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Sample records for histamine receptors coupled

  1. Histamine and Histamine Receptors in Allergic Dermatitis.

    Science.gov (United States)

    Ohtsu, Hiroshi; Seike, Masahiro

    2017-01-01

    In this chapter we will first introduce the pathophysiological process of several skin diseases including allergic dermatitis, a common skin disease, including chronic allergic contact dermatitis (CACD), and atopic dermatitis (AD). In CACD and AD patients, repeated skin exposure to antigens contributes to the development of chronic eczematous lesions. Repeated application of haptens on mice allows emulation of the development of CACD in humans. Further, we will focus on H1, H2, and H4 histamine receptors and their effects on CACD and AD. Histamine-deficient mice, with a knockout histidine decarboxylase (HDC) gene, were used to investigate the role of histamine in CACD and AD. Histamine induces infiltration of inflammatory cells, including mast cells and eosinophils, and elevates Th2 cytokine levels in CACD. Histamine promotes the development of eczematous lesions, elevates IgE serum levels, and induces scratching behavior in CACD. The administration of H1 or H4 receptor antagonists was effective to ameliorate these symptoms in murine CACD models. The combination of H1 and H4 receptor antagonists is a potential therapeutic target for chronic inflammatory skin diseases such as CACD and AD, since combined therapy proved to be more effective than monotherapy.

  2. Histamine, histamine receptors and antihistamines: new concepts.

    Science.gov (United States)

    Criado, Paulo Ricardo; Criado, Roberta Fachini Jardim; Maruta, Celina W; Machado Filho, Carlos d'Apparecida

    2010-01-01

    Drugs with antihistamine action are the most commonly prescribed medication in daily dermatologic practice, both to adults and children. This article addresses new concepts of the role of histamine receptors (H1 receptors) and discusses the anti-inflammatory effects of these drugs. Second generation antihistamines differs from first generation because of their high specificity and affinity for peripheral H1-receptors. Second generation antihistamines are also less likely to produce sedation because they have less effect on the central nervous system. Although the efficacy of the various H1-antihistamines in the treatment of allergic patients is similar, even when comparing first- and second-generation drugs, these drugs are still very different in terms of their chemical structure, pharmacology and toxic properties. Consequently, knowledge of their pharmacokinetic and pharmacodynamic characteristics is essential for a better medical care, especially that offered to pregnant women, children, the elderly, and patients with comorbidities.

  3. The Target Residence Time of Antihistamines Determines Their Antagonism of the G Protein-Coupled Histamine H1 Receptor.

    Science.gov (United States)

    Bosma, Reggie; Witt, Gesa; Vaas, Lea A I; Josimovic, Ivana; Gribbon, Philip; Vischer, Henry F; Gul, Sheraz; Leurs, Rob

    2017-01-01

    The pharmacodynamics of drug-candidates is often optimized by metrics that describe target binding (Kd or Ki value) or target modulation (IC50). However, these metrics are determined at equilibrium conditions, and consequently information regarding the onset and offset of target engagement and modulation is lost. Drug-target residence time is a measure for the lifetime of the drug-target complex, which has recently been receiving considerable interest, as target residence time is shown to have prognostic value for the in vivo efficacy of several drugs. In this study, we have investigated the relation between the increased residence time of antihistamines at the histamine H1 receptor (H1R) and the duration of effective target-inhibition by these antagonists. Hela cells, endogenously expressing low levels of the H1R, were incubated with a series of antihistamines and dissociation was initiated by washing away the unbound antihistamines. Using a calcium-sensitive fluorescent dye and a label free, dynamic mass redistribution based assay, functional recovery of the H1R responsiveness was measured by stimulating the cells with histamine over time, and the recovery was quantified as the receptor recovery time. Using these assays, we determined that the receptor recovery time for a set of antihistamines differed more than 40-fold and was highly correlated to their H1R residence times, as determined with competitive radioligand binding experiments to the H1R in a cell homogenate. Thus, the receptor recovery time is proposed as a cell-based and physiologically relevant metric for the lead optimization of G protein-coupled receptor antagonists, like the H1R antagonists. Both, label-free or real-time, classical signaling assays allow an efficient and physiologically relevant determination of kinetic properties of drug molecules.

  4. Endogenous expression of histamine H1 receptors functionally coupled to phosphoinositide hydrolysis in C6 glioma cells: regulation by cyclic AMP.

    Science.gov (United States)

    Peakman, M C; Hill, S J

    1994-12-01

    1. The effects of histamine receptor agonists and antagonists on phospholipid hydrolysis in rat-derived C6 glioma cells have been investigated. 2. Histamine H1 receptor-stimulation caused a concentration-dependent increase in the accumulation of total [3H]-inositol phosphates in cells prelabelled with [3H]-myo-inositol. The rank order of agonist potencies was histamine (EC50 = 24 microM) > N alpha-methylhistamine (EC50 = 31 microM) > 2-thiazolylethylamine (EC50 = 91 microM). 3. The response to 0.1 mM histamine was antagonized in a concentration-dependent manner by the H1-antagonists, mepyramine (apparent Kd = 1 nM) and (+)-chlorpheniramine (apparent Kd = 4 nM). In addition, (-)-chlorpheniramine was more than two orders of magnitude less potent than its (+)-stereoisomer. 4. Elevation of intracellular cyclic AMP accumulation with forskolin (10 microM, EC50 = 0.3 microM), isoprenaline (1 microM, EC50 = 4 nM) or rolipram (0.5 mM), significantly reduced the histamine-mediated (0.1 mM) inositol phosphate response by 37%, 43% and 26% respectively. In contrast, 1,9-dideoxyforskolin did not increase cyclic AMP accumulation and had no effect on the phosphoinositide response to histamine. 5. These data indicate the presence of functionally coupled, endogenous histamine H1 receptors in C6 glioma cells. Furthermore, the results also indicate that H1 receptor-mediated phospholipid hydrolysis is inhibited by the elevation of cyclic AMP levels in these cells.

  5. Multiple Targeting Approaches on Histamine H3 Receptor Antagonists

    Directory of Open Access Journals (Sweden)

    Mohammad eKhanfar

    2016-05-01

    Full Text Available With the very recent market approval of pitolisant (Wakix®, the interest in clinical applications of novel multifunctional histamine H3 receptor antagonists has clearly increased. Since histamine H3 receptor antagonists in clinical development have been tested for a variety of different indications, the combination of pharmacological properties in one molecule for improved pharmacological effects and reduced unwanted side-effects is rationally based on the increasing knowledge on the complex neurotransmitter regulations. The polypharmacological approaches on histamine H3 receptor antagonists on different G-protein coupled receptors, transporters, enzymes as well as on NO-signaling mechanism are described, supported with some lead structures.

  6. The future antihistamines: histamine H3 and H4 receptor ligands.

    Science.gov (United States)

    Yu, Fuqu; Bonaventure, Pascal; Thurmond, Robin L

    2010-01-01

    The field of histamine research has progressed far from a century ago when the first biological functions of histamine were identified. It is now known that histamine function is mediated by four histamine receptors, which belong to the G-protein-coupled receptor family. While antihistamines that target the first two receptors have enjoyed clinical and commercial success, efforts to find new antihistamines against the histamine H3 and H4 receptors are still in the early stages. Here we will review the therapeutic potential of targeting these new histamine receptors.

  7. Endogenous expression of histamine H1 receptors functionally coupled to phosphoinositide hydrolysis in C6 glioma cells: regulation by cyclic AMP.

    OpenAIRE

    Peakman, M C; Hill, S. J.

    1994-01-01

    1. The effects of histamine receptor agonists and antagonists on phospholipid hydrolysis in rat-derived C6 glioma cells have been investigated. 2. Histamine H1 receptor-stimulation caused a concentration-dependent increase in the accumulation of total [3H]-inositol phosphates in cells prelabelled with [3H]-myo-inositol. The rank order of agonist potencies was histamine (EC50 = 24 microM) > N alpha-methylhistamine (EC50 = 31 microM) > 2-thiazolylethylamine (EC50 = 91 microM). 3. The response t...

  8. The Histamine H4 Receptor: From Orphan to the Clinic

    Directory of Open Access Journals (Sweden)

    Robin L. Thurmond

    2015-03-01

    Full Text Available The histamine H4 receptor (H4R was first noted as a sequence in genomic databases that had features of a G-protein coupled receptor. This putative receptor was found to bind histamine consistent with its homology to other histamine receptors and thus became the fourth member of the histamine receptor family. Due to the previous success of drugs that target the H1 and H2 receptors, an effort was made to understand the function of this receptor and determine if it represented a drug target. Taking advantage of the vast literature on histamine, a search for histamine activity that did not appear to be mediated by the other three histamine receptors was undertaken. From this asthma and pruritus emerged as areas of particular interest. Histamine has long been suspected to play a role in the pathogenesis of asthma, but antihistamines that target the H1 and H2 receptors have not been shown to be effective for this condition. The use of selective ligands in animal models of asthma has now potentially filled this gap by showing a role for the H4R in mediating lung function and inflammation. A similar story exists for chronic pruritus associated with conditions such as atopic dermatitis. Antihistamines that target the H1 receptor are effective in reducing acute pruritus, but are ineffective in pruritus experienced by patients with atopic dermatitis. As for asthma, animal models have now suggested a role for the H4R in mediating pruritic responses, with antagonists to the H4R reducing pruritus in a number of different conditions. The anti-pruritic effect of H4R antagonists has recently been shown in human clinical studies, validating the preclinical findings in the animal models. A selective H4R antagonist inhibited histamine-induced pruritus in health volunteers and reduced pruritus in patients with atopic dermatitis. The history to date of the H4R provides an excellent example of the deorphanization of a novel receptor and the translation of this into

  9. Effects of olopatadine hydrochloride, a histamine h(1) receptor antagonist, on histamine-induced skin responses.

    Science.gov (United States)

    Hashimoto, Takashi; Ishii, Norito; Hamada, Takahiro; Dainichi, Teruki; Karashima, Tadashi; Nakama, Takekuni; Yasumoto, Shinichiro

    2010-01-01

    Effects of olopatadine hydrochloride, a histamine H(1) receptor antagonist, on histamine-induced skin responses were evaluated in 10 healthy subjects in comparison with placebo, fexofenadine hydrochloride, and bepotastine besilate. Olopatadine significantly suppressed histamine-induced wheal, flare, and itch, starting 30 minutes after oral administration. Olopatadine was more effective than fexofenadine and bepotastine. None of the drugs studied impaired performance of word processing tasks. These results suggest that olopatadine can suppress skin symptoms caused by histamine soon after administration.

  10. Effects of Olopatadine Hydrochloride, a Histamine H1 Receptor Antagonist, on Histamine-Induced Skin Responses

    Science.gov (United States)

    Hashimoto, Takashi; Ishii, Norito; Hamada, Takahiro; Dainichi, Teruki; Karashima, Tadashi; Nakama, Takekuni; Yasumoto, Shinichiro

    2010-01-01

    Effects of olopatadine hydrochloride, a histamine H1 receptor antagonist, on histamine-induced skin responses were evaluated in 10 healthy subjects in comparison with placebo, fexofenadine hydrochloride, and bepotastine besilate. Olopatadine significantly suppressed histamine-induced wheal, flare, and itch, starting 30 minutes after oral administration. Olopatadine was more effective than fexofenadine and bepotastine. None of the drugs studied impaired performance of word processing tasks. These results suggest that olopatadine can suppress skin symptoms caused by histamine soon after administration. PMID:20886023

  11. En route to new blockbuster antihistamines:surveying the offspring of the expanding histamine receptor family

    NARCIS (Netherlands)

    Leurs, R.; Vischer, H.F.; Wijtmans, M.; De Esch, I.J.

    2011-01-01

    With the recognition of two new histamine receptors at the start of the new millennium, the field of histamine research has seen a clear revival. In the last 10 years, many academic and industrial groups have taken up the challenge to target these new members of the aminergic G-protein-coupled

  12. Molecular and biochemical pharmacology of the histamine H4 receptor.

    Science.gov (United States)

    Leurs, Rob; Chazot, Paul L; Shenton, Fiona C; Lim, Herman D; de Esch, Iwan J P

    2009-05-01

    The elucidation of the human genome has had a major impact on histamine receptor research. The identification of the human H4 receptor by several groups has been instrumental for a new appreciation of the role of histamine in the modulation of immune function. In this review, we summarize the historical developments and the molecular and biochemical pharmacology of the H4 receptor.

  13. Effects of Olopatadine Hydrochloride, a Histamine H 1 Receptor Antagonist, on Histamine-Induced Skin Responses

    OpenAIRE

    Takashi Hashimoto; Norito Ishii; Takahiro Hamada; Teruki Dainichi; Tadashi Karashima; Takekuni Nakama; Shinichiro Yasumoto

    2010-01-01

    Effects of olopatadine hydrochloride, a histamine H1 receptor antagonist, on histamine-induced skin responses were evaluated in 10 healthy subjects in comparison with placebo, fexofenadine hydrochloride, and bepotastine besilate. Olopatadine significantly suppressed histamine-induced wheal, flare, and itch, starting 30 minutes after oral administration. Olopatadine was more effective than fexofenadine and bepotastine. None of the drugs studied impaired performance of word processing tasks. Th...

  14. Histamine H4 receptor antagonists are superior to traditional antihistamines in the attenuation of experimental pruritus.

    Science.gov (United States)

    Dunford, Paul J; Williams, Kacy N; Desai, Pragnya J; Karlsson, Lars; McQueen, Daniel; Thurmond, Robin L

    2007-01-01

    Histamine is a potent mediator of itch in humans, yet histamine H(1) receptor antagonists have been shown to be of limited use in the treatment of certain chronic pruritic diseases. The histamine H(4) receptor is a recently described histamine receptor, expressed on hematopoietic cells, linked to the pathology of allergy and asthma. The contribution of the novel histamine H(4) receptor to histaminergic and allergic pruritus was investigated. Histamine and a selective histamine H(4) receptor agonist caused scratching responses in mice, which were almost completely attenuated in histamine H(4) receptor knockout mice or by pretreatment with the selective histamine H(4) receptor antagonist, JNJ 7777120. Pruritus induced by allergic mechanisms was also potently inhibited with histamine H(4) receptor antagonist treatment or in histamine H(4) receptor knockout mice. In all cases, the inhibitory effect of histamine H(4) receptor antagonist was greater than those observed with histamine H(1) receptor antagonists. The histamine H(4) receptor-mediated pruritus was shown to be independent of mast cells or other hematopoietic cells and may result from actions on peripheral neurons. These results demonstrate that the histamine H(4) receptor is involved in pruritic responses in mice to a greater extent than the histamine H(1) receptor. Histamine H(4) receptor antagonists may have therapeutic utility for treating chronic pruritic diseases in humans where histamine H(1) receptor antagonists are not effective.

  15. Role of Histamine and Its Receptors in Cerebral Ischemia

    Science.gov (United States)

    2012-01-01

    Histamine is recognized as a neurotransmitter or neuromodulator in the brain, and it plays a major role in the pathogenic progression after cerebral ischemia. Extracellular histamine increases gradually after ischemia, and this may come from histaminergic neurons or mast cells. Histamine alleviates neuronal damage and infarct volume, and it promotes recovery of neurological function after ischemia; the H1, H2, and H3 receptors are all involved. Further studies suggest that histamine alleviates excitotoxicity, suppresses the release of glutamate and dopamine, and inhibits inflammation and glial scar formation. Histamine may also affect cerebral blood flow by targeting to vascular smooth muscle cells, and promote neurogenesis. Moreover, endogenous histamine is an essential mediator in the cerebral ischemic tolerance. Due to its multiple actions, affecting neurons, glia, vascular cells, and inflammatory cells, histamine is likely to be an important target in cerebral ischemia. But due to its low penetration of the blood-brain barrier and its wide actions in the periphery, histamine-related agents, like H3 antagonists and carnosine, show potential for cerebral ischemia therapy. However, important questions about the molecular aspects and pathophysiology of histamine and related agents in cerebral ischemia remain to be answered to form a solid scientific basis for therapeutic application. PMID:22860191

  16. International Union of Basic and Clinical Pharmacology. XCVIII. Histamine Receptors

    Science.gov (United States)

    Chazot, Paul L.; Cowart, Marlon; Gutzmer, Ralf; Leurs, Rob; Liu, Wai L. S.; Stark, Holger; Thurmond, Robin L.; Haas, Helmut L.

    2015-01-01

    Histamine is a developmentally highly conserved autacoid found in most vertebrate tissues. Its physiological functions are mediated by four 7-transmembrane G protein–coupled receptors (H1R, H2R, H3R, H4R) that are all targets of pharmacological intervention. The receptors display molecular heterogeneity and constitutive activity. H1R antagonists are long known antiallergic and sedating drugs, whereas the H2R was identified in the 1970s and led to the development of H2R-antagonists that revolutionized stomach ulcer treatment. The crystal structure of ligand-bound H1R has rendered it possible to design new ligands with novel properties. The H3R is an autoreceptor and heteroreceptor providing negative feedback on histaminergic and inhibition on other neurons. A block of these actions promotes waking. The H4R occurs on immuncompetent cells and the development of anti-inflammatory drugs is anticipated. PMID:26084539

  17. Histamine type 1-receptor activation by low dose of histamine undermines human glomerular slit diaphragm integrity.

    Science.gov (United States)

    Veglia, Eleonora; Pini, Alessandro; Moggio, Aldo; Grange, Cristina; Premoselli, Federica; Miglio, Gianluca; Tiligada, Katerina; Fantozzi, Roberto; Chazot, Paul L; Rosa, Arianna Carolina

    2016-12-01

    Histamine has been reported to decrease the ultrafiltration coefficient, which inversely correlates with glomerular permselectivity, however the mechanism(s) underling this effect have never been investigated. This study aimed to assess whether histamine could exert a direct detrimental effect on podocyte permeability and the possible involvement of two key proteins for the glomerular slit diaphragm (SD) integrity, zonula occludens-1 (ZO-1) and P-cadherin. The effect of histamine (100 pM-1000nM) on coloured podocytes junctional integrity was evaluated functionally by a transwell assay of monolayer permeability and morphologically by electron microscopy. Histamine receptor (H1-4R) presence was evaluated at both mRNA (RT-PCR) and protein (immunofluorescence) levels. The Kd and Bmax values for [3H]mepyramine were determined by saturation binding analysis; IP1 and cAMP production evoked by histamine were measured by TR-FRET. ZO-1, P-cadherin and vimentin expression was assessed by qRT-PCR and quantitative immunoblotting. Histamine elicited a time- and sigmoidal dose-dependent (maximum effect at 8h, 10nM) increase in podocyte paracellular permeability widening the paracellular spaces. Only H1R was predominantly localised to the podocyte membrane. Consistently, histamine elicited a sigmoidal dose-dependent increase in IP1, but not in cAMP. Histamine exposure evoked a concentration-dependent reduction in both ZO-1 and P-cadherin and a parallel induction of vimentin mRNA expression with a maximum effect after 6h, and protein expression with a maximum effect after 8h. These effects were prevented by the selective H1R antagonist chlorpheniramine. In conclusion, our data demonstrate that histamine, via the H1R, modifies SD morphological and functional integrity, in part, by decreasing the expression of ZO-1 and P-cadherin. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Ligands of histamine receptors modulate acid-sensing ion channels.

    Science.gov (United States)

    Shteinikov, V Y; Korosteleva, A S; Tikhonova, T B; Potapieva, N N; Tikhonov, D B

    2017-09-02

    Recently we found that synthetic compounds containing amino group linked to hydrophobic or aromatic moiety are potent modulators of the proton-gated channels (ASICs). These structures have clear similarity with ligands of histamine receptors. We have also demonstrated that histamine potentiates homomeric ASIC1a by shifting its activation dependence to less acidic conditions. In the present work the action of a series of histamine receptors ligands on recombinant ASIC1a and ASIC2a was characterized. Two types of action were found for ASIC1a. 1-methylhistamine, N-alpha-methylhistamine, dimaprit and thioperamide caused significant potentiation, which was pH-dependent and voltage-independent. The H4R antagonist A943931 caused inhibition, which is likely due to voltage-dependent pore block. ASIC2a were virtually insensitive to the drugs tested. We conclude that ligands of histamine receptors should also be considered as ASIC modulators. Copyright © 2017. Published by Elsevier Inc.

  19. Histamine H4 receptor antagonists: the new antihistamines?

    Science.gov (United States)

    Fung-Leung, Wai-Ping; Thurmond, Robin L; Ling, Ping; Karlsson, Lars

    2004-11-01

    Antihistamines (histamine H1 receptor antagonists) are a mainstay treatment for atopic allergy, yet they are only partially effective in relieving the symptoms of the disease. They also have very limited value for the treatment of asthma, despite the well-characterized bronchoconstrictory effects of histamine. The recent discovery of a fourth histamine receptor (H4), and the realization that it is exclusively expressed on hematopoietic cell types that are most implicated in the development and symptomatology of allergy and asthma, suggests that pharmacological targeting of the H4 receptor, either alone or in combination with H1 receptor antagonists, may prove useful for treating both allergy and asthma. Here we review the known biology associated with the H4 receptor, as well the effects of a highly selective H1 receptor antagonist.

  20. Histamine and histamine type-2 receptor antagonists in psoriasis. Mechanisms and speculations

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen

    1991-01-01

    The findings that the immunosuppressant cyclosporine A (CsA) improves psoriasis raise the possibility that cellular immune processes may play a major role in the pathogenesis of this disease. It is broadly agreed that histamine released by mast cells is one of the molecules involved in the pathog......The findings that the immunosuppressant cyclosporine A (CsA) improves psoriasis raise the possibility that cellular immune processes may play a major role in the pathogenesis of this disease. It is broadly agreed that histamine released by mast cells is one of the molecules involved...... in the pathogenesis. This is supported by the findings that CsA and methotrexate (Mxt) reduce formation and release of histamine. However, the well known side-effects of CsA and Mxt may argue potential use of other agents acting on formation and action of histamine. Such agents may be the histamine-2 receptor...... antagonists, previously reported to have a clinical effect on psoriasis. But randomised short-term studies have disclosed that these drugs have no beneficial or even an aggravating effect on the disease. This article reports on recent findings of improvement in psoriasis using high doses of the histamine-2...

  1. Histamine H2 receptor - Involvement in gastric ulceration

    Science.gov (United States)

    Brown, P. A.; Vernikos-Danellis, J.; Brown, T. H.

    1976-01-01

    The involvement of the H1 and H2 receptors for histamine in the pathogenesis of gastric ulcers was investigated in rats. Metiamide, an H2 receptor antagonist, reliably reduced ulceration produced by stress alone or by a combination of stress and aspirin. In contrast, pyrilamine, which blocks only the H1 receptor, was without effect under these same conditions. The results support the hypothesis that histamine mediates both stress and stress plus aspirin induced ulceration by a mechanism involving the H2 receptor.

  2. In vitro study of histamine and histamine receptor ligands influence on the adhesion of purified human eosinophils to endothelium.

    Science.gov (United States)

    Grosicki, Marek; Wójcik, Tomasz; Chlopicki, Stefan; Kieć-Kononowicz, Katarzyna

    2016-04-15

    It is a well-known fact that histamine is involved in eosinophil-dependent inflammatory responses including cellular chemotaxis and migration. Nevertheless, the relative role of histamine receptors in the mechanisms of eosinophils adhesion to endothelial cells is not known. Therefore the aim of presented study was to examine the effect of selective histamine receptors ligands on eosinophils adhesion to endothelium. For that purpose the highly purified human eosinophils have been isolated from the peripheral blood. The viability and functional integrity of isolated eosinophils have been validated in several tests. Histamine as well as 4-methylhistamine (selective H4 agonist) in concentration-dependent manner significantly increased number of eosinophils that adhere to endothelium. Among the selective histamine receptors antagonist or H1 inverse agonist only JNJ7777120 (histamine H4 antagonist) and thioperamide (dual histamine H3/H4 antagonist) had direct effect on eosinophils adhesion to endothelial cells. Antagonists of H1 (diphenhydramine, mepyramine) H2 (ranitidine and famotidine) and H3 (pitolisant) histamine receptors were ineffective. To the best of our knowledge, this is the first study to demonstrate that histamine receptor H4 plays a dominant role in histamine-induced eosinophils adhesion to endothelium. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Identification of the antiarrhythmic drugs amiodarone and lorcainide as potent H3 histamine receptor inverse agonists.

    Science.gov (United States)

    Del Tredici, Andria L; Ma, Jian-Nong; Piu, Fabrice; Burstein, Ethan S

    2014-01-01

    Use of molecular pharmacology to reprofile older drugs discovered before the advent of recombinant technologies is a fruitful method to elucidate mechanisms of drug action, expand understanding of structure-activity relationships between drugs and receptors, and in some cases, repurpose approved drugs. The H3 histamine receptor is a G-protein-coupled receptor (GPCR) primarily expressed in the central nervous system where among many things it modulates cognitive processes, nociception, feeding and drinking behavior, and sleep/wakefulness. In binding assays and functional screens of the H3 histamine receptor, the antiarrhythmic drugs lorcainide and amiodarone were identified as potent, selective antagonists/inverse agonists of human and rat H3 histamine receptors, with relatively little or no activity at over 20 other monoamine GPCRs, including H1, H2, and H4 receptors. Potent antagonism of H3 receptors was unique to amiodarone and lorcainide of 20 antiarrhythmic drugs tested, representing six pharmacological classes. These results expand the pharmacophore of H3 histamine receptor antagonist/inverse agonists and may explain, in part, the effects of lorcainide on sleep in humans.

  4. The histamine H3 receptor as a novel therapeutic target for cognitive and sleep disorders.

    Science.gov (United States)

    Passani, Maria Beatrice; Lin, Jian-Sheng; Hancock, Arthur; Crochet, Sylvain; Blandina, Patrizio

    2004-12-01

    Histamine H3 receptor pharmacology, functions and biochemistry are far from being fully understood; however, progress is being made. Activation of this Gi/GO-protein-coupled receptor affects cognition, the sleep-wake cycle, obesity and epilepsy, which are physiological and pathological conditions that are the main focus of research into the therapeutic potential of selective H3 receptor ligands. This heterogeneity of targets can be reconciled partially by the fact that the histamine system constitutes one of the most important brain-activating systems and that H3 receptors regulate the activity of histamine and other neurotransmitter systems. Furthermore, the H3 receptor shows functional constitutive activity, polymorphisms in humans and rodents with a differential distribution of splice variants in the CNS, and potential coupling to different intracellular signal transduction mechanisms. In light of the genetic, pharmacological and functional complexity of the H3 receptor, the importance of the histamine system as a therapeutic target to control the sleep-wake cycle and cognitive disorders will be discussed.

  5. Histamine and histamine receptors in Tourette syndrome and other neuropsychiatric conditions.

    Science.gov (United States)

    Rapanelli, Maximiliano; Pittenger, Christopher

    2016-07-01

    The potential contributions of dysregulation of the brain's histaminergic modulatory system to neuropsychiatric disease, and the potential of histamine-targeting medications as therapeutic agents, are gradually coming into focus. The H3R receptor, which is expressed primarily in the central nervous system, is a promising pharmacotherapeutic target. Recent evidence for a contribution of histamine dysregulation to Tourette syndrome and tic disorders is particularly strong; although specific mutations in histamine-associated genes are rare, they have led to informative studies in animal models that may pave the way for therapeutic advances. A controlled study of an H3R antagonist in Tourette syndrome is ongoing. Preclinical studies of H3R antagonists in schizophrenia, attention deficit disorder, and narcolepsy have all shown promise. Recently reported controlled studies have been disappointing in schizophrenia and attention deficit disorder, but the H3R antagonist pitolisant shows promise in the treatment of narcolepsy and excessive daytime sleepiness and is currently under regulatory review for these conditions. This article is part of the Special Issue entitled 'Histamine Receptors'. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. A bioinformatics search for selective histamine h4 receptor antagonists through structure-based virtual screening strategies.

    Science.gov (United States)

    Christopher, Fenila; Thangam, Elden Berla; Suresh, Muthaiyan Xavier

    2012-05-01

    The prevalence of allergic disease is increasing dramatically in the developed world. Studies of allergic diseases have clearly demonstrated that histamine plays an important role in the pathogenesis of the early-phase allergic response. Histamine effects are mediated by H1, H2, H3, and H4 receptors. The presence of the histamine H4 receptors on leukocytes and mast cells suggests that the new histamine receptor H4 plays an important role in the modulation of the immune system. Thus, histamine H4 receptor is an attractive target for anti-allergic therapy. In our present study, we have generated a histamine H4 receptor model using I-TASSER based on human B2-adrenergic G-protein-coupled receptor. Structurally similar compounds of the three known antagonists JNJ777120, thioperamide, and Vuf6002 were retrieved from PubChem, and database was prepared. Virtual screening of those databases was performed, and six compounds with high docking score were identified. Also the binding mode revealed that all the six compounds had interaction with Asp94 of the receptor. Our results serve as a starting point in the development of novel lead compounds in anti-allergic therapy. © 2012 John Wiley & Sons A/S.

  7. Expression of histamine receptors in the human endolymphatic sac

    DEFF Research Database (Denmark)

    Møller, M Nue; Kirkeby, S; Vikeså, J.

    2016-01-01

    in 2012. This leaves betahistine (Betaserc) as the only drug for potential prevention of the incapacitating attacks of dizziness, tinnitus and hearing loss. However, the histamine receptors targeted by betahistine have never been demonstrated in the human ES. Accordingly, this study aims to investigate...

  8. Rapid desensitization of the histamine H2 receptor on the human monocytic cell line U937

    NARCIS (Netherlands)

    Smit, M J; Leurs, R; Shukrula, S R; Bast, A; Timmerman, H

    1994-01-01

    In the present study we have subjected the histamine H2 receptor on the monocytic cell line U937 to a thorough pharmacological characterization using a series of selective histamine H1, H2 and H3 receptor agonists and antagonists. Recent reports have demonstrated the existence of a histamine H2

  9. Role of Histamine and Its Receptor Subtypes in Stimulation of Conjunctival Goblet Cell Secretion

    Science.gov (United States)

    Hayashi, Densen; Li, Dayu; Hayashi, Chisato; Shatos, Marie; Hodges, Robin R.; Dartt, Darlene A.

    2012-01-01

    Purpose. The purpose of this study was to determine the effect of histamine and its receptors on goblet cell secretion. Methods. Cultured rat and human goblet cells were grown in RPMI 1640. Goblet cell secretion of high molecular weight glycoconjugate was measured by an enzyme-linked lectin assay. Cultured rat goblet cells were homogenized and either RNA was isolated for RT-PCR or proteins were isolated for Western blot analysis for presence of histamine receptors subtypes H1 through H4. The localization of these receptors was determined in rat and human goblet cells by immunofluorescence microscopy. Results. Histamine stimulated goblet cell secretion in a concentration- and time-dependent manner. All four histamine receptors were present in cultured rat and human goblet cells. Use of agonists specific to individual histamine receptor subtypes indicated that the rank order of agonist stimulation was H1 = H3 > H4 > H2. Using antagonists specific to individual histamine receptor subtypes determined that H2 and H3, but not the H1 and H4, antagonists, inhibited histamine-stimulated conjunctival goblet cell secretion. Conclusions. Rat and human conjunctival goblet cells are a direct target of histamine, which induces secretion. All four histamine receptors are present in rat and human conjunctiva and are active in rat conjunctival goblet cells. These findings suggest that all four histamine receptor subtypes are important for conjunctival goblet cell secretion. Blockage of histamine receptor subtypes could prevent the excess mucus production associated with ocular allergy. PMID:22467574

  10. Histamine receptors and antihistamines: from discovery to clinical applications.

    Science.gov (United States)

    Cataldi, Mauro; Borriello, Francesco; Granata, Francescopaolo; Annunziato, Lucio; Marone, Gianni

    2014-01-01

    The synthesis and the identification of histamine marked a milestone in both pharmacological and immunological research. Since Sir Henry Dale and Patrick Laidlaw described some of its physiological effects in vivo in 1910, histamine has been shown to play a key role in the control of gastric acid secretion and in allergic disorders. Using selective agonists and antagonists, as well as molecular biology tools, four histamine receptors (H1R, H2R, H3R and H4R) have been identified. The Nobel Prize in Physiology and Medicine was awarded to Daniel Bovet in 1957 for the discovery of antihistamines (anti-H1R) and to Sir James Black in 1988 for the identification of anti-H2R antagonists. Anti-H1R and anti-H2R histamine receptor antagonists have revolutionized the treatment of certain allergic disorders and gastric acid-related conditions, respectively. More recently, anti-H3R antagonists have entered early-phase clinical trials for possible application in obesity and a variety of neurologic disorders. The preferential expression of H4R by several immune cells and its involvement in the development of allergic inflammation provide the rationale for the use of anti-H4R antagonists in allergic and in other immune-related disorders. © 2014 S. Karger AG, Basel.

  11. Histamine induces NF-κB controlled cytokine secretion by orbital fibroblasts via histamine receptor type-1.

    Science.gov (United States)

    Virakul, Sita; Phetsuksiri, Tanachaporn; van Holten-Neelen, Conny; Schrijver, Benjamin; van Steensel, Leendert; Dalm, Virgil A S H; Paridaens, Dion; van den Bosch, Willem A; van Hagen, P Martin; Dik, Willem A

    2016-06-01

    Mast cells and their products are likely to be involved in regulating orbital fibroblast activity in Graves' Ophthalmopathy (GO). Histamine is abundantly present in granules of mast cells and is released upon mast cell activation. However, the effect of histamine on orbital fibroblasts has not been examined so far. Orbital tissues from GO patients and controls were analyzed for the presence of mast cells using toluidine blue staining and immunohistochemical detection of CD117 (stem cell factor receptor). Orbital fibroblasts were cultured from GO patients and healthy controls, stimulated with histamine and cytokines (IL-6, IL-8, CCL2, CCL5, CCL7, CXCL10 and CXCL11) were measured in culture supernatants. Also hyaluronan levels were measured in culture supernatants and hyaluronan synthase (HAS) and hyaluronidase (HYAL) gene expression levels were determined. In addition, histamine receptor subtype gene expression levels were examined as well as the effect of the histamine receptor-1 (HRH1) antagonist loratadine and NF-κB inhibitor SC-514 on histamine-induced cytokine production. Mast cell numbers were increased in GO orbital tissues. Histamine stimulated the production of IL-6, IL-8 and CCL2 by orbital fibroblasts, while it had no effect on the production of CCL5, CCL7, CXCL10, CXCL11 and hyaluronan. Orbital fibroblasts expressed HRH1 and loratadine and SC-514 both blocked histamine-induced IL-6, IL-8 and CCL2 production by orbital fibroblasts. In conclusion, this study demonstrates that histamine can induce the production of NF-κB controlled-cytokines by orbital fibroblasts, which supports a role for mast cells in GO. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Vasopeptidase-activated latent ligands of the histamine receptor-1.

    Science.gov (United States)

    Gera, Lajos; Roy, Caroline; Charest-Morin, Xavier; Marceau, François

    2013-11-01

    Whether peptidases present in vascular cells can activate prodrugs active on vascular cells has been tested with 2 potential latent ligands of the histamine H1 receptor (H1R). First, a peptide consisting of the antihistamine cetirizine (CTZ) condensed at the N-terminus of ε-aminocaproyl-bradykinin (εACA-BK) was evaluated for an antihistamine activity that could be revealed by degradation of the peptide part of the molecule. CTZ-εACA-BK had a submicromolar affinity for the BK B2 receptor (B2R; IC50 of 590 nM, [(3)H]BK binding competition), but a non-negligible affinity for the human H1 receptor (H1R; IC50 of 11 μM for [(3)H]pyrilamine binding). In the human isolated umbilical vein, a system where both endogenous B2R and H1R mediate strong contractions, CTZ-εACA-BK exerted mild antagonist effects on histamine-induced contraction that were not modified by omapatrilat or by a B2R antagonist that prevents endocytosis of the BK conjugate. Cells expressing recombinant ACE or B2R incubated with CTZ-εACA-BK did not release a competitor of [(3)H]pyrilamine binding to H1Rs. Thus, there is no evidence that CTZ-εACA-BK can release free cetirizine in biological environments. The second prodrug was a blocked agonist, L-alanyl-histamine, potentially activated by aminopeptidase N (APN). This compound did not compete for [(3)H]pyrilamine binding to H1Rs. The human umbilical vein contractility assay responded to L-alanyl-histamine (EC50 54.7 μM), but the APN inhibitor amastatin massively (17-fold) reduced its apparent potency. Amastatin did not influence the potency of histamine as a contractile agent. One of the 2 tested latent H1R ligands, L-alanyl-histamine, supported the feasibility of pro-drug activation by vascular ectopeptidases. © 2013.

  13. Docking-based Screening of Ficus religiosa Phytochemicals as Inhibitors of Human Histamine H2 Receptor.

    Science.gov (United States)

    Chaudhary, Amit; Yadav, Birendra Singh; Singh, Swati; Maurya, Pramod Kumar; Mishra, Alok; Srivastva, Shweta; Varadwaj, Pritish Kumar; Singh, Nand Kumar; Mani, Ashutosh

    2017-10-01

    Ficus religiosa L. is generally known as Peepal and belongs to family Moraceae. The tree is a source of many compounds having high medicinal value. In gastrointestinal tract, histamine H2 receptors have key role in histamine-stimulated gastric acid secretion. Their over stimulation causes its excessive production which is responsible for gastric ulcer. This study aims to screen the range of phytochemicals present in F. religiosa for binding with human histamine H2 and identify therapeutics for a gastric ulcer from the plant. In this work, a 3D-structure of human histamine H2 receptor was modeled by using homology modeling and the predicted model was validated using PROCHECK. Docking studies were also performed to assess binding affinities between modeled receptor and 34 compounds. Molecular dynamics simulations were done to identify most stable receptor-ligand complexes. Absorption, distribution, metabolism, excretion, and screening was done to evaluate pharmacokinetic properties of compounds. The results suggest that seven ligands, namely, germacrene, bergaptol, lanosterol, Ergost-5-en-3beta-ol, α-amyrin acetate, bergapten, and γ-cadinene showed better binding affinities. Among seven phytochemicals, lanosterol and α-amyrin acetate were found to have greater stability during simulation studies. These two compounds may be a suitable therapeutic agent against histamine H2 receptor. This study was performed to screen antiulcer compounds from F. religiosa. Molecular modeling, molecular docking and MD simulation studies were performed with selected phytochemicals from F. religiosa. The analysis suggests that Lanosterol and α-amyrin may be a suitable therapeutic agent against histamine H2 receptor. This study facilitates initiation of the herbal drug discovery process for the antiulcer activity. Abbreviations used: ADMET: Absorption, distribution, metabolism, excretion and toxicity, DOPE: Discrete Optimized Potential Energy, OPLS: Optimized potential for liquid

  14. Probing an artificial polypeptide receptor library using a series of novel histamine H3 receptor ligands.

    Science.gov (United States)

    Bak, Andrzej; Daszykowski, Michal; Kaminski, Zbigniew; Kiec-Kononowicz, Katarzyna; Kuder, Kamil; Fraczyk, Justyna; Kolesinska, Beata; Ciosek, Patrycja; Polanski, Jaroslaw

    2014-02-01

    An artificial polypeptide receptor (APR) library was created by using the self-organization of N-lipidated peptides attached to cellulose via m-aminophenylamino-1,3,5-triazine. The response of the library was probed using a series of novel H3 receptor ligands. Since no guidelines on how to design an APRs selective vs certain receptor types exist, a diverse set of amino acids (Ala, Trp, Pro, Glu, His, Lys and Ser) were used and coupled with one of three gating fatty acids (palmitic, ricinoleic or capric). A competitive adsorption-desorption of an appropriate reporter dye was used for the indirect visualization of the interactions of guests with particular receptors. The resulted library response to individual inhibitors was then arranged in a matrix, preprocessed and analyzed using the principal component analysis (PCA) and partial least squares (PLS) method. The most important conclusion obtained from the PCA analysis is that the library differentiates the probed compounds according to the lipophilicity of the gating unit. The PC3 with a dominant absolute contribution of the receptors containing Glu allowed for the best separation of the ligands with respect to their activity. This conclusion is in agreement with the fact that Glu 206 is a genuine ligand counterpart in the natural histamine receptor.

  15. Cysteinyl leukotrienes mediate histamine hypersensitivity ex vivo by increasing histamine receptor numbers

    NARCIS (Netherlands)

    Pynaert, G.; Grooten, J.; van Deventer, S. J.; Peppelenbosch, M. P.

    1999-01-01

    Hyperresponsiveness to histamine is a key feature of a variety of pathological conditions, including bronchial asthma, food allergy, colitis ulcerosa, and topical allergic disorders. Cells isolated from hyperresponsive individuals do not display exaggerated histamine responses ex vivo and thus the

  16. Histamine Stimulates Hydrogen Peroxide Production by Bronchial Epithelial Cells via Histamine H1 Receptor and Dual Oxidase

    Science.gov (United States)

    Rada, Balázs; Boudreau, Howard E.; Park, Jonathan J.

    2014-01-01

    Oxidative stress has been implicated in the pathogenesis of bronchial asthma. Besides granulocytes, the airway epithelium can produce large amounts of reactive oxygen species and can contribute to asthma-related oxidative stress. Histamine is a major inflammatory mediator present in large quantities in asthmatic airways. Whether histamine triggers epithelium-derived oxidative stress is unknown. We therefore aimed at characterizing human airway epithelial H2O2 production stimulated by histamine. We found that air–liquid interface cultures of primary human bronchial epithelial cells (BECs) and an immortalized BEC model (Cdk4/hTERT HBEC) produce H2O2 in response to histamine. The main source of airway epithelial H2O2 is an NADPH dual oxidase, Duox1. Out of the four histamine receptors (H1R–H4R), H1R has the highest expression in BECs and mediates the H2O2–producing effects of histamine. IL-4 induces Duox1 gene and protein expression levels and enhances histamine-induced H2O2 production by epithelial cells. Using HEK-293 cells expressing Duox1 or Duox2 and endogenous H1R, histamine triggers an immediate intracellular calcium signal and H2O2 release. Overexpression of H1R further increases the oxidative output of Duox-expressing HEK-293 cells. Our observations show that BECs respond to histamine with Duox-mediated H2O2 production. These findings reveal a mechanism that could be an important contributor to oxidative stress characteristic of asthmatic airways, suggesting novel therapeutic targets for treating asthmatic airway disease. PMID:23962049

  17. Clinical Development of Histamine H4 Receptor Antagonists.

    Science.gov (United States)

    Thurmond, Robin L; Venable, Jennifer; Savall, Brad; La, David; Snook, Sandra; Dunford, Paul J; Edwards, James P

    2017-01-01

    The discovery of the histamine H4 receptor (H4R) provided a new avenue for the exploration of the physiological role of histamine, as well as providing a new drug target for the development of novel antihistamines. The first step in this process was the identification of selective antagonists to help unravel the pharmacology of the H4R relative to other histamine receptors. The discovery of the selective H4R antagonist JNJ 7777120 was vital for showing a role for the H4R in inflammation and pruritus. While this compound has been very successful as a tool for understanding the function of the receptor, it has drawbacks, including a short in vivo half-life and hypoadrenocorticism toxicity in rats and dogs, that prevented advancing it into clinical studies. Further research let to the discovery of JNJ 39758979, which, similar to JNJ 7777120, was a potent and selective H4R antagonist and showed anti-inflammatory and anti-pruritic activity preclinically. JNJ 39758979 advanced into human clinical studies and showed efficacy in reducing experimental pruritus and in patients with atopic dermatitis. However, development of this compound was terminated due to the occurrence of drug-induced agranulocytosis. This was overcome by developing another H4R antagonist with a different chemical structure, toreforant, that does not appear to have this side effect. Toreforant has been tested in clinical studies in patients with rheumatoid arthritis, asthma, or psoriasis. In conclusions there have been many H4R antagonists reported in the literature, but only a few have been studied in humans underscoring the difficulty in finding ligands with all of the properties necessary for testing in the clinic. Nevertheless, the clinical data to date suggests that H4R antagonists can be beneficial in treating atopic dermatitis and pruritus.

  18. Increased brain histamine H3 receptor expression during hibernation in golden-mantled ground squirrels

    Directory of Open Access Journals (Sweden)

    Anichtchik Oleg V

    2003-09-01

    Full Text Available Abstract Background Hibernation is a state of extremely reduced physiological functions and a deep depression of CNS activity. We have previously shown that the histamine levels increase in the brain during hibernation, as does the ratio between histamine and its first metabolite, suggesting increased histamine turnover during this state. The inhibitory histamine H3 receptor has both auto- and heteroreceptor function, rendering it the most likely histamine receptor to be involved in regulating the activity of histamine as well as other neurotransmitters during hibernation. In view of accumulating evidence that there is a global depression of transcription and translation during hibernation, of all but a few proteins that are important for this physiological condition, we reasoned that an increase in histamine H3 receptor expression would clearly indicate an important hibernation-related function for the receptor. Results In this study we show, using in situ hybridization, that histamine H3 receptor mRNA increases in the cortex, caudate nucleus and putamen during hibernation, an increase that is accompanied by elevated receptor binding in the cerebral cortex, globus pallidus and substantia nigra. These results indicate that there is a hibernation-related increase in H3 receptor expression in cortical neurons and in striatopallidal and striatonigral GABAergic neurons. GTP-γ-S binding autoradiography shows that the H3 receptors in the globus pallidus and substantia nigra can be stimulated by histamine throughout the hibernation cycle, suggesting that they are functionally active during hibernation. Conclusions These results show that the histamine H3 receptor gene is one of the few with a transcript that increases during hibernation, indicating an important role for the receptor in regulating this state. Moreover, the receptor is functionally active in the basal ganglia, suggesting a function for it in regulating e.g. dopaminergic transmission

  19. Histamine acting on H1 receptor promotes inhibition of proliferation via PLC, RAC, and JNK-dependent pathways

    Energy Technology Data Exchange (ETDEWEB)

    Notcovich, Cintia [Laboratorio de Patologia y Farmacologia Molecular, Instituto de Biologia y Medicina Experimental (Argentina); Laboratorio de Farmacologia de Receptores, Catedra de Quimica Medicinal, Departamento de Farmacologia, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (Argentina); Diez, Federico [Laboratorio de Farmacologia de Receptores, Catedra de Quimica Medicinal, Departamento de Farmacologia, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (Argentina); Tubio, Maria Rosario [Laboratorio de Patologia y Farmacologia Molecular, Instituto de Biologia y Medicina Experimental (Argentina); Laboratorio de Farmacologia de Receptores, Catedra de Quimica Medicinal, Departamento de Farmacologia, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (Argentina); Baldi, Alberto [Laboratorio de Patologia y Farmacologia Molecular, Instituto de Biologia y Medicina Experimental (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Kazanietz, Marcelo G. [Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104 (United States); Davio, Carlos [Laboratorio de Farmacologia de Receptores, Catedra de Quimica Medicinal, Departamento de Farmacologia, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Shayo, Carina, E-mail: cshayo@dna.uba.ar [Laboratorio de Patologia y Farmacologia Molecular, Instituto de Biologia y Medicina Experimental (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina)

    2010-02-01

    It is well established that histamine modulates cell proliferation through the activation of the histamine H1 receptor (H1R), a G protein-coupled receptor (GPCR) that is known to couple to phospholipase C (PLC) activation via Gq. In the present study, we aimed to determine whether H1R activation modulates Rho GTPases, well-known effectors of Gq/G{sub 11}-coupled receptors, and whether such modulation influences cell proliferation. Experiments were carried out in CHO cells stably expressing H1R (CHO-H1R). By using pull-down assays, we found that both histamine and a selective H1R agonist activated Rac and RhoA in a time- and dose-dependent manner without significant changes in the activation of Cdc42. Histamine response was abolished by the H1R antagonist mepyramine, RGS2 and the PLC inhibitor U73122, suggesting that Rac and RhoA activation is mediated by H1R via Gq coupling to PLC stimulation. Histamine caused a marked activation of serum response factor activity via the H1R, as determined with a serum-responsive element (SRE) luciferase reporter, and this response was inhibited by RhoA inactivation with C3 toxin. Histamine also caused a significant activation of JNK which was inhibited by expression of the Rac-GAP {beta}2-chimaerin. On the other hand, H1R-induced ERK1/2 activation was inhibited by U73122 but not affected by C3 or {beta}2-chimaerin, suggesting that ERK1/2 activation was dependent on PLC and independent of RhoA or Rac. [{sup 3}H]-Thymidine incorporation assays showed that both histamine and the H1R agonist inhibited cell proliferation in a dose-dependent manner and that the effect was independent of RhoA but partially dependent on JNK and Rac. Our results reveal that functional coupling of the H1R to Gq-PLC leads to the activation of RhoA and Rac small GTPases and suggest distinct roles for Rho GTPases in the control of cell proliferation by histamine.

  20. Histamine H1 Receptor Gene Expression and Drug Action of Antihistamines.

    Science.gov (United States)

    Fukui, Hiroyuki; Mizuguchi, Hiroyuki; Nemoto, Hisao; Kitamura, Yoshiaki; Kashiwada, Yoshiki; Takeda, Noriaki

    2017-01-01

    The upregulation mechanism of histamine H1 receptor through the activation of protein kinase C-δ (PKCδ) and the receptor gene expression was discovered. Levels of histamine H1 receptor mRNA and IL-4 mRNA in nasal mucosa were elevated by the provocation of nasal hypersensitivity model rats. Pretreatment with antihistamines suppressed the elevation of mRNA levels. Scores of nasal symptoms were correlatively alleviated to the suppression level of mRNAs above. A correlation between scores of nasal symptoms and levels of histamine H1 receptor mRNA in the nasal mucosa was observed in patients with pollinosis. Both scores of nasal symptoms and the level of histamine H1 receptor mRNA were improved by prophylactic treatment of antihistamines. Similar to the antihistamines, pretreatment with antiallergic natural medicines showed alleviation of nasal symptoms with correlative suppression of gene expression in nasal hypersensitivity model rats through the suppression of PKCδ. Similar effects of antihistamines and antiallergic natural medicines support that histamine H1 receptor-mediated activation of histamine H1 receptor gene expression is an important signaling pathway for the symptoms of allergic diseases. Antihistamines with inverse agonist activity showed the suppression of constitutive histamine H1 receptor gene expression, suggesting the advantage of therapeutic effect.

  1. Pharmacoresistant temporal lobe epilepsy modifies histamine turnover and H3 receptor function in the human hippocampus and temporal neocortex.

    Science.gov (United States)

    Bañuelos-Cabrera, Ivette; Cuéllar-Herrera, Manola; Velasco, Ana Luisa; Velasco, Francisco; Alonso-Vanegas, Mario; Carmona, Francia; Guevara, Rosalinda; Arias-Montaño, José-Antonio; Rocha, Luisa

    2016-04-01

    Experiments were designed to evaluate the tissue content of tele-methylhistamine (t-MeHA) and histamine as well as H3 receptor (H3 Rs) binding and activation of the heterotrimeric guanine nucleotide binding αi/o proteins (Gαi/o) coupled to these receptors in the hippocampus and temporal neocortex of patients (n = 10) with pharmacoresistant mesial temporal lobe epilepsy (MTLE). Patients with MTLE showed elevated tissue content of t-MeHA in the hippocampus. Analyses revealed that a younger age at seizure onset was correlated with a higher tissue content of t-MeHA, lower H3 R binding, and lower efficacy of Gαi/o protein activation in the hippocampus. We conclude that the hippocampus shows a reduction in the H3 R function associated with enhanced histamine. In contrast, the temporal neocortex displayed a high efficacy of H3 Rs Gαi/o protein activation that was associated with low tissue contents of histamine and t-MeHA. These results indicate an overactivation of H3 Rs leading to decreased histamine in the temporal neocortex. However, this situation was lessened in circumstances such as a longer duration of epilepsy or higher seizure frequency. It is concluded that decrease in H3 Rs function and enhanced levels of histamine may contribute to the epileptic activity in the hippocampus and temporal neocortex of patients with pharmacoresistant MTLE. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

  2. Structural Analysis of the Histamine H1 Receptor.

    Science.gov (United States)

    Shiroishi, Mitsunori; Kobayashi, Takuya

    2017-01-01

    The crystal structure of the human histamine H1 receptor (H1R) has been determined in complex with its inverse agonist doxepin, a first-generation antihistamine. The crystal structure showed that doxepin sits deeply inside the ligand-binding pocket and predominantly interacts with residues highly conserved among other aminergic receptors. This binding mode is considered to result in the low selectivity of the first-generation antihistamines for H1R. The crystal structure also revealed the mechanism of receptor inactivation by the inverse agonist doxepin. On the other hand, the crystal structure elucidated the anion-binding site near the extracellular portion of the receptor. This site consists of residues not conserved among other aminergic receptors, which are specific for H1R. Docking simulation and biochemical experimentation demonstrated that a carboxyl group on the second-generation antihistamines interacts with the anion-binding site. These results imply that the anion-binding site is a key site for the development of highly selective antihistamine drugs.

  3. Structure of the human histamine H1 receptor complex with doxepin.

    Science.gov (United States)

    Shimamura, Tatsuro; Shiroishi, Mitsunori; Weyand, Simone; Tsujimoto, Hirokazu; Winter, Graeme; Katritch, Vsevolod; Abagyan, Ruben; Cherezov, Vadim; Liu, Wei; Han, Gye Won; Kobayashi, Takuya; Stevens, Raymond C; Iwata, So

    2011-06-22

    The biogenic amine histamine is an important pharmacological mediator involved in pathophysiological processes such as allergies and inflammations. Histamine H(1) receptor (H(1)R) antagonists are very effective drugs alleviating the symptoms of allergic reactions. Here we show the crystal structure of the H(1)R complex with doxepin, a first-generation H(1)R antagonist. Doxepin sits deep in the ligand-binding pocket and directly interacts with Trp 428(6.48), a highly conserved key residue in G-protein-coupled-receptor activation. This well-conserved pocket with mostly hydrophobic nature contributes to the low selectivity of the first-generation compounds. The pocket is associated with an anion-binding region occupied by a phosphate ion. Docking of various second-generation H(1)R antagonists reveals that the unique carboxyl group present in this class of compounds interacts with Lys 191(5.39) and/or Lys 179(ECL2), both of which form part of the anion-binding region. This region is not conserved in other aminergic receptors, demonstrating how minor differences in receptors lead to pronounced selectivity differences with small molecules. Our study sheds light on the molecular basis of H(1)R antagonist specificity against H(1)R. ©2011 Macmillan Publishers Limited. All rights reserved

  4. Functional pharmacology of H1 histamine receptors expressed in mouse preoptic/anterior hypothalamic neurons

    Science.gov (United States)

    Tabarean, I V

    2013-01-01

    BACKGROUND AND PURPOSE Histamine H1 receptors are highly expressed in hypothalamic neurons and mediate histaminergic modulation of several brain-controlled physiological functions, such as sleep, feeding and thermoregulation. In spite of the fact that the mouse is used as an experimental model for studying histaminergic signalling, the pharmacological characteristics of mouse H1 receptors have not been studied. In particular, selective and potent H1 receptor agonists have not been identified. EXPERIMENTAL APPROACH Ca2+ imaging using fura-2 fluorescence signals and whole-cell patch-clamp recordings were carried out in mouse preoptic/anterior hypothalamic neurons in culture. KEY RESULTS The H1 receptor antagonists mepyramine and trans-triprolidine potently antagonized the activation by histamine of these receptors with IC50 values of 0.02 and 0.2 μM respectively. All H1 receptor agonists studied had relatively low potency at the H1 receptors expressed by these neurons. Methylhistaprodifen and 2-(3-trifluoromethylphenyl)histamine had full-agonist activity with potencies similar to that of histamine. In contrast, 2-pyridylethylamine and betahistine showed only partial agonist activity and lower potency than histamine. The histamine receptor agonist, 6-[2-(4-imidazolyl)ethylamino]-N-(4-trifluoromethylphenyl)heptanecarboxamide (HTMT) had no agonist activity at the H1 receptors H1 receptors expressed by mouse preoptic/anterior hypothalamic neurons but displayed antagonist activity. CONCLUSIONS AND IMPLICATIONS Methylhistaprodifen and 2-(3-trifluoromethylphenyl)histamine were identified as full agonists of mouse H1 receptors. These results also indicated that histamine H1 receptors in mice exhibited a pharmacological profile in terms of agonism, significantly different from those of H1 receptors expressed in other species. PMID:23808378

  5. Histamine-HisCl1 Receptor Axis Regulates Wake-Promoting Signals in Drosophila melanogaster

    Science.gov (United States)

    Oh, Yangkyun; Jang, Donghoon; Sonn, Jun Young; Choe, Joonho

    2013-01-01

    Histamine and its two receptors, histamine-gated chloride channel subunit 1 (HisCl1) and ora transientless (Ort), are known to control photoreception and temperature sensing in Drosophila. However, histamine signaling in the context of neural circuitry for sleep-wake behaviors has not yet been examined in detail. Here, we obtained mutant flies with compromised or enhanced histamine signaling and tested their baseline sleep. Hypomorphic mutations in histidine decarboxylase (HDC), an enzyme catalyzing the conversion from histidine to histamine, caused an increase in sleep duration. Interestingly, hisCl1 mutants but not ort mutants showed long-sleep phenotypes similar to those in hdc mutants. Increased sleep duration in hisCl1 mutants was rescued by overexpressing hisCl1 in circadian pacemaker neurons expressing a neuropeptide pigment dispersing factor (PDF). Consistently, RNA interference (RNAi)-mediated depletion of hisCl1 in PDF neurons was sufficient to mimic hisCl1 mutant phenotypes, suggesting that PDF neurons are crucial for sleep regulation by the histamine-HisCl1 signaling. Finally, either hisCl1 mutation or genetic ablation of PDF neurons dampened wake-promoting effects of elevated histamine signaling via direct histamine administration. Taken together, these data clearly demonstrate that the histamine-HisCl1 receptor axis can activate and maintain the wake state in Drosophila and that wake-activating signals may travel via the PDF neurons. PMID:23844178

  6. Changes in Histidine Decarboxylase, Histamine N-Methyltransferase and Histamine Receptors in Neuropsychiatric Disorders

    NARCIS (Netherlands)

    Shan, Ling; Bao, Ai-Min; Swaab, Dick F

    2017-01-01

    Compared to other monoamine neurotransmitters, information on the association between the histaminergic system and neuropsychiatric disorders is scarce, resulting in a lack of histamine-related treatment for these disorders. The current chapter tries to combine information obtained from genetic

  7. The Quantum Nature of Drug-Receptor Interactions: Deuteration Changes Binding Affinities for Histamine Receptor Ligands.

    Directory of Open Access Journals (Sweden)

    Mojca Kržan

    Full Text Available In this article we report a combined experimental and computational study concerning the effects of deuteration on the binding of histamine and two other histaminergic agonists to 3H-tiotidine-labeled histamine H2 receptor in neonatal rat astrocytes. Binding affinities were measured by displacing radiolabeled tiotidine from H2 receptor binding sites present on cultured neonatal rat astrocytes. Quantum-chemical calculations were performed by employing the empirical quantization of nuclear motion within a cluster model of the receptor binding site extracted from the homology model of the entire H2 receptor. Structure of H2 receptor built by homology modelling is attached in the supporting information (S1 Table Experiments clearly demonstrate that deuteration affects the binding by increasing the affinity for histamine and reducing it for 2-methylhistamine, while basically leaving it unchanged for 4-methylhistamine. Ab initio quantum-chemical calculations on the cluster system extracted from the homology H2 model along with the implicit quantization of the acidic N-H and O-H bonds demonstrate that these changes in the binding can be rationalized by the altered strength of the hydrogen bonding upon deuteration known as the Ubbelohde effect. Our computational analysis also reveals a new mechanism of histamine binding, which underlines an important role of Tyr250 residue. The present work is, to our best knowledge, the first study of nuclear quantum effects on ligand receptor binding. The ligand H/D substitution is relevant for therapy in the context of perdeuterated and thus more stable drugs that are expected to enter therapeutic practice in the near future. Moreover, presented approach may contribute towards understanding receptor activation, while a distant goal remains in silico discrimination between agonists and antagonists based on the receptor structure.

  8. Pharmacological targeting of histamine H4 receptor in periodontal disease.

    Science.gov (United States)

    Prestifilippo, J P; Fernández-Solari, J; Martinel Lamas, D J; Rios, C E; Mohn, C; Perazzo, J C; Rivera, E S; Elverdin, J C; Medina, V A

    2016-07-01

    The objective of this study was to investigate whether histamine H4 receptor (H4 R) antagonists could prevent experimental periodontitis (EP)-induced histological, functional and inflammatory alterations in submandibular gland (SMG), periodontal bone and gingiva. Bilateral EP was induced for 2 weeks in anaesthetized male rats. The effect of systemic and local administration of H4 R antagonists (JNJ7777120, JNJ10191584) on histopathology and functionality of SMG, bone loss and gingival inflammation was evaluated. The subcutaneous administration of JNJ7777120 prevented periodontitis-induced SMG histological injury, reducing vacuolization and apoptosis and additionally reversed the increased prostaglandin E2 (PGE2) levels in SMG while it partially reversed the methacholine-induced salivation reduction produced by periodontitis. JNJ7777120 attenuated bone loss and the increased PGE2 levels and inflammatory infiltration in gingival tissue of rats with periodontitis. Finally, local administration of JNJ7777120 and JNJ10191584 was also beneficial for improving periodontal parameters. H4 receptor antagonists are able to ameliorate periodontitis-induced injury on SMG, gingival tissue and bone structure, suggesting that pharmacological targeting of H4 R could be an attractive strategy to improve periodontal health. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Anticonvulsant effects of isomeric nonimidazole histamine H3 receptor antagonists

    Directory of Open Access Journals (Sweden)

    Sadek B

    2016-11-01

    Full Text Available Bassem Sadek,1 Ali Saad,1 Johannes Stephan Schwed,2,3 Lilia Weizel,2 Miriam Walter,2 Holger Stark2,3 1Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates; 2Biocenter, Institute of Pharmaceutical Chemistry, Goethe University, Frankfurt, Germany; 3Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University, Düsseldorf, Germany Abstract: Phenytoin (PHT, valproic acid, and modern antiepileptic drugs (AEDs, eg, remacemide, loreclezole, and safinamide, are only effective within a maximum of 70%–80% of epileptic patients, and in many cases the clinical use of AEDs is restricted by their side effects. Therefore, a continuous need remains to discover innovative chemical entities for the development of active and safer AEDs. Ligands targeting central histamine H3 receptors (H3Rs for epilepsy might be a promising therapeutic approach. To determine the potential of H3Rs ligands as new AEDs, we recently reported that no anticonvulsant effects were observed for the (S-2-(4-(3-(piperidin-1-ylpropoxybenzylaminopropanamide (1. In continuation of our research, we asked whether anticonvulsant differences in activities will be observed for its R-enantiomer, namely, (R-2-(4-(3-(piperidin-1-ylpropoxybenzylaminopropaneamide (2 and analogs thereof, in maximum electroshock (MES-, pentylenetetrazole (PTZ-, and strychnine (STR-induced convulsion models in rats having PHT and valproic acid (VPA as reference AEDs. Unlike the S-enantiomer (1, the results show that animals pretreated intraperitoneally (ip with the R-enantiomer 2 (10 mg/kg were moderately protected in MES and STR induced models, whereas proconvulsant effect was observed for the same ligand in PTZ-induced convulsion models. However, animals pretreated with intraperitoneal doses of 5, 10, or 15 mg/kg of structurally bulkier (R-enantiomer (3

  10. The magnificent two: histamine and the H3 receptor as key modulators of striatal circuitry.

    Science.gov (United States)

    Rapanelli, Maximiliano

    2017-02-06

    Histaminergic dysfunction has been recently linked to tic disorders and to aberrant striatal function. There is a particular interest in the histamine 3 receptor (H3R) due to its clinical implications for treating multiple disorders and its high expression in the brain. Striatal histamine (HA) modulates through the H3R in complex ways the release of striatal neurotransmitters into this brain region. The H3R has been classically described to be coupled to Gi, although there is evidence that revealed that striatal H3R forms heteromers with the dopamine receptors 1 and 2 in the medium spiny neurons (MSNs) than changes this signaling. Moreover, new data described for the first time a complete, segregated and time dependent signaling after H3R activation in the two types of MSNs (D1R-MSNs and D2R-MSNs). The aim of this review is to update the role of HA and H3R in striatal function at a molecular and signaling levels. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Histamine and histamine type-2 receptor antagonists in psoriasis. Mechanisms and speculations

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen

    1991-01-01

    The findings that the immunosuppressant cyclosporine A (CsA) improves psoriasis raise the possibility that cellular immune processes may play a major role in the pathogenesis of this disease. It is broadly agreed that histamine released by mast cells is one of the molecules involved...... antagonists, previously reported to have a clinical effect on psoriasis. But randomised short-term studies have disclosed that these drugs have no beneficial or even an aggravating effect on the disease. This article reports on recent findings of improvement in psoriasis using high doses of the histamine-2...

  12. Histamine H4 receptors in normal conjunctiva and in vernal keratoconjunctivitis.

    Science.gov (United States)

    Leonardi, A; Di Stefano, A; Vicari, C; Motterle, L; Brun, P

    2011-10-01

    While it is known that histamine is the primary mediator of ocular allergy, the presence and distribution of histamine receptors are not well documented in the human eye. Our aim was to evaluate histamine receptor expression in normal and vernal keratoconjunctivitis conjunctiva. Mucosal biopsies were obtained from conjunctiva of healthy donors and from tarsal conjunctiva of vernal patients. Immunostaining and semi-quantitative reverse-transcriptase polymerase chain reaction for H(1), H(2), H(3), and H(4) receptors were performed. Histamine receptor expression was also evaluated in conjunctival cell cultures exposed to histamine, interleukin-4, interleukin-5, interferon-γ and tumor necrosis factor-α. Immunostaining for H(1) and H(2) receptors was slightly positive in normal and over-expressed in vernal tissues. H(3) receptors were rarely present in normal and inflamed conjunctiva. In striking contrast to control tissues, H(4) receptors were highly expressed in all inflamed tissues, particularly by stromal inflammatory cells. Semi-quantitative reverse-transcriptase polymerase chain reaction demonstrated an over-expression of H(1), H(2), and H(4) receptors in vernal vs control tissues. Notably, H(4) receptors were five times more expressed in vernal vs control tissues. In cell cultures, H(2) receptor expression was stimulated eight times the normal levels by interleukin-4 and three times by histamine, but the H(4) receptor was only slightly affected by stimulation with these mediators. Increased expression of H1, and particularly of H(2) and H(4) receptors in vernal keratoconjunctival tissues indicate their important role in the pathogenesis of this disease. H(4) receptors may be a target in the treatment of allergic inflammation. © 2011 John Wiley & Sons A/S.

  13. Possible role of histamine in pathogenesis of autoimmune diseases: implications for immunotherapy with histamine-2 receptor antagonists

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen; Hammer, J H

    1992-01-01

    the possibility, that histamine is one of the molecules involved in pathogenesis of autoimmune diseases. T cell mediated regulation and suppression of autoreactive T cells seem to be ineffective in controlling the enhanced immune reaction in patients where the discrimination between self and non-self is changed....... A consequence of this may be induction of interferon-gamma (IFN-g) production and release by cytotoxic T cells, subsequently leading to expression of MHC II molecules on non-immune tissues. As immunotherapy may be of value in some autoimmune diseases the use of histamine-2 receptor antagonists should...... autoantigens and major histocompatibility complex (MHC) class II restriction molecules presented by non-immune, aberrant cells, subsequently leading to damage on healthy tissues. Psoriasis is suggested to be an autoimmune disease and in severe, uncontrollable psoriasis CsA and Mx are of value in reducing...

  14. Effects of high levels of dietary zinc oxide on ex vivo epithelial histamine response and investigations on histamine receptor action in the proximal colon of weaned piglets.

    Science.gov (United States)

    Kröger, S; Pieper, R; Aschenbach, J R; Martin, L; Liu, P; Rieger, J; Schwelberger, H G; Neumann, K; Zentek, J

    2015-11-01

    The aim of the study was to identify the effect of high dietary zinc oxide (ZnO) levels on the histamine-induced secretory-type response and histamine metabolism in the porcine proximal colon. After weaning at d 26, 3 diets with low (LZn), normal (NZn), and high (HZn) concentrations of zinc (57, 164, or 2,425 mg/kg) were fed to a total of 120 piglets. Digesta and tissue samples were taken from the ascending colon after 7 ± 1, 14 ± 1, 21 ± 1, and 28 ± 1 d. Partially stripped tissue was mounted in Ussing chambers, and histamine was applied either to the serosal or mucosal compartments. Tissue was pretreated with or without aminoguanidine and amodiaquine to block the histamine-degrading enzymes diamine oxidase (DAO) and histamine -methyltransferase (HMT), respectively. Gene expression and catalytic activity of DAO and HMT in the tissue were analyzed. The numbers of mast cells were determined in tissue samples, and histamine concentration was measured in the colon digesta. Colon tissue from another 12 piglets was used for functional studies on histamine H and H receptors by using the neuronal conduction blocker tetrodotoxin (TTX) and the H and H receptor blocker chloropyramine and famotidine, respectively. After serosal histamine application to colonic tissue in Ussing chambers, the change of short-circuit current (Δ) was not affected by pretreatment and was not different between Zn feeding groups. The Δ after mucosal histamine application was numerically lower ( = 0.168) in HZn compared to LZn and NZn pigs. Mast cell numbers increased from 32 to 46 d of life ( < 0.05). Further studies elucidated that the serosal histamine response was partly inhibited by chloropyramine or famotidine ( < 0.01). The response to mucosal histamine tended to be decreased when chloropyramine but not famotidine was applied from either the serosal or the mucosal side ( = 0.055). Tetrodotoxin alone or in combination with chloropyramine resulted in a similar reduction in the mucosal

  15. Histamina, receptores de histamina e anti-histamínicos: novos conceitos Histamine, histamine receptors and antihistamines: new concepts

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    Paulo Ricardo Criado

    2010-04-01

    Full Text Available As drogas com ação anti-histamínica estão entre as medicações mais comumente prescritas na prática dermatológica diária, tanto em adultos como em crianças. Este artigo aborda os novos conceitos da função dos receptores de histamina (receptores H1 e discute os efeitos anti-inflamatórios dessas drogas. A segunda geração de anti-histamínicos difere da primeira geração devido a sua elevada especificidade e afinidade pelos receptores H1 periféricos e devido a seu menor efeito no sistema nervoso central, tendo como resultado menores efeitos sedativos. Embora a eficácia dos diferentes anti-histamínicos H1 (anti-H1 no tratamento de doentes alérgicos seja similar, mesmo quando se comparam anti-H1 de primeira e de segunda geração, eles são muito diferentes em termos de estrutura química, farmacologia e propriedades tóxicas. Consequentemente o conhecimento de suas características farmacocinéticas e farmacodinâmicas é importante para a melhor prática médica, especialmente em gestantes, crianças, idosos e doentes com comorbidades.Drugs with antihistamine action are the most commonly prescribed medication in daily dermatologic practice, both to adults and children. This article addresses new concepts of the role of histamine receptors (H1 receptors and discusses the anti-inflammatory effects of these drugs. Second generation antihistamines differs from first generation because of their high specificity and affinity for peripheral H1-receptors. Second generation antihistamines are also less likely to produce sedation because they have less effect on the central nervous system. Although the efficacy of the various H1-antihistamines in the treatment of allergic patients is similar, even when comparing first- and second-generation drugs, these drugs are still very different in terms of their chemical structure, pharmacology and toxic properties. Consequently, knowledge of their pharmacokinetic and pharmacodynamic characteristics

  16. Expression and localization of histamine H1, H2, and H3 receptors in rat olfactory epithelium.

    Science.gov (United States)

    Yu, Chao; Li, Li; Xia, Qingjie; Tang, Yuedi

    2017-10-01

    Histamine is an important chemical mediator in the development of allergic rhinitis and plays a key role in eliciting the nasal symptoms of the disorder. Histamine may also affect smell as a neurotransmitter. However, whether histamine receptors are present in the mammalian olfactory epithelium has not yet been examined. The aim of this study was to investigate the expression and distribution of histamine H1, H2, and H3 receptors in rat olfactory epithelium. Real-time quantitative PCR and immunohistochemical staining were performed to examine the mRNA level and protein expression and localization of histamine receptors (H1, H2, and H3) in rat olfactory epithelium. We demonstrated that mRNAs encoding histamine H1, H2, and H3 receptors were detected in rat olfactory epithelium. Immunohistochemistry also showed strong positive staining for these receptors. Co-localization of histamine H1, H2, and H3 receptors with olfactory mature protein revealed that these three histamine receptors were mainly localized in olfactory receptor neurons. These findings indicate that histamine H1, H2, and H3 receptors are present in rat olfactory epithelium and may play a physiological role in olfactory transmission. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Histamine-2 receptor antagonists as immunomodulators: new therapeutic views?

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen

    1996-01-01

    Considerable evidence has emerged to suggest that histamine participates in the regulation of the inflammatory response, immune reaction, coagulation cascade, and cardiovascular function. Furthermore, histamine may play a major role in the growth of normal and malignant tissue as a regulator of p...... antagonists as adjuvant single drugs to reduce trauma-, blood transfusion- and sepsis-induced immunosuppression has led to research in combined treatment regimens in major surgery, particularly, of patients operated on for malignant diseases....

  18. Protean agonism at histamine H3 receptors in vitro and in vivo.

    Science.gov (United States)

    Gbahou, Florence; Rouleau, Agnès; Morisset, Séverine; Parmentier, Régis; Crochet, Sylvain; Lin, Jian-Sheng; Ligneau, Xavier; Tardivel-Lacombe, Joël; Stark, Holger; Schunack, Walter; Ganellin, C Robin; Schwartz, Jean-Charles; Arrang, Jean-Michel

    2003-09-16

    G protein-coupled receptors (GPCRs) are allosteric proteins that adopt inactive (R) and active (R*) conformations in equilibrium. R* is promoted by agonists or occurs spontaneously, leading to constitutive activity of the receptor. Conversely, inverse agonists promote R and decrease constitutive activity. The existence of another pharmacological entity, referred to as "protean" agonists (after Proteus, the Greek god who could change shape), was assumed on theoretical grounds. It was predicted from the existence of constitutive activity that a same ligand of this class could act either as an agonist or an inverse agonist at the same GPCR. Here, we show that proxyfan, a high-affinity histamine H3-receptor ligand, acts as a protean agonist at recombinant H3 receptors expressed in the same Chinese hamster ovary cells. In support of the physiological relevance of the process, we show that proxyfan also behaves as a protean agonist at native H3 receptors known to display constitutive activity. On neurochemical and behavioral responses in rodents and cats, proxyfan displays a spectrum of activity ranging from full agonism to full inverse agonism. Thus, protean agonism demonstrates the existence of ligand-directed active states LR* different from, and competing with, constitutively active states R* of GPCRs, and defines a pharmacological entity with important therapeutic implications.

