-expressed in body muscle cells. We demonstrated that co-expression of Hco-ACR-26 and Hco-ACR-27 in Xenopus laevis oocytes led to the functional expression of an acetylcholine-receptor highly sensitive to the anthelmintics morantel and pyrantel. Importantly we also reported that ACR-26 and ACR-27, from the distantly related parasitic nematode of horses, Parascaris equorum, also formed a functional acetylcholine-receptor highly sensitive to these two drugs. In Caenorhabditis elegans, a free-living model nematode, we demonstrated that heterologous expression of the H. contortus and P. equorum receptors drastically increased its sensitivity to morantel and pyrantel, mirroring the pharmacological properties observed in Xenopus oocytes. Our results are the first to describe significant molecular determinants of a novel class of nematode body wall muscle AChR. PMID:26625142

Cannabinoids and glucocorticoids modulate emotional memory after stress.

Science.gov (United States)

Akirav, Irit

2013-12-01

Bidirectional and functional relationships between glucocorticoids and the endocannabinoid system have been demonstrated. Here, I review the interaction between the endocannabinoid and glucocorticoid/stress systems. Specifically, stress is known to produce rapid changes in endocannabinoid signaling in stress-responsive brain regions. In turn, the endocannabinoid system plays an important role in the downregulation and habituation of hypothalamic-pituitary-adrenocortical (HPA) axis activity in response to stress. Glucocorticoids also recruit the endocannabinoid system to exert rapid negative feedback control of the HPA axis during stress. It became increasingly clear, however, that cannabinoid CB1 receptors are also abundantly expressed in the basolateral amygdala (BLA) and other limbic regions where they modulate emotional arousal effects on memory. Enhancing cannabinoids signaling using exogenous CB1 receptor agonists prevent the effects of acute stress on emotional memory. I propose a model suggesting that the ameliorating effects of exogenously administered cannabinoids on emotional learning after acute stress are mediated by the decrease in the activity of the HPA axis via GABAergic mechanisms in the amygdala. Copyright © 2013 Elsevier Ltd. All rights reserved.

Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells.

Science.gov (United States)

Bandoła, Joanna; Richter, Cornelia; Ryser, Martin; Jamal, Arshad; Ashton, Michelle P; von Bonin, Malte; Kuhn, Matthias; Dorschner, Benjamin; Alexopoulou, Dimitra; Navratiel, Katrin; Roeder, Ingo; Dahl, Andreas; Hedrich, Christian M; Bonifacio, Ezio; Brenner, Sebastian; Thieme, Sebastian

2017-01-01

Plasmacytoid dendritic cells (pDCs) regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR) by the antigen-presenting pDCs, mediated by toll-like receptor (TLR) 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders.

Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells

Directory of Open Access Journals (Sweden)

Joanna Bandoła

2017-08-01

Full Text Available Plasmacytoid dendritic cells (pDCs regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR by the antigen-presenting pDCs, mediated by toll-like receptor (TLR 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders.

Functional characteristics of the naked mole rat μ-opioid receptor.

Directory of Open Access Journals (Sweden)

Melanie Busch-Dienstfertig

Full Text Available While humans and most animals respond to µ-opioid receptor (MOR agonists with analgesia and decreased aggression, in the naked mole rat (NMR opioids induce hyperalgesia and severe aggression. Single nucleotide polymorphisms in the human mu-opioid receptor gene (OPRM1 can underlie altered behavioral responses to opioids. Therefore, we hypothesized that the primary structure of the NMR MOR may differ from other species. Sequencing of the NMR oprm1 revealed strong homology to other mammals, but exposed three unique amino acids that might affect receptor-ligand interactions. The NMR and rat oprm1 sequences were cloned into mammalian expression vectors and transfected into HEK293 cells. Radioligand binding and 3'-5'-cyclic adenosine monophosphate (cAMP enzyme immunoassays were used to compare opioid binding and opioid-mediated cAMP inhibition. At normalized opioid receptor protein levels we detected significantly lower [3H]DAMGO binding to NMR compared to rat MOR, but no significant difference in DAMGO-induced cAMP inhibition. Strong DAMGO-induced MOR internalization was detectable using radioligand binding and confocal imaging in HEK293 cells expressing rat or NMR receptor, while morphine showed weak or no effects. In summary, we found minor functional differences between rat and NMR MOR suggesting that other differences e.g. in anatomical distribution of MOR underlie the NMR's extreme reaction to opioids.

Functional characterisation of human glycine receptors in a fluorescence-based high throughput screening assay

DEFF Research Database (Denmark)

Jensen, Anders A.

2005-01-01

The human glycine receptor subtypes alpha1beta and alpha2 have been expressed stably in HEK293 cells, and the functional characteristics of the receptors have been characterised in the FLIPR Membrane Potential Assay. The pharmacological properties obtained for nine standard ligands at the two rec...

DMPD: Structure, function and regulation of the Toll/IL-1 receptor adaptor proteins. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 17667936 Structure, function and regulation of the Toll/IL-1 receptor adaptor prote... (.svg) (.html) (.csml) Show Structure, function and regulation of the Toll/IL-1 receptor adaptor proteins. ...PubmedID 17667936 Title Structure, function and regulation of the Toll/IL-1 recep

Analysis and compensation for the joint effects of HPA nonlinearity, I/Q imbalance and crosstalk in MIMO beamforming systems

KAUST Repository

Qi, Jian; Aissa, Sonia

2011-01-01

In this paper, we investigate the joint effects of high-power amplifier (HPA) nonlinearity, in-phase/quadrature-phase (I/Q) imbalance and crosstalk, on the performance of multiple-input multiple-output (MIMO) transmit beamforming (TB) systems

Function and distribution of 5-HT2 receptors in the honeybee (Apis mellifera.

Directory of Open Access Journals (Sweden)

Markus Thamm

Full Text Available BACKGROUND: Serotonin plays a pivotal role in regulating and modulating physiological and behavioral processes in both vertebrates and invertebrates. In the honeybee (Apis mellifera, serotonin has been implicated in division of labor, visual processing, and learning processes. Here, we present the cloning, heterologous expression, and detailed functional and pharmacological characterization of two honeybee 5-HT2 receptors. METHODS: Honeybee 5-HT2 receptor cDNAs were amplified from brain cDNA. Recombinant cell lines were established constitutively expressing receptor variants. Pharmacological properties of the receptors were investigated by Ca(2+ imaging experiments. Quantitative PCR was applied to explore the expression patterns of receptor mRNAs. RESULTS: The honeybee 5-HT2 receptor class consists of two subtypes, Am5-HT2α and Am5-HT2β. Each receptor gene also gives rise to alternatively spliced mRNAs that possibly code for truncated receptors. Only activation of the full-length receptors with serotonin caused an increase in the intracellular Ca(2+ concentration. The effect was mimicked by the agonists 5-methoxytryptamine and 8-OH-DPAT at low micromolar concentrations. Receptor activities were blocked by established 5-HT receptor antagonists such as clozapine, methiothepin, or mianserin. High transcript numbers were detected in exocrine glands suggesting that 5-HT2 receptors participate in secretory processes in the honeybee. CONCLUSIONS: This study marks the first molecular and pharmacological characterization of two 5-HT2 receptor subtypes in the same insect species. The results presented should facilitate further attempts to unravel central and peripheral effects of serotonin mediated by these receptors.

Function and distribution of 5-HT2 receptors in the honeybee (Apis mellifera).

Science.gov (United States)

Thamm, Markus; Rolke, Daniel; Jordan, Nadine; Balfanz, Sabine; Schiffer, Christian; Baumann, Arnd; Blenau, Wolfgang

2013-01-01

Serotonin plays a pivotal role in regulating and modulating physiological and behavioral processes in both vertebrates and invertebrates. In the honeybee (Apis mellifera), serotonin has been implicated in division of labor, visual processing, and learning processes. Here, we present the cloning, heterologous expression, and detailed functional and pharmacological characterization of two honeybee 5-HT2 receptors. Honeybee 5-HT2 receptor cDNAs were amplified from brain cDNA. Recombinant cell lines were established constitutively expressing receptor variants. Pharmacological properties of the receptors were investigated by Ca(2+) imaging experiments. Quantitative PCR was applied to explore the expression patterns of receptor mRNAs. The honeybee 5-HT2 receptor class consists of two subtypes, Am5-HT2α and Am5-HT2β. Each receptor gene also gives rise to alternatively spliced mRNAs that possibly code for truncated receptors. Only activation of the full-length receptors with serotonin caused an increase in the intracellular Ca(2+) concentration. The effect was mimicked by the agonists 5-methoxytryptamine and 8-OH-DPAT at low micromolar concentrations. Receptor activities were blocked by established 5-HT receptor antagonists such as clozapine, methiothepin, or mianserin. High transcript numbers were detected in exocrine glands suggesting that 5-HT2 receptors participate in secretory processes in the honeybee. This study marks the first molecular and pharmacological characterization of two 5-HT2 receptor subtypes in the same insect species. The results presented should facilitate further attempts to unravel central and peripheral effects of serotonin mediated by these receptors.

Aberrant dopamine D2-like receptor function in a rodent model of schizophrenia.

Science.gov (United States)

Perez, Stephanie M; Lodge, Daniel J

2012-11-01

Based on the observation that antipsychotic medications display antagonist properties at dopamine D2-like receptors, aberrant dopamine signaling has been proposed to underlie psychosis in patients with schizophrenia. Thus, it is not surprising that considerable research has been devoted to understanding the mechanisms involved in the antipsychotic action of these compounds. It is important to note that the majority of these studies have been performed in "normal" experimental animals. Given that these animals do not possess the aberrant neuronal information processing typically associated with schizophrenia, the aim of the current study was to examine the dopamine D2 receptor system in a rodent model of schizophrenia. Here, we demonstrate that methylazoxymethanol acetate (MAM)-treated rats display an enhanced effect of quinpirole on dopamine neuron activity and an aberrant locomotor response to D2-like receptor activation, suggesting changes in postsynaptic D2-like receptor function. To better understand the mechanisms underlying the enhanced response to D2-like ligands in MAM-treated rats, we examined the expression of D2, D3, and dopamine transporter mRNA in the nucleus accumbens and ventral tegmental area by quantitative reverse transcription-polymerase chain reaction. MAM-treated rats displayed a significant increase in dopamine D3 receptor mRNA expression in the nucleus accumbens with no significant changes in the expression of the D2 receptor. Taken together, these data demonstrate robust alterations in dopamine D2-like receptor function in a rodent model of schizophrenia and provide evidence that preclinical studies examining the mechanisms of antipsychotic drug action should be performed in animal models that mirror aspects of the abnormal neuronal transmission thought to underlie symptoms of schizophrenia.

The interaction of BDNF Val66Met, PTSD, and child abuse on psychophysiological reactivity and HPA axis function in a sample of Gulf War Veterans.

Science.gov (United States)

Young, Dmitri A; Neylan, Thomas C; O'Donovan, Aoife; Metzler, Thomas; Richards, Anne; Ross, Jessica A; Inslicht, Sabra S

2018-08-01

While the BDNF Val66Met polymorphism has been linked to various psychological disorders, limited focus has been on its relationship to posttraumatic stress disorder (PTSD) and early traumas such as child abuse. Therefore, we assessed whether Val66Met was associated with fear potentiated psychophysiological response and HPA axis dysfunction and whether PTSD status or child abuse history moderated these outcomes in a sample of Veterans. 226 and 173 participants engaged in a fear potentiated acoustic startle paradigm and a dexamethasone suppression test (DST) respectively. Fear conditions included no, ambiguous, and high threat conditions. Psychophysiological response measures included electromyogram (EMG), skin conductance response (SCR), and heart rate. The Clinician Administered PTSD Scale (CAPS) and the Trauma History Questionnaire (THQ) were used to assess PTSD status and child abuse history respectively. Met allele carriers exhibited greater SCR magnitudes in the no and ambiguous threat conditions (p < 0.01 and p < 0.05 respectively). Met carriers with PTSD exhibited greater physiological response magnitudes in the ambiguous (SCR, p < 0.001) and high threat conditions (SCR and heart rate, both p ≤ 0.005). Met carrier survivors of child abuse exhibited blunted heart rate magnitudes in the high threat condition (p < 0.01). Met allele carries with PTSD also exhibited greater percent cortisol suppression (p < 0.005). Limitations included small sample size and the cross-sectional nature of the data. The Val66met may impact PTSD susceptibility differentially via enhanced threat sensitivity and HPA axis dysregulation. Child abuse may moderate Val66Met's impact on threat reactivity. Future research should explore how neuronal mechanisms might mediate this risk. Published by Elsevier B.V.

Identification of the functional domains of ANT-1, a novel coactivator of the androgen receptor

International Nuclear Information System (INIS)

Fan Shuli; Goto, Kiminobu; Chen Guangchun; Morinaga, Hidetaka; Nomura, Masatoshi; Okabe, Taijiro; Nawata, Hajime; Yanase, Toshihiko

2006-01-01

Previously, we identified a transcriptional coactivator for the activation function-1 (AF-1) domain of the human androgen receptor (AR) and designated it androgen receptor N-terminal domain transactivating protein-1 (ANT-1). This coactivator, which contains multiple tetratricopeptide repeat (TPR) motifs from amino acid (aa) 294, is identical to a component of U5 small nuclear ribonucleoprotein particles and binds specifically to the AR or glucocorticoid receptor. Here, we identified four distinct functional domains. The AR-AF-1-binding domain, which bound to either aa 180-360 or 360-532 in AR-AF-1, clearly overlapped with TAU-1 and TAU-5. This domain and the subnuclear speckle formation domain in ANT-1 were assigned within the TPR motifs, while the transactivating and nuclear localization signal domains resided within the N-terminal sequence. The existence of these functional domains may further support the idea that ANT-1 can function as an AR-AF-1-specific coactivator while mediating a transcription-splicing coupling

Unique interaction pattern for a functionally biased ghrelin receptor agonist

DEFF Research Database (Denmark)

Sivertsen, Bjørn Behrens; Lang, Manja; Frimurer, Thomas M.

2011-01-01

Based on the conformationally constrained D-Trp-Phe-D-Trp (wFw) core of the prototype inverse agonist [D-Arg(1),D-Phe(5),D-Trp(7,9),Leu(11)]substance P, a series of novel, small, peptide-mimetic agonists for the ghrelin receptor were generated. By using various simple, ring-constrained spacers...... connecting the D-Trp-Phe-D-Trp motif with the important C-terminal carboxyamide group, 40 nm agonism potency was obtained and also in one case (wFw-Isn-NH(2), where Isn is isonipecotic acid) ~80% efficacy. However, in contrast to all previously reported ghrelin receptor agonists, the piperidine-constrained w......Fw-Isn-NH(2) was found to be a functionally biased agonist. Thus, wFw-Isn-NH(2) mediated potent and efficacious signaling through the Ga(q) and ERK1/2 signaling pathways, but in contrast to all previous ghrelin receptor agonists it did not signal through the serum response element, conceivably the Ga(12...

Socialização, acolhimento e integração organizacional no HPA Saúde :elaboração do manual de acolhimento do grupo HPA Saúde

OpenAIRE

Dias, Ana Sofia Martins

2016-01-01

Dissertação de mestrado, Gestão de Recursos Humanos, Escola Superior de Gestão, Hotelaria e Turismo, Universidade do Algarve, 2016 O presente relatório de estágio tem como tema principal a “ Socialização, Acolhimento e Integração Organizacional no HPA Saúde – Elaboração de um Manual de Acolhimento.” E surge como proposta no âmbito de estágio realizado no Hospital Particular de Alvor, sendo este detentor de várias unidades de saúde no Algarve. A realização do manual de acolhimen...

Overexpression of functional TrkA receptors after internalisation in human airway smooth muscle cells.

Science.gov (United States)

Freund-Michel, Véronique; Frossard, Nelly

2008-10-01

Trafficking of the TrkA receptor after stimulation by NGF is of emerging importance in structural cells in the context of airway inflammatory diseases. We have recently reported the expression of functional TrkA receptors in human airway smooth muscle cells (HASMC). We have here studied the TrkA trafficking mechanisms in these cells. TrkA disappearance from the cell membrane was induced within 5 min of NGF (3pM) stimulation. Co-immunoprecipitation of clathrin-TrkA was revealed, and TrkA internalisation inhibited either by clathrin inhibitors or by siRNA inducing downregulation of endogenous clathrin. TrkA internalised receptors were totally degraded in lysosomes, with no recycling phenomenon. Newly synthesized TrkA receptors were thereafter re-expressed at the cell membrane within 10 h. TrkA re-synthesis was inhibited by blockade of clathrin-dependent internalisation, but not of TrkA receptors lysosomal degradation. Finally, we observed that NGF multiple stimulations progressively increased TrkA expression in HASMC, which was associated with an increase in NGF/TrkA-dependent proliferation. In conclusion, we show here the occurrence of clathrin-dependent TrkA internalisation and lysosomal degradation in the airway smooth muscle, followed by upregulated re-synthesis of functional TrkA receptors and increased proliferative effect in the human airway smooth muscle. This may have pathophysiological consequences in airway inflammatory diseases.

