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Sample records for histamine receptors mediate

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

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    Ellen Mueller Fox

    Full Text Available 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.

  2. Histamine H2 Receptor-Mediated Suppression of Intestinal Inflammation by Probiotic Lactobacillus reuteri.

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    Gao, Chunxu; Major, Angela; Rendon, David; Lugo, Monica; Jackson, Vanessa; Shi, Zhongcheng; Mori-Akiyama, Yuko; Versalovic, James

    2015-12-15

    Probiotics and commensal intestinal microbes suppress mammalian cytokine production and intestinal inflammation in various experimental model systems. Limited information exists regarding potential mechanisms of probiotic-mediated immunomodulation in vivo. In this report, we demonstrate that specific probiotic strains of Lactobacillus reuteri suppress intestinal inflammation in a trinitrobenzene sulfonic acid (TNBS)-induced mouse colitis model. Only strains that possess the hdc gene cluster, including the histidine decarboxylase and histidine-histamine antiporter genes, can suppress colitis and mucosal cytokine (interleukin-6 [IL-6] and IL-1β in the colon) gene expression. Suppression of acute colitis in mice was documented by diminished weight loss, colonic injury, serum amyloid A (SAA) protein concentrations, and reduced uptake of [(18)F]fluorodeoxyglucose ([(18)F]FDG) in the colon by positron emission tomography (PET). The ability of probiotic L. reuteri to suppress colitis depends on the presence of a bacterial histidine decarboxylase gene(s) in the intestinal microbiome, consumption of a histidine-containing diet, and signaling via the histamine H2 receptor (H2R). Collectively, luminal conversion of l-histidine to histamine by hdc(+) L. reuteri activates H2R, and H2R signaling results in suppression of acute inflammation within the mouse colon. Probiotics are microorganisms that when administered in adequate amounts confer beneficial effects on the host. Supplementation with probiotic strains was shown to suppress intestinal inflammation in patients with inflammatory bowel disease and in rodent colitis models. However, the mechanisms of probiosis are not clear. Our current studies suggest that supplementation with hdc(+) L. reuteri, which can convert l-histidine to histamine in the gut, resulted in suppression of colonic inflammation. These findings link luminal conversion of dietary components (amino acid metabolism) by gut microbes and probiotic-mediated

  3. Molecular and functional profiling of histamine receptor-mediated calcium ion signals in different cell lines.

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    Meisenberg, Annika; Kaschuba, Dagmar; Balfanz, Sabine; Jordan, Nadine; Baumann, Arnd

    2015-10-01

    Calcium ions (Ca(2+)) play a pivotal role in cellular physiology. Often Ca(2+)-dependent processes are studied in commonly available cell lines. To induce Ca(2+) signals on demand, cells may need to be equipped with additional proteins. A prominent group of membrane proteins evoking Ca(2+) signals are G-protein coupled receptors (GPCRs). These proteins register external signals such as photons, odorants, and neurotransmitters and convey ligand recognition into cellular responses, one of which is Ca(2+) signaling. To avoid receptor cross-talk or cross-activation with introduced proteins, the repertoire of cell-endogenous receptors must be known. Here we examined the presence of histamine receptors in six cell lines frequently used as hosts to study cellular signaling processes. In a concentration-dependent manner, histamine caused a rise in intracellular Ca(2+) in HeLa, HEK 293, and COS-1 cells. The concentration for half-maximal activation (EC50) was in the low micromolar range. In individual cells, transient Ca(2+) signals and Ca(2+) oscillations were uncovered. The results show that (i) HeLa, HEK 293, and COS-1 cells express sufficient amounts of endogenous receptors to study cellular Ca(2+) signaling processes directly and (ii) these cell lines are suitable for calibrating Ca(2+) biosensors in situ based on histamine receptor evoked responses. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. C-terminal of human histamine H1 receptors regulates their agonist-induced clathrin-mediated internalization and G-protein signaling.

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    Hishinuma, Shigeru; Nozawa, Hiroki; Akatsu, Chizuru; Shoji, Masaru

    2016-11-01

    It has been suggested that the agonist-induced internalization of G-protein-coupled receptors from the cell surface into intracellular compartments regulates cellular responsiveness. We previously reported that G q/11 -protein-coupled human histamine H 1 receptors internalized via clathrin-dependent mechanisms upon stimulation with histamine. However, the molecular determinants of H 1 receptors responsible for agonist-induced internalization remain unclear. In this study, we evaluated the roles of the intracellular C-terminal of human histamine H 1 receptors tagged with hemagglutinin (HA) at the N-terminal in histamine-induced internalization in Chinese hamster ovary cells. The histamine-induced internalization was evaluated by the receptor binding assay with [ 3 H]mepyramine and confocal immunofluorescence microscopy with an anti-HA antibody. We found that histamine-induced internalization was inhibited under hypertonic conditions or by pitstop, a clathrin terminal domain inhibitor, but not by filipin or nystatin, disruptors of the caveolar structure and function. The histamine-induced internalization was also inhibited by truncation of a single amino acid, Ser487, located at the end of the intracellular C-terminal of H 1 receptors, but not by its mutation to alanine. In contrast, the receptor-G-protein coupling, which was evaluated by histamine-induced accumulation of [ 3 H]inositol phosphates, was potentiated by truncation of Ser487, but was lost by its mutation to alanine. These results suggest that the intracellular C-terminal of human H 1 receptors, which only comprises 17 amino acids (Cys471-Ser487), plays crucial roles in both clathrin-dependent internalization of H 1 receptors and G-protein signaling, in which truncation of Ser487 and its mutation to alanine are revealed to result in biased signaling toward activation of G-proteins and clathrin-mediated internalization, respectively. © 2016 International Society for Neurochemistry.