  19. Protean agonism at histamine H3 receptors in vitro and in vivo

    Science.gov (United States)

    Gbahou, Florence; Rouleau, Agnès; Morisset, Séverine; Parmentier, Régis; Crochet, Sylvain; Lin, Jian-Sheng; Ligneau, Xavier; Tardivel-Lacombe, Joël; Stark, Holger; Schunack, Walter; Ganellin, C. Robin; Schwartz, Jean-Charles; Arrang, Jean-Michel

    2003-01-01

    G protein-coupled receptors (GPCRs) are allosteric proteins that adopt inactive (R) and active (R*) conformations in equilibrium. R* is promoted by agonists or occurs spontaneously, leading to constitutive activity of the receptor. Conversely, inverse agonists promote R and decrease constitutive activity. The existence of another pharmacological entity, referred to as “protean” agonists (after Proteus, the Greek god who could change shape), was assumed on theoretical grounds. It was predicted from the existence of constitutive activity that a same ligand of this class could act either as an agonist or an inverse agonist at the same GPCR. Here, we show that proxyfan, a high-affinity histamine H3-receptor ligand, acts as a protean agonist at recombinant H3 receptors expressed in the same Chinese hamster ovary cells. In support of the physiological relevance of the process, we show that proxyfan also behaves as a protean agonist at native H3 receptors known to display constitutive activity. On neurochemical and behavioral responses in rodents and cats, proxyfan displays a spectrum of activity ranging from full agonism to full inverse agonism. Thus, protean agonism demonstrates the existence of ligand-directed active states LR* different from, and competing with, constitutively active states R* of GPCRs, and defines a pharmacological entity with important therapeutic implications. PMID:12960366

  20. Anticonvulsive effect of nonimidazole histamine H3 receptor antagonists.

    Science.gov (United States)

    Sadek, Bassem; Kuder, Kamil; Subramanian, Dhanasekaran; Shafiullah, Mohamed; Stark, Holger; Lażewska, Dorota; Adem, Abdu; Kieć-Kononowicz, Katarzyna

    2014-06-01

    To determine the potential of histamine H3 receptor (H3R) ligands as new antiepileptic drugs (AEDs), aromatic ether, and diether derivatives (1-12) belonging to the nonimidazole class of ligands, with high in-vitro binding affinity at human H3R, were tested for their in-vivo anticonvulsive activity in the maximal electroshock (MES)-induced and pentylenetetrazole (PTZ)-kindled seizure models in rats. The anticonvulsive effects of a systemic injection of 1-12 on MES-induced and PTZ-kindled seizures were evaluated against the reference AED phenytoin (PHT) and the structurally related H3R antagonist/inverse agonist pitolisant (PIT). Among the most promising ligands 2, 4, 5, and 11, there was a significant and dose-dependent reduction in the duration of tonic hind limb extension (THLE) in MES-induced seizure subsequent to administration of 4 and 5 [(5, 10, and 15 mg/kg, intraperitoneally (i.p.)]. The protective effects observed for the 1-(3-(3-(4-chlorophenyl)propoxy)propyl)-3-methylpiperidine derivative 11 at 10 mg/kg, i.p. were significantly greater than those of PIT, and were reversed by pretreatment with the central nervous system penetrant H1R antagonist pyrilamine (PYR) (10 mg/kg). Moreover, the protective action of the reference AED PHT, at a dose of 5 mg/kg (without considerable protection in the MES model), was significantly augmented when coadministered with derivative 11 (5 mg/kg, i.p.). Surprisingly, pretreatment with derivative 7 (10 mg/kg, i.p.), an ethylphenoxyhexyl-piperidine derivative without considerable protection in the MES model, potently altered PTZ-kindled seizure, significantly prolonged myoclonic latency time, and clearly shortened the total seizure time when compared with control, PHT, and PIT. These interesting results highlight the potential of H3R ligands as new AEDs or as adjuvants to available AED therapeutics.

  1. Effects of histamine H1 receptor signaling on glucocorticoid receptor activity. Role of canonical and non-canonical pathways

    NARCIS (Netherlands)

    Zappia, C.D.; Granja-Galeano, G.; Fernández, N.; Shayo, C.; Davio, C.; Fitzsimons, C.P.; Monczor, F.

    2015-01-01

    Histamine H1 receptor (H1R) antagonists and glucocorticoid receptor (GR) agonists are used to treat inflammatory conditions such as allergic rhinitis, atopic dermatitis and asthma. Consistent with the high morbidity levels of such inflammatory conditions, these receptors are the targets of a vast

  2. The Effects of Histamine H3 Receptors on Contractile Responses on Rat Gastric Fundus

    Directory of Open Access Journals (Sweden)

    Aşkın Hekimoğlu

    2006-01-01

    Full Text Available The aim of this study is to determine the effects of histamine receptors on the gastrointestinal system smooth muscle contractions and the role of histamine H3 receptors on these effects. İsolated rat gastric fundus preparations were hanged on isolated organ bath and histamine receptor agonist and anthagonists were added to the bath solution and the electrical field stimulation-induced contractile responses were evaluated. In our study groups after blocking one of the histamine receptors H1, H2,H3; contractile responses were observed. Then, other two receptors were blocked one by one or combination of them to observe the changes on the contractile responses given to the electrical stimulation .To blocke histamine receptors pyrilamine (10-6м as H1 receptor blocker, famotidine (10-6м as H2 receptor blocker and thioperamide (10-5м as H3 receptor blocker and various combination of them were used. All groups were treated with H3 receptor anthagonist thioperamide (10-5м and agonist (R-α-methylhistamine (RMHA on 10-8, 10-7, 10-6 ve 10-5 molar concentrations cumulatively to observe its mediator effects on contractile responses. We suggested that (R-α-methylhistamine mediates the inhibition on the contractile effects of rat gastric fundus. This conclusion was supported by these findings: a the selective agonists (RMHA caused a dumping of the contractile effect of acetylcholine; b the effect of (RMHA was prevented by the selective H3 receptor antagonist thioperamide.

  3. Human memory Th17 cells express a functional histamine H4 receptor.

    Science.gov (United States)

    Mommert, Susanne; Gschwandtner, Maria; Koether, Brigitta; Gutzmer, Ralf; Werfel, Thomas

    2012-01-01

    The histamine H4 receptor is functionally expressed on CD4(+) T cells and in particular on human CD4(+) Th2-polarized T cells. Interleukin (IL)-17-producing T cells (Th17 cells) represent a newly defined major CD4(+) T-cell subset, having been identified in psoriatic plaques and in acute skin lesions of atopic dermatitis where histamine is also present in high concentrations. To elucidate the role of the histamine H4 receptor (H4R) on these effector T cells, we polarized human memory T cells into Th17 cells. Further, we investigated H4R expression and assessed its function by real-time PCR, by a cytokine secretion assay of IL-17, and by electrophoretic mobility shift assay of activating protein-1 (AP-1). We show that Th17 cells polarized by IL-1β together with IL-23 express the H4R on mRNA and protein level. Additionally, we identified IL-17-positive cells in psoriatic skin lesions. The IL-17-positive lymphocytes were all positive also for functional H4R. Stimulation with histamine or a H4R agonist increased the production of IL-17 and induced activating protein-1 in Th17 cells. In inflammatory skin diseases with enhanced histamine release, such as psoriasis and atopic dermatitis, histamine might foster the immunomodulatory potency of skin-infiltrating Th17 cells. Copyright © 2012 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  4. Monocyclic and Fused Azines and Azoles as Histamine H4 Receptor Ligands.

    Science.gov (United States)

    Lażewska, Dorota; Domínguez-Álvarez, Enrique; Kamińska, Katarzyna; Kuder, Kamil; Kieć-Kononowicz, Katarzyna

    2016-01-01

    The histamine H4 receptor has stood out since its discovery and identification in 2000 as an important target in the search for potential new drugs for the treatment of inflammatory and allergic diseases such as rhinitis, pruritus and asthma. Thus, in the last decade, both industry and academia have performed an intensive and productive search for new ligands of this newest subtype of histamine receptor. The most promising compounds found include monocyclic and fused azines, and azoles such as bispyrimidines, di- and triaminopyrimidines, quinazolines, imidazoles, indoles, benzimidazoles and benzazoles. The aim of this review is to give an insight into the current state of the art in the field of histamine H4 receptor research, focusing mainly on the last five years.

  5. Cholinesterase inhibitory activity of chlorophenoxy derivatives-Histamine H3 receptor ligands.

    Science.gov (United States)

    Łażewska, Dorota; Jończyk, Jakub; Bajda, Marek; Szałaj, Natalia; Więckowska, Anna; Panek, Dawid; Moore, Caitlin; Kuder, Kamil; Malawska, Barbara; Kieć-Kononowicz, Katarzyna

    2016-08-15

    In recent years, multitarget-directed ligands have become an interesting strategy in a search for a new treatment of Alzheimer's disease. Combination of both: a histamine H3 receptor antagonist/inverse agonist and a cholinesterases inhibitor in one molecule could provide a new therapeutic opportunity. Here, we present biological evaluation of histamine H3 receptor ligands-chlorophenoxyalkylamine derivatives against cholinesterases: acetyl- and butyrylcholinesterase. The target compounds showed cholinesterase inhibitory activity in a low micromolar range. The most potent in this group was 1-(7-(4-chlorophenoxy)heptyl)homopiperidine (18) inhibiting the both enzymes (EeAChE IC50=1.93μM and EqBuChE IC50=1.64μM). Molecular modeling studies were performed to explain the binding mode of 18 with histamine H3 receptor as well as with cholinesterases. Copyright © 2016. Published by Elsevier Ltd.

  6. Asp73-dependent and -independent regulation of the affinity of ligands for human histamine H1 receptors by Na().

    Science.gov (United States)

    Hishinuma, Shigeru; Kosaka, Kiyoe; Akatsu, Chizuru; Uesawa, Yoshihiro; Fukui, Hiroyuki; Shoji, Masaru

    2017-03-15

    The affinity of ligands for G-protein-coupled receptors (GPCRs) is allosterically regulated by Na(+) via a highly conserved aspartate residue (Asp(2.50)) in the second transmembrane domain of GPCRs. In the present study, we examined the Na(+)-mediated regulation of the affinity of ligands for Gq/11-protein-coupled human histamine H1 receptors in Chinese hamster ovary cells. The affinities of 3 agonists and 20 antihistamines were evaluated by their displacement curves against the binding of [(3)H]-mepyramine to membrane preparations in the presence or absence of 100mM NaCl. The affinities of most drugs including histamine, an agonist, and d-chlorpheniramine, a first-generation antihistamine, were reduced by NaCl, with the extent of NaCl-mediated changes varying widely between drugs. In contrast, the affinities of some second-generation antihistamines such as fexofenadine were increased by NaCl. These changes were retained in intact cells. The mutation of Asp(2.50) (Asp73) to asparagine abrogated NaCl-induced reductions in affinities for histamine and d-chlorpheniramine, but not NaCl-induced increases in the affinity for fexofenadine. Quantitative structure-activity relationship (QSAR) analyses showed that these Na(+)-mediated changes were explained and predicted by a combination of the molecular energies and implicit solvation energies of the compounds. These results suggest that Na(+) diversely regulates the affinity of ligands for H1 receptors from the extracellular sites of receptors via Asp73-dependent and -independent mechanisms in a manner that depends on the physicochemical properties of ligands. These results may contribute to a deeper understanding of the fundamental mechanisms by which the affinity of ligands for their receptors is allosterically regulated by Na(+). Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Prejunctional histamine H-3-receptors inhibit electrically evoked endogenous noradrenaline overflow in the portal vein of freely moving rats

    NARCIS (Netherlands)

    Smit, J; Coppes, Rob P.; van Tintelen, Eric J.J.; Roffel, A.F.; Zaagsma, Johan

    The effects of intra-arterial injection of different doses of the selective histamine H-3-receptor agonist R-alpha-methylhistamine and the selective histamine H-3-receptor antagonist thioperamide on basal and electrically evoked noradrenaline overflow in the portal vein as well as on mean arterial

  8. Changes in Histamine Receptors (H1, H2, and H3 Expression in Rat Medial Vestibular Nucleus and Flocculus after Unilateral Labyrinthectomy: Histamine Receptors in Vestibular Compensation.

    Directory of Open Access Journals (Sweden)

    Liuqing Zhou

    Full Text Available Vestibular compensation is the process of behavioral recovery following peripheral vestibular lesion. In clinics, the histaminergic medicine is the most widely prescribed for the treatment of vertigo and motion sickness, however, the molecular mechanisms by which histamine modulates vestibular function remain unclear. During recovery from the lesion, the modulation of histamine receptors in the medial vestibular nucleus (MVN and the flocculus may play an important role. Here with the means of quantitative real-time PCR, western blotting and immunohistochemistry, we studied the expression of histamine receptors (H1, H2, and H3 in the bilateral MVN and the flocculus of rats on the 1st, 3rd, and 7th day following unilateral labyrinthectomy (UL. Our results have shown that on the ipsi-lesional flocculus the H1, H2 and H3 receptors mRNA and the protein increased significantly on the 1st and 3rd day, with compare of sham controls and as well the contralateral side of UL. However, on the 7th day after UL, this expression returned to basal levels. Furthermore, elevated mRNA and protein levels of H1, H2 and H3 receptors were observed in the ipsi-lesional MVN on the 1st day after UL compared with sham controls and as well the contralateral side of UL. However, this asymmetric expression was absent by the 3rd post-UL. Our findings suggest that the upregulation of histamine receptors in the MVN and the flocculus may contribute to rebalancing the spontaneous discharge in bilateral MVN neurons during vestibular compensation.

  9. Histamine induces microglia activation and dopaminergic neuronal toxicity via H1 receptor activation.

    Science.gov (United States)

    Rocha, Sandra M; Saraiva, Tatiana; Cristóvão, Ana C; Ferreira, Raquel; Santos, Tiago; Esteves, Marta; Saraiva, Cláudia; Je, Goun; Cortes, Luísa; Valero, Jorge; Alves, Gilberto; Klibanov, Alexander; Kim, Yoon-Seong; Bernardino, Liliana

    2016-06-04

    Histamine is an amine widely known as a peripheral inflammatory mediator and as a neurotransmitter in the central nervous system. Recently, it has been suggested that histamine acts as an innate modulator of microglial activity. Herein, we aimed to disclose the role of histamine in microglial phagocytic activity and reactive oxygen species (ROS) production and to explore the consequences of histamine-induced neuroinflammation in dopaminergic (DA) neuronal survival. The effect of histamine on phagocytosis was assessed both in vitro by using a murine N9 microglial cell line and primary microglial cell cultures and in vivo. Cells were exposed to IgG-opsonized latex beads or phosphatidylserine (PS) liposomes to evaluate Fcγ or PS receptor-mediated microglial phagocytosis, respectively. ROS production and protein levels of NADPH oxidases and Rac1 were assessed as a measure of oxidative stress. DA neuronal survival was evaluated in vivo by counting the number of tyrosine hydroxylase-positive neurons in the substantia nigra (SN) of mice. We found that histamine triggers microglial phagocytosis via histamine receptor 1 (H1R) activation and ROS production via H1R and H4R activation. By using apocynin, a broad NADPH oxidase (Nox) inhibitor, and Nox1 knockout mice, we found that the Nox1 signaling pathway is involved in both phagocytosis and ROS production induced by histamine in vitro. Interestingly, both apocynin and annexin V (used as inhibitor of PS-induced phagocytosis) fully abolished the DA neurotoxicity induced by the injection of histamine in the SN of adult mice in vivo. Blockade of H1R protected against histamine-induced Nox1 expression and death of DA neurons in vivo. Overall, our results highlight the relevance of histamine in the modulation of microglial activity that ultimately may interfere with neuronal survival in the context of Parkinson's disease (PD) and, eventually, other neurodegenerative diseases which are accompanied by microglia

  10. TRPV1 and PLC Participate in Histamine H4 Receptor-Induced Itch

    Directory of Open Access Journals (Sweden)

    Tunyu Jian

    2016-01-01

    Full Text Available Histamine H4 receptor has been confirmed to play a role in evoking peripheral pruritus. However, the ionic and intracellular signaling mechanism of activation of H4 receptor on the dorsal root ganglion (DRG neurons is still unknown. By using cell culture and calcium imaging, we studied the underlying mechanism of activation of H4 receptor on the DRG neuron. Immepip dihydrobromide (immepip—a histamine H4 receptor special agonist under cutaneous injection—obviously induced itch behavior of mice. Immepip-induced scratching behavior could be blocked by TRPV1 antagonist AMG9810 and PLC pathway inhibitor U73122. Application of immepip (8.3–50 μM could also induce a dose-dependent increase in intracellular Ca2+ (Ca2+i of DRG neurons. We found that 77.8% of the immepip-sensitized DRG neurons respond to the TRPV1 selective agonist capsaicin. U73122 could inhibit immepip-induced Ca2+ responses. In addition, immepip-induced Ca2+i increase could be blocked by ruthenium red, capsazepine, and AMG9810; however it could not be blocked by TRPA1 antagonist HC-030031. These results indicate that TRPV1 but not TRPA1 is the important ion channel to induce the DRG neurons’ responses in the downstream signaling pathway of histamine H4 receptor and suggest that TRPV1 may be involved in the mechanism of histamine-induced itch response by H4 receptor activation.

  11. Differences in histamine H1 and H2 receptor responses in several rabbit arteries

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    Robinson, C.P.; Maxson, S.

    1982-06-01

    Responses of helically cut segments from six different rabbit arteries to the selective histamine H1 receptor agonist 2-pyridylethylamine (PEA) and, in strips contracted by 10-4 M phenylephrine, to the selective histamine H2 agonist dimaprit have been determined. 10-3 M PEA contracted the renal artery, 96 +/- 2%; mesenteric artery, 92 +/- 2%; coeliac artery, 88 +/- 11% aorta 75 +/- 4%' ear artery 64 +/- 10% and pulmonary artery 48 +/- 5% of the maximal contraction to norepinephrine. 10-3 M dimaprit relaxed the phenylephrine contracted ear artery 48 +/- 8%; renal artery, 43 +/- 8%; coeliac artery 41 +/- 8%; mesenteric artery 36 +/- 5%; aorta 16 +/- 3%; and pulmonary artery 11 +/- 1% of the initial contractile tension. Strips in which histamine H1 receptors are blocked by 7 X 10-6 M mepyramine which are contracted by phenylephrine are partially relaxed by histamine. Cooling these strips markedly enhanced relaxations of the mesenteric and coeliac arteries but not those of the other four vessels. Exposure of the strips to dibenamine potentiated relaxations of all of the arteries except the ear artery and pulmonary artery. Thus there is heterogeneity among the arteries in their responses to histamine H1 and H2 receptor activation.

  12. Cardiac mast cells regulate myocyte ANP release via histamine H2 receptor in beating rabbit atria.

    Science.gov (United States)

    Li, Dan; Wen, Jin Fu; Jin, Jing Yu; Quan, He Xiu; Cho, Kyung Woo

    2009-06-05

    It has been shown that histamine inhibits atrial natriuretic peptide (ANP) release. Because cardiac mast cells are the principal source of histamine in the heart, we hypothesized that cardiac mast cells are involved in the regulation of atrial ANP release. To test the hypothesis, experiments were performed in perfused beating rabbit atria allowing atrial pacing and measurements of changes in atrial stroke volume, intraatrial pulse pressure and myocyte ANP release. Mast cell degranulation with Compound 48/80 decreased atrial myocyte ANP release, and the response was blocked by a selective histamine H(2) receptor blocker, cimetidine, indicating that histamine was responsible for the decrease in ANP release. Mast cell stabilization with cromolyn blocked the Compound 48/80-induced decrease in ANP release. These data suggest that mast cell-derived histamine is involved in the regulation of cardiac ANP release. Thus, the cardiac mast cell-cardiomyocyte communication via the histamine-ANP pathway may implicate in the cardiac disorder associated with mast cell degranulation such as in acute coronary syndrome or cardiac hypertrophy.

  13. Ca2+-dependent down-regulation of human histamine H1receptors in Chinese hamster ovary cells.

    Science.gov (United States)

    Hishinuma, Shigeru; Komazaki, Hiroshi; Tsukamoto, Hayato; Hatahara, Hirokazu; Fukui, Hiroyuki; Shoji, Masaru

    2018-01-01

    G q/11 protein-coupled human histamine H 1 receptors in Chinese hamster ovary cells stimulated with histamine undergo clathrin-dependent endocytosis followed by proteasome/lysosome-mediated down-regulation. In this study, we evaluated the effects of a sustained increase in intracellular Ca 2+ concentrations induced by a receptor-bypassed stimulation with ionomycin, a Ca 2+ ionophore, on the endocytosis and down-regulation of H 1 receptors in Chinese hamster ovary cells. All cellular and cell-surface H 1 receptors were detected by the binding of [ 3 H]mepyramine to intact cells sensitive to the hydrophobic and hydrophilic H 1 receptor ligands, mepyramine and pirdonium, respectively. The pretreatment of cells with ionomycin markedly reduced the mepyramine- and pirdonium-sensitive binding sites of [ 3 H]mepyramine, which were completely abrogated by the deprivation of extracellular Ca 2+ and partially by a ubiquitin-activating enzyme inhibitor (UBEI-41), but were not affected by inhibitors of calmodulin (W-7 or calmidazolium) and protein kinase C (chelerythrine or GF109203X). These ionomycin-induced changes were also not affected by inhibitors of receptor endocytosis via clathrin (hypertonic sucrose) and caveolae/lipid rafts (filipin or nystatin) or by inhibitors of lysosomes (E-64, leupeptin, chloroquine, or NH 4 Cl), proteasomes (lactacystin or MG-132), and a Ca 2+ -dependent non-lysosomal cysteine protease (calpain) (MDL28170). Since H 1 receptors were normally detected by confocal immunofluorescence microscopy with an antibody against H 1 receptors, even after the ionomycin treatment, H 1 receptors appeared to exist in a form to which [ 3 H]mepyramine was unable to bind. These results suggest that H 1 receptors are apparently down-regulated by a sustained increase in intracellular Ca 2+ concentrations with no process of endocytosis and lysosomal/proteasomal degradation of receptors. © 2017 International Society for Neurochemistry.

  14. Calyx and dimorphic neurons of mouse Scarpa's ganglion express histamine H3 receptors

    Directory of Open Access Journals (Sweden)

    Zucca Gianpiero

    2009-06-01

    Full Text Available Abstract Background Histamine-related drugs are commonly used in the treatment of vertigo and related vestibular disorders. The site of action of these drugs however has not been elucidated yet. Recent works on amphibians showed that histamine H3 receptor antagonists, e.g. betahistine, inhibit the afferent discharge recorded from the vestibular nerve. To assess the expression of H3 histamine receptors in vestibular neurons, we performed mRNA RT-PCR and immunofluorescence experiments in mouse Scarpa's ganglia. Results RT-PCR analysis showed the presence of H3 receptor mRNA in mouse ganglia tissue. H3 protein expression was found in vestibular neurons characterized by large and roundish soma, which labeled for calretinin and calbindin. Conclusion The present results are consistent with calyx and dimorphic, but not bouton, afferent vestibular neurons expressing H3 receptors. This study provides a molecular substrate for the effects of histamine-related antivertigo drugs acting on (or binding to H3 receptors, and suggest a potential target for the treatment of vestibular disorders of peripheral origin.

  15. Role of H1 receptors and P-selectin in histamine-induced leukocyte rolling and adhesion in postcapillary venules.

    Science.gov (United States)

    Asako, H; Kurose, I; Wolf, R; DeFrees, S; Zheng, Z L; Phillips, M L; Paulson, J C; Granger, D N

    1994-04-01

    The objective of this study was to define the nature, magnitude, and mechanisms of histamine-induced leukocyte-endothelial cell interactions in postcapillary venules of the rat mesentery using intravital microscopic techniques. Superfusion of the mesentery with histamine (10(-7)-10(-5) M) resulted in a dose-related increase in the number of rolling leukocytes, a reduction in rolling velocity, and an increased clearance of FITC-labeled rat albumin from blood to superfusate. The histamine-induced recruitment of rolling leukocytes and increased albumin clearance were prevented by histamine H1 (hydroxyzine, diphenhydramine) but not H2 (cimetidine) receptor antagonists. Because histamine induces expression of the adhesion molecule P-selectin in cultured endothelial cells, a monoclonal antibody directed against rat P-selectin and soluble sialyl-LewisX oligosaccharide (the carbohydrate ligand to P-selectin) were also tested as inhibitors. Both were effective in preventing the histamine-induced recruitment of rolling leukocytes, but neither agent attenuated the increased albumin clearance. These observations suggest that (a) histamine recruits rolling leukocytes and increases albumin leakage in postcapillary venules via H1 receptor activation, (b) histamine-induced recruitment of rolling leukocytes is mediated in part by P-selectin expressed on the endothelial cell surface, and (c) the histamine-induced vascular albumin leakage is unrelated to leukocyte-endothelial cell adhesion. Our results are consistent with the view that histamine may act as a mediator of acute inflammatory reactions.

  16. Pharmacological properties of cardiovascular histamine H1 receptor binding sites: characterisation with 2-phenylhistamines.

    Science.gov (United States)

    Carman-Krzan, M; Krzan, M; Schunack, W

    1997-04-01

    We determined and compared the molecular properties of histamine H1 receptor binding sites in bovine thoracic aorta smooth muscle and guinea pig myocardial membranes from ventricles with saturation and inhibition binding assay, using 3H-mepyramine to label the receptor and specific and selective H1 receptor agonists of the 2-phenylhistamine group as displacers of specific 3H-mepyramine binding. 3H-mepyramine binds in a saturable manner to a homogenous population of binding sites with a K(D) of 5.6 nM and a Bmax of 57 fmol/mg of protein in bovine aorta vascular smooth muscle membranes, whereas in the guinea pig myocardium high and low affinity 3H-mepyramine binding sites exist having the following molecular characteristics: a K(D) of 1.6 nM and a Bmax of 99 fmol/mg of protein (high affinity site) and a K(D) 15.0 nM and a Bmax of 466 fmol/mg of protein (low affinity site). Halogenated 2-phenylhistamines: 2-(3-fluoro-) (2-FPH), 2-(3-trifluoromethyl-) (2-triFMPH), 2-(3-chloro-) (2-CPH), 2-(3-bromo-) (2-BPH) and 2-(3-iodophenyl)histamine (2-IPH), which showed high selectivity and potency for H1 receptors in the functional pharmacological studies, were potent inhibitors of specific radioligand binding in comparison with histamine and parent nonhalogenated 2-phenylhistamine (2-PH). Their rank order of potencies and affinities differ significantly for the vascular and cardiac H1 receptor binding sites: Specific 3H-mepyramine binding to H1 receptors in bovine vascular smooth muscle membranes was displaced in a biphasic manner by 2-(3-fluoro-), 2-(3-trifluoromethyl-), 2-(3-chloro-), 2-(3-bromo-), 2-(3-iodophenyl)histamine and histamine. In guinea pig ventricular myocardium the rank order was 2-(3-iodo-), 2-(3-bromo-), histamine, 2-(3-chloro-), and 2-(3-fluorophenyl)histamine showing better correlation with the lipophilicity of the derivatives than in vascular tissue (order of lipophilicity: 2-triFMPH >2-IPH >2-BPH >2-CPH >2-FPH >2-PH). Displacement of the radioligand binding

  17. Histamine 1 Receptor Blockade Enhances Eosinophil-Mediated Clearance of Adult Filarial Worms

    Science.gov (United States)

    Fox, Ellen Mueller; Morris, Christopher P.; Hübner, Marc P.; Mitre, Edward

    2015-01-01

    Filariae are tissue-invasive nematodes that cause diseases such as elephantiasis and river blindness. The goal of this study was to characterize the role of histamine during Litomosoides sigmodontis infection of BALB/c mice, a murine model of filariasis. Time course studies demonstrated that while expression of histidine decarboxylase mRNA increases throughout 12 weeks of infection, serum levels of histamine exhibit two peaks—one 30 minutes after primary infection and one 8 weeks later. Interestingly, mice treated with fexofenadine, a histamine receptor 1 inhibitor, demonstrated significantly reduced worm burden in infected mice compared to untreated infected controls. Although fexofenadine-treated mice had decreased antigen-specific IgE levels as well as lower splenocyte IL-5 and IFNγ production, they exhibited a greater than fourfold rise in eosinophil numbers at the tissue site where adult L. sigmodontis worms reside. Fexofenadine-mediated clearance of L. sigmodontis worms was dependent on host eosinophils, as fexofenadine did not decrease worm burdens in eosinophil-deficient dblGATA mice. These findings suggest that histamine release induced by tissue invasive helminths may aid parasite survival by diminishing eosinophilic responses. Further, these results raise the possibility that combining H1 receptor inhibitors with current anthelmintics may improve treatment efficacy for filariae and other tissue-invasive helminths. PMID:26204515

  18. Typical and Atypical Antipsychotic Drugs Increase Extracellular Histamine Levels in the Rat Medial Prefrontal Cortex: Contribution of Histamine H1 Receptor Blockade

    Directory of Open Access Journals (Sweden)

    Kjell A Svensson

    2012-05-01

    Full Text Available Atypical antipsychotics such as clozapine and olanzapine have been shown to enhance histamine turnover and this effect has been hypothesized to contribute to their improved therapeutic profile compared to typical antipsychotics. In the present study, we examined the effects of antipsychotic drugs on histamine (HA efflux in the mPFC of the rat by means of in vivo microdialysis and sought to differentiate the receptor mechanisms which underlie such effects. Olanzapine and clozapine increased mPFC HA efflux in a dose related manner. Increased HA efflux was also observed after quetiapine, chlorpromazine and perphenazine treatment. We found no effect of the selective 5-HT2A antagonist MDL100907, 5-HT2c antagonist SB242084 or the 5-HT6 antagonist Ro 04-6790 on mPFC HA efflux. HA efflux was increased following treatment with selective H1 receptor antagonists pyrilamine, diphenhydramine and triprolidine, the H3 receptor antagonist ciproxifan and the mixed 5HT2A/H1 receptor antagonist ketanserin. The potential novel antipsychotic drug FMPD, which has a lower affinity at H1 receptors than olanzapine, did not affect HA efflux. Similarly, other antipsychotics with lower H1 receptor affinity (risperidone, aripiprazole and haloperidol were also without effect on HA efflux. Perfusion of clozapine and pyrilamine into the TMN, but not the mPFC, increased local HA efflux. Finally, HA efflux after antipsychotic treatment was significantly correlated with affinity at H1 receptors whereas 9 other receptors, including 5-HT2A, were not. These results demonstrate that both typical and atypical antipsychotics increase mPFC histamine efflux and this effect may be mediated via antagonism of histamine H1 receptors.

  19. Role of protein kinase A in the inhibition of human mast cell histamine release by β-adrenergic receptor agonists

    Directory of Open Access Journals (Sweden)

    Toshinobu Kato

    2002-01-01

    Conclusions: The present results suggest that PKA activation induced by β-adrenergic receptor agonists plays a crucial role in inhibiting IgE-mediated histamine release from human cultured mast cells through suppressing PKC translocation.

  20. Histamine H₃ receptors, the complex interaction with dopamine and its implications for addiction.

    Science.gov (United States)

    Ellenbroek, B A

    2013-09-01

    Histamine H₃ receptors are best known as presynaptic receptors inhibiting the release of histamine, as well as other neurotransmitters including acetylcholine and dopamine. However, in the dorsal and ventral striatum, the vast majority of H₃ receptors are actually located postsynaptically on medium sized spiny output neurons. These cells also contain large numbers of dopamine (D₁ and D₂) receptors and it has been shown that H₃ receptors form heterodimers with both D₁ and D₂ receptors. Thus, the anatomical localization of H₃ receptors suggests a complex interaction that could both enhance and inhibit dopaminergic neurotransmission. Dopamine, especially within the striatal complex, plays a crucial role in the development of addiction, both in the initial reinforcing effects of drugs of abuse, as well as in maintenance, relapse and reinstatement of drug taking behaviour. It is, therefore, conceivable that H₃ receptors can moderate the development and maintenance of drug addiction. In the present review, we appraise the current literature on the involvement of H₃ receptors in drug addiction and try to explain these data within a theoretical framework, as well as provide suggestions for further research. © 2013 The British Pharmacological Society.

  1. Histamine induces NF-κB controlled cytokine secretion by orbital fibroblasts via histamine receptor type-1

    NARCIS (Netherlands)

    S. Virakul (Sita); T. Phetsuksiri (Tanachaporn); C. van Holten-Neelen; B. Schrijver (Benjamin); L. van Steensel (Leendert); V.A.S.H. Dalm (Virgil); A.D.A. Paridaens (Dion); W.A. van den Bosch (Willem); P.M. van Hagen (Martin); W.A. Dik (Willem)

    2016-01-01

    textabstractMast cells and their products are likely to be involved in regulating orbital fibroblast activity in Graves' Ophthalmopathy (GO). Histamine is abundantly present in granules of mast cells and is released upon mast cell activation. However, the effect of histamine on orbital fibroblasts

  2. Histamine induces KCNQ channel-dependent gamma oscillations in rat hippocampus via activation of the H1 receptor.

    Science.gov (United States)

    Andersson, Richard; Galter, Dagmar; Papadia, Daniela; Fisahn, André

    2017-05-15

    Histamine is an aminergic neurotransmitter, which regulates wakefulness, arousal and attention in the central nervous system. Histamine receptors have been the target of efforts to develop pro-cognitive drugs to treat disorders such as Alzheimer's disease and schizophrenia. Cognitive functions including attention are closely associated with gamma oscillations, a rhythmical electrical activity pattern in the 30-80 Hz range, which depends on the synchronized activity of excitatory pyramidal cells and inhibitory fast-spiking interneurons. We set out to explore whether histamine has a role in promoting gamma oscillations in the hippocampus. Using in-situ hybridization we demonstrate that histamine receptor subtypes 1, 2 and 3 are expressed in stratum pyramidale of area CA3 in rats. We show that both pyramidal cells and fast-spiking interneurons depolarize and increase action potential firing in response to histamine in vitro. The activation of histamine receptors generates dose-dependent, transient gamma oscillations in area CA3 of the hippocampus - the locus of the gamma rhythm generator. We also demonstrate that this histamine effect is independent of muscarinic receptors. Using specific antagonists we provide evidence that histamine gamma rhythmogenesis specifically depends on the H1 receptor. Histamine also depolarized both pyramidal cells and fast-spiking interneurons and increased membrane resistance in pyramidal cells. The increased membrane resistance is potentially mediated by the inhibition of potassium channels because application of the KCNQ channel opener ICA110381 abolished the oscillations. Taken together our data demonstrate a novel and physiological mechanism for generating gamma oscillations in hippocampus and suggest a role for KCNQ channels in this cognition-relevant brain activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Histamine 1 receptor-Gβγ-cAMP/PKA-CFTR pathway mediates the histamine-induced resetting of the suprachiasmatic circadian clock.

    Science.gov (United States)

    Kim, Yoon Sik; Kim, Young-Beom; Kim, Woong Bin; Lee, Seung Won; Oh, Seog Bae; Han, Hee-Chul; Lee, C Justin; Colwell, Christopher S; Kim, Yang In

    2016-05-06

    Recent evidence indicates that histamine, acting on histamine 1 receptor (H1R), resets the circadian clock in the mouse suprachiasmatic nucleus (SCN) by increasing intracellular Ca(2+) concentration ([Ca(2+)]i) through the activation of CaV1.3 L-type Ca(2+) channels and Ca(2+)-induced Ca(2+) release from ryanodine receptor-mediated internal stores. In the current study, we explored the underlying mechanisms with various techniques including Ca(2+)- and Cl(-)-imaging and extracellular single-unit recording. Our hypothesis was that histamine causes Cl(-) efflux through cystic fibrosis transmembrane conductance regulator (CFTR) to elicit membrane depolarization needed for the activation of CaV1.3 Ca(2+) channels in SCN neurons. We found that histamine elicited Cl(-) efflux and increased [Ca(2+)]i in dissociated mouse SCN cells. Both of these events were suppressed by bumetanide [Na(+)-K(+)-2Cl(-) cotransporter isotype 1 (NKCC1) blocker], CFTRinh-172 (CFTR inhibitor), gallein (Gβγ protein inhibitor) and H89 [protein kinase A (PKA) inhibitor]. By itself, H1R activation with 2-pyridylethylamine increased the level of cAMP in the SCN and this regulation was prevented by gallein. Finally, histamine-evoked phase shifts of the circadian neural activity rhythm in the mouse SCN slice were blocked by bumetanide, CFTRinh-172, gallein or H89 and were not observed in NKCC1 or CFTR KO mice. Taken together, these results indicate that histamine recruits the H1R-Gβγ-cAMP/PKA pathway in the SCN neurons to activate CaV1.3 channels through CFTR-mediated Cl(-) efflux and ultimately to phase-shift the circadian clock. This pathway and NKCC1 may well be potential targets for agents designed to treat problems resulting from the disturbance of the circadian system.

  4. Sensory responses of human skin to synthetic histamine analogues and histamine.

    OpenAIRE

    Davies, M.G.; Greaves, M W

    1980-01-01

    The potential for itch production in human skin of the synthetic analogues of histamine, 2-methyl histamine (an H1-receptor agonist) and 4-methyl histamine and dimaprit (H2-receptor agonists) has been studied in vivo and compared with histamine. Itch thresholds for 2-methyl histamine were consistently much higher than for histamine (P < 0.001). The H1-receptor antagonist chlorpheniramine raised the itch thresholds to 2-methyl histamine and histamine significantly (P < 0.001). Pruritus was not...

  5. 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...

  6. Preclinical pharmacology of bilastine, a new selective histamine H1 receptor antagonist: receptor selectivity and in vitro antihistaminic activity.

    Science.gov (United States)

    Corcóstegui, Reyes; Labeaga, Luis; Innerárity, Ana; Berisa, Agustin; Orjales, Aurelio

    2005-01-01

    This study aimed to establish the receptor selectivity and antihistaminic activity of bilastine, a new selective antihistamine receptor antagonist. In vitro experiments were conducted using a receptor binding screening panel and guinea-pig and rat tissues. Antihistaminic activity was determined using H1 receptor binding studies and in vitro H1 antagonism studies conducted in guinea-pig tissues and human cell lines. Receptor selectivity was established using a receptor binding screening panel and a receptor antagonism screening conducted in guinea-pig, rat and rabbit tissues. Inhibition of inflammatory mediators was determined through the Schultz-Dale reaction in sensitised guinea-pig ileum. Bilastine binds to histamine H1-receptors as indicated by its displacement of [3H]-pyrilamine from H1-receptors expressed in guinea-pig cerebellum and human embryonic kidney (HEK) cell lines. The studies conducted on guinea-pig smooth muscle demonstrated the capability of bilastine to antagonise H1-receptors. Bilastine is selective for histamine H1-receptors as shown in receptor-binding screening conducted to determine the binding capacity of bilastine to 30 different receptors. The specificity of its H1-receptor antagonistic activity was also demonstrated in a series of in vitro experiments conducted on guinea-pig and rat tissues. The results of these studies confirmed the lack of significant antagonism against serotonin, bradykinin, leukotriene D4, calcium, muscarinic M3-receptors, alpha1-adrenoceptors, beta2-adrenoceptors, and H2- and H3-receptors. The results of the in vitro Schultz-Dale reaction demonstrated that bilastine also has anti-inflammatory activity. These preclinical studies provide evidence that bilastine has H1- antihistamine activity, with high specificity for H1-receptors, and poor or no affinity for other receptors. Bilastine has also been shown to have anti-inflammatory properties.

  7. Rupatadine effectively prevents the histamine-induced up regulation of histamine H1R and bradykinin B2R receptor gene expression in the rat paw.

    Science.gov (United States)

    Molyva, Dimitra; Kalokasidis, Konstantinos; Poulios, Christos; Dedi, Hara; Karkavelas, George; Mirtsou, Vassiliki; Goulas, Antonis

    2014-12-01

    Activation of histamine H1 receptor (H1R) is a well-known hallmark of allergic and inflammatory pathology. Both types of bradykinin receptors (B1R and B2R) are also known to contribute significantly to the latter and some sort of functional interaction between them and H1R has been alluded to in the past. Here we use an experimental model of rat paw oedema formation to examine the effect of exogenously added histamine on the gene expression of H1R and bradykinin receptors B1R and B2R, alone or in combination to rupatadine, a second generation antihistamine agent. Histamine-induced oedema formation was monitored with a plethysmometer. The gene expression of H1R, B1R and B2R was analyzed with both conventional and real-time PCR. Rupatadine fumarate was used in pure form and administered intraperitoneally, prior to histamine injection into the paw. Microscopy of haematoxylin and eosin-stained sections of paw tissue was used to examine effects on tissue architecture. Histamine injection into the paw resulted in significant up regulation of H1R and B2R without inducing significant cellular infiltration, but appears to affect less the expression of B1R. Rupatadine was, under the conditions used in this study, very effective in preventing this effect and in suppressing oedema formation through its antihistamine action. Rupatadine has a suppressing effect on H1R and B2R gene expression which could add to its efficacy towards allergy and allergy-like conditions. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  8. Diether derivatives of homo- or substituted piperidines as non-imidazole histamine H3 receptor ligands.

    Science.gov (United States)

    Łazewska, Dorota; Kuder, Kamil; Ligneau, Xavier; Camelin, Jean-Claude; Schunack, Walter; Stark, Holger; Kieć-Kononowicz, Katarzyna

    2009-04-15

    Synthesis and biological activities of a series of homo- or substituted piperidine unsymmetrical diethers are described. The novel compounds were evaluated for histamine H(3) receptor binding affinities at recombinant human H(3) receptor stably expressed in HEK-293 cells. All diethers showed in vitro affinities in nanomolar concentration range. The most potent compounds are 1-[3-(3-(4-chlorophenoxy)propoxy)propyl]-3-methylpiperidine 11 (K(i)=3.2 nM) and 1-[3-(3-(4-chlorophenoxy)propoxy)propyl]azepane 13 (K(i)=3.5 nM).

  9. Piperidine variations in search for non-imidazole histamine H(3) receptor ligands.

    Science.gov (United States)

    Łazewska, Dorota; Kuder, Kamil; Ligneau, Xavier; Schwartz, Jean-Charles; Schunack, Walter; Stark, Holger; Kieć-Kononowicz, Katarzyna

    2008-09-15

    Synthesis and biological evaluation of the novel histamine H(3) receptor ligands is described. Two series of ethers (aliphatic and aromatic) have been prepared by four different methods. Compounds were evaluated for their affinities at recombinant human H(3) receptor stably expressed in CHO cells. The ethers show from low to moderate in vitro affinities in nanomolar concentration range. The most potent compound was the 1-[3-(4-tert-butylphenoxy)propyl]-4-piperidino-piperidine 16 (hH(3)R K(i)=100 nM). Several members of the new series investigated under in vivo conditions, proved to be inactive.

  10. Inverse agonistic activity of antihistamines and suppression of histamine H1 receptor gene expression.

    Science.gov (United States)

    Mizuguchi, Hiroyuki; Ono, Shohei; Hattori, Masashi; Fukui, Hiroyuki

    2012-01-01

    Histamine H(1) receptor (H1R) expression influences the severity of allergy symptoms. We examined the effect of inverse agonists on H1R gene expression. Two inverse agonists (carebastine and mepyramine), but not the neutral antagonist oxatomide, decreased inositol phosphate accumulation. The inverse agonists also decreased H1R gene expression and down-regulated H1R mRNA below basal expression, while basal H1R mRNA expression was maintained after oxatomide treatment. These results suggest that inverse agonists more potently alleviate allergy symptoms by not only inhibiting stimulus-induced up-regulation of H1R gene expression but also by suppressing basal histamine signaling through their inverse agonistic activity.

  11. Sensitization of the histamine H1 receptor by increased ligand affinity.

    NARCIS (Netherlands)

    Bloemers, S.M.; Verheule, S.; Peppelenbosch, M.P.; Smit, M.J.; Tertoolen, L.G.J.; de Laat, S.

    1998-01-01

    Histamine regulates a variety of physiological processes including inflammation, gastric acid secretion, and neurotransmission. The cellular response to histamine is subject to dynamic control, and exaggerated histamine reactivity in response to cysteinyl leukotrienes and other stimuli is important

  12. Histamine receptors expressed in circulating progenitor cells have reciprocal actions in ligation-induced arteriosclerosis.

    Science.gov (United States)

    Yamada, Sohsuke; Wang, Ke-Yong; Tanimoto, Akihide; Guo, Xin; Nabeshima, Atsunori; Watanabe, Takeshi; Sasaguri, Yasuyuki

    2013-09-01

    Histamine is synthesized as a low-molecular-weight amine from L-histidine by histidine decarboxylase (HDC). Recently, we demonstrated that carotid artery-ligated HDC gene-deficient mice (HDC(-/-)) showed less neointimal formation than wild-type (WT) mice, indicating that histamine participates in the process of arteriosclerosis. However, little is known about the roles of histamine-specific receptors (HHRs) in arteriosclerosis. To define the roles of HHRs in arteriosclerosis, we investigated intimal remodeling in ligated carotid arteries of HHR-deficient mice (H1R(-/-) or H2R(-/-)). Quantitative analysis showed that H1R(-/-) mice had significantly less arteriosclerogenesis, whereas H2R(-/-) mice had more, as compared with WT mice. Bone marrow transplantation from H1R(-/-) or H2R(-/-) to WT mice confirmed the above observation. Furthermore, the increased expression of monocyte chemoattractant protein (MCP-1), platelet-derived growth factor (PDGF), adhesion molecules and liver X receptor (LXR)-related inflammatory signaling factors, including Toll-like receptor (TLR3), interleukin-1 receptor (IL-1R) and tumor necrosis factor receptor (TNF-R), was consistent with the arteriosclerotic phenotype of H2R(-/-) mice. Peripheral progenitor cells in H2R(-/-) mice accelerate ligation-induced arteriosclerosis through their regulation of MCP-1, PDGF, adhesion molecules and LXR-related inflammatory signaling factors. In contrast, peripheral progenitor cells act to suppress arteriosclerosis in H1R(-/-) mice, indicating that HHRs reciprocally regulate inflammation in the ligation-induced arteriosclerosis. © 2013 The Authors. Pathology International © 2013 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.

  13. Estrogenic regulation of histamine receptor subtype H1 expression in the ventromedial nucleus of the hypothalamus in female rats.

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    Hiroko Mori

    Full Text Available Female sexual behavior is controlled by central estrogenic action in the ventromedial nucleus of the hypothalamus (VMN. This region plays a pivotal role in facilitating sex-related behavior in response to estrogen stimulation via neural activation by several neurotransmitters, including histamine, which participates in this mechanism through its strong neural potentiating action. However, the mechanism through which estrogen signaling is linked to the histamine system in the VMN is unclear. This study was undertaken to investigate the relationship between estrogen and histamine receptor subtype H1 (H1R, which is a potent subtype among histamine receptors in the brain. We show localization of H1R exclusively in the ventrolateral subregion of the female VMN (vl VMN, and not in the dorsomedial subregion. In the vl VMN, abundantly expressed H1R were mostly colocalized with estrogen receptor α. Intriguingly, H1R mRNA levels in the vl VMN were significantly elevated in ovariectomized female rats treated with estrogen benzoate. These data suggest that estrogen can amplify histamine signaling by enhancing H1R expression in the vl VMN. This enhancement of histamine signaling might be functionally important for allowing neural excitation in response to estrogen stimulation of the neural circuit and may serve as an accelerator of female sexual arousal.

  14. Temporal responses of cutaneous blood flow and plasma catecholamine concentrations to histamine H1- or H2-receptor stimulation in man

    DEFF Research Database (Denmark)

    Knigge, U; Alsbjørn, B; Thuesen, B

    1988-01-01

    We have studied the effect of histamine and H1- or H2-receptor antagonists on cutaneous blood flow and catecholamine release in man. Histamine was infused alone or in combination with mepyramine, an H1-antagonist or cimetidine, an H2-antagonist for 2 h. Cutaneous blood flow was measured continuou......We have studied the effect of histamine and H1- or H2-receptor antagonists on cutaneous blood flow and catecholamine release in man. Histamine was infused alone or in combination with mepyramine, an H1-antagonist or cimetidine, an H2-antagonist for 2 h. Cutaneous blood flow was measured...... that histamine causes an immediate cutaneous vasodilatation through H1-receptors and a more sustained response through H2-receptors. The vasodilatation is accompanied by an increase in plasma catecholamine concentrations. Despite the continuous infusion of histamine, blood flow decreased during the last hour...

  15. Large-scale overproduction, functional purification and ligand affinities of the His-tagged human histamine H1 receptor.

    NARCIS (Netherlands)

    Ratnala, V.R.; Swarts, H.G.P.; Oostrum, J. van; Leurs, R.; Groot, H.J.M. de; Bakker, R.; Grip, W.J. de

    2004-01-01

    This report describes an efficient strategy for amplified functional purification of the human H1 receptor after heterologous expression in Sf9 cells. The cDNA encoding a C-terminally histidine-tagged (10xHis) human histamine H1 receptor was used to generate recombinant baculovirus in a Spodoptera

  16. Effects of a thromboxane receptor antagonist on prostaglandin D2 and histamine induced bronchoconstriction in man.

    Science.gov (United States)

    al Jarad, N; Hui, K P; Barnes, N

    1994-01-01

    Many prostanoids including are prostaglandin (PG) F2 alpha and PGD2 are potent bronchoconstrictor agents. There is evidence to suggest that airway thromboxane (TP) receptor may act as a common receptor for their bronchoconstrictor actions. We tested the hypothesis that inhaled prostaglandin (PG) D2-induced bronchoconstriction is mediated by interacting with the TP receptor antagonist, ICI 192605, on the bronchoconstrictor response to inhaled PGD2 in a double-blind, placebo-controlled and crossed-over trial in normal subjects. The effect of ICI 192605 on histamine induced bronchoconstriction served as control for non-specific bronchodilatory actions. The study had two phases; the first consisted of two inhaled PGD2 challenge study days, and the second phase was that of inhaled histamine. Each study day was separated by at least a week. On each study day, the challenge tests were carried out 30 min after ingestion of 100 mg ICI 192605 or placebo. Doubling concentrations of agonist were given till more than 35% fall in post-diluent specific airway conductance (sGaw) occurred. The concentration needed to cause a fall in a sGaw of 35% post-diluent value (PC35sGaw) was then determined from linear interpolation of the log dose-response. Eight male subjects (median age 26, range 20-35 years) completed the study. ICI 192605 did not change baseline airway calibre 30 min after ingestion on either PGD2 or histamine study days. ICI 192605 significantly shifted the dose-response curve to inhaled PGD2 to the right by a median of 3.4 fold (Wilcoxon rank sign test, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Histamine-2 receptor antagonist famotidine modulates cardiac stem cell characteristics in hypertensive heart disease

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    Sherin Saheera

    2017-10-01

    Full Text Available Background Cardiac stem cells (CSCs play a vital role in cardiac homeostasis. A decrease in the efficiency of cardiac stem cells is speculated in various cardiac abnormalities. The maintenance of a healthy stem cell population is essential for the prevention of adverse cardiac remodeling leading to cardiac failure. Famotidine, a histamine-2 receptor antagonist, is currently used to treat ulcers of the stomach and intestines. In repurposing the use of the drug, reduction of cardiac hypertrophy and improvement in cardiac function of spontaneously hypertensive rats (SHR was reported by our group. Given that stem cells are affected in cardiac pathologies, the effect of histamine-2 receptor antagonism on CSC characteristics was investigated. Methods To examine whether famotidine has a positive effect on CSCs, spontaneously hypertensive rats (SHR treated with the drug were sacrificed; and CSCs isolated from atrial appendages was evaluated. Six-month-old male SHRs were treated with famotidine (30 mg/kg/day for two months. The effect of famotidine treatment on migration, proliferation and survival of CSCs was compared with untreated SHRs and normotensive Wistar rats. Results Functional efficiency of CSCs from SHR was compromised relative to that in Wistar rat. Famotidine increased the migration and proliferation potential, along with retention of stemness of CSCs in treated SHRs. Cellular senescence and oxidative stress were also reduced. The expression of H2R was unaffected by the treatment. Discussion As anticipated, CSCs from SHRs were functionally impaired. Stem cell attributes of famotidine-treated SHRs was comparable to that of Wistar rats. Therefore, in addition to being cardioprotective, the histamine 2 receptor antagonist modulated cardiac stem cells characteristics. Restoration of stem cell efficiency by famotidine is possibly mediated by reduction of oxidative stress as the expression of H2R was unaffected by the treatment. Maintenance of

  18. Structure-Based Prediction of Subtype Selectivity of Histamine H3 Receptor Selective Antagonists in Clinical Trials

    DEFF Research Database (Denmark)

    Kim, Soo-Kyung; Fristrup, Peter; Abrol, Ravinder

    2011-01-01

    applications, including treatment of Alzheimer’s disease, attention deficit hyperactivity disorder (ADHD), epilepsy, and obesity.(1) However, many of these drug candidates cause undesired side effects through the cross-reactivity with other histamine receptor subtypes. In order to develop improved selectivity......Histamine receptors (HRs) are excellent drug targets for the treatment of diseases, such as schizophrenia, psychosis, depression, migraine, allergies, asthma, ulcers, and hypertension. Among them, the human H3 histamine receptor (hH3HR) antagonists have been proposed for specific therapeutic...... and activity for such treatments, it would be useful to have the three-dimensional structures for all four HRs. We report here the predicted structures of four HR subtypes (H1, H2, H3, and H4) using the GEnSeMBLE (GPCR ensemble of structures in membrane bilayer environment) Monte Carlo protocol,(2) sampling...

  19. Short-term desensitization of the histamine H1 receptor in human HeLa cells : involvement of protein kinase C dependent and independent pathways

    NARCIS (Netherlands)

    Smit, M J; Bloemers, S M; Leurs, R; Tertoolen, L G; Bast, A; de Laat, S W; Timmerman, H

    1992-01-01

    1. In this study we have investigated the effects of short-term exposure of cells to histamine on the subsequent H1 receptor responsiveness in HeLa cells, using Ca2+ fluorescence microscopy and video digital imaging. 2. In HeLa cells, histamine (100 microM) induces an immediate H1 receptor-mediated

  20. Histamine Release from Mast Cells and Basophils.

    Science.gov (United States)

    Borriello, Francesco; Iannone, Raffaella; Marone, Gianni

    2017-01-01

    Mast cells and basophils represent the most relevant source of histamine in the immune system. Histamine is stored in cytoplasmic granules along with other amines (e.g., serotonin), proteases, proteoglycans, cytokines/chemokines, and angiogenic factors and rapidly released upon triggering with a variety of stimuli. Moreover, mast cell and basophil histamine release is regulated by several activating and inhibitory receptors. The engagement of different receptors can trigger different modalities of histamine release and degranulation. Histamine released from mast cells and basophils exerts its biological activities by activating four G protein-coupled receptors, namely H1R, H2R, H3R (expressed mainly in the brain), and the recently identified H4R. While H1R and H2R activation accounts mainly for some mast cell- and basophil-mediated allergic disorders, the selective expression of H4R on immune cells is uncovering new roles for histamine (possibly derived from mast cells and basophils) in allergic, inflammatory, and autoimmune disorders. Thus, the in-depth knowledge of mast cell and basophil histamine release and its biologic effects is poised to uncover new therapeutic avenues for a wide spectrum of disorders.

  1. Discovery of novel lead in the group of N-substituted piperazine ether derivatives with potential histamine H3 receptor activity.

    Science.gov (United States)

    Kuder, Kamil J; Stachnik, Marta; Schunack, Walter; Szymańska, Ewa; Kieć-Kononowicz, Katarzyna

    2014-01-01

    The search for novel lead from the group of various substituted N-piperazine ether derivatives was performed. Acyl- and pyridylpiperazine ethyl/propyl ethers were obtained via three different synthetic pathways. Affinity to histamine H3 receptor was established, as well as, for selected compounds, selectivity towards histamine H4R. Docking studies to the histamine H3R homology model strengthened the position of (4-(3-(4-(3-chlorobenzoyl)piperazin-1- yl)propoxy)phenyl)(cyclopropyl)methanone (compound 26) as a novel lead for further studies on histamine H3 receptor antagonist/inverse agonist.

  2. Proxyfan acts as a neutral antagonist of histamine H3 receptors in the feeding-related hypothalamic ventromedial nucleus.

    Science.gov (United States)

    Clapp, R H; Luckman, S M

    2012-11-01

    Centrally acting histamine H(3) receptor ligands are proposed as potential treatments for obesity, although the value of inverse agonists at these receptors is still debated. Functional inhibition of H(3) autoreceptors activates neurones in a hypothalamic 'satiety' centre. The H(3) receptor antagonist, proxyfan was used as a tool to assess the action of histaminergic compounds in this model. We compared the actions of histamine on feeding with those of an H(3) receptor agonist (imetit) and inverse agonist (thioperamide) in rats and mice. Sites of action were identified by immunohistochemistry and the hypothalamic ventromedial nucleus (VMN) was investigated using electrophysiological techniques. Central histamine or thioperamide decreased fast-induced feeding, whereas imetit increased feeding. Systemic thioperamide entered the brain to activate hypothalamic feeding centres and to reduce feeding without causing any adverse behaviours. Thioperamide activated neurones in the VMN through an action on histamine autoreceptors, whilst imetit had the opposite effect. Proxyfan administered alone did not affect either feeding or electrical activity. However, it blocked the actions of both thioperamide and imetit, acting as a neutral antagonist in this system. The H(3) receptor inverse agonist, thioperamide, potently reduced appetite without adverse behavioural effects. This action was blocked by proxyfan, acting as a neutral antagonist in this model and, therefore, this compound is useful in determining the selectivity of H(3) receptor-directed drugs. A major action of thioperamide is through presynaptic autoreceptors, inducing stimulation by endogenous histamine of postsynaptic H(1 ) receptors on anorectic hypothalamic neurones. © 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.

  3. In vivo pharmacological characterisation of bilastine, a potent and selective histamine H1 receptor antagonist.

    Science.gov (United States)

    Corcóstegui, Reyes; Labeaga, Luis; Innerárity, Ana; Berisa, Agustín; Orjales, Aurelio

    2006-01-01

    We set out to establish the in vivo histamine H(1) receptor antagonistic (antihistaminic) and antiallergic properties of bilastine. In vivo antihistaminic activity experiments consisted of measurement of: inhibition of increase in capillary permeability and reduction in microvascular extravasation and bronchospasm in rats and guinea pigs induced by histamine and other inflammatory mediators; and protection against lethality induced by histamine and other inflammatory mediators in rats. In vivo antiallergic activity experiments consisted of measurement of passive and active cutaneous anaphylactic reactions as well as type III and type IV allergic reactions in sensitised rodents. In the in vivo antihistaminic activity experiments, bilastine was shown to have a positive effect, similar to that of cetirizine and more potent than that of fexofenadine. The results of the in vivo antiallergic activity experiments showed that the properties of bilastine in this setting are similar to those observed for cetirizine and superior to fexofenadine in the model of passive cutaneous anaphylactic reaction. When active cutaneous anaphylactic reaction experiments were conducted, bilastine showed significant activity, less potent than that observed with cetirizine but superior to that of fexofenadine. Evaluation of the type III allergic reaction showed that of the antihistamines only bilastine was able to inhibit oedema in sensitised mice, although its effect in this respect was much less potent than that observed with dexamethasone. In terms of the type IV allergic reaction, neither bilastine, cetirizine nor fexofenadine significantly modified the effect caused by oxazolone. The results of our in vivo preclinical studies corroborate those obtained from previously conducted in vitro experiments of bilastine, and provide evidence that bilastine possesses antihistaminic as well as antiallergic properties, with similar potency to cetirizine and superior potency to fexofenadine.

  4. Anti-ulcer compound from Voacanga africana with possible histamine H2 receptor blocking activity.

    Science.gov (United States)

    Tan, P V; Nyasse, B

    2000-12-01

    Voacanga africana is used in Cameroonian ethnomedicine for the treatment of peptic ulcers. We have tested the cytoprotective, anti-secretory and ulcer healing actions of an alkaloid (TN) obtained from the fruit extract. Oral administration of TN (50-100 mg/kg) dose-dependently prevented ulcer formation by HCl/ethanol (36-75%), absolute ethanol (43-75%), HCl-ethanol/indomethacin (58-84%), Pylorus ligation (31-100%), cold restraint stress (68-100%) and histamine (49-100%). The inhibitory effect at 50 and 100 mg/kg against HCl/ethanol was not suppressed by pre-treatment with indomethacin (20 mg/kg, i.p.). TN reduced Shay-ligated gastric acid secretion from 77 mEq/l in the controls to 46 and 25 mEq/l for the 50 and 100 mg/kg doses. Augmented histamine-induced gastric acid secretion was reduced from 84 mEq/l in the controls to 45 and 21 mEq/l for the two doses of TN, with total inhibition of gastric and duodenal ulcers by the 50 mg/kg dose. Healing rate of chronic acetic acid-induced ulcers was 62 and 83%, respectively, for the dose of 50 and 100 mg/kg of TN compared with the controls. TN has gastric anti-secretory effects similar to histamine receptor blockers. Its cytoprotective and ulcer healing properties are related to its ability to strengthen gastric mucosal defenses through enhanced gastric mucus production.

  5. The effects of a novel histamine-3 receptor inverse agonist on essential tremor in comparison to stable levels of alcohol.

    NARCIS (Netherlands)

    Zoethout, R.W.; Iannone, R.; Bloem, B.R.; Palcza, J.; Murphy, G.; Chodakewitz, J.; Buntinx, A.; Gottesdiener, K.; Marsilio, S.; Rosen, L.; Dyck, K. van; Louis, E.D.; Cohen, A.F.; Schoemaker, R.C.; Tokita, S.; Sato, N.; Koblan, K.S.; Hargreaves, R.H.; Renger, J.; Gerven, J.M. van

    2012-01-01

    Essential tremor (ET) is a common movement disorder. Animal studies show that histaminergic modulation may affect the pathological processes involved in the generation of ET. Histamine-3 receptor inverse agonists (H3RIA) have demonstrated attenuating effects on ET in the harmaline rat model. In this

  6. Novel chalcone-based fluorescent human histamine H3 receptor ligands as pharmacological tools

    Directory of Open Access Journals (Sweden)

    Holger eStark

    2012-03-01

    Full Text Available Novel fluorescent chalcone-based ligands at human histamine H3 receptors (hH3R have been designed, synthesized and characterized. Compounds described are non-imidazole analogues of ciproxifan with a tetralone motif. Tetralones as chemical precursors and related fluorescent chalcones exhibit affinities at hH3R in the same concentration range like that of the reference antagonist ciproxifan (hH3R pKi value of 7.2. Fluorescence characterization of our novel ligands shows emission maxima about 570 nm for yellow fluorescent chalcones and ≥600 nm for the red fluorescent derivatives. Interferences to cellular autofluorescence could be excluded. All synthesized chalcone compounds could be taken to visualize hH3R proteins in stably transfected HEK-293 cells using confocal laser scanning fluorescence microscopy. These novel fluorescent ligands possess high potential to be used as pharmacological tools for hH3R visualization in different tissues.

  7. Histamine H3 receptor: A novel therapeutic target in alcohol dependence?

    Directory of Open Access Journals (Sweden)

    Pertti ePanula

    2012-05-01

    Full Text Available The brain histaminergic system is one of the diffuse modulatory neurotransmitter systems which regulate neuronal activity in many brain areas. Studies on both rats and mice indicate that histamine H3 receptor antagonists decrease alcohol drinking in several models, like operant alcohol administration and drinking in the dark paradigm. Alcohol-induced place preference is also affected by these drugs. Moreover, mice lacking H3R do not drink alcohol like their wild type littermates, and they do not show alcohol-induced place preference. Although the mechanisms of these behaviors are still being investigated, we propose that H3R antagonists are promising candidates for use in human alcoholics, as these drugs are already tested for treatment of other disorders like narcolepsy and sleep disorders.

  8. Effects of administration of histamine and its H1, H2, and H3 receptor antagonists into the primary somatosensory cortex on inflammatory pain in rats

    Directory of Open Access Journals (Sweden)

    Esmaeal Tamaddonfard

    2014-01-01

    These results indicate that at PSC levels, histamine through post-synaptic H1, H2, and pre-synaptic H3 receptors might be involved in pain modulation. The endogenous opioid system may be involved in histamine- and thioperamide-induced antinociception.

  9. In silico analysis of the histaprodifen induced activation pathway of the guinea-pig histamine H1-receptor

    Science.gov (United States)

    Straßer, Andrea; Wittmann, Hans-Joachim

    2010-09-01

    The binding of (partial) agonists in the binding pocket of biogenic amine receptors induces a conformational change from the inactive to the active state of the receptors. There is only little knowledge about the binding pathways of ligands into binding pocket on molecular level. So far, it was not possible with molecular dynamic simulations to observe the ligand binding and receptor activation. Furthermore, there is nearly nothing known, in which state of ligand binding, the receptor gets activated. The aim of this study was to get more detailed insight into the process of ligand binding and receptor activation. With the recently developed LigPath algorithm, we scanned the potential energy surface of the binding process of dimeric histaprodifen, a partial agonist at the histamine H1-receptor, into the guinea pig histamine H1-receptor, taking also into account the receptor activation. The calculations exhibited large conformational changes of Trp6.48 and Phe6.55 during ligand binding and receptor activation. Additionally, conformational changes were also observed for Phe6.52, Tyr6.51 and Phe6.44. Conformational changes of Trp6.48 and Phe6.52 are discussed in literature as rotamer toggle switch in context with receptor activation. Additionally, the calculations indicate that the binding of dimeric histaprodifen, accompanied by receptor activation is energetically preferred. In general, this study gives new, theoretical insights onto ligand binding and receptor activation on molecular level.

  10. Effect of acute aerobic exercise and histamine receptor blockade on arterial stiffness in African Americans and Caucasians.

    Science.gov (United States)

    Yan, Huimin; Ranadive, Sushant M; Lane-Cordova, Abbi D; Kappus, Rebecca M; Behun, Michael A; Cook, Marc D; Woods, Jeffrey A; Wilund, Kenneth R; Baynard, Tracy; Halliwill, John R; Fernhall, Bo

    2017-02-01

    African Americans (AA) exhibit exaggerated central blood pressure (BP) and arterial stiffness measured by pulse wave velocity (PWV) in response to an acute bout of maximal exercise compared with Caucasians (CA). However, whether potential racial differences exist in central BP, elastic, or muscular arterial distensibility after submaximal aerobic exercise remains unknown. Histamine receptor activation mediates sustained postexercise hyperemia in CA but the effect on arterial stiffness is unknown. This study sought to determine the effects of an acute bout of aerobic exercise on central BP and arterial stiffness and the role of histamine receptors, in AA and CA. Forty-nine (22 AA, 27 CA) young and healthy subjects completed the study. Subjects were randomly assigned to take either histamine receptor antagonist or control placebo. Central blood BP and arterial stiffness measurements were obtained at baseline, and at 30, 60, and 90 min after 45 min of moderate treadmill exercise. AA exhibited greater central diastolic BP, elevated brachial PWV, and local carotid arterial stiffness after an acute bout of submaximal exercise compared with CA, which may contribute to their higher risk of cardiovascular disease. Unexpectedly, histamine receptor blockade did not affect central BP or PWV in AA or CA after exercise, but it may play a role in mediating local carotid arterial stiffness. Furthermore, histamine may mediate postexercise carotid arterial dilation in CA but not in AA. These observations provide evidence that young and healthy AA exhibit an exaggerated hemodynamic response to exercise and attenuated vasodilator response compared with CA.NEW & NOTEWORTHY African Americans are at greater risk for developing cardiovascular disease than Caucasians. We are the first to show that young and healthy African Americans exhibit greater central blood pressure, elevated brachial stiffness, and local carotid arterial stiffness following an acute bout of submaximal exercise

  11. Possible role of histamine in pathogenesis of autoimmune diseases: implications for immunotherapy with histamine-2 receptor antagonists

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen; Hammer, J H

    1992-01-01

    The immunosuppressive chemical drugs cyclosporine A (CsA) and methotrexate (Mx) have recently been shown to be of benefit in several different diseases of autoimmune origin. Cellular immune responses may play a major role in autoimmunity as autoreactive T lymphocytes appear to recognize autoantig......The immunosuppressive chemical drugs cyclosporine A (CsA) and methotrexate (Mx) have recently been shown to be of benefit in several different diseases of autoimmune origin. Cellular immune responses may play a major role in autoimmunity as autoreactive T lymphocytes appear to recognize...... the possibility, that histamine is one of the molecules involved in pathogenesis of autoimmune diseases. T cell mediated regulation and suppression of autoreactive T cells seem to be ineffective in controlling the enhanced immune reaction in patients where the discrimination between self and non-self is changed...

  12. H3 histamine receptor antagonist pitolisant reverses some subchronic disturbances induced by olanzapine in mice.

    Science.gov (United States)

    Dudek, Magdalena; Kuder, Kamil; Kołaczkowski, Marcin; Olczyk, Adrian; Żmudzka, Elżbieta; Rak, Aleksandra; Bednarski, Marek; Pytka, Karolina; Sapa, Jacek; Kieć-Kononowicz, Katarzyna

    2016-10-01

    The use of atypical antipsychotic drugs like olanzapine is associated with side effects such as sedation and depression-like symptoms, especially during the initial period of the use. It is believed that the occurrence of these undesirable effectsis mainly the result of the histamine H1receptors blockade by olanzapine. In addition, use of olanzapine increases the level of triglycerides in the blood, which correlates with growing obesity. The aim of this study was to investigate the influence of pitolisant - H3 histamine antagonist - on subchronic olanzapine-induced depresion-like symptoms, sedation and hypertriglicerydemia. Forced swim test was conducted to determinate depressive-like effect of olanzapine and antidepressive-like activity during the co-administered pitolisant. The test was performed after the first and fifteenth day of the treatment of the mice. The spontaneous activity of the mice was measured on the fourteenth day of the treatment with a special, innovative RFID-system (Radio-frequency identification system) - TraffiCage (TSE-Systems, Germany). Triglyceride levels were determined on the sixteenth day of the experiment after 15 cycles of drug administration. Daily olanzapine treatment (4 mg/kg b.w., i.p., d.p.d) for 15 days significantly induces sedation (p < 0.05) and prolongs immobility time in forced swim tests (FST) in mice (p < 0.05); and also elevates the level of triglycerides (p < 0.05). Administration of pitolisant (10 mg/kg b.w., i.p.) subsequentto olanzapine normalizes these adverse effects. This study presents a promising alternative for counteracting some behavioral changes and metabolic disturbances which occur in the early period of treatment with antipsychotic drugs.

  13. Histamine and Skin Barrier: Are Histamine Antagonists Useful for the Prevention or Treatment of Atopic Dermatitis?

    Directory of Open Access Journals (Sweden)

    Anna De Benedetto

    2015-04-01

    Full Text Available Atopic Dermatitis (AD, the most common chronic inflammatory skin disease, is characterized by an overactive immune response to a host of environmental allergens and dry, itchy skin. Over the past decade important discoveries have demonstrated that AD develops in part from genetic and/or acquired defects in the skin barrier. Histamine is an aminergic neurotransmitter involved in physiologic and pathologic processes such as pruritus, inflammation, and vascular leak. Enhanced histamine release has been observed in the skin of patients with AD and antihistamines are often prescribed for their sedating and anti-itch properties. Recent evidence suggests that histamine also inhibits the terminal differentiation of keratinocytes and impairs the skin barrier, raising the question whether histamine might play a role in AD barrier impairment. This, coupled with the notion that histamine’s effects mediated through the recently identified histamine receptor H4R, may be important in allergic inflammation, has renewed interest in this mediator in allergic diseases. In this paper we summarize the current knowledge on histamine and histamine receptor antagonists in AD and skin barrier function.

  14. (2-Arylethenyl)-1,3,5-triazin-2-amines as a novel histamine H4 receptor ligands.

    Science.gov (United States)

    Kamińska, Katarzyna; Ziemba, Julia; Ner, Joanna; Schwed, Johannes Stephan; Łażewska, Dorota; Więcek, Małgorzata; Karcz, Tadeusz; Olejarz, Agnieszka; Latacz, Gniewomir; Kuder, Kamil; Kottke, Tim; Zygmunt, Małgorzata; Sapa, Jacek; Karolak-Wojciechowska, Janina; Stark, Holger; Kieć-Kononowicz, Katarzyna

    2015-10-20

    Within the constantly growing number of histamine H4 (H4R) receptor ligands there is a large group of azine derivatives. A series of novel compounds in the group of 4-methylpiperazine-1,3,5-triazine-2-amines were designed and obtained. Considered structures were modified at the triazine 6-position by introduction of variously substituted arylethenyl moieties. Their affinities to histamine H4 receptors were evaluated in radioligand binding assays with use of Sf9 cells, transiently expressing human H4R. Pharmacological studies results allowed to identify 4-[(E)-2-(3-chlorophenyl)ethenyl]-6-(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine (Ki = 253 nM) as the most potent compound in the present series. Copyright © 2015. Published by Elsevier Masson SAS.

  15. QSAR study on the histamine (H3 receptor antagonists using the genetic algorithm: Multi parameter linear regression

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    Adimi Maryam

    2012-01-01

    Full Text Available A quantitative structure activity relationship (QSAR model has been produced for predicting antagonist potency of biphenyl derivatives as human histamine (H3 receptors. The molecular structures of the compounds are numerically represented by various kinds of molecular descriptors. The whole data set was divided into training and test sets. Genetic algorithm based multiple linear regression is used to select most statistically effective descriptors. The final QSAR model (N =24, R2=0.916, F = 51.771, Q2 LOO = 0.872, Q2 LGO = 0.847, Q2 BOOT = 0.857 was fully validated employing leaveone- out (LOO cross-validation approach, Fischer statistics (F, Yrandomisation test, and predictions based on the test data set. The test set presented an external prediction power of R2 test=0.855. In conclusion, the QSAR model generated can be used as a valuable tool for designing similar groups of new antagonists of histamine (H3 receptors.

  16. High specific activity tritiation of the pyridazin-3-one histamine H{sub 3} receptor inverse agonist CEP-27088

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Joseph R. [PerkinElmer Health Sciences, Inc. 940 Winter St. Waltham, MA 02451 (United States); Filer, Crist N., E-mail: crist.filer@perkinelmer.com [PerkinElmer Health Sciences, Inc. 940 Winter St. Waltham, MA 02451 (United States); Maniscalco, Mario [PerkinElmer Health Sciences, Inc. 940 Winter St. Waltham, MA 02451 (United States); Becknell, Nadine C.; Hudkins, Robert L. [Discovery Research, Cephalon, Inc. 145 Brandywine Parkway, West Chester, PA 19380 (United States)

    2012-03-15

    Methods are presented to tritiate and characterize radioligand (3). - Highlights: Black-Right-Pointing-Pointer This paper addresses a useful compound to study the histamine-3 receptor. Black-Right-Pointing-Pointer The compound is a member of the pyridazin-3-one heterocycle class. Black-Right-Pointing-Pointer In particular, the paper describes the installation of tritium in the compound of interest. Black-Right-Pointing-Pointer Furthermore, tritium NMR has been employed to characterize the tritiated compound.