A Novel Tenebrio molitor Cadherin Is a Functional Receptor for Bacillus thuringiensis Cry3Aa Toxin*

Science.gov (United States)

Fabrick, Jeff; Oppert, Cris; Lorenzen, Marcé D.; Morris, Kaley; Oppert, Brenda; Jurat-Fuentes, Juan Luis

2009-01-01

Cry toxins produced by the bacterium Bacillus thuringiensis are effective biological insecticides. Cadherin-like proteins have been reported as functional Cry1A toxin receptors in Lepidoptera. Here we present data that demonstrate that a coleopteran cadherin is a functional Cry3Aa toxin receptor. The Cry3Aa receptor cadherin was cloned from Tenebrio molitor larval midgut mRNA, and the predicted protein, TmCad1, has domain structure and a putative toxin binding region similar to those in lepidopteran cadherin B. thuringiensis receptors. A peptide containing the putative toxin binding region from TmCad1 bound specifically to Cry3Aa and promoted the formation of Cry3Aa toxin oligomers, proposed to be mediators of toxicity in lepidopterans. Injection of TmCad1-specific double-stranded RNA into T. molitor larvae resulted in knockdown of the TmCad1 transcript and conferred resistance to Cry3Aa toxicity. These data demonstrate the functional role of TmCad1 as a Cry3Aa receptor in T. molitor and reveal similarities between the mode of action of Cry toxins in Lepidoptera and Coleoptera. PMID:19416969

Os efeitos do estresse na função do eixo hipotalâmico-pituitário-adrenal em indivíduos com esquizofrenia The effects of stress on hypothalamic-pituitary-adrenal (HPA axis function in subjects with schizophrenia

Directory of Open Access Journals (Sweden)

Francesca L. Guest

2013-01-01

Full Text Available Nas últimas décadas, têm surgido evidências sugerindo que a patogênese de desordens psiquiátricas, tais como a esquizofrenia, pode envolver perturbações no eixo hipotalâmico-pituitário-adrenal (HPA. Variações na manifestação desses efeitos poderiam estar relacionadas a diferenças em sintomas clínicos entre os indivíduos afetados, assim como a diferenças na resposta ao tratamento. Tais efeitos podem também ser originados de complexas interações entre genes e fatores ambientais. Aqui, revisamos os efeitos do estresse maternal em anormalidades na regulação do eixo HPA e desenvolvimento de desordens psiquiátricas, incluindo a esquizofrenia. Estudos nessa área podem gerar o aumento do nosso entendimento da natureza multidimensional da esquizofrenia. Posterior pesquisa nesse campo poderia, em última instância, levar ao desenvolvimento de melhores diagnósticos e novas abordagens terapêuticas para essa debilitante condição psiquiátrica.Over the last few decades, evidence has been emerging that the pathogenesis of psychiatric disorders such as schizophrenia can involve perturbations of the hypothalamic-pituitary-adrenal (HPA axis. Variations in the manifestation of these effects could be related to the differences in clinical symptoms between affected individuals as well as to differences in treatment response. Such effects can also arise from the complex interaction between genes and environmental factors. Here, we review the effects of maternal stress on abnormalities in HPA axis regulation and the development of psychiatric disorders including schizophrenia. Studies in this area may prove critical for increasing our understanding of the multi-dimensional nature of schizophrenia. Further research in this area could ultimately lead to the development of improved diagnostics and novel therapeutic approaches for treating this debilitating psychiatric condition.

Functional importance of GLP-1 receptor species and expression levels in cell lines.

Science.gov (United States)

Knudsen, Lotte Bjerre; Hastrup, Sven; Underwood, Christina Rye; Wulff, Birgitte Schjellerup; Fleckner, Jan

2012-04-10

Of the mammalian species, only the GLP-1 receptors of rat and human origin have been described and characterized. Here, we report the cloning of the homologous GLP-1 receptors from mouse, rabbit, pig, cynomolgus monkey and chimp. The GLP-1 receptor is highly conserved across species, thus underlining the physiological importance of the peptide hormone and its receptor across a wide range of mammals. We expressed the receptors by stable transfection of BHK cells, both in cell lines with high expression levels of the cloned receptors, as well as in cell lines with lower expression levels, more comparable to endogenous expression of these receptors. High expression levels of cloned GLP-1 receptors markedly increased the potency of GLP-1 and other high affinity ligands, whereas the K(d) values were not affected. For a low affinity ligand like the ago-allosteric modulator Compound 2, expression levels of the human GLP-1 receptor were important for maximal efficacy as well as potency. The two natural metabolites of GLP-1, GLP-1(9-37) and GLP-1(9-36)amide were agonists when tested on a cell line with high expression of the recombinant human GLP-1 receptor, whereas they behaved as (low potent) antagonists on a cell line that expressed the receptor endogenously, as well as cells expressing a moderate level of the recombinant human GLP-1 receptor. The amide form was a more potent agonist than the free acid from. In conclusion, receptor expression level is an important parametre for selecting cell lines with cloned GLP-1 receptors for functional characterization of physiological and pharmaceutical ligands. Copyright © 2011 Elsevier B.V. All rights reserved.

Proteinase-Activated Receptor 1 (PAR1 regulates leukemic stem cell functions.

Directory of Open Access Journals (Sweden)

Nicole Bäumer

Full Text Available External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

Proteinase-Activated Receptor 1 (PAR1) regulates leukemic stem cell functions.

Science.gov (United States)

Bäumer, Nicole; Krause, Annika; Köhler, Gabriele; Lettermann, Stephanie; Evers, Georg; Hascher, Antje; Bäumer, Sebastian; Berdel, Wolfgang E; Müller-Tidow, Carsten; Tickenbrock, Lara

2014-01-01

External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

Megalin functions as an endocytic sonic hedgehog receptor.

Science.gov (United States)

McCarthy, Robert A; Barth, Jeremy L; Chintalapudi, Mastan R; Knaak, Christian; Argraves, W Scott

2002-07-12

Embryos deficient in the morphogen Sonic hedgehog (Shh) or the endocytic receptor megalin exhibit common neurodevelopmental abnormalities. Therefore, we have investigated the possibility that a functional relationship exists between the two proteins. During embryonic development, megalin was found to be expressed along the apical surfaces of neuroepithelial cells and was coexpressed with Shh in the ventral floor plate of the neural tube. Using enzyme-linked immunosorbent assay, homologous ligand displacement, and surface plasmon resonance techniques, it was found that the amino-terminal fragment of Shh (N-Shh) bound to megalin with high affinity. Megalin-expressing cells internalized N-Shh through a mechanism that was inhibited by antagonists of megalin, viz. anti-receptor-associated protein and anti-megalin antibodies. Heparin also inhibited N-Shh endocytosis, implicating proteoglycans in the internalization process, as has been described for other megalin ligands. Use of chloroquine to inhibit lysosomal proteinase activity showed that N-Shh endocytosed via megalin was not efficiently targeted to the lysosomes for degradation. The ability of megalin-internalized N-Shh to bypass lysosomes may relate to the finding that the interaction between N-Shh and megalin was resistant to dissociation with low pH. Together, these findings show that megalin is an efficient endocytic receptor for N-Shh. Furthermore, they implicate megalin as a new regulatory component of the Shh signaling pathway.

Functionally Selective AT(1) Receptor Activation Reduces Ischemia Reperfusion Injury

DEFF Research Database (Denmark)

Hostrup, Anders; Christensen, Gitte Lund; Bentzen, Bo Hjort

2012-01-01

of the physiological functions of AngII. The AT(1)R mediates its effects through both G protein-dependent and independent signaling, which can be separated by functionally selective agonists. In the present study we investigate the effect of AngII and the ß-arrestin biased agonist [SII]AngII on ischemia......]AngII had a protective effect. Together these results demonstrate a cardioprotective effect of simultaneous blockade of G protein signaling and activation of G protein independent signaling through AT(1 )receptors....

Amtyr1: characterization of a gene from honeybee (Apis mellifera) brain encoding a functional tyramine receptor.

Science.gov (United States)

Blenau, W; Balfanz, S; Baumann, A

2000-03-01

Biogenic amine receptors are involved in the regulation and modulation of various physiological and behavioral processes in both vertebrates and invertebrates. We have cloned a member of this gene family from the CNS of the honeybee, Apis mellifera. The deduced amino acid sequence is homologous to tyramine receptors cloned from Locusta migratoria and Drosophila melanogaster as well as to an octopamine receptor cloned from Heliothis virescens. Functional properties of the honeybee receptor were studied in stably transfected human embryonic kidney 293 cells. Tyramine reduced forskolin-induced cyclic AMP production in a dose-dependent manner with an EC50 of approximately 130 nM. A similar effect of tyramine was observed in membrane homogenates of honeybee brains. Octopamine also reduced cyclic AMP production in the transfected cell line but was both less potent (EC50 of approximately 3 microM) and less efficacious than tyramine. Receptor-encoding mRNA has a wide-spread distribution in the brain and subesophageal ganglion of the honeybee, suggesting that this tyramine receptor is involved in sensory signal processing as well as in higher-order brain functions.

Adverse Effects on β-Adrenergic Receptor Coupling: Ischemic Postconditioning Failed to Preserve Long-Term Cardiac Function.

Science.gov (United States)

Schreckenberg, Rolf; Bencsik, Péter; Weber, Martin; Abdallah, Yaser; Csonka, Csaba; Gömöri, Kamilla; Kiss, Krisztina; Pálóczi, János; Pipis, Judit; Sárközy, Márta; Ferdinandy, Péter; Schulz, Rainer; Schlüter, Klaus-Dieter

2017-12-22

Ischemic preconditioning (IPC) and ischemic postconditioning (IPoC) are currently among the most efficient strategies protecting the heart against ischemia/reperfusion injury. However, the effect of IPC and IPoC on functional recovery following ischemia/reperfusion is less clear, particularly with regard to the specific receptor-mediated signaling of the postischemic heart. The current article examines the effect of IPC or IPoC on the regulation and coupling of β-adrenergic receptors and their effects on postischemic left ventricular function. The β-adrenergic signal transduction was analyzed in 3-month-old Wistar rats for each of the intervention strategies (Sham, ischemia/reperfusion, IPC, IPoC) immediately and 7 days after myocardial infarction. Directly after the infarction a cardioprotective potential was demonstrated for both IPC and IPoC: the infarct size was reduced, apoptosis and production of reactive oxygen species were lowered, and the myocardial tissue was preserved. Seven days after myocardial ischemia, only IPC hearts showed significant functional improvement. Along with a deterioration in fractional shortening, IPoC hearts no longer responded adequately to β-adrenergic stimulation. The stabilization of β-adrenergic receptor kinase-2 via increased phosphorylation of Mdm2 (an E3-ubiquitin ligase) was responsible for desensitization of β-adrenergic receptors and identified as a characteristic specific to IPoC hearts. Immediately after myocardial infarction, rapid and transient activation of β-adrenergic receptor kinase-2 may be an appropriate means to protect the injured heart from excessive stress. In the long term, however, induction and stabilization of β-adrenergic receptor kinase-2, with the resultant loss of positive inotropic function, leads to the functional picture of heart failure. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Feline aminopeptidase N is not a functional receptor for avian infectious bronchitis virus

Directory of Open Access Journals (Sweden)

Harbison Carole E

2007-02-01

Full Text Available Abstract Background Coronaviruses are an important cause of infectious diseases in humans, including severe acute respiratory syndrome (SARS, and have the continued potential for emergence from animal species. A major factor in the host range of a coronavirus is its receptor utilization on host cells. In many cases, coronavirus-receptor interactions are well understood. However, a notable exception is the receptor utilization by group 3 coronaviruses, including avian infectious bronchitis virus (IBV. Feline aminopeptidase N (fAPN serves as a functional receptor for most group 1 coronaviruses including feline infectious peritonitis virus (FIPV, canine coronavirus, transmissible gastroenteritis virus (TGEV, and human coronavirus 229E (HCoV-229E. A recent report has also suggested a role for fAPN during IBV entry (Miguel B, Pharr GT, Wang C: The role of feline aminopeptidase N as a receptor for infectious bronchitis virus. Brief review. Arch Virol 2002, 147:2047–2056. Results Here we show that, whereas both transient transfection and constitutive expression of fAPN on BHK-21 cells can rescue FIPV and TGEV infection in non-permissive BHK cells, fAPN expression does not rescue infection by the prototype IBV strain Mass41. To account for the previous suggestion that fAPN could serve as an IBV receptor, we show that feline cells can be infected with the prototype strain of IBV (Mass 41, but with low susceptibility compared to primary chick kidney cells. We also show that BHK-21 cells are slightly susceptible to certain IBV strains, including Ark99, Ark_DPI, CA99, and Iowa97 ( Conclusion We conclude that fAPN is not a functional receptor for IBV, the identity of which is currently under investigation.

Human neural progenitors express functional lysophospholipid receptors that regulate cell growth and morphology

Directory of Open Access Journals (Sweden)

Callihan Phillip

2008-12-01

Full Text Available Abstract Background Lysophospholipids regulate the morphology and growth of neurons, neural cell lines, and neural progenitors. A stable human neural progenitor cell line is not currently available in which to study the role of lysophospholipids in human neural development. We recently established a stable, adherent human embryonic stem cell-derived neuroepithelial (hES-NEP cell line which recapitulates morphological and phenotypic features of neural progenitor cells isolated from fetal tissue. The goal of this study was to determine if hES-NEP cells express functional lysophospholipid receptors, and if activation of these receptors mediates cellular responses critical for neural development. Results Our results demonstrate that Lysophosphatidic Acid (LPA and Sphingosine-1-phosphate (S1P receptors are functionally expressed in hES-NEP cells and are coupled to multiple cellular signaling pathways. We have shown that transcript levels for S1P1 receptor increased significantly in the transition from embryonic stem cell to hES-NEP. hES-NEP cells express LPA and S1P receptors coupled to Gi/o G-proteins that inhibit adenylyl cyclase and to Gq-like phospholipase C activity. LPA and S1P also induce p44/42 ERK MAP kinase phosphorylation in these cells and stimulate cell proliferation via Gi/o coupled receptors in an Epidermal Growth Factor Receptor (EGFR- and ERK-dependent pathway. In contrast, LPA and S1P stimulate transient cell rounding and aggregation that is independent of EGFR and ERK, but dependent on the Rho effector p160 ROCK. Conclusion Thus, lysophospholipids regulate neural progenitor growth and morphology through distinct mechanisms. These findings establish human ES cell-derived NEP cells as a model system for studying the role of lysophospholipids in neural progenitors.

ARF6-dependent regulation of P2Y receptor traffic and function in human platelets.

Science.gov (United States)

Kanamarlapudi, Venkateswarlu; Owens, Sian E; Saha, Keya; Pope, Robert J; Mundell, Stuart J

2012-01-01

Adenosine diphosphate (ADP) is a critical regulator of platelet activation, mediating its actions through two G protein-coupled receptors, the P2Y(1) and P2Y(12) purinoceptors. Recently, we demonstrated that P2Y(1) and P2Y(12) purinoceptor activities are rapidly and reversibly modulated in human platelets, revealing that the underlying mechanism requires receptor internalization and subsequent trafficking as an essential part of this process. In this study we investigated the role of the small GTP-binding protein ADP ribosylation factor 6 (ARF6) in the internalization and function of P2Y(1) and P2Y(12) purinoceptors in human platelets. ARF6 has been implicated in the internalization of a number of GPCRs, although its precise molecular mechanism in this process remains unclear. In this study we show that activation of either P2Y(1) or P2Y(12) purinoceptors can stimulate ARF6 activity. Further blockade of ARF6 function either in cell lines or human platelets blocks P2Y purinoceptor internalization. This blockade of receptor internalization attenuates receptor resensitization. Furthermore, we demonstrate that Nm23-H1, a nucleoside diphosphate (NDP) kinase regulated by ARF6 which facilitates dynamin-dependent fission of coated vesicles during endocytosis, is also required for P2Y purinoceptor internalization. These data describe a novel function of ARF6 in the internalization of P2Y purinoceptors and demonstrate the integral importance of this small GTPase upon platelet ADP receptor function.