  5. Receptor-independent, vacuolar ATPase-mediated cellular uptake of histamine receptor-1 ligands: Possible origin of pharmacological distortions and side effects

    International Nuclear Information System (INIS)

    Morissette, Guillaume; Lodge, Robert; Bouthillier, Johanne; Marceau, Francois

    2008-01-01

    The aims of this study were to investigate whether several histamine receptor agonists and antagonists are subjected to receptor-independent ion trapping into acidic organelles, and whether this sequestration influences their pharmacological or toxicological properties. Vacuolar (V)-ATPase-dependent intracellular sequestration of agonists was recognized as morphological alterations (large fluid-filled vacuoles for betahistine and 1-methylhistamine, granular uptake for fluorescent BODIPY FL histamine) prevented by the specific V-ATPase inhibitor bafilomycin A1 in rabbit vascular smooth muscle cells. Lipophilicity was the major determinant of these cellular effects (order of potency: BODIPY FL histamine > betahistine > 1-methylhistamine > histamine) that occurred at high concentrations. This ranking was dissociable from the potency order for H 1 receptor-mediated contraction of the rabbit aorta, a response uninfluenced by bafilomycin. Antihistamines are inherently more lipophilic and caused vacuolization of a proportion of cells at 5-500 μM. Agonist or antagonist-induced vacuoles were of macroautophagic nature (labeled with GFP-conjugated LC3, Rab7 and CD63; detection of LC3 II). Further, the 2 most lipophilic antihistamines tested, astemizole and terfenadine, were potentiated by V-ATPase blockade in the aortic contractility assay (13- and 3.6-fold more potent, respectively, pA 2 scale), suggesting that V-ATPase-mediated cation trapping sequesters these antagonists from the vicinity of H 1 receptors in the therapeutic concentration range. This potentiation did not apply to less lipophilic antagonists (pyrilamine, diphenhydramine). While some agonists and all tested antagonists of the histamine H 1 receptors induce the V-ATPase-dependent vacuolar and autophagic cytopathology, sequestration affects the pharmacology of only the most lipophilic antagonists, the ones prone to off-target arrhythmogenic side effects

  6. Prenatal Alcohol Exposure Increases Histamine H3 Receptor-Mediated Inhibition of Glutamatergic Neurotransmission in Rat Dentate Gyrus.

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    Varaschin, Rafael K; Allen, Nyika A; Rosenberg, Martina J; Valenzuela, C Fernando; Savage, Daniel D

    2018-02-01

    We have reported that prenatal alcohol exposure (PAE)-induced deficits in dentate gyrus, long-term potentiation (LTP), and memory are ameliorated by the histamine H 3 receptor inverse agonist ABT-239. Curiously, ABT-239 did not enhance LTP or memory in control offspring. Here, we initiated an investigation of how PAE alters histaminergic neurotransmission in the dentate gyrus and other brain regions employing combined radiohistochemical and electrophysiological approaches in vitro to examine histamine H 3 receptor number and function. Long-Evans rat dams voluntarily consumed either a 0% or 5% ethanol solution 4 hours each day throughout gestation. This pattern of drinking, which produces a mean peak maternal serum ethanol concentration of 60.8 ± 5.8 mg/dl, did not affect maternal weight gain, litter size, or offspring birthweight. Radiohistochemical studies in adult offspring revealed that specific [ 3 H]-A349821 binding to histamine H 3 receptors was not different in PAE rats compared to controls. However, H 3 receptor-mediated G i /G o protein-effector coupling, as measured by methimepip-stimulated [ 35 S]-GTPγS binding, was significantly increased in cerebral cortex, cerebellum, and dentate gyrus of PAE rats compared to control. A LIGAND analysis of detailed methimepip concentration-response curves in dentate gyrus indicated that PAE significantly elevates receptor-effector coupling by a lower affinity H 3 receptor population without significantly altering the affinities of H 3 receptor subpopulations. In agreement with the [ 35 S]-GTPγS studies, a similar range of methimepip concentrations also inhibited electrically evoked field excitatory postsynaptic potential responses and increased paired-pulse ratio, a measure of decreased glutamate release, to a significantly greater extent in dentate gyrus slices from PAE rats than in controls. These results suggest that a PAE-induced elevation in H 3 receptor-mediated inhibition of glutamate release from

  7. H4 histamine receptors mediate cell cycle arrest in growth factor-induced murine and human hematopoietic progenitor cells.