  17. Histamine inhibits the production of interleukin-12 through interaction with H2 receptors

    NARCIS (Netherlands)

    van der Pouw Kraan, T. C.; Snijders, A.; Boeije, L. C.; de Groot, E. R.; Alewijnse, A. E.; Leurs, R.; Aarden, L. A.

    1998-01-01

    IL-12 is essential for T helper 1 (Th1) development and inhibits the induction of Th2 responses. Atopic diseases, which are characterized by Th2 responses, are associated with the overproduction of histamine. Here we present evidence that histamine, at physiological concentrations, strongly inhibits

  18. Design, synthesis and histamine H1-receptor antagonistic activity of some novel 4-amino-2-(substituted)-5-(substituted) aryl-6-[(substituted aryl) amino] pyrimidines.

    Science.gov (United States)

    Chhabria, Mahesh T; Patel, Vimal T; Rajan, Kombu S; Brahmkshatriya, Pathik S

    2009-01-01

    A series of 4-amino-2-(substituted)-5-(substituted)aryl-6-[(substituted)aryl)-amino]pyrimidines was designed based on the triangular pharmacophoric requirements for histamine H1-receptor antagonists. The designed molecules were synthesized by condensation of arylacetonitriles with respective arylisothiocyanates to form corresponding acrylonitriles followed by cyclocondensation with carboxamidines to afford substituted pyrimidines. All compounds were screened for their histamine H1-receptor antagonistic activity using the model "Inhibition of the isotonic contraction induced by histamine on isolated guinea pig ileum". Target compounds were also evaluated for their sedative potential as well as their anticholinergic activities as these two are known to be the common adverse effects of histamine H1-receptor antagonists. Compounds 2h, 2i, 2j and 2k exhibited potent histamine H1-receptor antagonistic activity, which was found to be comparable with the standard drug, cetirizine (CAS 83881-51-0) and more potent than the conventional drug mepyramine (CAS 91-84-9). Some of the compounds have displayed very low sedative potential compared to diphenhydramine (CAS 58-73-1), but was found higher than cetirizine. None of them showed anticholinergic activity indicating potentialities of this series to be developed as second-generation histamine H1-receptor antagonists.

  19. Role of the thalamic submedius nucleus histamine H1 and H 2 and opioid receptors in modulation of formalin-induced orofacial pain in rats.

    Science.gov (United States)

    Erfanparast, Amir; Tamaddonfard, Esmaeal; Taati, Mina; Dabaghi, Milad

    2015-10-01

    Histamine and opioid systems are involved in supraspinal modulation of pain. In this study, we investigated the effects of separate and combined microinjections of agonists and antagonists of histamine H1 and H2 and opioid receptors into the thalamic submedius (Sm) nucleus on the formalin-induced orofacial pain. Two guide cannulas were implanted into the right and left sides of the Sm in ketamine- and xylazine-anesthetized rats. Orofacial formalin pain was induced by subcutaneous injection of a diluted formalin solution (50 μl, 1.5%) into the vibrissa pad. Face rubbing durations were recorded at 3-min blocks for 45 min. Formalin produced a biphasic pain response (first phase: 0-3 min and second phase: 15-33 min). Separate and combined microinjections of histamine H1 and H2 receptor agonists, 2-pyridylethylamine (2-PEA) and dimaprit, respectively, and opioid receptor agonist, morphine, attenuated the second phase of pain. The analgesic effects induced by 2-PEA, dimaprit, and morphine were blocked by prior microinjections of fexofenadine (a histamine H1 receptor antagonist), famotidine (a histamine H2 receptor antagonist), and naloxone (an opioid receptor antagonist), respectively. Naloxone also prevented 2-PEA- and dimaprit-induced antinociception, and the analgesic effect induced by morphine was inhibited by fexofenadine and famotidine. These results showed the involvement of histamine H1 and H2 and opioid receptors in the Sm modulation of orofacial pain. Opioid receptor might be involved in analgesia induced by activation of histamine H1 and H2 receptors and vice versa.

  20. Does smoking interfere with the effect of histamine H2-receptor antagonists on intragastric acidity in man?

    Science.gov (United States)

    Bauerfeind, P; Cilluffo, T; Fimmel, C J; Emde, C; von Ritter, C; Kohler, W; Gugler, R; Gasser, T; Blum, A L

    1987-05-01

    The interaction between smoking and the effect of histamine H2-antagonists on intragastric acidity was examined in a double blind double dummy placebo controlled study. Healthy volunteers, 11 smokers and 10 non-smokers, were given, on four separate days at least one week apart, either placebo or cimetidine 800 mg nocte or ranitidine 2 X 150 mg per day or ranitidine 300 mg nocte. Tablets were taken at 2115 and 0900 h. Smokers smoked a cigarette hourly from 0700 to 2300 h. Breakfast, lunch, and dinner were standardised. Intragastric acidity was measured with a combined intragastric glass electrode and a solid state recorder. The subjects were fully ambulatory. The three histamine H2-receptor antagonist regimens were less effective (p = 0.04) in smokers than in non-smokers, but the difference between acidity of smokers and non-smokers was small. Means of medians of pH during a 24-h period with placebo, cimetidine 800 mg, ranitidine 2 X 150 mg and ranitidine 300 mg were 1.6, 2.3, 3.1, and 2.7 in smokers and 1.5, 2.7, 3.2, and 3.1 in non-smokers, respectively. In a second part of the study seven chronic smokers were reexamined after acutely stopping smoking: inhibition of gastric acidity by histamine H2-receptor antagonists was similar before and after withdrawal. Smoking does not affect intragastric acidity in untreated volunteers and only slightly decreases the effectiveness of histamine H2-receptor antagonists on intragastric acidity. This effect best in part explains the unfavourable effect of smoking on healing of peptic ulcer in patients treated with these drugs.

  1. Histamine-2 receptor blockers alter the fecal microbiota in premature infants.

    Science.gov (United States)

    Gupta, Raegan W; Tran, Lynn; Norori, Johana; Ferris, Michael J; Eren, A Murat; Taylor, Christopher M; Dowd, Scot E; Penn, Duna

    2013-04-01

    Bacterial colonization is considered a major risk factor for necrotizing enterocolitis (NEC). The objective of the present study was to test the hypothesis that histamine-2 receptor (H2-) blockers alter colonic bacterial colonization by analyzing and comparing the fecal microbiota in premature infants with and without H2-blocker therapy using sensitive molecular biological techniques. Seventy-six premature infants ≤1500 g or Stool samples were collected from 25 infants receiving H2-blockers and 51 babies who had never received them. Following DNA extraction and PCR amplification of 16S rRNA, 454 pyrosequencing was undertaken and the resulting sequences were subjected to comparison with published sequence libraries. Proteobacteria and Firmicutes were the major phyla contributing to fecal microbial communities. Microbial diversity was lower, relative abundance of Proteobacteria (primarily of the family Enterobacteriaceae) was increased, whereas that of Firmicutes was decreased in the stools of infants receiving H2-blockers compared with those who had never received them. Although not designed to look specifically at the effect of H2-blockers on the incidence of NEC, our study suggests that their use lowers fecal microbial diversity and shifts the microfloral pattern toward Proteobacteria. These alterations in fecal microbiota may predispose the vulnerable immature gut to necrotizing enterocolitis and suggest prudence in the use of H2-blockers in the premature infant.

  2. Aryl-1,3,5-triazine derivatives as histamine H4 receptor ligands.

    Science.gov (United States)

    Łażewska, Dorota; Więcek, Małgorzata; Ner, Joanna; Kamińska, Katarzyna; Kottke, Tim; Schwed, J Stephan; Zygmunt, Małgorzata; Karcz, Tadeusz; Olejarz, Agnieszka; Kuder, Kamil; Latacz, Gniewomir; Grosicki, Marek; Sapa, Jacek; Karolak-Wojciechowska, Janina; Stark, Holger; Kieć-Kononowicz, Katarzyna

    2014-08-18

    A series of novel 2-amino-4-(4-methylpiperazin-1-yl)-1,3,5-triazine derivatives with different aryl substituents in the 6-position was designed, synthesized and evaluated for histamine H4 receptor (H4R) affinity in Sf9 cells expressing human H4R co-expressed with G-protein subunits. Triazine derivative 8 with a 6-(p-chlorophenyl) substituent showed the highest affinity with hH4R Ki value of 203 nM and was classified as an antagonist in cAMP accumulation assay. This compound, identified as a new lead structure, demonstrated also anti-inflammatory properties in preliminary studies in mice (carrageenan-induced edema test) and neither possessed significant antiproliferative activity, nor modulated CYP3A4 activity up to concentration of 25 μM. In order to discuss structure-activity relationships molecular modeling and docking studies were undertaken. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  3. Histamine induces the production of matrix metalloproteinase-9 in human astrocytic cultures via H1-receptor subtype.

    Science.gov (United States)

    Patel, Aarti; Vasanthan, Vishnu; Fu, Wen; Fahlman, Richard P; MacTavish, David; Jhamandas, Jack H

    2016-05-01

    Accumulation of β-amyloid (Aβ) protein within the brain is a neuropathological hallmark of Alzheimer's disease (AD). One strategy to facilitate Aβ clearance from the brain is to promote Aβ catabolism. Matrix metalloproteinase-9 (MMP-9), a member of the family of Zn(+2)-containing endoproteases, known to be expressed and secreted by astrocytes, is capable of degrading Aβ. Histamine, a major aminergic brain neurotransmitter, stimulates the production of MMP-9 in keratinocytes through the histamine H1 receptor (H1R). In the present study, we show that histamine evokes a concentration- and calcium-dependent release of MMP-9 from human astrocytic U373 cells and primary cultures of human and rat astrocytes through the H1R subtype. Activation of H1R on astrocytes elevated intracellular levels of Ca(2+) that was accompanied by time-dependent increases in MAP kinase p44/p42 and PKC. In-cell western blots revealed dose-dependent increases in both enzymes, confirming involvement of these signal transduction pathways. We next investigated the extent of recombinant human MMP-9 (rhMMP-9) proteolytic activity on soluble oligomeric Aβ (soAβ). Mass spectrometry demonstrated time-dependent cleavage of soAβ (20 μM), but not another amyloidogenic protein amylin, upon incubation with rhMMP-9 (100 nM) at 1, 4 and 17 h. Furthermore, Western blots showed a shift in soAβ equilibrium toward lower order, less toxic monomeric species. In conclusion, both MAPK p44/p42 and PKC pathways appear to be involved in histamine-upregulated MMP-9 release via H1Rs in astrocytes. Furthermore, MMP-9 appears to cleave soAβ into less toxic monomeric species. Given the key role of histamine in MMP-9 release, this neurotransmitter may serve as a potential therapeutic target for AD.

  4. Histamine and the striatum.

    Science.gov (United States)

    Bolam, J Paul; Ellender, Tommas J

    2016-07-01

    The neuromodulator histamine is released throughout the brain during periods of wakefulness. Combined with an abundant expression of histamine receptors, this suggests potential widespread histaminergic control of neural circuit activity. However, the effect of histamine on many of these circuits is unknown. In this review we will discuss recent evidence for histaminergic modulation of the basal ganglia circuitry, and specifically its main input nucleus; the striatum. Furthermore, we will discuss recent findings of histaminergic dysfunction in several basal ganglia disorders, including in Parkinson's disease and most prominently, in Tourette's syndrome, which has led to a resurgence of interest in this neuromodulator. Combined, these recent observations not only suggest a central role for histamine in modulating basal ganglia activity and behaviour, but also as a possible target in treating basal ganglia disorders. This article is part of the Special Issue entitled 'Histamine Receptors'. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. Changes in gene expression induced by histamine, fexofenadine and osthole: Expression of histamine H1 receptor, COX-2, NF-κB, CCR1, chemokine CCL5/RANTES and interleukin-1β in PBMC allergic and non-allergic patients.

    Science.gov (United States)

    Kordulewska, Natalia Karolina; Kostyra, Elżbieta; Cieślińska, Anna; Matysiewicz, Michał; Fiedorowicz, Ewa; Sienkiewicz-Szłapka, Edyta

    2017-03-01

    Fexofenadine (FXF) is a third-generation antihistamine drug and osthole is assumed as a natural antihistamine alternative. This paper compares results of histamine, FXF and osthole impact on HRH-1, COX-2, NF-κB-p50, CCR1 mRNA expression. We also measured mRNA expression of IL-1β and CCL5/RANTES in incubated peripheral blood mononuclear cells (PBMC) to compared how histamine, FXF and osthole had influence on expression level and interacts on product secretion. The purpose was to investigate expression pattern in asthma PBMC. The cultures were treated 72h with FXF and osthole. We measured mRNA expression of histamine HRH-1, COX-2, NF-κB-p50, CCR1, IL-1β and CCL5/RANTES with Real-Time PCR (RT-PCR). The present study suggest that osthole may be a potential inhibitor of histamine H1 receptor activity. We also demonstrated that cells cultured with histamine increase COX-2 mRNA expression and osthole reduce it. Allergy remains one of the most common chronic diseases in Europe and it is rapidly approaching epidemic proportions; with current predictions estimating that the number of allergy-afflicted will equal the healthy population by 2020. It is therefore paramount to find new pharmaceuticals which successfully combat allergic disease. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. Proton Pump Inhibitor and Histamine-2 Receptor Antagonist Use and Iron Deficiency.

    Science.gov (United States)

    Lam, Jameson R; Schneider, Jennifer L; Quesenberry, Charles P; Corley, Douglas A

    2017-03-01

    Proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RAs) suppress gastric acid production, which can inhibit iron absorption. However, few data exist regarding whether these medications increase the risk of clinical iron deficiency. A community-based case-control study evaluated the association between acid-suppressing medication use and the subsequent risk of iron deficiency. It contrasted 77,046 patients with new iron deficiency diagnoses (January 1999-December 2013), with 389,314 controls. Medication exposures, outcomes, and potential confounders used electronic databases. We excluded patients with pre-existing risk factors for iron deficiency. Associations were estimated using conditional logistic regression. Among cases, 2343 (3.0%) received a prior ≥2-year supply of PPIs and 1063 (1.4%) received H2RAs (without PPI use). Among controls, 3354 (0.9%) received a prior ≥2-year supply of PPIs and 2247 (0.6%) H2RAs. Both ≥2 years of PPIs (adjusted odds ratio, 2.49; 95% confidence interval, 2.35-2.64) and ≥2 years of H2RAs (odds ratio, 1.58; 95% CI, 1.46-1.71) were associated with an increased subsequent risk for iron deficiency. Among PPI users, the associations were stronger for higher daily doses (>1.5 vs 1.5 pills per day for at least 10 years (odds ratio, 4.27; 95% CI, 2.53-7.21). No similar strong associations were found for other commonly used prescription medications. Among patients without known risk factors for iron deficiency, gastric acid inhibitor use for ≥2 years was associated with an increased subsequent risk of iron deficiency. The risk increased with increasing potency of acid inhibition and decreased after medication discontinuation. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

  7. Interactions between histamine H1 receptor and its antagonists by using cell membrane chromatography method.

    Science.gov (United States)

    Ma, Weina; Zhang, Dongdong; Li, Jing; Che, Delu; Liu, Rui; Zhang, Jie; Zhang, Yanmin

    2015-11-01

    A high histamine H1 receptor (H1 R) expression cell membrane chromatography (CMC) method was developed to investigate the affinity of ligands for H1 R. The affinity of ligands for H1 R was evaluated by frontal analysis. Competition studies and molecular docking study were utilized to study the interactions that occurred at specific binding sites on H1 R. The KD values measured by frontal analysis were (8.72 ± 0.21) × 10(-7)  M for azelastine, (9.12 ± 0.26) × 10(-7)  M for cyproheptadine, (9.90 ± 0.18) × 10(-7)  M for doxepin, (1.42 ± 0.13) × 10(-6)  M for astemizole, (2.25 ± 0.36) × 10(-6)  M for chlorpheniramine and (3.10 ± 0.27) × 10(-6)  M for diphenhydramine. The results had a positive correlation with those from radioligand binding assay. The ability of displacement order measured on the binding sites occupied by doxepin was doxepin (KD , (2.95 ± 0.21) × 10(-8)  M) > astemizole (KD , (5.03 ± 0.18) × 10(-7)  M) > chlorpheniramine (KD , (1.27 ± 0.16) × 10(-6)  M) > cyproheptadine (KD , (1.61 ± 0.27) × 10(-6)  M), whose order met with the scores by molecular docking study. The studies showed CMC could be applied to investigate drug-receptor interactions. © 2015 Royal Pharmaceutical Society.

  8. Quantitative measurement of histamine H{sub 1} receptors in human brains by PET and [{sup 11}C]doxepin

    Energy Technology Data Exchange (ETDEWEB)

    Mochizuki, Hideki; Kimura, Yuichi E-mail: ukimura@ieee.org; Ishii, Kenji; Oda, Keiichi; Sasaki, Toru; Tashiro, Manabu; Yanai, Kazuhiko; Ishiwata, Kiichi

    2004-02-01

    The aim of this study is to establish a method for quantitative measurement of histamine H{sub 1} receptor (H1R) in human brain by PET and [{sup 11}C]doxepin ([{sup 11}C]DOX). The estimated parameters with a two-compartment model were stable for the initial values for parameter estimation but those with a three-compartment model were not. This finding suggests that the H1R measured by the [{sup 11}C]DOX and PET can be evaluated with a two-compartment model.

  9. Molecular determinants for the high constitutive activity of the human histamine H4 receptor: functional studies on orthologues and mutants.

    Science.gov (United States)

    Wifling, D; Löffel, K; Nordemann, U; Strasser, A; Bernhardt, G; Dove, S; Seifert, R; Buschauer, A

    2015-02-01

    Some histamine H4 receptor ligands act as inverse agonists at the human H4 receptor (hH4 R), a receptor with exceptionally high constitutive activity, but as neutral antagonists or partial agonists at the constitutively inactive mouse H4 receptor (mH4 R) and rat H4 receptor (rH4 R). To study molecular determinants of constitutive activity, H4 receptor reciprocal mutants were constructed: single mutants: hH4 R-F169V, mH4 R-V171F, hH4 R-S179A, hH4 R-S179M; double mutants: hH4 R-F169V+S179A, hH4 R-F169V+S179M and mH4 R-V171F+M181S. Site-directed mutagenesis with pVL1392 plasmids containing hH4 or mH4 receptors were performed. Wild-type or mutant receptors were co-expressed with Gαi2 and Gβ1 γ2 in Sf9 cells. Membranes were studied in saturation and competition binding assays ([(3) H]-histamine), and in functional [(35) S]-GTPγS assays with inverse, partial and full agonists of the hH4 receptor. Constitutive activity decreased from the hH4 receptor via the hH4 R-F169V mutant to the hH4 R-F169V+S179A and hH4 R-F169V+S179M double mutants. F169 alone or in concert with S179 plays a major role in stabilizing a ligand-free active state of the hH4 receptor. Partial inverse hH4 receptor agonists like JNJ7777120 behaved as neutral antagonists or partial agonists at species orthologues with lower or no constitutive activity. Some partial and full hH4 receptor agonists showed decreased maximal effects and potencies at hH4 R-F169V and double mutants. However, the mutation of S179 in the hH4 receptor to M as in mH4 receptor or A as in rH4 receptor did not significantly reduce constitutive activity. F169 and S179 are key amino acids for the high constitutive activity of hH4 receptors and may also be of relevance for other constitutively active GPCRs. This article is part of a themed issue on Histamine Pharmacology Update published in volume 170 issue 1. To view the other articles in this issue visit http://onlinelibrary.wiley.com/doi/10.1111/bph.2013.170.issue-1/issuetoc.

  10. Effect of mutation of Phe 2436.44 of the histamine H2 receptor on cimetidine and ranitidine mechanism of action.

    Science.gov (United States)

    Granja-Galeano, Gina; Zappia, Carlos Daniel; Fabián, Lucas; Davio, Carlos; Shayo, Carina; Fernández, Natalia; Monczor, Federico

    2017-12-15

    Despite the pivotal role GPCRs play in cellular signaling, it is only in the recent years that structural biology has begun to elucidate how GPCRs function and to provide a platform for structure-based drug design. It is postulated that GPCR activation involves the movement of transmembrane helices. The finding that many residues, which have been shown to be critical for receptor activation and are highly conserved among different GPCRs, are clustered in particular positions of transmembrane helices suggests that activation of GPCRs may involve common molecular mechanisms. In particular, phenylalanine 6.44, located in the upper half of TMVI, is highly conserved among almost all GPCRs. We generated Phe 2436.44 Ala/Ser mutants of histamine H2 receptor and found that while the substitutions do not affect receptor expression or ligand signaling, are able to specifically alter cimetidine and ranitidine mechanisms of action from simply inactivating the receptor to produce a ligand-induced G-protein sequestering conformation, that interferes with the signaling of β2-adrenoceptor. Taking advantage of the cubic ternary complex model, and mathematically modeling our results, we hypothesize that this alteration in ligand mechanism of action is consequence of a change in ligand-induced conformational rearrangement of receptor and its effect on G-protein coupling. Our results show that receptor point mutations can not only alter receptor behavior, as shown for activating/inactivating mutations, but also can have more subtle effects changing ligand mechanism of action. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Effects of the histamine H₃ receptor antagonist ABT-239 on cognition and nicotine-induced memory enhancement in mice.

    Science.gov (United States)

    Kruk, Marta; Miszkiel, Joanna; McCreary, Andrew C; Przegaliński, Edmund; Filip, Małgorzata; Biała, Grażyna

    2012-01-01

    The strong correlation between central histaminergic and cholinergic pathways on cognitive processes has been reported extensively. However, the role of histamine H(3) receptor mechanisms interacting with nicotinic mechanisms has not previously been extensively investigated. The current study was conducted to determine the interactions of nicotinic and histamine H(3) receptor systems with regard to learning and memory function using a modified elevated plus-maze test in mice. In this test, the latency for mice to move from the open arm to the enclosed arm (i.e., transfer latency) was used as an index of memory. We tested whether ABT-239 (4-(2-{2-[(2R)-2-methylpyrrolidinyl]ethyl}-benzofuran-5-yl), an H(3) receptor antagonist/inverse agonist, had influence on two different stages of memory, i.e., memory acquisition and consolidation (administered prior to or immediately after the first trial, respectively) and whether ABT-239 influenced nicotine-induced memory enhancement. Our results revealed that the acute administration of nicotine (0.035 and 0.175 mg/kg), but not of ABT-239 (0.1-3 mg/kg) reduced transfer latency in the acquisition and consolidation phases. In combination studies, concomitant administration of either ABT-239 (1 and 3 mg/kg) and nicotine (0.035 mg/kg), or ABT-239 (0.1 mg/kg) and nicotine (0.0175 mg/kg) further increased nicotine-induced improvement in both memory acquisition and consolidation. The present data confirm an important role for H(3) receptors in regulating nicotine-induced mnemonic effects since inhibition of H(3) receptors augmented nicotine-induced memory enhancement in mice.

  12. Dual-acting diether derivatives of piperidine and homopiperidine with histamine H(3) receptor antagonistic and anticholinesterase activity.

    Science.gov (United States)

    Bajda, Marek; Kuder, Kamil J; Lażewska, Dorota; Kieć-Kononowicz, Katarzyna; Więckowska, Anna; Ignasik, Michalina; Guzior, Natalia; Jończyk, Jakub; Malawska, Barbara

    2012-08-01

    The study presents novel biological properties of diether derivatives of homo- or substituted piperidine ligands of the histamine H(3) receptor. The compounds were evaluated for their inhibitory potency against acetylcholinesterase (AChE) from the electric eel and butyrylcholinesterase (BuChE) from horse serum. The most interesting multifunctional compound 13 displayed high affinity for the cloned hH(3) R (K(i)  = 3.48 nM) and moderate inhibitory potency against both enzymes (IC(50) AChE = 7.91 µM and BuChE = 4.97 µM). Molecular modeling studies revealed interactions with key amino acid residues in the homology model of histamine H(3) receptor ligands, as well as the binding model for AChE and BuChE in the catalytic and peripheral active sites. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Histamine Regulates Actin Cytoskeleton in Human Toll-like Receptor 4-activated Monocyte-derived Dendritic Cells Tuning CD4+ T Lymphocyte Response.

    Science.gov (United States)

    Aldinucci, Alessandra; Bonechi, Elena; Manuelli, Cinzia; Nosi, Daniele; Masini, Emanuela; Passani, Maria Beatrice; Ballerini, Clara

    2016-07-08

    Histamine, a major mediator in allergic diseases, differentially regulates the polarizing ability of dendritic cells after Toll-like receptor (TLR) stimulation, by not completely explained mechanisms. In this study we investigated the effects of histamine on innate immune reaction during the response of human monocyte-derived DCs (mDCs) to different TLR stimuli: LPS, specific for TLR4, and Pam3Cys, specific for heterodimer molecule TLR1/TLR2. We investigated actin remodeling induced by histamine together with mDCs phenotype, cytokine production, and the stimulatory and polarizing ability of Th0. By confocal microscopy and RT-PCR expression of Rac1/CdC42 Rho GTPases, responsible for actin remodeling, we show that histamine selectively modifies actin cytoskeleton organization induced by TLR4, but not TLR2 and this correlates with increased IL4 production and decreased IFNγ by primed T cells. We also demonstrate that histamine-induced cytoskeleton organization is at least in part mediated by down-regulation of small Rho GTPase CdC42 and the protein target PAK1, but not by down-regulation of Rac1. The presence and relative expression of histamine receptors HR1-4 and TLRs were determined as well. Independently of actin remodeling, histamine down-regulates IL12p70 and CXCL10 production in mDCs after TLR2 and TLR4 stimulation. We also observed a trend of IL10 up-regulation that, despite previous reports, did not reach statistical significance. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Histamine Regulates Actin Cytoskeleton in Human Toll-like Receptor 4-activated Monocyte-derived Dendritic Cells Tuning CD4+ T Lymphocyte Response*

    Science.gov (United States)

    Bonechi, Elena; Manuelli, Cinzia

    2016-01-01

    Histamine, a major mediator in allergic diseases, differentially regulates the polarizing ability of dendritic cells after Toll-like receptor (TLR) stimulation, by not completely explained mechanisms. In this study we investigated the effects of histamine on innate immune reaction during the response of human monocyte-derived DCs (mDCs) to different TLR stimuli: LPS, specific for TLR4, and Pam3Cys, specific for heterodimer molecule TLR1/TLR2. We investigated actin remodeling induced by histamine together with mDCs phenotype, cytokine production, and the stimulatory and polarizing ability of Th0. By confocal microscopy and RT-PCR expression of Rac1/CdC42 Rho GTPases, responsible for actin remodeling, we show that histamine selectively modifies actin cytoskeleton organization induced by TLR4, but not TLR2 and this correlates with increased IL4 production and decreased IFNγ by primed T cells. We also demonstrate that histamine-induced cytoskeleton organization is at least in part mediated by down-regulation of small Rho GTPase CdC42 and the protein target PAK1, but not by down-regulation of Rac1. The presence and relative expression of histamine receptors HR1–4 and TLRs were determined as well. Independently of actin remodeling, histamine down-regulates IL12p70 and CXCL10 production in mDCs after TLR2 and TLR4 stimulation. We also observed a trend of IL10 up-regulation that, despite previous reports, did not reach statistical significance. PMID:27226579

  15. Histamine modulates microglia function

    Science.gov (United States)

    2012-01-01

    Background Histamine is commonly acknowledged as an inflammatory mediator in peripheral tissues, leaving its role in brain immune responses scarcely studied. Therefore, our aim was to uncover the cellular and molecular mechanisms elicited by this molecule and its receptors in microglia-induced inflammation by evaluating cell migration and inflammatory mediator release. Methods Firstly, we detected the expression of all known histamine receptor subtypes (H1R, H2R, H3R and H4R), using a murine microglial cell line and primary microglia cell cultures from rat cortex, by real-time PCR analysis, immunocytochemistry and Western blotting. Then, we evaluated the role of histamine in microglial cell motility by performing scratch wound assays. Results were further confirmed using murine cortex explants. Finally, interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels were evaluated by ELISA measurements to determine the role of histamine on the release of these inflammatory mediators. Results After 12 h of treatment, 100 μM histamine and 10 μg/ml histamine-loaded poly (lactic-co-glycolic acid) microparticles significantly stimulated microglia motility via H4R activation. In addition, migration involves α5β1 integrins, and p38 and Akt signaling pathways. Migration of microglial cells was also enhanced in the presence of lipopolysaccharide (LPS, 100 ng/ml), used as a positive control. Importantly, histamine inhibited LPS-stimulated migration via H4R activation. Histamine or H4R agonist also inhibited LPS-induced IL-1β release in both N9 microglia cell line and hippocampal organotypic slice cultures. Conclusions To our knowledge, we are the first to show a dual role of histamine in the modulation of microglial inflammatory responses. Altogether, our data suggest that histamine per se triggers microglia motility, whereas histamine impedes LPS-induced microglia migration and IL-1β release. This last datum assigns a new putative anti-inflammatory role for

  16. Donepezil, an acetylcholine esterase inhibitor, and ABT-239, a histamine H3 receptor antagonist/inverse agonist, require the integrity of brain histamine system to exert biochemical and procognitive effects in the mouse.

    Science.gov (United States)

    Provensi, Gustavo; Costa, Alessia; Passani, M Beatrice; Blandina, Patrizio

    2016-10-01

    Histaminergic H3 receptors (H3R) antagonists enhance cognition in preclinical models and modulate neurotransmission, in particular acetylcholine (ACh) release in the cortex and hippocampus, two brain areas involved in memory processing. The cognitive deficits seen in aging and Alzheimer's disease have been associated with brain cholinergic deficits. Donepezil is one of the acetylcholinesterase (AChE) inhibitor approved for use across the full spectrum of these cognitive disorders. We addressed the question if H3R antagonists and donepezil require an intact histamine neuronal system to exert their procognitive effects. The effect of the H3R antagonist ABT-239 and donepezil were evaluated in the object recognition test (ORT), and on the level of glycogen synthase kinase 3 beta (GSK-3β) phosphorylation in normal and histamine-depleted mice. Systemic administration of ABT-239 or donepezil ameliorated the cognitive performance in the ORT. However, these compounds were ineffective in either genetically (histidine decarboxylase knock-out, HDC-KO) or pharmacologically, by means of intracerebroventricular (i.c.v.) injections of the HDC irreversible inhibitor a-fluoromethylhistidine (a-FMHis), histamine-deficient mice. Western blot analysis revealed that ABT-239 or donepezil systemic treatments increased GSK-3β phosphorylation in cortical and hippocampal homogenates of normal, but not of histamine-depleted mice. Furthermore, administration of the PI3K inhibitor LY294002 that blocks GSK-3β phosphorylation, prevented the procognitive effects of both drugs in normal mice. Our results indicate that both donepezil and ABT-239 require the integrity of the brain histaminergic system to exert their procognitive effects and strongly suggest that impairments of PI3K/AKT/GSK-3β intracellular pathway activation is responsible for the inefficacy of both drugs in histamine-deficient animals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Allergy, Histamine and Antihistamines.

    Science.gov (United States)

    Church, Martin K

    2017-01-01

    This chapter concentrates on the role in allergic disease of histamine acting on H1-receptors. It is clear that allergy has its roots in the primary parasite rejection response in which mast cell-derived histamine creates an immediate hostile environment and eosinophils are recruited for killing. This pattern is seen in allergic rhinitis where the early events of mucus production and nasal itching are primarily histamine mediated whereas nasal blockage is secondary to eosinophil infiltration and activation. In asthma, the role of histamine is less clear. Urticaria is characterized by mast cell driven pruritic wheal and flare-type skin reactions that usually persist for less than 24 h. Although the events leading to mast cell degranulation have been unclear for many years, it is now becoming evident that urticaria has an autoimmune basis. Finally, the properties of first- and second-generation H1-antihistamines and their role in allergic is discussed.

  18. Up-regulation of airway smooth muscle histamine H1 receptor mRNA, protein and function by ß2-adrenoceptor activation

    NARCIS (Netherlands)

    Mak, J.CW; Roffel, A.F; Katsunuma, T; Elzinga, C.R S; Zaagsma, Hans; Barnes, P.J

    Histamine, released from activated mast cells, causes bronchoconstriction mediated by H-1 receptors, whereas beta(2)-agonists are widely used for the relief of bronchoconstriction. In this study, we examined the effects of the beta(2)-adrenoceptor agonist, fenoterol, on the expression of H-1

  19. A single dose of histamine-receptor antagonists before downhill running alters markers of muscle damage and delayed-onset muscle soreness.

    Science.gov (United States)

    Ely, Matthew R; Romero, Steven A; Sieck, Dylan C; Mangum, Joshua E; Luttrell, Meredith J; Halliwill, John R

    2017-03-01

    Histamine contributes to elevations in skeletal muscle blood flow following exercise, which raises the possibility that histamine is an important mediator of the inflammatory response to exercise. We examined the influence of antihistamines on postexercise blood flow, inflammation, muscle damage, and delayed-onset muscle soreness (DOMS) in a model of moderate exercise-induced muscle damage. Subjects consumed either a combination of fexofenadine and ranitidine (blockade, n = 12) or nothing (control, n = 12) before 45 min of downhill running (-10% grade). Blood flow to the leg was measured before and throughout 120 min of exercise recovery. Markers of inflammation, muscle damage, and DOMS were obtained before and at 0, 6, 12, 24, 48, and 72 h postexercise. At 60 min postexercise, blood flow was reduced ~29% with blockade compared with control (P histamine-receptor blockade reduced postexercise blood flow, had no effect on the pattern of inflammatory markers, increased serum creatine kinase concentrations, attenuated muscle strength loss, and reduced pain perception following muscle-damaging exercise.NEW & NOTEWORTHY Histamine appears to be intimately involved with skeletal muscle during and following exercise. Blocking histamine's actions during muscle-damaging exercise, via common over-the-counter antihistamines, resulted in increased serum creatine kinase, an indirect marker of muscle damage. Paradoxically, blocking histamine's actions attenuated muscle strength loss and reduced perceptions of muscle pain for 72 h following muscle-damaging exercise. These results indicate that exercise-induced histamine release may have a broad impact on protecting muscle from exercise-induced damage. Copyright © 2017 the American Physiological Society.

  20. Simplified PET measurement for evaluating histamine H{sub 1} receptors in human brains using [{sup 11}C]doxepin

    Energy Technology Data Exchange (ETDEWEB)

    Mochizuki, Hideki [Department of Pharmacology, Tohoku University School of Medicine, Sendai, 980-8575 (Japan); Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo, 173-0022 (Japan); Kimura, Yuichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo, 173-0022 (Japan)]. E-mail: ukimura@ieee.org; Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo, 173-0022 (Japan); Oda, Keiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo, 173-0022 (Japan); Sasaki, Toru [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo, 173-0022 (Japan); Tashiro, Manabu [Department of Pharmacology, Tohoku University School of Medicine, Sendai, 980-8575 (Japan); Yanai, Kazuhiko [Department of Pharmacology, Tohoku University School of Medicine, Sendai, 980-8575 (Japan); Ishiwata, Kiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo, 173-0022 (Japan)

    2004-11-01

    The aim of this study was to develop simplified positron emission tomography measurement using [{sup 11}C]doxepin ([{sup 11}C]DOX) to evaluate histamine H{sub 1} receptors (H1Rs) in human brains. We evaluated the correlation between the distribution volume (DV) of [{sup 11}C]DOX, estimated quantitatively with a two-compartment model, and the [{sup 11}C]DOX uptake obtained at various time intervals and normalized using the metabolite-corrected plasma radioactivity. We found that the static 70- to 90-min images normalized using the plasma radioactivity at 10 min postinjection reflected the DV of [{sup 11}C]DOX-H1R binding.

  1. Implication of prostaglandins and histamine h1 and h2 receptors in radiation-induced temperature responses of rats

    Energy Technology Data Exchange (ETDEWEB)

    Kandasamy, S.B.; Hunt, W.A.; Mickley, G.A .

    1988-01-01

    Exposure of rats to 1-15 Gy cobalt 60 gamma radiation induced hyperthermia, whereas 20-200 Gy induced hypothermia. Exposure either to the head or to the whole body to 10 Gy induced hyperthermia, while body-only exposure produced hypothermia. This observation indicates that radiation-induced fever is a result of a direct effect on the brain. The hyperthermia due to 10 Gy was significantly attenuated by the pre- or post-treatment with a cyclooxgenase inhibitor, indomethacin. Hyperthermia was also altered by the central administration of a mu receptor antagonist naloxone but only at low doses of radiation. These findings suggest that radiation-induced hyperthermia may be mediated through the synthesis and release of prostaglandins in the brain and to a lesser extent to the release of endogenous opioid peptides. The release of histamine acting on H(1) and H(2) receptors may be involved in radiation-induced hypothermia since both the H(1) receptor antagonist, mepyramine, and H(2) receptor antagonist, cimetidine, antagonized the hypothermia. The results of these studies suggested that the release of neurohumoral substances induced by exposure to ionizing radiation is dose dependent and has different consequences on physiological processes such as the regulation of body temperature. Furthermore, the antagonism of radiation-induced hyperthermia by indomethacin may have potential therapeutic implications in the treatment of fever resulting from accidental irradiations.

  2. Implication of prostaglandins and histamine H1 and H2 receptors in radiation-induced temperature responses of rats

    Energy Technology Data Exchange (ETDEWEB)

    Kandasamy, S.B.; Hunt, W.A.; Mickley, G.A.

    1988-04-01

    Exposure of rats to 1-15 Gy gamma radiation (/sup 60/Co) induced hyperthermia, whereas 20-200 Gy induced hypothermia. Exposure either to the head or to the whole body to 10 Gy induced hyperthermia, while body-only exposure produced hypothermia. This observation indicates that radiation-induced fever is a result of a direct effect on the brain. The hyperthermia due to 10 Gy was significantly attenuated by the pre- or post-treatment with a cyclooxygenase inhibitor, indomethacin. Hyperthermia was also altered by the central administration of a mu-receptor antagonist naloxone but only at low doses of radiation. These findings suggest that radiation-induced hyperthermia may be mediated through the synthesis and release of prostaglandins in the brain and to a lesser extent to the release of endogenous opioid peptides. The release of histamine acting on H1 and H2 receptors may be involved in radiation-induced hypothermia, since both the H1 receptor antagonist, mepyramine, and H2 receptor antagonist, cimetidine, antagonized the hypothermia. The results of these studies suggest that the release of neurohumoral substances induced by exposure to ionizing radiation is dose dependent and has different consequences on physiological processes such as the regulation of body temperature. Furthermore, the antagonism of radiation-induced hyperthermia by indomethacin may have potential therapeutic implications in the treatment of fever resulting from accidental irradiations.

  3. Non-imidazole-based histamine H3 receptor antagonists with anticonvulsant activity in different seizure models in male adult rats

    Directory of Open Access Journals (Sweden)

    Sadek B

    2016-11-01

    Full Text Available Bassem Sadek,1 Ali Saad,1 Gniewomir Latacz,2 Kamil Kuder,2 Agnieszka Olejarz,2 Tadeusz Karcz,2 Holger Stark,3 Katarzyna Kieć-Kononowicz2 1Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates; 2Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, Kraków, Poland; 3Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University, Düsseldorf, Germany Abstract: A series of twelve novel non-imidazole-based ligands (3–14 was developed and evaluated for its in vitro binding properties at the human histamine H3 receptor (hH3R. The novel ligands were investigated for their in vivo protective effects in different seizure models in male adult rats. Among the H3R ligands (3–14 tested, ligand 14 showed significant and dose-dependent reduction in the duration of tonic hind limb extension in maximal electroshock (MES-induced seizure model subsequent to acute systemic administration (5, 10, and 20 mg/kg, intraperitoneally, whereas ligands 4, 6, and 7 without appreciable protection in MES model were most promising in pentylenetetrazole (PTZ model. Moreover, the protective effect observed for ligand 14 in MES model was lower than that observed for the reference drug phenytoin and was entirely abrogated when rats were co-administered with the brain-penetrant H1R antagonist pyrilamine (PYR but not the brain-penetrant H2R antagonist zolantidine (ZOL, demonstrating that histaminergic neurotransmission by activation of postsynaptically located H1Rs seems to be involved in the protective action. On the contrary, PYR and ZOL failed to abrogate the full protection provided by 4 in PTZ model and the moderate protective effect by 14 in strychnine (STR model. Moreover, the experimental and in silico estimation of properties such as metabolism was

  4. Selective potentiation of histamine H1-receptor stimulated calcium responses by 1,4-dithiothreitol in DDT1MF-2 cells.

    Science.gov (United States)

    Dickenson, J M; Hill, S J

    1994-11-01

    The effect of 1,4-dithiothreitol (DTT) on agonist-stimulated increases in intracellular free calcium concentration ([Ca2+]i) has been investigated in the smooth muscle cell line, DDT1MF-2, derived from hamster vas deferens. Pretreatment with DTT (1 mM) produced a large leftward parallel shift in concentration-response curve for histamine H1-receptor mediated increases in [Ca2+]i. The EC50 values for H1-receptor stimulated increases in [Ca2+]i in the absence and presence of DTT were 11.3 +/- 1.5 microM (N = 6) and 0.52 +/- 0.15 microM (N = 6), respectively. DTT had no significant effect on the maximum Ca2+ response elicited by histamine (100 microM). In the presence of DTT the partial H1-receptor agonist 2-pyridylethylamine (100 microM) increased [Ca2+]i from 112 +/- 14 nM to 237 +/- 24 nM (N = 10). In control cells 2-pyridylethylamine (100 microM) did not elicit a Ca2+ response. DTT had no significant effect on the maximum Ca2+ response elicited by 1 mM 2-pyridylethylamine. The enhancement of histamine H1-receptor Ca2+ responses by DTT was reversed by the sulphydryl oxidizing agent dithiobis-(2-nitrobenzoic acid). DTT had no significant effect on adenosine A1-, bradykinin and ATP-receptor stimulated increases in [Ca2+]i. [3H]mepyramine binding experiments confirmed that DTT increased agonist affinity. DTT produced a small, but significant, leftward shift in concentration-response curve for histamine displacement of [3H]mepyramine binding. These data suggest that DTT potentiates H1-receptor mediated Ca2+ responses by increasing agonist affinity.

  5. The prototypical histamine H3 receptor inverse agonist thioperamide improves multiple aspects of memory processing in an inhibitory avoidance task.

    Science.gov (United States)

    Charlier, Yana; Brabant, Christian; Serrano, Maria Elisa; Lamberty, Yves; Tirelli, Ezio

    2013-09-15

    Numerous studies have found that histamine plays a major role in memory and that the histamine H3 receptor (H3R) inverse agonist thioperamide improves cognitive performance in various animal models. However, little is known about the stages of memory that are specifically affected by thioperamide. The purpose of the present study was to investigate the effects of thioperamide on acquisition, consolidation and retrieval processes in a one-trial inhibitory avoidance task in female C57BL/6J mice. In addition, potential state-dependency effects were studied by injecting thioperamide before the training and the test sessions in order to induce similar physiological states during acquisition and retrieval. Our results indicate that post-training systemic administration of thioperamide facilitated consolidation. Moreover, the administration of thioperamide before the training session had no effect on latency to enter the black compartment during training but enhanced memory during the retention test. The administration of thioperamide before the retention test also increased performance, which indicates that this compound ameliorates memory retrieval. Finally, when animals received thioperamide before the training session and before the retention test, the cognitive enhancing effects of thioperamide were not significantly changed. Together, our results show that thioperamide improves cognitive performance in an inhibitory avoidance task through actions on different memory stages. Furthermore, inducing a similar physiological state with thioperamide during acquisition and retrieval do not significantly affect cognitive enhancement. Our results suggest that the blockade of H3R can be helpful for the treatment of neuropsychiatric conditions characterized by deficits affecting several stages of memory processing. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Evaluation of the binding characteristics of [{sup 18}F]fluoroproxyfan in the rat brain for in vivo visualization of histamine H{sub 3} receptor

    Energy Technology Data Exchange (ETDEWEB)

    Funaki, Yoshihito [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan)], E-mail: zen@cyric.tohoku.ac.jp; Sato, Kimihiko [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Kato, Motohisa [Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan); Ishikawa, Yoichi; Iwata, Ren [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Yanai, Kazuhiko [Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan)

    2007-11-15

    Histamine H{sub 3} receptors play an important role in biological functions. The aim of this research was to examine whether histamine H{sub 3} receptors can be visualized in vivo and in vitro with [{sup 18}F]3-(1H-imidazol-4-yl)propyl 4-fluorobenzyl ether (fluoroproxyfan). [{sup 18}F]Fluoroproxyfan was synthesized with high specific activity using [{sup 18}F]benzyl bromide. The binding of [{sup 18}F]fluoroproxyfan to rat brain homogenates was higher in the striatum and thalamus and was lowest in the cerebellum. The in vitro autoradiographic study successfully demonstrated the specific binding of [{sup 18}F]fluoroproxyfan to the H{sub 3} receptor in the rat brain. In accordance with the in vitro bindings, the in vivo distribution of [{sup 18}F]fluoroproxyfan was heterogeneous in the rat brain. In the blocking experiments, the heterogeneous distribution disappeared in the presence of large amounts of fluoroproxyfan. These data suggest that [{sup 18}F]fluoroproxyfan can be potentially useful to image histamine H{sub 3} receptor noninvasively in the human brain by positron emission tomography.

  7. H. pylori acutely inhibits gastric secretion by activating CGRP sensory neurons coupled to stimulation of somatostatin and inhibition of histamine secretion.

    Science.gov (United States)

    Zaki, Muhammad; Coudron, Philip E; McCuen, Robert W; Harrington, Leslie; Chu, Shijian; Schubert, Mitchell L

    2013-04-15

    Acute Helicobacter pylori infection produces hypochlorhydria. The decrease in acid facilitates survival of the bacterium and its colonization of the stomach. The present study was designed to identify the pathways in oxyntic mucosa by which acute H. pylori infection inhibits acid secretion. In rat fundic sheets in an Ussing chamber, perfusion of the luminal surface with H. pylori in spent broth (10(3)-10(8) cfu/ml) or spent broth alone (1:10(5) to 1:10(0) final dilution) caused a concentration-dependent increase in somatostatin (SST; maximal: 200 ± 20 and 194 ± 9% above basal; P < 0.001) and decrease in histamine secretion (maximal: 45 ± 5 and 48 ± 2% below basal; P < 0.001); the latter was abolished by SST antibody, implying that changes in histamine secretion reflected changes in SST secretion. Both responses were abolished by the axonal blocker tetrodotoxin (TTX), the sensory neurotoxin capsaicin, or the CGRP antagonist CGRP8-37, implying that the reciprocal changes in SST and histamine secretion were due to release of CGRP from sensory neurons. In isolated rabbit oxyntic glands, H. pylori inhibited basal and histamine-stimulated acid secretion in a concentration-dependent manner; the responses were not affected by TTX or SST antibody, implying that H. pylori can directly inhibit parietal cell function. In conclusion, acute administration of H. pylori is capable of inhibiting acid secretion directly as well as indirectly by activating intramural CGRP sensory neurons coupled to stimulation of SST and inhibition of histamine secretion. Activation of neural pathways provides one explanation as to how initial patchy colonization of the superficial gastric mucosa by H. pylori can acutely inhibit acid secretion.

  8. A new crystal structure fragment-based pharmacophore method for G protein-coupled receptors

    DEFF Research Database (Denmark)

    Fidom, Kimberley; Isberg, Vignir; Hauser, Alexander Sebastian

    2015-01-01

    We have developed a new method for the building of pharmacophores for G protein-coupled receptors, a major drug target family. The method is a combination of the ligand- and target-based pharmacophore methods and founded on the extraction of structural fragments, interacting ligand moiety...... for new targets. A validating retrospective virtual screening of histamine H1 and H3 receptor pharmacophores yielded area-under-the-curves of 0.88 and 0.82, respectively. The fragment-based method has the unique advantage that it can be applied to targets for which no (homologous) crystal structures...... and receptor residue pairs, from crystal structure complexes. We describe the procedure to collect a library with more than 250 fragments covering 29 residue positions within the generic transmembrane binding pocket. We describe how the library fragments are recombined and inferred to build pharmacophores...

  9. Histamine and astrocyte function.

    Science.gov (United States)

    Jurič, Damijana M; Kržan, Mojca; Lipnik-Stangelj, Metoda

    2016-09-01

    Astrocytes support the brain through numerous functional interactions in health and disease. The recent advances in our knowledge of astrocyte involvement in various neurological disorders raised up several questions about their role and functioning in the central nervous system. From the evidence discussed in this review, we show that histamine importantly influences the main astrocytic activities such as ion homeostasis, energy metabolism, neurotransmitter clearance, neurotrophic activity and immune response. These processes are mediated through at least three histamine receptor subtypes, H1, H2 and H3, expressed on the astrocyte surface. Thus, we recognize histamine as an important player in the modulation of astrocytic functions that deserves further considerations in exploring involvement of astrocytes in neurological disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Histamine immunocytochemistry

    DEFF Research Database (Denmark)

    Jacobi, H H; Johansson, O; Liang, Y

    2000-01-01

    We report that basophils in peripheral blood can be stained using histamine immunocytochemistry. The staining is based on the fixation of leucocytes with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (CDI) and the subsequent incubation of these cells with antisera raised against histamine...... conjugated to different carrier proteins using CDI. The staining appears to be specific for basophils and stained cells can be examined using both fluorescence microscopy and flow cytometry. In addition, histamine immunocytochemistry can be combined with conventional immunocytochemistry by incubating...... leucocytes with antibodies to cell surface antigens prior to or following fixation of the cells with CDI. Thus, histamine immunocytochemistry may be a valuable tool in future studies of human basophils....

  11. PPI versus Histamine H2 Receptor Antagonists for Prevention of Upper Gastrointestinal Injury Associated with Low-Dose Aspirin: Systematic Review and Meta-analysis

    OpenAIRE

    Chen Mo; Gang Sun; Yan-Zhi Wang; Ming-Liang Lu; Yun-Sheng Yang

    2015-01-01

    This study compared proton pump inhibitors (PPIs) and histamine H2 receptor antagonists (H2RAs) for prevention of low-dose aspirin (LDA)-related gastrointestinal (GI) erosion, ulcer and bleeding. Electronic databases including PubMed, Embase, Cochrane Central Register of Controlled Trials, Chinese National Knowledge Infrastructure, Chinese Biomedical Literature Database, and WanFang Data were searched from the date of their establishment to December 31, 2013. Randomized controlled trials comp...

  12. Allergic manifestations and cutaneous histamine responses in patients with McCune Albright syndrome.

    Science.gov (United States)

    Jacobson, Jill D; Turpin, Angela L; Sands, Scott A

    2013-05-01

    McCune Albright syndrome (MAS) is a rare disorder characterized by precocious puberty, café-au-lait spots, and fibrous dysplasia. Its cause is an activating mutation in the GNAS gene, encoding a subunit of the stimulatory G protein, Gsalpha (Gsα). The action of any mediator that signals via Gsα and cyclic AMP can be up regulated in MAS. We had observed gastritis, gastroesophageal reflux, and anaphylaxis in McCune Albright patients. As histamine is known to signal via histamine 1 (H1) and histamine 2 (H2) receptors, which couple with stimulatory G proteins, we attempted to mechanistically link histamine responsiveness to the activating GNAS mutation. We hypothesized that responsiveness to histamine skin testing would differ between MAS patients and healthy controls. After obtaining informed consent, we performed a systematic review of histamine responsiveness and allergic manifestations in 11 MAS patients and 11 sex-matched, Tanner-stage matched controls. We performed skin prick testing, quantifying the orthogonal diameters of wheals and erythema. We also quantitated G protein mRNA expression. The peak wheal and flare responses to histamine were significantly higher in MAS patients compared to controls. This study suggests that MAS patients may be at risk for exaggerated histamine responsiveness compared to unaffected controls.

  13. Exploring polyamine regulation by nascent histamine in a human-transfected cell model.

    Science.gov (United States)

    Abrighach, H; Fajardo, I; Sánchez-Jiménez, F; Urdiales, J L

    2010-02-01

    There are multiple lines of evidence suggesting interplay between histamine and polyamines in several mammalian cell types. However, the complex metabolic context makes it difficult to elucidate the mechanisms involved. Histamine's effects can be elicited after its binding to any of the four subtypes of G-protein coupled histamine membrane receptors. In addition, intracellular histamine can also interfere with polyamine metabolism, since there are several metabolic connections between the synthesis and degradation pathways of both types of amines. In order to dissect the metabolic effects of intracellular histamine on polyamine metabolism, we chose a well-known cell culture line, i.e., the human embryonic kidney 293 cells (HEK-293 cells). Initially, we show that HEK-293 cells lack a polyamine metabolic response to extracellular histamine, even over a wide range of histamine concentrations. HEK-293 cells were transfected with active and inactive versions of human histidine decarboxylase, and changes in many of the overlapping metabolic factors and limiting steps were tested. Overall, the results indicate a regulatory effect of histamine on the post-transcriptional expression of ornithine decarboxylase and suggest that this effect is primarily responsible for the decrease in polyamine synthesis and partial blockade of cell-cycle progression, which should affect cell proliferation rate.

  14. Small mouse cholangiocytes proliferate in response to H1 histamine receptor stimulation by activation of the IP3/CaMK I/CREB pathway.

    Science.gov (United States)

    Francis, Heather; Glaser, Shannon; Demorrow, Sharon; Gaudio, Eugenio; Ueno, Yoshiyuki; Venter, Julie; Dostal, David; Onori, Paolo; Franchitto, Antonio; Marzioni, Marco; Vaculin, Shelley; Vaculin, Bradley; Katki, Khurshed; Stutes, Monique; Savage, Jennifer; Alpini, Gianfranco

    2008-08-01

    Cholangiopathies are characterized by the heterogeneous proliferation of different-sized cholangiocytes. Large cholangiocytes proliferate by a cAMP-dependent mechanism. The function of small cholangiocytes may depend on the activation of inositol trisphosphate (IP(3))/Ca(2+)-dependent signaling pathways; however, data supporting this speculation are lacking. Four histamine receptors exist (HRH1, HRH2, HRH3, and HRH4). In several cells: 1) activation of HRH1 increases intracellular Ca(2+) concentration levels; and 2) increased [Ca(2+)](i) levels are coupled with calmodulin-dependent stimulation of calmodulin-dependent protein kinase (CaMK) and activation of cAMP-response element binding protein (CREB). HRH1 agonists modulate small cholangiocyte proliferation by activation of IP(3)/Ca(2+)-dependent CaMK/CREB. We evaluated HRH1 expression in cholangiocytes. Small and large cholangiocytes were stimulated with histamine trifluoromethyl toluidide (HTMT dimaleate; HRH1 agonist) for 24-48 h with/without terfenadine, BAPTA/AM, or W7 before measuring proliferation. Expression of CaMK I, II, and IV was evaluated in small and large cholangiocytes. We measured IP(3), Ca(2+) and cAMP levels, phosphorylation of CaMK I, and activation of CREB (in the absence/presence of W7) in small cholangiocytes treated with HTMT dimaleate. CaMK I knockdown was performed in small cholangiocytes stimulated with HTMT dimaleate before measurement of proliferation and CREB activity. Small and large cholangiocytes express HRH1, CaMK I, and CaMK II. Small (but not large) cholangiocytes proliferate in response to HTMT dimaleate and are blocked by terfenadine (HRH1 antagonist), BAPTA/AM, and W7. In small cholangiocytes, HTMT dimaleate increased IP(3)/Ca(2+) levels, CaMK I phosphorylation, and CREB activity. Gene knockdown of CaMK I ablated the effects of HTMT dimaleate on small cholangiocyte proliferation and CREB activation. The IP(3)/Ca(2+)/CaMK I/CREB pathway is important in the regulation of small

  15. Preclinical evaluation of the abuse potential of Pitolisant, a histamine H3 receptor inverse agonist/antagonist compared with Modafinil

    Science.gov (United States)

    Uguen, M; Perrin, D; Belliard, S; Ligneau, X; Beardsley, PM; Lecomte, JM; Schwartz, JC

    2013-01-01

    Background and Purpose Pitolisant, a histamine H3 receptor inverse agonist/antagonist is currently under Phase III clinical trials for treatment of excessive daytime sleepiness namely in narcoleptic patients. Its drug abuse potential was investigated using in vivo models in rodents and monkeys and compared with those of Modafinil, a psychostimulant currently used in the same indications. Experimental Approach Effects of Pitolisant on dopamine release in the nucleus accumbens, on spontaneous and cocaine-induced locomotion, locomotor sensitization were monitored. It was also tested in three standard drug abuse tests i.e. conditioned place preference in rats, self-administration in monkeys and cocaine discrimination in mice as well as in a physical dependence model. Key Results Pitolisant did not elicit any significant changes in dopaminergic indices in rat nucleus accumbens whereas Modafinil increased dopamine release. In rodents, Pitolisant was without any effect on locomotion and reduced the cocaine-induced hyperlocomotion. In addition, no locomotor sensitization and no conditioned hyperlocomotion were evidenced with this compound in rats whereas significant effects were elicited by Modafinil. Finally, Pitolisant was devoid of any significant effects in the three standard drug abuse tests (including self-administration in monkeys) and in the physical dependence model. Conclusions and Implications No potential drug abuse liability for Pitolisant was evidenced in various in vivo rodent and primate models, whereas the same does not seem so clear in the case of Modafinil. PMID:23472741

  16. Carnosine protects brain microvascular endothelial cells against rotenone-induced oxidative stress injury through histamine H₁ and H₂ receptors in vitro.

    Science.gov (United States)

    Zhang, Luyi; Yao, Ke; Fan, Yanying; He, Ping; Wang, Xiaofen; Hu, Weiwei; Chen, Zhong

    2012-12-01

    Although it is believed that carnosine has protective effects on various cell types, its effect on microvascular endothelial cells has not been well defined. In the present study, we investigated the protective effects of carnosine in microvascular endothelial cells using an in vitro rotenone-induced oxidative stress model. Mouse brain microvascular endothelial cells were exposed to 1 μmol/L rotenone for 18 h. In some experiments, carnosine (100 nmol/L-1 mmol/L) was added 30 min prior to rotenone exposure. When used, histamine receptor antagonists (100 nmol/L-10 μmol/L) were added 15 min before carnosine treatment. After rotenone exposure, apoptosis of microvascular cells was analysed by Hoechst 33342 staining, whereas mitochondrial membrane potential was assessed by JC-1 staining. Intracellular carnosine and histamine levels were determined using HPLC or ultra-HPLC. Over the range 1 μmol/L-1 mmol/L, carnosine concentration-dependently decreased the number of apoptotic cells after 18 h exposure to rotenone. This effect was reversed by the histamine H1 receptor antagonists pyrilamine and diphenhydramine (1 and 10 μmol/L) and the H2 receptor antagonists cimetidine (100 nmol/L-10 μmol/L) and zolatidine (10 μmol/L). α-Fluoromethylhistidine (100 μmol/L), a selective and irreversible inhibitor of histidine decarboxylase, also significantly inhibited the protective effects of carnosine. At 0.1 mmol/L, carnosine restored the decrease in mitochondrial membrane potential after 6 h exposure to 1 μmol/L rotenone and this effect was also reversed by the H1 and H2 receptor antagonists. Moreover, intracellular carnosine levels increased as early as 1 h after carnosine treatment, whereas intracellular histamine levels increased 18 h after carnosine treatment. The results of the present study indicate that carnosine protects brain microvascular endothelial cells against rotenone-induced oxidative stress injury via histamine H1 and H2 receptors. The

  17. Role of histamine H4 receptor ligands in bleomycin-induced pulmonary fibrosis.

    Science.gov (United States)

    Lucarini, Laura; Pini, Alessandro; Rosa, Arianna Carolina; Lanzi, Cecilia; Durante, Mariaconcetta; Chazot, Paul Louis; Krief, Stéphane; Schreeb, Annemarie; Stark, Holger; Masini, Emanuela

    2016-09-01

    Fibrosis of lung tissue is a disease where a chronic inflammatory process determines a pathological remodelling of lung parenchyma. The animal model obtained by intra-tracheal administration of bleomycin in C57BL/6 mice is one of the most validated murine model. Bleomycin stimulates oxidative stress and the production of pro-inflammatory mediators. Histamine H4R have recently been implicated in inflammation and immune diseases. This study was focused to investigate the effects of H4R ligands in the modulation of inflammation and in the reduction of lung fibrosis in C57BL/6 mice treated with bleomycin. C57BL/6 mice were treated with vehicle, JNJ7777120 (JNJ, selective H4R antagonist) or ST-1006 (partial H4R agonist), ST-994 (H4R neutral antagonist) and ST-1012 (inverse H4R agonist) at equimolar doses, released by micro-osmotic pumps for 21days. Airway resistance to inflation was assayed and lung samples were processed to measure malondialdehyde (TBARS); 8-hydroxy-2'-deoxyguanosine (8OHdG); myeloperoxidase (MPO); COX-2 expression and activity as markers of oxidative stress and inflammation. Fibrosis and airway remodelling were evaluated throughout transforming growth factor-β (TGF-β), percentage of positive Goblet cells, smooth muscle layer thickness determination. Our results indicated that JNJ, ST-994 and ST-1012 decreased inflammation and oxidative stress markers, i.e. the number of infiltrating leukocytes evaluated as lung tissue MPO, COX-2 expression and activity, TBARS and 8OHdG production. They also reduced the level of TGF-β, a pro-fibrotic cytokine, collagen deposition, thickness of smooth muscle layer, Goblet cells hyperplasia; resulting in a decrease of airway functional impairment. The results here reported clearly demonstrated that H4R ligands have a beneficial effect in a model of lung fibrosis in the mouse, thus indicating that H4R antagonists or inverse agonists could be a novel therapeutic strategy for lung inflammatory diseases. Copyright © 2016

  18. Analytical Methods for the Quantification of Histamine and Histamine Metabolites.

    Science.gov (United States)

    Bähre, Heike; Kaever, Volkhard

    2017-01-01

    The endogenous metabolite histamine (HA) is synthesized in various mammalian cells but can also be ingested from exogenous sources. It is involved in a plethora of physiological and pathophysiological processes. So far, four different HA receptors (H1R-H4R) have been described and numerous HAR antagonists have been developed. Contemporary investigations regarding the various roles of HA and its main metabolites have been hampered by the lack of highly specific and sensitive analytic methods for all of these analytes. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is the method of choice for identification and sensitive quantification of many low-molecular weight endogenous metabolites. In this chapter, different methodological aspects of HA quantification as well as recommendations for LC-MS/MS methods suitable for analysis of HA and its main metabolites are summarized.

  19. TASK Channels on Basal Forebrain Cholinergic Neurons Modulate Electrocortical Signatures of Arousal by Histamine

    Science.gov (United States)

    Vu, Michael T.; Du, Guizhi; Bayliss, Douglas A.

    2015-01-01

    Basal forebrain cholinergic neurons are the main source of cortical acetylcholine, and their activation by histamine elicits cortical arousal. TWIK-like acid-sensitive K+ (TASK) channels modulate neuronal excitability and are expressed on basal forebrain cholinergic neurons, but the role of TASK channels in the histamine-basal forebrain cholinergic arousal circuit is unknown. We first expressed TASK channel subunits and histamine Type 1 receptors in HEK cells. Application of histamine in vitro inhibited the acid-sensitive K+ current, indicating a functionally coupled signaling mechanism. We then studied the role of TASK channels in modulating electrocortical activity in vivo using freely behaving wild-type (n = 12) and ChAT-Cre:TASKf/f mice (n = 12), the latter lacking TASK-1/3 channels on cholinergic neurons. TASK channel deletion on cholinergic neurons significantly altered endogenous electroencephalogram oscillations in multiple frequency bands. We then identified the effect of TASK channel deletion during microperfusion of histamine into the basal forebrain. In non-rapid eye movement sleep, TASK channel deletion on cholinergic neurons significantly attenuated the histamine-induced increase in 30–50 Hz activity, consistent with TASK channels contributing to histamine action on basal forebrain cholinergic neurons. In contrast, during active wakefulness, histamine significantly increased 30–50 Hz activity in ChAT-Cre:TASKf/f mice but not wild-type mice, showing that the histamine response depended upon the prevailing cortical arousal state. In summary, we identify TASK channel modulation in response to histamine receptor activation in vitro, as well as a role of TASK channels on cholinergic neurons in modulating endogenous oscillations in the electroencephalogram and the electrocortical response to histamine at the basal forebrain in vivo. SIGNIFICANCE STATEMENT Attentive states and cognitive function are associated with the generation of γ EEG activity

  20. Evaluation of in vivo selective binding of [{sup 11}C]doxepin to histamine H{sub 1} receptors in five animal species

    Energy Technology Data Exchange (ETDEWEB)

    Ishiwata, Kiichi E-mail: ishiwata@pet.tmig.or.jp; Kawamura, Kazunori; Wang Weifang; Tsukada, Hideo; Harada, Norihiro; Mochizuki, Hideki; Kimura, Yuichi; Ishii, Kenji; Iwata, Ren; Yanai, Kazuhiko

    2004-05-01

    The specific binding of [{sup 11}C]doxepin, which has been used as a radioligand for mapping histamine H{sub 1} receptors in human brain by positron emission tomography, was evaluated in five animal species. In mice the [{sup 11}C]doxepin uptake was reduced by treatment with cold doxepin and two H{sub 1} receptor antagonists, but not with H{sub 2}/H{sub 3} antagonists. The specific binding evaluated with treatment with (+)-chlorpheniramine (H{sub 1} antagonist) was in the range of 10-30% in mouse, rat, rabbit, and monkey, but was not detected in guinea pig.

  1. Effect of carnosine on the immunosuppressive effect of histamine

    Energy Technology Data Exchange (ETDEWEB)

    Sharpan, Yu. V.

    1985-04-01

    This paper studies the ability of carnosine (beta-imidazole-lactate) to affect histamine-induced immunosuppression of proliferative activity of various lymphocyte subpopulations and the realization of this effect through surface histamine receptors of the cells. The experiments were carried out on mice; lymphocytes were incubated with tritium-labeled thymidine for 4 h, after which their radioactivity was determined on a scintillation counter. The results show that histamine has an inhibitory action on antigen-induced proliferation of T suppressor lymphocytes through H-2 histamine receptors, for this effect was considerably inhibited by the H-2 histamine blockers metiamide, but not by the H-1 histamine blocker mepyramine.

  2. G Protein-coupled Receptor Biased Agonism.

    Science.gov (United States)

    Hodavance, Sima Y; Gareri, Clarice; Torok, Rachel D; Rockman, Howard A

    2016-03-01

    G protein-coupled receptors are the largest family of targets for current therapeutics. The classic model of their activation was binary, where agonist binding induced an active conformation and subsequent downstream signaling. Subsequently, the revised concept of biased agonism emerged, where different ligands at the same G protein-coupled receptor selectively activate one downstream pathway versus another. Advances in understanding the mechanism of biased agonism have led to the development of novel ligands, which have the potential for improved therapeutic and safety profiles. In this review, we summarize the theory and most recent breakthroughs in understanding biased signaling, examine recent laboratory investigations concerning biased ligands across different organ systems, and discuss the promising clinical applications of biased agonism.

  3. Bilastine vs. hydroxyzine: occupation of brain histamine H1 -receptors evaluated by positron emission tomography in healthy volunteers.

    Science.gov (United States)

    Farré, Magí; Pérez-Mañá, Clara; Papaseit, Esther; Menoyo, Esther; Pérez, Marta; Martin, Soraya; Bullich, Santiago; Rojas, Santiago; Herance, José-Raúl; Trampal, Carlos; Labeaga, Luis; Valiente, Román

    2014-11-01

    A close correlation exists between positron emission tomography (PET)-determined histamine H1 -receptor occupancy (H1 RO) and the incidence of sedation. Antihistamines with H1 RO bilastine, a second generation antihistamine, with that of hydroxyzine. This randomized, double-blind, crossover study used PET imaging with [(11) C]-doxepin to evaluate H1 RO in 12 healthy males (mean age 26.2 years), after single oral administration of bilastine (20 mg), hydroxyzine (25 mg) or placebo. Binding potentials and H1 ROs were calculated in five cerebral cortex regions of interest: frontal, occipital, parietal, temporal, insula. Plasma bilastine concentrations, subjective sedation (visual analogue scale), objective psychomotor performance (digital symbol substitution test), physiological variables and safety (adverse events, AEs), were also evaluated. The mean binding potential of all five regions of interest (total binding potential) was significantly greater with bilastine than hydroxyzine (mean value 0.26 vs. 0.13, P bilastine and placebo. Overall H1 RO by bilastine was significantly lower than that by hydroxyzine (mean value -3.92% vs. 53.95%, P bilastine plasma concentrations and total binding potential values. No significant between-treatment differences were observed for sedation and psychomotor performance. Twenty-six non-serious AEs were reported. Sleepiness or sedation was not reported with bilastine but appeared in some subjects with hydroxyzine. A single oral dose of bilastine 20 mg had minimal H1 RO, was not associated with subjective sedation or objective impairment of psychomotor performance and was devoid of treatment-related sedative AEs, thus satisfying relevant subjective, objective and PET criteria as a non-sedating antihistamine. © 2014 The British Pharmacological Society.

  4. The association between histamine 2 receptor antagonist use and Clostridium difficile infection: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Imad M Tleyjeh

    Full Text Available BACKGROUND: Clostridium difficile infection (CDI is a major health problem. Epidemiological evidence suggests that there is an association between acid suppression therapy and development of CDI. PURPOSE: We sought to systematically review the literature that examined the association between histamine 2 receptor antagonists (H2RAs and CDI. DATA SOURCE: We searched Medline, Current Contents, Embase, ISI Web of Science and Elsevier Scopus from 1990 to 2012 for all analytical studies that examined the association between H2RAs and CDI. STUDY SELECTION: Two authors independently reviewed the studies for eligibility. DATA EXTRACTION: Data about studies characteristics, adjusted effect estimates and quality were extracted. DATA SYNTHESIS: Thirty-five observations from 33 eligible studies that included 201834 participants were analyzed. Studies were performed in 6 countries and nine of them were multicenter. Most studies did not specify the type or duration of H2RAs therapy. The pooled effect estimate was 1.44, 95% CI (1.22-1.7, I(2 = 70.5%. This association was consistent across different subgroups (by study design and country and there was no evidence of publication bias. The pooled effect estimate for high quality studies was 1.39 (1.15-1.68, I2 = 72.3%. Meta-regression analysis of 10 study-level variables did not identify sources of heterogeneity. In a speculative analysis, the number needed to harm (NNH with H2RAs at 14 days after hospital admission in patients receiving antibiotics or not was 58, 95% CI (37, 115 and 425, 95% CI (267, 848, respectively. For the general population, the NNH at 1 year was 4549, 95% CI (2860, 9097. CONCLUSION: In this rigorous systematic review and meta-analysis, we observed an association between H2RAs and CDI. The absolute risk of CDI associated with H2RAs is highest in hospitalized patients receiving antibiotics.

  5. Effect of histamine H1 and H2 receptor antagonists, microinjected into cerebellar vermis, on emotional memory consolidation in mice

    Energy Technology Data Exchange (ETDEWEB)

    Gianlorenço, A.C.L.; Serafim, K.R. [Laboratório de Neurociências, Departamento de Fisioterapia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, SP, Brasil, Laboratório de Neurociências, Departamento de Fisioterapia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, SP (Brazil); Canto-de-Souza, A. [Laboratório de Psicologia da Aprendizagem, Departamento de Psicologia, Centro de Educação e Ciências Humanas, Universidade Federal de São Carlos, São Carlos, SP, Brasil, Laboratório de Psicologia da Aprendizagem, Departamento de Psicologia, Centro de Educação e Ciências Humanas, Universidade Federal de São Carlos, São Carlos, SP (Brazil); Programa de Pós-Graduação em Ciências Fisiológicas, Universidade Federal de São Carlos, São Carlos, SP, Brasil, Programa de Pós-Graduação em Ciências Fisiológicas, Universidade Federal de São Carlos, São Carlos, SP (Brazil); Instituto de Neurociências e Comportamento, Universidade de São Paulo, Ribeirão Preto, SP, Brasil, Instituto de Neurociências e Comportamento, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Mattioli, R. [Laboratório de Neurociências, Departamento de Fisioterapia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, SP, Brasil, Laboratório de Neurociências, Departamento de Fisioterapia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, SP (Brazil)

    2014-02-17

    This study investigated the effects of histamine H1 or H2 receptor antagonists on emotional memory consolidation in mice submitted to the elevated plus maze (EPM). The cerebellar vermis of male mice (Swiss albino) was implanted using a cannula guide. Three days after recovery, behavioral tests were performed in the EPM on 2 consecutive days (T1 and T2). Immediately after exposure to the EPM (T1), animals received a microinjection of saline (SAL) or the H1 antagonist chlorpheniramine (CPA; 0.016, 0.052, or 0.16 nmol/0.1 µL) in Experiment 1, and SAL or the H2 antagonist ranitidine (RA; 0.57, 2.85, or 5.7 nmol/0.1 µL) in Experiment 2. Twenty-four hours later, mice were reexposed to the EPM (T2) under the same experimental conditions but they did not receive any injection. Data were analyzed using one-way ANOVA and the Duncan test. In Experiment 1, mice microinjected with SAL and with CPA entered the open arms less often (%OAE) and spent less time in the open arms (%OAT) in T2, and there was no difference among groups. The results of Experiment 2 demonstrated that the values of %OAE and %OAT in T2 were lower compared to T1 for the groups that were microinjected with SAL and 2.85 nmol/0.1 µL RA. However, when animals were microinjected with 5.7 nmol/0.1 µL RA, they did not show a reduction in %OAE and %OAT. These results demonstrate that CPA did not affect behavior at the doses used in this study, while 5.7 nmol/0.1 µL RA induced impairment of memory consolidation in the EPM.

  6. Non-imidazole-based histamine H3 receptor antagonists with anticonvulsant activity in different seizure models in male adult rats.

    Science.gov (United States)

    Sadek, Bassem; Saad, Ali; Latacz, Gniewomir; Kuder, Kamil; Olejarz, Agnieszka; Karcz, Tadeusz; Stark, Holger; Kieć-Kononowicz, Katarzyna

    2016-01-01

    A series of twelve novel non-imidazole-based ligands (3-14) was developed and evaluated for its in vitro binding properties at the human histamine H3 receptor (hH3R). The novel ligands were investigated for their in vivo protective effects in different seizure models in male adult rats. Among the H3R ligands (3-14) tested, ligand 14 showed significant and dose-dependent reduction in the duration of tonic hind limb extension in maximal electroshock (MES)-induced seizure model subsequent to acute systemic administration (5, 10, and 20 mg/kg, intraperitoneally), whereas ligands 4, 6, and 7 without appreciable protection in MES model were most promising in pentylenetetrazole (PTZ) model. Moreover, the protective effect observed for ligand 14 in MES model was lower than that observed for the reference drug phenytoin and was entirely abrogated when rats were co-administered with the brain-penetrant H1R antagonist pyrilamine (PYR) but not the brain-penetrant H2R antagonist zolantidine (ZOL), demonstrating that histaminergic neurotransmission by activation of postsynaptically located H1Rs seems to be involved in the protective action. On the contrary, PYR and ZOL failed to abrogate the full protection provided by 4 in PTZ model and the moderate protective effect by 14 in strychnine (STR) model. Moreover, the experimental and in silico estimation of properties such as metabolism was performed for five selected test compounds. Also, lipophilicity using planar reversed-phase thin-layer chromatography method was included for better understanding of the molecular properties of the tested compounds. Additionally, the absorption, distribution, metabolism, and elimination and toxicity parameters were evaluated for the most promising compounds 2, 4, 6, 7, and 14 utilizing in vitro methods. These interesting results highlight the potential of H3R ligands as new antiepileptic drugs or as adjuvants to available epilepsy medications.