ARF6-dependent regulation of P2Y receptor traffic and function in human platelets.

Directory of Open Access Journals (Sweden)

Venkateswarlu Kanamarlapudi

Full Text Available Adenosine diphosphate (ADP is a critical regulator of platelet activation, mediating its actions through two G protein-coupled receptors, the P2Y(1 and P2Y(12 purinoceptors. Recently, we demonstrated that P2Y(1 and P2Y(12 purinoceptor activities are rapidly and reversibly modulated in human platelets, revealing that the underlying mechanism requires receptor internalization and subsequent trafficking as an essential part of this process. In this study we investigated the role of the small GTP-binding protein ADP ribosylation factor 6 (ARF6 in the internalization and function of P2Y(1 and P2Y(12 purinoceptors in human platelets. ARF6 has been implicated in the internalization of a number of GPCRs, although its precise molecular mechanism in this process remains unclear. In this study we show that activation of either P2Y(1 or P2Y(12 purinoceptors can stimulate ARF6 activity. Further blockade of ARF6 function either in cell lines or human platelets blocks P2Y purinoceptor internalization. This blockade of receptor internalization attenuates receptor resensitization. Furthermore, we demonstrate that Nm23-H1, a nucleoside diphosphate (NDP kinase regulated by ARF6 which facilitates dynamin-dependent fission of coated vesicles during endocytosis, is also required for P2Y purinoceptor internalization. These data describe a novel function of ARF6 in the internalization of P2Y purinoceptors and demonstrate the integral importance of this small GTPase upon platelet ADP receptor function.

Biological functionalization of drug delivery carriers to bypass size restrictions of receptor-mediated endocytosis independently from receptor targeting.

Science.gov (United States)

Ansar, Maria; Serrano, Daniel; Papademetriou, Iason; Bhowmick, Tridib Kumar; Muro, Silvia

2013-12-23

Targeting of drug carriers to cell-surface receptors involved in endocytosis is commonly used for intracellular drug delivery. However, most endocytic receptors mediate uptake via clathrin or caveolar pathways associated with ≤200-nm vesicles, restricting carrier design. We recently showed that endocytosis mediated by intercellular adhesion molecule 1 (ICAM-1), which differs from clathrin- and caveolae-mediated pathways, allows uptake of nano- and microcarriers in cell culture and in vivo due to recruitment of cellular sphingomyelinases to the plasmalemma. This leads to ceramide generation at carrier binding sites and formation of actin stress-fibers, enabling engulfment and uptake of a wide size-range of carriers. Here we adapted this paradigm to enhance uptake of drug carriers targeted to receptors associated with size-restricted pathways. We coated sphingomyelinase onto model (polystyrene) submicro- and microcarriers targeted to clathrin-associated mannose-6-phosphate receptor. In endothelial cells, this provided ceramide enrichment at the cell surface and actin stress-fiber formation, modifying the uptake pathway and enhancing carrier endocytosis without affecting targeting, endosomal transport, cell-associated degradation, or cell viability. This improvement depended on the carrier size and enzyme dose, and similar results were observed for other receptors (transferrin receptor) and cell types (epithelial cells). This phenomenon also enhanced tissue accumulation of carriers after intravenous injection in mice. Hence, it is possible to maintain targeting toward a selected receptor while bypassing natural size restrictions of its associated endocytic route by functionalization of drug carriers with biological elements mimicking the ICAM-1 pathway. This strategy holds considerable promise to enhance flexibility of design of targeted drug delivery systems.

Functional expression of Squalus acanthias melanocortin-5 receptor in CHO cells: ligand selectivity and interaction with MRAP.

Science.gov (United States)

Reinick, Christina L; Liang, Liang; Angleson, Josepha K; Dores, Robert M

2012-04-05

The melanocortin-5 receptor (MC(5)) of the dogfish Squalus acanthias (SacMC(5) receptor) can be functionally expressed in CHO cells in the absence of the co-expression of an exogenous MRAP cDNA. Both human ACTH(1-24) and dogfish ACTH(1-25) were much better stimulators of the SacMC(5) receptor than any of the mammalian or dogfish MSH ligands that were tested. The order of ligand selectivity for the dogfish melanocortins was ACTH(1-25)>αMSH>γ-MSH=δ-MSH>β-MSH. Unlike mammalian MC(5) receptors, the functional expression of the SacMC(5) receptor was not negatively impacted when the receptor was co-expressed with a cartilaginous fish (Callorhinchus milii) MRAP2 cDNA. However, co-expression with either mouse mMRAP1 or zebrafish zfMRAP1 increased the sensitivity of SacMC(5) receptor for hACTH(1-24) by at least one order of magnitude. Hence, SacMC(5) receptor has the potential to interact with MRAP1 orthologs and in this regard behaved more like a melanocortin MC(2) receptor ortholog than a melanocortin MC(5) receptor ortholog. These observations are discussed in light of the evolution of the melanocortin receptor gene family in cartilaginous fish, and the physiological implications of these observations are considered. Copyright © 2012 Elsevier B.V. All rights reserved.

The Moderating Role of Sensory Overresponsivity in HPA Activity: A Pilot Study with Children Diagnosed with ADHD

Science.gov (United States)

Reynolds, Stacey; Lane, Shelly J.; Gennings, Chris

2010-01-01

Objective: To determine if sensory overresponsivity (SOR) is a moderating condition impacting the activity of the Hypothalamic Pituitary Adrenal (HPA) Axis in children with ADHD. Method: Participants were children with (n = 24) and without ADHD (n = 24). Children in the ADHD group were divided into SOR (ADHDs) and non-SOR (ADHDt) groups using the…

Do different data analytic approaches generate discrepant findings when measuring mother-infant HPA axis attunement?

Science.gov (United States)

Bernard, Nicola K; Kashy, Deborah A; Levendosky, Alytia A; Bogat, G Anne; Lonstein, Joseph S

2017-03-01

Attunement between mothers and infants in their hypothalamic-pituitary-adrenal (HPA) axis responsiveness to acute stressors is thought to benefit the child's emerging physiological and behavioral self-regulation, as well as their socioemotional development. However, there is no universally accepted definition of attunement in the literature, which appears to have resulted in inconsistent statistical analyses for determining its presence or absence, and contributed to discrepant results. We used a series of data analytic approaches, some previously used in the attunement literature and others not, to evaluate the attunement between 182 women and their 1-year-old infants in their HPA axis responsivity to acute stress. Cortisol was measured in saliva samples taken from mothers and infants before and twice after a naturalistic laboratory stressor (infant arm restraint). The results of the data analytic approaches were mixed, with some analyses suggesting attunement while others did not. The strengths and weaknesses of each statistical approach are discussed, and an analysis using a cross-lagged model that considered both time and interactions between mother and infant appeared the most appropriate. Greater consensus in the field about the conceptualization and analysis of physiological attunement would be valuable in order to advance our understanding of this phenomenon. © 2016 Wiley Periodicals, Inc.

Regulation of NKG2D-Dependent NK Cell Functions: The Yin and the Yang of Receptor Endocytosis

Directory of Open Access Journals (Sweden)

Rosa Molfetta

2017-08-01

Full Text Available Natural-killer receptor group 2, member D (NKG2D is a well characterized natural killer (NK cell activating receptor that recognizes several ligands poorly expressed on healthy cells but up-regulated upon stressing stimuli in the context of cancer or viral infection. Although NKG2D ligands represent danger signals that render target cells more susceptible to NK cell lysis, accumulating evidence demonstrates that persistent exposure to ligand-expressing cells causes the decrease of NKG2D surface expression leading to a functional impairment of NKG2D-dependent NK cell functions. Upon ligand binding, NKG2D is internalized from the plasma membrane and sorted to lysosomes for degradation. However, receptor endocytosis is not only a mechanism of receptor clearance from the cell surface, but is also required for the proper activation of signalling events leading to the functional program of NK cells. This review is aimed at providing a summary of current literature relevant to the molecular mechanisms leading to NKG2D down-modulation with particular emphasis given to the role of NKG2D endocytosis in both receptor degradation and signal propagation. Examples of chronic ligand-induced down-regulation of NK cell activating receptors other than NKG2D, including natural cytotoxicity receptors (NCRs, DNAX accessory molecule-1 (DNAM1 and CD16, will be also discussed.

Blockade of human P2X7 receptor function with a monoclonal antibody.

Science.gov (United States)

Buell, G; Chessell, I P; Michel, A D; Collo, G; Salazzo, M; Herren, S; Gretener, D; Grahames, C; Kaur, R; Kosco-Vilbois, M H; Humphrey, P P

1998-11-15

A monoclonal antibody (MoAb) specific for the human P2X7 receptor was generated in mice. As assessed by flow cytometry, the MoAb labeled human blood-derived macrophage cells natively expressing P2X7 receptors and cells transfected with human P2X7 but not other P2X receptor types. The MoAb was used to immunoprecipitate the human P2X7 receptor protein, and in immunohistochemical studies on human lymphoid tissue, P2X7 receptor labeling was observed within discrete areas of the marginal zone of human tonsil sections. The antibody also acted as a selective antagonist of human P2X7 receptors in several functional studies. Thus, whole cell currents, elicited by the brief application of 2',3'-(4-benzoyl)-benzoyl-ATP in cells expressing human P2X7, were reduced in amplitude by the presence of the MoAb. Furthermore, preincubation of human monocytic THP-1 cells with the MoAb antagonized the ability of P2X7 agonists to induce the release of interleukin-1beta.

Cardiac microvascular endothelial cells express a functional Ca+ -sensing receptor.

Science.gov (United States)

Berra Romani, Roberto; Raqeeb, Abdul; Laforenza, Umberto; Scaffino, Manuela Federica; Moccia, Francesco; Avelino-Cruz, Josè Everardo; Oldani, Amanda; Coltrini, Daniela; Milesi, Veronica; Taglietti, Vanni; Tanzi, Franco

2009-01-01

The mechanism whereby extracellular Ca(2+) exerts the endothelium-dependent control of vascular tone is still unclear. In this study, we assessed whether cardiac microvascular endothelial cells (CMEC) express a functional extracellular Ca(2+)-sensing receptor (CaSR) using a variety of techniques. CaSR mRNA was detected using RT-PCR, and CaSR protein was identified by immunocytochemical analysis. In order to assess the functionality of the receptor, CMEC were loaded with the Ca(2+)-sensitive fluorochrome, Fura-2/AM. A number of CaSR agonists, such as spermine, Gd(3+), La(3+) and neomycin, elicited a heterogeneous intracellular Ca(2+) signal, which was abolished by disruption of inositol 1,4,5-trisphosphate (InsP(3)) signaling and by depletion of intracellular stores with cyclopiazonic acid. The inhibition of the Na(+)/Ca(2+) exchanger upon substitution of extracellular Na(+) unmasked the Ca(2+) signal triggered by an increase in extracellular Ca(2+) levels. Finally, aromatic amino acids, which function as allosteric activators of CaSR, potentiated the Ca(2+) response to the CaSR agonist La(3+). These data provide evidence that CMEC express CaSR, which is able to respond to physiological agonists by mobilizing Ca(2+) from intracellular InsP(3)-sensitive stores. Copyright 2008 S. Karger AG, Basel.

Investigation of the hypothalamo-pituitary-adrenal axis (HPA) by 1 microg ACTH test and metyrapone test in patients with primary fibromyalgia syndrome.

Science.gov (United States)

Calis, M; Gökçe, C; Ates, F; Ulker, S; Izgi, H B; Demir, H; Kirnap, M; Sofuoglu, S; Durak, A C; Tutus, A; Kelestimur, F

2004-01-01

Primary fibromyalgia syndrome (PFS) is characterized by widespread chronic pain that affects the musculoskeletal system, fatigue, anxiety, sleep disturbance, headache and postural hypotension. The pathophysiology of PFS is unknown. The hypothalamic-pituitary-adrenal (HPA) axis seems to play an important role in PFS. Both hyperactivity and hypoactivity of the HPA axis have been reported in patients with PFS. In this study we assessed the HPA axis by 1 microg ACTH stimulation test and metyrapone test in 22 patients with PFS and in 15 age-, sex-, and body mass index (BMI)- matched controls. Metyrapone (30 mg/kg) was administered orally at 23:00 h and blood was sampled at 08:30 h the following morning for 11-deoxycortisol. ACTH stimulation test was carried out by using 1 microg (iv) ACTH as a bolus injection after an overnight fast, and blood samples were drawn at 0, 30 and 60 min. Peak cortisol level (659.4 +/- 207.2 nmol/l) was lower in the patients with PFS than peak cortisol level (838.7 +/- 129.6 nmol/l) in the control subjects (p < 0.05). Ten patients (45%) with PFS had peak cortisol responses to 1 microg ACTH test lower than the lowest peak cortisol detected in healthy controls. After metyrapone test 11-deoxycortisol level was 123.7 +/- 26 nmol/l in patients with PFS and 184.2 +/- 17.3 nmol/l in the controls (p < 0.05). Ninety five percent of the patients with PFS had lower 11-deoxycortisol level after metyrapone than the lowest 11-deoxycortisol level after metyrapone detected in healthy controls. We also compared the adrenal size of the patients with that of the healthy subjects and we found that the adrenal size between the groups was similar. This study clearly shows that HPA axis is underactivated in PFS, rather than overactivated.

A bovine papillomavirus-1 based vector restores the function of the low-density lipoprotein receptor in the receptor-deficient CHO-ldlA7 cell line

Directory of Open Access Journals (Sweden)

Ustav Mart

2002-04-01

Full Text Available Abstract Background The rationale of using bovine papillomavirus-1 (BPV-1 derived vectors in gene therapy protocols lies in their episomal maintenance at intermediate to high copy number, and stable, high-level expression of the gene products. We constructed the BPV-1 based vector harbouring the human low-density lipoprotein receptor (LDLR gene cDNA and tested its ability to restore the function of the LDLR in the receptor-deficient cell line CHO-ldlA7. Results The introduced vector p3.7LDL produced functionally active LDL receptors in the receptor-deficient cell line CHO-ldlA7 during the 32-week period of observation as determined by the internalisation assay with the labelled LDL particles. Conclusion Bovine papillomavirus type-1 (BPV-1-derived vectors could be suitable for gene therapy due to their episomal maintenance at intermediate to high copy number and stable, high-level expression of the gene products. The constructed BPV-1 based vector p3.7LDL produced functionally active LDL receptors in the LDLR-deficient cell line CHO-ldlA7 during the 32-week period of observation. In vivo experiments should reveal, whether 1–5% transfection efficiency obtained in the current work is sufficient to bring about detectable and clinically significant lowering of the amount of circulating LDL cholesterol particles.

Design and Discovery of Functionally Selective Serotonin 2C (5-HT2C) Receptor Agonists.

Science.gov (United States)

Cheng, Jianjun; McCorvy, John D; Giguere, Patrick M; Zhu, Hu; Kenakin, Terry; Roth, Bryan L; Kozikowski, Alan P

2016-11-10

On the basis of the structural similarity of our previous 5-HT 2C agonists with the melatonin receptor agonist tasimelteon and the putative biological cross-talk between serotonergic and melatonergic systems, a series of new (2,3-dihydro)benzofuran-based compounds were designed and synthesized. The compounds were evaluated for their selectivity toward 5-HT 2A , 5-HT 2B , and 5-HT 2C receptors in the calcium flux assay with the ultimate goal to generate selective 5-HT 2C agonists. Selected compounds were studied for their functional selectivity by comparing their transduction efficiency at the G protein signaling pathway versus β-arrestin recruitment. The most functionally selective compound (+)-7e produced weak β-arrestin recruitment and also demonstrated less receptor desensitization compared to serotonin in both calcium flux and phosphoinositide (PI) hydrolysis assays. We report for the first time that selective 5-HT 2C agonists possessing weak β-arrestin recruitment can produce distinct receptor desensitization properties.

A robust and rapid method of producing soluble, stable, and functional G-protein coupled receptors.

Directory of Open Access Journals (Sweden)

Karolina Corin

Full Text Available Membrane proteins, particularly G-protein coupled receptors (GPCRs, are notoriously difficult to express. Using commercial E. coli cell-free systems with the detergent Brij-35, we could rapidly produce milligram quantities of 13 unique GPCRs. Immunoaffinity purification yielded receptors at >90% purity. Secondary structure analysis using circular dichroism indicated that the purified receptors were properly folded. Microscale thermophoresis, a novel label-free and surface-free detection technique that uses thermal gradients, showed that these receptors bound their ligands. The secondary structure and ligand-binding results from cell-free produced proteins were comparable to those expressed and purified from HEK293 cells. Our study demonstrates that cell-free protein production using commercially available kits and optimal detergents is a robust technology that can be used to produce sufficient GPCRs for biochemical, structural, and functional analyses. This robust and simple method may further stimulate others to study the structure and function of membrane proteins.