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    Anne-France Petit-Bertron

    Full Text Available The most recently characterized H4 histamine receptor (H4R is expressed preferentially in the bone marrow, raising the question of its role during hematopoiesis. Here we show that both murine and human progenitor cell populations express this receptor subtype on transcriptional and protein levels and respond to its agonists by reduced growth factor-induced cell cycle progression that leads to decreased myeloid, erythroid and lymphoid colony formation. H4R activation prevents the induction of cell cycle genes through a cAMP/PKA-dependent pathway that is not associated with apoptosis. It is mediated specifically through H4R signaling since gene silencing or treatment with selective antagonists restores normal cell cycle progression. The arrest of growth factor-induced G1/S transition protects murine and human progenitor cells from the toxicity of the cell cycle-dependent anticancer drug Ara-C in vitro and reduces aplasia in a murine model of chemotherapy. This first evidence for functional H4R expression in hematopoietic progenitors opens new therapeutic perspectives for alleviating hematotoxic side effects of antineoplastic drugs.

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

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    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. Histamine receptors in human detrusor smooth muscle cells: physiological properties and immunohistochemical representation of subtypes.

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    Neuhaus, Jochen; Weimann, Annett; Stolzenburg, Jens-Uwe; Dawood, Waled; Schwalenberg, Thilo; Dorschner, Wolfgang

    2006-06-01

    The potent inflammatory mediator histamine is released from activated mast cells in interstitial cystitis (IC). Here, we report on the histamine receptor subtypes involved in the intracellular calcium response of cultured smooth muscle cells (cSMC). Fura-2 was used to monitor the calcium response in cSMC, cultured from human detrusor biopsies. The distribution of histamine receptor subtypes was addressed by immunocytochemistry in situ and in vitro. Histamine stimulated a maximum of 92% of the cells (n=335), being more effective than carbachol (70%, n=920). HTMT (H1R-agonist), dimaprit (H2R) and MTH (H3R) lead to significant lower numbers of reacting cells (60, 48 and 54%). Histamine receptor immunoreactivity (H1R, H2R, H3R, H4R) was found in situ and in vitro. Histamine-induced calcium increase is mediated by distinct histamine receptors. Thus, pre-therapeutic evaluation of histamine receptor expression in IC patients may help to optimize therapy by using a patient-specific cocktail of subtype-specific histamine receptor antagonists.

  10. Vascular Effects of Histamine

    African Journals Online (AJOL)

    olayemitoyin

    effects of histamine are mediated via H1 and H2 receptors and the actions are modulated by H3 receptor subtype located on presynaptic ... neurotransmittion in the central nervous system and .... Autoinhibition of brain histamine release.

  11. Homologous histamine H1 receptor desensitization results in reduction of H1 receptor agonist efficacy

    NARCIS (Netherlands)

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

    1991-01-01

    Prolonged exposure of the guinea-pig intestinal longitudinal smooth muscle to histamine caused homologous desensitization of the H1 receptor, which led to reduced H1 receptor-mediated production of [3H]inositol phosphates as well as to reduced H1 agonist-induced contractions. [3H]Mepyramine binding

  12. Mast cell-derived histamine mediates cystitis pain.

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    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.

  13. Stimulation of cell proliferation by histamine H2 receptors in dimethylhdrazine-induced adenocarcinomata.

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    Tutton, P J; Barkla, D H

    1978-03-01

    Cell proliferation in dimethylhydrazine-induced colonic carcinomata was stimulated by histamine and by the histamine H2 receptor agonist dimaprit and inhibited by the histamine H2 receptor antagonists Metiamide and Cimetidine but not by the histamine H1 receptor antagonist Mepyramine. In contrast histamine had no effect on colonic crypt cell proliferation in normal or dimethylhydrazine-treated rats.

  14. Inhibition of radiation-induced polyuria by histamine receptor antagonists

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    Donlon, M.A.; Melia, J.A.; Helgeson, E.A.; Wolfe, W.W.

    1986-03-01

    In previous studies the authors have demonstrated that gamma radiation results in polyuria, which is preceded by polydypsia. This suggests that the increased thirst elicited by radiation causes increased urinary volume (UV). Histamine, which is released following radiation exposure, also elicits drinking by nonirradiated rats when administered exogenously. In this study the authors have investigated both the role of water deprivation and the effect of histamine receptor antagonists (HRA) on radiation-induced polyuria. Sprague-Dawley rats were housed individually in metabolic cages. Water was allowed ad libitum except in deprivation experiments where water was removed for 24 hr immediately following radiation. Cimetidine (CIM), an H2 HRA, and dexbromopheniramine (DXB), an H1 HRA, were administered i.p. (16 and 1 mg/kg, respectively) 30 min prior to irradiation (950 rads from a cobalt source). UV was determined at 24-hr intervals for 3 days preceding irradiation and 24 hr postirradiation. UV in DXB treated rats was significantly reduced 24 hr postirradiation (CON = 427 +/- 54%; DXB = 247 +/- 39% of preirradiated CON) compared to postirradiation control values. CIM did not affect postirradiation UV. These data suggest that radiation-induced polyuria is caused by polydypsia which is, in part, mediated by histamine induced by an H1 receptor.

  15. Inhibition of radiation-induced polyuria by histamine receptor antagonists

    International Nuclear Information System (INIS)

    Donlon, M.A.; Melia, J.A.; Helgeson, E.A.; Wolfe, W.W.