  7. Effect of histamine H1 and H2 receptor antagonists, microinjected into cerebellar vermis, on emotional memory consolidation in mice

    Directory of Open Access Journals (Sweden)

    A.C.L. Gianlorenco

    2014-02-01

    Full Text Available This study investigated the effects of histamine H1 or H2 receptor antagonists on emotional memory consolidation in mice submitted to the elevated plus maze (EPM. The cerebellar vermis of male mice (Swiss albino was implanted using a cannula guide. Three days after recovery, behavioral tests were performed in the EPM on 2 consecutive days (T1 and T2. Immediately after exposure to the EPM (T1, animals received a microinjection of saline (SAL or the H1 antagonist chlorpheniramine (CPA; 0.016, 0.052, or 0.16 nmol/0.1 µL in Experiment 1, and SAL or the H2 antagonist ranitidine (RA; 0.57, 2.85, or 5.7 nmol/0.1 µL in Experiment 2. Twenty-four hours later, mice were reexposed to the EPM (T2 under the same experimental conditions but they did not receive any injection. Data were analyzed using one-way ANOVA and the Duncan test. In Experiment 1, mice microinjected with SAL and with CPA entered the open arms less often (%OAE and spent less time in the open arms (%OAT in T2, and there was no difference among groups. The results of Experiment 2 demonstrated that the values of %OAE and %OAT in T2 were lower compared to T1 for the groups that were microinjected with SAL and 2.85 nmol/0.1 µL RA. However, when animals were microinjected with 5.7 nmol/0.1 µL RA, they did not show a reduction in %OAE and %OAT. These results demonstrate that CPA did not affect behavior at the doses used in this study, while 5.7 nmol/0.1 µL RA induced impairment of memory consolidation in the EPM.

  8. Pharmacological Characterization of 5-Substituted 1-[(2,3-dihydro-1-benzofuran-2-ylmethyl]piperazines: Novel Antagonists for the Histamine H3 and H4 Receptors with Anti-inflammatory Potential

    Directory of Open Access Journals (Sweden)

    Michelle F. Corrêa

    2017-11-01

    Full Text Available The histamine receptors (HRs are traditional G protein-coupled receptors of extensive therapeutic interest. Recently, H3R and H4R subtypes have been targeted in drug discovery projects for inflammation, asthma, pain, cancer, Parkinson’s, and Alzheimer’s diseases, which includes searches for dual acting H3R/H4R ligands. In the present work, nine 1-[(2,3-dihydro-1-benzofuran-2-ylmethyl]piperazine (LINS01 series molecules were synthesized and evaluated as H3R and H4R ligands. Our data show that the N-allyl-substituted compound LINS01004 bears the highest affinity for H3R (pKi 6.40, while the chlorinated compound LINS01007 has moderate affinity for H4R (pKi 6.06. In addition, BRET assays to assess the functional activity of Gi1 coupling indicate that all compounds have no intrinsic activity and act as antagonists of these receptors. Drug-likeness assessment indicated these molecules are promising leads for further improvements. In vivo evaluation of compounds LINS01005 and LINS01007 in a mouse model of asthma showed a better anti-inflammatory activity of LINS01007 (3 g/kg than the previously tested compound LINS01005. This is the first report with functional data of these compounds in HRs, and our results also show the potential of their applications as anti-inflammatory.

  9. Skin mast cell histamine release following stem cell factor and high-affinity immunoglobulin E receptor cross-linking in dogs with atopic dermatitis.

    Science.gov (United States)

    Hammerberg, B; Olivry, T; Orton, S M

    2001-12-01

    Stem cell factor (SCF) influences mast cell activation and inflammatory mediator release, and is elevated in tissues undergoing allergic inflammation. Wheal formation in response to the injection of SCF or anti-immunoglobulin (Ig)E antibody injection was compared between normal (n = 10) and nonlesional atopic (n = 10) canine skin. In situ SCF secretion was compared between lesional and nonlesional skin using immunohistochemistry. Histamine release by skin cell suspensions after stimulation with SCF, concanavalin A (ConA) or rabbit anticanine IgE antibodies was compared between normal and atopic dogs. All dogs exhibited strong responses to intradermal SCF injection at 10 and 50 ng mL(-1). Atopic dogs had significantly (P = 0.002) larger wheal responses to anti-IgE than normal dogs; but there was no difference in numbers of skin mast cells bearing IgE as detected by immunohistochemistry. Only atopic dogs exhibited interstitial deposition of SCF in both lesional and nonlesional skin specimens. Median histamine release stimulated by SCF in the absence of IgE from lesional skin cells was higher in atopic than normal dogs (P = 0.04). These experiments suggest that dermal SCF secretion could potentiate histamine release following IgE receptor cross-linking and thus, could be one of the explanations for the inherent mast cell hyperexcitability observed in canine atopic dermatitis.

  10. Activation of histamine H4 receptor inhibits TNFα/IMD-0354-induced apoptosis in human salivary NS-SV-AC cells.

    Science.gov (United States)

    Stegajev, Vasili; Kouri, Vesa-Petteri; Salem, Abdelhakim; Rozov, Stanislav; Stark, Holger; Nordström, Dan C E; Konttinen, Yrjö T

    2014-12-01

    Apoptosis is involved in the pathogenesis of Sjögren's syndrome (SS), an autoimmune disease affecting exocrine glands. Our recent studies revealed diminished histamine H4 receptor (H₄R) expression and impaired histamine transport in the salivary gland epithelial cells in SS. The aim was now to test if nanomolar histamine and high-affinity H₄R signaling affect apoptosis of human salivary gland epithelial cell. Simian virus 40-immortalized acinar NS-SV-AC cells were cultured in serum-free keratinocyte medium ± histamine H₄R agonist HST-10. Expression and internalization of H₄R were studied by immunofluorescence staining ± clathrin inhibitor methyl-β-cyclodextrin (MβCD). Apoptosis induced using tumor necrosis factor-α with nuclear factor-κB inhibitor IMD-0354 was studied using phase contrast microscopy, Western blot, flow cytometry and polymerase chain reaction (qRT-PCR). HST-10-stimulated H₄R internalization was inhibited by MβCD. Western blotting revealed diminished phosphorylated c-Jun N-terminal kinase JNK, but unchanged levels of phosphorylated extracellular signal regulated kinase pERK1/2 in H₄R-stimulated samples compared to controls. qRT-PCR showed up-regulated expression of anti-apoptotic B cell lymphoma-extra large/Bcl-xL mRNAs and proteins, whereas pro-apoptotic Bcl-2-associated X protein/BAX remained unchanged in H4R-stimulated samples. H₄R stimulation diminished cleavage of PARP and flow cytometry showed significant dose-dependent inhibitory effect of H₄R stimulation on apoptosis. As far as we know this is the first study showing inhibitory effect of H₄R activation on apoptosis of human salivary gland cells. Diminished H₄R-mediated activation may contribute to loss of immune tolerance in autoimmune diseases and in SS in particular.

  11. Effects of rupatadine, a new dual antagonist of histamine and platelet-activating factor receptors, on human cardiac Kv1.5 channels

    OpenAIRE

    Caballero, Ricardo; Valenzuela, Carmen; Longobardo, Mónica; Tamargo, Juan; Delpón, Eva

    1999-01-01

    The effects of rupatadine, a new dual antagonist of both histamine H1 and platelet-activating factor receptors, were studied on human cloned hKv1.5 channels expressed in Ltk− cells using the whole-cell patch-clamp technique.Rupatadine produced a use- and concentration-dependent block of hKv1.5 channels (KD=2.4±0.7 μM) and slowed the deactivation of the tail currents, thus inducing the ‘crossover' phenomenon.Rupatadine-induced block was voltage-dependent increasing in the voltage range for cha...

  12. Conformational analysis for some nonclassical antagonists of histamine H3 receptor

    Science.gov (United States)

    Borota, Ana; Mracec, Maria; Rad, Ramona; Ostopovici, Liliana; Mracec, Mircea

    A conformational search in vacuum for a series of 1,3-substituted pyrrolidine derivatives has been performed using the AMBER, AM1, PM3, and MNDO methods. Conformational analysis of the pyrrolidine ligands suggests that these compounds could have many conformers that populate the low-energy minima on the potential energy surface (PES). The conformational space occupied by the ligands is large and, in vacuum, the rotation barriers of different flexible bonds have energies between 0.5 and thousands of kcal/mol. By optimization, most conformers have energy barriers of 0-5 kcal/mol; thus, they could interconvert easily to obtain better interactions in the receptor active site. Optimized conformers having energy barriers of >5 kcal/mol display bad geometries with very large bond lengths and deformed rings. Shapes and heights of rotation barriers obtained through COSMO-AM1 single-point calculations in water are similar to those obtained from single-point calculations in vacuum. However, in water the energy barriers are lower, allowing most conformers to convert in other low-energy conformers. The best conformers in vacuum and in water are different: the gas phase best conformer has a helical shape, while the best conformer in water has an extended shape.

  13. In vivo histamine optical nanosensors.

    Science.gov (United States)

    Cash, Kevin J; Clark, Heather A

    2012-01-01

    In this communication we discuss the development of ionophore based nanosensors for the detection and monitoring of histamine levels in vivo. This approach is based on the use of an amine-reactive, broad spectrum ionophore which is capable of recognizing and binding to histamine. We pair this ionophore with our already established nanosensor platform, and demonstrate in vitro and in vivo monitoring of histamine levels. This approach enables capturing rapid kinetics of histamine after injection, which are more difficult to measure with standard approaches such as blood sampling, especially on small research models. The coupling together of in vivo nanosensors with ionophores such as nonactin provide a way to generate nanosensors for novel targets without the difficult process of designing and synthesizing novel ionophores.

  14. HISTAMINE H3 RECEPTOR INVERSE AGONISTS ON COGNITIVE AND MOTOR PROCESSES: RELEVANCE TO ALZHEIMER’S DISEASE, ADHD, SCHIZOPHRENIA AND DRUG ABUSE

    Directory of Open Access Journals (Sweden)

    Divya eVohora

    2012-10-01

    Full Text Available Histamine H3 receptor antagonists/ inverse agonists possess potential to treat diverse disease states of the central nervous system (CNS. Cognitive dysfunction and motor impairments are the hallmark of multifarious neurodegenerative and/or psychiatric disorders. This review presents the various neurobiological/ neurochemical evidences available so far following H3 receptor inverse agonists/ antagonists in the pathophysiology of Alzheimer’s disease (AD, attention-deficit hyperactivity disorder (ADHD, schizophrenia and drug abuse each of which is accompanied by deficits of some aspects of cognitive and/or motor functions. Whether the H3 receptor inverse agonism modulates the neurochemical basis underlying the disease condition or affects only the cognitive/motor component of the disease process is discussed with the aim to provide a rationale for their use in diverse disease states that are interlinked and are accompanied by some common motor, cognitive and attentional deficits.

  15. Review: Vascular Effects of Histamine | Ebeigbe | Nigerian Journal ...

    African Journals Online (AJOL)

    Four subtypes of receptors (HFour subtypes of receptors (H1, H2, H3 and H4) mediate the actions of histamine. In the vascular wall, the effects of histamine are mediated via H1 and H2 receptors and the actions are modulated by H3 receptor subtype located on presynaptic neurones. Alterations in vascular responses to ...

  16. [11C]Doxepin binding to histamine H1 receptors in living human brain in association with attentive waking and circadian rhythm

    Directory of Open Access Journals (Sweden)

    Kazuhiko eYanai

    2012-06-01

    Full Text Available Molecular imaging in neuroscience is a new research field that enables visualization of the impact of molecular events on brain structure and function in humans. While magnetic resonance-based imaging techniques can provide complex information at the level of system, positron emission tomography (PET enables determination of the distribution and density of receptor and enzyme in the human brain. Previous studies using [11C]raclopride revealed that the release of neuronal dopamine was increased in human brain by psychostimulants or reward stimuli. Following on from these previous studies, we examined whether the levels of neuronal release of histamine might change [11C]doxepin binding to the H1 receptors under the influence of physiological stimuli. The purpose of the present study was to evaluate the test-retest reliability of quantitative measurement of [11C]doxepin binding between morning and afternoon and between resting and attentive waking conditions in healthy human subjects. There was a trend for a decrease in [11C]doxepin binding during attentive calculation tasks compared with that in resting conditions, but the difference (approximately 10% was not significant. In contrast, the binding potential of [11C]doxepin in the anterior cingulate gyrus was significantly higher in the morning than that in the afternoon (approximately 19%, suggesting that higher histamine release in the morning would decrease the [11C]doxepin binding in the afternoon. This study suggests that non-invasive measurement of neuronal histamine release is feasible in humans by PET ligand-activation study, although the development of a tracer with better signal-to-noise properties is needed.

  17. Histamine regulates murine primary dendritic cell functions.

    Science.gov (United States)

    Schenk, Heiko; Neumann, Detlef; Kloth, Christina

    2016-10-01

    The modulation of antigen uptake and activation of dendritic cells (DCs) by histamine may function as a regulator of inflammation. Therefore, we sought to determine the impact of histamine on antigen uptake by and activation of murine DCs. DCs from spleen and lung were either identified by flow cytometry or were immunomagnetically enriched. Cells were stimulated with histamine, and the regulation of MHC-II and co-stimulatory molecule expression (CD80, CD86, and ICOS-L) and antigen uptake were quantified by flow cytometry. Individual contributions of the histamine receptor subtypes were determined by using the antagonists mepyramine (histamine H1-receptor: H1R), famotidine (H2R), and JNJ 7777120 (H4R). Histamine accelerated the uptake of soluble antigen via the H1R, H2R, and H4R in splenic DCs. Co-stimulatory molecule expression was enhanced already by enrichment procedures, thus, the analyses were performed in unseparated cell populations. Histamine enhanced the expression of CD86 and ICOS-L while expression of CD80 was unaffected. Antagonism at H1R, H2R, and H4R and at H1R and H4R reduced the histamine-induced enhanced expression of CD86 and ICOS-L, respectively. Histamine contributes to the regulation of the immunological synapse by stimulation of antigen uptake and activation of DCs via H1R, H2R, and H4R.

  18. Resolvin D1 and Aspirin-Triggered Resolvin D1 Regulate Histamine-stimulated Conjunctival Goblet Cell Secretion

    Science.gov (United States)

    Li, Dayu; Hodges, Robin R.; Jiao, Jianwei; Carozza, Richard B.; Shatos, Marie A.; Chiang, Nan; Serhan, Charles N.; Dartt, Darlene A.

    2013-01-01

    Resolution of inflammation is an active process mediated by pro-resolution lipid mediators. Since resolvin (Rv) D1 is produced in the cornea, pro-resolution mediators could be effective in regulating inflammatory responses to histamine in allergic conjunctivitis. Two key mediators of resolution are the D-series resolvins RvD1 or aspirin-triggered RvD1 (AT-RvD1). We used cultured conjunctival goblet cells to determine whether histamine actions can be terminated during allergic responses. We found cross-talk between two types of G protein-coupled receptors, as RvD1 interacts with its receptor GPR32 to block histamine-stimulated H1 receptor increases in intracellular [Ca2+] ([Ca2+]i) preventing H1 receptor-mediated responses. In human and rat conjunctival goblet cells RvD1 and AT-RvD1 each block histamine-stimulated secretion by preventing its increase in [Ca2+]i and activation of extracellular regulated protein kinase (ERK)1/2. We suggest that D-series resolvins regulate histamine responses in the eye and offer new treatment approaches for allergic conjunctivitis or other histamine-dependent pathologies. PMID:23462912

  19. Resolvin D1 and aspirin-triggered resolvin D1 regulate histamine-stimulated conjunctival goblet cell secretion.

    Science.gov (United States)

    Li, D; Hodges, R R; Jiao, J; Carozza, R B; Shatos, M A; Chiang, N; Serhan, C N; Dartt, D A

    2013-11-01

    Resolution of inflammation is an active process mediated by pro-resolution lipid mediators. As resolvin (Rv) D1 is produced in the cornea, pro-resolution mediators could be effective in regulating inflammatory responses to histamine in allergic conjunctivitis. Two key mediators of resolution are the D-series resolvins RvD1 or aspirin-triggered RvD1 (AT-RvD1). We used cultured conjunctival goblet cells to determine whether histamine actions can be terminated during allergic responses. We found cross-talk between two types of G protein-coupled receptors (GPRs), as RvD1 interacts with its receptor GPR32 to block histamine-stimulated H1 receptor increases in intracellular [Ca(2+)] ([Ca(2+)]i) preventing H1 receptor-mediated responses. In human and rat conjunctival goblet cells, RvD1 and AT-RvD1 each block histamine-stimulated secretion by preventing its increase in [Ca(2+)]i and activation of extracellular regulated-protein kinase (ERK)1/2. We suggest that D-series resolvins regulate histamine responses in the eye and offer new treatment approaches for allergic conjunctivitis or other histamine-dependent pathologies.

  20. Are basophil histamine release and high affinity IgE receptor expression involved in asymptomatic skin sensitization?

    DEFF Research Database (Denmark)

    Jensen, Bettina Margrethe; Assing, K; Jensen, Lone Hummelshøj

    2006-01-01

    . However, a relationship between the AS status and FcepsilonRI has not been investigated. We aimed to characterize basophils from AS by looking at histamine release (HR) (sensitivity and reactivity) and the FcepsilonRI molecule, and compare it with nonatopic (NA) or allergic (A) persons....

  1. Cost-Effectiveness of Histamine2 Receptor Antagonists Versus Proton Pump Inhibitors for Stress Ulcer Prophylaxis in Critically Ill Patients.

    Science.gov (United States)

    Hammond, Drayton A; Kathe, Niranjan; Shah, Anuj; Martin, Bradley C

    2017-01-01

    To determine the cost-effectiveness of stress ulcer prophylaxis with histamine2 receptor antagonists (H2RAs) versus proton pump inhibitors (PPIs) in critically ill and mechanically ventilated adults. A decision analytic model estimating the costs and effectiveness of stress ulcer prophylaxis (with H2RAs and PPIs) from a health care institutional perspective. Adult mixed intensive care unit (ICU) population who received an H2RA or PPI for up to 9 days. Effectiveness measures were mortality during the ICU stay and complication rate. Costs (2015 U.S. dollars) were combined to include medication regimens and untoward events associated with stress ulcer prophylaxis (pneumonia, Clostridium difficile infection, and stress-related mucosal bleeding). Costs and probabilities for complications and mortality from complications came from randomized controlled trials and observational studies. A base case scenario was developed with pooled data from an observational study and meta-analysis of randomized controlled trials. Scenarios based on observational and meta-analysis data alone were evaluated. Outcomes were expected and incremental costs, mortalities, and complication rates. Univariate sensitivity analyses were conducted to determine the influence of inputs on cost, mortality, and complication rates. Monte Carlo simulations evaluated second-order uncertainty. In the base case scenario, the costs, complication rates, and mortality rates were $9039, 17.6%, and 2.50%, respectively, for H2RAs and $11,249, 22.0%, and 3.34%, respectively, for PPIs, indicating that H2RAs dominated PPIs. The observational study-based model provided similar results; however, in the meta-analysis-based model, H2RAs had a cost of $8364 and mortality rate of 3.2% compared with $7676 and 2.0%, respectively, for PPIs. At a willingness-to-pay threshold of $100,000/death averted, H2RA therapy was superior or preferred 70.3% in the base case and 97.0% in the observational study-based scenario. PPI therapy

  2. Histamine fish poisoning

    Directory of Open Access Journals (Sweden)

    M. Nosić

    2010-01-01

    Full Text Available Histamine fish poisoning is a chemical intoxication associated with intake of fishes with high histamine content. Histamine is developed in fish tissue post mortem due to bacterial decarboxilation of free amino-acid histidine. This paper deals with causes of histamine development in fish meat and with histamine influence on human health. Prevention of histamine fish poisoning would also be discussed. The case histories of histamine food poisoning in our country and in the world would be described. Histamine levels used in Regulation would be presented.

  3. Association of genetic variants of the histamine H1 and muscarinic M3 receptors with BMI and HbA1c values in patients on antipsychotic medication.

    Science.gov (United States)

    Vehof, Jelle; Risselada, Arne J; Al Hadithy, Asmar F Y; Burger, Huibert; Snieder, Harold; Wilffert, Bob; Arends, Johan; Wunderink, Lex; Knegtering, Henrikus; Wiersma, Durk; Cohen, Dan; Mulder, Hans; Bruggeman, Richard

    2011-07-01

    Antipsychotic affinity for the histamine H1 receptor and the muscarinic M3 receptor have been associated with the side effects weight gain, and development of diabetes, respectively. We investigated polymorphisms of the histamine H1 (HRH1) and muscarinic acetylcholine receptor M3 (CHRM3) receptor genes for an association with body mass index (BMI) and glycated hemoglobin (HbA1c). We included 430 Caucasian patients with a non-affective psychotic disorder using antipsychotics for at least 3 months. Primary endpoints of the study were cross-sectionally measured BMI and HbA1c; secondary endpoints were obesity and hyperglycaemia. Two single-nucleotide polymorphisms (SNPs) in the HRH1 gene, rs346074 and rs346070, and one SNP in the CHRM3 gene, rs3738435, were genotyped. Our primary hypothesis in this study was an interaction between genotype on BMI and antipsychotic affinity for the H1 and M3 receptor. A significant association of interaction between haplotype rs346074-rs346070 and BMI (p value 0.025) and obesity (p value 0.005) in patients using high-H1 affinity antipsychotics versus patients using low-H1 affinity antipsychotics was found. There was no association of CHRM3 gene variant rs3738435 with BMI, and we observed no association with HbA1c or hyperglycaemia in any of the variants. This study, for the first time, demonstrates a significant association between HRH1 variants and BMI in patients with a psychotic disorder using antipsychotics. In future, genotyping of HRH1 variants may help predicting weight gain in patients using antipsychotics.

  4. Determination of Histamine in Silages Using Nanomaghemite Core (γ-Fe2O3-Titanium Dioxide Shell Nanoparticles Off-Line Coupled with Ion Exchange Chromatography

    Directory of Open Access Journals (Sweden)

    Natalia Cernei

    2016-09-01

    Full Text Available The presence of biogenic amines is a hallmark of degraded food and its products. Herein, we focused on the utilization of magnetic nanoparticles off-line coupled with ion exchange chromatography with post-column ninhydrin derivatization and Vis detection for histamine (Him separation and detection. Primarily, we described the synthesis of magnetic nanoparticles with nanomaghemite core (γ-Fe2O3 functionalized with titanium dioxide and, then, applied these particles to specific isolation of Him. To obtain further insight into interactions between paramagnetic particles’ (PMP surface and Him, a scanning electron microscope was employed. It was shown that binding of histamine causes an increase of relative current response of deprotonated PMPs, which confirmed formation of Him-PMPs clusters. The recovery of the isolation showed that titanium dioxide-based particles were able to bind and preconcentrate Him with recovery exceeding 90%. Finally, we successfully carried out the analyses of real samples obtained from silage. We can conclude that our modified particles are suitable for Him isolation, and thus may serve as the first isolation step of Him from biological samples, as it is demonstrated on alfalfa seed variety Tereza silage.

  5. Histamine 2 blocker potentiates the effects of histamine 1 blocker in suppressing histamine-induced wheal

    Directory of Open Access Journals (Sweden)

    Dhanya N

    2008-01-01

    Full Text Available Background : Histamine is responsible for the wheal and flare reaction in various allergic conditions. Classical antihistamines are the drugs which block the H 1 receptors and are widely used in various allergic conditions, whereas H 2 blockers are mainly used for acid peptic disease. Although H 1 receptor-mediated actions of histamine are primarily responsible for vasodilatation, vasopermeability, and itching, it has been observed that combined blocking of both H 1 and H 2 receptors may provide better relief. Aim: To compare the efficacy of levocetirizine (H 1 blocker versus levocetirizine and ranitidine (H 2 blocker in suppressing histamine-induced wheal. Methods: Fifteen volunteers were given a single dose of levocetirizine 5 mg on day 1 and a single dose of levocetirizine 5 mg with ranitidine 150 mg twice a day on day 7. A pretest was performed by intradermal histamine prick test. After administration of the drugs, the prick test was repeated at 1 hour, 2, 3, 6, and 24 hours, and the size of the wheal measured and statistically analyzed. Results: At 1 hour, there was no statistically significant difference in the wheal size between levocetirizine alone and the combination of levocetirizine and ranitidine. Levocetirizine with ranitidine resulted in statistically significant reduction of wheal size at 2, 3, 6, and 24 hours when compared with levocetirizine alone. Conclusion: H2 blocker potentiates the effects of an H1 blocker in suppressing histamine-induced wheal.

  6. Effects of H[sub 1]-receptor antagonists on [sup 14]C-aminopyrine accumulated in histamine-stimulated rabbit gastric glands

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, G.; Romell, B.; Girma, K.; Seensalu, R. (Swedish Univ. of Agricultural Science, Uppsala (Sweden))

    1993-01-01

    After stimulation of gastric acid production there is a considerable delay before the acid starts to appear in the gastric lumen. The present study was carried out on isolated gastric glands to test the hypothesis that there may be a mechanisms in the parietal cell that contributes to this delay by preventing emptying of the secretory canaliculi. Glands were incubated with [sup 14]C-aminopyrine and stimulated with histamine. After accumulation of [sup 14]C-aminopyrine, various concentration of H[sub 1]-receptor antagonists were added. Clemastine, promethazine, and hydroxyzine effectively and cetirizine and tripelennamine less effectively decreased the accumulated [sup 14]C-aminopyrine content in a dose-dependent manner without significantly reducing the oxygen consumption. The H[sub 1]-receptor antagonists influenced the [sup 14]C-aminopyrine content in another manner than H[sub 2]-receptor antagonists. No effects were obtained by atropine or lidocaine, indicating that the elimination of [sup 14]C-amionopyrine is not an inticholinergic effect or due to membrane effects as exerted by local anesthetics. Stimulation of glands by further addition of histamine did not significantly stimulate the uptake of [sup 14]C-aminopyrine in the glands, whereas stimulation with db-cAMP produced an increase that was most pronounced when low concentrations of hydroxyzine had been used. It is suggested that H[sub 1]-receptor antagonists do not inhibit stimulation of acid production in the secretory canaliculi. They may, however, interfere with a mechanism preventing acid from leaving the parietal cell. Such a mechanism may contribute to the delay in appearance of acid in the gastric lumen after stimulation of gastric acid production. 37 refs., 7 figs.

  7. Effects of betahistine at histamine H3 receptors: mixed inverse agonism/agonism in vitro and partial inverse agonism in vivo.

    Science.gov (United States)

    Gbahou, F; Davenas, E; Morisset, S; Arrang, J-M

    2010-09-01

    We previously suggested that therapeutic effects of betahistine in vestibular disorders result from its antagonist properties at histamine H(3) receptors (H(3)Rs). However, H(3)Rs exhibit constitutive activity, and most H(3)R antagonists act as inverse agonists. Here, we have investigated the effects of betahistine at recombinant H(3)R isoforms. On inhibition of cAMP formation and [(3)H]arachidonic acid release, betahistine behaved as a nanomolar inverse agonist and a micromolar agonist. Both effects were suppressed by pertussis toxin, were found at all isoforms tested, and were not detected in mock cells, confirming interactions at H(3)Rs. The inverse agonist potency of betahistine and its affinity on [(125)I]iodoproxyfan binding were similar in rat and human. We then investigated the effects of betahistine on histamine neuron activity by measuring tele-methylhistamine (t-MeHA) levels in the brains of mice. Its acute intraperitoneal administration increased t-MeHA levels with an ED(50) of 0.4 mg/kg, indicating inverse agonism. At higher doses, t-MeHA levels gradually returned to basal levels, a profile probably resulting from agonism. After acute oral administration, betahistine increased t-MeHA levels with an ED(50) of 2 mg/kg, a rightward shift probably caused by almost complete first-pass metabolism. In each case, the maximal effect of betahistine was lower than that of ciproxifan, indicating partial inverse agonism. After an oral 8-day treatment, the only effective dose of betahistine was 30 mg/kg, indicating that a tolerance had developed. These data strongly suggest that therapeutic effects of betahistine result from an enhancement of histamine neuron activity induced by inverse agonism at H(3) autoreceptors.

  8. Influence of the novel histamine H₃ receptor antagonist ST1283 on voluntary alcohol consumption and ethanol-induced place preference in mice.

    Science.gov (United States)

    Bahi, Amine; Sadek, Bassem; Schwed, Stephan J; Walter, Miriam; Stark, Holger

    2013-07-01

    Growing evidence supports a role for the central histaminergic system to have a modulatory influence on drug addiction in general and alcohol-use disorders in particular through histamine H3 receptors (H3R). In the present study, the effects of systemic injection of the newly synthesized H3R antagonist ST1283 on ethanol (EtOH) voluntary intake and EtOH-conditioned reward in mice have been investigated. Oral EtOH, saccharin, and quinine intake was assessed in a two-bottle choice paradigm using escalating concentrations of alcohol or tastant solutions. EtOH-induced place preference (CPP), EtOH-induced locomotor activity, and blood ethanol concentration (BEC) were also measured. Following administration of the H3R antagonist (2.5, 5, and 10 mg/kg, i.p.), there was a significant dose-dependent decrease in alcohol consumption and preference. Importantly, vehicle- and ST1283 (5 mg/kg)-treated mice showed similar consumption and preference to increasing concentration of both sweet and bitter tastes. More interestingly, systemic administration of ST1283 inhibited EtOH-CPP and EtOH-enhanced locomotion. This inhibition was blocked when mice were pretreated with the selective H3R agonist R-(alpha)-methyl-histamine (10 mg/kg). Finally, vehicle- and ST1283-treated mice had similar BECs. Our results show that ST1283 may decrease voluntary EtOH consumption and EtOH-CPP by altering its reinforcing effects, suggesting a novel role for histamine signaling in regulation of alcoholism. Lastly, the results add to the growing literature on H3R modulation in the pharmacotherapy of EtOH addiction.

  9. Determination of receptor occupancy in the presence of mass dose: [(11)C]GSK189254 PET imaging of histamine H3 receptor occupancy by PF-03654746.

    Science.gov (United States)

    Gallezot, Jean-Dominique; Planeta, Beata; Nabulsi, Nabeel; Palumbo, Donna; Li, Xiaoxi; Liu, Jing; Rowinski, Carolyn; Chidsey, Kristin; Labaree, David; Ropchan, Jim; Lin, Shu-Fei; Sawant-Basak, Aarti; McCarthy, Timothy J; Schmidt, Anne W; Huang, Yiyun; Carson, Richard E

    2017-03-01

    Measurements of drug occupancies using positron emission tomography (PET) can be biased if the radioligand concentration exceeds "tracer" levels. Negative bias would also arise in successive PET scans if clearance of the radioligand is slow, resulting in a carryover effect. We developed a method to (1) estimate the in vivo dissociation constant Kd of a radioligand from PET studies displaying a non-tracer carryover (NTCO) effect and (2) correct the NTCO bias in occupancy studies taking into account the plasma concentration of the radioligand and its in vivo Kd. This method was applied in a study of healthy human subjects with the histamine H3 receptor radioligand [(11)C]GSK189254 to measure the PK-occupancy relationship of the H3 antagonist PF-03654746. From three test/retest studies, [(11)C]GSK189254 Kd was estimated to be 9.5 ± 5.9 pM. Oral administration of 0.1 to 4 mg of PF-03654746 resulted in occupancy estimates of 71%-97% and 30%-93% at 3 and 24 h post-drug, respectively. NTCO correction adjusted the occupancy estimates by 0%-15%. Analysis of the relationship between corrected occupancies and PF-03654746 plasma levels indicated that PF-03654746 can fully occupy H3 binding sites ( ROmax = 100%), and its IC50 was estimated to be 0.144 ± 0.010 ng/mL. The uncorrected IC50 was 26% higher.

  10. GPCRDB: an information system for G protein-coupled receptors

    NARCIS (Netherlands)

    Isberg, V.; Vroling, B.; Kant, R.; Li, K.; Vriend, G.; Gloriam, D.

    2014-01-01

    For the past 20 years, the GPCRDB (G protein-coupled receptors database; http://www.gpcr.org/7tm/) has been a 'one-stop shop' for G protein-coupled receptor (GPCR)-related data. The GPCRDB contains experimental data on sequences, ligand-binding constants, mutations and oligomers, as well as many

  11. The G protein-coupled receptor, class C, group 6, subtype A (GPRC6A) receptor

    DEFF Research Database (Denmark)

    Clemmensen, C; Smajilovic, S; Wellendorph, P

    2014-01-01

    GPRC6A (G protein-coupled receptor, class C, group 6, subtype A) is a class C G protein-coupled receptor, that has been cloned from human, mouse and rat. Several groups have shown that the receptor is activated by a range of basic and small aliphatic L-α-amino acids of which L-arginine, L-lysine...

  12. Histamine H1 and H4 receptor expression on the ocular surface of patients with chronic allergic conjunctival diseases.

    Science.gov (United States)

    Inada, Noriko; Shoji, Jun; Shiraki, Yukiko; Aso, Hiroshi; Yamagami, Satoru

    2017-10-01

    This study investigated the histamine H1 and H4 receptors mRNA (H1R and H4R, respectively) expression on the ocular surface of patients with chronic forms of allergic conjunctival diseases to determine whether they can serve as biomarkers for allergic inflammation in the conjunctiva. We examined 19 patients with vernal or atopic keratoconjunctivitis (AKC/VKC group) and 15 healthy volunteers (control group). The AKC/VKC group was divided into active and stable stage subgroups. Specimens were obtained from the upper tarsal conjunctiva of each participant using a modified impression cytology method. H1R, H4R, and eotaxin-1, -2, and -3 mRNA (eotaxin-1, eotaxin-2, eotaxin-3, respectively) expression was determined by real-time RT-PCR. Immunohistochemical analysis for eosinophil cationic protein (ECP), eosinophil major basic protein (MBP), eotaxin-2, and histamine H4 receptor (H4R) were performed using conjunctival smears. The number of H4R-positive patients was higher in the active than the stable stage subgroup and control group, whereas no difference was observed for H1R. H1R levels were higher in the active than in the stable stage subgroup, while those of H4R were higher in the active stage subgroup than in the control group. H1R and H4R levels were correlated with eotaxin-2 level. In immunohistochemical analysis, H4R revealed their expression on eosinophils in conjunctival smears of patients with AKC/VKC. H4R is useful as biomarkers of allergic inflammation on ocular surfaces. Most notably, H4R expressed on eosinophils is useful as a biomarker of eosinophilic inflammation of the ocular surface. Copyright © 2017 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

  13. Persistent Histamine Excitation of Glutamatergic Preoptic Neurons

    Science.gov (United States)

    Tabarean, Iustin V.

    2012-01-01

    Thermoregulatory neurons of the median preoptic nucleus (MnPO) represent a target at which histamine modulates body temperature. The mechanism by which histamine excites a population of MnPO neurons is not known. In this study it was found that histamine activated a cationic inward current and increased the intracellular Ca2+ concentration, actions that had a transient component as well as a sustained one that lasted for tens of minutes after removal of the agonist. The sustained component was blocked by TRPC channel blockers. Single-cell reverse transcription-PCR analysis revealed expression of TRPC1, TRPC5 and TRPC7 subunits in neurons excited by histamine. These studies also established the presence of transcripts for the glutamatergic marker Vglut2 and for the H1 histamine receptor in neurons excited by histamine. Intracellular application of antibodies directed against cytoplasmic sites of the TRPC1 or TRPC5 channel subunits decreased the histamine-induced inward current. The persistent inward current and elevation in intracellular Ca2+ concentration could be reversed by activating the PKA pathway. This data reveal a novel mechanism by which histamine induces persistent excitation and sustained intracellular Ca2+ elevation in glutamatergic MnPO neurons. PMID:23082195

  14. Rupatadine: a new selective histamine H1 receptor and platelet-activating factor (PAF) antagonist. A review of pharmacological profile and clinical management of allergic rhinitis.

    Science.gov (United States)

    Izquierdo, Iñaki; Merlos, Manuel; García-Rafanell, Julián

    2003-06-01

    Rupatadine is a new agent for the management of diseases with allergic inflammatory conditions, such as seasonal and perennial rhinitis. The pharmacological profile of rupatadine offers particular benefits in terms of a strong antagonist activity towards both histamine H1 receptors and platelet-activating factor (PAF) receptors. Rupatadine has a rapid onset of action, and its long-lasting effect (>24 h) permits once-daily dosing. Rupatadine should not be used in combination with the cytochrome P450 inhibitors, such as erythromycin or ketoconazole, due to an increase in AUC and Cmax for rupatadine, although no clinically relevant adverse events have been reported. In addition, rupatadine, at the recommended dose of 10 mg, has been shown to be free of sedative effects and not to cause significant changes in the corrected QT interval in special populations, including the elderly, nor when coadministered with erythromycin or ketoconazole. Preclinical data have also shown that rupatadine and its main active metabolites did not interfere with cloned human HERG channel and did not affect in vitro isolated dog Purkinje fibers at concentrations at least 2000 times greater than those obtained with therapeutic doses in humans. Rupatadine is clinically effective in relieving symptoms in patients with seasonal and perennial allergic rhinitis. Newly published data on its efficacy and safety suggest that this compound may improve the nasal and non-nasal symptoms in comparison to other currently available second generation H1 receptor antihistamines. 2003 Prous Science. All rights reserved.

  15. Postsynaptic mechanisms underlying the excitatory action of histamine on medial vestibular nucleus neurons in rats

    Science.gov (United States)

    Zhang, Xiao-Yang; Yu, Lei; Zhuang, Qian-Xing; Peng, Shi-Yu; Zhu, Jing-Ning; Wang, Jian-Jun

    2013-01-01

    Background and Purpose Anti-histaminergic drugs have been widely used in the clinical treatment of vestibular disorders and most studies concentrate on their presynaptic actions. The present study investigated the postsynaptic effect of histamine on medial vestibular nucleus (MVN) neurons and the underlying mechanisms. Experimental Approach Histamine-induced postsynaptic actions on MVN neurons and the corresponding receptor and ionic mechanisms were detected by whole-cell patch-clamp recordings on rat brain slices. The distribution of postsynaptic histamine H1, H2 and H4 receptors was mapped by double and single immunostaining. Furthermore, the expression of mRNAs for H1, H2 and H4 receptors and for subtypes of Na+–Ca2+ exchangers (NCXs) and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels was assessed by quantitative real-time RT-PCR. Key Results A marked postsynaptic excitatory effect, co-mediated by histamine H1 and H2 receptors, was involved in the histamine-induced depolarization of MVN neurons. Postsynaptic H1 and H2 rather than H4 receptors were co-localized in the same MVN neurons. NCXs contributed to the inward current mediated by H1 receptors, whereas HCN channels were responsible for excitation induced by activation of H2 receptors. Moreover, NCX1 and NCX3 rather than NCX2, and HCN1 rather than HCN2-4 mRNAs, were abundantly expressed in MVN. Conclusion and Implications NCXs coupled to H1 receptors and HCN channels linked to H2 receptors co-mediate the strong postsynaptic excitatory action of histamine on MVN neurons. These results highlight an active role of postsynaptic mechanisms in the modulation by central histaminergic systems of vestibular functions and suggest potential targets for clinical treatment of vestibular disorders. Linked Articles This article is part of a themed issue on Histamine Pharmacology Update. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2013.170.issue-1 PMID:23713466

  16. Proton pump inhibitor use and fracture risk - effect modification by histamine H1 receptor blockade. Observational case-control study using National Prescription Data.

    Science.gov (United States)

    Abrahamsen, Bo; Vestergaard, Peter

    2013-11-01

    It remains unknown why proton pump inhibitor (PPI) use may be associated with risk of osteoporotic fractures; evidence of direct effects on calcium absorption or on the osteoclast in humans is weak or absent. However, the ensuing increased gastrin levels may cause histamine production through hypertrophy of gastric enterochromaffin like cells, which could lead to bone loss. We speculated that H1 receptor antagonists (H1RA) used for allergies would then reduce the effect of PPI on bone. We therefore conducted a register-based case-control study comprising 124,655 patients with hospital treated fractures, who were matched 3:1 with non fracture control subjects of the same age and gender. Use of prescription medications was retrieved from the National Prescription Database and data was analyzed using conditional logistic regression analysis. We observed a significant interaction between PPI and H1RA use on fracture risk in general (adjusted OR 0.92, 95% CI 0.87-0.98) though not on hip fracture risk (adjusted OR 0.99, 95% CI 0.85-1.16). There was a significant modification of the interaction by age (pfracture categories). As previously shown, fracture risk was higher in PPI users both for fractures in general and for hip fractures. Irrespective of PPI use, H1RA users had lower risk of hip fractures than non-users (adjusted OR 0.86, 95% CI 0.79-0.93). This short report suggests that the effects of PPI on bone could be driven by in part by increased histamine release as the increased fracture risk can be modified by H1RA. © 2013.

  17. Histamine H4 receptor agonist-induced relief from painful peripheral neuropathy is mediated by inhibition of spinal neuroinflammation and oxidative stress.

    Science.gov (United States)

    Sanna, Maria Domenica; Lucarini, Laura; Durante, Mariaconcetta; Ghelardini, Carla; Masini, Emanuela; Galeotti, Nicoletta

    2017-01-01

    Neuropathic pain is under-treated, with a detrimental effect on quality of life, partly because of low treatment efficacy, but also because pathophysiological mechanisms are not fully elucidated. To clarify the pathobiology of neuropathic pain, we studied the contribution of neuroinflammation and oxidative stress in a model of peripheral neuropathy. We also assessed an innovative treatment for neuropathic pain by investigating the effects of histamine H4 receptor ligands in this model. A peripheral mononeuropathy was induced in mice, by spared nerve injury (SNI). Neuroinflammation and oxidative stress parameters were evaluated by spectrophotometry. The mechanical (von Frey test) and thermal (plantar test) nociceptive thresholds were evaluated. SNI mice showed increased expression of the pro-inflammatory cytokines IL-1ß and TNF-α, decreased antioxidant enzyme Mn-containing SOD (MnSOD), increased levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), an indicator of oxidative DNA damage, and of PARP, nuclear enzyme activated upon DNA damage. Intrathecal administration of VUF 8430 (H4 receptor agonist) reversed the mechanical and thermal allodynia and was associated with decreased expression of IL-1ß, TNF-α, 8-OHdG and PARP and with restoration of MnSOD activity in the spinal cord and sciatic nerve. These effects were prevented by JNJ 10191584 (H4 receptor antagonist). In the SNI mouse model of neuropathic pain, neuronal H4 receptor stimulation counteracts hyperalgesia and reduces neuroinflammation and oxidative stress in the spinal cord and sciatic nerve. Targeting both oxidative stress and pro-neuroinflammatory pathways through H4 receptor-mediated mechanisms could have promising therapeutic potential for neuropathic pain management. © 2016 The British Pharmacological Society.

  18. Effects of S 38093, an antagonist/inverse agonist of histamine H3 receptors, in models of neuropathic pain in rats.

    Science.gov (United States)

    Chaumette, T; Chapuy, E; Berrocoso, E; Llorca-Torralba, M; Bravo, L; Mico, J A; Chalus, M; Eschalier, A; Ardid, D; Marchand, F; Sors, A

    2018-01-01

    Histamine H3 receptors are mainly expressed on CNS neurons, particularly along the nociceptive pathways. The potential involvement of these receptors in pain processing has been suggested using H3 receptor inverse agonists. The antinociceptive effect of S 38093, a novel inverse agonist of H3 receptors, has been evaluated in several neuropathic pain models in rat and compared with those of gabapentin and pregabalin. While S 38093 did not change vocalization thresholds to paw pressure in healthy rats, it exhibited a significant antihyperalgesic effect in the Streptozocin-induced diabetic (STZ) neuropathy model after acute and chronic administration and, in the chronic constriction injury (CCI) model only after chronic administration, submitted to the paw-pressure test. Acute S 38093 administration at all doses tested displayed a significant cold antiallodynic effect in a model of acute or repeated administration of oxaliplatin-induced neuropathy submitted to cold tail immersion, cold allodynia being the main side effect of oxaliplatin in patients. The effect of S 38093 increased following chronic administration (i.e. twice a day during 5 days) in the CCI and STZ models except in the oxaliplatin models where its effect was already maximal from the first administration The kinetics and size of effect of S 38093 were similar to gabapentin and/or pregabalin. Finally, the antinociceptive effect of S 38093 could be partially mediated by α2 adrenoreceptors desensitization in the locus coeruleus. These results highlight the interest of S 38093 to relieve neuropathic pain and warrant clinical trials especially in chemotherapeutic agent-induced neuropathic pain. S 38093, a new H3 antagonist/inverse agonist, displays antiallodynic and antihyperalgesic effect in neuropathic pain, especially in oxaliplatin-induced neuropathy after chronic administration. This effect of S 38093 in neuropathic pain could be partly mediated by α2 receptors desensitization in the locus coeruleus

  19. Time-dependent histamine release from stored human blood products

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen; Edvardsen, L; Vangsgaard, K

    1996-01-01

    Perioperative transfusion of whole blood has been shown to amplify trauma-induced immunosuppression, which could be attenuated by perioperative administration of histamine2 receptor antagonists. Supernatants from different blood products were, therefore, analysed for histamine content during...... storage. Whole blood (six units), plasma-reduced whole blood (six units), and plasma- and buffy coat-reduced (saline-adenine-glucose-mannitol) (SAGM) blood (six units) from unpaid healthy donors were stored in the blood bank for 35 days at 4 degrees C. Plasma histamine and total cell-bound histamine...... content at donation, and histamine concentration in samples drawn from the units on days 0, 2, 5, 9, 14, 21, 28 and 35 were analysed with an enzyme-linked immunosorbent assay. Median plasma histamine concentration was 4.8 (range 1.9-14.3) nmol/l (n = 18). Median total cell-bound histamine content was 417...

  20. Vascular Effects of Histamine

    African Journals Online (AJOL)

    olayemitoyin

    Ackad and Brody, 1975). Also, coronary arteries of some patients with coronary artery disease have been reported to be hyperresponsive to histamine and to contain significantly higher concentrations of histamine (Kalsner and Richards, 1984). Mast cells present in post capillary venules also secrete histamine which induce ...

  1. Transcriptional and Functional Characterization of the G Protein-Coupled Receptor Repertoire of Gastric Somatostatin Cells

    DEFF Research Database (Denmark)

    Egerod, Kristoffer L; Engelstoft, Maja S; Lund, Mari L

    2015-01-01

    In the stomach, somatostatin (SST) acts as a general paracrine negative regulator of exocrine secretion of gastric acid and pepsinogen and endocrine secretion of gastrin, ghrelin, and histamine. Using reporter mice expressing red fluorescent protein (RFP) under control of the SST promotor, we have...... expressed and/or enriched. 1) The metabolite receptors calcium-sensing receptor and free fatty acid receptor 4 (GPR120) functioned as positive and negative regulators, respectively. 2) Among the neurotransmitter receptors, adrenergic receptors α1a, α2a, α2b, and β1 were all highly expressed...

  2. New factors influencing G protein coupled receptors' system functions

    African Journals Online (AJOL)

    New factors such as the G protein coupled receptor (GPCR) surrounding's chemical environment, cell membrane constituents, the existent gap junction, endogenous receptor affinity status and animal species have been shown to influence the GPCR physiology and variations of those factors can modify the functions of the ...

  3. Immunochemical cross-reactivity between albumin and solid-phase adsorbed histamine

    DEFF Research Database (Denmark)

    Poulsen, L K; Nolte, H; Søndergaard, I

    1990-01-01

    For production of an antibody against histamine, this was coupled to human serum albumin (HSA) and used for immunization of rabbits. To test the antiserum, an immunoradiometric assay was developed comprising solid-phase bound histamine, antisera and radiolabelled protein A. Titration and inhibition...... experiments revealed that histamine adsorbed onto a solid-phase could bind the antiserum. However, neither free histamine nor histamine coupled to unrelated carriers could inhibit the binding of antiserum to the solid-phase histamine. Cross-reactivity was demonstrated between HSA and solid-phase bound...

  4. Antihistamines suppress upregulation of histidine decarboxylase gene expression with potencies different from their binding affinities for histamine H1 receptor in toluene 2,4-diisocyanate-sensitized rats.

    Science.gov (United States)

    Mizuguchi, Hiroyuki; Das, Asish K; Maeyama, Kazutaka; Dev, Shrabanti; Shahriar, Masum; Kitamura, Yoshiaki; Takeda, Noriaki; Fukui, Hiroyuki

    2016-04-01

    Antihistamines inhibit histamine signaling by blocking histamine H1 receptor (H1R) or suppressing H1R signaling as inverse agonists. The H1R gene is upregulated in patients with pollinosis, and its expression level is correlated with the severity of nasal symptoms. Here, we show that antihistamine suppressed upregulation of histidine decarboxylase (HDC) mRNA expression in patients with pollinosis, and its expression level was correlated with that of H1R mRNA. Certain antihistamines, including mepyramine and diphenhydramine, suppress toluene-2,4-diisocyanate (TDI)-induced upregulation of HDC gene expression and increase HDC activity in TDI-sensitized rats. However, d-chlorpheniramine did not demonstrate any effect. The potencies of antihistamine suppressive effects on HDC mRNA elevation were different from their H1R receptor binding affinities. In TDI-sensitized rats, the potencies of antihistamine inhibitory effects on sneezing in the early phase were related to H1R binding. In contrast, the potencies of their inhibitory effects on sneezing in the late phase were correlated with those of suppressive effects on HDC mRNA elevation. Data suggest that in addition to the antihistaminic and inverse agonistic activities, certain antihistamines possess additional properties unrelated to receptor binding and alleviate nasal symptoms in the late phase by inhibiting synthesis and release of histamine by suppressing HDC gene transcription. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  5. Histamine facilitates GABAergic transmission in the rat entorhinal cortex: Roles of H1 and H2 receptors, Na+ -permeable cation channels, and inward rectifier K+ channels.

    Science.gov (United States)

    Cilz, Nicholas I; Lei, Saobo

    2017-05-01

    In the brain, histamine (HA) serves as a neuromodulator and a neurotransmitter released from the tuberomammillary nucleus (TMN). HA is involved in wakefulness, thermoregulation, energy homeostasis, nociception, and learning and memory. The medial entorhinal cortex (MEC) receives inputs from the TMN and expresses HA receptors (H1 , H2 , and H3 ). We investigated the effects of HA on GABAergic transmission in the MEC and found that HA significantly increased the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) with an EC50 of 1.3 µM, but failed to significantly alter sIPSC amplitude. HA-induced increases in sIPSC frequency were sensitive to tetrodotoxin (TTX), required extracellular Ca2+ , and persisted when GDP-β-S, a G-protein inactivator, was applied postsynaptically via the recording pipettes, indicating that HA increased GABA release by facilitating the excitability of GABAergic interneurons in the MEC. Recordings from local MEC interneurons revealed that HA significantly increased their excitability as determined by membrane depolarization, generation of an inward current at -65 mV, and augmentation of action potential firing frequency. Both H1 and H2 receptors were involved in HA-induced increases in sIPSCs and interneuron excitability. Immunohistochemical staining showed that both H1 and H2 receptors are expressed on GABAergic interneurons in the MEC. HA-induced depolarization of interneurons involved a mixed ionic mechanism including activation of a Na+ -permeable cation channel and inhibition of a cesium-sensitive inward rectifier K+ channel, although HA also inhibited the delayed rectifier K+ channels. Our results may provide a cellular mechanism, at least partially, to explain the roles of HA in the brain. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  6. Presynaptic G Protein-Coupled Receptors: Gatekeepers of Addiction?

    Directory of Open Access Journals (Sweden)

    Kari A Johnson

    2016-11-01

    Full Text Available Drug abuse and addiction cause widespread social and public health problems, and the neurobiology underlying drug actions and drug use and abuse is an area of intensive research. Drugs of abuse alter synaptic transmission, and these actions contribute to acute intoxication as well as the chronic effects of abused substances. Transmission at most mammalian synapses involves neurotransmitter activation of two receptor subtypes, ligand-gated ion channels that mediate fast synaptic responses, and G protein-coupled receptors (GPCRs that have slower neuromodulatory actions. The GPCRs represent a large proportion of neurotransmitter receptors involved in almost all facets of nervous system function. In addition, these receptors are targets for many pharmacotherapeutic agents. Drugs of abuse directly or indirectly affect neuromodulation mediated by GPCRs, with important consequences for intoxication, drug taking and responses to prolonged drug exposure, withdrawal and addiction. Among the GPCRs are several subtypes involved in presynaptic inhibition, most of which are coupled to the Gi/o class of G protein. There is increasing evidence that these presynaptic Gi/o-coupled GPCRs have important roles in the actions of drugs of abuse, as well as behaviors related to these drugs. This topic will be reviewed, with particular emphasis on receptors for three neurotransmitters, dopamine (D1- and D2-like receptors, endocannabinoids (CB1 receptors and glutamate (group II metabotropic glutamate (mGlu receptors. The focus is on recent evidence from laboratory animal models (and some evidence in humans implicating these receptors in the acute and chronic effects of numerous abused drugs, as well as in the control of drug seeking and taking. The ability of drugs targeting these receptors to modify drug seeking behavior has raised the possibility of using compounds targeting these receptors for addiction pharmacotherapy. This topic is also discussed, with emphasis on

  7. PPI versus Histamine H2 Receptor Antagonists for Prevention of Upper Gastrointestinal Injury Associated with Low-Dose Aspirin: Systematic Review and Meta-analysis.

    Directory of Open Access Journals (Sweden)

    Chen Mo

    Full Text Available This study compared proton pump inhibitors (PPIs and histamine H2 receptor antagonists (H2RAs for prevention of low-dose aspirin (LDA-related gastrointestinal (GI erosion, ulcer and bleeding. Electronic databases including PubMed, Embase, Cochrane Central Register of Controlled Trials, Chinese National Knowledge Infrastructure, Chinese Biomedical Literature Database, and WanFang Data were searched from the date of their establishment to December 31, 2013. Randomized controlled trials comparing PPIs and H2RAs for prevention of GI injury associated with low-dose aspirin (LDA were collected. Two reviewers independently abstracted studies and patient characteristics and appraised study quality using the Cochrane risk-of-bias tool. Meta-analysis was performed using RevMan 5.1 software. We included nine RCTs involving 1047 patients. The meta-analysis showed that PPIs were superior to H2RAs for prevention of LDA-associated GI erosion/ulcer [odds ratio (OR=0.28, 95% confidence interval (CI: 0.16-0.50] and bleeding (OR=0.28, 95% CI: 0.14-0.59. In conclusion, PPIs were superior to H2RAs for prevention of LDA-related GI erosion/ulcer and bleeding. Higher quality, large, multicenter RCTs are needed to demonstrate the preventive effect of the two acid-suppressive drugs.

  8. PPI versus Histamine H2 Receptor Antagonists for Prevention of Upper Gastrointestinal Injury Associated with Low-Dose Aspirin: Systematic Review and Meta-analysis.

    Science.gov (United States)

    Mo, Chen; Sun, Gang; Wang, Yan-Zhi; Lu, Ming-Liang; Yang, Yun-Sheng

    2015-01-01

    This study compared proton pump inhibitors (PPIs) and histamine H2 receptor antagonists (H2RAs) for prevention of low-dose aspirin (LDA)-related gastrointestinal (GI) erosion, ulcer and bleeding. Electronic databases including PubMed, Embase, Cochrane Central Register of Controlled Trials, Chinese National Knowledge Infrastructure, Chinese Biomedical Literature Database, and WanFang Data were searched from the date of their establishment to December 31, 2013. Randomized controlled trials comparing PPIs and H2RAs for prevention of GI injury associated with low-dose aspirin (LDA) were collected. Two reviewers independently abstracted studies and patient characteristics and appraised study quality using the Cochrane risk-of-bias tool. Meta-analysis was performed using RevMan 5.1 software. We included nine RCTs involving 1047 patients. The meta-analysis showed that PPIs were superior to H2RAs for prevention of LDA-associated GI erosion/ulcer [odds ratio (OR=0.28, 95% confidence interval (CI): 0.16-0.50] and bleeding (OR=0.28, 95% CI: 0.14-0.59). In conclusion, PPIs were superior to H2RAs for prevention of LDA-related GI erosion/ulcer and bleeding. Higher quality, large, multicenter RCTs are needed to demonstrate the preventive effect of the two acid-suppressive drugs.

  9. Preseasonal prophylactic treatment with antihistamines suppresses nasal symptoms and expression of histamine H₁ receptor mRNA in the nasal mucosa of patients with pollinosis.

    Science.gov (United States)

    Mizuguchi, H; Kitamura, Y; Kondo, Y; Kuroda, W; Yoshida, H; Miyamoto, Y; Hattori, M; Fukui, H; Takeda, N

    2010-12-01

    Administration of antihistamines 2-4 weeks before the pollen season showed a greater inhibitory effect on nasal allergy symptoms in patients with seasonal allergic rhinitis. However, the mechanism of slow-onset effects of preseasonal treatment with antihistamines remains unclear. Here, we investigated the effect of preseasonal prophylactic treatment with antihistamines on nasal symptoms and the expression of histamine H₁ receptor (H1R) mRNA of the nasal mucosa in patients with cedar pollen pollinosis. During the peak pollen period, the expression of H1R mRNA in the nasal mucosa and the scores of sneezing and watery rhinorrhea in patients receiving preseasonal prophylactic treatment with antihistamines were significantly suppressed in comparison with those in the patients without treatment. Moreover, there was a significant correlation between the nasal symptoms and the expression of H1R mRNA in both patients with or without preseasonal prophylactic treatment. These findings suggest that preseasonal prophylactic treatment with antihistamines is more effective than on-seasonal administration to patients with pollinosis in reducing nasal symptoms during the peak pollen period by suppressing H1R gene expression in the nasal mucosa. Copyright 2010 Prous Science, S.A.U. or its licensors. All rights reserved.

  10. Real-Time G-Protein-Coupled Receptor Imaging to Understand and Quantify Receptor Dynamics

    Directory of Open Access Journals (Sweden)

    María S. Aymerich

    2011-01-01

    Full Text Available Understanding the trafficking of G-protein-coupled receptors (GPCRs and their regulation by agonists and antagonists is fundamental to develop more effective drugs. Optical methods using fluorescent-tagged receptors and spinning disk confocal microscopy are useful tools to investigate membrane receptor dynamics in living cells. The aim of this study was to develop a method to characterize receptor dynamics using this system which offers the advantage of very fast image acquisition with minimal cell perturbation. However, in short-term assays photobleaching was still a problem. Thus, we developed a procedure to perform a photobleaching-corrected image analysis. A study of short-term dynamics of the long isoform of the dopamine type 2 receptor revealed an agonist-induced increase in the mobile fraction of receptors with a rate of movement of 0.08 μm/s For long-term assays, the ratio between the relative fluorescence intensity at the cell surface versus that in the intracellular compartment indicated that receptor internalization only occurred in cells co-expressing G protein-coupled receptor kinase 2. These results indicate that the lateral movement of receptors and receptor internalization are not directly coupled. Thus, we believe that live imaging of GPCRs using spinning disk confocal image analysis constitutes a powerful tool to study of receptor dynamics.

  11. The lactate receptor, G-protein-coupled receptor 81/hydroxycarboxylic acid receptor 1

    DEFF Research Database (Denmark)

    Morland, Cecilie; Lauritzen, Knut Huso; Puchades, Maja

    2015-01-01

    , and schizophrenia and in the deposition of phosphorylated tau protein in Alzheimer's disease. HCAR1 could serve to ameliorate these conditions and might also act through downstream mechanisms other than cAMP. Lactate exits cells through monocarboxylate transporters in an equilibrating manner and through astrocyte......We have proposed that lactate is a “volume transmitter” in the brain and underpinned this by showing that the lactate receptor, G-protein-coupled receptor 81 (GPR81, also known as HCA1 or HCAR1), which promotes lipid storage in adipocytes, is also active in the mammalian brain. This includes...... the cerebral neocortex and the hippocampus, where it can be stimulated by physiological concentrations of lactate and by the HCAR1 agonist 3,5-dihydroxybenzoate to reduce cAMP levels. Cerebral HCAR1 is concentrated on the postsynaptic membranes of excitatory synapses and also is enriched at the blood...

  12. Can human allergy drug fexofenadine, an antagonist of histamine (H1) receptor, be used to treat dog and cat? Homology modeling, docking and molecular dynamic Simulation of three H1 receptors in complex with fexofenadine.

    Science.gov (United States)

    Sader, Safaa; Cai, Jun; Muller, Anna C G; Wu, Chun

    2017-08-01

    Fexofenadine, a potent antagonist to human histamine 1 (H1) receptor, is a non-sedative third generation antihistamine that is widely used to treat various human allergic conditions such as allergic rhinitis, conjunctivitis and atopic dermatitis. Encouragingly, it's been successfully used to treat canine atopic dermatitis, this supports the notion that it might have a great potential for treating other canine allergic conditions and other mammal pets such as dog. Regrettably, while there is a myriad of studies conducted on the interactions of antihistamines with human H1 receptor, the similar studies on non-human pet H1 are considerably scarce. The published studies using the first and second generation antihistamines drugs have shown that the antihistamine response is varied and unpredictable. Thus, to probe its efficacy on pet, the homology models of dog and cat H1 receptors were built based on the crystal structure of human H1 receptor bound to antagonist doxepin (PDB 3RZE) and fexofenadine was subsequently docked to human, dog and cat H1 receptors. The docked complexes are then subjected to 1000ns molecular dynamics (MD) simulations with explicit membrane. Our calculated MM/GBSA binding energies indicated that fexofenadine binds comparably to the three receptors; and our MD data also showed the binding poses, structural and dynamic features among three receptors are very similar. Therefore, our data supported the application of fexofenadine to the H1 related allergic conditions of dog and cat. Nonetheless, subtle systemic differences among human, dog and cat H1 receptors were also identified. Clearly, there is still a space to develop a more selective, potent and safe antihistamine alternatives such as Fexofenadine for dog or cat based on these differences. Our computation approach might provide a fast and economic way to predict if human antihistamine drugs can also be safely and efficaciously administered to animals. Copyright © 2017 Elsevier Inc. All rights

  13. Luciferase reporter gene assay on human, murine and rat histamine H4 receptor orthologs: correlations and discrepancies between distal and proximal readouts.

    Directory of Open Access Journals (Sweden)

    Uwe Nordemann

    Full Text Available The investigation of the (pathophysiological role of the histamine H4 receptor (H4R and its validation as a possible drug target in translational animal models are compromised by distinct species-dependent discrepancies regarding potencies and receptor subtype selectivities of the pharmacological tools. Such differences were extremely pronounced in case of proximal readouts, e. g. [(32P]GTPase or [(35S]GTPγS binding assays. To improve the predictability of in vitro investigations, the aim of this study was to establish a reporter gene assay for human, murine and rat H4Rs, using bioluminescence as a more distal readout. For this purpose a cAMP responsive element (CRE controlled luciferase reporter gene assay was established in HEK293T cells, stably expressing the human (h, the mouse (m or the rat (r H4R. The potencies and efficacies of 23 selected ligands (agonists, inverse agonists and antagonists were determined and compared with the results obtained from proximal readouts. The potencies of the examined ligands at the human H4R were consistent with reported data from [(32P]GTPase or [(35S]GTPγS binding assays, despite a tendency toward increased intrinsic efficacies of partial agonists. The differences in potencies of individual agonists at the three H4R orthologs were generally less pronounced compared to more proximal readouts. In conclusion, the established reporter gene assay is highly sensitive and reliable. Regarding discrepancies compared to data from functional assays such as [(32P]GTPase and [(35S]GTPγS binding, the readout may reflect multifactorial causes downstream from G-protein activation, e.g. activation/amplification of or cross-talk between different signaling pathways.

  14. Using electrophysiology and in silico three-dimensional modeling to reduce human Ether-à-go-go related gene K(+) channel inhibition in a histamine H3 receptor antagonist program.

    Science.gov (United States)

    Davenport, Adam J; Möller, Clemens; Heifetz, Alexander; Mazanetz, Michael P; Law, Richard J; Ebneth, Andreas; Gemkow, Mark J

    2010-12-01

    The histamine H3 receptor (H3R) plays a regulatory role in the presynaptic release of histamine and several other neurotransmitters, and thus, it is an attractive target for central nervous system indications including cognitive disorders, narcolepsy, attention-deficit hyperactivity disorder, and pain. The development of H3R antagonists was complicated by the similarities between the pharmacophores of H3R and human Ether-à-go-go related gene (hERG) channel blockers, a fact that probably prevented promising compounds from being progressed into the clinic. Using a three-dimensional in silico modeling approach complemented with automated and manual patch clamping, we were able to separate these two pharmacophores and to develop highly potent H3R antagonists with reduced risk of hERG liabilities from initial hit series with low selectivity identified in a high-throughput screening campaign.

  15. An overview of anti-allergic drug therapy and the histamine-1 ...

    African Journals Online (AJOL)

    Histamine is also secreted in the fundus of the stomach, where its function is to interact with histamine-2 (H2) receptors, and thereby stimulate the secretion of gastric acid by the stomach's parietal cells.1-3. Histamine is a particularly important mediator of the inflammatory process. This process, as a pathophysiological entity ...

  16. Are basophil histamine release and high affinity IgE receptor expression involved in asymptomatic skin sensitization?

    DEFF Research Database (Denmark)

    Jensen, Bettina Margrethe; Assing, K; Jensen, Lone Hummelshøj

    2006-01-01

    Immunoglobulin (Ig)E-sensitized persons with positive skin prick test, but no allergy symptoms, are classified as being asymptomatic skin sensitized (AS). The allergic type 1 disease is dependant on IgE binding to the high affinity IgE-receptor (FcepsilonRI) expressed on basophils and mast cells...

  17. The repertoire of trace amine G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Gloriam, David E.; Bjarnadóttir, Thóra K; Yan, Yi-Lin

    2005-01-01

    Trace amines, such as tyramine, beta-phenylethylamine, tryptamine, and octopamine, are present in trace levels in nervous systems and bind a specific family of G-protein-coupled receptors (GPCR), but the function or origin of this system is not well understood. We searched the genomes of several ...... ancestor of vertebrate TA-receptors arose before the split of the ray-finned and lobe-finned fishes. The evolutionary history of the TA-receptors is more complex than for most other GPCR families and here we suggest a mechanism by which they may have arisen....

  18. Biased signaling of G protein-coupled receptors - From a chemokine receptor CCR7 perspective

    DEFF Research Database (Denmark)

    Jørgensen, Astrid Sissel; Rosenkilde, Mette M; Hjortø, Gertrud M

    2018-01-01

    Chemokines (chemotactic cytokines) and their associated G protein-coupled receptors (GPCRs) work in a concerted manner to govern immune cell positioning in time and space. Promiscuity of both ligands and receptors, but also biased signaling within the chemokine system, adds to the complexity of how...

  19. Regulation of the Cardiovascular System by Histamine.

    Science.gov (United States)

    Hattori, Yuichi; Hattori, Kohshi; Matsuda, Naoyuki

    2017-01-01

    Histamine mediates a wide range of cellular responses, including allergic and inflammatory reactions, gastric acid secretion, and neurotransmission in the central nervous system. Histamine also exerts a series of actions upon the cardiovascular system but may not normally play a significant role in regulating cardiovascular function. During tissue injury, inflammation, and allergic responses, mast cells (or non-mast cells) within the tissues can release large amounts of histamine that leads to noticeable cardiovascular effects. Owing to intensive research during several decades, the distribution, function, and pathophysiological role of cardiovascular H1- and H2-receptors has become recognized adequately. Besides the recognized H1- and H2-receptor-mediated cardiovascular responses, novel roles of H3- and H4-receptors in cardiovascular physiology and pathophysiology have been identified over the last decade. In this review, we describe recent advances in our understanding of cardiovascular function and dysfunction mediated by histamine receptors, including H3- and H4-receptors, their potential mechanisms of action, and their pathological significance.

  20. A monoclonal antibody for G protein-coupled receptor crystallography

    DEFF Research Database (Denmark)

    Day, Peter W; Rasmussen, Søren Gøgsig Faarup; Parnot, Charles

    2007-01-01

    G protein-coupled receptors (GPCRs) constitute the largest family of signaling proteins in mammals, mediating responses to hormones, neurotransmitters, and senses of sight, smell and taste. Mechanistic insight into GPCR signal transduction is limited by a paucity of high-resolution structural...

  1. 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...

  2. Receptor Quaternary Organization Explains G Protein-Coupled Receptor Family Structure

    Directory of Open Access Journals (Sweden)

    James H. Felce

    2017-09-01

    Full Text Available The organization of Rhodopsin-family G protein-coupled receptors (GPCRs at the cell surface is controversial. Support both for and against the existence of dimers has been obtained in studies of mostly individual receptors. Here, we use a large-scale comparative study to examine the stoichiometric signatures of 60 receptors expressed by a single human cell line. Using bioluminescence resonance energy transfer- and single-molecule microscopy-based assays, we found that a relatively small fraction of Rhodopsin-family GPCRs behaved as dimers and that these receptors otherwise appear to be monomeric. Overall, the analysis predicted that fewer than 20% of ∼700 Rhodopsin-family receptors form dimers. The clustered distribution of the dimers in our sample and a striking correlation between receptor organization and GPCR family size that we also uncover each suggest that receptor stoichiometry might have profoundly influenced GPCR expansion and diversification.

  3. Pharmacokinetics, pharmacodynamics and safety of CEP-26401, a high-affinity histamine-3 receptor antagonist, following single and multiple dosing in healthy subjects.

    Science.gov (United States)

    Spiegelstein, Ofer; Stevens, Jasper; Van Gerven, Joop; Nathan, Pradeep J; Maynard, James P; Mayleben, David W; Hellriegel, Edward; Yang, Ronghua

    2016-10-01

    CEP-26401 is a novel orally active, brain-penetrant, high-affinity histamine H3 receptor (H3R) antagonist, with potential therapeutic utility in cognition enhancement. Two randomized, double-blind, placebo-controlled dose escalation studies with single (0.02 to 5 mg) or multiple administration (0.02 to 0.5 mg once daily) of CEP-26401 were conducted in healthy subjects. Plasma and urine samples were collected to investigate CEP-26401 pharmacokinetics. Pharmacodynamic endpoints included a subset of tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB) and nocturnal polysomnography. Population pharmacokinetic-pharmacodynamic modeling was conducted on one CANTAB and one polysomnography parameter of interest. CEP-26401 was slowly absorbed (median tmax range 3-6 hours) and the mean terminal elimination half-life ranged from 24-60 hours. Steady-state plasma concentrations were achieved within six days of dosing. CEP-26401 exhibits dose- and time-independent pharmacokinetics, and renal excretion is a major elimination pathway. CEP-26401 had a dose-dependent negative effect on sleep, with some positive effects on certain CANTAB cognitive parameters seen at lower concentrations. The derived three compartment population pharmacokinetic model, with first-order absorption and elimination, accurately described the available pharmacokinetic data. CEP-26401 was generally well tolerated up to 0.5 mg/day with most common treatment related adverse events being headache and insomnia. Further clinical studies are required to establish the potential of low-dose CEP-26401 in cognition enhancement. © The Author(s) 2016.

  4. Membrane cholesterol access into a G-protein-coupled receptor

    Science.gov (United States)

    Guixà-González, Ramon; Albasanz, José L.; Rodriguez-Espigares, Ismael; Pastor, Manuel; Sanz, Ferran; Martí-Solano, Maria; Manna, Moutusi; Martinez-Seara, Hector; Hildebrand, Peter W.; Martín, Mairena; Selent, Jana

    2017-02-01

    Cholesterol is a key component of cell membranes with a proven modulatory role on the function and ligand-binding properties of G-protein-coupled receptors (GPCRs). Crystal structures of prototypical GPCRs such as the adenosine A2A receptor (A2AR) have confirmed that cholesterol finds stable binding sites at the receptor surface suggesting an allosteric role of this lipid. Here we combine experimental and computational approaches to show that cholesterol can spontaneously enter the A2AR-binding pocket from the membrane milieu using the same portal gate previously suggested for opsin ligands. We confirm the presence of cholesterol inside the receptor by chemical modification of the A2AR interior in a biotinylation assay. Overall, we show that cholesterol's impact on A2AR-binding affinity goes beyond pure allosteric modulation and unveils a new interaction mode between cholesterol and the A2AR that could potentially apply to other GPCRs.

  5. Multifactorial Regulation of G Protein-Coupled Receptor Endocytosis

    Science.gov (United States)

    Zhang, Xiaohan; Kim, Kyeong-Man

    2017-01-01

    Endocytosis is a process by which cells absorb extracellular materials via the inward budding of vesicles formed from the plasma membrane. Receptor-mediated endocytosis is a highly selective process where receptors with specific binding sites for extracellular molecules internalize via vesicles. G protein-coupled receptors (GPCRs) are the largest single family of plasma-membrane receptors with more than 1000 family members. But the molecular mechanisms involved in the regulation of GPCRs are believed to be highly conserved. For example, receptor phosphorylation in collaboration with β-arrestins plays major roles in desensitization and endocytosis of most GPCRs. Nevertheless, a number of subsequent studies showed that GPCR regulation, such as that by endocytosis, occurs through various pathways with a multitude of cellular components and processes. This review focused on i) functional interactions between homologous and heterologous pathways, ii) methodologies applied for determining receptor endocytosis, iii) experimental tools to determine specific endocytic routes, iv) roles of small guanosine triphosphate-binding proteins in GPCR endocytosis, and v) role of post-translational modification of the receptors in endocytosis. PMID:28035080

  6. Applications of molecular replacement to G protein-coupled receptors

    Energy Technology Data Exchange (ETDEWEB)

    Kruse, Andrew C.; Manglik, Aashish; Kobilka, Brian K., E-mail: kobilka@stanford.edu [Stanford University, 279 Campus Drive, Stanford, CA 94305 (United States); Weis, William I., E-mail: kobilka@stanford.edu [Stanford University, 279 Campus Drive, Stanford, CA 94305 (United States); Stanford University, Fairchild Building, Stanford, CA 94305 (United States)

    2013-11-01

    The use of molecular replacement in solving the structures of G protein-coupled receptors is discussed, with specific examples being described in detail. G protein-coupled receptors (GPCRs) are a large class of integral membrane proteins involved in regulating virtually every aspect of human physiology. Despite their profound importance in human health and disease, structural information regarding GPCRs has been extremely limited until recently. With the advent of a variety of new biochemical and crystallographic techniques, the structural biology of GPCRs has advanced rapidly, offering key molecular insights into GPCR activation and signal transduction. To date, almost all GPCR structures have been solved using molecular-replacement techniques. Here, the unique aspects of molecular replacement as applied to individual GPCRs and to signaling complexes of these important proteins are discussed.