Pharmacologic perspectives of functional selectivity by the angiotensin II type 1 receptor

DEFF Research Database (Denmark)

Aplin, Mark; Christensen, Gitte Lund; Hansen, Jakob Lerche

2008-01-01

and to sudden injury occurring in the circulatory system. Hence, current drugs that block all AT(1) receptor actions most likely leave room for improvement. Recent developments show that two major signaling pathways used by the AT(1) receptor may be dissected by pharmacologic means. Key pathologic responses...... protein actions and simultaneous activation of G protein-dependent or -independent signaling could therefore be desirable in certain situations. The previously unappreciated concept of "functional selectivity" makes this exact strategy feasible and may yield improved drugs for cardiovascular therapy....

The insulin receptor substrate (IRS)-1 pleckstrin homology domain functions in downstream signaling.

Science.gov (United States)

Vainshtein, I; Kovacina, K S; Roth, R A

2001-03-16

The pleckstrin homology (PH) domain of the insulin receptor substrate-1 (IRS-1) plays a role in directing this molecule to the insulin receptor, thereby regulating its tyrosine phosphorylation. In this work, the role of the PH domain in subsequent signaling was studied by constructing constitutively active forms of IRS-1 in which the inter-SH2 domain of the p85 subunit of phosphatidylinositol 3-kinase was fused to portions of the IRS-1 molecule. Chimeric molecules containing the PH domain were found to activate the downstream response of stimulating the Ser/Thr kinase Akt. A chimera containing point mutations in the PH domain that abolished the ability of this domain to bind phosphatidylinositol 4,5-bisphosphate prevented these molecules from activating Akt. These mutations also decreased by about 70% the amount of the constructs present in a particulate fraction of the cells. These results indicate that the PH domain of IRS-1, in addition to directing this protein to the receptor for tyrosine phosphorylation, functions in the ability of this molecule to stimulate subsequent responses. Thus, compromising the function of the PH domain, e.g. in insulin-resistant states, could decrease both the ability of IRS-1 to be tyrosine phosphorylated by the insulin receptor and to link to subsequent downstream targets.

Expression and function of androgen receptor coactivator p44/Mep50/WDR77 in ovarian cancer.

Directory of Open Access Journals (Sweden)

Martin Ligr

Full Text Available Hormones, including estrogen and progesterone, and their receptors play an important role in the development and progression of ovarian carcinoma. Androgen, its receptor and coactivators have also been implicated in these processes. p44/Mep50/WDR77 was identified as a subunit of the methylosome complex and lately characterized as a steroid receptor coactivator that enhances androgen receptor as well as estrogen receptor-mediated transcriptional activity in a ligand-dependent manner. We previously described distinct expression and function of p44 in prostate, testis, and breast cancers. In this report, we examined the expression and function of p44 in ovarian cancer. In contrast to findings in prostate and testicular cancer and similar to breast cancer, p44 shows strong cytoplasmic localization in morphologically normal ovarian surface and fallopian tube epithelia, while nuclear p44 is observed in invasive ovarian carcinoma. We observed that p44 can serve as a coactivator of both androgen receptor (AR and estrogen receptor (ER in ovarian cells. Further, overexpression of nuclear-localized p44 stimulates proliferation and invasion in ovarian cancer cells in the presence of estrogen or androgen. These findings strongly suggest that p44 plays a role in mediating the effects of hormones during ovarian tumorigenesis.

Different structural requirements for functional ion pore transplantation suggest different gating mechanisms of NMDA and kainate receptors.

Science.gov (United States)

Villmann, Carmen; Hoffmann, Jutta; Werner, Markus; Kott, Sabine; Strutz-Seebohm, Nathalie; Nilsson, Tanja; Hollmann, Michael

2008-10-01

Although considerable progress has been made in characterizing the physiological function of the high-affinity kainate (KA) receptor subunits KA1 and KA2, no homomeric ion channel function has been shown. An ion channel transplantation approach was employed in this study to directly test if homomerically expressed KA1 and KA2 pore domains are capable of conducting currents. Transplantation of the ion pore of KA1 or KA2 into GluR6 generated perfectly functional ion channels that allowed characterization of those electrophysiological and pharmacological properties that are determined exclusively by the ion pore of KA1 or KA2. This demonstrates for the first time that KA1 and KA2 ion pore domains are intrinsically capable of conducting ions even in homomeric pore assemblies. NMDA receptors, similar to KA1- or KA2-containing receptors, function only as heteromeric complexes. They are composed of NR1 and NR2 subunits, which both are non-functional when expressed homomerically. In contrast to NR1, the homomeric NR2B ion pore failed to translate ligand binding into pore opening when transplanted into GluR6. Similarly, heteromeric coexpression of the ion channel domains of both NR1 and NR2 inserted into GluR6 failed to produce functional channels. Therefore, we conclude that the mechanism underlying the ion channel opening in the obligatorily heterotetrameric NMDA receptors differs significantly from that in the facultatively heterotetrameric alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate and KA receptors.

Association of HPA axis-related genetic variation with stress reactivity and aggressive behaviour in pigs

Directory of Open Access Journals (Sweden)

Muráni Eduard

2010-08-01

Full Text Available Abstract Background Stress, elicited for example by aggressive interactions, has negative effects on various biological functions including immune defence, reproduction, growth, and, in livestock, on product quality. Stress response and aggressiveness are mutually interrelated and show large interindividual variation, partly attributable to genetic factors. In the pig little is known about the molecular-genetic background of the variation in stress responsiveness and aggressiveness. To identify candidate genes we analyzed association of DNA markers in each of ten genes (CRH g.233C>T, CRHR1 c.*866_867insA, CRHBP c.51G>A, POMC c.293_298del, MC2R c.306T>G, NR3C1 c.*2122A>G, AVP c.207A>G, AVPR1B c.1084A>G, UCN g.1329T>C, CRHR2 c.*13T>C related to the hypothalamic-pituitary-adrenocortical (HPA axis, one of the main stress-response systems, with various stress- and aggression-related parameters at slaughter. These parameters were: physiological measures of the stress response (plasma concentrations of cortisol, creatine kinase, glucose, and lactate, adrenal weight (which is a parameter reflecting activity of the central branch of the HPA axis over time and aggressive behaviour (measured by means of lesion scoring in the context of psychosocial stress of mixing individuals with different aggressive temperament. Results The SNP NR3C1 c.*2122A>G showed association with cortisol concentration (p = 0.024, adrenal weight (p = 0.003 and aggressive behaviour (front lesion score, p = 0.012; total lesion score p = 0.045. The SNP AVPR1B c.1084A>G showed a highly significant association with aggressive behaviour (middle lesion score, p = 0.007; total lesion score p = 0.003. The SNP UCN g.1329T>C showed association with adrenal weight (p = 0.019 and aggressive behaviour (front lesion score, p = 0.029. The SNP CRH g.233C>T showed a significant association with glucose concentration (p = 0.002, and the polymorphisms POMC c.293_298del and MC2R c.306T>G with adrenal

Functionally heterogenous ryanodine receptors in avian cerebellum.

Science.gov (United States)

Sierralta, J; Fill, M; Suárez-Isla, B A

1996-07-19

The functional heterogeneity of the ryanodine receptor (RyR) channels in avian cerebellum was defined. Heavy endoplasmic reticulum microsomes had significant levels of ryanodine and inositol 1,4,5-trisphosphate binding. Scatchard analysis and kinetic studies indicated the existence of at least two distinct ryanodine binding sites. Ryanodine binding was calcium-dependent but was not significantly enhanced by caffeine. Incorporation of microsomes into planar lipid bilayers revealed ion channels with pharmacological features (calcium, magnesium, ATP, and caffeine sensitivity) similar to the RyR channels found in mammalian striated muscle. Despite a wide range of unitary conductances (220-500 picosiemens, symmetrical cesium methanesulfonate), ryanodine locked both channels into a characteristic slow gating subconductance state, positively identifying them as RyR channels. Two populations of avian RyR channels were functionally distinguished by single channel calcium sensitivity. One population was defined by a bell-shaped calcium sensitivity analogous to the skeletal muscle RyR isoform (type I). The calcium sensitivity of the second RyR population was sigmoidal and analogous to the cardiac muscle RyR isoform (type II). These data show that there are at least two functionally distinct RyR channel populations in avian cerebellum. This leads to the possibility that these functionally distinct RyR channels are involved in different intracellular calcium signaling pathways.

P2X7 Receptor Function in Bone-Related Cancer

Directory of Open Access Journals (Sweden)

Elena Adinolfi

2012-01-01

Full Text Available Modulation of tumor microenvironment by different mediators is central in determining neoplastic formation and progression. Among these molecules extracellular ATP is emerging as a good candidate in promoting cell growth, neovascularization, tumor-host interactions, and metastatization. This paper summarizes recent findings on expression and function of P2X7 receptor for extracellular ATP in primary and metastatic bone cancers. Search of mRNA expression microchip databases and literature analysis demonstrate a high expression of P2X7 in primary bone tumors as well as in other malignancies such as multiple myeloma, neuroblastoma, breast, and prostate cancer. Evidence that P2X7 triggers NFATc1, PI3K/Akt, ROCK, and VEGF pathways in osteoblasts promoting either primary tumor development or osteoblastic lesions is also reported. Moreover, P2X7 receptor is involved in osteoclast differentiation, RANKL expression, matrix metalloproteases and cathepsin secretion thus promoting bone resorption and osteolytic lesions. Taken together these data point to a pivotal role for the P2X7 receptor in bone cancer biology.

Organophosphorus pesticides decrease M2 muscarinic receptor function in guinea pig airway nerves via indirect mechanisms.

Directory of Open Access Journals (Sweden)

Becky J Proskocil

Full Text Available BACKGROUND: Epidemiological studies link organophosphorus pesticide (OP exposures to asthma, and we have shown that the OPs chlorpyrifos, diazinon and parathion cause airway hyperreactivity in guinea pigs 24 hr after a single subcutaneous injection. OP-induced airway hyperreactivity involves M2 muscarinic receptor dysfunction on airway nerves independent of acetylcholinesterase (AChE inhibition, but how OPs inhibit neuronal M2 receptors in airways is not known. In the central nervous system, OPs interact directly with neurons to alter muscarinic receptor function or expression; therefore, in this study we tested whether the OP parathion or its oxon metabolite, paraoxon, might decrease M2 receptor function on peripheral neurons via similar direct mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: Intravenous administration of paraoxon, but not parathion, caused acute frequency-dependent potentiation of vagally-induced bronchoconstriction and increased electrical field stimulation (EFS-induced contractions in isolated trachea independent of AChE inhibition. However, paraoxon had no effect on vagally-induced bradycardia in intact guinea pigs or EFS-induced contractions in isolated ileum, suggesting mechanisms other than pharmacologic antagonism of M2 receptors. Paraoxon did not alter M2 receptor expression in cultured cells at the mRNA or protein level as determined by quantitative RT-PCR and radio-ligand binding assays, respectively. Additionally, a biotin-labeled fluorophosphonate, which was used as a probe to identify molecular targets phosphorylated by OPs, did not phosphorylate proteins in guinea pig cardiac membranes that were recognized by M2 receptor antibodies. CONCLUSIONS/SIGNIFICANCE: These data indicate that neither direct pharmacologic antagonism nor downregulated expression of M2 receptors contributes to OP inhibition of M2 function in airway nerves, adding to the growing evidence of non-cholinergic mechanisms of OP neurotoxicity.

Stability analysis of a hypothalamic-pituitary-adrenal axis model with inclusion of glucocorticoid receptor and memory

Science.gov (United States)

Kaslik, Eva; Navolan, Dan Bogdan; Neamţu, Mihaela

2017-01-01

This paper analyzes a four-dimensional model of the hypothalamic-pituitary-adrenal (HPA) axis that includes the influence of the glucocorticoid receptor in the pituitary. Due to the spatial separation between the hypothalamus, pituitary and adrenal glands, distributed time delays are introduced in the mathematical model. The existence of the positive equilibrium point is proved and a local stability and bifurcation analysis is provided, considering several types of delay kernels. The fractional-order model with discrete time delays is also taken into account. Numerical simulations are provided to illustrate the effectiveness of the theoretical findings.

Vitamin D receptor B1 and exon 1d: functional and evolutionary analysis.

Science.gov (United States)

Gardiner, Edith M; Esteban, Luis M; Fong, Colette; Allison, Susan J; Flanagan, Judith L; Kouzmenko, Alexander P; Eisman, John A

2004-05-01

The vitamin D receptor (VDR) shares a conserved structural and functional organization with other nuclear receptor (NR) superfamily members. For many NRs, N-terminal variant isoforms that display distinct cell-, stage- and promoter-specific actions have been identified. The novel VDR isoform VDRB1, with a 50 amino acid N-terminal extension, is produced from low abundance transcripts that contain exon 1d of the human VDR locus. There is evidence for the conservation of this exon in other mammalian and avian species. The transactivation differences between VDRB1 and the original VDR, clarified here, provide insights into mechanisms that may contribute to functional differences and potentially distinct physiological roles for these two VDR isoforms.

Role of the Wnt receptor Frizzled-1 in presynaptic differentiation and function

Directory of Open Access Journals (Sweden)

Alvarez Alejandra R

2009-11-01

Full Text Available Abstract Background The Wnt signaling pathway regulates several fundamental developmental processes and recently has been shown to be involved in different aspects of synaptic differentiation and plasticity. Some Wnt signaling components are localized at central synapses, and it is thus possible that this pathway could be activated at the synapse. Results We examined the distribution of the Wnt receptor Frizzled-1 in cultured hippocampal neurons and determined that this receptor is located at synaptic contacts co-localizing with presynaptic proteins. Frizzled-1 was found in functional synapses detected with FM1-43 staining and in synaptic terminals from adult rat brain. Interestingly, overexpression of Frizzled-1 increased the number of clusters of Bassoon, a component of the active zone, while treatment with the extracellular cysteine-rich domain (CRD of Frizzled-1 decreased Bassoon clustering, suggesting a role for this receptor in presynaptic differentiation. Consistent with this, treatment with the Frizzled-1 ligand Wnt-3a induced presynaptic protein clustering and increased functional presynaptic recycling sites, and these effects were prevented by co-treatment with the CRD of Frizzled-1. Moreover, in synaptically mature neurons Wnt-3a was able to modulate the kinetics of neurotransmitter release. Conclusion Our results indicate that the activation of the Wnt pathway through Frizzled-1 occurs at the presynaptic level, and suggest that the synaptic effects of the Wnt signaling pathway could be modulated by local activation through synaptic Frizzled receptors.

Do unliganded thyroid hormone receptors have physiological functions?

Science.gov (United States)

Chassande, O

2003-08-01

Thyroid hormone (TH) is required for the development of vertebrates and exerts numerous homeostatic functions in adults. TH acts through nuclear receptors which control the transcription of target genes. Unliganded and liganded thyroid hormone receptors (TRs) have been shown to exert opposite effects on the transcription of target genes in vitro. However, the occurance of an aporeceptor activity in vivo and its potential physiological significance has not been clearly addressed. Several data generated using experimental hypothyroidism and thyrotoxicosis in wild type and TR knockout mice support the notion that apoTRs have an intrinsic activity in several tIssues. ApoTRs, and in particular TRalpha1, are predominant during the early stages of vertebrate development and must be turned into holoTRs for post-natal development to proceed normally. However, the absence of striking alterations of embryonic and fetal development in mice devoid of TRs indicates that apoTRs do not play a fundamental role. During development, as well as in adults, apoTRs rather appears as a system which increases the range of transcriptional responses to moderate variations of T3.