    1986-01-01

    In previous studies the authors have demonstrated that gamma radiation results in polyuria, which is preceded by polydypsia. This suggests that the increased thirst elicited by radiation causes increased urinary volume (UV). Histamine, which is released following radiation exposure, also elicits drinking by nonirradiated rats when administered exogenously. In this study the authors have investigated both the role of water deprivation and the effect of histamine receptor antagonists (HRA) on radiation-induced polyuria. Sprague-Dawley rats were housed individually in metabolic cages. Water was allowed ad libitum except in deprivation experiments where water was removed for 24 hr immediately following radiation. Cimetidine (CIM), an H2 HRA, and dexbromopheniramine (DXB), an H1 HRA, were administered i.p. (16 and 1 mg/kg, respectively) 30 min prior to irradiation (950 rads from a cobalt source). UV was determined at 24-hr intervals for 3 days preceding irradiation and 24 hr postirradiation. UV in DXB treated rats was significantly reduced 24 hr postirradiation (CON = 427 +/- 54%; DXB = 247 +/- 39% of preirradiated CON) compared to postirradiation control values. CIM did not affect postirradiation UV. These data suggest that radiation-induced polyuria is caused by polydypsia which is, in part, mediated by histamine induced by an H1 receptor

  16. Albizia lebbeck suppresses histamine signaling by the inhibition of histamine H1 receptor and histidine decarboxylase gene transcriptions.

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    Nurul, Islam Mohammed; Mizuguchi, Hiroyuki; Shahriar, Masum; Venkatesh, Pichairajan; Maeyama, Kazutaka; Mukherjee, Pulok K; Hattori, Masashi; Choudhuri, Mohamed Sahabuddin Kabir; Takeda, Noriaki; Fukui, Hiroyuki

    2011-11-01

    Histamine plays major roles in allergic diseases and its action is mediated mainly by histamine H(1) receptor (H1R). We have demonstrated that histamine signaling-related H1R and histidine decarboxylase (HDC) genes are allergic diseases sensitive genes and their expression level affects severity of the allergic symptoms. Therefore, compounds that suppress histamine signaling should be promising candidates as anti-allergic drugs. Here, we investigated the effect of the extract from the bark of Albizia lebbeck (AL), one of the ingredients of Ayruvedic medicines, on H1R and HDC gene expression using toluene-2,4-diisocyanate (TDI) sensitized allergy model rats and HeLa cells expressing endogenous H1R. Administration of the AL extract significantly decreased the numbers of sneezing and nasal rubbing. Pretreatment with the AL extract suppressed TDI-induced H1R and HDC mRNA elevations as well as [(3)H]mepyramine binding, HDC activity, and histamine content in the nasal mucosa. AL extract also suppressed TDI-induced up-regulation of IL-4, IL-5, and IL-13 mRNA. In HeLa cells, AL extract suppressed phorbol-12-myristate-13-acetate- or histamine-induced up-regulation of H1R mRNA. Our data suggest that AL alleviated nasal symptoms by inhibiting histamine signaling in TDI-sensitized rats through suppression of H1R and HDC gene transcriptions. Suppression of Th2-cytokine signaling by AL also suggests that it could affect the histamine-cytokine network. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Histamine Excites Rat Superior Vestibular Nuclear Neurons via Postsynaptic H1 and H2 Receptors in vitro

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    Qian-Xing Zhuang

    2012-09-01

    Full Text Available The superior vestibular nucleus (SVN, which holds a key position in vestibulo-ocular reflexes and nystagmus, receives direct hypothalamic histaminergic innervations. By using rat brainstem slice preparations and extracellular unitary recordings, we investigated the effect of histamine on SVN neurons and the underlying receptor mechanisms. Bath application of histamine evoked an excitatory response of the SVN neurons, which was not blocked by the low-Ca2+/high-Mg2+ medium, indicating a direct postsynaptic effect of the amine. Selective histamine H1 receptor agonist 2-pyridylethylamine and H2 receptor agonist dimaprit, rather than VUF8430, a selective H4 receptor agonist, mimicked the excitation of histamine on SVN neurons. In addition, selective H1 receptor antagonist mepyramine and H2 receptor antagonist ranitidine, but not JNJ7777120, a selective H4 receptor antagonist, partially blocked the excitatory response of SVN neurons to histamine. Moreover, mepyramine together with ranitidine nearly totally blocked the histamine-induced excitation. Immunostainings further showed that histamine H1 and H2 instead of H4 receptors existed in the SVN. These results demonstrate that histamine excites the SVN neurons via postsynaptic histamine H1 and H2 receptors, and suggest that the central histaminergic innervation from the hypothalamus may actively bias the SVN neuronal activity and subsequently modulate the SVN-mediated vestibular functions and gaze control.

  18. Multiple Targeting Approaches on Histamine H3 Receptor Antagonists

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    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.