  7. Structural Studies of G Protein-Coupled Receptors.

    Science.gov (United States)

    Zhang, Dandan; Zhao, Qiang; Wu, Beili

    2015-10-01

    G protein-coupled receptors (GPCRs) constitute the largest and the most physiologically important membrane protein family that recognizes a variety of environmental stimuli, and are drug targets in the treatment of numerous diseases. Recent progress on GPCR structural studies shed light on molecular mechanisms of GPCR ligand recognition, activation and allosteric modulation, as well as structural basis of GPCR dimerization. In this review, we will discuss the structural features of GPCRs and structural insights of different aspects of GPCR biological functions.

  8. G-Protein Coupled Receptors Targeted by Analgesic Venom Peptides

    OpenAIRE

    James T. Daniel; Clark, Richard J.

    2017-01-01

    Chronic pain is a complex and debilitating condition associated with a large personal and socioeconomic burden. Current pharmacological approaches to treating chronic pain such as opioids, antidepressants and anticonvulsants exhibit limited efficacy in many patients and are associated with dose-limiting side effects that hinder their clinical use. Therefore, improved strategies for the pharmacological treatment of pathological pain are urgently needed. G-protein coupled receptors (GPCRs) are ...

  9. Histamine and the regulation of body weight

    DEFF Research Database (Denmark)

    Jørgensen, Emilie A; Knigge, Ulrich; Warberg, Jørgen

    2007-01-01

    Energy intake and expenditure is regulated by a complex interplay between peripheral and central factors. An exhaustive list of peptides and neurotransmitters taking part in this complex regulation of body weight exists. Among these is histamine, which acts as a central neurotransmitter. In the p......Energy intake and expenditure is regulated by a complex interplay between peripheral and central factors. An exhaustive list of peptides and neurotransmitters taking part in this complex regulation of body weight exists. Among these is histamine, which acts as a central neurotransmitter...... lipolysis. Based on the current evidence of the involvement of histamine in the regulation of body weight, the histaminergic system is an obvious target for the development of pharmacological agents to control obesity. At present, H(3) receptor antagonists that stimulate the histaminergic system may...

  10. Novel fused pyrrole heterocyclic ring systems as structure analogs of LE 300: Synthesis and pharmacological evaluation as serotonin 5-HT(2A), dopamine and histamine H(1) receptor ligands.

    Science.gov (United States)

    Rostom, Sherif A F

    2010-02-01

    LE 300 represents a structurally novel type of antagonists acting preferentially at the dopamine D(1)/D(5 )receptors and the serotonin 5-HT(2A )receptor. This compound consists of a ten-membered central azecine ring fused to an indole ring on one side and a benzene moiety on the other side. To estimate the importance of the indole and / or phenyl moieties in this highly active benz-indolo-azecine, both rings were removed and replaced with a 1H-pyrrole counterpart. Accordingly, some new analogs of LE 300 namely, pyrrolo[2,3-g]indolizine, pyrrolo[3,2-a]quinolizine rings and their corresponding dimethylpyrrolo[2,3-d]azonine, and dimethylpyrrolo[2,3-d]azecine were synthesized to be evaluated for their activity at the 5-HT(2A) and dopamine D(1), D(2L), D(4), D(5) receptors in relation to LE 300. In addition, their activity at the H(1)-histamine receptors was also determined. The results suggested that the rigid pyrrolo[2,3-g]indolizine 7 and pyrrolo[3,2-a]quinolizine 8 analogs lacked biological activity in the adopted three bioassays. However, their corresponding flexible pyrrolo[2,3-d]azonine 11 and pyrrolo[2,3-d]azecine 12 derivatives revealed weak partial agonistic activity and weak antagonistic potency at the serotonin 5-HT(2A )and histamine H(1 )receptors, respectively. Meanwhile, they showed no affinity to any of the four utilized dopamine receptors. Variation in ring size did not contribute to a significant influence on the three tested bioactivities. Removal of the hydrophobic moiety (phenyl ring) and replacement of the indole moiety with a 1H-pyrrole counterpart led to a dramatic alteration in the profile of activity of such azecine-type compounds.

  11. Toward fluorescent probes for G-protein-coupled receptors (GPCRs).

    Science.gov (United States)

    Ma, Zhao; Du, Lupei; Li, Minyong

    2014-10-23

    G-protein-coupled receptors (GPCRs), a superfamily of cell-surface receptors that are the targets of about 40% of prescription drugs on the market, can sense numerous critical extracellular signals. Recent breakthroughs in structural biology, especially in holo-form X-ray crystal structures, have contributed to our understanding of GPCR signaling. However, actions of GPCRs at the cellular and molecular level, interactions between GPCRs, and the role of protein dynamics in receptor activities still remain controversial. To overcome these dilemmas, fluorescent probes of GPCRs have been employed, which have advantages of in vivo safety and real-time monitoring. Various probes that depend on specific mechanisms and/or technologies have been used to study GPCRs. The present review focuses on surveying the design and applications of fluorescent probes for GPCRs that are derived from small molecules or using protein-labeling techniques, as well as discussing some design strategies for new probes.

  12. On histamine and appetites

    Directory of Open Access Journals (Sweden)

    Fernando eTorrealba

    2012-07-01

    Full Text Available Brain histamine may influence a variety of different behavioral and physiological functions, but its responsibility in waking up has casted a long shadow on other important functions of this neurotransmitter. Here we review evidence indicating a central role of brain histamine in motivation, emphasizing its differential involvement in the appetitive and consummatory phases of motivated behaviors. We discuss the inputs that control the histaminergic neurons of the tuberomamillary nucleus of the hypothalamus, which determine the distinct role of these neurons in appetitive behavior, sleep/wake cycles and in food anticipatory activity. We review evidence supporting a dysfunction of histamine neurons and its cortical input in certain forms of decreased motivation (apathy. We finally discuss the relationship between the histamine system and drug addiction as a dysfunction of motivation.

  13. Spinal histamine in attenuation of mechanical hypersensitivity in the spinal nerve ligation-induced model of experimental neuropathy.

    Science.gov (United States)

    Wei, Hong; Viisanen, Hanna; You, Hao-Jun; Pertovaara, Antti

    2016-02-05

    Here we studied whether and through which mechanisms spinal administration of histamine dihydrochloride (histamine) attenuates pain behavior in neuropathic animals. Experiments were performed in rats with spinal nerve ligation-induced neuropathy and a chronic intrathecal catheter for spinal drug delivery. Mechanical hypersensitivity was assessed with monofilaments while radiant heat was used for assessing nociception. Ongoing neuropathic pain and its attenuation by histamine was assessed using conditioned place-preference test. Following spinal administration, histamine at doses 0.1-10µg produced a dose-related mechanical antihypersensitivity effect. With prolonged treatment (twice daily 10µg for five days), the antihypersensitivity effect of spinal histamine was reduced. In place-preference test, neuropathic animals preferred the chamber paired with histamine (10µg). Histamine (10µg) failed to influence heat nociception in neuropathic animals or mechanically induced pain behavior in a group of healthy control rats. Histamine-induced mechanical antihypersensitivity effect was prevented by spinal pretreatment with zolantidine (histamine H2 receptor antagonist), prazosine (α1-adrenoceptor antagonist) and bicuculline (γ-aminobutyric acid subtype A, GABA(A), receptor antagonist), but not by pyrilamine (histamine H1 receptor antagonist), atipamezole (α2-adrenoceptor antagonist), or raclopride (dopamine D2 receptor antagonist). A-960656, a histamine H3 receptor antagonist alone that presumably increased endogenous histamine levels reduced hypersensitivity. Additionally, histamine prevented central (presumably postsynaptically-induced) facilitation of hypersensitivity induced by N-methyl-d-aspartate. The results indicate that spinal histamine at the dose range of 0.1-10µg selectively attenuates mechanical hypersensitivity and ongoing pain in neuropathy. The spinal histamine-induced antihypersensitivity effect involves histamine H2 and GABA(A) receptors and

  14. The role of histamine in opening blood-tumor barrier.

    Science.gov (United States)

    Wang, Zeng; Cai, Xin-Jun; Qin, Jing; Xie, Fa-Jun; Han, Na; Lu, Hong-Yang

    2016-05-24

    Blood-tumor barrier (BTB) reduce the permeability for drugs into tumor tissues. We found that histamine might serve as an essential regulator of BTB function. Further, we aim to determine the role of H2 receptor expression in BTB permeability, and elucidate the underlying mechanisms thereof. Transmission electron microscopy showed that histamine disrupted the integrity of tight junctions (TJ) and increased the number of pinosomes in the cytoplasm. Horseradish peroxidase (HRP) and trans-endothelial resistance detection (TEER) assays revealed that histamine could open BTB and this action was inhibited by cimetidine. Western blot and immunofluorescence assays showed that histamine decreased the expression of tight junction proteins zonula occluden-1(ZO-1), occludin, and claudin-5. Further, quantitative RT-PCR assay showed that the expression of H2 receptor could represent and predicted histamine-induced BTB permeability. In conclusion, histamine opened BTB by down-regulating the TJ-associated proteins. The levels of H2 receptor expression was correlated with the histamine-induced BTB permeability.

  15. Histaprodifens: synthesis, pharmacological in vitro evaluation, and molecular modeling of a new class of highly active and selective histamine H1-receptor agonists

    NARCIS (Netherlands)

    Elz, S.; Kramer, K.; Pertz, H.H.; Detert, M.; ter Laak, A.M.; Kuehne, R; Schunack, W.

    2000-01-01

    A new class of histamine analogues characterized by a 3,3-diphenylpropyl substituent at the 2-position of the imidazole nucleus has been prepared outgoing from 4,4-diphenylbutyronitrile (4b) via cyclization of the corresponding methyl imidate 5b with 2-oxo-4-phthalimido-1-butyl acetate or

  16. Proton pump inhibitor use and fracture risk - effect modification by histamine H1 receptor blockade. Observational case-control study using National Prescription Data

    DEFF Research Database (Denmark)

    Abrahamsen, Bo; Vestergaard, Peter

    2013-01-01

    It remains unknown why proton pump inhibitor (PPI) use may be associated with risk of osteoporotic fractures; evidence of direct effects on calcium absorption or on the osteoclast in humans is weak or absent. However, the ensuing increased gastrin levels may cause histamine production through...

  17. Effects of rupatadine, a new dual antagonist of histamine and platelet-activating factor receptors, on human cardiac kv1.5 channels.

    Science.gov (United States)

    Caballero, R; Valenzuela, C; Longobardo, M; Tamargo, J; Delpón, E

    1999-11-01

    1. The effects of rupatadine, a new dual antagonist of both histamine H1 and platelet-activating factor receptors, were studied on human cloned hKv1.5 channels expressed in Ltk- cells using the whole-cell patch-clamp technique. 2. Rupatadine produced a use- and concentration-dependent block of hKv1.5 channels (KD=2.4+/-0.7 micronM) and slowed the deactivation of the tail currents, thus inducing the 'crossover' phenomenon. 3. Rupatadine-induced block was voltage-dependent increasing in the voltage range for channel opening suggesting an open channel interaction. At potentials positive to +10 mV the blockade decreased with a shallow voltage-dependence. Moreover, rupatadine also modified the voltage-dependence of hKv1.5 channel activation, which exhibited two components, the midpoint of the steeper component averaging -25. 2+/-2.7 mV. 4. When the intracellular K+ concentration ([K+]i) was lowered to 25% the voltage-dependent unblock observed at positive potentials was suppressed and the activation curve in the presence of rupatadine did not exhibit two components even when the midpoint of the activation curve was shifted to more negative potentials (-30. 3+/-1.3 mV). 5. On channels mutated on the residue R485 (R485Y) which is located on the external entryway of the pore the rupatadine-induced block did not decrease at potentials positive to +10 mV. In contrast, on V512M channels rupatadine reproduced all the features of the blockade observed on wild type channels. 6. All these results suggest that rupatadine blocks hKv1.5 channels binding to an external and to an internal binding site but only at concentrations much higher than therapeutic plasma levels in man. Efflux of K+ promotes the unbinding from the external site. Furthermore, rupatadine binds to an internal site and dramatically modifies the voltage-dependence of channel opening.

  18. Structural organization of G-protein-coupled receptors

    Science.gov (United States)

    Lomize, Andrei L.; Pogozheva, Irina D.; Mosberg, Henry I.

    1999-07-01

    Atomic-resolution structures of the transmembrane 7-α-helical domains of 26 G-protein-coupled receptors (GPCRs) (including opsins, cationic amine, melatonin, purine, chemokine, opioid, and glycoprotein hormone receptors and two related proteins, retinochrome and Duffy erythrocyte antigen) were calculated by distance geometry using interhelical hydrogen bonds formed by various proteins from the family and collectively applied as distance constraints, as described previously [Pogozheva et al., Biophys. J., 70 (1997) 1963]. The main structural features of the calculated GPCR models are described and illustrated by examples. Some of the features reflect physical interactions that are responsible for the structural stability of the transmembrane α-bundle: the formation of extensive networks of interhelical H-bonds and sulfur-aromatic clusters that are spatially organized as 'polarity gradients' the close packing of side-chains throughout the transmembrane domain; and the formation of interhelical disulfide bonds in some receptors and a plausible Zn2+ binding center in retinochrome. Other features of the models are related to biological function and evolution of GPCRs: the formation of a common 'minicore' of 43 evolutionarily conserved residues; a multitude of correlated replacements throughout the transmembrane domain; an Na+-binding site in some receptors, and excellent complementarity of receptor binding pockets to many structurally dissimilar, conformationally constrained ligands, such as retinal, cyclic opioid peptides, and cationic amine ligands. The calculated models are in good agreement with numerous experimental data.

  19. Portraying G Protein-Coupled Receptors with Fluorescent Ligands

    Science.gov (United States)

    2015-01-01

    The thermodynamics of ligand–receptor interactions at the surface of living cells represents a fundamental aspect of G protein-coupled receptor (GPCR) biology; thus, its detailed elucidation constitutes a challenge for modern pharmacology. Interestingly, fluorescent ligands have been developed for a variety of GPCRs in order to monitor ligand–receptor binding in living cells. Accordingly, new methodological strategies derived from noninvasive fluorescence-based approaches, especially fluorescence resonance energy transfer (FRET), have been successfully developed to characterize ligand–receptor interactions. Importantly, these technologies are supplanting more hazardous and expensive radioactive binding assays. In addition, FRET-based tools have also become extremely powerful approaches for visualizing receptor–receptor interactions (i.e., GPCR oligomerization) in living cells. Thus, by means of the synthesis of compatible fluorescent ligands these novel techniques can be implemented to demonstrate the existence of GPCR oligomerization not only in heterologous systems but also in native tissues. Finally, there is no doubt that these methodologies would also be relevant in drug discovery in order to develop new high-throughput screening approaches or to identify new therapeutic targets. Overall, herein, we provide a thorough assessment of all technical and biological aspects, including strengths and weaknesses, of these fluorescence-based methodologies when applied to the study of GPCR biology at the plasma membrane of living cells. PMID:25010291

  20. Sigma 1 receptor modulation of G-protein-coupled receptor signaling: potentiation of opioid transduction independent from receptor binding.

    Science.gov (United States)

    Kim, Felix J; Kovalyshyn, Ivanka; Burgman, Maxim; Neilan, Claire; Chien, Chih-Cheng; Pasternak, Gavril W

    2010-04-01

    sigma Ligands modulate opioid actions in vivo, with agonists diminishing morphine analgesia and antagonists enhancing the response. Using human BE(2)-C neuroblastoma cells that natively express opioid receptors and human embryonic kidney (HEK) cells transfected with a cloned mu opioid receptor, we now demonstrate a similar modulation of opioid function, as assessed by guanosine 5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTP gamma S) binding, by sigma(1) receptors. sigma Ligands do not compete opioid receptor binding. Administered alone, neither sigma agonists nor antagonists significantly stimulated [(35)S]GTP gamma S binding. Yet sigma receptor selective antagonists, but not agonists, shifted the EC(50) of opioid-induced stimulation of [(35)S]GTP gamma S binding by 3- to 10-fold to the left. This enhanced potency was seen without a change in the efficacy of the opioid, as assessed by the maximal stimulation of [(35)S]GTP gamma S binding. sigma(1) Receptors physically associate with mu opioid receptors, as shown by coimmunoprecipitation studies in transfected HEK cells, implying a direct interaction between the proteins. Thus, sigma receptors modulate opioid transduction without influencing opioid receptor binding. RNA interference knockdown of sigma(1) in BE(2)-C cells also potentiated mu opioid-induced stimulation of [(35)S]GTP gamma S binding. These modulatory actions are not limited to mu and delta opioid receptors. In mouse brain membrane preparations, sigma(1)-selective antagonists also potentiated both opioid receptor and muscarinic acetylcholine receptor-mediated stimulation of [(35)S]GTP gamma S binding, suggesting a broader role for sigma receptors in modulating G-protein-coupled receptor signaling.

  1. Implementation of a fluorescence-based screening assay identifies histamine H3 receptor antagonists clobenpropit and iodophenpropit as subunit-selective N-methyl-D-aspartate receptor antagonists

    DEFF Research Database (Denmark)

    Hansen, Kasper Bø; Mullasseril, Praseeda; Dawit, Sara

    2010-01-01

    N-Methyl-D-aspartate (NMDA) receptors are ligand-gated ion channels that mediate a slow, Ca(2+)-permeable component of excitatory synaptic transmission in the central nervous system and play a pivotal role in synaptic plasticity, neuronal development, and several neurological diseases. We describ...

  2. Recent Progress in Understanding Subtype Specific Regulation of NMDA Receptors by G Protein Coupled Receptors (GPCRs

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2014-02-01

    Full Text Available G Protein Coupled Receptors (GPCRs are the largest family of receptors whose ligands constitute nearly a third of prescription drugs in the market. They are widely involved in diverse physiological functions including learning and memory. NMDA receptors (NMDARs, which belong to the ionotropic glutamate receptor family, are likewise ubiquitously expressed in the central nervous system (CNS and play a pivotal role in learning and memory. Despite its critical contribution to physiological and pathophysiological processes, few pharmacological interventions aimed directly at regulating NMDAR function have been developed to date. However, it is well established that NMDAR function is precisely regulated by cellular signalling cascades recruited downstream of G protein coupled receptor (GPCR stimulation. Accordingly, the downstream regulation of NMDARs likely represents an important determinant of outcome following treatment with neuropsychiatric agents that target selected GPCRs. Importantly, the functional consequence of such regulation on NMDAR function varies, based not only on the identity of the GPCR, but also on the cell type in which relevant receptors are expressed. Indeed, the mechanisms responsible for regulating NMDARs by GPCRs involve numerous intracellular signalling molecules and regulatory proteins that vary from one cell type to another. In the present article, we highlight recent findings from studies that have uncovered novel mechanisms by which selected GPCRs regulate NMDAR function and consequently NMDAR-dependent plasticity.

  3. G protein-coupled receptor modulation with pepducins

    DEFF Research Database (Denmark)

    Dimond, Patricia; Carlson, Kenneth; Bouvier, Michel

    2011-01-01

    At the 2nd Pepducin Science Symposium held in Cambridge, Massachusetts, on November 4-5, 2010, investigators working in G protein-coupled receptor (GPCR) research convened to discuss progress since last year's inaugural conference. This year's symposium focused on increasing knowledge of the stru......At the 2nd Pepducin Science Symposium held in Cambridge, Massachusetts, on November 4-5, 2010, investigators working in G protein-coupled receptor (GPCR) research convened to discuss progress since last year's inaugural conference. This year's symposium focused on increasing knowledge...... of the structure and function of this ubiquitous superfamily of membrane receptors and their potential modulation for disease treatment. Presentations also focused on how GPCR mechanisms might be exploited to treat diseases with pepducins, novel synthetic lipopeptide pharmacophores that modulate heptahelical GPCR...... activity. While the multiple roles of GPCRs in physiological and pathophysiological processes offer significant opportunities for novel drug development, the global nature of their activity challenges drug-specific and validated target identification. This year's conference highlighted advances...

  4. Biosensor cell assay for measuring real-time aldosterone-induced release of histamine from mesenteric arteries

    DEFF Research Database (Denmark)

    Dalgaard, Emil G; Andersen, Kenneth; Svenningsen, Per

    2017-01-01

    AIMS: The aims were to develop a method for real-time detection of histamine release and to test if incubation with aldosterone induces histamine release from isolated, perfused mice mesenteric arteries. METHODS: Fura-2 loaded HEK-293 cells transfected with the histamine H1 receptor was used...... as a sensitive biosensor assay for histamine release from isolated mouse mesenteric arteries. Activation of the H1 receptor by histamine was measured as an increased number of intracellular Ca(2+) transient peaks using fluorescence imaging RESULTS: The developed biosensor was sensitive to histamine...... by the histamine H1 blocker pyrilamine. Mesenteric arteries from mast cell deficient SASH mice induced similar pyrilamine-sensitive Ca(2+) transient response in the biosensor cells. Mesenteric arteries from wild type and SASH mice expressed histamine decarboxylase mRNA, indicating that mast cells are not the only...

  5. Stress-induced release of anterior pituitary hormones: Effect of H3 receptor-mediated inhibition of histaminergic activity or posterior hypothalamic lesion

    DEFF Research Database (Denmark)

    Knigge, U.; Søe-Jensen, P.; Jørgensen, Henrik

    1999-01-01

    Histamine receptors, corticotropin, *Gb-endorphin, prolactin, adrenal steroids, stress, endotoxin, serotonin......Histamine receptors, corticotropin, *Gb-endorphin, prolactin, adrenal steroids, stress, endotoxin, serotonin...

  6. Molecular basis for amino acid sensing by family C G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Wellendorph, Petrine; Bräuner-Osborne, Hans

    2009-01-01

    Family C of human G-protein-coupled receptors (GPCRs) is constituted by eight metabotropic glutamate receptors, two gamma-aminobutyric acid type B (GABA(B1-2)) subunits forming the heterodimeric GABA(B) receptor, the calcium-sensing receptor, three taste1 receptors (T1R1-3), a promiscuous L...

  7. G-protein-coupled receptors and tyrosine kinases: crossroads in cell signaling and regulation.

    Science.gov (United States)

    Gavi, Shai; Shumay, Elena; Wang, Hsien-yu; Malbon, Craig C

    2006-03-01

    G-protein-coupled receptors and protein tyrosine kinases represent two prominent pathways for cellular signaling. As our knowledge of cell signaling pathways mediated by the superfamily of G-protein-coupled receptors and the smaller family of receptor tyrosine kinases expands, so does our appreciation of how these two major signaling platforms share information and modulate each other, otherwise termed "cross-talk". Cross-talk between G-protein-coupled receptors and tyrosine kinases can occur at several levels, including the receptor-to-receptor level, and at crucial downstream points (e.g. phosphatidylinositol-3-kinase, Akt/protein kinase B and the mitogen-activated protein kinase cascade). Regulation of G-protein-coupled receptors by non-receptor tyrosine kinases, such as Src family members, also operates in signaling. A broader understanding of how G-protein-coupled receptors and tyrosine kinases cross-talk reveals new insights into signaling modalities in both health and disease.

  8. Novel Roles for Kv7 Channels in Shaping Histamine-Induced Contractions and Bradykinin-Dependent Relaxations in Pig Coronary Arteries

    Science.gov (United States)

    Chen, Xingjuan; Li, Wennan; Hiett, S. Christopher; Obukhov, Alexander G.

    2016-01-01

    Voltage-gated Kv7 channels are inhibited by agonists of Gq-protein-coupled receptors, such as histamine. Recent works have provided evidence that inhibition of vascular Kv7 channels may trigger vessel contractions. In this study, we investigated how Kv7 activity modulates the histamine-induced contractions in “healthy” and metabolic syndrome (MetS) pig right coronary arteries (CAs). We performed isometric tension and immunohistochemical studies with domestic, lean Ossabaw, and MetS Ossabaw pig CAs. We found that neither the Kv7.2/Kv7.4/Kv7.5 activator ML213 nor the general Kv7 inhibitor XE991 altered the tension of CA rings under preload, indicating that vascular Kv7 channels are likely inactive in the preloaded rings. Conversely, ML213 potently dilated histamine-pre-contracted CAs, suggesting that Kv7 channels are activated during histamine applications and yet partially inhibited by histamine. Immunohistochemistry analysis revealed strong Kv7.4 immunostaining in the medial and intimal layers of the CA wall, whereas Kv7.5 immunostaining intensity was strong in the intimal but weak in the medial layers. The medial Kv7 immunostaining was significantly weaker in MetS Ossabaw CAs as compared to lean Ossabaw or domestic CAs. Consistently, histamine-pre-contracted MetS Ossabaw CAs exhibited attenuated ML213-dependent dilations. In domestic pig CAs, where medial Kv7 immunostaining intensity was stronger, histamine-induced contractions spontaneously decayed to ~31% of the peak amplitude within 4 minutes. Oppositely, in Ossabaw CAs, where Kv7 immunostaining intensity was weaker, the histamine-induced contractions were more sustained. XE991 pretreatment significantly slowed the decay rate of histamine-induced contractions in domestic CAs, supporting the hypothesis that increased Kv7 activity correlates with a faster rate of histamine-induced contraction decay. Alternatively, XE991 significantly decreased the amplitude of bradykinin-dependent dilations in pre

  9. Insights into cellular signalling by G protein coupled receptor transactivation of cell surface protein kinase receptors.

    Science.gov (United States)

    Chaplin, Rebecca; Thach, Lyna; Hollenberg, Morley D; Cao, Yingnan; Little, Peter J; Kamato, Danielle

    2017-06-01

    G protein coupled receptor (GPCR) signalling is mediated by transactivation independent and transactivation dependent pathways. GPCRs transactivate protein tyrosine kinase receptors (PTKRs) and protein serine/threonine kinase receptors (PS/TKR). Since the initial observations of transactivation dependent signalling, there has been an effort to understand the mechanisms behind this phenomena. GPCR signalling has evolved to include biased signalling. Biased signalling, whereby selected ligands can activate the same GPCR that can generate multiple signals, but drive only a unique response. To date, there has been no focus on the ability of biased agonists to activate the PTKR and PS/TKR transactivation pathways differentially. As such, this represents a novel direction for future research. This review will discuss the main mechanisms of GPCR mediated receptor transactivation and the pathways involved in intracellular responses.

  10. Radiosynthesis and biodistribution of a histamine H{sub 3} receptor antagonist 4-[3-(4-piperidin-1-yl-but-1-ynyl)-[{sup 11}C]benzyl]-morpholine: evaluation of a potential PET ligand

    Energy Technology Data Exchange (ETDEWEB)

    Airaksinen, Anu J. [Department of Nuclear Medicine and PET Research, Location Radionuclide Center, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam (Netherlands); Jablonowski, Jill A. [Johnson and Johnson Pharmaceutical Research and Development LLC, San Diego, CA 92121 (United States); Mey, Margreet van der [Department of Nuclear Medicine and PET Research, Location Radionuclide Center, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam (Netherlands); Barbier, Ann J. [Johnson and Johnson Pharmaceutical Research and Development LLC, San Diego, CA 92121 (United States); Klok, Rob P. [Department of Nuclear Medicine and PET Research, Location Radionuclide Center, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam (Netherlands); Verbeek, Joost [Department of Nuclear Medicine and PET Research, Location Radionuclide Center, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam (Netherlands); Schuit, Robert [Department of Nuclear Medicine and PET Research, Location Radionuclide Center, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam (Netherlands); Herscheid, Jacobus D.M. [Department of Nuclear Medicine and PET Research, Location Radionuclide Center, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam (Netherlands); Leysen, Josee E. [Department of Nuclear Medicine and PET Research, Location Radionuclide Center, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam (Netherlands); Carruthers, Nicholas I. [Johnson and Johnson Pharmaceutical Research and Development LLC, San Diego, CA 92121 (United States); Lammertsma, Adriaan A. [Department of Nuclear Medicine and PET Research, Location Radionuclide Center, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam (Netherlands); Windhorst, Albert D. [Department of Nuclear Medicine and PET Research, Location Radionuclide Center, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam (Netherlands)]. E-mail: bwindhorst@rnc.vu.nl

    2006-08-15

    The potent histamine H{sub 3} receptor antagonist JNJ-10181457 () was successfully labeled with {sup 11}C in a novel one-pot reaction sequence, with high chemical yield (decay-corrected yield, 28{+-}8%) and high specific radioactivity (56{+-}26 GBq/{mu}mol). The binding of [{sup 11}C] to H{sub 3} receptors was studied in vitro in rat brain and in vivo in rats and mice. The in vitro binding of [{sup 11}C] in rat coronal brain slices showed high binding in the striatum, and this binding was blocked by histamine and by two known H{sub 3} antagonists, JNJ-5207852 () and unlabeled Compound (), in a concentration-dependent manner. The biodistribution of [{sup 11}C] in rats was measured at 5, 10, 30 and 60 min. The uptake of [{sup 11}C] in regions rich in H{sub 3} receptors was highest at 30 min, giving 0.98%, 1.41%, 1.28% and 1.72% dose/g for the olfactory bulb, hippocampus, striatum and cerebral cortex, respectively. However, the binding of [{sup 11}C] in the rat brain could not be blocked by pretreatment with either Compound () (30 min or 24 h pretreatment) or cold Compound () (30-min pretreatment). The biodistribution of [{sup 11}C] in a second species (Balb/c mice) showed a higher overall uptake of the radioligand with an average brain uptake of 8.9% dose/g. In C57BL/6-H{sub 3}(-/-) knockout mice, a higher brain uptake was also observed. Analyses of metabolites and plasma protein binding were also undertaken. It appeared that [{sup 11}C] could not specifically label H{sub 3} receptors in rodent brain in vivo. Possible causes are discussed.

  11. Characterization of G-protein coupled receptor kinase interaction with the neurokinin-1 receptor using bioluminescence resonance energy transfer

    DEFF Research Database (Denmark)

    Jorgensen, Rasmus; Holliday, Nicholas D; Hansen, Jakob L

    2007-01-01

    To analyze the interaction between the neurokinin-1 (NK-1) receptor and G-protein coupled receptor kinases (GRKs), we performed bioluminescence resonance energy transfer(2) (BRET(2)) measurements between the family A NK-1 receptor and GRK2 and GRK5 as well as their respective kinase-inactive muta......To analyze the interaction between the neurokinin-1 (NK-1) receptor and G-protein coupled receptor kinases (GRKs), we performed bioluminescence resonance energy transfer(2) (BRET(2)) measurements between the family A NK-1 receptor and GRK2 and GRK5 as well as their respective kinase...

  12. Regulation of G Protein-Coupled Receptors by Ubiquitination

    Directory of Open Access Journals (Sweden)

    Kamila Skieterska

    2017-04-01

    Full Text Available G protein-coupled receptors (GPCRs comprise the largest family of membrane receptors that control many cellular processes and consequently often serve as drug targets. These receptors undergo a strict regulation by mechanisms such as internalization and desensitization, which are strongly influenced by posttranslational modifications. Ubiquitination is a posttranslational modification with a broad range of functions that is currently gaining increased appreciation as a regulator of GPCR activity. The role of ubiquitination in directing GPCRs for lysosomal degradation has already been well-established. Furthermore, this modification can also play a role in targeting membrane and endoplasmic reticulum-associated receptors to the proteasome. Most recently, ubiquitination was also shown to be involved in GPCR signaling. In this review, we present current knowledge on the molecular basis of GPCR regulation by ubiquitination, and highlight the importance of E3 ubiquitin ligases, deubiquitinating enzymes and β-arrestins. Finally, we discuss classical and newly-discovered functions of ubiquitination in controlling GPCR activity.

  13. G-Protein Coupled Receptors: Surface Display and Biosensor Technology

    Science.gov (United States)

    McMurchie, Edward; Leifert, Wayne

    Signal transduction by G-protein coupled receptors (GPCRs) underpins a multitude of physiological processes. Ligand recognition by the receptor leads to the activation of a generic molecular switch involving heterotrimeric G-proteins and guanine nucleotides. With growing interest and commercial investment in GPCRs in areas such as drug targets, orphan receptors, high-throughput screening of drugs and biosensors, greater attention will focus on assay development to allow for miniaturization, ultrahigh-throughput and, eventually, microarray/biochip assay formats that will require nanotechnology-based approaches. Stable, robust, cell-free signaling assemblies comprising receptor and appropriate molecular switching components will form the basis of future GPCR/G-protein platforms, which should be able to be adapted to such applications as microarrays and biosensors. This chapter focuses on cell-free GPCR assay nanotechnologies and describes some molecular biological approaches for the construction of more sophisticated, surface-immobilized, homogeneous, functional GPCR sensors. The latter points should greatly extend the range of applications to which technologies based on GPCRs could be applied.

  14. Allosteric modulation of G-protein coupled receptors

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Spalding, Tracy A

    2004-01-01

    The superfamily of G-protein coupled receptors (GPCRs) has more than 1000 members and is the largest family of proteins in the body. GPCRs mediate signalling of stimuli as diverse as light, ions, small molecules, peptides and proteins and are the targets for many pharmaceuticals. Most GPCR ligands....... In recent years, combinatorial chemistry and high throughput screening have helped identify several allosteric GPCR modulators with novel structures, several of which already have become valuable pharmacological tools and may be candidates for clinical testing in the near future. This mini review outlines...... the current status and perspectives of allosteric modulation of GPCR function with emphasis on the pharmacology of endogenous and synthesised modulators, their receptor interactions and the therapeutic prospects of allosteric ligands compared to orthosteric ligands....

  15. The structure and function of G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Rosenbaum, Daniel M; Rasmussen, Søren Gøgsig Faarup; Kobilka, Brian K

    2009-01-01

    G-protein-coupled receptors (GPCRs) mediate most of our physiological responses to hormones, neurotransmitters and environmental stimulants, and so have great potential as therapeutic targets for a broad spectrum of diseases. They are also fascinating molecules from the perspective of membrane......-protein structure and biology. Great progress has been made over the past three decades in understanding diverse GPCRs, from pharmacology to functional characterization in vivo. Recent high-resolution structural studies have provided insights into the molecular mechanisms of GPCR activation and constitutive...

  16. Dissecting signaling and functions of adhesion G protein-coupled receptors

    NARCIS (Netherlands)

    Araç, Demet; Aust, Gabriela; Calebiro, Davide; Engel, Felix B.; Formstone, Caroline; Goffinet, André; Hamann, Jörg; Kittel, Robert J.; Liebscher, Ines; Lin, Hsi-Hsien; Monk, Kelly R.; Petrenko, Alexander; Piao, Xianhua; Prömel, Simone; Schiöth, Helgi B.; Schwartz, Thue W.; Stacey, Martin; Ushkaryov, Yuri A.; Wobus, Manja; Wolfrum, Uwe; Xu, Lei; Langenhan, Tobias

    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

  17. The Target Residence Time of Antihistamines Determines Their Antagonism of the G Protein-Coupled Histamine H1 Receptor

    NARCIS (Netherlands)

    Bosma, Reggie; Witt, Gesa; Vaas, Lea A I; Josimovic, Ivana; Gribbon, Philip; Vischer, Henry F; Gul, Sheraz; Leurs, Rob

    2017-01-01

    The pharmacodynamics of drug-candidates is often optimized by metrics that describe target binding (Kd or Ki value) or target modulation (IC50). However, these metrics are determined at equilibrium conditions, and consequently information regarding the onset and offset of target engagement and

  18. Receptor recruitment: A mechanism for interactions between G protein-coupled receptors

    OpenAIRE

    Holtbäck, Ulla; Brismar, Hjalmar; DiBona, Gerald F.; Fu, Michael; Greengard, Paul; Aperia, Anita

    1999-01-01

    There is a great deal of evidence for synergistic interactions between G protein-coupled signal transduction pathways in various tissues. As two specific examples, the potent effects of the biogenic amines norepinephrine and dopamine on sodium transporters and natriuresis can be modulated by neuropeptide Y and atrial natriuretic peptide, respectively. Here, we report, using a renal epithelial cell line, that both types of modulation involve recruitment of receptors from the interior of the ce...

  19. Histamine Induces Vascular Hyperpermeability by Increasing Blood Flow and Endothelial Barrier Disruption In Vivo

    Science.gov (United States)

    Ashina, Kohei; Tsubosaka, Yoshiki; Nakamura, Tatsuro; Omori, Keisuke; Kobayashi, Koji; Hori, Masatoshi; Ozaki, Hiroshi; Murata, Takahisa

    2015-01-01

    Histamine is a mediator of allergic inflammation released mainly from mast cells. Although histamine strongly increases vascular permeability, its precise mechanism under in vivo situation remains unknown. We here attempted to reveal how histamine induces vascular hyperpermeability focusing on the key regulators of vascular permeability, blood flow and endothelial barrier. Degranulation of mast cells by antigen-stimulation or histamine treatment induced vascular hyperpermeability and tissue swelling in mouse ears. These were abolished by histamine H1 receptor antagonism. Intravital imaging showed that histamine dilated vasculature, increased blood flow, while it induced hyperpermeability in venula. Whole-mount staining showed that histamine disrupted endothelial barrier formation of venula indicated by changes in vascular endothelial cadherin (VE-cadherin) localization at endothelial cell junction. Inhibition of nitric oxide synthesis (NOS) by L-NAME or vasoconstriction by phenylephrine strongly inhibited the histamine-induced blood flow increase and hyperpermeability without changing the VE-cadherin localization. In vitro, measurements of trans-endothelial electrical resistance of human dermal microvascular endothelial cells (HDMECs) showed that histamine disrupted endothelial barrier. Inhibition of protein kinase C (PKC) or Rho-associated protein kinase (ROCK), NOS attenuated the histamine-induced barrier disruption. These observations suggested that histamine increases vascular permeability mainly by nitric oxide (NO)-dependent vascular dilation and subsequent blood flow increase and maybe partially by PKC/ROCK/NO-dependent endothelial barrier disruption. PMID:26158531

  20. Histamine Potentiates Cyclosomatostatin-Induced Catalepsy in Old Rats

    Directory of Open Access Journals (Sweden)

    Ionov

    2015-05-01

    Full Text Available Background The decreased level of somatostatin and increased level of histamine are detected in the Parkinsonian brain. In old Wistar rats, the brain somatostatin deficiency can initiate catalepsy that suggests the pathogenic significance of this abnormality in Parkinson’s disease (PD. The ability of histamine to affect the somatostatin deficiency action is not studied. Objectives The current study aimed to examine if histamine alters the cataleptogenic activity of the brain somatostatin deficiency in Wistar rats. Materials and Methods The animals used in the study were 100 - 110 and 736 - 767 days old. Catalepsy was evaluated by the bar test. The inhibition of the brain somatostatin activity was simulated by I.C.V. administration of cyclosomatostatin (cycloSOM, a somatostatin receptor antagonist. Results CycloSOM (0.2, 1.0, and 5.0 µg and histamine (1.0 and 10.0 µg alone were ineffective in both young and old animals. In combination, however, cycloSOM and histamine initiated cataleptic response in old rats. Effect of the combination was inhibited by H1 and H2 but not H3 antagonists. Conclusions CycloSOM and histamine synergistically exert catalepsy in old rats. In light of these data, the combination of the decreased brain level of somatostatin and increased brain level of histamine may be of pathogenic relevance for extrapyramidal signs in PD.

  1. Histamine Food Poisoning.

    Science.gov (United States)

    Schirone, Maria; Visciano, Pierina; Tofalo, Rosanna; Suzzi, Giovanna

    2017-01-01

    The consumption of food containing high amounts of histamine and other biogenic amines can cause food poisoning with different symptoms linked to the individual sensitivity and the detoxification activity. Histamine is the only biogenic amine with regulatory limits set by the European Commission in fish and fishery products, because it can lead to a fatal outcome. However, also fermented foods can be involved in outbreaks and sporadic cases of intoxication. The factors affecting the presence of histamine in food are variable and product specific including the availability of the precursor amino acid, the presence of microorganisms producing decarboxylases, and the conditions allowing their growth and enzyme production. Generally, the good quality of raw material and hygienic practices during food processing as well as the use of histidine decarboxylase-negative starter cultures can minimize the occurrence of histamine. Further studies are necessary to estimate the human exposure and the relationship between the total amount of the biogenic amines ingested with food and health effects.

  2. G Protein-Coupled Receptor Multimers : A Question Still Open Despite the Use of Novel Approaches

    NARCIS (Netherlands)

    Vischer, Henry F; Castro, Marián; Pin, Jean Philippe

    Heteromerization of G protein-coupled receptors (GPCRs) can significantly change the functional properties of involved receptors. Various biochemical and biophysical methodologies have been developed in the last two decades to identify and functionally evaluate GPCR heteromers in heterologous cells,

  3. Angiotensin-(1-7) Is an Endogenous Ligand for the G Protein-Coupled Receptor Mas

    National Research Council Canada - National Science Library

    Robson A. S. Santos; Ana C. Simoes e Silva; Christine Maric; Denise M. R. Silva; Raquel Pillar Machado; Insa de Buhr; Silvia Heringer-Walther; Sergio Veloso B. Pinheiro; Myriam Teresa Lopes; Michael Bader; Elizabeth P. Mendes; Virgina Soares Lemos; Maria Jose Campagnole-Santos; Heinz-Peter Schultheiss; Robert Speth; Thomas Walther

    2003-01-01

    ...) antagonist indicated the existence of a distinct Ang-(1-7) receptor. We demonstrate that genetic deletion of the G protein-coupled receptor encoded by the Mas protooncogene abolishes the binding of Ang-(1-7) to mouse kidneys...

  4. Histamine suppresses epidermal keratinocyte differentiation and impairs skin barrier function in a human skin model

    OpenAIRE

    Gschwandtner, M; Mildner, M.; Mlitz, V; Gruber, F; Eckhart, L; Werfel, T.; Gutzmer, R.; Elias, P M; Tschachler, E.

    2012-01-01

    Background Defects in keratinocyte differentiation and skin barrier are important features of inflammatory skin diseases like atopic dermatitis. Mast cells and their main mediator histamine are abundant in inflamed skin and thus may contribute to disease pathogenesis. Methods Human primary keratinocytes were cultured under differentiation-promoting conditions in the presence and absence of histamine, histamine receptor agonists and antagonists. The expression of differentiation-associated gen...

  5. Seven transmembrane G protein-coupled receptor repertoire of gastric ghrelin cells

    DEFF Research Database (Denmark)

    Engelstoft, Maja S; Park, Won-Mee; Sakata, Ichiro

    2013-01-01

    The molecular mechanisms regulating secretion of the orexigenic-glucoregulatory hormone ghrelin remain unclear. Based on qPCR analysis of FACS-purified gastric ghrelin cells, highly expressed and enriched 7TM receptors were comprehensively identified and functionally characterized using in vitro......, ex vivo and in vivo methods. Five Gαs-coupled receptors efficiently stimulated ghrelin secretion: as expected the β1-adrenergic, the GIP and the secretin receptors but surprisingly also the composite receptor for the sensory neuropeptide CGRP and the melanocortin 4 receptor. A number of Gαi....../o-coupled receptors inhibited ghrelin secretion including somatostatin receptors SSTR1, SSTR2 and SSTR3 and unexpectedly the highly enriched lactate receptor, GPR81. Three other metabolite receptors known to be both Gαi/o- and Gαq/11-coupled all inhibited ghrelin secretion through a pertussis toxin-sensitive Gαi...

  6. Regulation of neuronal communication by G protein-coupled receptors.

    Science.gov (United States)

    Huang, Yunhong; Thathiah, Amantha

    2015-06-22

    Neuronal communication plays an essential role in the propagation of information in the brain and requires a precisely orchestrated connectivity between neurons. Synaptic transmission is the mechanism through which neurons communicate with each other. It is a strictly regulated process which involves membrane depolarization, the cellular exocytosis machinery, neurotransmitter release from synaptic vesicles into the synaptic cleft, and the interaction between ion channels, G protein-coupled receptors (GPCRs), and downstream effector molecules. The focus of this review is to explore the role of GPCRs and G protein-signaling in neurotransmission, to highlight the function of GPCRs, which are localized in both presynaptic and postsynaptic membrane terminals, in regulation of intrasynaptic and intersynaptic communication, and to discuss the involvement of astrocytic GPCRs in the regulation of neuronal communication. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  7. Sphingolipids in the function of G protein-coupled receptors.

    Science.gov (United States)

    Jafurulla, Mohammad; Chattopadhyay, Amitabha

    2015-09-15

    G protein-coupled receptors (GPCRs) constitute the largest and most diverse protein family in mammals and are involved in information transfer across cellular membranes. GPCRs are known to regulate multiple physiological functions and therefore represent major drug targets in all clinical areas. The fact that GPCRs are integral membrane proteins raises the possibility of their interaction with functionally important membrane lipids such as sphingolipids. Sphingolipids are essential membrane components and are recognized as diverse and dynamic regulators of a multitude of cellular processes. Interaction with sphingolipids could lead to modulation of GPCR structure and function. In this review, we highlight the role of sphingolipids in the function of GPCRs with specific examples. A comprehensive understanding of molecular events involved in GPCR-lipid interaction would provide better insight into GPCR function in health and disease. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. G-protein-coupled receptors as fat sensors.

    Science.gov (United States)

    Vinolo, Marco A R; Hirabara, Sandro M; Curi, Rui

    2012-03-01

    It has been demonstrated that fatty acids (FAs) are physiological ligands of G-protein-coupled receptors (GPRs). Activation of the GPRs (40, 41, 43, 84, 119 and 120) by FAs or synthetic agonists modulates several responses. In this review, we discuss the current knowledge on the actions of FA-activated GPRs and their relevance in normal and pathological conditions. Studies have shown that FA-activated GPRs modulate hormone secretion (incretin, insulin and glucagon), activation of leukocytes and several aspects of metabolism. Understanding GPR actions and their involvement in the development of insulin-resistance, β-cell failure, dyslipidemia and inflammation associated with obesity, type 2 diabetes, metabolic syndrome and cardiovascular diseases is important for the comprehension of the mechanisms underlying these pathological conditions and for the establishment of new and effective interventions.

  9. G protein-coupled receptors as regulators of energy homeostasis.

    Science.gov (United States)

    Tao, Ya-Xiong; Yuan, Zong-Hui; Xie, Jun

    2013-01-01

    G protein-coupled receptors (GPCRs) are versatile regulators of physiological processes. They are also important drug targets. Many of the molecules controlling energy homeostasis act through GPCRs. This article summarizes the regulators of energy homeostasis in the central nervous system: those secreted by the gastrointestinal peptides and those secreted by the endocrine pancreas. Some examples of orphan GPCRs are also given. The regulation of energy homeostasis is conserved in other mammals, including those species relevant in veterinary medicine, and fish. Finally, the genetics of human obesity is briefly summarized. Genetic susceptibility in the current obesogenic environment is likely causing the obesity pandemic. A better understanding of the regulation of energy homeostasis will lead to novel pharmacotherapy for obesity treatment. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. G-Protein-Coupled Receptors in Adult Neurogenesis

    Science.gov (United States)

    Doze, Van A.

    2012-01-01

    The importance of adult neurogenesis has only recently been accepted, resulting in a completely new field of investigation within stem cell biology. The regulation and functional significance of adult neurogenesis is currently an area of highly active research. G-protein-coupled receptors (GPCRs) have emerged as potential modulators of adult neurogenesis. GPCRs represent a class of proteins with significant clinical importance, because approximately 30% of all modern therapeutic treatments target these receptors. GPCRs bind to a large class of neurotransmitters and neuromodulators such as norepinephrine, dopamine, and serotonin. Besides their typical role in cellular communication, GPCRs are expressed on adult neural stem cells and their progenitors that relay specific signals to regulate the neurogenic process. This review summarizes the field of adult neurogenesis and its methods and specifies the roles of various GPCRs and their signal transduction pathways that are involved in the regulation of adult neural stem cells and their progenitors. Current evidence supporting adult neurogenesis as a model for self-repair in neuropathologic conditions, adult neural stem cell therapeutic strategies, and potential avenues for GPCR-based therapeutics are also discussed. PMID:22611178

  11. PUNISHING AND CARDIOVASCULAR EFFECTS OF INTRAVENOUS HISTAMINE IN RATS: PHARMACOLOGICAL SELECTIVITY

    Science.gov (United States)

    Podlesnik, Christopher A.; Jimenez-Gomez, Corina

    2014-01-01

    Although drugs may serve as reinforcers or punishers of operant behavior, the punishing function has received much less experimental attention than the reinforcing function. A sensitive method for studying drug-induced punishment is to assess choice for a punished response over an unpunished response. In these experiments, rats chose between pressing one lever and receiving a sucrose pellet or pressing another lever and receiving a sucrose pellet plus an intravenous injection of histamine. When sucrose was delivered equally frequently for either the punished or the unpunished response, rats selected the unpunished lever consistently, but decreases in the punished response did not differ as a function of intravenous histamine dose (0.1–1 mg/kg/inj). Changing the procedure so that sucrose was delivered on the unpunished lever with p = .5 increased the rats’ responding on the punished lever with saline injections. In addition, the same range of histamine doses produced a much larger range of responses on the punished lever that was dose dependent. Using these procedures to assess the receptors mediating histamine’s effects, the histamine H1-receptor antagonists, pyrilamine and ketotifen, antagonized the punishing effect of histamine, but the histamine H2-receptor antagonist ranitidine did not. However, ranitidine pretreatments reduced histamine-induced heart-rate increases to a greater extent than did the histamine H1-receptor antagonists when administered at the same doses examined under conditions of histamine punishment. Overall, the present findings extend the general hypothesis that activation of histamine H1-receptors mediates the punishing effects of histamine. They also introduce methods for rapidly assessing pharmacological mechanisms underlying drug-induced punishment. PMID:23982898

  12. In Vivo Histamine Optical Nanosensors

    Directory of Open Access Journals (Sweden)

    Heather A. Clark

    2012-08-01

    Full Text Available In this communication we discuss the development of ionophore based nanosensors for the detection and monitoring of histamine levels in vivo. This approach is based on the use of an amine-reactive, broad spectrum ionophore which is capable of recognizing and binding to histamine. We pair this ionophore with our already established nanosensor platform, and demonstrate in vitro and in vivo monitoring of histamine levels. This approach enables capturing rapid kinetics of histamine after injection, which are more difficult to measure with standard approaches such as blood sampling, especially on small research models. The coupling together of in vivo nanosensors with ionophores such as nonactin provide a way to generate nanosensors for novel targets without the difficult process of designing and synthesizing novel ionophores.

  13. Histamine, antihistamines, and the central nervous system.

    Science.gov (United States)

    Lieberman, Philip

    2009-01-01

    Histamine is a central nervous system (CNS) neurotransmitter. It acts in the brain via three receptors, H(1), H(2), and H(3). It is a mediator of "wakefulness" and its activity is necessary to maintain wakefulness, alertness, and reaction time. These activities can be impaired by H(1)-antagonists (reverse agonists) capable of penetrating the blood-brain barrier. By blocking the homeostatic effects of histamine in the CNS, drowsiness and functional impairment with or without drowsiness can occur. Several tests have been designed to assess the effects of antihistamines on the CNS. These include subjective measurements of drowsiness and more objective measurements of impairment. Second-generation antihistamines have been designed to minimize blood-brain barrier penetration by reducing lipophilicity and increasing the affinity for P-aminnoglycoprotein.

  14. An overview of anti-allergic drug therapy and the histamine-1 ...

    African Journals Online (AJOL)

    and corticosteroid medication (when indicated, and in most instances, used locally). The article provides an overview of the nature and the management of allergic disease and the histamine 1 antihistamines. Keywords: anti-allergic drug therapy, H1 antihistamines, histamine receptors, allergic rhinoconjunctivitis, allergy ...

  15. Pitolisant, an inverse agonist of the histamine H3 receptor: an alternative stimulant for narcolepsy-cataplexy in teenagers with refractory sleepiness.

    Science.gov (United States)

    Inocente, Clara; Arnulf, Isabelle; Bastuji, Hélène; Thibault-Stoll, Anne; Raoux, Aude; Reimão, Rubens; Lin, Jian-Sheng; Franco, Patricia

    2012-01-01

    Narcolepsy is a rare disabling sleep disorder characterized by excessive daytime sleepiness and cataplexy (sudden loss of muscle tone). Drugs such as pitolisant, which block histamine H3 autoreceptors, constitute a newly identified class of stimulants because they increase brain histamine and enhance wakefulness in animal and human adult narcolepsy. We report our experience with the off-label use of pitolisant in 4 teenagers with narcolepsy/cataplexy with severe daytime sleepiness, refractory to available treatments (modafinil, methylphenidate, mazindol, sodium oxybate, and D-amphetamine). All teenagers developed their disease during childhood (11.3 ± 2.4 years; 50% boys) and were 17.3 ± 0.8 years old at the time of pitolisant therapy. Pitolisant treatment was increased from 10 to 30 mg (n = 1) and 40 mg (n = 3). The adapted Epworth Sleepiness Score decreased from 14.3 ± 1.1 to 9.5 ± 2.9 (P = 0.03) with pitolisant alone to 7 ± 3.4 when combined with mazindol (n = 1), methylphenidate (n = 1), or sodium oxybate plus modafinil (n = 1). Mean sleep onset latency increased from 31 ± 14 minutes to 36 ± 8 minutes (P = 0.21) on the maintenance of wakefulness test. The severity and frequency of cataplexy were slightly improved. Adverse effects were minor (insomnia, headache, hot flushes, leg pain, and hallucinations) and transitory, except for insomnia, which persisted in 2 teenagers. The benefit was maintained after a mean of 13 months. Pitolisant could constitute an acceptable alternative for the treatment of refractory sleepiness in teenagers with narcolepsy.

  16. Roles of histamine on the expression of aldehyde dehydrogenase 1 in endometrioid adenocarcinoma cell line

    Science.gov (United States)

    Wang, Yi; Jiang, Yang; Ikeda, Jun-ichiro; Tian, Tian; Sato, Atsushi; Ohtsu, Hiroshi; Morii, Eiichi

    2014-01-01

    Cancer-initiating cells (CICs) are a limited number of cells that are essential for maintenance, recurrence, and metastasis of tumors. Aldehyde dehydrogenase 1 (ALDH1) has been recognized as a marker of CICs. We previously reported that ALDH1-high cases of uterine endometrioid adenocarcinoma showed poor prognosis, and that ALDH1 high population was more tumorigenic, invasive, and resistant to apoptosis than ALDH1 low population. Histamine plays a critical role in cancer cell proliferation, migration, and invasion. Here, we examined the effect of histamine on ALDH1 expression in endometrioid adenocarcinoma cell line. The addition of histamine increased ALDH1 high population, which was consistent with the result that histamine enhanced the invasive ability and the resistance to anticancer drug. Among 4 types of histamine receptors, histamine H1 and H2 receptor (H1R and H2R) were expressed in endometrioid adenocarcinoma cell line. The addition of H1R agonist but not H2R agonist increased ALDH1. The antagonist H1R but not H2R inhibited the effect of histamine on ALDH1 expression. These results indicated that histamine increased the expression of ALDH1 via H1R but not H2R. These findings may provide the evidence for exploring a new strategy to suppress CICs by inhibiting ALDH1 expression with histamine. PMID:25045085

  17. Arrhythmogenic effect of sympathetic histamine in mouse hearts subjected to acute ischemia.

    Science.gov (United States)

    He, Gonghao; Hu, Jing; Li, Teng; Ma, Xue; Meng, Jingru; Jia, Min; Lu, Jun; Ohtsu, Hiroshi; Chen, Zhong; Luo, Xiaoxing

    2012-02-10

    The role of histamine as a newly recognized sympathetic neurotransmitter has been presented previously, and its postsynaptic effects greatly depended on the activities of sympathetic nerves. Cardiac sympathetic nerves become overactivated under acute myocardial ischemic conditions and release neurotransmitters in large amounts, inducing ventricular arrhythmia. Therefore, it is proposed that cardiac sympathetic histamine, in addition to norepinephrine, may have a significant arrhythmogenic effect. To test this hypothesis, we observed the release of cardiac sympathetic histamine and associated ventricular arrhythmogenesis that was induced by acute ischemia in isolated mouse hearts. Mast cell-deficient mice (MCDM) and histidine decarboxylase knockout (HDC(-/-)) mice were used to exclude the potential involvement of mast cells. Electrical field stimulation and acute ischemia-reperfusion evoked chemical sympathectomy-sensitive histamine release from the hearts of both MCDM and wild-type (WT) mice but not from HDC(-/-) mice. The release of histamine from the hearts of MCDM and WT mice was associated with the development of acute ischemia-induced ventricular tachycardia and ventricular fibrillation. The incidence and duration of induced ventricular arrhythmias were found to decrease in the presence of the selective histamine H(2) receptor antagonist famotidine. Additionally, the released histamine facilitated the arrhythmogenic effect of simultaneously released norepinephrine. We conclude that, under acute ischemic conditions, cardiac sympathetic histamine released by overactive sympathetic nerve terminals plays a certain arrhythmogenic role via H(2) receptors. These findings provided novel insight into the pathophysiological roles of sympathetic histamine, which may be a new therapeutic target for acute ischemia-induced arrhythmias.

  18. Deletion of G-protein-coupled receptor 55 promotes obesity by reducing physical activity

    Science.gov (United States)

    Cannabinoid receptor 1 (CB1) is the best-characterized cannabinoid receptor, and CB1 antagonists are used in clinical trials to treat obesity. Because of the wide range of CB1 functions, the side effects of CB1 antagonists pose serious concerns. G-protein-coupled receptor 55 (GPR55) is an atypical c...

  19. Granule maturation in mast cells: histamine in control.

    Science.gov (United States)

    Hallgren, Jenny; Gurish, Michael F

    2014-01-01

    Mast cells are derived from committed progenitors that originate in the BM. They mature into histochemically distinguishable, metachromatic mast cells containing numerous cytoplasmic secretory granules. Accumulating evidence demonstrates that mast cell granule maturation is very tightly regulated by many factors including different granule components such as proteoglycans. In this issue of the European Journal of Immunology, Nakazawa et al. [Eur. J. Immunol. 2014. 44: 204-214] highlight a role for mast cell derived histamine as another factor critical for mast cell maturation. Using histidine decarboxylase (HDC) deficient mice that are unable to make histamine, they show poorly formed secretory granules and decreased secretory granule protease expression in peritoneal mast cells. Co-culturing BM-derived mast cells with fibroblasts normally drives granule maturation, but HDC-deficient BM-derived mast cells fail to do so. Exogenously provided histamine partly restores granule differentiation as evidenced by increased tryptase and chymase activity, and this is histamine receptor type H4 -dependent. However, H4 -deficient mice have intact granule formation in peritoneal mast cells, suggesting that when HDC is functional, the intrinsic histamine production is sufficient for most granule maturation processes and H4 is dispensable. This study highlights the role of histamine in the regulation of mast cell maturation, although the cytosolic target remains unknown. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. G-Protein Coupled Receptors Targeted by Analgesic Venom Peptides

    Directory of Open Access Journals (Sweden)

    James T. Daniel

    2017-11-01

    Full Text Available Chronic pain is a complex and debilitating condition associated with a large personal and socioeconomic burden. Current pharmacological approaches to treating chronic pain such as opioids, antidepressants and anticonvulsants exhibit limited efficacy in many patients and are associated with dose-limiting side effects that hinder their clinical use. Therefore, improved strategies for the pharmacological treatment of pathological pain are urgently needed. G-protein coupled receptors (GPCRs are ubiquitously expressed on the surface of cells and act to transduce extracellular signals and regulate physiological processes. In the context of pain, numerous and diverse families of GPCRs expressed in pain pathways regulate most aspects of physiological and pathological pain and are thus implicated as potential targets for therapy of chronic pain. In the search for novel compounds that produce analgesia via GPCR modulation, animal venoms offer an enormous and virtually untapped source of potent and selective peptide molecules. While many venom peptides target voltage-gated and ligand-gated ion channels to inhibit neuronal excitability and blunt synaptic transmission of pain signals, only a small proportion are known to interact with GPCRs. Of these, only a few have shown analgesic potential in vivo. Here we review the current state of knowledge regarding venom peptides that target GPCRs to produce analgesia, and their development as therapeutic compounds.

  1. G protein-coupled receptor kinase 2 promotes cardiac hypertrophy

    Science.gov (United States)

    Tscheschner, Henrike; Gao, Erhe; Schumacher, Sarah M.; Yuan, Ancai; Backs, Johannes; Most, Patrick; Wieland, Thomas; Koch, Walter J.; Katus, Hugo A.; Raake, Philip W.

    2017-01-01

    The increase in protein activity and upregulation of G-protein coupled receptor kinase 2 (GRK2) is a hallmark of cardiac stress and heart failure. Inhibition of GRK2 improved cardiac function and survival and diminished cardiac remodeling in various animal heart failure models. The aim of the present study was to investigate the effects of GRK2 on cardiac hypertrophy and dissect potential molecular mechanisms. In mice we observed increased GRK2 mRNA and protein levels following transverse aortic constriction (TAC). Conditional GRK2 knockout mice showed attenuated hypertrophic response with preserved ventricular geometry 6 weeks after TAC operation compared to wild-type animals. In isolated neonatal rat ventricular cardiac myocytes stimulation with angiotensin II and phenylephrine enhanced GRK2 expression leading to enhanced signaling via protein kinase B (PKB or Akt), consecutively inhibiting glycogen synthase kinase 3 beta (GSK3β), such promoting nuclear accumulation and activation of nuclear factor of activated T-cells (NFAT). Cardiac myocyte hypertrophy induced by in vitro GRK2 overexpression increased the cytosolic interaction of GRK2 and phosphoinositide 3-kinase γ (PI3Kγ). Moreover, inhibition of PI3Kγ as well as GRK2 knock down prevented Akt activation resulting in halted NFAT activity and reduced cardiac myocyte hypertrophy. Our data show that enhanced GRK2 expression triggers cardiac hypertrophy by GRK2-PI3Kγ mediated Akt phosphorylation and subsequent inactivation of GSK3β, resulting in enhanced NFAT activity. PMID:28759639

  2. GATA Factor-G-Protein-Coupled Receptor Circuit Suppresses Hematopoiesis

    Directory of Open Access Journals (Sweden)

    Xin Gao

    2016-03-01

    Full Text Available Hematopoietic stem cells (HSCs originate from hemogenic endothelium within the aorta-gonad-mesonephros (AGM region of the mammalian embryo. The relationship between genetic circuits controlling stem cell genesis and multi-potency is not understood. A Gata2 cis element (+9.5 enhances Gata2 expression in the AGM and induces the endothelial to HSC transition. We demonstrated that GATA-2 rescued hematopoiesis in +9.5−/− AGMs. As G-protein-coupled receptors (GPCRs are the most common targets for FDA-approved drugs, we analyzed the GPCR gene ensemble to identify GATA-2-regulated GPCRs. Of the 20 GATA-2-activated GPCR genes, four were GATA-1-activated, and only Gpr65 expression resembled Gata2. Contrasting with the paradigm in which GATA-2-activated genes promote hematopoietic stem and progenitor cell genesis/function, our mouse and zebrafish studies indicated that GPR65 suppressed hematopoiesis. GPR65 established repressive chromatin at the +9.5 site, restricted occupancy by the activator Scl/TAL1, and repressed Gata2 transcription. Thus, a Gata2 cis element creates a GATA-2-GPCR circuit that limits positive regulators that promote hematopoiesis.

  3. Alpha-Bulges in G Protein-Coupled Receptors

    Directory of Open Access Journals (Sweden)

    Rob van der Kant

    2014-05-01

    Full Text Available Agonist binding is related to a series of motions in G protein-coupled receptors (GPCRs that result in the separation of transmembrane helices III and VI at their cytosolic ends and subsequent G protein binding. A large number of smaller motions also seem to be associated with activation. Most helices in GPCRs are highly irregular and often contain kinks, with extensive literature already available about the role of prolines in kink formation and the precise function of these kinks. GPCR transmembrane helices also contain many α-bulges. In this article we aim to draw attention to the role of these α-bulges in ligand and G-protein binding, as well as their role in several aspects of the mobility associated with GPCR activation. This mobility includes regularization and translation of helix III in the extracellular direction, a rotation of the entire helix VI, an inward movement of the helices near the extracellular side, and a concerted motion of the cytosolic ends of the helices that makes their orientation appear more circular and that opens up space for the G protein to bind. In several cases, α-bulges either appear or disappear as part of the activation process.

  4. G-protein-coupled receptors for free fatty acids

    DEFF Research Database (Denmark)

    Milligan, Graeme; Ulven, Trond; Murdoch, Hannah

    2014-01-01

    that communicate cellular signals initiated by hormones and neurotransmitters. Recently, based on tissue expression patterns of these receptors and the concept that they may elicit the production of a range of appetite- and hunger-regulating peptides, such nutrient sensing GPCRs are attracting considerable...... of these receptors. However, ongoing clinical trials of agonists of free fatty acid receptor 1 suggest that this receptor and other receptors for free fatty acids may provide a successful strategy for controlling hyperglycaemia and providing novel approaches to treat diabetes. Receptors responsive to free fatty acid...

  5. Histamine and tryptase in nasal lavage fluid after allergen challenge

    DEFF Research Database (Denmark)

    Jacobi, H H; Skov, P S; Poulsen, L K

    1999-01-01

    BACKGROUND: Antihistamines (H1-receptor antagonists) act by competitive antagonism of histamine at H1-receptors. In addition, high concentrations of some antihistamines inhibit allergen-induced histamine release from mast cells in vitro. OBJECTIVE: The purpose of this study was to determine...... the effect of intranasal azelastine or systemic cetirizine (both potent antihistamines) on the allergen-induced release of mast-cell mediators from the human nasal mucosa in vivo. METHODS: Patients allergic to birch pollen (n = 11) and control subjects not allergic to birch pollen (n = 5) were included......, nasal allergen challenges were performed, and the number of sneezes were counted. In addition, nasal lavage fluid was collected, and the levels of mast-cell mediators (histamine and tryptase) were measured. RESULTS: The allergen challenge of patients allergic to pollen produced sneezing...

  6. Mast cell degranulation and de novo histamine formation contribute to sustained postexercise vasodilation in humans.

    Science.gov (United States)

    Romero, Steven A; McCord, Jennifer L; Ely, Matthew R; Sieck, Dylan C; Buck, Tahisha M; Luttrell, Meredith J; MacLean, David A; Halliwill, John R

    2017-03-01

    In humans, acute aerobic exercise elicits a sustained postexercise vasodilation within previously active skeletal muscle. This response is dependent on activation of histamine H1 and H2 receptors, but the source of intramuscular histamine remains unclear. We tested the hypothesis that interstitial histamine in skeletal muscle would be increased with exercise and would be dependent on de novo formation via the inducible enzyme histidine decarboxylase and/or mast cell degranulation. Subjects performed 1 h of unilateral dynamic knee-extension exercise or sham (seated rest). We measured the interstitial histamine concentration and local blood flow (ethanol washout) via skeletal muscle microdialysis of the vastus lateralis. In some probes, we infused either α-fluoromethylhistidine hydrochloride (α-FMH), a potent inhibitor of histidine decarboxylase, or histamine H1/H2-receptor blockers. We also measured interstitial tryptase concentrations, a biomarker of mast cell degranulation. Compared with preexercise, histamine was increased after exercise by a change (Δ) of 4.2 ± 1.8 ng/ml (P histamine in skeletal muscle increases with exercise and results from both de novo formation and mast cell degranulation. This suggests that exercise produces an anaphylactoid signal, which affects recovery, and may influence skeletal muscle blood flow during exercise.NEW & NOTEWORTHY Blood flow to previously active skeletal muscle remains elevated following an acute bout of aerobic exercise and is dependent on activation of histamine H1 and H2 receptors. The intramuscular source of histamine that drives this response to exercise has not been identified. Using intramuscular microdialysis in exercising humans, we show both mast cell degranulation and formation of histamine by histidine decarboxylase contributes to the histamine-mediated vasodilation that occurs following a bout of aerobic exercise. Copyright © 2017 the American Physiological Society.

  7. A ligand channel through the G protein coupled receptor opsin.

    Directory of Open Access Journals (Sweden)

    Peter W Hildebrand

    Full Text Available The G protein coupled receptor rhodopsin contains a pocket within its seven-transmembrane helix (TM structure, which bears the inactivating 11-cis-retinal bound by a protonated Schiff-base to Lys296 in TM7. Light-induced 11-cis-/all-trans-isomerization leads to the Schiff-base deprotonated active Meta II intermediate. With Meta II decay, the Schiff-base bond is hydrolyzed, all-trans-retinal is released from the pocket, and the apoprotein opsin reloaded with new 11-cis-retinal. The crystal structure of opsin in its active Ops* conformation provides the basis for computational modeling of retinal release and uptake. The ligand-free 7TM bundle of opsin opens into the hydrophobic membrane layer through openings A (between TM1 and 7, and B (between TM5 and 6, respectively. Using skeleton search and molecular docking, we find a continuous channel through the protein that connects these two openings and comprises in its central part the retinal binding pocket. The channel traverses the receptor over a distance of ca. 70 A and is between 11.6 and 3.2 A wide. Both openings are lined with aromatic residues, while the central part is highly polar. Four constrictions within the channel are so narrow that they must stretch to allow passage of the retinal beta-ionone-ring. Constrictions are at openings A and B, respectively, and at Trp265 and Lys296 within the retinal pocket. The lysine enforces a 90 degrees elbow-like kink in the channel which limits retinal passage. With a favorable Lys side chain conformation, 11-cis-retinal can take the turn, whereas passage of the all-trans isomer would require more global conformational changes. We discuss possible scenarios for the uptake of 11-cis- and release of all-trans-retinal. If the uptake gate of 11-cis-retinal is assigned to opening B, all-trans is likely to leave through the same gate. The unidirectional passage proposed previously requires uptake of 11-cis-retinal through A and release of photolyzed all

  8. G-protein-coupled receptors and islet function-implications for treatment of type 2 diabetes.

    Science.gov (United States)

    Winzell, Maria Sörhede; Ahrén, Bo

    2007-12-01

    Islet function is regulated by a number of different signals. A main signal is generated by glucose, which stimulates insulin secretion and inhibits glucagon secretion. The glucose effects are modulated by many factors, including hormones, neurotransmitters and nutrients. Several of these factors signal through guanine nucleotide-binding protein (G protein)-coupled receptors (GPCR). Examples of islet GPCR are GPR40 and GPR119, which are GPCR with fatty acids as ligands, the receptors for the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), the receptors for the islet hormones glucagon and somatostatin, the receptors for the classical neurotransmittors acetylcholine (ACh; M(3) muscarinic receptors) and noradrenaline (beta(2)- and alpha(2)-adrenoceptors) and for the neuropeptides pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP; PAC(1) and VPAC(2) receptors), cholecystokinin (CCK(A) receptors) and neuropeptide Y (NPY Y1 receptors). Other islet GPCR are the cannabinoid receptor (CB(1) receptors), the vasopressin receptors (V1(B) receptors) and the purinergic receptors (P(2Y) receptors). The islet GPCR couple mainly to adenylate cyclase and to phospholipase C (PLC). Since important pharmacological strategies for treatment of type 2 diabetes are stimulation of insulin secretion and inhibition of glucagon secretion, islet GPCR are potential drug targets. This review summarizes knowledge on islet GPCR.

  9. Neuronal histamine and cognitive symptoms in Alzheimer's disease.

    Science.gov (United States)

    Zlomuzica, Armin; Dere, Dorothea; Binder, Sonja; De Souza Silva, Maria Angelica; Huston, Joseph P; Dere, Ekrem

    2016-07-01

    Alzheimer's disease is a neurodegenerative disorder characterized by extracellular amyloid plaque deposits, mainly composed of amyloid-beta peptide and intracellular neurofibrillary tangles consisting of aggregated hyperphosphorylated tau protein. Amyloid-beta represents a neurotoxic proteolytic cleavage product of amyloid precursor protein. The progressive cognitive decline that is associated with Alzheimer's disease has been mainly attributed to a deficit in cholinergic neurotransmission due to the continuous degeneration of cholinergic neurons e.g. in the basal forebrain. There is evidence suggesting that other neurotransmitter systems including neuronal histamine also contribute to the development and maintenance of Alzheimer's disease-related cognitive deficits. Pathological changes in the neuronal histaminergic system of such patients are highly predictive of ensuing cognitive deficits. Furthermore, histamine-related drugs, including histamine 3 receptor antagonists, have been demonstrated to alleviate cognitive symptoms in Alzheimer's disease. This review summarizes findings from animal and clinical research on the relationship between the neuronal histaminergic system and cognitive deterioration in Alzheimer's disease. The significance of the neuronal histaminergic system as a promising target for the development of more effective drugs for the treatment of cognitive symptoms is discussed. Furthermore, the option to use histamine-related agents as neurogenesis-stimulating therapy that counteracts progressive brain atrophy in Alzheimer's disease is considered. This article is part of a Special Issue entitled 'Histamine Receptors'. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. G-protein coupled receptor expression patterns delineate medulloblastoma subgroups

    Science.gov (United States)

    2013-01-01

    Background Medulloblastoma is the most common malignant brain tumor in children. Genetic profiling has identified four principle tumor subgroups; each subgroup is characterized by different initiating mutations, genetic and clinical profiles, and prognoses. The two most well-defined subgroups are caused by overactive signaling in the WNT and SHH mitogenic pathways; less is understood about Groups 3 and 4 medulloblastoma. Identification of tumor subgroup using molecular classification is set to become an important component of medulloblastoma diagnosis and staging, and will likely guide therapeutic options. However, thus far, few druggable targets have emerged. G-protein coupled receptors (GPCRs) possess characteristics that make them ideal targets for molecular imaging and therapeutics; drugs targeting GPCRs account for 30-40% of all current pharmaceuticals. While expression patterns of many proteins in human medulloblastoma subgroups have been discerned, the expression pattern of GPCRs in medulloblastoma has not been investigated. We hypothesized that analysis of GPCR expression would identify clear subsets of medulloblastoma and suggest distinct GPCRs that might serve as molecular targets for both imaging and therapy. Results Our study found that medulloblastoma tumors fall into distinct clusters based solely on GPCR expression patterns. Normal cerebellum clustered separately from the tumor samples. Further, two of the tumor clusters correspond with high fidelity to the WNT and SHH subgroups of medulloblastoma. Distinct over-expressed GPCRs emerge; for example, LGR5 and GPR64 are significantly and uniquely over-expressed in the WNT subgroup of tumors, while PTGER4 is over-expressed in the SHH subgroup. Uniquely under-expressed GPCRs were also observed. Our key findings were independently validated using a large international dataset. Conclusions Our results identify GPCRs with potential to act as imaging and therapeutic targets. Elucidating tumorigenic pathways

  11. 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

  12. Lighting up G protein-coupled purinergic receptors with engineered fluorescent ligands

    Science.gov (United States)

    Ciruela, Francisco; Fernández-Dueñas, Víctor; Jacobson, Kenneth A.