Central serotonergic and noradrenergic receptors in functional dyspepsia

Institute of Scientific and Technical Information of China (English)

S O'Mahony; TG Dinan; PW Keeling; ASB Chua

2006-01-01

Functional dyspepsia is a symptom complex characterised by upper abdominal discomfort or pain, early satiety,motor abnormalities, abdominal bloating and nausea in the absence of organic disease. The central nervous system plays an important role in the conducting and processing of visceral signals. Alterations in brain processing of pain, perception and affective responses may be key factors in the pathogenesis of functional dyspepsia. Central serotonergic and noradrenergic receptor systems are involved in the processing of motor,sensory and secretory activities of the gastrointestinal tract. Visceral hypersensitivity is currently regarded as the mechanism responsible for both motor alterations and abdominal pain in functional dyspepsia. Some studies suggest that there are alterations in central serotonergic and noradrenergic systems which may partially explain some of the symptoms of functional dyspepsia. Alterations in the autonomic nervous system may be implicated in the motor abnormalities and increases in visceral sensitivity in these patients.Noradrenaline is the main neurotransmitter in the sympathetic nervous system and again alterations in the functioning of this system may lead to changes in motor function. Functional dyspepsia causes considerable burden on the patient and society. The pathophysiology of functional dyspepsia is not fully understood but alterations in central processing by the serotonergic and noradrenergic systems may provide plausible explanations for at least some of the symptoms and offer possible treatment targets for the future.

The pathophysiological functions mediated by D-1 dopamine receptors

International Nuclear Information System (INIS)

Goldstein, M.; Kuga, S.; Meller, E.; SHimizu, Y.

1986-01-01

This chapter describes some behavioral responses which might be mediated by D 1 and D 2 DA receptors, and the authors discuss their clinical relevance. It was of considerable interest to determine whether a selective D 1 DA antagonist, such as SCH 23390, will induce catalepsy and whether this behavior is mediated by D 1 , or by both D 1 and D 2 DA receptors. Rats were used in the experiments. The authors examined whether the addition of the S 2 antagonist ketanserin affects the displacement of 3 H-Spi by SCH 23390. Induction of self-mutilating biting (SMB) behavior in monkeys with unilateral ventromedial tegmental (VMT) lesions by DA agonists and its prevention by DA antagonists is examined. The authors also discuss the possible relationships between abnormal guanine nucleotide metabolism and dopaminergic neuronal function through the implications in LeschNyhan syndrome and in some mental disorders

Molecular Mechanisms Underlying the Link between Nuclear Receptor Function and Cholesterol Gallstone Formation

Directory of Open Access Journals (Sweden)

Mary Carmen Vázquez

2012-01-01

Full Text Available Cholesterol gallstone disease is highly prevalent in western countries, particularly in women and some specific ethnic groups. The formation of water-insoluble cholesterol crystals is due to a misbalance between the three major lipids present in the bile: cholesterol, bile salts, and phospholipids. Many proteins implicated in biliary lipid secretion in the liver are regulated by several transcription factors, including nuclear receptors LXR and FXR. Human and murine genetic, physiological, pathophysiological, and pharmacological evidence is consistent with the relevance of these nuclear receptors in gallstone formation. In addition, there is emerging data that also suggests a role for estrogen receptor ESR1 in abnormal cholesterol metabolism leading to gallstone disease. A better comprehension of the role of nuclear receptor function in gallstone formation may help to design new and more effective therapeutic strategies for this highly prevalent disease condition.

TAM receptor tyrosine kinase function and the immunopathology of liver disease.

Science.gov (United States)

Mukherjee, S K; Wilhelm, A; Antoniades, C G

2016-06-01

Tyro3, Axl, MERTK (TAM) receptor tyrosine kinases are implicated in the regulation of the innate immune response through clearance of apoptotic cellular debris and control of cytokine signaling cascades. As a result they are pivotal in regulating the inflammatory response to tissue injury. Within the liver, immune regulatory signaling is employed to prevent the overactivation of innate immunity in response to continual antigenic challenge from the gastrointestinal tract. In this review we appraise current understanding of the role of TAM receptor function in the regulation of both innate and adaptive immunity, with a focus on its impact upon hepatic inflammatory pathology. Copyright © 2016 the American Physiological Society.

Androgen receptor function links human sexual dimorphism to DNA methylation.

Directory of Open Access Journals (Sweden)

Ole Ammerpohl

Full Text Available Sex differences are well known to be determinants of development, health and disease. Epigenetic mechanisms are also known to differ between men and women through X-inactivation in females. We hypothesized that epigenetic sex differences may also result from sex hormone functions, in particular from long-lasting androgen programming. We aimed at investigating whether inactivation of the androgen receptor, the key regulator of normal male sex development, is associated with differences of the patterns of DNA methylation marks in genital tissues. To this end, we performed large scale array-based analysis of gene methylation profiles on genomic DNA from labioscrotal skin fibroblasts of 8 males and 26 individuals with androgen insensitivity syndrome (AIS due to inactivating androgen receptor gene mutations. By this approach we identified differential methylation of 167 CpG loci representing 162 unique human genes. These were significantly enriched for androgen target genes and low CpG content promoter genes. Additional 75 genes showed a significant increase of heterogeneity of methylation in AIS compared to a high homogeneity in normal male controls. Our data show that normal and aberrant androgen receptor function is associated with distinct patterns of DNA-methylation marks in genital tissues. These findings support the concept that transcription factor binding to the DNA has an impact on the shape of the DNA methylome. These data which derived from a rare human model suggest that androgen programming of methylation marks contributes to sexual dimorphism in the human which might have considerable impact on the manifestation of sex-associated phenotypes and diseases.

Interaction Between 5-HTTLPR and BDNF Val66Met Polymorphisms on HPA Axis Reactivity in Preschoolers

OpenAIRE

Dougherty, Lea R.; Klein, Daniel N.; Congdon, Eliza; Canli, Turhan; Hayden, Elizabeth P.

2009-01-01

This study examined whether the interaction between the serotonin transporter promoter region (5-HTTLPR) and brain-derived neurotrophic factor (BDNF) Val66Met polymorphisms was associated with hypothalamic-pituitary-adrenal (HPA) axis reactivity to stress. A community sample of 144 preschool-aged children was genotyped and exposed to stress-inducing laboratory tasks. Salivary cortisol was obtained at four time points during a standardized laboratory assessment before and after stressors invol...

Functional recovery of supersensitive dopamine receptors after intrastriatal grafts of fetal substantia nigra

International Nuclear Information System (INIS)

Dawson, T.M.; Dawson, V.L.; Gage, F.H.; Fisher, L.J.; Hunt, M.A.; Wamsley, J.K.

1991-01-01

Interruption of the ascending dopamine neurons of the nigrostriatal pathway, by 6-hydroxydopamine (6-OHDA) lesion in rats, produced a significant loss of the dopamine transport complexes labeled with the phencyclidine derivative [3H]BTCP. This loss of dopamine innervation in the striatum was present at least 12 to 14 months after lesioning and was functionally manifested by ipsilateral rotation of the animals in response to amphetamine. In these same animals, in comparison to controls, there was a significant increase in the number (Bmax) of [3H]SCH 23390-labeled D-1 receptors in the striatum (36.7%) and the substantia nigra (35.1%) and a 54.4% increase in the number (Bmax) of [3H]sulpiride-labeled striatal D-2 receptors without an apparent change in affinity (Kd). Ten to twelve months after the transplantation of homologous fetal substantia nigra into the denervated striatum, there was a significant decrease in amphetamine-induced turning behavior. In these animals, there was an ingrowth of dopamine nerve terminals in the striatum as demonstrated by a return of [3H]BTCP binding. Accompanying this reinnervation was the normalization of D-1 and D-2 receptors to control values in the striatum as well as the return of D-1 receptors to prelesion densities in the substantia nigra. In a subgroup of transplanted rats, amphetamine continued to induce ipsilateral turning. In these animals both D-1 and D-2 receptors remained supersensitive. These results support the hypothesis that the functional recovery of transplanted animals is due, in part, to reinnervation of the striatum. In addition, long-term alterations in receptor density may be related to the behavioral deficits that are associated with the 6-OHDA-lesioned rat

Insulin receptors

International Nuclear Information System (INIS)

Kahn, C.R.; Harrison, L.C.

1988-01-01

This book contains the proceedings on insulin receptors. Part A: Methods for the study of structure and function. Topics covered include: Method for purification and labeling of insulin receptors, the insulin receptor kinase, and insulin receptors on special tissues

Modern approaches to the design of memory and cognitive function stimulants based on AMPA receptor ligands

International Nuclear Information System (INIS)

Grigoriev, V V; Proshin, A N; Kinzirsky, A S; Bachurin, Sergey O

2009-01-01

Data on the structure and properties of compounds acting on AMPA receptors, the key subtype of ionotropic glutamate receptors of the mammalian central nervous system, are analyzed. Data on the role of these receptors in provision of memory and cognitive function formation and impairment processes are presented. The attention is focused on the modern views on the mechanisms of AMPA receptor desensitization and deactivation and action of substances affecting these processes. The structures of key positive modulators of AMPA receptors are given. The problems of application of these substances as therapeutic means for preventing and treating neurodegenerative and psychoneurological diseases are discussed. Bibliography - 121 references.

Modern approaches to the design of memory and cognitive function stimulants based on AMPA receptor ligands

Energy Technology Data Exchange (ETDEWEB)

Grigoriev, V V; Proshin, A N; Kinzirsky, A S; Bachurin, Sergey O [Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

2009-05-31

Data on the structure and properties of compounds acting on AMPA receptors, the key subtype of ionotropic glutamate receptors of the mammalian central nervous system, are analyzed. Data on the role of these receptors in provision of memory and cognitive function formation and impairment processes are presented. The attention is focused on the modern views on the mechanisms of AMPA receptor desensitization and deactivation and action of substances affecting these processes. The structures of key positive modulators of AMPA receptors are given. The problems of application of these substances as therapeutic means for preventing and treating neurodegenerative and psychoneurological diseases are discussed. Bibliography - 121 references.

Modern approaches to the design of memory and cognitive function stimulants based on AMPA receptor ligands

Science.gov (United States)

Grigoriev, V. V.; Proshin, A. N.; Kinzirsky, A. S.; Bachurin, Sergey O.

2009-05-01

Data on the structure and properties of compounds acting on AMPA receptors, the key subtype of ionotropic glutamate receptors of the mammalian central nervous system, are analyzed. Data on the role of these receptors in provision of memory and cognitive function formation and impairment processes are presented. The attention is focused on the modern views on the mechanisms of AMPA receptor desensitization and deactivation and action of substances affecting these processes. The structures of key positive modulators of AMPA receptors are given. The problems of application of these substances as therapeutic means for preventing and treating neurodegenerative and psychoneurological diseases are discussed. Bibliography — 121 references.

Characterization of the functional domains of the natriuretic peptide receptor/guanylate cyclase by radiation inactivation

International Nuclear Information System (INIS)

Tremblay, J.; Huot, C.; Koch, C.; Potier, M.

1991-01-01

Radiation inactivation has been used to evaluate the molecular size of domains responsible for atrial natriuretic peptide (ANP)-binding and cyclase functions of the ANP receptor/guanylate cyclase. Two types of inactivation curves were observed for cyclase function in both adrenal cortex and aortic smooth muscle cells: (1) biphasic with enhanced guanylate cyclase activity after exposure to low radiation doses and (2) linear after preincubation of membrane proteins with 0.5 microM ANP or solubilization with Triton X-100. The existence of an inhibitory component was the simplest model that best explained the types of radiation curves obtained. Activation of guanylate cyclase by ANP or Triton X-100 could occur via the dissociation of this inhibitory component from the catalytic domain. On the other hand, the loss of ANP-binding activity was linear with increasing radiation exposures under basal, ANP treatment, and Triton X-100 solubilization conditions. Radiation inactivation sizes of about 30 kDa for cyclase function, 20 kDa for ANP-binding function, and 90 kDa for inhibitory function were calculated. These studies suggest that the ANP receptor/guanylate cyclase behaves as a multidomain protein. The results obtained by radiation inactivation of the various biological functions of this receptor are compatible with the hypothesis of an intramolecular inhibitory domain repressing the guanylate cyclase catalytic domain within its membrane environment

Regulated appearance of NMDA receptor subunits and channel functions during in vitro neuronal differentiation.

Science.gov (United States)

Jelitai, Márta; Schlett, Katalin; Varju, Patrícia; Eisel, Ulrich; Madarász, Emília

2002-04-01

The schedule of NMDA receptor subunit expression and the appearance of functional NMDA-gated ion channels were investigated during the retinoic acid (RA) induced neuronal differentiation of NE-4C, a p53-deficient mouse neuroectodermal progenitor cell line. NR2A, NR2B, and NR2D subunit transcripts were present in both nondifferentiated and neuronally differentiated cultures, while NR2C subunits were expressed only transiently, during the early period of neural differentiation. Several splice variants of NR1 were detected in noninduced progenitors and in RA-induced cells, except the N1 exon containing transcripts that appeared after the fourth day of induction, when neuronal processes were already formed. NR1 and NR2A subunit proteins were detected both in nondifferentiated progenitor cells and in neurons, while the mature form of NR2B subunit protein appeared only at the time of neuronal process elongation. Despite the early presence of NR1 and NR2A subunits, NMDA-evoked responses could be detected in NE-4C neurons only after the sixth day of induction, coinciding in time with the expression of the mature NR2B subunit. The formation of functional NMDA receptors also coincided with the appearance of synapsin I and synaptophysin. The lag period between the production of the subunits and the onset of channel function suggests that subunits capable of channel formation cannot form functional NMDA receptors until a certain stage of neuronal commitment. Thus, the in vitro neurogenesis by NE-4C cells provides a suitable tool to investigate some inherent regulatory processes involved in the initial maturation of NMDA receptor complexes. Copyright 2002 Wiley Periodicals, Inc.

Anomalías de circulación atmosférica en 500 y 1000 hpa asociada a la sequía producida en la Argentina durante enero de 2003 a marzo de 2004 Anomalies of the atmospheric circulation at 500 and 1000 hpa associated with the dry period in Argentina from january 2003 to march 2004

Directory of Open Access Journals (Sweden)

Adelia Perla Alessandro

2008-03-01

Full Text Available Neste trabalho se analisa e descreve a situação sinótica associada à precipitação e temperatura do território argentino durante o ano de 2003 e o primeiro trimestre de 2004. A escolha deste período obedece à falta de precipitações em pelo menos dez províncias argentinas, o que ocasionou grandes prejuízos econômicos no setor agropecuário. Com o intuito de determinar as causas deste déficit de precipitações foram analisados os campos médios de altura geopotencial nos níveis de 500 e 1000 hPa e suas anomalias. Em 2003, o déficit de precipitação se associa principalmente às anomalias de geopotencial no nível de 500 hPa, que mostram um fluxo dominante de SO que atravessa o país diagonalmente entre 45°S e 30°S. Em 1000 hPa o anticiclone subtropical do Atlântico se encontra enfraquecido, deslocado para o norte e afastado do continente, enquanto que o anticiclone subrtopical do Pacífico está mais intenso e deslocado para leste respeito da sua posição normal. No primeiro trimestre de 2004 a seca se deve principalmente à presença de uma crista no nível de 500 hPa posicionada no centro do país. As anomalias médias de temperatura do período considerado resultam positivas sobre toda a Argentina. Em 2003, essas anomalias se devem à contribuição do fluxo do N-NE desde o norte do país, à subsidência ocasionada pelo anticiclone do Pacífico mais deslocado para o interior do continente e a orografia. No primeiro trimestre de 2004 as anomalias se originam devido ao fluxo do norte e à freqüente circulação anticiclônica no Atlântico ao sul de 35°S.This paper analyzes and describes the synoptic situation associated with precipitation and temperature in Argentina during 2003 and the first quarter of 2004. The period was selected as during that time drought affected at least ten Argentine provinces, causing great agricultural and ranching losses. In order to find the causes of such rainfall deficit the mean and

Expression and functional roles of G-protein-coupled estrogen receptor (GPER) in human eosinophils.

Science.gov (United States)

Tamaki, Mami; Konno, Yasunori; Kobayashi, Yoshiki; Takeda, Masahide; Itoga, Masamichi; Moritoki, Yuki; Oyamada, Hajime; Kayaba, Hiroyuki; Chihara, Junichi; Ueki, Shigeharu

2014-07-01

Sexual dimorphism in asthma links the estrogen and allergic immune responses. The function of estrogen was classically believed to be mediated through its nuclear receptors, i.e., estrogen receptors (ERs). However, recent studies established the important roles of G-protein-coupled estrogen receptor (GPER/GPR30) as a novel membrane receptor for estrogen. To date, the role of GPER in allergic inflammation is poorly understood. The purpose of this study was to examine whether GPER might affect the functions of eosinophils, which play an important role in the pathogenesis of asthma. Here, we demonstrated that GPER was expressed in purified human peripheral blood eosinophils both at the mRNA and protein levels. Although GPER agonist G-1 did not induce eosinophil chemotaxis or chemokinesis, preincubation with G-1 enhanced eotaxin (CCL11)-directed eosinophil chemotaxis. G-1 inhibited eosinophil spontaneous apoptosis and caspase-3 activities. The anti-apoptotic effect was not affected by the cAMP-phospodiesterase inhibitor rolipram or phosphoinositide 3-kinase inhibitors. In contrast to resting eosinophils, G-1 induced apoptosis and increased caspase-3 activities when eosinophils were co-stimulated with IL-5. No effect of G-1 was observed on eosinophil degranulation in terms of release of eosinophil-derived neurotoxin (EDN). The current study indicates the functional capacities of GPER on human eosinophils and also provides the previously unrecognized mechanisms of interaction between estrogen and allergic inflammation. Copyright © 2014 Elsevier B.V. All rights reserved.