  19. Identification of amino acids involved in histamine potentiation of GABA(A receptors

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    Ulrike eThiel

    2015-05-01

    Full Text Available Histamine is a neurotransmitter involved in a number of physiological and neuronal functions. In mammals, such as humans and rodents, the histaminergic neurons found in the tuberomamillary nucleus (TMN project widely throughout the central nervous system (CNS. Histamine acts as positive modulator of GABA(A receptors (GABA(ARs and, in high concentrations (10 mM, as negative modulator of the strychnine-sensitive glycine receptor. However, the exact molecular mechanisms by which histamine acts on GABA(ARs are unknown. In our study, we aimed to identify amino acids potentially involved in the modulatory effect of histamine on GABA(ARs. We expressed GABA(ARs with 12 different point mutations in Xenopus laevis oocytes and characterized the effect of histamine on GABA-induced currents using the two-electrode voltage clamp technique. Our data demonstrate that the amino acid residues ß2(N265 and ß2(M286, which are important for modulation by propofol, are not involved in the action of histamine. However, we found that histamine modulation is dependent on the amino acid residues alpha1(R120, ß2(Y157, ß3(D163, ß3(V175 and ß3(Q185. We showed that the amino acid residues ß2(Y157 and ß3(Q185 mediate the positive modulatory effect of histamine on GABA-induced currents, whereas alpha1(R120 and ß2(D163 form a potential histamine interaction site in GABA(ARs.

  20. 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.

  1. Presynaptic localization of histamine H3-receptors in rat brain

    International Nuclear Information System (INIS)

    Fujimoto, K.; Mizuguchi, H.; Fukui, H.; Wada, H.

    1991-01-01

    The localization of histamine H3-receptors in subcellular fractions from the rat brain was examined in a [3H] (R) alpha-methylhistamine binding assay and compared with those of histamine H1- and adrenaline alpha 1- and alpha 2-receptors. Major [3H](R) alpha-methylhistamine binding sites with increased specific activities ([3H]ligand binding vs. protein amount) were recovered from the P2 fraction by differential centrifugation. Minor [3H](R)alpha-methylhistamine binding sites with increased specific activities were also detected in the P3 fraction. Further subfractionation of the P2 fraction by discontinuous sucrose density gradient centrifugation showed major recoveries of [3H](R)alpha-methylhistamine binding in myelin (MYE) and synaptic plasma membrane (SPM) fractions. A further increase in specific activity was observed in the MYE fraction, but the SPM fraction showed no significant increase in specific activity. Adrenaline alpha 2-receptors, the pre-synaptic autoreceptors, in a [3H] yohimbine binding assay showed distribution patterns similar to histamine H3-receptors. On the other hand, post-synaptic histamine H1- and adrenaline alpha 1-receptors were closely localized and distributed mainly in the SPM fraction with increased specific activity. Only a negligible amount was recovered in the MYE fraction, unlike the histamine H3- and adrenaline alpha 2-receptors

  2. Characteristics of the mouse genomic histamine H1 receptor gene

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Isao; Taniuchi, Ichiro; Kitamura, Daisuke [Kyushu Univ., Fukuoka (Japan)] [and others

    1996-08-15

    We report here the molecular cloning of a mouse histamine H1 receptor gene. The protein deduced from the nucleotide sequence is composed of 488 amino acid residues with characteristic properties of GTP binding protein-coupled receptors. Our results suggest that the mouse histamine H1 receptor gene is a single locus, and no related sequences were detected. Interspecific backcross analysis indicated that the mouse histamine H1 receptor gene (Hrh1) is located in the central region of mouse Chromosome 6 linked to microphthalmia (Mitfmi), ras-related fibrosarcoma oncogene 1 (Raf1), and ret proto-oncogene (Ret) in a region of homology with human chromosome 3p. 12 refs., 3 figs.

  3. 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

  4. 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

  5. Histamine response and local cooling in the human skin: involvement of H1- and H2-receptors.

    Science.gov (United States)

    Grossmann, M; Jamieson, M J; Kirch, W

    1999-08-01

    Histamine may contribute locally to cutaneous blood flow control under normal and pathologic conditions. The objective of this study was to observe the influence of skin temperature on histamine vasodilation, and the roles of H1-and H2-receptors using novel noninvasive methods. Eleven healthy subjects received, double-blind, single doses of the H1-receptor antagonist cetirizine (10 mg), cetirizine (10 mg) plus the H2-receptor antagonist cimetidine (400 mg), or placebo on separate occasions. Histamine was dosed cumulatively by iontophoresis to the forearm skin at 34 degrees C and 14 degrees C. Laser-Doppler flux (LDF) was measured at the same sites using customised probeholder/iontophoretic chambers with Peltier cooling elements. Finger mean arterial pressure (MAP) was measured and cutaneous vascular conductance calculated as LDF/MAP. Histamine vasodilation was reduced in cold skin. Cetirizine shifted the histamine dose-response at both temperatures: statistically significantly at 14 degrees C only. Combined H1- and H2-receptor antagonism shifted the response significantly at both temperatures. H1- and H2-receptors mediate histamine-induced skin vasodilation. The sensitivity of these receptors, particularly the H1- receptor, is attenuated at low skin temperature. Whether the reduced effect in cold skin represents specific receptor or postreceptor desensitization, or nonspecific attenuation of cutaneous vasodilation remains to be elucidated.