    2015-01-01

    The use of G protein-coupled receptors fluorescent ligands is undergoing continuous expansion. In line with this, fluorescent agonists and antagonists of high affinity for G protein-coupled adenosine and P2Y receptors have been shown to be useful pharmacological probe compounds. Fluorescent ligands for A1R, A2AR, and A3R (adenosine receptors) and P2Y2R, P2Y4R, P2Y6R, and P2Y14R (nucleotide receptors) have been reported. Such ligands have been successfully applied to drug discovery and to GPCR characterization by flow cytometry, fluorescence correlation spectroscopy, fluorescence microscopy, fluorescence polarization, fluorescence resonance energy transfer and scanning confocal microscopy. Here we summarize recently reported and readily available representative fluorescent ligands of purinergic receptors. In addition, we pay special attention on the use of this family of fluorescent ligands revealing two main aspects of purinergic receptor biology, namely ligand binding and receptor oligomerization. PMID:25890205

  13. Selective histamine uptake rescues photo- and mechanoreceptor function of histidine decarboxylase-deficient Drosophila mutant.

    Science.gov (United States)

    Melzig, J; Burg, M; Gruhn, M; Pak, W L; Buchner, E

    1998-09-15

    In insects, histamine is found both in the peripheral nervous system (PNS) and in the CNS and is known to function as a fast neurotransmitter in photoreceptors that have been shown to express selectively the hdc gene. This gene codes for histidine decarboxylase (HDC), the enzyme for histamine synthesis. Fast neurotransmission requires the efficient removal of the transmitter from the synaptic cleft. Here we identify in Drosophila photo- and mechanoreceptors a histamine uptake mechanism that can restore the function of these receptors in mutants unable to synthesize histamine. When apparent null mutants for the hdc gene imbibe aqueous histamine solution or are genetically "rescued" by a transgene ubiquitously expressing histidine decarboxylase under heat-shock control, sufficient amounts of histamine selectively accumulate in photo- and mechanoreceptors to generate near-normal electrical responses in second-order visual interneurons and qualitatively to restore wild-type visual and mechanosensory behavior. This strongly supports the proposal that histamine functions as a fast neurotransmitter also in a certain class of mechanoreceptors. A set of CNS-intrinsic neurons that in the wild type contain high concentrations of histamine apparently lacks this uptake mechanism. We therefore speculate that histamine of intrinsic neurons may function as a neuromodulator rather than as a fast transmitter.

  14. G protein-coupled receptors not currently in the spotlight: free fatty acid receptor 2 and GPR35.

    Science.gov (United States)

    Milligan, Graeme

    2017-09-21

    It is widely appreciated that G protein-coupled receptors have been the most successfully exploited class of targets for the development of small molecule medicines. Despite this, to date, less than 15% of the non-olfactory G protein-coupled receptors in the human genome are the targets of a clinically used medicine. In many cases, this is likely to reflect a lack of understanding of the basic underpinning biology of many G protein-coupled receptors that are not currently in the spotlight, as well as a paucity of pharmacological tool compounds and appropriate animal models to test in vivo function of such G protein-coupled receptors in both normal physiology and in the context of disease. 'Open Innovation' arrangements, in which pharmaceutical companies and public-private partnerships provide wider access to tool compounds identified from ligand screening programmes, alongside enhanced medicinal chemistry support to convert such screening 'hits' into useful 'tool' compounds will provide important routes to improved understanding. However, in parallel, novel approaches to define and fully appreciate the selectivity and mode of action of such tool compounds, as well as better understanding of potential species orthologue variability in the pharmacology and/or signalling profile of a wide range of currently poorly understood and understudied G protein-coupled receptors, will be vital to fully exploit the therapeutic potential of this large target class. I consider these themes using as exemplars two G protein-coupled receptors, free fatty acid receptor 2 and GPR35. © 2017 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.

  15. Comparison of methods for intestinal histamine application

    DEFF Research Database (Denmark)

    Vind, S; Søondergaard, I; Poulsen, L K

    1991-01-01

    The study was conducted to investigate whether introduction of histamine in enterosoluble capsules produced the same amount of urinary histamine metabolites as that found after application of histamine through a duodeno-jejunal tube. Secondly, to examine whether a histamine-restrictive or a fast ...

  16. β2-Adrenergic ion-channel coupled receptors as conformational motion detectors.

    Directory of Open Access Journals (Sweden)

    Lydia N Caro

    Full Text Available Ion Channel-Coupled Receptors (ICCRs are artificial proteins comprised of a G protein-coupled receptor and a fused ion channel, engineered to couple channel gating to ligand binding. These novel biological objects have potential use in drug screening and functional characterization, in addition to providing new tools in the synthetic biology repertoire as synthetic K(+-selective ligand-gated channels. The ICCR concept was previously validated with fusion proteins between the K(+ channel Kir6.2 and muscarinic M(2 or dopaminergic D(2 receptors. Here, we extend the concept to the distinct, longer β(2-adrenergic receptor which, unlike M(2 and D(2 receptors, displayed barely detectable surface expression in our Xenopus oocyte expression system and did not couple to Kir6.2 when unmodified. Here, we show that a Kir6.2-binding protein, the N-terminal transmembrane domain of the sulfonylurea receptor, can greatly increase plasma membrane expression of β(2 constructs. We then demonstrate how engineering of both receptor and channel can produce β(2-Kir6.2 ICCRs. Specifically, removal of 62-72 residues from the cytoplasmic C-terminus of the receptor was required to enable coupling, suggesting that ligand-dependent conformational changes do not efficiently propagate to the distal C-terminus. Characterization of the β(2 ICCRs demonstrated that full and partial agonists had the same coupling efficacy, that an inverse agonist had no effect and that the stabilizing mutation E122 W reduced agonist-induced coupling efficacy without affecting affinity. Because the ICCRs are expected to report motions of the receptor C-terminus, these results provide novel insights into the conformational dynamics of the β(2 receptor.

  17. Histamine suppresses epidermal keratinocyte differentiation and impairs skin barrier function in a human skin model

    Science.gov (United States)

    Gschwandtner, M; Mildner, M; Mlitz, V; Gruber, F; Eckhart, L; Werfel, T; Gutzmer, R; Elias, P M; Tschachler, E

    2013-01-01

    Background Defects in keratinocyte differentiation and skin barrier are important features of inflammatory skin diseases like atopic dermatitis. Mast cells and their main mediator histamine are abundant in inflamed skin and thus may contribute to disease pathogenesis. Methods Human primary keratinocytes were cultured under differentiation-promoting conditions in the presence and absence of histamine, histamine receptor agonists and antagonists. The expression of differentiation-associated genes and epidermal junction proteins was quantified by real-time PCR, Western blot, and immunofluorescence labeling. The barrier function of human skin models was tested by the application of biotin as tracer molecule. Results The addition of histamine to human keratinocyte cultures and organotypic skin models reduced the expression of the differentiation-associated proteins keratin 1/10, filaggrin, and loricrin by 80–95%. Moreover, the addition of histamine to skin models resulted in the loss of the granular layer and thinning of the epidermis and stratum corneum by 50%. The histamine receptor H1R agonist, 2-pyridylethylamine, suppressed keratinocyte differentiation to the same extent as did histamine. Correspondingly, cetirizine, an antagonist of H1R, virtually abrogated the effect of histamine. The expression of tight junction proteins zona occludens-1, occludin, claudin-1, and claudin-4, as well as that of desmosomal junction proteins corneodesmosin and desmoglein-1, was down-regulated by histamine. The tracer molecule biotin readily penetrated the tight junction barrier of skin cultures grown in the presence of histamine, while their diffusion was completely blocked in nontreated controls. Conclusions Our findings suggest a new mechanism by which mast cell activation and histamine release contribute to skin barrier defects in inflammatory skin diseases. PMID:23157658

  18. Synergistic mucus secretion by histamine and IL-4 through TMEM16A in airway epithelium.

    Science.gov (United States)

    Kang, Ju Wan; Lee, Yong Hyuk; Kang, Min Jeong; Lee, Hyun Jae; Oh, Ryung; Min, Hyun Jin; Namkung, Wan; Choi, Jae Young; Lee, Sang Nam; Kim, Chang-Hoon; Yoon, Joo-Heon; Cho, Hyung-Ju

    2017-09-01

    Histamine is an important mediator of allergic reactions, and mucus hypersecretion is a major allergic symptom. However, the direct effect of histamine on mucus secretion from airway mucosal epithelia has not been clearly demonstrated. TMEM16A is a Ca2+-activated chloride channel, and it is closely related to fluid secretion in airway mucosal epithelia. We investigated whether histamine directly induces fluid secretion from epithelial cells or submucosal glands (SMG) and mechanisms related, therewith, in allergic airway diseases. In pig airway tissues from the nose or trachea, histamine was a potent secretagogue that directly induced strong responses. However, gland secretion from human nasal tissue was not induced by histamine, even in allergic rhinitis patients. Histamine type 1 receptor (H1R) and histamine type 2 receptor (H2R) were not noted in SMG by in situ hybridization. Cultured primary human nasal epithelial (NHE) cells were used for the measurement of short-circuit current changes with the Ussing chamber. Histamine-induced slight responses of anion secretions under normal conditions. The response was enhanced by IL-4 stimulation through TMEM16A, which might be related to fluid hypersecretion in allergic rhinitis. Pretreatment with IL-4 augmented the histamine response that was suppressed by a TMEM16A inhibitor. TMEM16A expression was enhanced by 24-h treatment of IL-4 in human nasal epithelial cells. The expression of TMEM16A was significantly elevated in an allergic rhinitis group, compared with a control group. We elucidated histamine-induced fluid secretions in synergy with IL-4 through TMEM16A in the human airway epithelium. In addition, we observed species differences between pigs and humans in terms of gland secretion of histamine. Copyright © 2017 the American Physiological Society.

  19. The repertoire of olfactory C family G protein-coupled receptors in zebrafish: candidate chemosensory receptors for amino acids

    Directory of Open Access Journals (Sweden)

    Ngai John

    2006-12-01

    Full Text Available Abstract Background Vertebrate odorant receptors comprise at least three types of G protein-coupled receptors (GPCRs: the OR, V1R, and V2R/V2R-like receptors, the latter group belonging to the C family of GPCRs. These receptor families are thought to receive chemosensory information from a wide spectrum of odorant and pheromonal cues that influence critical animal behaviors such as feeding, reproduction and other social interactions. Results Using genome database mining and other informatics approaches, we identified and characterized the repertoire of 54 intact "V2R-like" olfactory C family GPCRs in the zebrafish. Phylogenetic analysis – which also included a set of 34 C family GPCRs from fugu – places the fish olfactory receptors in three major groups, which are related to but clearly distinct from other C family GPCRs, including the calcium sensing receptor, metabotropic glutamate receptors, GABA-B receptor, T1R taste receptors, and the major group of V2R vomeronasal receptor families. Interestingly, an analysis of sequence conservation and selective pressure in the zebrafish receptors revealed the retention of a conserved sequence motif previously shown to be required for ligand binding in other amino acid receptors. Conclusion Based on our findings, we propose that the repertoire of zebrafish olfactory C family GPCRs has evolved to allow the detection and discrimination of a spectrum of amino acid and/or amino acid-based compounds, which are potent olfactory cues in fish. Furthermore, as the major groups of fish receptors and mammalian V2R receptors appear to have diverged significantly from a common ancestral gene(s, these receptors likely mediate chemosensation of different classes of chemical structures by their respective organisms.

  20. Docosahexaenoic acid, G protein-coupled receptors, and melanoma: is G protein-coupled receptor 40 a potential therapeutic target?

    Science.gov (United States)

    Nehra, Deepika; Pan, Amy H; Le, Hau D; Fallon, Erica M; Carlson, Sarah J; Kalish, Brian T; Puder, Mark

    2014-05-15

    To determine the effect of docosahexaenoic acid (DHA) on the growth of human melanoma in vitro and in vivo and to better understand the potential role of the G protein-coupled receptors (GPRs) in mediating this effect. For in vitro studies, human melanoma and control fibroblast cells were treated with DHA and TAK-875 (selective GPR40 agonist) and a cell viability assay was performed to determine cell counts. A murine subcutaneous xenograft model of human melanoma was used to test the effect of dietary treatment with an omega-3 fatty acid (FA) rich diet compared with an omega-6 FA rich diet on the growth of human melanoma in vivo. A similar animal model was used to test the effect of oral TAK-875 on the growth of established melanoma tumors in vivo. DHA has an inhibitory effect on the growth of human melanoma both in vitro and in vivo. Tumors from animals on the omega-3 FA rich diet were 69% smaller in weight (P = 0.005) and 76% smaller in volume compared with tumors from animals on the omega-6 FA rich diet. TAK-875 has an inhibitory effect on the growth of human melanoma both in vitro and in vivo. Tumors from animals treated with TAK-875 were 46% smaller in weight (P = 0.07), 62% smaller in volume (P = 0.03), and grew 77% slower (P = 0.04) compared with the placebo group. DHA and TAK-875 have a profound and selective inhibitory effect on the growth of human melanoma both in vitro and in vivo. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Requirements and ontology for a G protein-coupled receptor oligomerization knowledge base

    NARCIS (Netherlands)

    Skrabanek, L.; Murcia, M.; Bouvier, M.; Devi, L.; George, S.R.; Lohse, M.J.; Milligan, G.; Neubig, R.; Palczewski, K.; Parmentier, M.; Pin, J.P.; Vriend, G.; Javitch, J.A.; Campagne, F.; Filizola, M.

    2007-01-01

    BACKGROUND: G Protein-Coupled Receptors (GPCRs) are a large and diverse family of membrane proteins whose members participate in the regulation of most cellular and physiological processes and therefore represent key pharmacological targets. Although several bioinformatics resources support research

  2. Chronic regulation of colonic epithelial secretory function by activation of G protein-coupled receptors.

    LENUS (Irish Health Repository)

    Toumi, F

    2011-02-01

    Enteric neurotransmitters that act at G protein-coupled receptors (GPCRs) are well known to acutely promote epithelial Cl(-) and fluid secretion. Here we examined if acute GPCR activation might have more long-term consequences for epithelial secretory function.

  3. Repeated pre-treatment with antihistamines suppresses [corrected] transcriptional up-regulations of histamine H(1) receptor and interleukin-4 genes in toluene-2,4-diisocyanate-sensitized rats.

    Science.gov (United States)

    Mizuguchi, Hiroyuki; Hatano, Masaya; Matsushita, Chiyo; Umehara, Hayato; Kuroda, Wakana; Kitamura, Yoshiyuki; Takeda, Noriaki; Fukui, Hiroyuki

    2008-12-01

    Antihistamines are effective for treatment of seasonal nasal allergy. Recently, prophylactic treatment with antihistamines in patients with pollinosis was reported to be more effective when started before the pollen season. The administration with antihistamines from 2 to 6 weeks before onset of the pollen season is recommended for management of allergic rhinitis in Japan. To determine the reason for the effectiveness of prophylactic treatment with antihistamines, the effects of repeated pre-treatment with antihistamines before provocation with toluene 2,4-diisocyanate (TDI) on their nasal allergy-like behavior and up-regulations of histamine H(1) receptors (H1R) and interleukin (IL)-4 mRNAs in their nasal mucosa were examined. Provocation with TDI induced sneezing and up-regulations of H1R and IL-4 mRNAs in the nasal mucosa of TDI-sensitized rats. Repeated pre-treatments with antihistamines including epinastine, olopatadine, or d-chlorpheniramine for 1 to 5 weeks before provocation with TDI suppressed TDI-induced sneezing and the up-regulations of H1R and IL-4 mRNAs in the nasal mucosa more than their administrations once or for 3 days before TDI provocation. Our data indicate that repeated pre-treatment with antihistamines before provocation with TDI is more effective than their single treatment in reducing nasal allergy-like behavior by causing additional suppression of up-regulations of H1R and IL-4 mRNAs in the nasal mucosa.

  4. BIOLUMINISCENCE RESONANCE ENERGY TRANSFER (BRET) METHODS TO STUDY G PROTEIN-COUPLED RECEPTOR - RECEPTOR TYROSINE KINASE HETERORECEPTOR COMPLEXES

    OpenAIRE

    Borroto-Escuela, Dasiel O.; Flajolet, Marc; Agnati, Luigi F.; Greengard, Paul; Fuxe, Kjell

    2013-01-01

    A large body of evidence indicates that G protein-coupled receptors (GPCRs) and Receptor tyrosine kinases (RTKs) can form heteroreceptor complexes. In these complexes, the signalling from each interacting protomer is modulated to produce an integrated and therefore novel response upon agonist(s) activation. In the GPCR-RTK heteroreceptor complexes, GPCRs can activate RTK in the absence of added growth factor through the use of RTK signalling molecules. This integrative phenomenon is reciproca...

  5. 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...

  6. Structure of the full-length glucagon class B G-protein-coupled receptor

    NARCIS (Netherlands)

    Zhang, Haonan; Qiao, Anna; Yang, Dehua; Yang, Linlin; Dai, Antao; de Graaf, C.; Reedtz-Runge, Steffen; Dharmarajan, Venkatasubramanian; Zhang, Hui; Han, Gye Won; Grant, Thomas D.; Sierra, Raymond G.; Weierstall, Uwe; Nelson, Garrett; Liu, Wei; Wu, Yanhong; Ma, Limin; Cai, Xiaoqing; Lin, Guangyao; Wu, Xiaoai; Geng, Zhi; Dong, Yuhui; Song, Gaojie; Griffin, Patrick R.; Lau, Jesper; Cherezov, Vadim; Yang, Huaiyu; Hanson, Michael A.; Stevens, Raymond C.; Zhao, Qiang; Jiang, Hualiang; Wang, Ming Wei; Wu, Beili

    2017-01-01

    The human glucagon receptor, GCGR, belongs to the class B G-protein-coupled receptor family and plays a key role in glucose homeostasis and the pathophysiology of type 2 diabetes. Here we report the 3.0 Å crystal structure of full-length GCGR containing both the extracellular domain and

  7. G-protein coupled progesterone receptors in the plasma membrane of fungus Rhizopus nigricans.

    Science.gov (United States)

    Bavec, A; Slajpah, M; Lenasi, H; Yorko, M; Breskvar, K

    2000-01-01

    We have demonstrated simultaneous existence of progesterone receptors and GTPase activity in the membranes prepared from the filamentous fungus Rhizopus nigricans. The results obtained with pertussis toxin treated fungal mycelium suggest that these receptors do not couple to Gi-Go-proteins and play a role in the induction of steroid hydroxylating enzyme system by steroid substrates in the fungus.

  8. Use of Designer G Protein-Coupled Receptors to Dissect Metabolic Pathways.

    Science.gov (United States)

    Wess, Jürgen

    2016-09-01

    G protein-coupled receptors (GPCRs) regulate virtually all metabolic processes, including glucose and energy homeostasis. Recently, the use of designer GPCRs referred to as designer receptors exclusively activated by designer drug (DREADDs) has made it possible to dissect metabolically relevant GPCR signaling pathways in a temporally and spatially controlled fashion in vivo. Published by Elsevier Ltd.

  9. Histamine poisoning from ingestion of fish or scombroid syndrome.

    Science.gov (United States)

    Tortorella, Vincenzo; Masciari, Peppino; Pezzi, Mario; Mola, Assunta; Tiburzi, Simona Paola; Zinzi, Maria Concetta; Scozzafava, Annamaria; Verre, Mario

    2014-01-01

    The scombroid poisoning is due to the ingestion of poorly preserved fish (especially tuna, sardines, and mackerel) out of the cold chain. Under the influence of the proliferation of gram negative bacteria that occurs for heating, the histidine content in the muscle of the fish is converted into histamine, by the action of the enzyme histidine decarboxylase. If the histamine is ingested in large quantities, it causes an anaphylactoid reaction with a variety of symptoms from moderate to severe to life-threating. We will describe two cases that came under our observation after consuming a meal of bluefin tuna. The diagnosis of scombroid syndrome was made on the basis of the anamnestic data and the clinical one. The rapid resolution of the signs and symptoms after treatment with histamines H1-H2 receptor blockers confirmed the suspected diagnosis.

  10. Histamine Poisoning from Ingestion of Fish or Scombroid Syndrome

    Directory of Open Access Journals (Sweden)

    Vincenzo Tortorella

    2014-01-01

    Full Text Available The scombroid poisoning is due to the ingestion of poorly preserved fish (especially tuna, sardines, and mackerel out of the cold chain. Under the influence of the proliferation of gram negative bacteria that occurs for heating, the histidine content in the muscle of the fish is converted into histamine, by the action of the enzyme histidine decarboxylase. If the histamine is ingested in large quantities, it causes an anaphylactoid reaction with a variety of symptoms from moderate to severe to life-threating. We will describe two cases that came under our observation after consuming a meal of bluefin tuna. The diagnosis of scombroid syndrome was made on the basis of the anamnestic data and the clinical one. The rapid resolution of the signs and symptoms after treatment with histamines H1-H2 receptor blockers confirmed the suspected diagnosis.

  11. A Molecular Mechanism for Sequential Activation of a G Protein-Coupled Receptor

    DEFF Research Database (Denmark)

    Grundmann, Manuel; Tikhonova, Irina G; Hudson, Brian D

    2016-01-01

    Ligands targeting G protein-coupled receptors (GPCRs) are currently classified as either orthosteric, allosteric, or dualsteric/bitopic. Here, we introduce a new pharmacological concept for GPCR functional modulation: sequential receptor activation. A hallmark feature of this is a stepwise ligand...... and pharmacological perturbations along with computational methods, and propose a kinetic model applicable to the analysis of sequential receptor activation. We envision this form of dynamic agonism as a common principle of nature to spatiotemporally encode cellular information....

  12. Histamine 50-Skin-Prick Test: A Tool to Diagnose Histamine Intolerance

    OpenAIRE

    Lukas Kofler; Hanno Ulmer; Heinz Kofler

    2011-01-01

    Background. Histamine intolerance results from an imbalance between histamine intake and degradation. In healthy persons, dietary histamine can be sufficiently metabolized by amine oxidases, whereas persons with low amine oxidase activity are at risk of histamine toxicity. Diamine oxidase (DAO) is the key enzyme in degradation. Histamine elicits a wide range of effects. Histamine intolerance displays symptoms, such as rhinitis, headache, gastrointestinal symptoms, palpitations, urticaria and ...

  13. S-Nitrosothiols modulate G protein-coupled receptor signaling in a reversible and highly receptor-specific manner

    Directory of Open Access Journals (Sweden)

    Mönkkönen Kati S

    2005-04-01

    Full Text Available Abstract Background Recent studies indicate that the G protein-coupled receptor (GPCR signaling machinery can serve as a direct target of reactive oxygen species, including nitric oxide (NO and S-nitrosothiols (RSNOs. To gain a broader view into the way that receptor-dependent G protein activation – an early step in signal transduction – might be affected by RSNOs, we have studied several receptors coupling to the Gi family of G proteins in their native cellular environment using the powerful functional approach of [35S]GTPγS autoradiography with brain cryostat sections in combination with classical G protein activation assays. Results We demonstrate that RSNOs, like S-nitrosoglutathione (GSNO and S-nitrosocysteine (CysNO, can modulate GPCR signaling via reversible, thiol-sensitive mechanisms probably involving S-nitrosylation. RSNOs are capable of very targeted regulation, as they potentiate the signaling of some receptors (exemplified by the M2/M4 muscarinic cholinergic receptors, inhibit others (P2Y12 purinergic, LPA1lysophosphatidic acid, and cannabinoid CB1 receptors, but may only marginally affect signaling of others, such as adenosine A1, μ-opioid, and opiate related receptors. Amplification of M2/M4 muscarinic responses is explained by an accelerated rate of guanine nucleotide exchange, as well as an increased number of high-affinity [35S]GTPγS binding sites available for the agonist-activated receptor. GSNO amplified human M4 receptor signaling also under heterologous expression in CHO cells, but the effect diminished with increasing constitutive receptor activity. RSNOs markedly inhibited P2Y12 receptor signaling in native tissues (rat brain and human platelets, but failed to affect human P2Y12 receptor signaling under heterologous expression in CHO cells, indicating that the native cellular signaling partners, rather than the P2Y12 receptor protein, act as a molecular target for this action. Conclusion These in vitro studies

  14. Definition of the G protein-coupled receptor transmembrane bundle binding pocket and calculation of receptor similarities for drug design

    DEFF Research Database (Denmark)

    Gloriam, David Erik Immanuel; Foord, Steven M; Blaney, Frank E

    2009-01-01

    Recent advances in structural biology for G-protein-coupled receptors (GPCRs) have provided new opportunities to improve the definition of the transmembrane binding pocket. Here a reference set of 44 residue positions accessible for ligand binding was defined through detailed analysis of all...... currently available crystal structures. This was used to characterize pharmacological relationships of Family A/Rhodopsin family GPCRs, minimizing evolutionary influence from parts of the receptor that do not generally affect ligand binding. The resultant dendogram tended to group receptors according...... the pharmacology/selectivity profile of ligands at Family A GPCRs. This has wide applicability to GPCR drug design problems across many disease areas....

  15. G Protein-Coupled Receptors: Extranuclear Mediators for the Non-Genomic Actions of Steroids

    Directory of Open Access Journals (Sweden)

    Chen Wang

    2014-09-01

    Full Text Available Steroids hormones possess two distinct actions, a delayed genomic effect and a rapid non-genomic effect. Rapid steroid-triggered signaling is mediated by specific receptors localized most often to the plasma membrane. The nature of these receptors is of great interest and accumulated data suggest that G protein-coupled receptors (GPCRs are appealing candidates. Increasing evidence regarding the interaction between steroids and specific membrane proteins, as well as the involvement of G protein and corresponding downstream signaling, have led to identification of physiologically relevant GPCRs as steroid extranuclear receptors. Examples include G protein-coupled receptor 30 (GPR30 for estrogen, membrane progestin receptor for progesterone, G protein-coupled receptor family C group 6 member A (GPRC6A and zinc transporter member 9 (ZIP9 for androgen, and trace amine associated receptor 1 (TAAR1 for thyroid hormone. These receptor-mediated biological effects have been extended to reproductive development, cardiovascular function, neuroendocrinology and cancer pathophysiology. However, although great progress have been achieved, there are still important questions that need to be answered, including the identities of GPCRs responsible for the remaining steroids (e.g., glucocorticoid, the structural basis of steroids and GPCRs’ interaction and the integration of extranuclear and nuclear signaling to the final physiological function. Here, we reviewed the several significant developments in this field and highlighted a hypothesis that attempts to explain the general interaction between steroids and GPCRs.

  16. Effects of histamine and antihistamines on the kinetics of carbon dioxide in the rat

    Energy Technology Data Exchange (ETDEWEB)

    Russell, J.C.; Chambers, M.M.

    1981-01-01

    We have investigated the effects of chlorpheniramine (an H1 histamine inhibitor) and metiamide (an H2 inhibitor) on response to 14C pulse-labeling of carbon dioxide in the rat in the presence and absence of histamine. Neither chlorpheniramine nor metiamide alone had any effect upon the gastric venous/arterial ratio (VG/A) or the peripheral venous/arterial ratio (Vp/A). As in the case with no drug present, Vp/A rose with time following pulse-labeling to a value of 1.15-1.20. The presence of a preexisting steady-state infusion of histamine caused no changes in the ratios in the presence or absence of the inhibitors. The inhibitors did completely abolish the oscillations of both VG/A and Vp/A caused by initiation of histamine infusion coincident with the pulse-labeling. The results suggest that the histamine effects are largely mediated through H1 receptors.

  17. The role of histamine in the regulation of the viability, proliferation and transforming growth factor β1 secretion of rat wound fibroblasts.

    Science.gov (United States)

    Wolak, Monika; Bojanowska, Ewa; Staszewska, Teresa; Ciosek, Joanna; Juszczak, Marlena; Drobnik, Jacek

    2017-04-01

    Inflammation mediators play a regulatory role in repair processes. The study will examine the influence of histamine on wound fibroblast metabolic activity, viability, proliferation, and TGFβ1 secretion. The study also will identify the histamine receptor involved in regulation of the tested repair processes. Fibroblasts were obtained from the granulation tissue of wounds or intact dermis of rats. The MTT and BrdU assays were used to examine the effect of histamine (10-8M-10-4M) on the viability and metabolic activity of fibroblasts, and on their proliferative capacity. The influence of histamine receptor antagonists (i.e., ketotifen, ranitidine, ciproxifan and JNJ7777120) and agonists (2-pyridylethlamine dihydrochloride, amthamine dihydrobromide) was also investigated. The TGFβ1 and histamine receptors H1 were evaluated by enzyme-linked immunosorbent assay. Histamine significantly increased granulation tissue fibroblast viability and metabolic activity at 10-8 and 10-6M but did not change their proliferative activity. Only the blockade of the H1 receptor removed this effect of histamine. H1 receptor agonist (2-pyridylethlamine dihydrochloride) increased cell viability, thereby mimicking histamine action. Both Histamine (10-4M) and 2-pyridylethlamine dihydrochloride increased TGFβ1 concentration in cell culture medium. However, ketotifen blocked histamine-induced augmentation of TGFβ1. H1 receptor expression on wound fibroblasts was confirmed. The regulatory influence of histamine on wound fibroblast function (viability/metabolic activity or secretion of TGFβ1) is dependent on H1 receptor stimulation. Contrary to wound fibroblasts, these cells express a very low level of H1 receptors when isolated from intact dermis and histamine is unable to modify their metabolic activity. Copyright © 2016. Published by Elsevier Urban & Partner Sp. z o.o.

  18. Validation of basophil histamine release against the autologous serum skin test and outcome of serum-induced basophil histamine release studies in a large population of chronic urticaria patients

    DEFF Research Database (Denmark)

    Platzer, M H; Grattan, C E H; Poulsen, Lars K.

    2005-01-01

    the immunoglobulin E (IgE) or the high affinity IgE receptor (FcepsilonRI) and serum-induced histamine release (HR) from basophils and mast cells. We have examined the correlation between the ASST and a new basophil histamine-releasing assay (the HR-Urtikaria test) in a group of well-characterized CU patients...

  19. Molecular identification of a Drosophila G protein-coupled receptor specific for crustacean cardioactive peptide

    DEFF Research Database (Denmark)

    Cazzamali, Giuseppe; Hauser, Frank; Kobberup, Sune

    2003-01-01

    The Drosophila Genome Project website (www.flybase.org) contains the sequence of an annotated gene (CG6111) expected to code for a G protein-coupled receptor. We have cloned this receptor and found that its gene was not correctly predicted, because an annotated neighbouring gene (CG14547) was also...... part of the receptor gene. DNA corresponding to the corrected gene CG6111 was expressed in Chinese hamster ovary cells, where it was found to code for a receptor that could be activated by low concentrations of crustacean cardioactive peptide, which is a neuropeptide also known to occur in Drosophila...... and other insects (EC(50), 5.4 x 10(-10)M). Other known Drosophila neuropeptides, such as adipokinetic hormone, did not activate the receptor. The receptor is expressed in all developmental stages from Drosophila, but only very weakly in larvae. In adult flies, the receptor is mainly expressed in the head...

  20. Dimers of G-Protein Coupled Receptors as Versatile Storage and Response Units

    Directory of Open Access Journals (Sweden)

    Michael S. Parker

    2014-03-01

    Full Text Available The status and use of transmembrane, extracellular and intracellular domains in oligomerization of heptahelical G-protein coupled receptors (GPCRs are reviewed and for transmembrane assemblies also supplemented by new experimental evidence. The transmembrane-linked GPCR oligomers typically have as the minimal unit an asymmetric ~180 kDa pentamer consisting of receptor homodimer or heterodimer and a G-protein αβγ subunit heterotrimer. With neuropeptide Y (NPY receptors, this assembly is converted to ~90 kDa receptor monomer-Gα complex by receptor and Gα agonists, and dimers/heteropentamers are depleted by neutralization of Gαi subunits by pertussis toxin. Employing gradient centrifugation, quantification and other characterization of GPCR dimers at the level of physically isolated and identified heteropentamers is feasible with labeled agonists that do not dissociate upon solubilization. This is demonstrated with three neuropeptide Y (NPY receptors and could apply to many receptors that use large peptidic agonists.

  1. Mast cell chymase potentiates histamine-induced wheal formation in the skin of ragweed-allergic dogs.

    Science.gov (United States)

    Rubinstein, I; Nadel, J A; Graf, P D; Caughey, G H

    1990-01-01

    Skin mast cells release the neutral protease chymase along with histamine during degranulation. To test the hypothesis that chymase modulates histamine-induced plasma extravasation, we measured wheal formation following intradermal injection of purified mast cell chymase and histamine into the skin of ragweed-allergic dogs. We found that chymase greatly augments histamine-induced wheal formation. The magnitude of the potentiating effect increases with increasing doses of chymase and becomes maximal approximately 30 min after administration. Injection of chymase without histamine does not evoke wheal formation. The chymase potentiation of histamine-induced skin responses is prevented completely by pretreatment with the H1-receptor antagonist pyrilamine, and is prevented by inactivation of chymase with soybean trypsin inhibitor, suggesting that both histamine and preserved catalytic activity are required for the effects of chymase. To examine the effects of histamine and chymase released in situ in further experiments, we measured wheal size following local degranulation of mast cells by intradermal injection of ragweed antigen or compound 48/80. We found that pretreatment with either soybean trypsin inhibitor or pyrilamine markedly reduces ragweed antigen- or 48/80-induced wheal formation, supporting the results obtained by injection of exogenous chymase and histamine. These findings suggest a novel and important proinflammatory role for chymase in modulating the effects of histamine on vascular permeability during mast cell activation. PMID:2384602

  2. Neomycin inhibits histamine and thapsigargin mediated Ca2+ DDT1 MF-2 cells independent of phospholipase C activation

    NARCIS (Netherlands)

    Sipma, H; VanderZee, L; DenHertog, A; Nelemans, A

    1996-01-01

    The histamine H-1 receptor mediated increase in cytoplasmic Ca2+ ([Ca2+](i)) was measured in the presence of the known phospholipase C (PLC) inhibitor, neomycin. Neomycin (1 mM) inhibited the histamine (100 mu M) induced rise in [Ca2+](i) to the same extent as observed after blocking Ca2+ entry with

  3. Molecular basis for activation of G protein-coupled receptor kinases

    Energy Technology Data Exchange (ETDEWEB)

    Boguth, Cassandra A.; Singh, Puja; Huang, Chih-chin; Tesmer, John J.G. (Michigan)

    2012-03-16

    G protein-coupled receptor (GPCR) kinases (GRKs) selectively recognize and are allosterically regulated by activated GPCRs, but the molecular basis for this interaction is not understood. Herein, we report crystal structures of GRK6 in which regions known to be critical for receptor phosphorylation have coalesced to stabilize the kinase domain in a closed state and to form a likely receptor docking site. The crux of this docking site is an extended N-terminal helix that bridges the large and small lobes of the kinase domain and lies adjacent to a basic surface of the protein proposed to bind anionic phospholipids. Mutation of exposed, hydrophobic residues in the N-terminal helix selectively inhibits receptor, but not peptide phosphorylation, suggesting that these residues interact directly with GPCRs. Our structural and biochemical results thus provide an explanation for how receptor recognition, phospholipid binding, and kinase activation are intimately coupled in GRKs.

  4. Enhancement of ionizing radiation response by histamine in vitro and in vivo in human breast cancer

    Science.gov (United States)

    Martinel Lamas, Diego J; Cortina, Jorge E; Ventura, Clara; Sterle, Helena A; Valli, Eduardo; Balestrasse, Karina B; Blanco, Horacio; Cremaschi, Graciela A; Rivera, Elena S; Medina, Vanina A

    2015-01-01

    The radioprotective potential of histamine on healthy tissue has been previously demonstrated. The aims of this work were to investigate the combinatorial effect of histamine or its receptor ligands and gamma radiation in vitro on the radiobiological response of 2 breast cancer cell lines (MDA-MB-231 and MCF-7), to explore the potential molecular mechanisms of the radiosensitizing action and to evaluate the histamine-induced radiosensitization in vivo in a triple negative breast cancer model. Results indicate that histamine significantly increased the radiosensitivity of MDA-MB-231 and MCF-7 cells. This effect was mimicked by the H1R agonist 2-(3-(trifluoromethyl)phenyl)histamine and the H4R agonists (Clobenpropit and VUF8430) in MDA-MB-231 and MCF-7 cells, respectively. Histamine and its agonists enhanced radiation-induced oxidative DNA damage, DNA double-strand breaks, apoptosis and senescence. These effects were associated with increased production of reactive oxygen species, which correlated with the inhibition of catalase, glutathione peroxidase and superoxide dismutase activities in MDA-MB-231 cells. Histamine was able also to potentiate in vivo the anti-tumoral effect of radiation, increasing the exponential tumor doubling time. We conclude that histamine increased radiation response of breast cancer cells, suggesting that it could be used as a potential adjuvant to enhance the efficacy of radiotherapy. PMID:25482934

  5. H1 but not H2 histamine antagonist receptors mediate anxiety-related behaviors and emotional memory deficit in mice subjected to elevated plus-maze testing

    Directory of Open Access Journals (Sweden)

    K.R. Serafim

    2013-05-01

    Full Text Available This study investigated the role of H1 and H2 receptors in anxiety and the retrieval of emotional memory using a Trial 1/Trial 2 (T1/T2 protocol in an elevated plus-maze (EPM. Tests were performed on 2 consecutive days, designated T1 and T2. Before T1, the mice received intraperitoneal injections of saline (SAL, 20 mg/kg zolantidine (ZOL, an H2 receptor antagonist, or 8.0 or 16 mg/kg chlorpheniramine (CPA, an H1 receptor antagonist. After 40 min, they were subjected to the EPM test. In T2 (24 h later, each group was subdivided into two additional groups, and the animals from each group were re-injected with SAL or one of the drugs. In T1, the Student t-test showed no difference between the SAL and ZOL or 8 mg/kg CPA groups with respect to the percentages of open arm entries (%OAE and open arm time (%OAT. However, administration of CPA at the highest dose of 16 mg/kg decreased %OAE and %OAT, but not locomotor activity, indicating anxiogenic-like behavior. Emotional memory, as revealed by a reduction in open arm exploration between the two trials, was observed in all experimental groups, indicating that ZOL and 8 mg/kg CPA did not affect emotional memory, whereas CPA at the highest dose affected acquisition and consolidation, but not retrieval of memory. Taken together, these results suggest that H1 receptor, but not H2, is implicated in anxiety-like behavior and in emotional memory acquisition and consolidation deficits in mice subjected to EPM testing.

  6. Purification of family B G protein-coupled receptors using nanodiscs: Application to human glucagon-like peptide-1 receptor.

    Directory of Open Access Journals (Sweden)

    Yingying Cai

    Full Text Available Family B G protein-coupled receptors (GPCRs play vital roles in hormone-regulated homeostasis. They are drug targets for metabolic diseases, including type 2 diabetes and osteoporosis. Despite their importance, the signaling mechanisms for family B GPCRs at the molecular level remain largely unexplored due to the challenges in purification of functional receptors in sufficient amount for biophysical characterization. Here, we purified the family B GPCR human glucagon-like peptide-1 (GLP-1 receptor (GLP1R, whose agonists, e.g. exendin-4, are used for the treatment of type 2 diabetes mellitus. The receptor was expressed in HEK293S GnTl- cells using our recently developed protocol. The protocol incorporates the receptor into the native-like lipid environment of reconstituted high density lipoprotein (rHDL particles, also known as nanodiscs, immediately after the membrane solubilization step followed by chromatographic purification, minimizing detergent contact with the target receptor to reduce denaturation and prolonging stabilization of receptor in lipid bilayers without extra steps of reconstitution. This method yielded purified GLP1R in nanodiscs that could bind to GLP-1 and exendin-4 and activate Gs protein. This nanodisc purification method can potentially be a general strategy to routinely obtain purified family B GPCRs in the 10s of microgram amounts useful for spectroscopic analysis of receptor functions and activation mechanisms.

  7. The anti-anaphylactic and histamine-releasing properties of the antihistamines. Their effect on the mast cells

    Science.gov (United States)

    Mota, I.; Da Silva, W. Dias

    1960-01-01

    It has been shown that, depending upon their concentration, antihistamines act in three different ways: (a) by competitive inhibition of histamine as already known; (b) by destroying mast cells and releasing histamine; and (c) by preventing mast cell damage and histamine release in anaphylaxis. Furthermore, antihistamines potentiated mast cell damage and histamine release by compound 48/80, when acting on guinea-pig tissues, and inhibited these same phenomena when acting on rat tissues. It is concluded that the effect of antihistamines in anaphylaxis is possibly due both to their competitive inhibition of histamine on smooth muscle receptors and to their inhibition of mast cell damage and histamine release by antigen. PMID:13773171

  8. Construction of covalently coupled, concatameric dimers of 7TM receptors

    DEFF Research Database (Denmark)

    Terpager, Marie; Scholl, D Jason; Kubale, Valentina

    2009-01-01

    7TM receptors are easily fused to proteins such as G proteins and arrestin but because of the fact that their terminals are found on each side of the membrane they cannot be joined directly in covalent dimers. Here, we use an artificial connector comprising a transmembrane helix composed of Leu...

  9. Membrane cholesterol access into a G-protein-coupled receptor

    Czech Academy of Sciences Publication Activity Database

    Guixa-González, R.; Albasanz, J. L.; Rodriguez-Espigares, I.; Pastor, M.; Sanz, F.; Martí-Solano, M.; Manna, M.; Martinez-Seara, Hector; Hildebrand, P. W.; Martín, M.; Selent, J.

    2017-01-01

    Roč. 8, Feb 21 (2017), č. článku 14505. ISSN 2041-1723 Institutional support: RVO:61388963 Keywords : postmortem orbitofrontal cortex * A(2A) adenosine receptor * molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 12.124, year: 2016 https://www.nature.com/articles/ncomms14505

  10. Determination of histamine in fish by Surface Enhanced Raman Spectroscopy using silver colloid SERS substrates.

    Science.gov (United States)

    Janči, Tibor; Valinger, Davor; Gajdoš Kljusurić, Jasenka; Mikac, Lara; Vidaček, Sanja; Ivanda, Mile

    2017-06-01

    This study was focused on development of a rapid and sensitive method for histamine determination in fish based on Surface Enhanced Raman Spectroscopy (SERS) using simple and widely available silver colloid SERS substrate. Extraction of histamine with 0.4M perchloric acid and purification with 1-butanol significantly shortened sample preparation (30min) and provided clear SERS spectra with characteristic Raman bands of histamine. Principal component analysis effectively distinguished SERS spectra of fish samples with different histamine content. Partial least square (PLS) regression models confirmed reliability of detection and spectral analysis of histamine with SERS. In histamine concentration range 0-200mgkg-1, significant in legislative and fish quality control aspects, PLS regression model based on spectral range 1139.9-1643.7cm-1 showed linear trend with R2pred=0.962, RPD=7.250. Presented protocol for histamine extraction and purification followed by SERS analysis coupled with chemometric approach, enabled development of rapid and inexpensive method for histamine determination in fish. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. A New Molecular Mechanism To Engineer Protean Agonism at a G Protein-Coupled Receptor.

    Science.gov (United States)

    De Min, Anna; Matera, Carlo; Bock, Andreas; Holze, Janine; Kloeckner, Jessica; Muth, Mathias; Traenkle, Christian; De Amici, Marco; Kenakin, Terry; Holzgrabe, Ulrike; Dallanoce, Clelia; Kostenis, Evi; Mohr, Klaus; Schrage, Ramona

    2017-04-01

    Protean agonists are of great pharmacological interest as their behavior may change in magnitude and direction depending on the constitutive activity of a receptor. Yet, this intriguing phenomenon has been poorly described and understood, due to the lack of stable experimental systems and design strategies. In this study, we overcome both limitations: First, we demonstrate that modulation of the ionic strength in a defined experimental set-up allows for analysis of G protein-coupled receptor activation in the absence and presence of a specific amount of spontaneous receptor activity using the muscarinic M2 acetylcholine receptor as a model. Second, we employ this assay system to show that a dualsteric design principle, that is, molecular probes, carrying two pharmacophores to simultaneously adopt orthosteric and allosteric topography within a G protein-coupled receptor, may represent a novel approach to achieve protean agonism. We pinpoint three molecular requirements within dualsteric compounds that elicit protean agonism at the muscarinic M2 acetylcholine receptor. Using radioligand-binding and functional assays, we posit that dynamic ligand binding may be the mechanism underlying protean agonism of dualsteric ligands. Our findings provide both new mechanistic insights into the still enigmatic phenomenon of protean agonism and a rationale for the design of such compounds for a G protein-coupled receptor. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

  12. Functional selectivity of G-protein-coupled receptors: from recombinant systems to native human cells.

    Science.gov (United States)

    Seifert, Roland

    2013-10-01

    In the mid 1990s, it was assumed that a two-state model, postulating an inactive (R) state and an active (R*) state provides the molecular basis for GPCR activation. However, it became clear that this model could not accommodate many experimental observations. Accordingly, the two-state model was superseded by a multi-state model according to which any given ligand stabilizes a unique receptor conformation with distinct capabilities of activating down-stream G-proteins and β-arrestin. Much of this research was conducted with the β2-adrenoceptor in recombinant systems. At the molecular level, there is now no doubt anymore that ligand-specific receptor conformations, also referred to as functional selectivity, exist. This concept holds great potential for drug discovery in terms of developing drugs with higher selectivity for specific cells and/or cell functions and fewer side effects. A major challenge is the analysis for functional selectivity in native cells. Here, I discuss our current knowledge on functional selectivity of three representative GPCRs, the β2-adrenoceptor and the histamine H2- and H4-receptors, in recombinant systems and native human cells. Studies with human neutrophils and eosinophils support the concept of functional selectivity. A major strategy for the analysis of functional selectivity in native cells is to generate complete concentration/response curves with a large set of structurally diverse ligands for multiple parameters. Next, correlations of potencies and efficacies are analyzed, and deviations of the correlations from linearity are indicative for functional selectivity. Additionally, pharmacological inhibitors are used to dissect cell functions from each other. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Effects of microinjection of histamine into the anterior cingulate cortex on pain-related behaviors induced by formalin in rats.

    Science.gov (United States)

    Hamzeh-Gooshchi, Nasrin; Tamaddonfard, Esmaeal; Farshid, Amir Abbas

    2015-06-01

    The present study was aimed to investigate the effects of microinjection of histamine and its H1, H2 and H3 receptor antagonists, mepyramine, ranitidine and thioperamide, respectively, into the anterior cingulate cortex (ACC) on pain-related behaviors induced by formalin in rats. Two stainless steel guide canulas were bilaterally implanted into the ACC of anaesthetized rats. For induction of pain, intraplantar (ipl) injection of a 2.5% formalin solution was performed. The duration of paw licking/biting and the number of paw flinching were recorded in 5 min blocks for 60 min. Locomotor activity was assessed using an open-field test. Formalin produced a marked biphasic pattern of pain. Histamine reduced the second phases of paw licking/biting and flinching. Mepyramine (2 μg/side) prevented the suppressive effect of histamine (1 μg/side) on second phase of pain, but at a dose of 8 μg/side it did not inhibit the suppressive effects of 4 μg/side of histamine. Ranitidine at doses of 2 and 8 μg/side prevented histamine (1 and 4 μg/side)-induced antinociception. Thioperamide not only suppressed the second phases of pain, but also increased the suppressive effect of histamine. Naloxone prevented suppressive effects of histamine and thioperamide on pain. Mepyramine (8 μg/side) suppressed locomotor activity. The results of the present study showed pain suppressing effects for histamine. Histamine H2 and H3, and to a lesser extent, H1 receptors might be involved in histamine-induced antinociception. Opioid receptors might be involved in suppressive effects of histamine and thioperamide. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  14. Characterization of umami receptor and coupling G protein in mouse taste cells.

    Science.gov (United States)

    Narukawa, Masataka; Kitagawa-Iseki, Keiko; Oike, Hideaki; Abe, Keiko; Mori, Tomohiko; Hayashi, Yukako

    2008-08-06

    Taste receptor cells (TRCs) express multiple umami receptors. We performed physiological investigations to determine whether umami-responding cells in taste buds possess G protein-coupled receptors and to determine what type of G proteins exist if any. To clarify the components that participate in intracellular umami signal transduction in mouse, we recorded the activation of TRCs. TRCs treated with the G protein inhibitor GDP-beta-S lost umami-induced inward currents. Treatment with the Galphai inhibitor, pertussis toxin, did not increase the intracellular Ca2+ level in many TRCs. Immunohistochemical analysis revealed that a subset of TRCs responding to umami stimuli expressed alpha-gustducin. Thus, we demonstrated that umami stimuli were received by G protein-coupled receptors that function together with some of the Galphai family members.

  15. Broad-spectrum L-amino acid sensing by class 3 G-protein-coupled receptors.

    Science.gov (United States)

    Conigrave, Arthur D; Hampson, David R

    2006-12-01

    The sensing of nutrients is essential to the control of growth and metabolism. Although the sensing mechanisms responsible for the detection and coordination of metabolic responses to some nutrients, most notably glucose, are well understood, the molecular basis of amino acid sensing by cells and tissues is only now emerging. In this article, we consider evidence that some members of G-protein-coupled receptor class 3 are broad-spectrum amino acid sensors that couple changes in extracellular amino acid levels to the activation of intracellular signaling pathways. In particular, we consider both the molecular basis of specific and broad-spectrum amino acid sensing by different members of class 3 and the physiological significance of broad spectrum amino acid sensing by the extracellular calcium-sensing receptor, heterodimeric taste receptors and the recently "deorphanized" receptor GPRC6A and its goldfish homolog, the 5.24 chemoreceptor.

  16. Aspirin augments IgE-mediated histamine release from human peripheral basophils via Syk kinase activation.

    Science.gov (United States)

    Matsuo, Hiroaki; Yokooji, Tomoharu; Morita, Hironobu; Ooi, Mina; Urata, Kana; Ishii, Kaori; Takahagi, Shunsuke; Yanase, Yuhki; Hiragun, Takaaki; Mihara, Shoji; Hide, Michihiro

    2013-12-01

    Non-steroidal anti-inflammatory drugs (NSAIDs), especially aspirin, and food additives (FAs) may exacerbate allergic symptoms in patients with chronic idiopathic urticaria and food-dependent exercise-induced anaphylaxis (FDEIA). Augmentation of histamine release from human mast cells and basophils by those substances is speculated to be the cause of exacerbated allergic symptoms. We sought to investigate the mechanism of action of aspirin on IgE-mediated histamine release. The effects of NSAIDs, FAs or cyclooxygenase (COX) inhibitors on histamine release from human basophils concentrated by gravity separation were evaluated. Benzoate and tartrazine, which have no COX inhibitory activity, augmented histamine release from basophils similar to aspirin. In contrast, ibuprofen, meloxicam, FR122047 and NS-398, which have COX inhibitory activity, did not affect histamine release. These results indicate that the augmentation of histamine release by aspirin is not due to COX inhibition. It was observed that aspirin augmented histamine release from human basophils only when specifically activated by anti-IgE antibodies, but not by A23187 or formyl-methionyl-leucyl-phenylalanine. When the IgE receptor signaling pathway was activated, aspirin increased the phosphorylation of Syk. Moreover, patients with chronic urticaria and FDEIA tended to be more sensitive to aspirin as regards the augmentation of histamine release, compared with healthy controls. Aspirin enhanced histamine release from basophils via increased Syk kinase activation, and that the augmentation of histamine release by NSAIDs or FAs may be one possible cause of worsening symptoms in patients with chronic urticaria and FDEIA.

  17. Co-Effect of Histamine on Ca2+-Dependent Signaling Pathways in Rat Conjunctival Goblet Cells

    Science.gov (United States)

    Li, Dayu; Carozza, Richard B.; Shatos, Marie A.; Hodges, Robin R.; Dartt, Darlene A.

    2012-01-01

    Purpose. The purpose of this study was to determine the Ca2+-dependent cellular signaling pathways used by histamine to stimulate conjunctival goblet cell secretion. Methods. Cultured rat goblet cells were grown in RPMI 1640. Goblet cell secretion of high molecular weight glycoconjugates was measured by an enzyme-linked lectin assay. Intracellular [Ca2+] ([Ca2+]i) was measured by loading cultured cells with the Ca2+ sensitive dye fura-2. The level of [Ca2+]i was measured using fluorescence microscopy. Extracellular regulated kinase (ERK) 2 was depleted using small interfering RNA (siRNA). Results. Histamine-stimulated conjunctival goblet cell secretion of high molecular weight glycoproteins was blocked by removal of extracellular Ca2+ and depletion of ERK2 by siRNA. Histamine increase in [Ca2+]i was desensitized by repeated addition of agonist and blocked by a phospholipase C antagonist. Histamine at higher doses increased [Ca2+]i by stimulating influx of extracellular Ca2+, but at a lower dose released Ca2+ from intracellular stores. Activation of each histamine receptor subtype (H1–H4) increased [Ca2+]i and histamine stimulation was blocked by antagonists of each receptor subtype. The H2 receptor subtype increase in [Ca2+]i was cAMP dependent. Conclusions. We conclude that histamine activates phospholipase C to release intracellular Ca2+ that induces the influx of extracellular Ca2+ and activates ERK1/2 to stimulate conjunctival goblet cell mucous secretion, and that activation of all four histamine receptor subtypes can increase [Ca2+]i. PMID:22956601

  18. Evidence of a broad histamine footprint on the human exercise transcriptome.

    Science.gov (United States)

    Romero, Steven A; Hocker, Austin D; Mangum, Joshua E; Luttrell, Meredith J; Turnbull, Douglas W; Struck, Adam J; Ely, Matthew R; Sieck, Dylan C; Dreyer, Hans C; Halliwill, John R

    2016-09-01

    Histamine is a primordial signalling molecule, capable of activating cells in an autocrine or paracrine fashion via specific cell surface receptors, in a variety of pathways that probably predate its more recent role in innate and adaptive immunity. Although histamine is normally associated with pathological conditions or allergic and anaphylactic reactions, it may contribute beneficially to the normal changes that occur within skeletal muscle during the recovery from exercise. We show that the human response to exercise includes an altered expression of thousands of protein-coding genes, and much of this response appears to be driven by histamine. Histamine may be an important molecular transducer contributing to many of the adaptations that accompany chronic exercise training. Histamine is a primordial signalling molecule, capable of activating cells in an autocrine or paracrine fashion via specific cell surface receptors. In humans, aerobic exercise is followed by a post-exercise activation of histamine H1 and H2 receptors localized to the previously exercised muscle. This could trigger a broad range of cellular adaptations in response to exercise. Thus, we exploited RNA sequencing to explore the effects of H1 and H2 receptor blockade on the exercise transcriptome in human skeletal muscle tissue harvested from the vastus lateralis. We found that exercise exerts a profound influence on the human transcriptome, causing the differential expression of more than 3000 protein-coding genes. The influence of histamine blockade post-exercise was notable for 795 genes that were differentially expressed between the control and blockade condition, which represents >25% of the number responding to exercise. The broad histamine footprint on the human exercise transcriptome crosses many cellular functions, including inflammation, vascular function, metabolism, and cellular maintenance. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

  19. G protein-coupled receptor systems and their lipid environment in health disorders during aging

    OpenAIRE

    Alemany, Regina; Perona, Javier S.; Sánchez-Dominguez, José M.; Montero, Emilio; Cañizares, Julio; Bressani, Ricardo; Escribá, Pablo V.; Ruiz-Gutierrez, Valentina

    2007-01-01

    Cells, tissues and organs undergo phenotypic changes and deteriorate as they age. Cell growth arrest and hyporesponsiveness to extrinsic stimuli are all hallmarks of senescent cells. Most such external stimuli received by a cell are processed by two different cell membrane systems: receptor tyrosine kinases (RTKs) and G protein-coupled receptors (GPCRs). GPCRs form the largest gene family in the human genome and they are involved in most relevant physiological functions. Given the changes obs...

  20. Biophysical approaches to G protein-coupled receptors: Structure, function and dynamics

    Science.gov (United States)

    Chollet, André; Turcatti, Gerardo

    1999-05-01

    G protein-coupled receptors (GPCR) represent a large family of drug targets for which there is no high-resolution structural information. In order to understand the mechanisms of ligand recognition and receptor activation, there is a strong need for novel biophysical methods. In this Perspective we provide an overview of recent experimental approaches used to explore the molecular architecture and dynamics of GPCR and their interactions with ligands and G proteins using biophysical, non-crystallographic, methods.

  1. Molecular evolution of a chordate specific family of G protein-coupled receptors

    Directory of Open Access Journals (Sweden)

    Leese Florian

    2011-08-01

    Full Text Available Abstract Background Chordate evolution is a history of innovations that is marked by physical and behavioral specializations, which led to the development of a variety of forms from a single ancestral group. Among other important characteristics, vertebrates obtained a well developed brain, anterior sensory structures, a closed circulatory system and gills or lungs as blood oxygenation systems. The duplication of pre-existing genes had profound evolutionary implications for the developmental complexity in vertebrates, since mutations modifying the function of a duplicated protein can lead to novel functions, improving the evolutionary success. Results We analyzed here the evolution of the GPRC5 family of G protein-coupled receptors by comprehensive similarity searches and found that the receptors are only present in chordates and that the size of the receptor family expanded, likely due to genome duplication events in the early history of vertebrate evolution. We propose that a single GPRC5 receptor coding gene originated in a stem chordate ancestor and gave rise by duplication events to a gene family comprising three receptor types (GPRC5A-C in vertebrates, and a fourth homologue present only in mammals (GPRC5D. Additional duplications of GPRC5B and GPRC5C sequences occurred in teleost fishes. The finding that the expression patterns of the receptors are evolutionarily conserved indicates an important biological function of these receptors. Moreover, we found that expression of GPRC5B is regulated by vitamin A in vivo, confirming previous findings that linked receptor expression to retinoic acid levels in tumor cell lines and strengthening the link between the receptor expression and the development of a complex nervous system in chordates, known to be dependent on retinoic acid signaling. Conclusions GPRC5 receptors, a class of G protein-coupled receptors with unique sequence characteristics, may represent a molecular novelty that helped non

  2. Receptor oligomerization in family B1 of G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Roed, Sarah Norklit; Ørgaard, Anne; Jørgensen, Rasmus

    2012-01-01

    , the glucagon receptor, and the receptors for parathyroid hormone (PTHR1 and PTHR2). The dysregulation of several family B1 receptors is involved in diseases, such as diabetes, chronic inflammation, and osteoporosis which underlines the pathophysiological importance of this GPCR subfamily. In spite of this......, investigation of family B1 receptor oligomerization and especially its pharmacological importance is still at an early stage. Even though GPCR oligomerization is a well-established phenomenon, there is a need for more investigations providing a direct link between these interactions and receptor functionality...... in family B1 GPCRs. One example of the functional effects of GPCR oligomerization is the facilitation of allosterism including cooperativity in ligand binding to GPCRs. Here, we review the currently available data on family B1 GPCR homo- and heteromerization, mainly based on BRET investigations. Furthermore...

  3. Bioluminescence resonance energy transfer methods to study G protein-coupled receptor-receptor tyrosine kinase heteroreceptor complexes.

    Science.gov (United States)

    Borroto-Escuela, Dasiel O; Flajolet, Marc; Agnati, Luigi F; Greengard, Paul; Fuxe, Kjell

    2013-01-01

    A large body of evidence indicates that G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs) can form heteroreceptor complexes. In these complexes, the signaling from each interacting protomer is modulated to produce an integrated and therefore novel response upon agonist(s) activation. In the GPCR-RTK heteroreceptor complexes, GPCRs can activate RTK in the absence of added growth factor through the use of RTK signaling molecules. This integrative phenomenon is reciprocal and can place also RTK signaling downstream of GPCR. Formation of either stable or transient complexes by these two important classes of membrane receptors is involved in regulating all aspects of receptor function, from ligand binding to signal transduction, trafficking, desensitization, and downregulation among others. Functional phenomena can be modulated with conformation-specific inhibitors that stabilize defined GPCR states to abrogate both GPCR agonist- and growth factor-stimulated cell responses or by means of small interfering heteroreceptor complex interface peptides. The bioluminescence resonance energy transfer (BRET) technology has emerged as a powerful method to study the structure of heteroreceptor complexes closely associated with the study of receptor-receptor interactions in such complexes. In this chapter, we provide an overview of different BRET(2) assays that can be used to study the structure of GPCR-RTK heteroreceptor complexes and their functions. Various experimental designs for optimization of these experiments are also described. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. DEVELOPMENT OF PHARMACOLOGICAL TOOLS FOR THE IDENTIFICATION OF G PROTEIN-COUPLED RECEPTORS LIGANDS

    OpenAIRE

    Gilissen, Julie

    2016-01-01

    G protein-coupled receptors (GPCRs) represent the protein family most successfully targeted for treating human diseases. They couple to G proteins to mobilize second messenger pathways that lead to cellular responses and ultimately to physiological changes. However many are poorly characterized with few ligands reported or remain completely orphans. Therefore, there is a growing need for screening-compatible and sensitive assays in order to identify new ligands. The present project aims at...

  5. Class II G Protein-Coupled Receptors and Their Ligands in Neuronal Function and Protection

    OpenAIRE

    Martin, Bronwen; de Maturana, Rakel Lopez; Brenneman, Randall; Walent, Tom; Mattson, Mark P.; Maudsley, Stuart

    2005-01-01

    G protein-coupled receptors (GPCRs) play pivotal roles in regulating the function and plasticity of neuronal circuits in the nervous system. Among the myriad of GPCRs expressed in neural cells, class II GPCRs which couples predominantly to the Gs–adenylate cyclase–cAMP signaling pathway, have recently received considerable attention for their involvement in regulating neuronal survival. Neuropeptides that activate class II GPCRs include secretin, glucagon-like peptides (GLP-1 and GLP-2), grow...

  6. Reviews in molecular biology and biotechnology: transmembrane signaling by G protein-coupled receptors.

    Science.gov (United States)

    Luttrell, Louis M

    2008-07-01

    As the most diverse type of cell surface receptor, the importance heptahelical G protein-coupled receptors (GPCRs) to clinical medicine cannot be overestimated. Visual, olfactory and gustatory sensation, intermediary metabolism, cell growth and differentiation are all influenced by GPCR signals. The basic receptor-G protein-effector mechanism of GPCR signaling is tuned by a complex interplay of positive and negative regulatory events that amplify the effect of a hormone binding the receptor or that dampen cellular responsiveness. The association of heptahelical receptors with a variety of intracellular partners other than G proteins has led to the discovery of potential mechanisms of GPCR signaling that extend beyond the classical paradigms. While the physiologic relevance of many of these novel mechanisms of GPCR signaling remains to be established, their existence suggests that the mechanisms of GPCR signaling are even more diverse than previously imagined.

  7. 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

  8. Muscle relaxants and histamine release.

    Science.gov (United States)

    Moss, J

    1995-01-01

    Many anaesthetic drugs and adjuvants can cause the release of histamine by chemical (anaphylactoid) or immunologic (anaphylactic) mechanisms. While both types of reactions can be clinically indistinguishable, they are mechanistically different. In anaphylactoid reactions, only preformed mediators are released, of which histamine may be the most clinically important. In true immunologic reactions, mast cell degranulation occurs, and many vasoactive substances (including histamine) are released. Clinical signs and symptoms of both classes of reactions include hypotension (most common), tachycardia, bronchospasm, or cutaneous manifestations. Anaphylactoid reactions may occur commonly under anaesthesia in response to many drugs, including induction agents, some opiates, plasma expanders, and curariform relaxants. Anaphylactic reactions are far less common than anaphylactoid reactions, but they nevertheless represent more than half of the life-threatening reactions that occur in anaesthetic practice. Muscle relaxants are the most frequently implicated class of drugs; suxamethonium is the most common agent implicated in anaphylactic reactions during anaesthesia, but even drugs without apparent chemical histamine release (i.e., vecuronium) are frequently implicated in anaphylactic reactions.

  9. GPCR-OKB: the G Protein Coupled Receptor Oligomer Knowledge Base.

    NARCIS (Netherlands)

    Khelashvili, G.; Dorff, K.; Shan, J.; Camacho-Artacho, M.; Skrabanek, L.; Vroling, B.; Bouvier, M.; Devi, L.A.; George, S.R.; Javitch, J.A.; Lohse, M.J.; Milligan, G.; Neubig, R.R.; Palczewski, K.; Parmentier, M.; Pin, J.P.; Vriend, G.; Campagne, F.; Filizola, M.

    2010-01-01

    SUMMARY: Rapid expansion of available data about G Protein Coupled Receptor (GPCR) dimers/oligomers over the past few years requires an effective system to organize this information electronically. Based on an ontology derived from a community dialog involving colleagues using experimental and

  10. New functions and signaling mechanisms for the class of adhesion G protein-coupled receptors

    NARCIS (Netherlands)

    Liebscher, Ines; Ackley, Brian; Araç, Demet; Ariestanti, Donna M.; Aust, Gabriela; Bae, Byoung-Il; Bista, Bigyan R.; Bridges, James P.; Duman, Joseph G.; Engel, Felix B.; Giera, Stefanie; Goffinet, André M.; Hall, Randy A.; Hamann, Jörg; Hartmann, Nicole; Lin, Hsi-Hsien; Liu, Mingyao; Luo, Rong; Mogha, Amit; Monk, Kelly R.; Peeters, Miriam C.; Prömel, Simone; Ressl, Susanne; Schiöth, Helgi B.; Sigoillot, Séverine M.; Song, Helen; Talbot, William S.; Tall, Gregory G.; White, James P.; Wolfrum, Uwe; Xu, Lei; Piao, Xianhua

    2014-01-01

    The class of adhesion G protein-coupled receptors (aGPCRs), with 33 human homologs, is the second largest family of GPCRs. In addition to a seven-transmembrane alpha-helix-a structural feature of all GPCRs-the class of aGPCRs is characterized by the presence of a large N-terminal extracellular

  11. G protein-coupled receptors self-assemble in dynamics simulations of model bilayers

    NARCIS (Netherlands)

    Periole, Xavier; Huber, Thomas; Marrink, Siewert-Jan; Sakmar, Thomas P.

    2007-01-01

    Many integral membrane proteins assemble to form oligomeric structures in biological membranes. In particular, seven-transmembrane helical G protein-coupled receptors (GPCRs) appear to self-assemble constitutively in membranes, but the mechanism and physiological role of this assembly are unknown.

  12. New insights into the structure of Class B G protein-coupled receptors

    NARCIS (Netherlands)

    Hollenstein, H.; de Graaf, C.; Bortolato, A.; Wang, M-W; Marshall, F.; Stevens, R.C.

    2014-01-01

    The secretin-like (class B) family of G protein-coupled receptors (GPCRs) are key players in hormonal homeostasis and are interesting drug targets for the treatment of several metabolic disorders (such as type 2 diabetes, osteoporosis, and obesity) and nervous system diseases (such as migraine,

  13. Mast cell-derived histamine mediates cystitis pain.

    Directory of Open Access Journals (Sweden)

    Charles N Rudick

    2008-05-01

    Full Text Available Mast cells trigger inflammation that is associated with local pain, but the mechanisms mediating pain are unclear. Interstitial cystitis (IC is a bladder disease that causes debilitating pelvic pain of unknown origin and without consistent inflammation, but IC symptoms correlate with elevated bladder lamina propria mast cell counts. We hypothesized that mast cells mediate pelvic pain directly and examined pain behavior using a murine model that recapitulates key aspects of IC.Infection of mice with pseudorabies virus (PRV induces a neurogenic cystitis associated with lamina propria mast cell accumulation dependent upon tumor necrosis factor alpha (TNF, TNF-mediated bladder barrier dysfunction, and pelvic pain behavior, but the molecular basis for pelvic pain is unknown. In this study, both PRV-induced pelvic pain and bladder pathophysiology were abrogated in mast cell-deficient mice but were restored by reconstitution with wild type bone marrow. Pelvic pain developed normally in TNF- and TNF receptor-deficient mice, while bladder pathophysiology was abrogated. Conversely, genetic or pharmacologic disruption of histamine receptor H1R or H2R attenuated pelvic pain without altering pathophysiology.These data demonstrate that mast cells promote cystitis pain and bladder pathophysiology through the separable actions of histamine and TNF, respectively. Therefore, pain is independent of pathology and inflammation, and histamine receptors represent direct therapeutic targets for pain in IC and other chronic pain conditions.

  14. 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...

  15. Fluorescent Approaches for Understanding Interactions of Ligands with G Protein Coupled Receptors

    Science.gov (United States)

    Sridharan, Rajashri; Zuber, Jeffrey; Connelly, Sara M.; Mathew, Elizabeth; Dumont, Mark E.

    2014-01-01

    G Protein Coupled Receptors (GPCRs) are responsible for a wide variety of signaling responses in diverse cell types. Despite major advances in the determination of structures of this class of receptors, the underlying mechanisms by which binding of different types of ligands specifically elicits particular signaling responses remains unclear. The use of fluorescence spectroscopy can provide important information about the process of ligand binding and ligand dependent conformational changes in receptors, especially kinetic aspects of these processes, that can be difficult to extract from x-ray structures. We present an overview of the extensive array of fluorescent ligands that have been used in studies of GPCRs and describe spectroscopic approaches for assaying binding and probing the environment of receptor-bound ligands with particular attention to examples involving yeast pheromone receptors. In addition, we discuss the use of fluorescence spectroscopy for detecting and characterizing conformational changes in receptors induced by the binding of ligands. Such studies have provided strong evidence for diversity of receptor conformations elicited by different ligands, consistent with the idea that GPCRs are not simple on and off switches. This diversity of states constitutes an underlying mechanistic basis for biased agonism, the observation that different stimuli can produce different responses from a single receptor. It is likely that continued technical advances will allow fluorescence spectroscopy to play an important role in continued probing of structural transitions in GPCRs. PMID:24055822

  16. Histamine Induces ATP Release from Human Subcutaneous Fibroblasts, via Pannexin-1 Hemichannels, Leading to Ca2+ Mobilization and Cell Proliferation*

    Science.gov (United States)

    Pinheiro, Ana Rita; Paramos-de-Carvalho, Diogo; Certal, Mariana; Costa, Maria Adelina; Costa, Cristina; Magalhães-Cardoso, Maria Teresa; Ferreirinha, Fátima; Sévigny, Jean; Correia-de-Sá, Paulo

    2013-01-01

    Changes in the regulation of connective tissue ATP-mediated mechano-transduction and remodeling may be an important link to the pathogenesis of chronic pain. It has been demonstrated that mast cell-derived histamine plays an important role in painful fibrotic diseases. Here we analyzed the involvement of ATP in the response of human subcutaneous fibroblasts to histamine. Acute histamine application caused a rise in intracellular Ca2+ ([Ca2+]i) and ATP release from human subcutaneous fibroblasts via H1 receptor activation. Histamine-induced [Ca2+]i rise was partially attenuated by apyrase, an enzyme that inactivates extracellular ATP, and by blocking P2 purinoceptors with pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid) tetrasodium salt and reactive blue 2. [Ca2+]i accumulation caused by histamine was also reduced upon blocking pannexin-1 hemichannels with 10Panx, probenecid, or carbenoxolone but not when connexin hemichannels were inhibited with mefloquine or 2-octanol. Brefeldin A, an inhibitor of vesicular exocytosis, also did not block histamine-induced [Ca2+]i mobilization. Prolonged exposure of human subcutaneous fibroblast cultures to histamine favored cell growth and type I collagen synthesis via the activation of H1 receptor. This effect was mimicked by ATP and its metabolite, ADP, whereas the selective P2Y1 receptor antagonist, MRS2179, partially attenuated histamine-induced cell growth and type I collagen production. Expression of pannexin-1 and ADP-sensitive P2Y1 receptor on human subcutaneous fibroblasts was confirmed by immunofluorescence confocal microscopy and Western blot analysis. In conclusion, histamine induces ATP release from human subcutaneous fibroblasts, via pannexin-1 hemichannels, leading to [Ca2+]i mobilization and cell growth through the cooperation of H1 and P2 (probably P2Y1) receptors. PMID:23918924

  17. On the G-Protein-Coupled Receptor Heteromers and Their Allosteric Receptor-Receptor Interactions in the Central Nervous System: Focus on Their Role in Pain Modulation

    Directory of Open Access Journals (Sweden)

    Dasiel O. Borroto-Escuela

    2013-01-01

    Full Text Available The modulatory role of allosteric receptor-receptor interactions in the pain pathways of the Central Nervous System and the peripheral nociceptors has become of increasing interest. As integrators of nociceptive and antinociceptive wiring and volume transmission signals, with a major role for the opioid receptor heteromers, they likely have an important role in the pain circuits and may be involved in acupuncture. The delta opioid receptor (DOR exerts an antagonistic allosteric influence on the mu opioid receptor (MOR function in a MOR-DOR heteromer. This heteromer contributes to morphine-induced tolerance and dependence, since it becomes abundant and develops a reduced G-protein-coupling with reduced signaling mainly operating via β-arrestin2 upon chronic morphine treatment. A DOR antagonist causes a return of the Gi/o binding and coupling to the heteromer and the biological actions of morphine. The gender- and ovarian steroid-dependent recruitment of spinal cord MOR/kappa opioid receptor (KOR heterodimers enhances antinociceptive functions and if impaired could contribute to chronic pain states in women. MOR1D heterodimerizes with gastrin-releasing peptide receptor (GRPR in the spinal cord, mediating morphine induced itch. Other mechanism for the antinociceptive actions of acupuncture along meridians may be that it enhances the cross-desensitization of the TRPA1 (chemical nociceptor-TRPV1 (capsaicin receptor heteromeric channel complexes within the nociceptor terminals located along these meridians. Selective ionotropic cannabinoids may also produce cross-desensitization of the TRPA1-TRPV1 heteromeric nociceptor channels by being negative allosteric modulators of these channels leading to antinociception and antihyperalgesia.

  18. The Concise Guide to Pharmacology 2013/14: G Protein-Coupled Receptors

    Science.gov (United States)

    Alexander, Stephen PH; Benson, Helen E; Faccenda, Elena; Pawson, Adam J; Sharman, Joanna L; Spedding, Michael; Peters, John A; Harmar, Anthony J

    2013-01-01

    The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. G protein-coupled receptors are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates. PMID:24517644

  19. Discrete spatial organization of TGFβ receptors couples receptor multimerization and signaling to cellular tension.

    Science.gov (United States)

    Rys, Joanna P; DuFort, Christopher C; Monteiro, David A; Baird, Michelle A; Oses-Prieto, Juan A; Chand, Shreya; Burlingame, Alma L; Davidson, Michael W; Alliston, Tamara N

    2015-12-10

    Cell surface receptors are central to the cell's ability to generate coordinated responses to the multitude of biochemical and physical cues in the microenvironment. However, the mechanisms by which receptors enable this concerted cellular response remain unclear. To investigate the effect of cellular tension on cell surface receptors, we combined novel high-resolution imaging and single particle tracking with established biochemical assays to examine TGFβ signaling. We find that TGFβ receptors are discretely organized to segregated spatial domains at the cell surface. Integrin-rich focal adhesions organize TβRII around TβRI, limiting the integration of TβRII while sequestering TβRI at these sites. Disruption of cellular tension leads to a collapse of this spatial organization and drives formation of heteromeric TβRI/TβRII complexes and Smad activation. This work details a novel mechanism by which cellular tension regulates TGFβ receptor organization, multimerization, and function, providing new insight into the mechanisms that integrate biochemical and physical cues.