Cloning and functional characterization of the DA2 receptor gene in Chinese mitten crab (Eriocheir sinensis)

Science.gov (United States)

Xu, Min-jie; Zhang, Cong; Yang, Zhigang

2018-01-01

Dopamine (DA) plays a modulatory role in numerous physiological processes such as light adaptation and food intake, and exerts these functions through DA receptors (DARs). This study presents, for the first time, isolation and characterization of the dopamine receptor 2(DA2 receptor) cDNA from the intestinal tissue of Eriocheir sinensis, an economically important freshwater aquaculture species in China. The DA2 receptor cDNA sequence, which was obtained by rapid amplification of cDNA ends, is 2369bp long, encode peptide of 589 amino acid, and is highly homologous to related sequences in crustaceans. Analysis of the deduced amino acid sequence and the structure of the DA2 indicated that this receptor is a member of the family of G protein-coupled receptors (GPCRs), as it contains seven transmembrane domains and other common signatures of GPCRs. RT-PCR showed that the expression of the DA2 receptor gene was distributed in various tissues, and high expression levels were observed in the cranial ganglia and the thoracic ganglia. Further study of the effect of photoperiod on DA2 expression showed that constant darkness induced a significant increase in DA2 expression in the cranial ganglia. Finally, analysis of DA2 receptor expression under different feeding statuses showed that there was significantly greater expression in the hepatopancreas and intestines after feeding than before feeding, but there were no differences in expression between the before feeding and during feeding periods in either tissue. Our results indicate that the DA2 receptor structurally belongs to the family of G protein-coupled receptors, and that the cranial ganglia are the main tissues in which the DA2 receptor participates in light adaptation during dark hours. In addition, the DA2 receptor in E. sinensis may be involved in the physiological regulation of the hepatopancreas and digestive tract after the ingestion of food. This study provides a foundation for further exploration of the light

Quantification of mutation-derived bias for alternate mating functionalities of the Saccharomyces cerevisiae Ste2p pheromone receptor.

Science.gov (United States)

Choudhary, Pooja; Loewen, Michele C

2016-01-01

Although well documented for mammalian G-protein-coupled receptors, alternate functionalities and associated alternate signalling remain to be unequivocally established for the Saccharomyces cerevisiae pheromone Ste2p receptor. Here, evidence supporting alternate functionalities for Ste2p is re-evaluated, extended and quantified. In particular, strong mating and constitutive signalling mutations, focusing on residues S254, P258 and S259 in TM6 of Ste2p, are stacked and investigated in terms of their effects on classical G-protein-mediated signal transduction associated with cell cycle arrest, and alternatively, their impact on downstream mating projection and zygote formation events. In relative dose response experiments, accounting for systemic and observational bias, mutational-derived functional differences were observed, validating the S254L-derived bias for downstream mating responses and highlighting complex relationships between TM6-mutation derived constitutive signalling and ligand-induced functionalities. Mechanistically, localization studies suggest that alterations to receptor trafficking may contribute to mutational bias, in addition to expected receptor conformational stabilization effects. Overall, these results extend previous observations and quantify the contributions of Ste2p variants to mediating cell cycle arrest versus downstream mating functionalities. © Crown copyright 2015.

Application of 5-hydroxytryptamine receptor imaging for study of neuropsychiatric disorders and brain functions

International Nuclear Information System (INIS)

Qiu Chun; Guan Yihui

2011-01-01

In the central nervous system, the widely distributed 5-hydroxytryptamine (5-HT)receptors are involved in regulating a large number of psychological and physiological functions, including mood, sleep, endocrine and autonomic nervous system. Abnormal 5-HT transmission has been implicated in a variety of neuropsychiatric disorders, such as pain, depression and epilepsy. With the development of radioligands, non-invasive nuclear imaging technique with exquisite sensitivity and specificity has been applied for delineation of neurotransmitter function in vivo. It does great benefit for researches of these diseases and development of drugs. This review provided an overview of 5-HT receptors radioligands and recent findings. (authors)

The phosphatidylserine receptor has essential functions during embryogenesis but not in apoptotic cell removal

Directory of Open Access Journals (Sweden)

Hafner Martin

2004-08-01

Full Text Available Abstract Background Phagocytosis of apoptotic cells is fundamental to animal development, immune function and cellular homeostasis. The phosphatidylserine receptor (Ptdsr on phagocytes has been implicated in the recognition and engulfment of apoptotic cells and in anti-inflammatory signaling. To determine the biological function of the phosphatidylserine receptor in vivo, we inactivated the Ptdsr gene in the mouse. Results Ablation of Ptdsr function in mice causes perinatal lethality, growth retardation and a delay in terminal differentiation of the kidney, intestine, liver and lungs during embryogenesis. Moreover, eye development can be severely disturbed, ranging from defects in retinal differentiation to complete unilateral or bilateral absence of eyes. Ptdsr -/- mice with anophthalmia develop novel lesions, with induction of ectopic retinal-pigmented epithelium in nasal cavities. A comprehensive investigation of apoptotic cell clearance in vivo and in vitro demonstrated that engulfment of apoptotic cells was normal in Ptdsr knockout mice, but Ptdsr-deficient macrophages were impaired in pro- and anti-inflammatory cytokine signaling after stimulation with apoptotic cells or with lipopolysaccharide. Conclusion Ptdsr is essential for the development and differentiation of multiple organs during embryogenesis but not for apoptotic cell removal. Ptdsr may thus have a novel, unexpected developmental function as an important differentiation-promoting gene. Moreover, Ptdsr is not required for apoptotic cell clearance by macrophages but seems to be necessary for the regulation of macrophage cytokine responses. These results clearly contradict the current view that the phosphatidylserine receptor primarily functions in apoptotic cell clearance.

Phosphorylation of SLP-76 by the ZAP-70 protein-tyrosine kinase is required for T-cell receptor function.

Science.gov (United States)

Bubeck Wardenburg, J; Fu, C; Jackman, J K; Flotow, H; Wilkinson, S E; Williams, D H; Johnson, R; Kong, G; Chan, A C; Findell, P R

1996-08-16

Two families of tyrosine kinases, the Src and Syk families, are required for T-cell receptor activation. While the Src kinases are responsible for phosphorylation of receptor-encoded signaling motifs and for up-regulation of ZAP-70 activity, the downstream substrates of ZAP-70 are unknown. Evidence is presented herein that the Src homology 2 (SH2) domain-containing leukocyte protein of 76 kDa (SLP-76) is a substrate of ZAP-70. Phosphorylation of SLP-76 is diminished in T cells that express a catalytically inactive ZAP-70. Moreover, SLP-76 is preferentially phosphorylated by ZAP-70 in vitro and in heterologous cellular systems. In T cells, overexpression of wild-type SLP-76 results in a hyperactive receptor, while expression of a SLP-76 molecule that is unable to be tyrosine-phosphorylated attenuates receptor function. In addition, the SH2 domain of SLP-76 is required for T-cell receptor function, although its role is independent of the ability of SLP-76 to undergo tyrosine phosphorylation. As SLP-76 interacts with both Grb2 and phospholipase C-gamma1, these data indicate that phosphorylation of SLP-76 by ZAP-70 provides an important functional link between the T-cell receptor and activation of ras and calcium pathways.

Combination of behaviorally sub-effective doses of glutamate NMDA and dopamine D1 receptor antagonists impairs executive function.

Science.gov (United States)

Desai, Sagar J; Allman, Brian L; Rajakumar, Nagalingam

2017-04-14

Impairment of executive function is a core feature of schizophrenia. Preclinical studies indicate that injections of either N-methyl d-aspartate (NMDA) or dopamine D 1 receptor blockers impair executive function. Despite the prevailing notion based on postmortem findings in schizophrenia that cortical areas have marked suppression of glutamate and dopamine, recent in vivo imaging studies suggest that abnormalities of these neurotransmitters in living patients may be quite subtle. Thus, we hypothesized that modest impairments in both glutamate and dopamine function can act synergistically to cause executive dysfunction. In the present study, we investigated the effect of combined administration of "behaviorally sub-effective" doses of NMDA and dopamine D 1 receptor antagonists on executive function. An operant conditioning-based set-shifting task was used to assess behavioral flexibility in rats that were systemically injected with NMDA and dopamine D 1 receptor antagonists individually or in combination prior to task performance. Separate injections of the NMDA receptor antagonist, MK-801, and the dopamine D 1 receptor antagonist, SCH 23390, at low doses did not impair set-shifting; however, the combined administration of these same behaviorally sub-effective doses of the antagonists significantly impaired the performance during set-shifting without affecting learning, retrieval of the memory of the initial rule, latency of responses or the number of omissions. The combined treatment also produced an increased number of perseverative errors. Our results indicate that NMDA and D 1 receptor blockade act synergistically to cause behavioral inflexibility, and as such, subtle abnormalities in glutamatergic and dopaminergic systems may act cooperatively to cause deficits in executive function. Copyright © 2017 Elsevier B.V. All rights reserved.

Glucose-6-phosphate dehydrogenase is required for hpa1xoo (harpin protein fragment)-mediated salt stress tolerance in transgenic arabidopsis thaliana

International Nuclear Information System (INIS)

Sang, S.L.; Xie, L.L.; Cui, X.W.; Wang, Z.Y.

2018-01-01

Harpin induces salicylic acid and abscisic acid signaling in plants under biotic and abiotic stress, respectively. Our previous report showed that the effective harpin fragment Hpa1xoo enhanced H2O2 production and pathogen resistance in a transgenic Arabidopsis mutant. In this study, we examined contents of thiobarbituric acid reactive substance (TBARS), H2O2 and glutathione, and glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase (GR) and glutathione peroxidase (GPX) enzyme activity in Hpa1xoo-expressing Arabidopsis under salt stress. The results revealed increased amounts of TBARS and H2O2 in wild-type (WT) compared to mutant plants under salt stress conditions. In contrast, increased levels were observed in the mutant under stress-free conditions. Moreover, a higher reduced glutathione (GSH) content and ratio of GSH/oxidized glutathione (GSSG) was observed in mutant compared to WT plants under both stress-free and salt stress conditions. In addition, mutant plants exhibited significantly higher G6PDH, GR and GPX activity than WT plants under salt stress. Suppression of G6PDH activity via 6-aminonicotinamide (6-AN, a specific inhibitor of G6PDH) was partly reversed by L-buthionine-sulfoximine (BSO, a specific inhibitor of GSH regeneration) and aggravated by GSH. Combined with previous reports, these findings suggest that the G6PDH enzyme plays a key role in harpin fragment (Hpa1xoo)-mediated salt stress tolerance in transgenic Arabidopsis. (author)

The obesity-associated transcription factor ETV5 modulates circulating glucocorticoids

Science.gov (United States)

Gutierrez-Aguilar, Ruth; Thompson, Abigail; Marchand, Nathalie; Dumont, Patrick; Woods, Stephen C.; de Launoit, Yvan; Seeley, Randy J.; Ulrich-Lai, Yvonne M.

2015-01-01

The transcription factor E-twenty-six version 5 (ETV5) has been linked with obesity in genome-wide association studies. Moreover, ETV5-deficient mice (knockout; KO) have reduced body weight, lower fat mass, and are resistant to diet-induced obesity, directly linking ETV5 to the regulation of energy balance and metabolism. ETV5 is expressed in hypothalamic brain regions that regulate both metabolism and HPA axis activity, suggesting that ETV5 may also modulate HPA axis function. In order to test this possibility, plasma corticosterone levels were measured in ETV5 KO and wildtype (WT) mice before (pre-stress) and after (post-stress) a mild stressor (intraperitoneal injection). ETV5 deficiency increased both pre- and post-stress plasma corticosterone, suggesting that loss of ETV5 elevated glucocorticoid tone. Consistent with this idea, ETV5 KO mice have reduced thymus weight, suggestive of increased glucocorticoid-induced thymic involution. ETV5 deficiency also decreased the mRNA expression of glucocorticoid receptor (GR), mineralocorticoid receptor (MR), and vasopressin receptor 1A in the hypothalamus, without altering vasopressin, corticotropin-releasing hormone, or oxytocin mRNA expression. In order to test whether reduced MR and GR expression affected glucocorticoid negative feedback, a dexamethasone suppression test was performed. Dexamethasone reduced plasma corticosterone in both ETV5 KO and WT mice, suggesting that glucocorticoid negative feedback was unaltered by ETV5 deficiency. In summary, these data suggest that the obesity-associated transcription factor ETV5 normally acts to diminish circulating glucocorticoids. This might occur directly via ETV5 actions on HPA-regulatory brain circuitry, and/or indirectly via ETV5-induced alterations in metabolic factors that then influence the HPA axis. PMID:25813907

Association study of molecular polymorphisms in candidate genes related to stress responses with production and meat quality traits in pigs.

Science.gov (United States)

Terenina, E; Babigumira, B M; Le Mignon, G; Bazovkina, D; Rousseau, S; Salin, F; Bendixen, C; Mormede, P

2013-02-01

The hypothalamic-pituitary-adrenal (HPA) axis exerts a large range of effects on metabolism, the immune system, inflammatory processes, and brain functions. Together with the sympathetic nervous system, it is also the most important stress-responsive neuroendocrine system. Both systems influence production traits, carcass composition, and meat quality. The HPA axis may be a critical target for genetic selection of more robust animals. Indeed, numerous studies in various species have demonstrated the importance of genetic factors in shaping the individual HPA axis phenotype, and genetic polymorphism can be found at each level of the axis, including hormone production by the adrenal cortices under stimulation by adrenocorticotropic hormone (ACTH), hormone bioavailability, or receptor and postreceptor mechanisms. The aim of the present experiment was to extend these findings to the brain neurochemical systems involved in stress responses. To this end, a number of candidate genes were sequenced for molecular polymorphisms and their association was studied with stress neuroendocrine and production traits in a genetically diverse population consisting of 100 female pigs from an advanced intercross (F10-F12) between 2 highly divergent breeds, Large White (LW) and Meishan (MS). The LW breed has a high production potential for lean meat and a low HPA axis activity, and the MS breed has low growth rate, fat carcasses-but large litters of highly viable piglets-and a high HPA axis activity. Candidate genes were chosen in the catecholaminergic and serotonergic pathways, in the pituitary control of cortisol production, among genes previously demonstrated to be differentially expressed in ACTH-stimulated adrenal glands from LW and MS pigs, and in cortisol receptors. Sixty new polymorphisms were found. The association study with carcass and meat quality traits and with endocrine traits showed a number of significant results, such as monoamine oxidase (MAOA) polymorphisms with

Toxic stress history and hypothalamic-pituitary-adrenal axis function in a social stress task: Genetic and epigenetic factors.

Science.gov (United States)

Lapp, Hannah E; Ahmed, Sarah; Moore, Celia L; Hunter, Richard G

2018-02-21

Histories of early life stress (ELS) or social discrimination can reach levels of severity characterized as toxic to mental and physical health. Such toxic social stress during development has been linked to altered acute hypothalamic-pituitary-adrenal (HPA) response to social stress in adulthood. However, there are important individual differences in the size and direction of these effects. We explored developmental, genetic, epigenetic, and contextual sources of individual differences in the relationship between ELS, discrimination, and adult responses to acute social stress in a standard laboratory test. Additional measures included perceived status, social support, background activity of HPA axis, and genetic variants in aspects of the stress response system. Participants (n = 90) answered questions about historical and ongoing stress, provided a DNA sample to examine genetic polymorphisms and epigenetic marks, and underwent the Trier Social Stress Test (TSST) during which three saliva samples were collected to assess HPA function. Individuals who reported high levels of childhood adversity had a blunted salivary cortisol response to the TSST. Childhood adversity, discrimination experiences, and FKBP5 genotype were found to predict pretest cortisol levels. Following up on recent observations that the glucocorticoid receptor directly interacts with the mitochondrial genome, particularly the NADH dehydrogenase 6 (MT-ND6) gene, individuals who reported high childhood adversity were also found to have higher percent methylation across six CpG sites upstream of MT-ND6. These findings suggest multiple contributions across psychological, genetic, epigenetic, and social domains to vulnerability and resilience in hypothalamic-pituitary-adrenal axis regulation. Further study to examine how these multiple contributors affect developmental endpoints through integrated or independent pathways will be of use. Copyright © 2018 Elsevier Inc. All rights reserved.