  6. Localization and function of histamine H3 receptor in the nasal mucosa

    OpenAIRE

    Suzuki, Shinya; Takeuchi, Kazuhiko; Majima, Yuichi

    2008-01-01

    BACKGROUND: Histamine is an important chemical mediator of allergic rhinitis (AR). Histamine H3 receptors H3R are located on cholinergic and NANC neurons of the myenteric plexus, and activation of H3R regulates gastric acid secretion. However, little is known about the localization and function of H3R in the upper airway. OBJECTIVE: The objective of this study was to examine the localization and possible function of H3R in the nasal mucosa. METHODS: We extracted total RNA from the inferior tu...

  7. Role of histamine receptors in the effects of histamine on the production of reactive oxygen species by whole blood phagocytes

    Czech Academy of Sciences Publication Activity Database

    Vašíček, Ondřej; Lojek, Antonín; Jančinová, V.; Nosál, R.; Číž, Milan

    2014-01-01

    Roč. 100, č. 1 (2014), s. 67-72 ISSN 0024-3205 R&D Projects: GA MŠk(CZ) LD11010 Institutional support: RVO:68081707 Keywords : Histamine * Histamine receptors * Reactive oxygen species Subject RIV: BO - Biophysics Impact factor: 2.702, year: 2014

  8. A new generation of anti-histamines : Histamine H4 receptor antagonists on their way to the clinic

    NARCIS (Netherlands)

    Engelhardt, Harald; Smits, Rogier A; Leurs, Rob; Haaksma, Eric E J; de Esch, Iwan J P

    At the turn of the millennium, the DNA sequence encoding the histamine H4 receptor (H4R) was identified in data from human genome databases. Considering the clinical importance of H1R and H2R ligands, and the clinical trials that are ongoing for H3R ligands, the latest addition to the histamine

  9. Efficacy and safety of histamine-2 receptor antagonists

    NARCIS (Netherlands)

    van der Pol, Rachel; Langendam, Miranda; Benninga, Marc; van Wijk, Michiel; Tabbers, Merit

    2014-01-01

    Histamine-2 receptor antagonists (H2RAs) are frequently used in the treatment of gastroesophageal reflux disease (GERD) in children; however, their efficacy and safety is questionable. To systematically review the literature to assess the efficacy and safety of H2RAs in pediatric GERD. PubMed,

  10. 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...

  11. Mast cell histamine-mediated transient inflammation following exposure to nickel promotes nickel allergy in mice.

    Science.gov (United States)

    Kinbara, Masayuki; Bando, Kanan; Shiraishi, Daisuke; Kuroishi, Toshinobu; Nagai, Yasuhiro; Ohtsu, Hiroshi; Takano-Yamamoto, Teruko; Sugawara, Shunji; Endo, Yasuo

    2016-06-01

    We previously reported that allergic responses to nickel (Ni) were minimal in mice deficient in the histamine-forming enzyme histidine decarboxylase (HDC-KO), suggesting an involvement of histamine in allergic responses to Ni. However, it remains unclear how histamine is involved in the process of Ni allergy. Here, we examined the role of histamine in Ni allergy using a murine model previously established by us. Mice were sensitized to Ni by intraperitoneal injection of a NiCl2 -lipopolysaccharide (LPS) mixture. Ten days later, allergic inflammation was elicited by challenging ear-pinnas intradermally with NiCl2 . Then, ear-swelling was measured. Pyrilamine (histamine H1-receptor antagonist) or cromoglicate (mast cell stabilizer) was intravenously injected 1 h before the sensitization or the challenge. In cell-transfer experiments, spleen cells from Ni-sensitized donor mice were intravenously transferred into non-sensitized recipient mice. In both sensitized and non-sensitized mice, 1 mm or more NiCl2 (injected into ear-pinnas) induced transient non-allergic inflammation (Ni-TI) with accompanying mast cell degranulation. LPS did not affect the magnitude of this Ni-TI. Pyrilamine and cromoglicate reduced either the Ni-TI or the ensuing allergic inflammation when administered before Ni-TI (at either the sensitization or elicitation step), but not if administered when the Ni-TI had subsided. Experiments on HDC-KO and H1-receptor-KO mice, and also cell-transfer experiments using these mice, demonstrated histamine's involvement in both the sensitization and elicitation steps. These results suggest that mast cell histamine-mediated Ni-TI promotes subsequent allergic inflammatory responses to Ni, raising the possibility that control of Ni-TI by drugs may be effective at preventing or reducing Ni allergy. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Human eosinophils - potential pharmacological model applied in human histamine H4 receptor research.

    Science.gov (United States)

    Grosicki, Marek; Kieć-Kononowicz, Katarzyna

    2015-01-01

    Histamine and histamine receptors are well known for their immunomodulatory role in inflammation. In this review we describe the role of histamine and histamine H4 receptor on human eosinophils. In the first part of article we provide short summary of histamine and histamine receptors role in physiology and histamine related therapeutics used in clinics. We briefly describe the human histamine receptor H4 and its ligands, as well as human eosinophils. In the second part of the review we provide detailed description of known histamine effects on eosinophils including: intracellular calcium concentration flux, actin polymerization, cellular shape change, upregulation of adhesion proteins and cellular chemotaxis. We provide proofs that these effects are mainly connected with the activation of histamine H4 receptor. When examining experimental data we discuss the controversial results and limitations of the studies performed on isolated eosinophils. In conclusion we believe that studies on histamine H4 receptor on human eosinophils can provide interesting new biomarkers that can be used in clinical studies of histamine receptors, that in future might result in the development of new strategies in the treatment of chronic inflammatory conditions like asthma or allergy, in which eosinophils are involved.