  20. Procedure for Calculation of Potency and Efficacy for Ligands Acting on G(s)- and G (i)-Coupled Receptors

    DEFF Research Database (Denmark)

    Meier, Eddi; Schousboe, Arne; Belhage, Bo

    2012-01-01

    may lead to significant errors as compounds mediating their effects via G(s) coupled receptors may appear more potent and efficacious than they actually are. Contrary, compounds mediating their effects via G(i) coupled receptors may appear less potent and efficacious than they are in reality. Potency...

  1. GPR99, a new G protein-coupled receptor with homology to a new subgroup of nucleotide receptors

    Directory of Open Access Journals (Sweden)

    Chica Schaller H

    2002-07-01

    Full Text Available Abstract Background Based on sequence similarity, the superfamily of G protein-coupled receptors (GPRs can be subdivided into several subfamilies, the members of which often share similar ligands. The sequence data provided by the human genome project allows us to identify new GPRs by in silico homology screening, and to predict their ligands. Results By searching the human genomic database with known nucleotide receptors we discovered the gene for GPR99, a new orphan GPR. The mRNA of GPR99 was found in kidney and placenta. Phylogenetic analysis groups GPR99 into the P2Y subfamily of GPRs. Based on the phylogenetic tree we propose a new classification of P2Y nucleotide receptors into two subgroups predicting a nucleotide ligand for GPR99. By assaying known nucleotide ligands on heterologously expressed GPR99, we could not identify specifically activating substances, indicating that either they are not agonists of GPR99 or that GPR99 was not expressed at the cell surface. Analysis of the chromosomal localization of all genes of the P2Y subfamily revealed that all members of subgroup "a" are encoded by less than 370 kb on chromosome 3q24, and that the genes of subgroup "b" are clustered on one hand to chromosome 11q13.5 and on the other on chromosome 3q24-25.1 close to the subgroup "a" position. Therefore, the P2Y subfamily is a striking example for local gene amplification. Conclusions We identified a new orphan receptor, GPR99, with homology to the family of G protein-coupled nucleotide receptors. Phylogenetic analysis separates this family into different subgroups predicting a nucleotide ligand for GPR99.

  2. Histamine stimulates secretion of extracellular vesicles with nucleotidase activity in rat submandibular gland.

    Science.gov (United States)

    González, Débora Alejandra; Barbieri van Haaster, Martín Matías; Quinteros Villarruel, Emmanuel; Brandt, Macarena; Benítez, María Belén; Stranieri, Graciela Mabel; Orman, Betina

    2018-01-01

    Extracellular vesicles released by different cells have been isolated from diverse fluids including saliva. We previously reported that rat submandibular glands secrete nanovesicles that catalyze hydrolysis of ATP, ADP and AMP, which are actors of the purinergic signaling system along with adenosine. Extracellular nucleotides like ATP and adenosine are involved in the regulation of inflammatory processes and apoptosis. Histamine, a widely distributed biogenic amine, is involved in inflammatory response. To test if activation of histamine receptors in rat submandibular gland promotes changes in the release of vesicles with nucleotidase activity that could modulate purinergic signaling. Rat submandibular glands were incubated in the absence or presence of histamine and JNJ7777120, an antagonist for H 4 receptors. Extracellular vesicles were isolated from incubation media by differential centrifugation. Vesicular nucleotidase activity was measured following Pi release by 3mM MgATP, MgADP or MgAMP. Histamine increased the release of vesicles with nucleotidase activity in a concentration dependent manner. JNJ7777120 significantly reduced this effect. Vesicular nucleotidases obtained in the absence or presence of histamine promoted Pi production from ATP, ADP and AMP. The results show a relationship between histamine and the regulation of purinergic signaling, which could be important in the modulation of inflammatory processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Assessment and Challenges of Ligand Docking into Comparative Models of G-Protein Coupled Receptors

    DEFF Research Database (Denmark)

    Nguyen, E.D.; Meiler, J.; Norn, C.

    2013-01-01

    The rapidly increasing number of high-resolution X-ray structures of G-protein coupled receptors (GPCRs) creates a unique opportunity to employ comparative modeling and docking to provide valuable insight into the function and ligand binding determinants of novel receptors, to assist in virtual...... and side-chain conformational space with Rosetta can be leveraged to meet this challenge. This study performs unbiased comparative modeling and docking methodologies using 14 distinct high-resolution GPCRs and proposes knowledge-based filtering methods for improvement of sampling performance...... and identification of correct ligand-receptor interactions. On average, top ranked receptor models built on template structures over 50% sequence identity are within 2.9 Å of the experimental structure, with an average root mean square deviation (RMSD) of 2.2 Å for the transmembrane region and 5 Å for the second...

  4. 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.

  5. Neurovascular coupling to D2/D3 dopamine receptor occupancy using simultaneous PET/functional MRI

    DEFF Research Database (Denmark)

    Sander, Christin Y; Hooker, Jacob M; Catana, Ciprian

    2013-01-01

    This study employed simultaneous neuroimaging with positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to demonstrate the relationship between changes in receptor occupancy measured by PET and changes in brain activity inferred by fMRI. By administering the D2/D3...... responses and receptor occupancies. The distinct CBV magnitudes between putamen and caudate at matched occupancies approximately matched literature differences in basal dopamine levels, suggesting that the relative fMRI measurements reflect basal D2/D3 dopamine receptor occupancy. These results can provide...... a basis for models that relate dopaminergic occupancies to hemodynamic changes in the basal ganglia. Overall, these data demonstrate the utility of simultaneous PET/fMRI for investigations of neurovascular coupling that correlate neurochemistry with hemodynamic changes in vivo for any receptor system...

  6. The origins of diversity and specificity in g protein-coupled receptor signaling.

    Science.gov (United States)

    Maudsley, Stuart; Martin, Bronwen; Luttrell, Louis M

    2005-08-01

    The modulation of transmembrane signaling by G protein-coupled receptors (GPCRs) constitutes the single most important therapeutic target in medicine. Drugs acting on GPCRs have traditionally been classified as agonists, partial agonists, or antagonists based on a two-state model of receptor function embodied in the ternary complex model. Over the past decade, however, many lines of investigation have shown that GPCR signaling exhibits greater diversity and "texture" than previously appreciated. Signal diversity arises from numerous factors, among which are the ability of receptors to adopt multiple "active" states with different effector-coupling profiles; the formation of receptor dimers that exhibit unique pharmacology, signaling, and trafficking; the dissociation of receptor "activation" from desensitization and internalization; and the discovery that non-G protein effectors mediate some aspects of GPCR signaling. At the same time, clustering of GPCRs with their downstream effectors in membrane microdomains and interactions between receptors and a plethora of multidomain scaffolding proteins and accessory/chaperone molecules confer signal preorganization, efficiency, and specificity. In this context, the concept of agonist-selective trafficking of receptor signaling, which recognizes that a bound ligand may select between a menu of active receptor conformations and induce only a subset of the possible response profile, presents the opportunity to develop drugs that change the quality as well as the quantity of efficacy. As a more comprehensive understanding of the complexity of GPCR signaling is developed, the rational design of ligands possessing increased specific efficacy and attenuated side effects may become the standard mode of drug development.

  7. G protein-coupled receptor signaling complexity in neuronal tissue: implications for novel therapeutics.

    Science.gov (United States)

    Maudsley, Stuart; Martin, Bronwen; Luttrell, Louis M

    2007-02-01

    The manipulation of transmembrane signaling by G protein-coupled receptors (GPCRs) constitutes perhaps the single most important therapeutic target in medicine. Therapeutics acting on GPCRs have traditionally been classified as agonists, partial agonists, or antagonists based on a two state model of receptor function embodied in the ternary complex model. Over the past decade, however, many lines of investigation have shown that GPCR signaling exhibits greater diversity and 'texture' than previously appreciated. Signal diversity arises from numerous factors, among them the ability of receptors to adopt multiple 'active' states with different effector coupling profiles, the formation of receptor dimers that exhibit unique pharmacology, signaling, and trafficking, the dissociation of receptor 'activation' from desensitization and internalization, and the discovery that non-G protein effectors mediate some aspects of GPCR signaling. At the same time, clustering of GPCRs with their downstream effectors in membrane microdomains, and interactions between receptors and a plethora of multidomain scaffolding proteins and accessory/chaperone molecules confers signal preorganization, efficiency, and specificity. More importantly it is likely that alteration in the interactions of these proteins with GPCRs may occur in aging or neurodegenerative disorders, thus defining a distinct 'pharmacology' from that seen in young organisms or normal physiology. In this context, the concept of agonist selective trafficking of receptor signaling, which recognizes that a bound ligand may select between a menu of 'active' receptor conformations and induce only a subset of the possible response profile, presents the opportunity to develop drugs that change the quality as well as the quantity of efficacy and enhance these qualities for specific disorders or other paradigms. As a more comprehensive understanding of the complexity of GPCR signaling is developed, the rational design of ligands

  8. TRPA1, substance P, histamine and 5-hydroxytryptamine interact in an interdependent way to induce nociception.

    Science.gov (United States)

    Fischer, Luana; Lavoranti, Maria Isabel; de Oliveira Borges, Mariana; Miksza, Alana Farias; Sardi, Natalia Fantin; Martynhak, Bruno Jacson; Tambeli, Claudia H; Parada, Carlos Amílcar

    2017-04-01

    Although TRPA1, SP, histamine and 5-hydroxytryptamine (5-HT) have recognized contribution to nociceptive mechanisms, little is known about how they interact with each other to mediate inflammatory pain in vivo. In this study we evaluated whether TRPA1, SP, histamine and 5-HT interact, in an interdependent way, to induce nociception in vivo. The subcutaneous injection of the TRPA1 agonist allyl isothiocyanate (AITC) into the rat's hind paw induced a dose-dependent and short lasting behavioral nociceptive response that was blocked by the co-administration of the TRPA1 antagonist, HC030031, or by the pretreatment with antisense ODN against TRPA1. AITC-induced nociception was significantly decreased by the co-administration of selective antagonists for the NK1 receptor for substance P, the H1 receptor for histamine and the 5-HT1A or 3 receptors for 5-HT. Histamine- or 5-HT-induced nociception was decreased by the pretreatment with antisense ODN against TRPA1. These findings suggest that AITC-induced nociception depends on substance P, histamine and 5-HT, while histamine- or 5-HT-induced nociception depends on TRPA1. Most important, AITC interact in a synergistic way with histamine, 5-HT or substance P, since their combination at non-nociceptive doses induced a nociceptive response much higher than that expected by the sum of the effect of each one alone. This synergistic effect is dependent on the H1, 5-HT1A or 3 receptors. Together, these findings suggest a self-sustainable cycle around TRPA1, no matter where the cycle is initiated each step is achieved and even subeffective activation of more than one step results in a synergistic activation of the overall cycle.

  9. Histamine-Induced Dilation of Isolated Porcine Retinal Arterioles: Role of Endothelium-Derived Hyperpolarizing Factor.

    Science.gov (United States)

    Otani, Shinichi; Nagaoka, Taiji; Omae, Tsuneaki; Tanano, Ichiro; Kamiya, Takayuki; Ono, Shinji; Hein, Travis W; Kuo, Lih; Yoshida, Akitoshi

    2016-09-01

    Although endothelium-dependent nitric oxide (NO)-mediated dilation of retinal arterioles has been well described, the role of endothelium-derived hyperpolarizing factor (EDHF) in the retinal arteriolar response remains unclear. In the current study, we examined the contribution of EDHF to the retinal arteriolar dilation to the inflammatory agent histamine and investigated the signaling mechanisms underlying this vasomotor activity. Porcine retinal arterioles were isolated, cannulated, and pressurized without flow for functional study by using video microscopic techniques. The immunohistochemical staining was performed to determine histamine receptor subtypes. Histamine (0.1-30 μM) produced concentration-dependent dilation of retinal arterioles in a manner sensitive to H1- and H2-receptor antagonists chlorpheniramine and famotidine, respectively. Histamine-induced vasodilation was almost abolished after endothelial removal. In the intact vessels, vasodilation to histamine was partially inhibited by the inhibitors of cyclooxygenase (indomethacin), NO synthase (NG-nitro-L-arginine methyl ester, L-NAME), or Ca2+ -activated K+ (KCa) channels (apamin plus charybdotoxin). Combination of the above inhibitors abolished histamine-induced vasodilation. Residual vasodilation in the presence of indomethacin and L-NAME was further reduced by the cytochrome P450 enzyme inhibitor sulfaphenazole but not by the gap junction inhibitor carbenoxolone or the hydrogen peroxide scavenger catalase. Immunohistochemical signals for H1- and H2-receptor expression were found only in the endothelium. The endothelium plays an essential role in the dilation of porcine retinal arterioles to histamine via H1- and H2-receptor activation. The EDHF derived from cytochrome P450 contributed in part to this vasodilation via KCa channel activation, in addition to the endothelial release of NO and prostanoids.

  10. The inhibitory effect of simvastatin and aspirin on histamine responsiveness in human vascular endothelial cells.

    Science.gov (United States)

    Absi, Mais; Bruce, Jason I; Ward, Donald T

    2014-04-01

    Statins and aspirin deliver well-established cardiovascular benefits resulting in their increased use as combined polypills to decrease risk of stroke and heart disease. However, the direct endothelial effect of combined statin/aspirin cotreatment remains unclear. Histamine is an inflammatory mediator that increases vascular permeability, and so we examined the effect of treating human umbilical vein endothelial cells (HUVECs) for 24 h with 1 μM simvastatin and 100 μM aspirin on histamine responsiveness. Subsequent histamine (1 μM) challenge increased intracellular calcium (Ca(2+)i) concentration, an effect that was significantly inhibited by combined simvastatin/aspirin pretreatment but not when then the compounds were given separately, even at 10-fold higher concentrations. In contrast, the Ca(2+)i mobilization response to ATP challenge (10 μM) was not inhibited by combined simvastatin/aspirin pretreatment. The H1 receptor antagonist pyrilamine significantly inhibited both histamine-induced Ca(2+)i mobilization and extracellular signal-regulated kinase (ERK) activation, whereas ranitidine (H2 receptor antagonist) was without effect. However, combined simvastatin/aspirin pretreatment failed to decrease H1 receptor protein expression ruling out receptor downregulation as the mechanism of action. Histamine-induced ERK activation was also inhibited by atorvastatin pretreatment, while simvastatin further inhibited histamine-induced vascular endothelial cadherin phosphorylation as well as altered HUVEC morphology and inhibited actin polymerization. Therefore, in addition to the known therapeutic benefits of statins and aspirin, here we provide initial cellular evidence that combined statin/aspirin treatment inhibits histamine responsiveness in HUVECs.

  11. G protein-coupled receptor accessory proteins and signaling: pharmacogenomic insights.

    Science.gov (United States)

    Thompson, Miles D; Cole, David E C; Jose, Pedro A; Chidiac, Peter

    2014-01-01

    The identification and characterization of the genes encoding G protein-coupled receptors (GPCRs) and the proteins necessary for the processes of ligand binding, GPCR activation, inactivation, and receptor trafficking to the membrane are discussed in the context of human genetic disease. In addition to functional GPCR variants, the identification of genetic disruptions affecting proteins necessary to GPCR functions have provided insights into the function of these pathways. Gsα and Gβ subunit polymorphisms have been found to result in complex phenotypes. Disruptions in accessory proteins that normally modify or organize heterotrimeric G-protein coupling may also result in disease states. These include the contribution of variants of the regulator of G protein signaling (RGS) protein to hypertension; the role variants of the activator of G protein signaling (AGS) proteins to phenotypes (such as the type III AGS8 variant to hypoxia); the contribution of G protein-coupled receptor kinase (GRK) proteins, such as GRK4, in disorders such as hypertension. The role of accessory proteins in GPCR structure and function is discussed in the context of genetic disorders associated with disruption of the genes that encode them. An understanding of the pharmacogenomics of GPCR and accessory protein signaling provides the basis for examining both GPCR pharmacogenetics and the genetics of monogenic disorders that result from disruption of given receptor systems.

  12. The significance of G protein-coupled receptor crystallography for drug discovery.

    Science.gov (United States)

    Salon, John A; Lodowski, David T; Palczewski, Krzysztof

    2011-12-01

    Crucial as molecular sensors for many vital physiological processes, seven-transmembrane domain G protein-coupled receptors (GPCRs) comprise the largest family of proteins targeted by drug discovery. Together with structures of the prototypical GPCR rhodopsin, solved structures of other liganded GPCRs promise to provide insights into the structural basis of the superfamily's biochemical functions and assist in the development of new therapeutic modalities and drugs. One of the greatest technical and theoretical challenges to elucidating and exploiting structure-function relationships in these systems is the emerging concept of GPCR conformational flexibility and its cause-effect relationship for receptor-receptor and receptor-effector interactions. Such conformational changes can be subtle and triggered by relatively small binding energy effects, leading to full or partial efficacy in the activation or inactivation of the receptor system at large. Pharmacological dogma generally dictates that these changes manifest themselves through kinetic modulation of the receptor's G protein partners. Atomic resolution information derived from increasingly available receptor structures provides an entrée to the understanding of these events and practically applying it to drug design. Supported by structure-activity relationship information arising from empirical screening, a unified structural model of GPCR activation/inactivation promises to both accelerate drug discovery in this field and improve our fundamental understanding of structure-based drug design in general. This review discusses fundamental problems that persist in drug design and GPCR structural determination.

  13. Protective effect of histamine microinjected into cerebellar fastigial nucleus on stress gastric mucosal damage in rats.

    Science.gov (United States)

    Qiao, Xiao; Yang, Jun; Fei, Su-Juan; Zhu, Jin-Zhou; Zhu, Sheng-Ping; Liu, Zhang-Bo; Li, Ting-Ting; Zhang, Jian-Fu

    2015-12-10

    In the study, we investigated the effect of histamine microinjected into cerebellar fastigial nucleus (FN) on stress gastric mucosal damage (SGMD), and its mechanisms in rats. The model of SGMD was established by restraining and water (21±1°C)-immersion for 3h. The gastric mucosal damage index (GMDI) indicated the severity of gastric mucosal damage. Histamine or receptor antagonist was microinjected into the FN. The decussation of superior cerebellar peduncle (DSCP) and the lateral hypothalamic area (LHA) were destroyed, respectively. The pathological changes of gastric mucosa were evaluated using biological signal acquisition system, Laser-Doppler flowmeter, and western blotting. We found that the microinjection of histamine (0.05, 0.5, and 5μg) into FN significantly attenuated the SGMD, in a dose-dependent manner, whereas, the microinjection of histamine H2 receptor antagonist, ranitidine, and glutamic acid decarboxylase antagonist, 3-mercaptopropionic acid (3-MPA) exacerbated the SGMD. The protective effect of histamine on SGMD was abolished by electrical lesion of DSCP or chemical ablation of LHA. The microinjection of histamine decreased the discharge frequency of the greater splanchnic nerve, and the gastric mucosal blood flow was increased. In addition, the cellular proliferation was enhanced, but the cellular apoptosis was reduced in the gastric mucosa. Also the pro-apoptosis protein, Bax, and caspase-3 were down-regulated, and the anti-apoptosis protein, Bcl-2 was up-regulated following microinjection of histamine. In conclusion, the FN participated in the regulation of SGMD after histamine microinjected into FN, and cerebellar-hypothalamic circuits (include: DSCP, LHA) contribute to the process, which may provide a new therapeutic strategy for SGMD. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Histamine-dependent prolongation by aldosterone of vasoconstriction in isolated small mesenteric arteries of the mouse

    DEFF Research Database (Denmark)

    Schjerning, Jeppe; Uhrenholt, Torben R; Svenningsen, Per

    2013-01-01

    inhibits recovery by stimulation of histamine release from mast cells along mesenteric arteries. The resulting activation of H2 receptors decreases the sensitivity to NO of vascular smooth muscle cells. Aldosterone may chronically affect vascular function through paracrine release of histamine....... in arteries from wild type mice and the SNP-mediated dilatation in arteries from eNOS(-/-) mice was inhibited by the histamine H2 receptor antagonist cimetidine. RT-PCR showed expression of mast cell markers in mouse mesenteric arteries. The adventitia displayed granular cells positive for toluidine blue...... vital stain. Confocal microscopy of live mast cells showed loss of quinacrine fluorescence and swelling after aldosterone treatment indicating degranulation. RT-PCR showed expression of mineralocorticoid receptors in mesenteric arteries and in isolated mast cells. These findings suggest that aldosterone...

  15. The effects of crocin and safranal on the yawning induced by intracerebroventricular injection of histamine in rats

    Directory of Open Access Journals (Sweden)

    Mina Taati

    2016-06-01

    Full Text Available Objective: Crocin and safranal, as the major constituents of saffron, have many biological activities. This study investigated the effects of crocin and safranal on yawning response induced by intracerebroventricular (i.c.v. injection of histamine in rats. Materials and Methods: In ketamine/xylazine-anesthetized rats, a guide cannula was implanted in the right ventricle of the brain and yawning induced by i.c.v. injection of histamine. Crocin and safranal were intraperitoneally (i.p. injected alone and before i.c.v. injection of histamine. Results: Histamine at the doses of 10 and 20 µg/rat produced yawning. Mepyramine (a histamine H1 receptor antagonist 40 µg/rat significantly (p

  16. Ligand-specific regulation of the extracellular surface of a G-protein-coupled receptor

    Energy Technology Data Exchange (ETDEWEB)

    Bokoch, Michael P.; Zou, Yaozhong; Rasmussen, Søren G.F.; Liu, Corey W.; Nygaard, Rie; Rosenbaum, Daniel M.; Fung, Juan José; Choi, Hee-Jung; Thian, Foon Sun; Kobilka, Tong Sun; Puglisi, Joseph D.; Weis, William I.; Pardo, Leonardo; Prosser, R. Scott; Mueller, Luciano; Kobilka, Brian K. (Stanford-MED); (Toronto); (BMS); (UAB, Spain)

    2010-01-14

    G-protein-coupled receptors (GPCRs) are seven-transmembrane proteins that mediate most cellular responses to hormones and neurotransmitters. They are the largest group of therapeutic targets for a broad spectrum of diseases. Recent crystal structures of GPCRs have revealed structural conservation extending from the orthosteric ligand-binding site in the transmembrane core to the cytoplasmic G-protein-coupling domains. In contrast, the extracellular surface (ECS) of GPCRs is remarkably diverse and is therefore an ideal target for the discovery of subtype-selective drugs. However, little is known about the functional role of the ECS in receptor activation, or about conformational coupling of this surface to the native ligand-binding pocket. Here we use NMR spectroscopy to investigate ligand-specific conformational changes around a central structural feature in the ECS of the {beta}{sub 2} adrenergic receptor: a salt bridge linking extracellular loops 2 and 3. Small-molecule drugs that bind within the transmembrane core and exhibit different efficacies towards G-protein activation (agonist, neutral antagonist and inverse agonist) also stabilize distinct conformations of the ECS. We thereby demonstrate conformational coupling between the ECS and the orthosteric binding site, showing that drugs targeting this diverse surface could function as allosteric modulators with high subtype selectivity. Moreover, these studies provide a new insight into the dynamic behaviour of GPCRs not addressable by static, inactive-state crystal structures.

  17. Structural Basis for Receptor Activity-Modifying Protein-Dependent Selective Peptide Recognition by a G Protein-Coupled Receptor.

    Science.gov (United States)

    Booe, Jason M; Walker, Christopher S; Barwell, James; Kuteyi, Gabriel; Simms, John; Jamaluddin, Muhammad A; Warner, Margaret L; Bill, Roslyn M; Harris, Paul W; Brimble, Margaret A; Poyner, David R; Hay, Debbie L; Pioszak, Augen A

    2015-06-18

    Association of receptor activity-modifying proteins (RAMP1-3) with the G protein-coupled receptor (GPCR) calcitonin receptor-like receptor (CLR) enables selective recognition of the peptides calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) that have diverse functions in the cardiovascular and lymphatic systems. How peptides selectively bind GPCR:RAMP complexes is unknown. We report crystal structures of CGRP analog-bound CLR:RAMP1 and AM-bound CLR:RAMP2 extracellular domain heterodimers at 2.5 and 1.8 Å resolutions, respectively. The peptides similarly occupy a shared binding site on CLR with conformations characterized by a β-turn structure near their C termini rather than the α-helical structure common to peptides that bind related GPCRs. The RAMPs augment the binding site with distinct contacts to the variable C-terminal peptide residues and elicit subtly different CLR conformations. The structures and accompanying pharmacology data reveal how a class of accessory membrane proteins modulate ligand binding of a GPCR and may inform drug development targeting CLR:RAMP complexes. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  18. Characterization of rabbit ileal receptors for Clostridium difficile toxin A. Evidence for a receptor-coupled G protein

    Energy Technology Data Exchange (ETDEWEB)

    Pothoulakis, C.; LaMont, J.T.; Eglow, R.; Gao, N.; Rubins, J.B.; Theoharides, T.C.; Dickey, B.F. (Boston Univ. School of Medicine, MA (USA))

    1991-07-01

    The purpose of this study was to characterize the surface receptor for toxin A, the enterotoxin from Clostridium difficile, on rabbit intestinal brush borders (BB) and on rat basophilic leukemia (RBL) cells. Purified toxin A was radiolabeled using a modified Bolton-Hunter method to sp act 2 microCi/micrograms, with retention of full biologic activity. 3H-Toxin A bound specifically to a single class of receptors on rabbit BB and on RBL cells with dissociation constants of 5.4 x 10(-8) and 3.5 x 10(-8) M, respectively. RBL cells were highly sensitive to toxin A (cell rounding) and had 180,000 specific binding sites per cell, whereas IMR-90 fibroblasts were far less sensitive to toxin A and lacked detectable specific binding sites. Exposure of BB to trypsin or chymotrypsin significantly reduced 3H-toxin A specific binding. Preincubation of BB with Bandeirea simplicifolia (BS-1) lectin also reduced specific binding, and CHAPS-solubilized receptors could be immobilized with WGA-agarose. The addition of 100 nM toxin A accelerated the association of 35S-GTP gamma S with rabbit ileal BB, and preincubation of BB with the GTP analogues GTP gamma S or Gpp(NH)p, significantly reduced 3H-toxin A specific binding. Our data indicate that the membrane receptor for toxin A is a galactose and N-acetyl-glucosamine-containing glycoprotein which appears to be coupled to a G protein.

  19. Histamine and mast cell activator compound 48/80 are safe but inefficient systemic adjuvants for gilthead seabream vaccination.

    Science.gov (United States)

    Gómez González, N E; Cabas, I; Montero, J; García Alcázar, A; Mulero, V; García Ayala, A

    2017-07-01

    Histamine has a key role in the regulation of inflammatory and innate immune responses in vertebrates. Gilthead seabream (Sparus aurata L.), a marine hermaphrodite teleost of great commercial value, was the first fish species shown to possess histamine-containing mast cells (MCs) at mucosal tissues. MCs are highly abundant in the peritoneal exudate of gilthead seabream and compound 48/80 (Co 48/80), often used to promote MC activation and histamine release, is able to promote histamine release from gilthead seabream MCs in vitro and in vivo. The aim of the present study was to analyze the effect of histamine and Co 48/80 on the immune responses of gilthead seabream. For this purpose, histamine and Co 48/80 were intraperitoneally injected alone or combined with 109 heat-killed Vibrio anguillarum cells and their effects on head kidney and peritoneal exudate were analyzed. The results indicated that although histamine and Co 48/80 were both able to alter the percentage of peritoneal exudate and head kidney immune cell types, only Co 48/80 increased reactive oxygen species production by peritoneal leukocytes. In addition, histamine, but not Co 48/80, was able to slightly impair the humoral adaptive immune response, i.e. production of specific IgM to V. anguillarum. Notably, both histamine and Co 48/80 reduced the expression of the gene encoding histamine receptor H2 in peritoneal exudate leukocytes. These results show for the first time in fish that although systemic administration of histamine and Co 48/80 is safe, neither compound can be regarded as an efficient adjuvant for gilthead seabream vaccination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Histamine induces activation of protein kinase D that mediates tissue factor expression and activity in human aortic smooth muscle cells

    Science.gov (United States)

    Hao, Feng; Wu, Daniel Dongwei; Xu, Xuemin

    2012-01-01

    Histamine, an inflammatory mediator, has been shown to influence the pathogenesis of vascular wall cells. However, the molecular basis of its influence is not well understood. Our data reveal that histamine markedly induces protein kinase D (PKD) activation in human aortic smooth muscle cells. PKD belongs to a family of serine/threonine protein kinases, and its function in vascular disease is largely unknown. Our data show that histamine-induced PKD phosphorylation is dependent on the activation of histamine receptor 1 and protein kinase C (PKC). To determine the role of PKD in the histamine pathway, we employed a small-interfering RNA approach to downregulate PKD expression and found that PKD1 and PKD2 are key mediators for expression of tissue factor (TF), which is the key initiator of blood coagulation and is important for thrombosis. Our results show that PKD2 predominantly mediates histamine-induced TF expression via the p38 mitogen-activated protein kinase (MAPK) pathway, whereas PKD1 mediates histamine-induced TF expression through a p38 MAPK-independent pathway. We demonstrate that histamine induces TF expression via the PKC-dependent PKD activation. Our data provide the first evidence that PKD is a new component in histamine signaling in live cells and that PKD has a novel function in the histamine signaling pathway leading to gene expression, as evidenced by TF expression. Importantly, our data reveal a regulatory link from histamine to PKD and TF, providing new insights into the mechanisms of coagulation and the development of atherothrombosis. PMID:23001835

  1. Ligand-binding kinetics on histamine receptors

    NARCIS (Netherlands)

    Bosma, Reggie; Mocking, T.A.M.; Leurs, R.; Vischer, H.F.

    2017-01-01

    Equilibrium-binding affinities of ligands for a drug target do not always accurately reflect the success of drug candidates in the clinic. Affinity-based predictions concerning competitive antagonism on the target will only be accurate if equilibrium binding of both ligands is allowed. Unless

  2. PDZ domain-mediated interactions of G protein-coupled receptors with postsynaptic density protein 95

    DEFF Research Database (Denmark)

    Møller, Thor C; Wirth, Volker F; Roberts, Nina Ingerslev

    2013-01-01

    G protein-coupled receptors (GPCRs) constitute the largest family of membrane proteins in the human genome. Their signaling is regulated by scaffold proteins containing PDZ domains, but although these interactions are important for GPCR function, they are still poorly understood. We here present...... a quantitative characterization of the kinetics and affinity of interactions between GPCRs and one of the best characterized PDZ scaffold proteins, postsynaptic density protein 95 (PSD-95), using fluorescence polarization (FP) and surface plasmon resonance (SPR). By comparing these in vitro findings....... The approach can easily be transferred to other receptors and scaffold proteins and this could help accelerate the discovery and quantitative characterization of GPCR-PDZ interactions....

  3. Understanding the Added Value of G-Protein-Coupled Receptor Heteromers

    Directory of Open Access Journals (Sweden)

    Nuria Franco

    2014-01-01

    Full Text Available G-protein-coupled receptors (GPCRs constitute the most populated family of proteins within the human genome. Since the early sixties work on GPCRs and on GPCR-mediated signaling has led to a number of awards, the most recent being the Nobel Prize in Chemistry for 2012. The future of GPCRs research is surely based on their capacity for heteromerization. Receptor heteromers offer a series of challenges that will help in providing success in academic/basic research and translation into more effective and safer drugs.

  4. Ligand-specific regulation of the extracellular surface of a G-protein-coupled receptor

    DEFF Research Database (Denmark)

    Bokoch, Michael P; Zou, Yaozhong; Rasmussen, Søren Gøgsig Faarup

    2010-01-01

    G-protein-coupled receptors (GPCRs) are seven-transmembrane proteins that mediate most cellular responses to hormones and neurotransmitters. They are the largest group of therapeutic targets for a broad spectrum of diseases. Recent crystal structures of GPCRs have revealed structural conservation...... receptor: a salt bridge linking extracellular loops 2 and 3. Small-molecule drugs that bind within the transmembrane core and exhibit different efficacies towards G-protein activation (agonist, neutral antagonist and inverse agonist) also stabilize distinct conformations of the ECS. We thereby demonstrate...

  5. A novel human gene encoding a G-protein-coupled receptor (GPR15) is located on chromosome 3

    Energy Technology Data Exchange (ETDEWEB)

    Heiber, M.; Marchese, A.; O`Dowd, B.F. [Univ. of Toronto, Ontario (Canada)] [and others

    1996-03-05

    We used sequence similarities among G-protein-coupled receptor genes to discover a novel receptor gene. Using primers based on conserved regions of the opioid-related receptors, we isolated a PCR product that was used to locate the full-length coding region of a novel human receptor gene, which we have named GPR15. A comparison of the amino acid sequence of the receptor gene, which we have named GPR15. A comparison of the amino acid sequence of the receptor encoded by GPR15 with other receptors revealed that it shared sequence identity with the angiotensin II AT1 and AT2 receptors, the interleukin 8b receptor, and the orphan receptors GPR1 and AGTL1. GPR15 was mapped to human chromosome 3q11.2-q13.1. 12 refs., 2 figs.

  6. Histamine and Tyramine in Food.

    Science.gov (United States)

    1985-05-01

    CATALOG NUMBER AFIT/CI/NR 85-62T ___ _ 4. TITLE (and Subtitle) S. TYPE OF REPORT & PERIOD COVERED Histamine and Tyramine in Food THESIS /D/ -y)j49 S...Tyramine from Theobroma Cacoa. Phytochemistry . 16:1602. (78) Udenfriend, S., W. Lovenberg and A. Sjoerdsma. 1959. Physiologically Active Amines in Common...Polyphenols Isolated from the Leaves. Phytochemistry , 6:417-422. (89) Wheaton, T. A. and I. Stewart. 1970. The Distribution of Tyramine, N-methyltyrauine

  7. Histaminuria from histamine-rich foods.

    Science.gov (United States)

    Feldman, J M

    1983-11-01

    Using a highly specific and sensitive assay, the histamine content of foodstuffs and the effect of ingesting these foodstuffs on urinary histamine excretion were measured. Certain vegetables (spinach, eggplant), cheeses (Parmesan, blue, Roquefort), and red wines (Chianti and Burgundy) had a high content of histamine. Although only 0.21% of the ingested histamine was excreted unchanged in the urine, the histamine content of some of the foods was so high (Parmesan cheese, 185 micrograms/g; spinach, 60 micrograms/g; baked eggplant, 26 micrograms/g) that they caused histaminuria. Patients collecting urine for analysis for 24-hour histamine excretion for diagnosis of systemic mastocytosis or carcinoid syndrome should avoid intake of these foods and beverages on the day of the urine collection.

  8. Basic Concepts in G-Protein-Coupled Receptor Homo- and Heterodimerization

    Directory of Open Access Journals (Sweden)

    Rafael Franco

    2007-01-01

    Full Text Available Until recently, heptahelical G-protein-coupled receptors (GPCRs were considered to be expressed as monomers on the cell surface of neuronal and non-neuronal cells. It is now becoming evident that this view must be overtly changed since these receptors can form homodimers, heterodimers, and higher-order oligomers on the plasma membrane. Here we discuss some of the basics and some new concepts of receptor homo- and heteromerization. Dimers-oligomers modify pharmacology, trafficking, and signaling of receptors. First of all, GPCR dimers must be considered as the main molecules that are targeted by neurotransmitters or by drugs. Thus, binding data must be fitted to dimer-based models. In these models, it is considered that the conformational changes transmitted within the dimer molecule lead to cooperativity. Cooperativity must be taken into account in the binding of agonists-antagonists-drugs and also in the binding of the so-called allosteric modulators. Cooperativity results from the intramolecular cross-talk in the homodimer. As an intramolecular cross-talk in the heterodimer, the binding of one neurotransmitter to one receptor often affects the binding of the second neurotransmitter to the partner receptor. Coactivation of the two receptors in a heterodimer can change completely the signaling pathway triggered by the neurotransmitter as well as the trafficking of the receptors. Heterodimer-specific drugs or dual drugs able to activate the two receptors in the heterodimer simultaneously emerge as novel and promising drugs for a variety of central nervous system (CNS therapeutic applications.

  9. Improved methodical approach for quantitative BRET analysis of G Protein Coupled Receptor dimerization.

    Directory of Open Access Journals (Sweden)

    Bence Szalai

    Full Text Available G Protein Coupled Receptors (GPCR can form dimers or higher ordered oligomers, the process of which can remarkably influence the physiological and pharmacological function of these receptors. Quantitative Bioluminescence Resonance Energy Transfer (qBRET measurements are the gold standards to prove the direct physical interaction between the protomers of presumed GPCR dimers. For the correct interpretation of these experiments, the expression of the energy donor Renilla luciferase labeled receptor has to be maintained constant, which is hard to achieve in expression systems. To analyze the effects of non-constant donor expression on qBRET curves, we performed Monte Carlo simulations. Our results show that the decrease of donor expression can lead to saturation qBRET curves even if the interaction between donor and acceptor labeled receptors is non-specific leading to false interpretation of the dimerization state. We suggest here a new approach to the analysis of qBRET data, when the BRET ratio is plotted as a function of the acceptor labeled receptor expression at various donor receptor expression levels. With this method, we were able to distinguish between dimerization and non-specific interaction when the results of classical qBRET experiments were ambiguous. The simulation results were confirmed experimentally using rapamycin inducible heterodimerization system. We used this new method to investigate the dimerization of various GPCRs, and our data have confirmed the homodimerization of V2 vasopressin and CaSR calcium sensing receptors, whereas our data argue against the heterodimerization of these receptors with other studied GPCRs, including type I and II angiotensin, β2 adrenergic and CB1 cannabinoid receptors.

  10. The amphioxus (Branchiostoma floridae genome contains a highly diversified set of G protein-coupled receptors

    Directory of Open Access Journals (Sweden)

    Schiöth Helgi B

    2008-01-01

    Full Text Available Abstract Background G protein-coupled receptors (GPCRs are one of the largest families of genes in mammals. Branchiostoma floridae (amphioxus is one of the species most closely related species to vertebrates. Results Mining and phylogenetic analysis of the amphioxus genome showed the presence of at least 664 distinct GPCRs distributed among all the main families of GPCRs; Glutamate (18, Rhodopsin (570, Adhesion (37, Frizzled (6 and Secretin (16. Surprisingly, the Adhesion GPCR repertoire in amphioxus includes receptors with many new domains not previously observed in this family. We found many Rhodopsin GPCRs from all main groups including many amine and peptide binding receptors and several previously uncharacterized expansions were also identified. This genome has however no genes coding for bitter taste receptors (TAS2, the sweet and umami (TAS1, pheromone (VR1 or VR2 or mammalian olfactory receptors. Conclusion The amphioxus genome is remarkably rich in various GPCR subtypes while the main GPCR groups known to sense exogenous substances (such as Taste 2, mammalian olfactory, nematode chemosensory, gustatory, vomeronasal and odorant receptors in other bilateral species are absent.

  11. Cloning of human genes encoding novel G protein-coupled receptors

    Energy Technology Data Exchange (ETDEWEB)

    Marchese, A.; Docherty, J.M.; Heiber, M. [Univ. of Toronto, (Canada)] [and others

    1994-10-01

    We report the isolation and characterization of several novel human genes encoding G protein-coupled receptors. Each of the receptors contained the familiar seven transmembrane topography and most closely resembled peptide binding receptors. Gene GPR1 encoded a receptor protein that is intronless in the coding region and that shared identity (43% in the transmembrane regions) with the opioid receptors. Northern blot analysis revealed that GPR1 transcripts were expressed in the human hippocampus, and the gene was localized to chromosome 15q21.6. Gene GPR2 encoded a protein that most closely resembled an interleukin-8 receptor (51% in the transmembrane regions), and this gene, not expressed in the six brain regions examined, was localized to chromosome 17q2.1-q21.3. A third gene, GPR3, showed identity (56% in the transmembrane regions) with a previously characterized cDNA clone from rat and was localized to chromosome 1p35-p36.1. 31 refs., 5 figs., 1 tab.

  12. Complete Reversible Refolding of a G-Protein Coupled Receptor on a Solid Support.

    Directory of Open Access Journals (Sweden)

    Natalie Di Bartolo

    Full Text Available The factors defining the correct folding and stability of integral membrane proteins are poorly understood. Folding of only a few select membrane proteins has been scrutinised, leaving considerable deficiencies in knowledge for large protein families, such as G protein coupled receptors (GPCRs. Complete reversible folding, which is problematic for any membrane protein, has eluded this dominant receptor family. Moreover, attempts to recover receptors from denatured states are inefficient, yielding at best 40-70% functional protein. We present a method for the reversible unfolding of an archetypal family member, the β1-adrenergic receptor, and attain 100% recovery of the folded, functional state, in terms of ligand binding, compared to receptor which has not been subject to any unfolding and retains its original, folded structure. We exploit refolding on a solid support, which could avoid unwanted interactions and aggregation that occur in bulk solution. We determine the changes in structure and function upon unfolding and refolding. Additionally, we employ a method that is relatively new to membrane protein folding; pulse proteolysis. Complete refolding of β1-adrenergic receptor occurs in n-decyl-β-D-maltoside (DM micelles from a urea-denatured state, as shown by regain of its original helical structure, ligand binding and protein fluorescence. The successful refolding strategy on a solid support offers a defined method for the controlled refolding and recovery of functional GPCRs and other membrane proteins that suffer from instability and irreversible denaturation once isolated from their native membranes.

  13. A Coupled Phase-Temperature Model for Dynamics of Transient Neuronal Signal in Mammals Cold Receptor

    Directory of Open Access Journals (Sweden)

    Firman Ahmad Kirana

    2016-01-01

    Full Text Available We propose a theoretical model consisting of coupled differential equation of membrane potential phase and temperature for describing the neuronal signal in mammals cold receptor. Based on the results from previous work by Roper et al., we modified a nonstochastic phase model for cold receptor neuronal signaling dynamics in mammals. We introduce a new set of temperature adjusted functional parameters which allow saturation characteristic at high and low steady temperatures. The modified model also accommodates the transient neuronal signaling process from high to low temperature by introducing a nonlinear differential equation for the “effective temperature” changes which is coupled to the phase differential equation. This simple model can be considered as a candidate for describing qualitatively the physical mechanism of the corresponding transient process.

  14. The Effect of Subchronic Dosing of Ciproxifan and Clobenpropit on Dopamine and Histamine Levels in Rats

    Directory of Open Access Journals (Sweden)

    D. Mahmood

    2015-01-01

    Full Text Available The present study was designed to investigate the effect of once daily for 7-day (subchronic treatment dosing of histamine H 3 receptor antagonists, ciproxifan (CPX (3 mg/kg, i.p., and clobenpropit (CBP (15 mg/kg, i.p, including clozapine (CLZ (3.0 mg/kg, i.p. and chlorpromazine (CPZ (3.0 mg/kg, i.p., the atypical and typical antipsychotic, respectively, on MK-801(0.2 mg/kg, i.p.-induced locomotor activity, and dopamine and histamine levels in rats. Dopamine and histamine levels were measured in striatum and hypothalamus, respectively, of rat brain. Atypical and typical antipsychotics were used to serve as clinically relevant reference agents to compare the effects of the H 3 receptor antagonists. MK-801-induced increase of horizontal activity was reduced with CPX and CBP. The attenuation of MK-801-induced locomotor hyperactivity produced by CPX and CBP was comparable to CLZ and CPZ. MK-801 raised dopamine levels in the striatum, which was reduced in rats pretreated with CPX and CBP. CPZ also lowered striatal dopamine levels, though the decrease was less robust compared to CLZ, CPX and CBP. MK-801 increased histamine content although to a lesser degree. Subchronic treatment with CPX and CBP exhibited further increase in histamine levels in the hypothalamus compared to the MK-801 treatment alone. Histamine H 3 receptor agonist, R-OC methylhistamine (10 mg/kg, i.p. counteracted the effects of CPX and CBP. In conclusion, the subchronic dosing of CPX/CBP suggests some antipsychotic-like activities as CPX/CBP counteracts the modulatory effects of MK-801 on dopamine and histamine levels and prevents MK-801-induced hyperlocomotor behaviors.

  15. Effects of antihistamine on up-regulation of histamine H1 receptor mRNA in the nasal mucosa of patients with pollinosis induced by controlled cedar pollen challenge in an environmental exposure unit

    Directory of Open Access Journals (Sweden)

    Yoshiaki Kitamura

    2015-11-01

    Full Text Available In the present study, we examined the effects of antihistamine on the up-regulation of H1R mRNA in the nasal mucosa of patients with pollinosis induced by controlled exposure to pollen using an environmental exposure unit. Out of 20 patients, we designated 14 responders, whose levels of H1R mRNA in the nasal mucosa were increased after the first pollen exposure and excluded 6 non-responders. Accordingly, the first exposure to pollen without treatment significantly induced both nasal symptoms and the up-regulation of H1R mRNA in the nasal mucosa of the responders. Subsequently, prophylactic administration of antihistamine prior to the second pollen exposure significantly inhibited both of the above effects in the responders. Moreover, the nasal expression of H1R mRNA before the second pollen exposure in the responders pretreated with antihistamine was significantly decreased, as compared with that before the first pollen exposure without treatment. These findings suggest that antihistamines suppressed histamine-induced transcriptional activation of H1R gene in the nasal mucosa, in addition to their blocking effect against histamine on H1R, resulting in a decrease of nasal symptoms. These findings further suggest that by their inverse agonistic activity, antihistamines suppress the basal transcription of nasal H1R in the absence of histamine in responders.

  16. Effects of antihistamine on up-regulation of histamine H1 receptor mRNA in the nasal mucosa of patients with pollinosis induced by controlled cedar pollen challenge in an environmental exposure unit.

    Science.gov (United States)

    Kitamura, Yoshiaki; Nakagawa, Hideyuki; Fujii, Tatsuya; Sakoda, Takema; Enomoto, Tadao; Mizuguchi, Hiroyuki; Fukui, Hiroyuki; Takeda, Noriaki

    2015-11-01

    In the present study, we examined the effects of antihistamine on the up-regulation of H1R mRNA in the nasal mucosa of patients with pollinosis induced by controlled exposure to pollen using an environmental exposure unit. Out of 20 patients, we designated 14 responders, whose levels of H1R mRNA in the nasal mucosa were increased after the first pollen exposure and excluded 6 non-responders. Accordingly, the first exposure to pollen without treatment significantly induced both nasal symptoms and the up-regulation of H1R mRNA in the nasal mucosa of the responders. Subsequently, prophylactic administration of antihistamine prior to the second pollen exposure significantly inhibited both of the above effects in the responders. Moreover, the nasal expression of H1R mRNA before the second pollen exposure in the responders pretreated with antihistamine was significantly decreased, as compared with that before the first pollen exposure without treatment. These findings suggest that antihistamines suppressed histamine-induced transcriptional activation of H1R gene in the nasal mucosa, in addition to their blocking effect against histamine on H1R, resulting in a decrease of nasal symptoms. These findings further suggest that by their inverse agonistic activity, antihistamines suppress the basal transcription of nasal H1R in the absence of histamine in responders. Copyright © 2015 Japanese Pharmacological Society. Production and hosting by Elsevier B.V. All rights reserved.

  17. Crystal structure of the human beta2 adrenergic G-protein-coupled receptor

    DEFF Research Database (Denmark)

    Rasmussen, Søren Gøgsig Faarup; Choi, Hee-Jung; Rosenbaum, Daniel M

    2007-01-01

    Structural analysis of G-protein-coupled receptors (GPCRs) for hormones and neurotransmitters has been hindered by their low natural abundance, inherent structural flexibility, and instability in detergent solutions. Here we report a structure of the human beta2 adrenoceptor (beta2AR), which....... These differences may be responsible for the relatively high basal activity and structural instability of the beta2AR, and contribute to the challenges in obtaining diffraction-quality crystals of non-rhodopsin GPCRs....

  18. Heterologous production, characterization and isolation of selected G protein-coupled receptors for structural studies

    OpenAIRE

    Shukla, Arun Kumar

    2006-01-01

    G protein-coupled receptors (GPCRs) play regulatory roles in many different physiological processes and they represent one of the most important class of drug targets. However, due to the lack of three-dimensional structures, structure based drug design has not been possible. The major bottleneck in getting three-dimensional crystal structure of GPCRs is to obtain milligram quantities of pure, homogenous and stable protein. Therefore, during my Ph.D. thesis, I focused on expression, character...

  19. Biochemical and Cellular Specificity of Peptide Inhibitors of G Protein-Coupled Receptor Kinases

    OpenAIRE

    Baameur, Faiza; Hammitt, Richard A.; Friedman, Jacqueline; McMurray, John S.; Clark, Richard B

    2014-01-01

    Identifying novel allosteric inhibitors of G protein-coupled receptor kinases (GRKs) would be of considerable use in limiting both the extent of desensitization of GPCRs as well as downstream positive regulation through GRKs. Several peptides have previously been identified as inhibitors of specific GRKs, but to date there have been few comparisons of the selectivities of these materials on the seven GRKs, modifications to allow cell penetration, or off-target activities. The goal of this stu...

  20. From atomic structures to neuronal functions of g protein-coupled receptors.

    Science.gov (United States)

    Palczewski, Krzysztof; Orban, Tivadar

    2013-07-08

    G protein-coupled receptors (GPCRs) are essential mediators of signal transduction, neurotransmission, ion channel regulation, and other cellular events. GPCRs are activated by diverse stimuli, including light, enzymatic processing of their N-termini, and binding of proteins, peptides, or small molecules such as neurotransmitters. GPCR dysfunction caused by receptor mutations and environmental challenges contributes to many neurological diseases. Moreover, modern genetic technology has helped identify a rich array of mono- and multigenic defects in humans and animal models that connect such receptor dysfunction with disease affecting neuronal function. The visual system is especially suited to investigate GPCR structure and function because advanced imaging techniques permit structural studies of photoreceptor neurons at both macro and molecular levels that, together with biochemical and physiological assessment in animal models, provide a more complete understanding of GPCR signaling.

  1. Signal Transduction of Sphingosine-1-Phosphate G Protein—Coupled Receptors

    Directory of Open Access Journals (Sweden)

    Nicholas Young

    2006-01-01

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive lipid capable of eliciting dramatic effects in a variety of cell types. Signaling by this molecule is by a family of five G protein—coupled receptors named S1P1–5 that signal through a variety of pathways to regulate cell proliferation, migration, cytoskeletal organization, and differentiation. These receptors are expressed in a wide variety of tissues and cell types, and their cellular effects contribute to important biological and pathological functions of S1P in many processes, including angiogenesis, vascular development, lymphocyte trafficking, and cancer. This review will focus on the current progress in the field of S1P receptor signaling and biology.

  2. Evolution of a G protein-coupled receptor response by mutations in regulatory network interactions

    DEFF Research Database (Denmark)

    Di Roberto, Raphaël B; Chang, Belinda; Trusina, Ala

    2016-01-01

    All cellular functions depend on the concerted action of multiple proteins organized in complex networks. To understand how selection acts on protein networks, we used the yeast mating receptor Ste2, a pheromone-activated G protein-coupled receptor, as a model system. In Saccharomyces cerevisiae......, Ste2 is a hub in a network of interactions controlling both signal transduction and signal suppression. Through laboratory evolution, we obtained 21 mutant receptors sensitive to the pheromone of a related yeast species and investigated the molecular mechanisms behind this newfound sensitivity. While...... some mutants show enhanced binding affinity to the foreign pheromone, others only display weakened interactions with the network's negative regulators. Importantly, the latter changes have a limited impact on overall pathway regulation, despite their considerable effect on sensitivity. Our results...

  3. G protein-coupled receptors as new therapeutic targets for type 2 diabetes.

    Science.gov (United States)

    Reimann, Frank; Gribble, Fiona M

    2016-02-01

    G protein-coupled receptors (GPCRs) in the gut-brain-pancreatic axis are key players in the postprandial control of metabolism and food intake. A number of intestinally located receptors have been implicated in the chemo-detection of ingested nutrients, and in the pancreatic islets and nervous system GPCRs play essential roles in the detection of many hormones and neurotransmitters. Because of the diversity, cell-specific expression and 'druggability' of the GPCR superfamily, these receptors are popular targets for therapeutic development. This review will outline current and potential future approaches to develop GPCR agonists for the treatment of type 2 diabetes. This review summarises a presentation given at the 'Novel approaches to treating type 2 diabetes' symposium at the 2015 annual meeting of the EASD. It is accompanied by a commentary by the Session Chair, Michael Nauck (DOI: 10.1007/s00125-015-3823-1 ).

  4. Membrane-Mediated Oligomerization of G Protein Coupled Receptors and Its Implications for GPCR Function.

    Science.gov (United States)

    Gahbauer, Stefan; Böckmann, Rainer A

    2016-01-01

    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-signaling 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.

  5. Role and therapeutic potential of G-protein coupled receptors in breast cancer progression and metastases.

    Science.gov (United States)

    Singh, Anukriti; Nunes, Jessica J; Ateeq, Bushra

    2015-09-15

    G-protein-coupled receptors (GPCRs) comprise a large family of cell-surface receptors, which have recently emerged as key players in tumorigenesis, angiogenesis and metastasis. In this review, we discussed our current understanding of the many roles played by GPCRs in general, and particularly Angiotensin II type I receptor (AGTR1), a member of the seven-transmembrane-spanning G-protein coupled receptor superfamily, and its significance in breast cancer progression and metastasis. We have also discussed different strategies for targeting AGTR1, and its ligand Angiotension II (Ang II), which might unravel unique opportunities for breast cancer prevention and treatment. For example, AGTR1 blockers (ARBs) which are already in clinical use for treating hypertension, merit further investigation as a therapeutic strategy for AGTR1-positive cancer patients and may have the potential to prevent Ang II-AGTR1 signalling mediated cancer pathogenesis and metastases. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  6. Targeting of vasoactive intestinal peptide receptor 2, VPAC2, a secretin family G-protein coupled receptor, to primary cilia

    Directory of Open Access Journals (Sweden)

    Livana Soetedjo

    2013-05-01

    Primary cilia protrude from the cell surface of many cell types in the human body and function as cellular antennae via ciliary membrane localized receptors. Neurons and glial cells in the brain possess primary cilia, and the malfunction of primary cilia may contribute to neurological deficits present in many cilia-associated disorders. Several rhodopsin family G-protein coupled receptors (GPCRs are specifically localized to a subset of neuronal primary cilia. However, whether other family GPCRs target to neuronal cilia and whether glial primary cilia harbor any GPCRs are not known. We conducted a screening of GPCRs to determine their ability to target to primary cilia, and identified a secretin family member, Vasoactive Intestinal Receptor 2 (VPAC2, as a novel ciliary GPCR. Here, we show that endogenous VPAC2 targets to primary cilia in various brain regions, including the suprachiasmatic nuclei and the thalamus. Surprisingly, VPAC2 not only localizes to neuronal cilia but also to glial cilia. In addition, we show that VPAC2's C-terminus is both necessary and sufficient for its ciliary targeting and we define a novel ciliary targeting signal: the tetrapeptide RDYR motif in the C-terminus of VPAC2. Furthermore, we demonstrate that VPAC2 ciliary targeting is dependent on Tubby, the BBSome (a complex of Bardet–Biedl syndrome proteins and the BBSome targeting factor, Arl6.

  7. Histamine deficiency exacerbates myocardial injury in acute myocardial infarction through impaired macrophage infiltration and increased cardiomyocyte apoptosis

    Science.gov (United States)

    Deng, Long; Hong, Tao; Lin, Jinyi; Ding, Suling; Huang, Zheyong; Chen, Jinmiao; Jia, Jianguo; Zou, Yunzeng; Wang, Timothy C.; Yang, Xiangdong; Ge, Junbo

    2015-01-01

    Histamine is a biogenic amine that is widely distributed and has multiple functions, but the role it plays in acute myocardial infarction (AMI) remains unclear. In this study, we investigated the origin and contribution of endogenous histamine to AMI. Histidine decarboxylase (HDC) is the unique enzyme responsible for histamine generation. Using HDC-EGFP bacterial artificial chromosome (BAC) transgenic mice in which EGFP expression is controlled by the HDC promoter, we identified HDC expression primarily in CD11b+Gr-1+ immature myeloid cells (IMCs) that markedly increase in the early stages of AMI. Deficiency of histamine in HDC knockout mice (HDC−/−) reduced cardiac function and exacerbated the injury of infarcted heart. Furthermore, administering either an H1 receptor antagonist (pyrilamine) or an H2 receptor antagonist (cimetidine) demonstrated a protective effect of histamine against myocardial injury. The results of in vivo and in vitro assays showed that histamine deficiency promotes the apoptosis of cardiomyocytes and inhibits macrophage infiltration. In conclusion, CD11b+Gr-1+ IMCs are the predominant HDC-expressing sites in AMI, and histamine plays a protective role in the process of AMI through inhibition of cardiomyocyte apoptosis and facilitation of macrophage infiltration. PMID:26278136

  8. Effect of histamine on the electrophysiology of the human parietal pleura.

    Science.gov (United States)

    Kouritas, V K; Tsantsaridou, A; Tepetes, K; Tsilimingas, N; Gourgoulianis, K I; Molyvdas, P A; Hatzoglou, C

    2011-01-30

    Histamine is involved in the pathogenesis of numerous diseases and regulates the permeability of different tissues. The aim of this study is to investigate the effects of histamine on the electrophysiology of human parietal pleura and the underlying mechanisms involved. Pleural specimens were obtained from patients subjected to thoracic surgery and were mounted in Ussing chambers. Histamine solutions (1μM to 1mM) were applied in native and pretreated specimens with dimetindene maleate, cetirizine, ranitidine, amiloride and ouabain. Trans-mesothelial resistance was determined (R(TM)). Histamine induced a rapid R(TM) increase on the mesothelial (p = 0.008) and a decrease on the interstitial surface (p = 0.029). This effect was dose-dependent and was totally abolished by dimetindene maleate, cetirizine and amiloride and partially by ranitidine and ouabain. Histamine induces acute electrochemical changes in human pleura mainly via interaction with the H(1) and partially with the H(2) histamine receptors. It also interferes with trans-cellular permeability and therefore may participate in pleural fluid recycling. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  9. Quantitative electrophysiological monitoring of anti-histamine drug effects on live cells via reusable sensor platforms.

    Science.gov (United States)

    Pham Ba, Viet Anh; Cho, Dong-Guk; Kim, Daesan; Yoo, Haneul; Ta, Van-Thao; Hong, Seunghun

    2017-08-15

    We demonstrated the quantitative electrophysiological monitoring of histamine and anti-histamine drug effects on live cells via reusable sensor platforms based on carbon nanotube transistors. This method enabled us to monitor the real-time electrophysiological responses of a single HeLa cell to histamine with different concentrations. The measured electrophysiological responses were attributed to the activity of histamine type 1 receptors on a HeLa cell membrane by histamine. Furthermore, the effects of anti-histamine drugs such as cetirizine or chlorphenamine on the electrophysiological activities of HeLa cells were also evaluated quantitatively. Significantly, we utilized only a single device to monitor the responses of multiple HeLa cells to each drug, which allowed us to quantitatively analyze the antihistamine drug effects on live cells without errors from the device-to-device variation in device characteristics. Such quantitative evaluation capability of our method would promise versatile applications such as drug screening and nanoscale bio sensor researches. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Effects of the novel histamine H2-receptor antagonist (+/-)-(E)-1-[2-hydroxy-2-(4-hydroxyphenyl)ethyl]-3-[2-[[[5- (methylamino)methyl-2-furyl]methyl]thio]ethyl]-2-(methylsulfonyl) guanidine on gastric secretion and gastroduodenal ulcers in rats.

    Science.gov (United States)

    Amagase, K; Kato, S; Yamamoto, H; Okabe, S

    1996-02-01

    The effects of (+/-)-(E)-1-[2-hydroxy-2-(4-hydroxyphenyl)ethyl]-3-[2- [[[5-(methylamino)methyl-2-furyl] methyl]thio]ethyl]-2-(methylsulfonyl)guanidine (CAS 140695-21-2, T-593), a new histamine H2-receptor antagonist, on gastric secretion and experimental gastric and duodenal lesion/ulcer models in rats were examined. The drug administered orally or intraduodenally significantly and dose-dependently inhibited both basal and histamine-stimulated acid secretion. Pepsin output was also inhibited by the drug nearly dose-dependently. The acid-inhibitory effect of T-593 persisted for 12 h after a single oral administration. T-593 potently protected the gastric mucosa against water-immersion stress-, indometacin- and HCl.acetylsalicylic acid-induced lesions, but it had no effect on HCl.ethanol-induced lesions. T-593 significantly prevented the development of mepirizole-induced duodenal ulcers. Spontaneous healing of kissing gastric ulcers was significantly enhanced when T-593 was administered for 14 days. The antisecretory and antilesion/antiulcer effects of T-593 were similar to those of ranitidine and omeprazole. It is concluded that T-593 is a potent antisecretory and antiulcer drug.

  11. Integrating Pharmacophore into Membrane Molecular Dynamics Simulations to Improve Homology Modeling of G Protein-coupled Receptors with Ligand Selectivity: A2A Adenosine Receptor as an Example.

    Science.gov (United States)

    Zeng, Lingxiao; Guan, Mengxin; Jin, Hongwei; Liu, Zhenming; Zhang, Liangren

    2015-12-01

    Homology modeling has been applied to fill in the gap in experimental G protein-coupled receptors structure determination. However, achievement of G protein-coupled receptors homology models with ligand selectivity remains challenging due to structural diversity of G protein-coupled receptors. In this work, we propose a novel strategy by integrating pharmacophore and membrane molecular dynamics (MD) simulations to improve homology modeling of G protein-coupled receptors with ligand selectivity. To validate this integrated strategy, the A2A adenosine receptor (A2A AR), whose structures in both active and inactive states have been established, has been chosen as an example. We performed blind predictions of the active-state A2A AR structure based on the inactive-state structure and compared the performance of different refinement strategies. The blind prediction model combined with the integrated strategy identified ligand-receptor interactions and conformational changes of key structural elements related to the activation of A2 A AR, including (i) the movements of intracellular ends of TM3 and TM5/TM6; (ii) the opening of ionic lock; (iii) the movements of binding site residues. The integrated strategy of pharmacophore with molecular dynamics simulations can aid in the optimization in the identification of side chain conformations in receptor models. This strategy can be further investigated in homology modeling and expand its applicability to other G protein-coupled receptor modeling, which should aid in the discovery of more effective and selective G protein-coupled receptor ligands. © 2015 John Wiley & Sons A/S.

  12. Molecular recognition of parathyroid hormone by its G protein-coupled receptor

    Energy Technology Data Exchange (ETDEWEB)

    Pioszak, Augen A.; Xu, H. Eric (Van Andel)

    2008-08-07

    Parathyroid hormone (PTH) is central to calcium homeostasis and bone maintenance in vertebrates, and as such it has been used for treating osteoporosis. It acts primarily by binding to its receptor, PTH1R, a member of the class B G protein-coupled receptor (GPCR) family that also includes receptors for glucagon, calcitonin, and other therapeutically important peptide hormones. Despite considerable interest and much research, determining the structure of the receptor-hormone complex has been hindered by difficulties in purifying the receptor and obtaining diffraction-quality crystals. Here, we present a method for expression and purification of the extracellular domain (ECD) of human PTH1R engineered as a maltose-binding protein (MBP) fusion that readily crystallizes. The 1.95-{angstrom} structure of PTH bound to the MBP-PTH1R-ECD fusion reveals that PTH docks as an amphipathic helix into a central hydrophobic groove formed by a three-layer {alpha}-{beta}-{beta}{alpha} fold of the PTH1R ECD, resembling a hot dog in a bun. Conservation in the ECD scaffold and the helical structure of peptide hormones emphasizes this hot dog model as a general mechanism of hormone recognition common to class B GPCRs. Our findings reveal critical insights into PTH actions and provide a rational template for drug design that targets this hormone signaling pathway.

  13. Functional and Structural Overview of G-Protein-Coupled Receptors Comprehensively Obtained from Genome Sequences

    Directory of Open Access Journals (Sweden)

    Makiko Suwa

    2011-04-01

    Full Text Available An understanding of the functional mechanisms of G-protein-coupled receptors (GPCRs is very important for GPCR-related drug design. We have developed an integrated GPCR database (SEVENS http://sevens.cbrc.jp/ that includes 64,090 reliable GPCR genes comprehensively identified from 56 eukaryote genome sequences, and overviewed the sequences and structure spaces of the GPCRs. In vertebrates, the number of receptors for biological amines, peptides, etc. is conserved in most species, whereas the number of chemosensory receptors for odorant, pheromone, etc. significantly differs among species. The latter receptors tend to be single exon type or a few exon type and show a high ratio in the numbers of GPCRs, whereas some families, such as Class B and Class C receptors, have long lengths due to the presence of many exons. Statistical analyses of amino acid residues reveal that most of the conserved residues in Class A GPCRs are found in the cytoplasmic half regions of transmembrane (TM helices, while residues characteristic to each subfamily found on the extracellular half regions. The 69 of Protein Data Bank (PDB entries of complete or fragmentary structures could be mapped on the TM/loop regions of Class A GPCRs covering 14 subfamilies.

  14. Comprehensive Analysis of Non-Synonymous Natural Variants of G Protein-Coupled Receptors.

    Science.gov (United States)

    Kim, Hee Ryung; Duc, Nguyen Minh; Chung, Ka Young

    2017-09-19

    G protein-coupled receptors (GPCRs) are the largest superfamily of transmembrane receptors and have vital signaling functions in various organs. Because of their critical roles in physiology and pathology, GPCRs are the most commonly used therapeutic target. It has been suggested that GPCRs undergo massive genetic variations such as genetic polymorphisms and DNA insertions or deletions. Among these genetic variations, non-synonymous natural variations change the amino acid sequence and could thus alter GPCR functions such as expression, localization, signaling, and ligand binding, which may be involved in disease development and altered responses to GPCR-targeting drugs. Despite the clinical importance of GPCRs, studies on the genotype-phenotype relationship of GPCR natural variants have been limited to a few GPCRs such as β-adrenergic receptors and opioid receptors. Comprehensive understanding of non-synonymous natural variations within GPCRs would help to predict the unknown genotype-phenotype relationship and yet-to-be-discovered natural variants. Here, we analyzed the non-synonymous natural variants of all non-olfactory GPCRs available from a public database, UniProt. The results suggest that non-synonymous natural variations occur extensively within the GPCR superfamily especially in the N-terminus and transmembrane domains. Within the transmembrane domains, natural variations observed more frequently in the conserved residues, which leads to disruption of the receptor function. Our analysis also suggests that only few non-synonymous natural variations have been studied in efforts to link the variations with functional consequences.

  15. Molecular recognition of ketamine by a subset of olfactory G protein–coupled receptors

    Science.gov (United States)

    Saven, Jeffery G.; Matsunami, Hiroaki; Eckenhoff, Roderic G.

    2015-01-01

    Ketamine elicits various neuropharmacological effects, including sedation, analgesia, general anesthesia, and antidepressant activity. Through an in vitro screen, we identified four mouse olfactory receptors (ORs) that responded to ketamine. In addition to their presence in the olfactory epithelium, these G protein (heterotrimeric guanine nucleotide–binding protein)–coupled receptors (GPCRs) are distributed throughout the central nervous system. To better understand the molecular basis of the interactions between ketamine and ORs, we used sequence comparison and molecular modeling to design mutations that (i) increased, reduced, or abolished ketamine responsiveness in responding receptors, and (ii) rendered non-responding receptors responsive to ketamine. We showed that olfactory sensory neurons (OSNs) that expressed distinct ORs responded to ketamine in vivo, suggesting that ORs may serve as functional targets for ketamine. The ability to both abolish and introduce responsiveness to ketamine in GPCRs enabled us to identify and confirm distinct interaction loci in the binding site, which suggested a signature ketamine-binding pocket that may guide exploration of additional receptors for this general anesthetic drug. PMID:25829447

  16. The repertoire of G-protein-coupled receptors in Xenopus tropicalis

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    Hu Yinghe

    2009-06-01

    Full Text Available Abstract Background The G-protein-coupled receptor (GPCR superfamily represents the largest protein family in the human genome. These proteins have a variety of physiological functions that give them well recognized roles in clinical medicine. In Xenopus tropicalis, a widely used animal model for physiology research, the repertoire of GPCRs may help link the GPCR evolutionary history in vertebrates from teleost fish to mammals. Results We have identified 1452 GPCRs in the X. tropicalis genome. Phylogenetic analyses classified these receptors into the following seven families: Glutamate, Rhodopsin, Adhesion, Frizzled, Secretin, Taste 2 and Vomeronasal 1. Nearly 70% of X. tropicalis GPCRs are represented by the following three types of receptors thought to receive chemosensory information from the outside world: olfactory, vomeronasal 1 and vomeronasal 2 receptors. Conclusion X. tropicalis shares a more similar repertoire of GPCRs with mammals than it does with fish. An examination of the three major groups of receptors related to olfactory/pheromone detection shows that in X. tropicalis, these groups have undergone lineage specific expansion. A comparison of GPCRs in X. tropicalis, teleost fish and mammals reveals the GPCR evolutionary history in vertebrates.

  17. G protein-coupled receptor inactivation by an allosteric inverse-agonist antibody

    Science.gov (United States)

    Hino, Tomoya; Arakawa, Takatoshi; Iwanari, Hiroko; Yurugi-Kobayashi, Takami; Ikeda-Suno, Chiyo; Nakada-Nakura, Yoshiko; Kusano-Arai, Osamu; Weyand, Simone; Shimamura, Tatsuro; Nomura, Norimichi; Cameron, Alexander D.; Kobayashi, Takuya; Hamakubo, Takao; Iwata, So; Murata, Takeshi

    2011-01-01

    G protein-coupled receptors (GPCRs) are the largest class of cell-surface receptors, and these membrane proteins exist in equilibrium between inactive and active states.1-13 Conformational changes induced by extracellular ligands binding to GPCRs result in a cellular response through the activation of G-proteins. The A2A adenosine receptor (A2AAR) is responsible for regulating blood flow to the cardiac muscle and is important in the regulation of glutamate and dopamine release in the brain.14 In this study, we have successfully raised a mouse monoclonal antibody against human A2AAR that prevents agonist but not antagonist binding to the extracellular ligand-binding pocket. The structure of the A2AAR-antibody Fab fragment (Fab2838) complex reveals that the fragment, unexpectedly, recognises the intracellular surface of A2AAR and that its complementarity determining region, CDR-H3, penetrates into the receptor. CDR-H3 is located in a similar position to the G-protein C-terminal fragment in the active opsin structure1 and to the CDR-3 of the nanobody in the active β2 adrenergic receptor structure2 but locks the A2AAR in an inactive conformation. These results shed light on a novel strategy to modulate GPCR activity. PMID:22286059

  18. Phosphorylation of G Protein-Coupled Receptors: From the Barcode Hypothesis to the Flute Model.

    Science.gov (United States)

    Yang, Zhao; Yang, Fan; Zhang, Daolai; Liu, Zhixin; Lin, Amy; Liu, Chuan; Xiao, Peng; Yu, Xiao; Sun, Jin-Peng

    2017-09-01

    Seven transmembrane G protein-coupled receptors (GPCRs) are often phosphorylated at the C terminus and on intracellular loops in response to various extracellular stimuli. Phosphorylation of GPCRs by GPCR kinases and certain other kinases can promote the recruitment of arrestin molecules. The arrestins critically regulate GPCR functions not only by mediating receptor desensitization and internalization, but also by redirecting signaling to G protein-independent pathways via interactions with numerous downstream effector molecules. Accumulating evidence over the past decade has given rise to the phospho-barcode hypothesis, which states that ligand-specific phosphorylation patterns of a receptor direct its distinct functional outcomes. Our recent work using unnatural amino acid incorporation and fluorine-19 nuclear magnetic resonance ((19)F-NMR) spectroscopy led to the flute model, which provides preliminary insight into the receptor phospho-coding mechanism, by which receptor phosphorylation patterns are recognized by an array of phosphate-binding pockets on arrestin and are translated into distinct conformations. These selective conformations are recognized by various effector molecules downstream of arrestin. The phospho-barcoding mechanism enables arrestin to recognize a wide range of phosphorylation patterns of GPCRs, contributing to their diverse functions. Copyright © 2017 by The Author(s).

  19. Fluorometric determination of histamine in cheese.

    Science.gov (United States)

    Chambers, T L; Staruszkiewicz, W F

    1978-09-01

    Thirty-one samples of cheese obtained from retail outlets were analyzed for histamine, using an official AOAC fluorometric method. The types of cheese analyzed and the ranges of histamine found were: colby, 0.3--2.8; camembert, 0.4--4.2; cheddar, 1.2--5.8; gouda, 1.3--2.4; provolone, 2.0--23.5; roquefort, 1.0--16.8; mozzarella 1.6--5.0; and swiss, 0.4--250 mg histamine/100 g. Ten of the 12 samples of swiss cheese contained less than 16 mg histamine/100 g. The remaining 2 samples which contained 116 and 250 mg histamine/100 g were judged organoleptically to be of poor quality. An investigation of one processing facility showed that the production of histamine in swiss cheese may have been a result of a hydrogen peroxide/low temperature treatment of the milk supply. Recovery of histamine added to methanol extracts of cheese ranged from 93 to 105%. Histamine content was confirmed by high pressure liquid chromatographic analysis of the methanol extracts.

  20. Absence of histamine-induced itch in the African naked mole-rat and "rescue" by Substance P

    Directory of Open Access Journals (Sweden)

    Lewin Gary R

    2010-05-01

    Full Text Available Abstract Recent research has proposed a pathway in which sensory neurons expressing the capsaicin activated ion channel TRPV1 are required for histamine-induced itch and subsequent scratching behavior. We examined histamine-induced itch in the African naked mole-rat (Heterocephalus glaber and found that although naked mole-rats display innate scratching behavior, histamine was unable to evoke increased scratching as is observed in most mouse strains. Using calcium imaging, we examined the histamine sensitivity of naked mole-rat dorsal root ganglia (DRG neurons and identified a population of small diameter neurons activated by histamine, the majority of which are also capsaicin-sensitive. This suggested that naked mole-rat sensory neurons are activated by histamine, but that spinal dorsal horn processing of sensory information is not the same as in other rodents. We have previously shown that naked mole-rats naturally lack substance P (SP in cutaneous C-fibers, but that the neurokinin-1 receptor is expressed in the superficial spinal cord. This led us to investigate if SP deficiency plays a role in the lack of histamine-induced scratching in this species. After intrathecal administration of SP into the spinal cord we observed robust scratching behavior in response to histamine injection. Our data therefore support a model in which TRPV1-expressing sensory neurons are important for histamine-induced itch. In addition, we demonstrate a requirement for active, SP-induced post-synaptic drive to enable histamine sensitive afferents to drive itch-related behavior in the naked mole-rat. These results illustrate that it is altered dorsal horn connectivity of nociceptors that underlies the lack of itch and pain-related behavior in the naked mole-rat.