Immunological studies on the structure and function of the nicotinic acetylcholine receptor in mammalian muscle

Energy Technology Data Exchange (ETDEWEB)

Gu, Y.

1989-01-01

The specificity of the antibodies in the serum of a patient with myasthenia gravis for a the {alpha}-bungarotoxin binding sites of the acetylcholine receptor (AChR) was examined using AChRs in the C2 mouse muscle cell line as a model. The antibodies were shown to be specific for one of the two toxin-binding sites. The effect of the antibodies in this myasthenic serum on the functional response of the receptor to cholinergic agonists was also examined using carbamylcholine-induced {sup 22}Na uptake into C2 myotubes as a measured of the receptor function. Antibodies specific for the {gamma}, {delta}, and {epsilon} subunit, respectively, of mammalian muscle AChRs were developed using subunit-specific synthetic peptides as antigens. Using these antibodies and monoclonal antibodies for other subunits as probes, I have identified four ({alpha}, {beta}, {gamma}, and {delta}) subunits of mammalian muscle AChRs on immunoblots. When AChRs from embryonic, neonatal, normal and denervated adult muscles were compared on immunoblots, the {alpha}, {beta}, and {delta} subunits were identical in all four receptor preparations, with or without endoglycosidase digestion. The spatial and temporal distribution of the {gamma}- and {epsilon}- AChRs in developing and in denervated muscles corresponds to the distribution of AChRs with slow and fast channels, respectively, and that the development changes in the channel properties of the receptor arise from a change in the subunit composition of the receptor, in which the {gamma} is replaced by {epsilon}.

Immunological studies on the structure and function of the nicotinic acetylcholine receptor in mammalian muscle

International Nuclear Information System (INIS)

Gu, Y.

1989-01-01

The specificity of the antibodies in the serum of a patient with myasthenia gravis for a the α-bungarotoxin binding sites of the acetylcholine receptor (AChR) was examined using AChRs in the C2 mouse muscle cell line as a model. The antibodies were shown to be specific for one of the two toxin-binding sites. The effect of the antibodies in this myasthenic serum on the functional response of the receptor to cholinergic agonists was also examined using carbamylcholine-induced 22 Na uptake into C2 myotubes as a measured of the receptor function. Antibodies specific for the γ, δ, and ε subunit, respectively, of mammalian muscle AChRs were developed using subunit-specific synthetic peptides as antigens. Using these antibodies and monoclonal antibodies for other subunits as probes, I have identified four (α, β, γ, and δ) subunits of mammalian muscle AChRs on immunoblots. When AChRs from embryonic, neonatal, normal and denervated adult muscles were compared on immunoblots, the α, β, and δ subunits were identical in all four receptor preparations, with or without endoglycosidase digestion. The spatial and temporal distribution of the γ- and ε- AChRs in developing and in denervated muscles corresponds to the distribution of AChRs with slow and fast channels, respectively, and that the development changes in the channel properties of the receptor arise from a change in the subunit composition of the receptor, in which the γ is replaced by ε

The Environmental Pollutant Tributyltin Chloride Disrupts the Hypothalamic-Pituitary-Adrenal Axis at Different Levels in Female Rats.

Science.gov (United States)

Merlo, Eduardo; Podratz, Priscila L; Sena, Gabriela C; de Araújo, Julia F P; Lima, Leandro C F; Alves, Izabela S S; Gama-de-Souza, Letícia N; Pelição, Renan; Rodrigues, Lívia C M; Brandão, Poliane A A; Carneiro, Maria T W D; Pires, Rita G W; Martins-Silva, Cristina; Alarcon, Tamara A; Miranda-Alves, Leandro; Silva, Ian V; Graceli, Jones B

2016-08-01

Tributyltin chloride (TBT) is an environmental contaminant that is used as a biocide in antifouling paints. TBT has been shown to induce endocrine-disrupting effects. However, studies evaluating the effects of TBT on the hypothalamus-pituitary-adrenal (HPA) axis are especially rare. The current study demonstrates that exposure to TBT is critically responsible for the improper function of the mammalian HPA axis as well as the development of abnormal morphophysiology in the pituitary and adrenal glands. Female rats were treated with TBT, and their HPA axis morphophysiology was assessed. High CRH and low ACTH expression and high plasma corticosterone levels were detected in TBT rats. In addition, TBT leads to an increased in the inducible nitric oxide synthase protein expression in the hypothalamus of TBT rats. Morphophysiological abnormalities, including increases in inflammation, a disrupted cellular redox balance, apoptosis, and collagen deposition in the pituitary and adrenal glands, were observed in TBT rats. Increases in adiposity and peroxisome proliferator-activated receptor-γ protein expression in the adrenal gland were observed in TBT rats. Together, these data provide in vivo evidence that TBT leads to functional dissociation between CRH, ACTH, and costicosterone, which could be associated an inflammation and increased of inducible nitric oxide synthase expression in hypothalamus. Thus, TBT exerts toxic effects at different levels on the HPA axis function.

The acute effect of a mineralocorticoid receptor agonist on corticotrope secretion in Addison's disease.

Science.gov (United States)

Berardelli, R; Karamouzis, I; D'Angelo, V; Fussotto, B; Minetto, M A; Ghigo, E; Giordano, R; Arvat, E

2016-05-01

Mineralocorticoid receptors (MR) in the hippocampus display an important role in the control of hypothalamic-pituitary-adrenal (HPA) axis, mediating the ''proactive'' feedback of glucocorticoids (GC). Fludrocortisone (FC), a potent MR agonist, has been shown to decrease HPA activity through a hippocampal mechanism. Since it has been demonstrated that FC shows a significant inhibition of the HPA axis response to hCRH stimulus in normal subjects, also at doses usually administered as replacement therapy in patients with Addison's disease, an FC effect at MRs in human pituitary or a GR-pituitary agonism stronger than believed until now has been postulated. Ten patients affected by autoimmune Addison's disease received: (1) placebo p.o. + placebo i.v., (2) hydrocortisone (H) 10 mg p.o. + placebo i.v., (3) FC 0.1 mg p.o. + placebo i.v., (4) FC 0.1 mg and H 10 mg p.o. + placebo i.v. to verify a possible GR FC-mediated effect that might display a repercussion on the GC-replacement therapy. H reduced ACTH (p < 0.01) and increased cortisol levels (p < 0.01) with respect to the placebo session, while FC did not affect either ACTH or cortisol levels compared to placebo, and higher ACTH and lower cortisol levels (p < 0.03 and p < 0.01) were observed compared with the H session; furthermore the co-administration of FC + H showed ACTH and cortisol profiles similar to that observed during H alone. Our study showed a lack of FC effect on corticotrope secretion in Addison's disease, thus making unlikely the hypothesis of its GR pituitary agonism and the risk of glucocorticoid excess in primary adrenal insufficiency.

Investigation of serotonin-1A receptor function in the human psychopharmacology of MDMA.

Science.gov (United States)

Hasler, F; Studerus, E; Lindner, K; Ludewig, S; Vollenweider, F X

2009-11-01

Serotonin (5-HT) release is the primary pharmacological mechanism of 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') action in the primate brain. Dopamine release and direct stimulation of dopamine D2 and serotonin 5-HT2A receptors also contributes to the overall action of MDMA. The role of 5-HT1A receptors in the human psychopharmacology of MDMA, however, has not yet been elucidated. In order to reveal the consequences of manipulation at the 5-HT1A receptor system on cognitive and subjective effects of MDMA, a receptor blocking study using the mixed beta-adrenoreceptor blocker/5-HT1A antagonist pindolol was performed. Using a double-blind, placebo-controlled within-subject design, 15 healthy male subjects were examined under placebo (PL), 20 mg pindolol (PIN), MDMA (1.6 mg/kg b.wt.), MDMA following pre-treatment with pindolol (PIN-MDMA). Tasks from the Cambridge Neuropsychological Test Automated Battery were used for the assessment of cognitive performance. Psychometric questionnaires were applied to measure effects of treatment on core dimensions of Altered States of Consciousness, mood and state anxiety. Compared with PL, MDMA significantly impaired sustained attention and visual-spatial memory, but did not affect executive functions. Pre-treatment with PIN did not significantly alter MDMA-induced impairment of cognitive performance and only exerted a minor modulating effect on two psychometric scales affected by MDMA treatment ('positive derealization' and 'dreaminess'). Our findings suggest that MDMA differentially affects higher cognitive functions, but does not support the hypothesis from animal studies, that some of the MDMA effects are causally mediated through action at the 5-HT1A receptor system.

Stress reactivity in childhood functional abdominal pain or irritable bowel syndrome.

Science.gov (United States)

Gulewitsch, M D; Weimer, K; Enck, P; Schwille-Kiuntke, J; Hautzinger, M; Schlarb, A A

2017-01-01

Frequent abdominal pain (AP) in childhood has been shown to be associated with elevated experience of stress and with deficits in stress coping, but psychophysiological stress reactivity has been studied rarely. We examined whether children with frequent AP show altered reactions of the parasympathetic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis during and following an afternoon laboratory social stress task in comparison to healthy children and children with anxiety disorders. Twenty-four children with frequent AP (18 with functional AP and six with irritable bowel syndrome; M = 9.9 years), and 24 healthy controls underwent stressful free speech and arithmetic tasks. Twelve children with anxiety disorders served as second comparison sample. Groups were compared regarding parasympathetic reaction and saliva cortisol concentration. We found no differences in parasympathetic withdrawal between the groups. Concerning the HPA axis, we detected an attenuated cortisol reactivity in children with AP compared to both other groups. This study provides preliminary evidence that childhood AP is not associated with altered parasympathetic withdrawal during stress. It seems to be related to a down-regulated reactivity of the HPA axis. This pattern was ascertained in comparison to healthy children and also in comparison to children with anxiety disorders. Childhood abdominal pain could be related to down-regulated HPA axis reactivity to stress but not to altered parasympathetic reaction. Children with abdominal pain and children with anxiety disorders exhibit a divergent stress-related HPA axis reaction. © 2016 European Pain Federation - EFIC®.

Does stress affect the joints? Daily stressors, stress vulnerability, immune and HPA axis activity, and short-term disease and symptom fluctuations in rheumatoid arthritis.

Science.gov (United States)

Evers, Andrea W M; Verhoeven, Elisabeth W M; van Middendorp, Henriët; Sweep, Fred C G J; Kraaimaat, Floris W; Donders, A Rogier T; Eijsbouts, Agnes E; van Laarhoven, Antoinette I M; de Brouwer, Sabine J M; Wirken, Lieke; Radstake, Timothy R D J; van Riel, Piet L C M

2014-09-01

Both stressors and stress vulnerability factors together with immune and hypothalamus-pituitary-adrenal (HPA) axis activity components have been considered to contribute to disease fluctuations of chronic inflammatory diseases, such as rheumatoid arthritis (RA). The aim of the present study was to investigate whether daily stressors and worrying as stress vulnerability factor as well as immune and HPA axis activity markers predict short-term disease activity and symptom fluctuations in patients with RA. In a prospective design, daily stressors, worrying, HPA axis (cortisol) and immune system (interleukin (IL)-1β, IL-6, IL-8, interferon (IFN)-γ, tumour necrosis factor α) markers, clinical and self-reported disease activity (disease activity score in 28 joints, RA disease activity index), and physical symptoms of pain and fatigue were monitored monthly during 6 months in 80 RA patients. Multilevel modelling indicated that daily stressors predicted increased fatigue in the next month and that worrying predicted increased self-reported disease activity, swollen joint count and pain in the next month. In addition, specific cytokines of IL-1β and IFN-γ predicted increased fatigue 1 month later. Overall, relationships remained relatively unchanged after controlling for medication use, disease duration and demographic variables. No evidence was found for immune and HPA axis activity markers as mediators of the stress-disease relationship. Daily stressors and the stress-vulnerability factor worrying predict indicators of the short-term course of RA disease activity and fatigue and pain, while specific cytokines predict short-term fluctuations of fatigue. These stress-related variables and immune markers seem to affect different aspects of disease activity or symptom fluctuations independently in RA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Pathophysiological consequences of receptor mistraffic: Tales from the platelet P2Y12 receptor.

Science.gov (United States)

Cunningham, Margaret R; Aungraheeta, Riyaad; Mundell, Stuart J

2017-07-05

Genetic variations in G protein-coupled receptor (GPCR) genes can disrupt receptor function in a wide variety of human genetic diseases, including platelet bleeding disorders. Platelets are critical for haemostasis with inappropriate platelet activation leading to the development of arterial thrombosis, which can result in heart attack and stroke whilst decreased platelet activity is associated with an increased risk of bleeding. GPCRs expressed on the surface of platelets play key roles in regulating platelet activity and therefore function. Receptors include purinergic receptors (P2Y 1 and P2Y 12 ), proteinase-activated receptor (PAR1 and PAR4) and thromboxane receptors (TPα), among others. Pharmacological blockade of these receptors forms a powerful therapeutic tool in the treatment and prevention of arterial thrombosis. With the advance of genomic technologies, there has been a substantial increase in the identification of naturally occurring rare and common GPCR variants. These variants include single-nucleotide polymorphisms (SNPs) and insertion or deletions that have the potential to alter GPCR expression or function. A number of defects in platelet GPCRs that disrupt receptor function have now been characterized in patients with mild bleeding disorders. This review will focus on rare, function-disrupting variants of platelet GPCRs with particular emphasis upon mutations in the P2Y 12 receptor gene that affect receptor traffic to modulate platelet function. Further this review will outline how the identification and characterization of function-disrupting GPCR mutations provides an essential link in translating our detailed understanding of receptor traffic and function in cell line studies into relevant human biological systems. Copyright © 2017. Published by Elsevier B.V.

HPA-axis hyperactivity and mortality in psychotic depressive disorder: preliminary findings.

Science.gov (United States)

Coryell, William; Fiedorowicz, Jess; Zimmerman, Mark; Young, Elizabeth

2008-06-01

The excess mortality associated with depressive disorders has been most often attributed to risks for suicide but diverse findings indicate that depressive disorders also increase risks for cardiovascular (CV) mortality. Among the possible mediators is the hypothalamic-pituitary-adrenal (HPA)-axis hyperactivity that characterizes many cases of relatively severe depressive disorder and severity is characteristic of psychotic depressive disorder. The following describes a 17-year mortality follow-up of 54 patients with Research Diagnostic Criteria (RDC) psychotic major depression or schizoaffective, mainly affective, depression. All had baseline assessments that included a 1mg dexamethasone suppression test with post-dexamethasone samples at 8 a.m., 4 p.m. and 11 p.m. Regression analyses showed that both greater age and higher maximum post-dexamethasone cortisol concentrations predicted deaths due to CV causes (t=4.01, pdepressive disorder to CV mortality.

Two-year stability of individual differences in (para)sympathetic and HPA-axis responses to public speaking in childhood and adolescence.

Science.gov (United States)

van den Bos, Esther; Westenberg, P Michiel

2015-03-01

Long-term stability of individual differences in stress responses has repeatedly been demonstrated in adults, but few studies have investigated the development of stability in adolescence. The present study was the first to investigate the stability of individual differences in heart rate, parasympathetic (RMSSD, pNN50, HF), sympathetic (LF/HF, SC), and HPA-axis (salivary cortisol) responses in a youth sample (8-19 years). Responses to public speaking were measured twice over 2 years. Stability was moderate for absolute responses and task delta responses of HR, RMSSD, pNN50, and HF. Stability was lower for SC and task delta responses of LF/HF and cortisol. Anticipation delta responses showed low stability for HR and cortisol. The latter was moderated by age or puberty, so that individual differences were more stable in more mature individuals. The results support the suggestion that stress responses may be reset during adolescence, but only for the HPA axis. © 2014 Society for Psychophysiological Research.

Rapid resensitization of purinergic receptor function in human platelets.