  13. Histamine delays gastric emptying of solid food in man through histamine, receptors

    International Nuclear Information System (INIS)

    Sridhar, K.; Lange, R.; McCallum, R.W.

    1984-01-01

    The authors have shown that histamine (H) contracts the cat pylorus and duodenum through H/sub 1/ receptor mechanisms. The authors investigated the effect of H infusion on gastric emptying (GE) and the role of H/sub 1/ and H/sub 2/ receptor blockade in healthy volunteers. Radionuclide GE studies were performed using chicken liver labeled in vivo with /sup 99m/Technetium-sulfur colloid as a marker of solid food. Study days were as follows: a baseline GE study (Day 1); H infused continuously IV at a rate of 40 μg/kg/hr during the GE study (Day 2); an IV bolus of 50 mg of diphenhydramine (Day 3), or 300 mg cimetidine (Day 4) given just prior to the continuous infusion of H; a final day when cimetidine was given alone (Day 5). GE was monitored for 2 hours on each day. The results of days 1, 2 and 3 are summarized below (+p<0.05 vs baseline or Day 1). Pretreatment with cimetidine (Day 4) augmented the delay in GE induced by H infusion, while cimetidine without H (Day 5) had no effect on GE. The authors conclude that: 1) H given at a dose which elicits maximal acid secretory response in man significantly delays GE; and 2) H/sub 1/ receptor blockade but not H/sub 2/ blockade prevented this effect. Histamine may play a modulatory role in human gastric emptying through an H/sub 1/ receptor mechanism

  14. Characteristics in Molecular Vibrational Frequency Patterns between Agonists and Antagonists of Histamine Receptors

    Directory of Open Access Journals (Sweden)

    S. June Oh

    2012-06-01

    Full Text Available To learn the differences between the structure-activity relationship and molecular vibration-activity relationship in the ligand-receptor interaction of the histamine receptor, 47 ligands of the histamine receptor were analyzed by structural similarity and molecular vibrational frequency patterns. The radial tree that was produced by clustering analysis of molecular vibrational frequency patterns shows its potential for the functional classification of histamine receptor ligands.

  15. 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.

  16. The role of cortical and hypothalamic histamine-3 receptors in the modulation of central histamine neurotransmission : an in vivo electrophysiology and microdialysis study

    NARCIS (Netherlands)

    Flik, Gunnar; Dremencov, Eliyahu; Cremers, Thomas I. H. F.; Folgering, Joost H. A.; Westerink, Ben H. C.

    2011-01-01

    The current study aimed to investigate the effect of histamine-3 (H3) receptors, expressed in the tuberomammillary nucleus (TMN) of the hypothalamus and in the prefrontal cortex (PFC), on histamine neurotransmission in the rat brain. The firing activity of histamine neurons in the TMN was measured

  17. Histamine H4 receptor in oral lichen planus.

    Science.gov (United States)

    Salem, A; Al-Samadi, A; Stegajev, V; Stark, H; Häyrinen-Immonen, R; Ainola, M; Hietanen, J; Konttinen, Y T

    2015-04-01

    Oral lichen planus (OLP) is an autoimmune disease characterized by a band-like T-cell infiltrate below the apoptotic epithelial cells and degenerated basement membrane. We tested the hypothesis that the high-affinity histamine H4 receptors (H4 Rs) are downregulated in OLP by high histamine concentrations and proinflammatory T-cell cytokines. Immunohistochemistry and immunofluorescence staining, image analysis and quantitative real-time polymerase chain reaction of tissue samples and cytokine-stimulated cultured SCC-25 and primary human oral keratinocytes. H4 R immunoreactivity was weak in OLP and characterized by mast cell (MC) hyperplasia and degranulation. In contrast to controls, H4 R immunostaining and MC counts were negatively correlated in OLP (P = 0.003). H4 R agonist at nanomolar levels led to a rapid internalization of H4 Rs, whereas high histamine concentration and interferon-γ decreased HRH4 -gene transcripts. Healthy oral epithelial cells are equipped with H4 R, which displays a uniform staining pattern in a MC-independent fashion. In contrast, in OLP, increased numbers of activated MCs associate with increasing loss of epithelial H4 R. Cell culture experiments suggest a rapid H4 R stimulation-dependent receptor internalization and a slow cytokine-driven decrease in H4 R synthesis. H4 R may be involved in the maintenance of healthy oral mucosa. In OLP, this maintenance might be impaired by MC degranulation and inflammatory cytokines. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. 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

  19. 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

  20. H1-histamine receptors in the amygdala are involved in emotional memory but do not mediate anxiety-related behaviors in mice submitted to EPM testing.