  1. Histamine Derived from Probiotic Lactobacillus reuteri Suppresses TNF via Modulation of PKA and ERK Signaling

    Science.gov (United States)

    Thomas, Carissa M.; Hong, Teresa; van Pijkeren, Jan Peter; Hemarajata, Peera; Trinh, Dan V.; Hu, Weidong; Britton, Robert A.; Kalkum, Markus; Versalovic, James

    2012-01-01

    Beneficial microbes and probiotic species, such as Lactobacillus reuteri, produce biologically active compounds that can modulate host mucosal immunity. Previously, immunomodulatory factors secreted by L. reuteri ATCC PTA 6475 were unknown. A combined metabolomics and bacterial genetics strategy was utilized to identify small compound(s) produced by L. reuteri that were TNF-inhibitory. Hydrophilic interaction liquid chromatography-high performance liquid chromatography (HILIC-HPLC) separation isolated TNF-inhibitory compounds, and HILIC-HPLC fraction composition was determined by NMR and mass spectrometry analyses. Histamine was identified and quantified in TNF-inhibitory HILIC-HPLC fractions. Histamine is produced from L-histidine via histidine decarboxylase by some fermentative bacteria including lactobacilli. Targeted mutagenesis of each gene present in the histidine decarboxylase gene cluster in L. reuteri 6475 demonstrated the involvement of histidine decarboxylase pyruvoyl type A (hdcA), histidine/histamine antiporter (hdcP), and hdcB in production of the TNF-inhibitory factor. The mechanism of TNF inhibition by L. reuteri-derived histamine was investigated using Toll-like receptor 2 (TLR2)-activated human monocytoid cells. Bacterial histamine suppressed TNF production via activation of the H2 receptor. Histamine from L. reuteri 6475 stimulated increased levels of cAMP, which inhibited downstream MEK/ERK MAPK signaling via protein kinase A (PKA) and resulted in suppression of TNF production by transcriptional regulation. In summary, a component of the gut microbiome, L. reuteri, is able to convert a dietary component, L-histidine, into an immunoregulatory signal, histamine, which suppresses pro-inflammatory TNF production. The identification of bacterial bioactive metabolites and their corresponding mechanisms of action with respect to immunomodulation may lead to improved anti-inflammatory strategies for chronic immune-mediated diseases. PMID:22384111

  2. Histamine derived from probiotic Lactobacillus reuteri suppresses TNF via modulation of PKA and ERK signaling.

    Directory of Open Access Journals (Sweden)

    Carissa M Thomas

    Full Text Available Beneficial microbes and probiotic species, such as Lactobacillus reuteri, produce biologically active compounds that can modulate host mucosal immunity. Previously, immunomodulatory factors secreted by L. reuteri ATCC PTA 6475 were unknown. A combined metabolomics and bacterial genetics strategy was utilized to identify small compound(s produced by L. reuteri that were TNF-inhibitory. Hydrophilic interaction liquid chromatography-high performance liquid chromatography (HILIC-HPLC separation isolated TNF-inhibitory compounds, and HILIC-HPLC fraction composition was determined by NMR and mass spectrometry analyses. Histamine was identified and quantified in TNF-inhibitory HILIC-HPLC fractions. Histamine is produced from L-histidine via histidine decarboxylase by some fermentative bacteria including lactobacilli. Targeted mutagenesis of each gene present in the histidine decarboxylase gene cluster in L. reuteri 6475 demonstrated the involvement of histidine decarboxylase pyruvoyl type A (hdcA, histidine/histamine antiporter (hdcP, and hdcB in production of the TNF-inhibitory factor. The mechanism of TNF inhibition by L. reuteri-derived histamine was investigated using Toll-like receptor 2 (TLR2-activated human monocytoid cells. Bacterial histamine suppressed TNF production via activation of the H(2 receptor. Histamine from L. reuteri 6475 stimulated increased levels of cAMP, which inhibited downstream MEK/ERK MAPK signaling via protein kinase A (PKA and resulted in suppression of TNF production by transcriptional regulation. In summary, a component of the gut microbiome, L. reuteri, is able to convert a dietary component, L-histidine, into an immunoregulatory signal, histamine, which suppresses pro-inflammatory TNF production. The identification of bacterial bioactive metabolites and their corresponding mechanisms of action with respect to immunomodulation may lead to improved anti-inflammatory strategies for chronic immune-mediated diseases.

  3. Identification of G-Protein-Coupled-Receptors (GPCRs) in Pulmonary Artery Smooth Muscle Cells as Novel Therapeutic Targets

    Science.gov (United States)

    2016-10-01

    AWARD NUMBER: W81XWH-14-1-0372 TITLE: Identification of G-Protein-Coupled Receptors (GPCRs) in Pulmonary Artery Smooth Muscle Cells as...DATES COVERED 2 Sep 2015 - 1Sep2016 4. TITLE AND SUBTITLE Identification of G-Protein-Coupled Receptors (GPCRs) in Pulmonary Artery Smooth Muscle Cells ...smooth muscle cells (PASMCs). The underlying idea of this project is that the currently limited treatments for PAH represent an unmet medical need

  4. Crosslinking photosensitized by a ruthenium chelate as a tool for labeling and topographical studies of G-protein-coupled receptors.

    Science.gov (United States)

    Duroux-Richard, Isabelle; Vassault, Philippe; Subra, Guy; Guichou, Jean-François; Richard, Eric; Mouillac, Bernard; Barberis, Claude; Marie, Jacky; Bonnafous, Jean-Claude

    2005-01-01

    The purpose was to apply oxidative crosslinking reactions to the study of recognition and signaling mechanisms associated to G-protein-coupled receptors. Using a ruthenium chelate, Ru(bipy)(3)(2+), as photosensitizer and visible light irradiation, in the presence of ammonium persulfate, we performed fast and efficient covalent labeling of the B(2) bradykinin receptor by agonist or antagonist ligands possessing a radio-iodinated phenol moiety. The chemical and topographical specificities of these crosslinking experiments were investigated. The strategy could also be applied to the covalent labeling of the B(1) bradykinin receptor, the AT(1) angiotensin II receptor, the V(1a) vasopressin receptor and the oxytocin receptor. Interestingly, we demonstrated the possibility to covalently label the AT(1) and B(2) receptors with functionalized ligands. The potential applications of metal-chelate chemistry to receptor structural and signaling studies through intramolecular or intermolecular crosslinking are presented.

  5. Induction of RAGE Shedding by Activation of G Protein-Coupled Receptors

    Science.gov (United States)

    Metz, Verena V.; Kojro, Elzbieta; Rat, Dorothea; Postina, Rolf

    2012-01-01

    The multiligand Receptor for Advanced Glycation End products (RAGE) is involved in various pathophysiological processes, including diabetic inflammatory conditions and Alzheimes disease. Full-length RAGE, a cell surface-located type I membrane protein, can proteolytically be converted by metalloproteinases ADAM10 and MMP9 into a soluble RAGE form. Moreover, administration of recombinant soluble RAGE suppresses activation of cell surface-located RAGE by trapping RAGE ligands. Therefore stimulation of RAGE shedding might have a therapeutic value regarding inflammatory diseases. We aimed to investigate whether RAGE shedding is inducible via ligand-induced activation of G protein-coupled receptors (GPCRs). We chose three different GPCRs coupled to distinct signaling cascades: the V2 vasopressin receptor (V2R) activating adenylyl cyclase, the oxytocin receptor (OTR) linked to phospholipase Cβ, and the PACAP receptor (subtype PAC1) coupled to adenylyl cyclase, phospholipase Cβ, calcium signaling and MAP kinases. We generated HEK cell lines stably coexpressing an individual GPCR and full-length RAGE and then investigated GPCR ligand-induced activation of RAGE shedding. We found metalloproteinase-mediated RAGE shedding on the cell surface to be inducible via ligand-specific activation of all analyzed GPCRs. By using specific inhibitors we have identified Ca2+ signaling, PKCα/PKCβI, CaMKII, PI3 kinases and MAP kinases to be involved in PAC1 receptor-induced RAGE shedding. We detected an induction of calcium signaling in all our cell lines coexpressing RAGE and different GPCRs after agonist treatment. However, we did not disclose a contribution of adenylyl cyclase in RAGE shedding induction. Furthermore, by using a selective metalloproteinase inhibitor and siRNA-mediated knock-down approaches, we show that ADAM10 and/or MMP9 are playing important roles in constitutive and PACAP-induced RAGE shedding. We also found that treatment of mice with PACAP increases the amount of

  6. G protein-coupled receptor kinases: more than just kinases and not only for GPCRs

    Science.gov (United States)

    Gurevich, Eugenia V.; Tesmer, John J. G.; Mushegian, Arcady; Gurevich, Vsevolod V.

    2011-01-01

    G protein-coupled receptor (GPCR) kinases (GRKs) are best known for their role in homologous desensitization of GPCRs. GRKs phosphorylate activated receptors and promote high affinity binding of arrestins, which precludes G protein coupling. GRKs have a multidomain structure, with the kinase domain inserted into a loop of a regulator of G protein signaling homology domain. Unlike many other kinases, GRKs do not need to be phosphorylated in their activation loop to achieve an activated state. Instead, they are directly activated by docking with active GPCRs. In this manner they are able to selectively phosphorylate Ser/Thr residues on only the activated form of the receptor, unlike related kinases such as protein kinase A. GRKs also phosphorylate a variety of non-GPCR substrates and regulate several signaling pathways via direct interactions with other proteins in a phosphorylation-independent manner. Multiple GRK subtypes are present in virtually every animal cell, with the highest expression levels found in neurons, with their extensive and complex signal regulation. Insufficient or excessive GRK activity was implicated in a variety of human disorders, ranging from heart failure to depression to Parkinson’s disease. As key regulators of GPCR-dependent and -independent signaling pathways, GRKs are emerging drug targets and promising molecular tools for therapy. Targeted modulation of expression and/or of activity of several GRK isoforms for therapeutic purposes was recently validated in cardiac disorders and Parkinson’s disease. PMID:21903131

  7. Reduced expression of G protein-coupled receptor kinases in schizophrenia but not in schizoaffective disorder

    Science.gov (United States)

    Bychkov, ER; Ahmed, MR; Gurevich, VV; Benovic, JL; Gurevich, EV

    2011-01-01

    Alterations of multiple G protein-mediated signaling pathways are detected in schizophrenia. G protein-coupled receptor kinases (GRKs) and arrestins terminate signaling by G protein-coupled receptors exerting powerful influence on receptor functions. Modifications of arrestin and/or GRKs expression may contribute to schizophrenia pathology. Cortical expression of arrestins and GRKs was measured postmortem in control and subjects with schizophrenia or schizoaffective disorder. Additionally, arrestin/GRK expression was determined in elderly patients with schizophrenia and age-matched control. Patients with schizophrenia, but not schizoaffective disorder, displayed reduced concentration of arrestin and GRK mRNAs and GRK3 protein. Arrestins and GRK significantly decreased with age. In elderly patients, GRK6 was reduced, with other GRKs and arrestins unchanged. Reduced cortical concentration of GRKs in schizophrenia (resembling that in aging) may result in altered G protein-dependent signaling, thus contributing to prefrontal deficits in schizophrenia. The data suggest distinct molecular mechanisms underlying schizophrenia and schizoaffective disorder. PMID:21784156

  8. Isothermal chemical denaturation to determine binding affinity of small molecules to G-protein coupled receptors.

    Science.gov (United States)

    Ross, Patrick; Weihofen, Wilhelm; Siu, Fai; Xie, Amy; Katakia, Hetal; Wright, S Kirk; Hunt, Ian; Brown, Richard K; Freire, Ernesto

    2015-03-15

    The determination of accurate binding affinities is critical in drug discovery and development. Several techniques are available for characterizing the binding of small molecules to soluble proteins. The situation is different for integral membrane proteins. Isothermal chemical denaturation has been shown to be a valuable biophysical method to determine, in a direct and label-free fashion, the binding of ligands to soluble proteins. In this study, the application of isothermal chemical denaturation was applied to an integral membrane protein, the A2a G-protein coupled receptor. Binding affinities for a set of 19 small molecule agonists/antagonists of the A2a receptor were determined and found to be in agreement with data from surface plasmon resonance and radioligand binding assays previously reported in the literature. Therefore, isothermal chemical denaturation expands the available toolkit of biophysical techniques to characterize and study ligand binding to integral membrane proteins, specifically G-protein coupled receptors in vitro. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Identification of the first surrogate agonists for the G protein-coupled receptor GPR132

    DEFF Research Database (Denmark)

    Shehata, Mohamed A.; Christensen, Hanna Belcik; Isberg, Vignir

    2015-01-01

    GPR132 is an orphan class A G protein-coupled receptor. It has been proposed to be activated by protons and to regulate apoptosis, atherosclerosis and inflammation, but these results are still preliminary. In the current work, we designed and screened a focused compound library using a β-arrestin......GPR132 is an orphan class A G protein-coupled receptor. It has been proposed to be activated by protons and to regulate apoptosis, atherosclerosis and inflammation, but these results are still preliminary. In the current work, we designed and screened a focused compound library using a β......-arrestin recruitment assay, and thereby identified the first disclosed surrogate GPR132 agonist 1 with a potency of 3.4 μM. This constitutes the first available pharmacological tool for the in vitro characterization of the orphan receptor GPR132. The testing of 32 analogs furthermore identified a number of compounds...... with lower activity – of which six were agonists and two were antagonists – that were used to construct preliminary structure–activity relationships. Docking followed by a molecular dynamics simulation of compound 1 in a structural model of GPR132 displayed the putative interactions for the key ligand...

  10. Symptoms of pseudoallergy and histamine metabolism disorders

    Directory of Open Access Journals (Sweden)

    Joanna Kacik

    2016-09-01

    Full Text Available Histamine intolerance is a poorly investigated type of hypersensitivity responsible for a number of often serious symptoms, erroneously interpreted as food allergy. Endogenous histamine originates from the histidine amino acid with the help of the histidine decarboxylase enzyme. Apart from the endogenous production histamine may be supplied to the body with food. Slow-maturing and fermenting products are characterised by particularly high levels of histamine. Some food products stimulate excessive release of histamine from stores in the body as well as containing significant amounts of it. These products include spices, herbs, dried fruits and a large group of food additives. Histamine intolerance is considered to be a condition in which the amount of histamine in the body exceeds its tolerance threshold, which leads to the development of adverse reactions. These reactions primarily include skin symptoms (pruritus, urticaria, skin reddening, acne lesions, angioedema, respiratory symptoms (nasal obstruction and watery discharge, sneezing, coughing, wheezing, gastrointestinal symptoms (abdominal cramps, diarrhoea, bloating, nervous system symptoms (headaches, fatigue, irritability, anxiety, panic attacks, cardiovascular symptoms (tachycardia, hypotension, chest pain, primary dysmenorrhoea and many more. It is estimated that nearly 1% of society is susceptible to histamine intolerance. The diagnosis of this disorder is based on observing at least two characteristic symptoms and their disappearance or improvement following histamine-free diet. A new, although not easily accessible diagnostic tool is assay for serum diamine oxidase activity, which correlates to a significant extent with symptoms of histamine intolerance. Normal activity of diamine oxidase is considered to be the amount of >80 HDU/mL, decreased activity – 40–80 HDU/mL and severely decreased activity – <40 HDU/mL. Currently the option of diamine oxidase supplementation is

  11. Leucine-rich repeat-containing G-protein-coupled receptors as markers of adult stem cells

    NARCIS (Netherlands)

    Barker, N.; Clevers, H.

    2010-01-01

    Molecular markers are used to characterize and track adult stem cells. Colon cancer research has led to the identification of 2 related receptors, leucine-rich repeat-containing, G-protein-coupled receptors (Lgr)5 and Lgr6, that are expressed by small populations of cells in a variety of adult

  12. A MIP-based biomimetic sensor for the impedimetric detection of histamine in different pH environments

    Energy Technology Data Exchange (ETDEWEB)

    Bongaers, E.; Alenus, J.; Horemans, F.; Weustenraed, A.; Cleij, T.J. [Institute for Materials Research, Hasselt University, Diepenbeek (Belgium); Lutsen, L. [IMEC, Division IMOMEC, Diepenbeek (Belgium); Vanderzande, D.; Wagner, P. [Institute for Materials Research, Hasselt University, Diepenbeek (Belgium); IMEC, Division IMOMEC, Diepenbeek (Belgium); Troost, F.J.; Brummer, R.J. [Gastroenterology and Hepatology, Department of Internal Medicine, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht (Netherlands)

    2010-04-15

    The development of novel biosensors is a rapidly growing field. Substituting the biological receptor layer from the biosensor with a synthetic receptor opens the door for the development of biomimetic sensors that are chemically and physically inert, as opposed to the sensors containing biological recognition elements. Using molecularly imprinted polymers (MIPs) the specificity and affinity of biological receptors can be mimicked. In addition, a MIP-based sensor can measure in harsh environments. Histamine occurs in harsh environments in food and bodily fluids and is chosen as the target molecule for impedimetric detection. When 10 nM histamine is present in pH neutral environments, the impedance increases 45% with respect to the impedance of the sensor without histamine. Specificity is tested with respect to histidine. The influence of the pH on the performance of the sensor is tested. In a pH range of pH 5-12 the MIPs are stable, although they exhibit a varying degree of protonation. The same holds true for the target molecule of which the protonation also varies with the pH of the solution. It is shown that the pH dependent degree of protonation of both the MIP and the histamine has a large impact on the binding of histamine to the nanocavity in the MIP. Hence, the detection of histamine by a MIP-based sensor is affected by the pH of the solution. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  13. Rapid activation of inwardly rectifying potassium channels by immobile G-protein-coupled receptors.

    Science.gov (United States)

    Lober, Robert M; Pereira, Miguel A; Lambert, Nevin A

    2006-11-29

    G-protein-coupled receptors (GPCRs) mediate slow synaptic transmission and many other effects of small molecule and peptide neurotransmitters. In the standard model of GPCR signaling, receptors and G-proteins diffuse laterally within the plane of the plasma membrane and encounter each other by random collision. This model predicts that signaling will be most efficient if both GPCRs and G-proteins are free to diffuse, thus maximizing collision frequency. However, neuronal GPCRs are often recruited to and enriched at specific synaptic locations, suggesting receptor mobility is restricted in these cells. Here, we test the hypothesis that restricting GPCR mobility impairs signaling in neurons by limiting the frequency of collisions between receptors and G-proteins. Mu-opioid receptors (MORs) were immobilized on the surface of cerebellar granule neurons by avidin-mediated cross-linking, and inwardly rectifying potassium (GIRK) channels were used as rapid indicators of G-protein activation. Mobile and immobile MORs activated GIRK channels with the same onset kinetics and agonist sensitivity in these neurons. In a heterologous expression system, GFP (green fluorescent protein)-tagged G alpha(oA) subunits remained mobile after cross-linking, but their mobility was reduced in the presence of immobile MORs, suggesting that these receptors and subunits were transiently precoupled. In addition, channel activation could be reconstituted with immobile GPCRs, G-protein heterotrimers, and GIRK channels. These results show that collision frequency is not rate-limiting for G-protein activation in CNS neurons, and are consistent with the idea that signaling components are compartmentalized or preassembled.

  14. Multiplex detection of homo- and heterodimerization of g protein-coupled receptors by proximity biotinylation.

    Science.gov (United States)

    Steel, Elisabeth; Murray, Victoria L; Liu, Allen P

    2014-01-01

    Dimerization of G protein-coupled receptors (GPCRs) represents a potential mechanism by which GPCR functions are regulated. Several resonance energy transfer (RET)-based methods have revealed GPCR homo- and heterodimerization. However, interpretation of an increase in FRET efficiency could be attributed to either dimerization/oligomerization events or conformational changes within an already dimerized/oligomerized receptor complex. Furthermore, RET-based methods can only measure pairwise dimerization, and cannot easily achieve multiplex detection. In this study, we applied proximity-based biotinylation for detecting receptor dimerization by utilizing a specific enzyme-substrate pair that are fused to GPCRs. The biotin ligase BirA is fused to CXCR4 and site-specifically biotinylates an acceptor peptide (AP) in the presence of biotin. As a test case for our newly developed assay, we have characterized the homo-dimerization of chemokine receptor CXCR4 and heterodimerization of CXCR4 with CCR2 or CCR5. The degree of biotinylation varies with the amount of GPCR-AP as well as biotinylation time. Using enzyme/substrate receptor pairs and measuring receptor biotinylation, we demonstrate that CXCR4 can homo-dimerize and hetero-dimerize with CCR2 and CCR5. The effect of CXCL12, agonist for CXCR4, was found to decrease surface biotinylation of CXCR4-AP. This effect is due to a combination of CXCR4 endocytosis and stabilization of CXCR4 homodimers. Finally, when CXCR4-AP, CCR2-AP, and CCR5-AP were expressed together, we observed CXCR4-CXCR4 homodimers and CXCR4-CCR2 and CXCR4-CCR5 heterodimers. The newly developed assay opens new opportunity for multiplex detection for GPCR homo- and heterodimerization within the same cellular context.

  15. Multiplex detection of homo- and heterodimerization of g protein-coupled receptors by proximity biotinylation.

    Directory of Open Access Journals (Sweden)

    Elisabeth Steel

    Full Text Available Dimerization of G protein-coupled receptors (GPCRs represents a potential mechanism by which GPCR functions are regulated. Several resonance energy transfer (RET-based methods have revealed GPCR homo- and heterodimerization. However, interpretation of an increase in FRET efficiency could be attributed to either dimerization/oligomerization events or conformational changes within an already dimerized/oligomerized receptor complex. Furthermore, RET-based methods can only measure pairwise dimerization, and cannot easily achieve multiplex detection. In this study, we applied proximity-based biotinylation for detecting receptor dimerization by utilizing a specific enzyme-substrate pair that are fused to GPCRs. The biotin ligase BirA is fused to CXCR4 and site-specifically biotinylates an acceptor peptide (AP in the presence of biotin. As a test case for our newly developed assay, we have characterized the homo-dimerization of chemokine receptor CXCR4 and heterodimerization of CXCR4 with CCR2 or CCR5. The degree of biotinylation varies with the amount of GPCR-AP as well as biotinylation time. Using enzyme/substrate receptor pairs and measuring receptor biotinylation, we demonstrate that CXCR4 can homo-dimerize and hetero-dimerize with CCR2 and CCR5. The effect of CXCL12, agonist for CXCR4, was found to decrease surface biotinylation of CXCR4-AP. This effect is due to a combination of CXCR4 endocytosis and stabilization of CXCR4 homodimers. Finally, when CXCR4-AP, CCR2-AP, and CCR5-AP were expressed together, we observed CXCR4-CXCR4 homodimers and CXCR4-CCR2 and CXCR4-CCR5 heterodimers. The newly developed assay opens new opportunity for multiplex detection for GPCR homo- and heterodimerization within the same cellular context.

  16. Drug discovery opportunities and challenges at G protein coupled receptors for long chain free fatty acids

    Directory of Open Access Journals (Sweden)

    Nicholas D Holliday

    2012-01-01

    Full Text Available Discovery of G protein coupled receptors for long chain free fatty acids (FFAs, FFA1 (GPR40 and GPR120, has expanded our understanding of these nutrients as signalling molecules. These receptors have emerged as important sensors for FFA levels in the circulation or the gut lumen, based on evidence from in vitro and rodent models, and an increasing number of human studies. Here we consider their promise as therapeutic targets for metabolic disease, including type 2 diabetes and obesity. FFA1 directly mediates acute FFA-induced glucose-stimulated insulin secretion in pancreatic beta-cells, while GPR120 and FFA1 trigger release of incretins from intestinal endocrine cells, and so indirectly enhance insulin secretion and promote satiety. GPR120 signalling in adipocytes and macrophages also results in insulin sensitizing and beneficial anti-inflammatory effects. Drug discovery has focussed on agonists to replicate acute benefits of FFA receptor signalling, with promising early results for FFA1 agonists in man. Controversy surrounding chronic effects of FFA1 on beta-cells illustrates that long term benefits of antagonists also need exploring. It has proved challenging to generate highly selective potent ligands for FFA1 or GPR120 subtypes, given that both receptors have hydrophobic orthosteric binding sites, which are not completely defined and have modest ligand affinity. Structure activity relationships are also reliant on functional read outs, in the absence of robust binding assays to provide direct affinity estimates. Nevertheless synthetic ligands have already helped dissect specific contributions of FFA1 and GPR120 signalling from the many possible cellular effects of FFAs. Approaches including use of fluorescent ligand binding assays, and targeting allosteric receptor sites, may improve further preclinical ligand development at these receptors, to exploit their unique potential to target multiple facets of diabetes.

  17. G protein-coupled receptors in invertebrates: a state of the art.

    Science.gov (United States)

    Meeusen, Tom; Mertens, Inge; De Loof, Arnold; Schoofs, Liliane

    2003-01-01

    G protein-coupled receptors (GPCRs) constitute one of the largest and most ancient superfamilies of membrane-spanning proteins. We focus on neuropeptide GPCRs, in particular on those of invertebrates. In general, such receptors mediate the responses of signaling molecules that constitute the highest hierarchical position in the regulation of physiological processes. Until recently, only a few of these receptors were identified in invertebrates. However, the availability of a plethora of genomic information has boosted the discovery of novel members in several invertebrate species, such as Drosophila, in which 18 neuropeptide GPCRs have been characterized. The finalization of genomic projects in other invertebrates will lead to a similar expansion of GPCR understanding. Many new insights regarding neuropeptide regulation have followed from the discovery of their cognate receptors. Furthermore, information on GPCR signaling is still fragmentary and the elucidation of these pathways in model insects such as Drosophila will lead to further insights in other species, including mammals. In this review we present the current status of what is known about invertebrate GPCRs, discuss some novel perceptions that follow from the identified members, and, finally, present some future prospects.

  18. Fluorescent knock-in mice to decipher the physiopathological role of G protein-coupled receptors.

    Directory of Open Access Journals (Sweden)

    Dominique eMassotte

    2015-01-01

    Full Text Available G protein-coupled receptors (GPCRs modulate most physiological functions but are also critically involved in numerous pathological states. Approximately a third of marketed drugs target GPCRs, which places this family of receptors in the main arena of pharmacological pre-clinical and clinical research. The complexity of GPCR function demands comprehensive appraisal in native environment to collect in-depth knowledge of receptor physiopathological roles and assess the potential of therapeutic molecules. Identifying neurons expressing endogenous GPCRs is therefore essential to locate them within functional circuits whereas GPCR visualization with subcellular resolution is required to get insight into agonist-induced trafficking. Both remain frequently poorly investigated because direct visualization of endogenous receptors is often hampered by the lack of appropriate tools. Also, monitoring intracellular trafficking requires real-time visualization to gather in-depth knowledge. In this context, knock-in mice expressing a fluorescent protein or a fluorescent version of a GPCR under the control of the endogenous promoter not only help to decipher neuroanatomical circuits but also enable real-time monitoring with subcellular resolution thus providing invaluable information on their trafficking in response to a physiological or a pharmacological challenge. This review will present the animal models and discuss their contribution to the understanding of the physiopathological role of GPCRs. We will also address the drawbacks associated with this methodological approach and browse future directions.

  19. Molecular Recognition of Corticotropin releasing Factor by Its G protein-coupled Receptor CRFR1

    Energy Technology Data Exchange (ETDEWEB)

    Pioszak, Augen A.; Parker, Naomi R.; Suino-Powell, Kelly; Xu, H. Eric (Van Andel)

    2009-01-15

    The bimolecular interaction between corticotropin-releasing factor (CRF), a neuropeptide, and its type 1 receptor (CRFR1), a class B G-protein-coupled receptor (GPCR), is crucial for activation of the hypothalamic-pituitary-adrenal axis in response to stress, and has been a target of intense drug design for the treatment of anxiety, depression, and related disorders. As a class B GPCR, CRFR1 contains an N-terminal extracellular domain (ECD) that provides the primary ligand binding determinants. Here we present three crystal structures of the human CRFR1 ECD, one in a ligand-free form and two in distinct CRF-bound states. The CRFR1 ECD adopts the alpha-beta-betaalpha fold observed for other class B GPCR ECDs, but the N-terminal alpha-helix is significantly shorter and does not contact CRF. CRF adopts a continuous alpha-helix that docks in a hydrophobic surface of the ECD that is distinct from the peptide-binding site of other class B GPCRs, thereby providing a basis for the specificity of ligand recognition between CRFR1 and other class B GPCRs. The binding of CRF is accompanied by clamp-like conformational changes of two loops of the receptor that anchor the CRF C terminus, including the C-terminal amide group. These structural studies provide a molecular framework for understanding peptide binding and specificity by the CRF receptors as well as a template for designing potent and selective CRFR1 antagonists for therapeutic applications.

  20. Not lost in translation: Emerging clinical importance of the G protein-coupled estrogen receptor GPER.

    Science.gov (United States)

    Barton, Matthias

    2016-07-01

    It has been 20years that the G protein-coupled estrogen receptor (GPER) was cloned as the orphan receptor GPR30 from multiple cellular sources, including vascular endothelial cells. Here, I will provide an overview of estrogen biology and the historical background leading to the discovery of rapid vascular estrogen signaling. I will also review the recent advances in the understanding of the mechanisms underlying GPER function, its role in physiology and disease, some of the currently available GPER-targeting drugs approved for clinical use such as SERMs (selective estrogen receptor modulators) and SERDs (selective estrogen receptor downregulators). Many of currently used drugs such as tamoxifen, raloxifene, or faslodex™/fulvestrant were discovered targeting GPER many years after they had been introduced to the clinics for entirely different purposes. This has important implications for the clinical use of these drugs and their modes of action, which I have termed 'reverse translational medicine'. In addition, environmental pollutants known as 'endocrine disruptors' have been found to bind to GPER. This article also discusses recent evidence in these areas as well as opportunities in translational clinical medicine and GPER research, including medical genetics, personalized medicine, prevention, and its theranostic use. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Metabolite-Sensing G Protein-Coupled Receptors-Facilitators of Diet-Related Immune Regulation.

    Science.gov (United States)

    Tan, Jian K; McKenzie, Craig; Mariño, Eliana; Macia, Laurence; Mackay, Charles R

    2017-04-26

    Nutrition and the gut microbiome regulate many systems, including the immune, metabolic, and nervous systems. We propose that the host responds to deficiency (or sufficiency) of dietary and bacterial metabolites in a dynamic way, to optimize responses and survival. A family of G protein-coupled receptors (GPCRs) termed the metabolite-sensing GPCRs bind to various metabolites and transmit signals that are important for proper immune and metabolic functions. Members of this family include GPR43, GPR41, GPR109A, GPR120, GPR40, GPR84, GPR35, and GPR91. In addition, bile acid receptors such as GPR131 (TGR5) and proton-sensing receptors such as GPR65 show similar features. A consistent feature of this family of GPCRs is that they provide anti-inflammatory signals; many also regulate metabolism and gut homeostasis. These receptors represent one of the main mechanisms whereby the gut microbiome affects vertebrate physiology, and they also provide a link between the immune and metabolic systems. Insufficient signaling through one or more of these metabolite-sensing GPCRs likely contributes to human diseases such as asthma, food allergies, type 1 and type 2 diabetes, hepatic steatosis, cardiovascular disease, and inflammatory bowel diseases.

  2. Persistent cAMP-signals triggered by internalized G-protein-coupled receptors.

    Directory of Open Access Journals (Sweden)

    Davide Calebiro

    2009-08-01

    Full Text Available G-protein-coupled receptors (GPCRs are generally thought to signal to second messengers like cyclic AMP (cAMP from the cell surface and to become internalized upon repeated or prolonged stimulation. Once internalized, they are supposed to stop signaling to second messengers but may trigger nonclassical signals such as mitogen-activated protein kinase (MAPK activation. Here, we show that a GPCR continues to stimulate cAMP production in a sustained manner after internalization. We generated transgenic mice with ubiquitous expression of a fluorescent sensor for cAMP and studied cAMP responses to thyroid-stimulating hormone (TSH in native, 3-D thyroid follicles isolated from these mice. TSH stimulation caused internalization of the TSH receptors into a pre-Golgi compartment in close association with G-protein alpha(s-subunits and adenylyl cyclase III. Receptors internalized together with TSH and produced downstream cellular responses that were distinct from those triggered by cell surface receptors. These data suggest that classical paradigms of GPCR signaling may need revision, as they indicate that cAMP signaling by GPCRs may occur both at the cell surface and from intracellular sites, but with different consequences for the cell.

  3. Genome wide survey of G protein-coupled receptors in Tetraodon nigroviridis

    Directory of Open Access Journals (Sweden)

    Sowdhamini Ramanathan

    2005-07-01

    Full Text Available Abstract Background The G-protein-coupled receptors (GPCRs constitute one of the largest and most ancient superfamilies of membrane proteins. They play a central role in physiological processes affecting almost all aspects of the life cycle of an organism. Availability of the complete sets of putative members of a family from diverse species provides the basis for cross genome comparative studies. Results We have defined the repertoire of GPCR superfamily of Tetraodon complement with the availability of complete sequence of the freshwater puffer fish Tetraodon nigroviridis. Almost all 466 Tetraodon GPCRs (Tnig-GPCRs identified had a clear human homologue. 189 putative human and Tetraodon GPCR orthologous pairs could be identified. Tetraodon GPCRs are classified into five GRAFS families, by phylogenetic analysis, concurrent with human GPCR classification. Conclusion Direct comparison of GPCRs in Tetraodon and human genomes displays a high level of orthology and supports large-scale gene duplications in Tetraodon. Examples of lineage specific gene expansions were also observed in opsin and odorant receptors. The human and Tetraodon GPCR sequences are analogous in terms of GPCR subfamilies but display disproportionate numbers of receptors at the subfamily level. The teleost genome with its expanded set of GPCRs provides additional and interesting comparators to study both evolution and function of these receptors.

  4. Chemical biology methods for investigating G protein-coupled receptor signaling.

    Science.gov (United States)

    Huber, Thomas; Sakmar, Thomas P

    2014-09-18

    G protein-coupled receptors (GPCRs) are targets for a quarter of prescription drugs. Despite recent progress in structural biology of GPCRs, only few key conformational states in the signal transduction process have been elucidated. Agonist ligands frequently display functional selectivity where activated receptors are biased to either G protein- or arrestin-mediated downstream signaling pathways. Selective manipulation of individual steps in the GPCR activation scheme requires precise information about the kinetics of ligand binding and the dynamics of downstream signaling. One approach is to obtain time-resolved information using receptors tagged with fluorescent or structural probes. Recent advances allow for site-specific introduction of genetically encoded unnatural amino acids into expressed GPCRs. We describe how bioorthogonal functional groups on GPCRs enable the mapping of receptor-ligand interactions and how bioorthogonal chemical reactions can be used to introduce fluorescent labels for single-molecule fluorescence applications to study the kinetics and conformational dynamics of GPCR signaling complexes ("signalosomes"). Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Identification on Histamine Content and Histamin-Forming Bacteria of Boiled Badeng Slender Tuna

    Directory of Open Access Journals (Sweden)

    Yuliana Syalviana Fatuni

    2014-11-01

    Full Text Available Pindang is a semi-dried product which relatively short lasting products. Due to the rapid formation of histamine and bacterial enzyme activities contained in the fish, it is necessary to study and identify the histamine levels either on fresh tuna or in its pindang. This study aims to analyze histamine and histamine-forming bacteria in processed pindang tuna (A. rochei. Fresh tuna (A. rochei was obtained from TPI Cisolok Palabuhanratu. The fish was processed according to pindang badeng method (20% salt added, boiled for 8 hours. The product then stored at room temperature and observed for 0,8,16,24 and 32 hours. Analysis were conducted through chemical (histamine and TVB and microbiological test (TPC, identification of bacteria, histamine levels in bacteria. The results showed that the stored pindang for 32 hours can reactivate the production of histamine and increase their levels significantly. This is consistent with the increase on the value of TVB and TPC in pindang products. Six types of histamine-forming bacteria found on pindang tuna that are P. vulgaris, H. alvei, M. Morganii, E. aerogenes, K. oxytoca, K. pneumoniae. Activity test results showed that K. pneumoniae and H. alvei form the highest and the lowest levels of histamine formation respectively.Keywords: Histamine, bacterial, boiled tuna (Auxis rochei

  6. G protein coupled receptor interactions with cholesterol deep in the membrane.

    Science.gov (United States)

    Genheden, Samuel; Essex, Jonathan W; Lee, Anthony G

    2017-02-01

    G protein coupled receptors (GPCRs) are located in membranes rich in cholesterol. The membrane spanning surfaces of GPCRs contain exposed backbone carbonyl groups and residue side chains potentially capable of forming hydrogen bonds to cholesterol molecules buried deep within the hydrophobic core of the lipid bilayer. Coarse-grained molecular dynamics (CGMD) simulations allow the observation of GPCRs in cholesterol-containing lipid bilayers for long times (50μs), sufficient to ensure equilibration of the system. We have detected a number of deep cholesterol binding sites on β2 adrenergic and A2A adenosine receptors, and shown changes in these sites on agonist binding. The requirements for binding are modest, just a potential hydrogen bond partner close to a cleft or hole in the surface. This makes it likely that similar binding sites for cholesterol will exist on other classes of membrane protein. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. International Union of Basic and Clinical Pharmacology. XCIV. Adhesion G protein-coupled receptors

    DEFF Research Database (Denmark)

    Hamann, Jörg; Aust, Gabriela; Araç, Demet

    2015-01-01

    The Adhesion family forms a large branch of the pharmacologically important superfamily of G protein-coupled receptors (GPCRs). As Adhesion GPCRs increasingly receive attention from a wide spectrum of biomedical fields, the Adhesion GPCR Consortium, together with the International Union of Basic...... and Clinical Pharmacology Committee on Receptor Nomenclature and Drug Classification, proposes a unified nomenclature for Adhesion GPCRs. The new names have ADGR as common dominator followed by a letter and a number to denote each subfamily and subtype, respectively. The new names, with old and alternative......-3, CIRL-3, CL3), ADGRL4 (ELTD1, ETL), and ADGRV1 (VLGR1, GPR98). This review covers all major biologic aspects of Adhesion GPCRs, including evolutionary origins, interaction partners, signaling, expression, physiologic functions, and therapeutic potential....

  8. Structural basis for chemokine recognition and activation of a viral G protein-coupled receptor

    Energy Technology Data Exchange (ETDEWEB)

    Burg, John S.; Ingram, Jessica R.; Venkatakrishnan, A.J.; Jude, Kevin M.; Dukkipati, Abhiram; Feinberg, Evan N.; Angelini, Alessandro; Waghray, Deepa; Dror, Ron O.; Ploegh, Hidde L.; Garcia, K. Christopher (Stanford); (Stanford-MED); (Whitehead); (MIT)

    2015-03-05

    Chemokines are small proteins that function as immune modulators through activation of chemokine G protein-coupled receptors (GPCRs). Several viruses also encode chemokines and chemokine receptors to subvert the host immune response. How protein ligands activate GPCRs remains unknown. We report the crystal structure at 2.9 angstrom resolution of the human cytomegalovirus GPCR US28 in complex with the chemokine domain of human CX3CL1 (fractalkine). The globular body of CX3CL1 is perched on top of the US28 extracellular vestibule, whereas its amino terminus projects into the central core of US28. The transmembrane helices of US28 adopt an active-state-like conformation. Atomic-level simulations suggest that the agonist-independent activity of US28 may be due to an amino acid network evolved in the viral GPCR to destabilize the receptor’s inactive state.

  9. High content screening for G protein-coupled receptors using cell-based protein translocation assays

    DEFF Research Database (Denmark)

    Grånäs, Charlotta; Lundholt, Betina Kerstin; Heydorn, Arne

    2005-01-01

    G protein-coupled receptors (GPCRs) have been one of the most productive classes of drug targets for several decades, and new technologies for GPCR-based discovery promise to keep this field active for years to come. While molecular screens for GPCR receptor agonist- and antagonist-based drugs...... will continue to be valuable discovery tools, the most exciting developments in the field involve cell-based assays for GPCR function. Some cell-based discovery strategies, such as the use of beta-arrestin as a surrogate marker for GPCR function, have already been reduced to practice, and have been used...... as valuable discovery tools for several years. The application of high content cell-based screening to GPCR discovery has opened up additional possibilities, such as direct tracking of GPCRs, G proteins and other signaling pathway components using intracellular translocation assays. These assays provide...

  10. G-protein-Coupled Receptors and Their (Bio Chemical Significance Win 2012 Nobel Prize in Chemistry

    Directory of Open Access Journals (Sweden)

    Hsi-Hsien Lin

    2013-06-01

    Full Text Available G-protein-coupled receptors (GPCRs are seven transmembrane cell surface proteins specialized in cellular communication. These receptors represent a major gateway through which cells convert external cues into intracellular signals and respond with appropriate actions. While the effects of hormones, neurotransmitters, and drugs on cells, tissues, organs, and even whole organisms are well described, the molecular identity of the direct targets and the diverse signaling mechanisms of these biological ligands have been slow and hard to define. The Nobel Prize in Chemistry for the year 2012 acknowledges the importance of GPCRs in these processes, especially for the contribution of Profs Robert J. Lefkowitz and Brian K. Kobilka to the studies of GPCRs. In this brief review, the seminal works accomplished by the two GPCR pioneers are summarized and the (bio chemical significance of GPCRs in health and disease is discussed.

  11. Structural predictions of neurobiologically relevant G-protein coupled receptors and intrinsically disordered proteins.

    Science.gov (United States)

    Rossetti, Giulia; Dibenedetto, Domenica; Calandrini, Vania; Giorgetti, Alejandro; Carloni, Paolo

    2015-09-15

    G protein coupled receptors (GPCRs) and intrinsic disordered proteins (IDPs) are key players for neuronal function and dysfunction. Unfortunately, their structural characterization is lacking in most cases. From one hand, no experimental structure has been determined for the two largest GPCRs subfamilies, both key proteins in neuronal pathways. These are the odorant (450 members out of 900 human GPCRs) and the bitter taste receptors (25 members) subfamilies. On the other hand, also IDPs structural characterization is highly non-trivial. They exist as dynamic, highly flexible structural ensembles that undergo conformational conversions on a wide range of timescales, spanning from picoseconds to milliseconds. Computational methods may be of great help to characterize these neuronal proteins. Here we review recent progress from our lab and other groups to develop and apply in silico methods for structural predictions of these highly relevant, fascinating and challenging systems. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. The Effect of Histamine on the Rat Oestrous Cycle | Anuka | West ...

    African Journals Online (AJOL)

    Intracerebroventricular (icv) administration of histamine (80-120mg) to adult Wistar rats was found to induce irregular cycles and, at times, persistent oestrous cycle when administered at different stages of the cycle. Cimetidine (50 mg/kg), a H2-receptor antagonist, administered intraperitoneally (ip) produced a transient ...

  13. Determination of histamine in Iranian cheese using enzyme-linked ...

    African Journals Online (AJOL)

    Histamine is a simple chemical substance created during processing of the amine acid histidine. Histamine is also an agent in inflammation and the increased presence of histamine causes allergic reaction. Histamine may play a role in the increased prevalence of food intolerances. The objective of this study was to ...

  14. High-resolution crystal structure of an engineered human beta2-adrenergic G protein-coupled receptor

    DEFF Research Database (Denmark)

    Cherezov, Vadim; Rosenbaum, Daniel M; Hanson, Michael A

    2007-01-01

    Heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors constitute the largest family of eukaryotic signal transduction proteins that communicate across the membrane. We report the crystal structure of a human beta2-adrenergic receptor-T4 lysozyme fusion protein bound...... to the partial inverse agonist carazolol at 2.4 angstrom resolution. The structure provides a high-resolution view of a human G protein-coupled receptor bound to a diffusible ligand. Ligand-binding site accessibility is enabled by the second extracellular loop, which is held out of the binding cavity by a pair...

  15. Mechanisms of G Protein-Coupled Estrogen Receptor-Mediated Spinal Nociception

    DEFF Research Database (Denmark)

    Deliu, Elena; Brailoiu, G. Cristina; Arterburn, Jeffrey B.

    2012-01-01

    Human and animal studies suggest that estrogens are involved in the processing of nociceptive sensory information and analgesic responses in the central nervous system. Rapid pronociceptive estrogenic effects have been reported, some of which likely involve G protein-coupled estrogen receptor (GPER...... increase, ROS accumulation, and neuronal membrane depolarization. PerspectiveOur results suggest that GPER modulates pain processing in spinal sensory neurons via cytosolic calcium increase and ROS accumulation. These findings extend the current knowledge on GPER involvement in physiology and disease...

  16. Lactate Receptor Sites Link Neurotransmission, Neurovascular Coupling, and Brain Energy Metabolism

    DEFF Research Database (Denmark)

    Lauritzen, Knut H; Morland, Cecilie; Puchades, Maja

    2013-01-01

    by physiological concentrations of lactate and by the specific GPR81 agonist 3,5-dihydroxybenzoate to reduce cAMP. Cerebral GPR81 is concentrated on the synaptic membranes of excitatory synapses, with a postsynaptic predominance. GPR81 is also enriched at the blood-brain-barrier: the GPR81 densities at endothelial......The G-protein-coupled lactate receptor, GPR81 (HCA1), is known to promote lipid storage in adipocytes by downregulating cAMP levels. Here, we show that GPR81 is also present in the mammalian brain, including regions of the cerebral neocortex and hippocampus, where it can be activated...

  17. Histamine release and fibrinogen adsorption mediate acute inflammatory responses to biomaterial implants in humans

    Directory of Open Access Journals (Sweden)

    Eaton John W

    2007-07-01

    Full Text Available Abstract Background Medical implants often fail as a result of so-called foreign body reactions during which inflammatory cells are recruited to implant surfaces. Despite the clinical importance of this phenomenon, the mechanisms involved in these reactions to biomedical implants in humans are not well understood. The results from animal studies suggest that both fibrinogen adsorption to the implant surface and histamine release by local mast cells are involved in biomaterial-mediated acute inflammatory responses. The purpose of this study was to test this hypothesis in humans. Methods Thirteen male medical student volunteers (Caucasian, 21–30 years of age were employed for this study. To assess the importance of fibrinogen adsorption, six volunteers were implanted with polyethylene teraphthalate disks pre-coated with their own (fibrinogen-containing plasma or (fibrinogen-free serum. To evaluate the importance of histamine, seven volunteers were implanted with uncoated disks with or without prior oral administration of histamine receptor antagonists. The acute inflammatory response was estimated 24 hours later by measuring the activities of implant-associated phagocyte-specific enzymes. Results Plasma coated implants accumulated significantly more phagocytes than did serum coated implants and the recruited cells were predominantly macrophage/monocytes. Administration of both H1 and H2 histamine receptor antagonists greatly reduced the recruitment of macrophages/monocytes and neutrophils on implant surfaces. Conclusion In humans – as in rodents – biomaterial-mediated inflammatory responses involve at least two crucial events: histamine-mediated phagocyte recruitment and phagocyte accumulation on implant surfaces engendered by spontaneously adsorbed host fibrinogen. Based on these results, we conclude that reducing fibrinogen:surface interactions should enhance biocompatibility and that administration of histamine receptor antagonists prior

  18. Histamine release and fibrinogen adsorption mediate acute inflammatory responses to biomaterial implants in humans

    Science.gov (United States)

    Zdolsek, Johann; Eaton, John W; Tang, Liping

    2007-01-01

    Background Medical implants often fail as a result of so-called foreign body reactions during which inflammatory cells are recruited to implant surfaces. Despite the clinical importance of this phenomenon, the mechanisms involved in these reactions to biomedical implants in humans are not well understood. The results from animal studies suggest that both fibrinogen adsorption to the implant surface and histamine release by local mast cells are involved in biomaterial-mediated acute inflammatory responses. The purpose of this study was to test this hypothesis in humans. Methods Thirteen male medical student volunteers (Caucasian, 21–30 years of age) were employed for this study. To assess the importance of fibrinogen adsorption, six volunteers were implanted with polyethylene teraphthalate disks pre-coated with their own (fibrinogen-containing) plasma or (fibrinogen-free) serum. To evaluate the importance of histamine, seven volunteers were implanted with uncoated disks with or without prior oral administration of histamine receptor antagonists. The acute inflammatory response was estimated 24 hours later by measuring the activities of implant-associated phagocyte-specific enzymes. Results Plasma coated implants accumulated significantly more phagocytes than did serum coated implants and the recruited cells were predominantly macrophage/monocytes. Administration of both H1 and H2 histamine receptor antagonists greatly reduced the recruitment of macrophages/monocytes and neutrophils on implant surfaces. Conclusion In humans – as in rodents – biomaterial-mediated inflammatory responses involve at least two crucial events: histamine-mediated phagocyte recruitment and phagocyte accumulation on implant surfaces engendered by spontaneously adsorbed host fibrinogen. Based on these results, we conclude that reducing fibrinogen:surface interactions should enhance biocompatibility and that administration of histamine receptor antagonists prior to, and shortly after

  19. Drug Discovery Targeting Serotonin G Protein-Coupled Receptors in the Treatment of Neuropsychiatric Disorders

    Science.gov (United States)

    Felsing, Daniel E.

    Clinical data show that activation of 5-HT2C G protein-coupled receptors (GPCRs) can treat obesity (lorcaserin/BelviqRTM) and psychotic disorders (aripiprazole/Abilify.), including schizophrenia. 5-HT2C GPCRs are members of the 5-HT2 sub-family of 5-HT GPCRs, which include 5-HT2A, 5-HT2B, and 5-HT 2C GPCRs. 5-HT2C is structurally similar to 5-HT2A and 5-HT2B GPCRs, but activation of 5-HT2A and/or 5-HT 2B causes deleterious effects, including hallucinations and cardiac valvulopathy. Thus, there is a challenge to develop drugs that selectively activate only 5-HT2C. Prolonged activation of GPCRs by agonists reduces their function via a regulatory process called desensitization. This has clinical relevance, as 45% of drugs approved by the FDA target GPCRs, and agonist drugs (e.g., morphine) typically lose efficacy over time due to desensitization, which invites tolerance. Agonists that cause less desensitization may show extended clinical efficacy as well as a more acceptable clinical dose range. We hypothesized that structurally distinct agonists of the 5-HT2C receptor may cause varying degrees of desensitization by stabilizing unique 5-HT2C receptor conformations. Discovery of 5-HT2C agonists that exhibit minimal desensitization is therapeutically relevant for the pharmacotherapeutic treatment of chronic diseases such as obesity and psychotic disorders. The 5-HT7 receptor has recently been discovered as a druggable target, and selective activation of the 5-HT7 receptor has been shown to alleviate locomotor deficits in mouse models of Rett Syndrome. Additionally, buspirone has been shown to display therapeutically relevant affinity at 5-HT 1A and is currently in phase II clinical trials to treat stereotypy in children with autism. The 5-PAT chemical scaffold shows high affinity towards the 5-HT7 and 5-HT1A receptors. Modulations around the 5-phenyl moiety were able to improve selectivity in binding towards the 5-HT 7 receptor, whereas modulations of the alkyl chains

  20. Macrocyclic chelator-coupled gastrin-based radiopharmaceuticals for targeting of gastrin receptor-expressing tumours

    Energy Technology Data Exchange (ETDEWEB)

    Good, Stephan; Wang, Xuejuan; Maecke, Helmut R. [University Hospital Basel, Division of Radiological Chemistry, Basel (Switzerland); Walter, Martin A.; Mueller-Brand, Jan [University Hospital, Institute of Nuclear Medicine, Basel (Switzerland); Waser, Beatrice; Reubi, Jean-Claude [University of Berne, Department of Pathology, Bern (Switzerland); Behe, Martin P. [Philipps-University of Marburg, Department of Nuclear Medicine, Marburg (Germany)

    2008-10-15

    Diethylenetriamine-pentaacetic acid (DTPA)-coupled minigastrins are unsuitable for therapeutic application with the available {beta}-emitting radiometals due to low complex stability. Low tumour-to-kidney ratio of the known radiopharmaceuticals is further limiting their potency. We used macrocyclic chelators for coupling to increase complex stability, modified the peptide sequence to enhance radiolytic stability and studied tumour-to-kidney ratio and metabolic stability using {sup 111}In-labelled derivatives. Gastrin derivatives with decreasing numbers of glutamic acids were synthesised using {sup 111}In as surrogate for therapeutic radiometals for in vitro and in vivo studies. Gastrin receptor affinities of the {sup nat}In-metallated compounds were determined by receptor autoradiography using {sup 125}I-CCK as radioligand. Internalisation was evaluated in AR4-2J cells. Enzymatic stability was determined by incubating the {sup 111}In-labelled peptides in human serum. Biodistribution was performed in AR4-2J-bearing Lewis rats. IC{sub 50} values of the {sup nat}In-metallated gastrin derivatives vary between 1.2 and 4.8 nmol/L for all methionine-containing derivatives. Replacement of methionine by norleucine, isoleucine, methionine-sulfoxide and methionine-sulfone resulted in significant decrease of receptor affinity (IC{sub 50} between 9.9 and 1,195 nmol/L). All cholecystokinin receptor affinities were >100 nmol/L. All {sup 111}In-labelled radiopeptides showed receptor-specific internalisation. Serum mean-life times varied between 2.0 and 72.6 h, positively correlating with the number of Glu residues. All {sup 111}In-labelled macrocyclic chelator conjugates showed higher tumour-to-kidney ratios after 24 h (0.37-0.99) compared to {sup 111}In-DTPA-minigastrin 0(0.05). Tumour wash out between 4 and 24 h was low. Imaging studies confirmed receptor-specific blocking of the tumour uptake. Reducing the number of glutamates increased tumour-to-kidney ratio but resulted in

  1. A constitutively active G-protein-coupled receptor causes mating self-compatibility in the mushroom Coprinus.

    Science.gov (United States)

    Olesnicky, N S; Brown, A J; Dowell, S J; Casselton, L A

    1999-01-01

    In the mushroom Coprinus cinereus, the multiallelic B mating type genes are predicted to encode a large family of seven-transmembrane domain receptors and CaaX-modified pheromones. We have shown that a single amino acid change Q229P in transmembrane domain VI of one receptor confers a self-compatible mating phenotype. Using a heterologous yeast assay, we have demonstrated that this C.cinereus pheromone receptor is a G-protein-coupled receptor and that the Q229P mutation is constitutively activating. A C.cinereus pheromone precursor was processed to an active species specifically in yeast MATa cells and activated the co-expressed wild-type receptor. Yeast cells expressing the wild-type receptor were used to test the activity of synthetic peptides, enabling us to predict the structure of the mature C.cinereus pheromone and to show that the Q229P mutation does not compromise normal receptor function. PMID:10329622

  2. Degradation of Histamine by Lactobacillus plantarum Isolated from Miso Products.

    Science.gov (United States)

    Kung, Hsien-Feng; Lee, Yi-Chen; Huang, Ya-Ling; Huang, Yu-Ru; Su, Yi-Cheng; Tsai, Yung-Hsiang

    2017-10-01

    Histamine is a toxic chemical and is the causative agent of food poisoning. This foodborne toxin may be degraded by the oxidative deamination activity of certain microorganisms. In this study, we isolated four histamine-degrading Lactobacillus plantarum bacteria from miso products. Among them, L. plantarum D-103 exhibited 100% degradation of histamine in de Man Rogosa Sharpe (MRS) broth containing 50 ppm of histamine after 24 h of incubation at 30°C. The optimal growth, histamine oxidase, and histamine-degrading activity of L. plantarum D-103 were observed in histamine MRS broth at pH 7.0, 3% NaCl, and 30°C. It also exhibited tolerance to broad ranges of pH (4 to 10) and salt concentrations (0 to 12%) in histamine MRS broth. Therefore, the histamine-degrading L. plantarum D-103 might be used as an additive culture to prevent histamine accumulation in miso products during fermentation.

  3. Model-Based Discovery of Synthetic Agonists for the Zn2+-Sensing G-Protein-Coupled Receptor 39 (GPR39) Reveals Novel Biological Functions

    DEFF Research Database (Denmark)

    Frimurer, Thomas M.; Mende, Franziska; Graae, Anne-Sofie

    2017-01-01

    The G-protein coupled receptor 39 (GPR39) is a G protein-coupled receptor activated by Zn2. We used a homol. model-based approach to identify small-mol. pharmacol. tool compds. for the receptor. The method focused on a putative binding site in GPR39 for synthetic ligands and knowledge of ligand b...

  4. Mitochondrial signaling for histamine releases in laser-irradiated RBL-2H3 mast cells.

    Science.gov (United States)

    Wu, Zu-Hui; Zhou, Yu; Chen, Ji-Yao; Zhou, Lu-Wei

    2010-08-01

    The low power laser irradiation (LPLI) can promote the wound healing, but the mechanism is still not fully understood. We have found in our previous work that the LPLI induces mast cells to release the histamine and thus suggested that the increased histamine release is probably one of the causes for promoting the wound healing since mast cells have been found to play positive roles in the process of wound healing. This study aims to explore the mechanism of histamine release in RBL-2H3 mast cells under laser irradiations. The wavelength effect of laser irradiations, the permeability function of mitochondrial membrane, the Bcl-2 effect, the cytosolic alkalinization and the increment of intracellular Ca(2+) ([Ca(2+)](i)), on histamine release in RBL-2H3 cells were studied, respectively, with the corresponding fluorescence probes. The action bands of laser irradiations were consistent with the absorption bands of cytochrome c oxidase, suggesting that cytochrome c oxidase is the photoacceptor. After laser irradiation, (1) the cytochrome c releases from mitochondrial to cytosol reflecting an increased permeability of mitochondrial membrane, (2) the cytosolic alkalinization appears, (3) [Ca(2+)](i) increases, and (4) finally the enhancement of histamine release occurs. When Bcl-2 was used to inhibit the permeability of mitochondrial membrane these cellular signaling from (1) to (4) were all suppressed obviously. As a photoacceptor, cytochrome c oxidase absorbs incident photons and initiates the mitochondrial signaling. When the signals are transferred from the mitochondrial to the cytosol, the cytosolic alkalinization appears leading to the opening of a Ca(2+) channel on the membrane, the transient receptor potential vanilloid (TRPV), and an increment of [Ca(2+)](i). The increased [Ca(2+)](i) consequently mediates an enhanced histamine release. Such a responding chain is a suggested mechanism to understand the histamine release in RBL-2H3 cells under laser irradiations

  5. Simple and rapid determination of histamine in food using a new histamine dehydrogenase from Rhizobium sp.

    Science.gov (United States)

    Sato, Tsuneo; Horiuchi, Tatsuo; Nishimura, Ikuko

    2005-11-15

    A colorimetric enzyme assay for the quantitative analysis of histamine in food has been developed using a new histamine dehydrogenase (HDH) from Rhizobium sp. The HDH specifically catalyzes the oxidation of histamine but not other biogenic amines such as putrescine and cadaverine. The principle of our photometric assay is as follows. The HDH catalyzes the oxidative deamination of histamine in the presence of 1-methoxy PMS (electron carrier), which converts WST-8 (tetrazolium salt) to a formazan. This product is measured in the visible range at 460 nm. The correlation between the histamine level and absorbance was acceptable, ranging from 0 to 96 microM with histamine standard solutions, corresponding to 0 to 30 microM of the reaction solution (r = 1.000, CV = 1.0% or less). Assays of canned tuna (in oil and soup) and raw tuna with 45-675 micromol/kg histamine added showed good recoveries of 96-113, 98-108, and 100-106%. The histamine contents of a commercial canned tuna and fish meal containing histamine at high concentrations were determined using the new method and other reference methods (HPLC method, Association of Official Analytical Chemists official method, and two commercial enzyme immunoassay test kits). This simple and rapid enzymatic method is as reliable as the conventional methods.

  6. A mixture of anatase and rutile TiO2 nanoparticles induces histamine secretion in mast cells

    Directory of Open Access Journals (Sweden)

    Chen Eric Y

    2012-01-01

    Full Text Available Abstract Background Histamine released from mast cells, through complex interactions involving the binding of IgE to FcεRI receptors and the subsequent intracellular Ca2+ signaling, can mediate many allergic/inflammatory responses. The possibility of titanium dioxide nanoparticles (TiO2 NPs, a nanomaterial pervasively used in nanotechnology and pharmaceutical industries, to directly induce histamine secretion without prior allergen sensitization has remained uncertain. Results TiO2 NP exposure increased both histamine secretion and cytosolic Ca2+ concentration ([Ca2+]C in a dose dependent manner in rat RBL-2H3 mast cells. The increase in intracellular Ca2+ levels resulted primarily from an extracellular Ca2+ influx via membrane L-type Ca2+ channels. Unspecific Ca2+ entry via TiO2 NP-instigated membrane disruption was demonstrated with the intracellular leakage of a fluorescent calcein dye. Oxidative stress induced by TiO2 NPs also contributed to cytosolic Ca2+ signaling. The PLC-IP3-IP3 receptor pathways and endoplasmic reticulum (ER were responsible for the sustained elevation of [Ca2+]C and histamine secretion. Conclusion Our data suggests that systemic circulation of NPs may prompt histamine release at different locales causing abnormal inflammatory diseases. This study provides a novel mechanistic link between environmental TiO2 NP exposure and allergen-independent histamine release that can exacerbate manifestations of multiple allergic responses.

  7. G-protein-coupled receptor signaling and neural tube closure defects.

    Science.gov (United States)

    Shimada, Issei S; Mukhopadhyay, Saikat

    2017-01-30

    Disruption of the normal mechanisms that mediate neural tube closure can result in neural tube defects (NTDs) with devastating consequences in affected patients. With the advent of next-generation sequencing, we are increasingly detecting mutations in multiple genes in NTD cases. However, our ability to determine which of these genes contribute to the malformation is limited by our understanding of the pathways controlling neural tube closure. G-protein-coupled receptors (GPCRs) comprise the largest family of transmembrane receptors in humans and have been historically favored as drug targets. Recent studies implicate several GPCRs and downstream signaling pathways in neural tube development and closure. In this review, we will discuss our current understanding of GPCR signaling pathways in pathogenesis of NTDs. Notable examples include the orphan primary cilia-localized GPCR, Gpr161 that regulates the basal suppression machinery of sonic hedgehog pathway by means of activation of cAMP-protein kinase A signaling in the neural tube, and protease-activated receptors that are activated by a local network of membrane-tethered proteases during neural tube closure involving the surface ectoderm. Understanding the role of these GPCR-regulated pathways in neural tube development and closure is essential toward identification of underlying genetic causes to prevent NTDs. Birth Defects Research 109:129-139, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. The G protein-coupled receptor heterodimer network (GPCR-HetNet) and its hub components.

    Science.gov (United States)

    Borroto-Escuela, Dasiel O; Brito, Ismel; Romero-Fernandez, Wilber; Di Palma, Michael; Oflijan, Julia; Skieterska, Kamila; Duchou, Jolien; Van Craenenbroeck, Kathleen; Suárez-Boomgaard, Diana; Rivera, Alicia; Guidolin, Diego; Agnati, Luigi F; Fuxe, Kjell

    2014-05-14

    G protein-coupled receptors (GPCRs) oligomerization has emerged as a vital characteristic of receptor structure. Substantial experimental evidence supports the existence of GPCR-GPCR interactions in a coordinated and cooperative manner. However, despite the current development of experimental techniques for large-scale detection of GPCR heteromers, in order to understand their connectivity it is necessary to develop novel tools to study the global heteroreceptor networks. To provide insight into the overall topology of the GPCR heteromers and identify key players, a collective interaction network was constructed. Experimental interaction data for each of the individual human GPCR protomers was obtained manually from the STRING and SCOPUS databases. The interaction data were used to build and analyze the network using Cytoscape software. The network was treated as undirected throughout the study. It is comprised of 156 nodes, 260 edges and has a scale-free topology. Connectivity analysis reveals a significant dominance of intrafamily versus interfamily connections. Most of the receptors within the network are linked to each other by a small number of edges. DRD2, OPRM, ADRB2, AA2AR, AA1R, OPRK, OPRD and GHSR are identified as hubs. In a network representation 10 modules/clusters also appear as a highly interconnected group of nodes. Information on this GPCR network can improve our understanding of molecular integration. GPCR-HetNet has been implemented in Java and is freely available at http://www.iiia.csic.es/~ismel/GPCR-Nets/index.html.

  9. G protein-coupled receptor modulation with pepducins: moving closer to the clinic.

    Science.gov (United States)

    Dimond, Patricia; Carlson, Kenneth; Bouvier, Michel; Gerard, Craig; Xu, Lei; Covic, Lidija; Agarwal, Anika; Ernst, Oliver P; Janz, Jay M; Schwartz, Thue W; Gardella, Thomas J; Milligan, Graeme; Kuliopulos, Athan; Sakmar, Thomas P; Hunt, Stephen W

    2011-05-01

    At the 2nd Pepducin Science Symposium held in Cambridge, Massachusetts, on November 4-5, 2010, investigators working in G protein-coupled receptor (GPCR) research convened to discuss progress since last year's inaugural conference. This year's symposium focused on increasing knowledge of the structure and function of this ubiquitous superfamily of membrane receptors and their potential modulation for disease treatment. Presentations also focused on how GPCR mechanisms might be exploited to treat diseases with pepducins, novel synthetic lipopeptide pharmacophores that modulate heptahelical GPCR activity. While the multiple roles of GPCRs in physiological and pathophysiological processes offer significant opportunities for novel drug development, the global nature of their activity challenges drug-specific and validated target identification. This year's conference highlighted advances in understanding of GPCR agonist and antagonist ligand-binding motifs, their ligand-independent functions, structure-activity relationships (SARs), and evolving unique methods to probe GPCR structure and function. Study results summarized at the meeting also provided evidence for evolving views of how signaling mechanisms work through these receptors. © 2011 New York Academy of Sciences.

  10. The orphan G protein-coupled receptor GPR139 is activated by the peptides

    DEFF Research Database (Denmark)

    Jensen, Anne Cathrine Nøhr; Shehata, Mohamed A; Hauser, Alexander S

    2017-01-01

    GPR139 is an orphan G protein-coupled receptor that is expressed primarily in the brain. Not much is known regarding the function of GPR139. Recently we have shown that GPR139 is activated by the amino acids l-tryptophan and l-phenylalanine (EC50 values of 220 μM and 320 μM, respectively), as well...... as di-peptides comprised of aromatic amino acids. This led us to hypothesize that GPR139 may be activated by peptides. Sequence alignment of the binding cavities of all class A GPCRs, revealed that the binding pocket of the melanocortin 4 receptor is similar to that of GPR139. Based on the chemogenomics...... principle "similar targets bind similar ligands", we tested three known endogenous melanocortin 4 receptor agonists; adrenocorticotropic hormone (ACTH) and α- and β-melanocyte stimulating hormone (α-MSH and β-MSH) on CHO-k1 cells stably expressing the human GPR139 in a Fluo-4 Ca(2+)-assay. All three...

  11. G protein-coupled receptor 35: an emerging target in inflammatory and cardiovascular disease

    Directory of Open Access Journals (Sweden)

    Nina eDivorty

    2015-03-01

    Full Text Available G protein coupled receptor 35 (GPR35 is an orphan receptor, discovered in 1998, that has garnered interest as a potential therapeutic target through its association with a range of diseases. However, a lack of pharmacological tools and the absence of convincingly defined endogenous ligands have hampered understanding of function necessary to exploit it therapeutically. Although several endogenous molecules can activate GPR35 none has yet been confirmed as the key endogenous ligand due to reasons that include lack of biological specificity, non-physiologically relevant potency and species ortholog selectivity. Recent advances have identified several highly potent synthetic agonists and antagonists, as well as agonists with equivalent potency at rodent and human orthologs, which will be useful as tool compounds. Homology modelling and mutagenesis studies have provided insight into the mode of ligand binding and possible reasons for the species selectivity of some ligands. Advances have also been made in determining the role of the receptor in disease. In the past, genome-wide association studies have associated GPR35 with diseases such as inflammatory bowel disease, type 2 diabetes and coronary artery disease. More recent functional studies have implicated it in processes as diverse as heart failure and hypoxia, inflammation, pain transduction and synaptic transmission. In this review, we summarise the progress made in understanding the molecular pharmacology, downstream signaling and physiological function of GPR35, and discuss its emerging potential applications as a therapeutic target.

  12. The G Protein-Coupled Receptor Heterodimer Network (GPCR-HetNet and Its Hub Components

    Directory of Open Access Journals (Sweden)

    Dasiel O. Borroto-Escuela

    2014-05-01

    Full Text Available G protein-coupled receptors (GPCRs oligomerization has emerged as a vital characteristic of receptor structure. Substantial experimental evidence supports the existence of GPCR-GPCR interactions in a coordinated and cooperative manner. However, despite the current development of experimental techniques for large-scale detection of GPCR heteromers, in order to understand their connectivity it is necessary to develop novel tools to study the global heteroreceptor networks. To provide insight into the overall topology of the GPCR heteromers and identify key players, a collective interaction network was constructed. Experimental interaction data for each of the individual human GPCR protomers was obtained manually from the STRING and SCOPUS databases. The interaction data were used to build and analyze the network using Cytoscape software. The network was treated as undirected throughout the study. It is comprised of 156 nodes, 260 edges and has a scale-free topology. Connectivity analysis reveals a significant dominance of intrafamily versus interfamily connections. Most of the receptors within the network are linked to each other by a small number of edges. DRD2, OPRM, ADRB2, AA2AR, AA1R, OPRK, OPRD and GHSR are identified as hubs. In a network representation 10 modules/clusters also appear as a highly interconnected group of nodes. Information on this GPCR network can improve our understanding of molecular integration. GPCR-HetNet has been implemented in Java and is freely available at http://www.iiia.csic.es/~ismel/GPCR-Nets/index.html.

  13. Alpha/sub 1/ receptor coupling events initiated by methoxy-substituted tolazoline partial agonists

    Energy Technology Data Exchange (ETDEWEB)

    Wick, P.; Keung, A.; Deth, R.

    1986-03-01

    A series of mono- and dimethyoxy substituted tolazoline derivatives, known to be partial agonists at the alpha/sub 1/ receptor, were compared with the ..cap alpha../sub 1/ selective full agonist phenylephrine (PE) on isolated strips of rabbit aorta Agonist activity was evaluated in contraction, /sup 45/Ca influx, /sup 45/Ca efflux, and /sup 32/P-Phospholipid labelling studies. Maximum contractile responses for the 2-, 3-, and 3, 5- methoxy substituted tolazoline derivatives (10/sup -5/M) were 53.8, 67.6 and 99.7% of the PE (10/sup -5/M) response respectively. These same partial agonists caused a stimulation of /sup 45/Ca influx to the extent of 64, 86, and 95% of the PE response respectively. In /sup 45/Ca efflux studies, (a measure of the intracellular Ca/sup +2/ release) the tolazolines caused: 30%, 63%, and 78% of the PE stimulated level. /sup 32/P-Phosphatidic acid (PA) labelling was measured as an index of PI turnover after ..cap alpha../sub 1/ receptor stimulation. Compared to PE, the 2-, 3-, and 3,5- methoxy substituted tolazoline derivatives caused 22, 46, and 72% PA labelling. The above values are all in reasonable accord with the rank order or agonist activity shown in maximum contractile responses. The results of this investigation suggest that partial agonists stimulate ..cap alpha.. receptor coupling events at a level which is quantitatively comparable to their potencies in causing contraction of arterial smooth muscle.

  14. Tre1, a G protein-coupled receptor, directs transepithelial migration of Drosophila germ cells.

    Directory of Open Access Journals (Sweden)

    Prabhat S Kunwar

    2003-12-01

    Full Text Available In most organisms, germ cells are formed distant from the somatic part of the gonad and thus have to migrate along and through a variety of tissues to reach the gonad. Transepithelial migration through the posterior midgut (PMG is the first active step during Drosophila germ cell migration. Here we report the identification of a novel G protein-coupled receptor (GPCR, Tre1, that is essential for this migration step. Maternal tre1 RNA is localized to germ cells, and tre1 is required cell autonomously in germ cells. In tre1 mutant embryos, most germ cells do not exit the PMG. The few germ cells that do leave the midgut early migrate normally to the gonad, suggesting that this gene is specifically required for transepithelial migration and that mutant germ cells are still able to recognize other guidance cues. Additionally, inhibiting small Rho GTPases in germ cells affects transepithelial migration, suggesting that Tre1 signals through Rho1. We propose that Tre1 acts in a manner similar to chemokine receptors required during transepithelial migration of leukocytes, implying an evolutionarily conserved mechanism of transepithelial migration. Recently, the chemokine receptor CXCR4 was shown to direct migration in vertebrate germ cells. Thus, germ cells may more generally use GPCR signaling to navigate the embryo toward their target.

  15. G Protein-Coupled Receptor 87: a Promising Opportunity for Cancer Drug Discovery.

    Science.gov (United States)

    Zhang, Yanhong; Scoumanne, Ariane; Chen, Xinbin

    2010-01-01

    G protein-coupled receptors (GPRs) constitute one of the largest families of membrane proteins encoded by the human genome. Upon binding to various ligands, these seven-transmembrane receptors play an essential role in many physiological processes, including neurotransmission, immunity, inflammation, regulation of mood and behavior. In view of their important functions, aberrant expression and activity of GPRs have been implicated in a wide spectrum of diseases, including tumorigenesis. GPR87, a cell surface GPR related to the LPA receptor family, is overexpressed in diverse carcinomas and plays an essential role in tumor cell survival. In our recent work, we uncovered that GPR87 expression is regulated by the tumor suppressor p53 and by DNA damage in a p53-dependent manner. Moreover, we found that a lack of GPR87 triggers an increase in p53, concomitant with a decrease in Akt, which results in the sensitization of tumor cells to DNA damage-induced apoptosis and growth suppression. Altogether, we uncovered an essential function for GPR87 in p53-dependent cell survival in response to stress signals. Due to their unique structure, localization and ligand binding ability, GPRs have been extensively used for drug development and are the most common targets of commercial drugs. Although studies are required to determine GPR87 natural ligand(s) and signaling pathways, GPR87 is undoubtedly a very promising novel target for cancer prevention and treatment.

  16. G Protein-Coupled Estrogen Receptor-Selective Ligands Modulate Endometrial Tumor Growth

    Directory of Open Access Journals (Sweden)

    Whitney K. Petrie

    2013-01-01

    Full Text Available Endometrial carcinoma is the most common cancer of the female reproductive tract. GPER/GPR30 is a 7-transmembrane spanning G protein-coupled receptor that has been identified as the third estrogen receptor<