Science.gov (United States)

Mundell, S J; Barton, J F; Mayo-Martin, M B; Hardy, A R; Poole, A W

2008-08-01

Adenosine diphosphate (ADP) is a critical regulator of platelet activation, mediating its actions through two G protein-coupled receptors (GPCRs), the P2Y(1) and P2Y(12) purinergic receptors. Recently, we demonstrated that both receptors desensitize and internalize in human platelets by differential kinase-dependent mechanisms. To demonstrate whether responses to P2Y(1) and P2Y(12) purinergic receptors resensitize in human platelets and determine the role of receptor traffic in this process. These studies were undertaken either in human platelets or in cells stably expressing epitope-tagged P2Y(1) and P2Y(12) purinergic receptor constructs. In this study we show for the first time that responses to both of these receptors can rapidly resensitize following agonist-dependent desensitization in human platelets. Further, we show that in human platelets or in 1321N1 cells stably expressing receptor constructs, the disruption of receptor internalization, dephosphorylation or subsequent receptor recycling is sufficient to block resensitization of purinergic receptor responses. We also show that, in platelets, internalization of both these receptors is dependent upon dynamin, and that this process is required for resensitization of responses. This study is therefore the first to show that both P2Y(1) and P2Y(12) receptor activities are rapidly and reversibly modulated in human platelets, and it reveals that the underlying mechanism requires receptor trafficking as an essential part of this process.

Developmental and contextual considerations for adrenal and gonadal hormone functioning during adolescence: Implications for adolescent mental health.

Science.gov (United States)

Marceau, Kristine; Ruttle, Paula L; Shirtcliff, Elizabeth A; Essex, Marilyn J; Susman, Elizabeth J

2015-09-01

Substantial research has implicated the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes independently in adolescent mental health problems, though this literature remains largely inconclusive. Given the cross-talk between the HPA and HPG axes and their increased activation in adolescence, a dual-axis approach that examines both axes simultaneously is proposed to predict the emergence and persistence of adolescent mental health problems. After briefly orienting readers to HPA and HPG axis functioning, we review the literature examining associations between hormone levels and changes with behavior during adolescence. Then, we provide a review of the literature supporting examination of both axes simultaneously and present the limited research that has taken a dual-axis approach. We propose future directions including consideration of between-person and within-person approaches to address questions of correlated changes in HPA and HPG hormones. Potential moderators are considered to increase understanding of the nuanced hormone-behavior associations during key developmental transitions. © 2014 Wiley Periodicals, Inc.

Anatomy of melancholia: focus on hypothalamic-pituitary-adrenal axis overactivity and the role of vasopressin.

LENUS (Irish Health Repository)

Dinan, Timothy G

2012-02-03

Overactivity of the hypothalamic-pituitary-adrenal (HPA) axis characterized by hypercortisolism, adrenal hyperplasia and abnormalities in negative feedback is the most consistently described biological abnormality in melancholic depression. Corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) are the main secretagogues of the HPA\\/stress system. Produced in the parvicellular division of the hypothalamic paraventricular nucleus the release of these peptides is influenced by inputs from monoaminergic neurones. In depression, anterior pituitary CRH1 receptors are down-regulated and response to CRH infusion is blunted. By contrast, vasopressin V3 receptors on the anterior pituitary show enhanced response to AVP stimulation and this enhancement plays a key role in maintaining HPA overactivity.

HPA-axis stress reactivity in youth depression: evidence of impaired regulatory processes in depressed boys.

Science.gov (United States)

Lopez-Duran, Nestor L; McGinnis, Ellen; Kuhlman, Kate; Geiss, Elisa; Vargas, Ivan; Mayer, Stefanie

2015-01-01

Given the link between youth depression and stress exposure, efforts to identify related biomarkers have involved examinations of stress regulation systems, including the hypothalamic-pituitary-adrenal (HPA) axis. Despite these vast efforts, the underlying mechanisms at play, as well as factors that may explain heterogeneity of past findings, are not well understood. In this study, we simultaneously examined separate components of the HPA-axis response (e.g. activation intensity, peak levels, recovery) to the Socially Evaluated Cold-Pressor Test in a targeted sample of 115 youth (age 9-16), recruited to overrepresent youth with elevated symptoms of depression. Among youth who displayed a cortisol response to the task, depression symptoms were associated with higher peak responses but not greater rate of activation or recovery in boys only. Among those who did not respond to the task, depression symptoms were associated with greater cortisol levels throughout the visit in boys and girls. Results suggest that depression symptoms are associated with a more prolonged activation of the axis and impaired recovery to psychosocial stressors primarily in boys. We discussed two potential mechanistic explanations of the link between depression symptoms and the duration of activation: (1) inhibitory shift (i.e. point at which the ratio of inhibitory and excitatory input into the axis shifts from greater excitatory to greater inhibitory input) or (2) inhibitory threshold (i.e. level of cortisol exposure required to activate the axis' feedback inhibition system).

The Role of TAM Family Receptors in Immune Cell Function: Implications for Cancer Therapy.

Science.gov (United States)

Paolino, Magdalena; Penninger, Josef M

2016-10-21

The TAM receptor protein tyrosine kinases-Tyro3, Axl, and Mer-are essential regulators of immune homeostasis. Guided by their cognate ligands Growth arrest-specific gene 6 (Gas6) and Protein S (Pros1), these receptors ensure the resolution of inflammation by dampening the activation of innate cells as well as by restoring tissue function through promotion of tissue repair and clearance of apoptotic cells. Their central role as negative immune regulators is highlighted by the fact that deregulation of TAM signaling has been linked to the pathogenesis of autoimmune, inflammatory, and infectious diseases. Importantly, TAM receptors have also been associated with cancer development and progression. In a cancer setting, TAM receptors have a dual regulatory role, controlling the initiation and progression of tumor development and, at the same time, the associated anti-tumor responses of diverse immune cells. Thus, modulation of TAM receptors has emerged as a potential novel strategy for cancer treatment. In this review, we discuss our current understanding of how TAM receptors control immunity, with a particular focus on the regulation of anti-tumor responses and its implications for cancer immunotherapy.

S1P receptor signalling and RGS proteins; expression and function in vascular smooth muscle cells and transfected CHO cells

NARCIS (Netherlands)

Hendriks-Balk, Mariëlle C.; van Loenen, Pieter B.; Hajji, Najat; Michel, Martin C.; Peters, Stephan L. M.; Alewijnse, Astrid E.

2009-01-01

Sphingosine-1-phosphate (S1P) signalling via G protein-coupled receptors is important for the regulation of cell function and differentiation. Specific Regulators of G protein Signalling (RGS) proteins modulate the function of these receptors in many cell types including vascular smooth muscle cells

Regulation of β2-adrenergic receptor function by conformationally selective single-domain intrabodies

DEFF Research Database (Denmark)

Staus, Dean P; Wingler, Laura M; Strachan, Ryan T

2014-01-01

. However, a monomeric single-domain antibody (nanobody) from the Camelid family was recently found to allosterically bind and stabilize an active conformation of the β2-adrenergic receptor (β2AR). Here, we set out to study the functional interaction of 18 related nanobodies with the β2AR to investigate...... their roles as novel tools for studying GPCR biology. Our studies revealed several sequence-related nanobody families with preferences for active (agonist-occupied) or inactive (antagonist-occupied) receptors. Flow cytometry analysis indicates that all nanobodies bind to epitopes displayed...... on the intracellular receptor surface; therefore, we transiently expressed them intracellularly as "intrabodies" to test their effects on β2AR-dependent signaling. Conformational specificity was preserved after intrabody conversion as demonstrated by the ability for the intracellularly expressed nanobodies...

Functional characterisation of the human alpha1 glycine receptor in a fluorescence-based membrane potential assay

DEFF Research Database (Denmark)

Jensen, Anders A.; Kristiansen, Uffe

2004-01-01

In the present study, we have created a stable HEK293 cell line expressing the human homomeric alpha1 glycine receptor (GlyR) and characterised its functional pharmacology in a conventional patch-clamp assay and in the FLIPR Membrane Potential (FMP) assay, a fluorescence-based high throughput scr...... not be suited for sophisticated studies of GlyR pharmacology and kinetics. However, the assay offers several advantages in studies of ligand-receptor interactions. Furthermore, the assay could be highly useful in the search for structurally novel ligands acting at GlyRs.......In the present study, we have created a stable HEK293 cell line expressing the human homomeric alpha1 glycine receptor (GlyR) and characterised its functional pharmacology in a conventional patch-clamp assay and in the FLIPR Membrane Potential (FMP) assay, a fluorescence-based high throughput...... ion did not appear to potentiate GlyR function at lower concentrations. Analogously, whereas pregnenolone sulphate inhibited alpha1 GlyR function, the potentiation of alpha1 GlyR by pregnenolone in electrophysiological studies could not be reproduced in the assay. In conclusion, the FMP assay may...

Multiple functions and essential roles of nuclear receptor coactivators of bHLH-PAS family.

Science.gov (United States)

Pecenova, L; Farkas, Robert

2016-07-01

Classical non-peptide hormones, such as steroids, retinoids, thyroid hormones, vitamin D3 and their derivatives including prostaglandins, benzoates, oxysterols, and bile acids, are collectively designated as small lipophilic ligands, acting via binding to the nuclear receptors (NRs). The NRs form a large superfamily of transcription factors that participate virtually in every key biological process. They control various aspects of animal development, fertility, gametogenesis, and numerous metabolic pathways, and can be misregulated in many types of cancers. Their enormous functional plasticity, as transcription factors, relates in part to NR-mediated interactions with plethora of coregulatory proteins upon ligand binding to their ligand binding domains (LBD), or following covalent modification. Here, we review some general views of a specific group of NR coregulators, so-called nuclear receptor coactivators (NRCs) or steroid receptor coactivators (SRCs) and highlight some of their unique functions/roles, which are less extensively mentioned and discussed in other reviews. We also try to pinpoint few neglected moments in the cooperative action of SRCs, which may also indicate their variable roles in the hormone-independent signaling pathways.

[The hypothalamic-pituitary-adrenal axis and depressive disorder: recent progress].

Science.gov (United States)

Kunugi, Hiroshi; Hori, Hiroaki; Numakawa, Tadahiro; Ota, Miho

2012-08-01

Depression is a stress-induced disorder and there is compelling evidence for the involvement of hypothalamic-pituitary-adrenal (HPA) axis abnormalities in the disease. Chronic hyperactivity of the HPA axis and resultant excessive glucocorticoid (hypercortisolism) may be causal to depression. We demonstrated that the dexamethasone (DEX)/CRH test is a sensitive state-dependent marker to monitor HPA axis abnormalities. Restoration from HPA axis abnormalities occurs with clinical responses to treatment. Brain-derived neurotrophic factor (BDNF) has also been implicated in depression. We found that glucocorticoid (DEX) suppresses BDNF-induced dendrite outgrowth and synaptic formation via blocking the MAPK pathway in early-developing cultured hippocampal neurons. Furthermore, we demonstrated that glucocorticoid receptor (GR) and TrkB (a specific receptor of BDNF) interact and that DEX acutely suppresses BDNF-induced glutamate release by affecting the PLC-gamma pathway in cultured cortical neurons, indicating a mechanism underlying the effect of excessive glucocorticoid on BDNF function and resultant damage in cortical neurons. In a macroscopic view using magnetic resonance imaging (MRI), we found that individuals with hypercortisolism detected by the DEX/CRH test demonstrated volume loss in gray matter and reduced neural network assessed with diffusion tensor imaging in several brain regions. Finally, we observed that individuals with hypocortisolism detected by the DEX/CRH test tend to present more distress symptoms, maladaptive coping styles, and schizotypal personality traits than their counterparts, which points to the important role of hypocortisolism as well as hypercortisolism in depression spectrum disorders.

Antidepressant-like effects of salidroside on olfactory bulbectomy-induced pro-inflammatory cytokine production and hyperactivity of HPA axis in rats.

Science.gov (United States)

Yang, Shui-Jin; Yu, Hai-Yang; Kang, Dan-Yu; Ma, Zhan-Qiang; Qu, Rong; Fu, Qiang; Ma, Shi-Ping

2014-09-01

Salidroside (SA) is the primary bioactive marker compound in the standardized extracts from Rhodiola rosea. Although it has potential antidepressant activity in a rat behavioral despair model, the mechanisms of antidepressant effect for SA remain unclear. The objective of this study was to evaluate the antidepressant effects of SA and to discuss the potential mechanisms in olfactory bulbectomized (OBX) rats. SA of 20, 40 mg/kg (p.o.) for 2 weeks notably alleviated OBX-induced hyperactivity in open field test, decreased immobility time in TST and FST. Chronic treatment with SA could remarkably reduce TNF-α and IL-1β levels in hippocampus. Western blot showed that SA could markedly increase glucocorticoid receptor (GR) and brain-derived neurotrophic factor (BDNF) expression in the hippocampus. Besides, SA could also attenuate corticotropin-releasing hormone (CRH) expression in hypothalamus, as well as reducing significantly the levels of serum corticosterone. In conclusion, this study demonstrated that OBX rats treated with SA could significantly improve the depressive-like behaviors. The antidepressant mechanisms of SA might be associated with its anti-inflammatory effects and the regulation of HPA axis activity. Reversal of abnormalities of GR may be partly responsible for those effects. These findings suggested that SA might become a beneficial agent to prevent and treat the depression. Copyright © 2014 Elsevier Inc. All rights reserved.

Expression of functional toll-like receptor-2 and -4 on alveolar epithelial cells.

Science.gov (United States)

Armstrong, Lynne; Medford, Andrew R L; Uppington, Kay M; Robertson, John; Witherden, Ian R; Tetley, Teresa D; Millar, Ann B

2004-08-01

The recognition of potentially harmful microorganisms involves the specific recognition of pathogen-associated molecular patterns (PAMPs) and the family of Toll-like receptors (TLRs) is known to play a central role in this process. TLR-4 is the major recognition receptor for lipopolysaccharide (LPS), a component of gram-negative bacterial cell walls, whereas TLR-2 responds to bacterial products from gram-positive organisms. Although resident alveolar macrophages are the first line of defense against microbial attack, it is now understood that the alveolar epithelium also plays a pivotal role in the innate immunity of the lung. The purpose of the current study was to determine whether human primary type II alveolar epithelial cells (ATII) express functional TLR-2 and TLR-4 and how they may be regulated by inflammatory mediators. We have used reverse transcriptase-polymerase chain reaction and flow cytometry to determine basal and inducible expression on ATII. We have used highly purified preparations of the gram-positive bacterial product lipoteichoic acid (LTA) and LPS to look at the functional consequences of TLR-2 and TLR-4 ligation, respectively, in terms of interleukin-8 release. We have shown that human primary ATII cells express mRNA and protein for both TLR-2 and TLR-4, which can be modulated by incubation with LPS and tumor necrosis factor. Furthermore, we have demonstrated that these receptors are functional. This suggests that ATII have the potential to contribute significantly to the host defense of the human alveolus against bacteria.

A novel mutation in the P2Y12 receptor and a function-reducing polymorphism in protease-activated receptor 1 in a patient with chronic bleeding.

Science.gov (United States)

Patel, Y M; Lordkipanidzé, M; Lowe, G C; Nisar, S P; Garner, K; Stockley, J; Daly, M E; Mitchell, M; Watson, S P; Austin, S K; Mundell, S J

2014-05-01

The study of patients with bleeding problems is a powerful approach in determining the function and regulation of important proteins in human platelets. We have identified a patient with a chronic bleeding disorder expressing a homozygous P2RY(12) mutation, predicting an arginine to cysteine (R122C) substitution in the G-protein-coupled P2Y(12) receptor. This mutation is found within the DRY motif, which is a highly conserved region in G-protein-coupled receptors (GPCRs) that is speculated to play a critical role in regulating receptor conformational states. To determine the functional consequences of the R122C substitution for P2Y(12) function. We performed a detailed phenotypic analysis of an index case and affected family members. An analysis of the variant R122C P2Y(12) stably expressed in cells was also performed. ADP-stimulated platelet aggregation was reduced as a result of a significant impairment of P2Y(12) activity in the patient and family members. Cell surface R122C P2Y(12) expression was reduced both in cell lines and in platelets; in cell lines, this was as a consequence of agonist-independent internalization followed by subsequent receptor trafficking to lysosomes. Strikingly, members of this family also showed reduced thrombin-induced platelet activation, owing to an intronic polymorphism in the F2R gene, which encodes protease-activated receptor 1 (PAR-1), that has been shown to be associated with reduced PAR-1 receptor activity. Our study is the first to demonstrate a patient with deficits in two stimulatory GPCR pathways that regulate platelet activity, further indicating that bleeding disorders constitute a complex trait. © 2014 International Society on Thrombosis and Haemostasis.