    Science.gov (United States)

    Serafim, K R; Gianlorenço, A C L; Daher, F P; Mattioli, R

    2012-10-01

    This study investigated the role of amygdala H(1) receptors in state-dependent memory deficits induced by l-histidine (LH). Tests using an elevated plus-maze (EPM) were performed on two consecutive days: Trial 1 (T1) and Trial 2 (T2). Before each trial, mice were intraperitoneally (IP) injected with LH (500mg/kg). Two hours later, they were microinjected with the H(1) receptor antagonist, chlorpheniramine (CPA 0.016, 0.052, or 0.16 nmol/0.1μl), or saline (SAL) into the amygdala and submitted to the EPM. LH-CPA did not affect trial 1 performances in the EPM, which indicated that these drugs did not affect anxiety. Emotional memory, as revealed by a reduction in open arm exploration between both trials, was present in the SAL-SAL groups as well as in the SAL-CPA groups for the lower doses of CPA (0.016 and 0.052nmol). On the contrary, neither the LH-SAL group nor the LH-CPA groups exhibited this decrease in open arm activity between both trials, which reveals that LH impaired emotional memory. While intra-amygdalar CPA did not interact with LH effect, it impaired per se the emotional memory performances at the highest dose (0.16nmol). No significant changes were observed in the number of enclosed arm entries (EAE), an EPM index of general exploratory activity. These results may be attributed to a combined effect in the different nucleus of the amygdala. Taken together, these results suggest that the H(1) receptors in the amygdala are not implicated in anxiety-like behaviors but are involved in emotional states induced by the T1/T2 EPM protocol in mice. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Interaction of active compounds from Aegle marmelos CORREA with histamine-1 receptor

    Science.gov (United States)

    Nugroho, Agung Endro; Agistia, Dany Dwi; Tegar, Maulana; Purnomo, Hari

    2013-01-01

    The aim of this study is to determine the affinity of six active compounds of Aegle Marmelos Correa, they are (E, R)-Marmin, skimmianine, (S)-aegeline, aurapten, zeorin, and dustanin as antihistamines in histamine H1 receptor in comparison to cetirizin, diphenhydramine and chlorpheniramine as ligands comparison. Previously, in the in vitro study marmin obviously antagonized the histamine H1 receptor in a competitive manner. Methods: molecular docking to determine the interaction of ligand binding to its receptor. Lower docking score indicates more stable binding to that protein. Results: Marmin, skimmianine, aegeline, aurapten, zeorin, and dustanin were potential to develop as antihistamine agents, especially as histamine H1 receptor antagonists by interacting with amino acid residues, Asp107, Lys179, Lys191, Asn198, and Trp428 of histamine H1 receptor. Conclusions: Based on molecular docking, Amino acid residues involved in ligand protein interactions were Asp107, Lys179, Lys191, Asn198, and Trp428. PMID:23750086

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

    Directory of Open Access Journals (Sweden)

    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

  3. Characteristics of recombinantly expressed rat and human histamine H3 receptors.

    Science.gov (United States)

    Wulff, Birgitte S; Hastrup, Sven; Rimvall, Karin

    2002-10-18

    Human and rat histamine H(3) receptors were recombinantly expressed and characterized using receptor binding and a functional cAMP assay. Seven of nine agonists had similar affinities and potencies at the rat and human histamine H(3) receptor. S-alpha-methylhistamine had a significantly higher affinity and potency at the human than rat receptor, and for 4-[(1R*,2R*)-2-(5,5-dimethyl-1-hexynyl)cyclopropyl]-1H-imidazole (Perceptin) the preference was the reverse. Only two of six antagonists had similar affinities and potencies at the human and the rat histamine H(3) receptor. Ciproxifan, thioperamide and (1R*,2R*)-trans-2-imidazol-4 ylcyclopropyl) (cyclohexylmethoxy) carboxamide (GT2394) had significantly higher affinities and potencies at the rat than at the human histamine H(3) receptor, while for N-(4-chlorobenzyl)-N-(7-pyrrolodin-1-ylheptyl)guanidine (JB98064) the preference was the reverse. All antagonists also showed potent inverse agonism properties. Iodoproxyfan, Perceptin, proxyfan and GR175737, compounds previously described as histamine H(3) receptor antagonists, acted as full or partial agonists at both the rat and the human histamine H(3) receptor. Copyright 2002 Elsevier Science B.V.

  4. Modulation of Mast Cell Toll-Like Receptor 3 Expression and Cytokines Release by Histamine

    Directory of Open Access Journals (Sweden)

    Guogang Xie

    2018-05-01

    Full Text Available Background/Aims: As a major inflammatory molecule released from mast cell activation, histamine has been reported to regulate TLRs expression and cytokine production in inflammatory cells present in the microenvironment. In this study, we determined the ability of histamine to modulate TLRs expression and cytokine production in mast cells. Methods: HMC-1 and P815 cells were exposed to various concentrations of histamine in the presence or absence of histamine antagonist for 2, 6 or 16 h. The effect of histamine on the expression of TLR3 protein and mRNA was analyzed by flow cytometry、 RT-PCR and immunofluorescent microscopy. Furthermore, we also examined the effect of histamine on the secretion of MCP-1 and IL-13 from mast cells by ELISA. Results: The amplification of TLR3 mRNA and protein expression in mast cells was observed after incubation with histamine, which was accompanied by increasing secretion of IL-13 and MCP-1 via H1 receptor. The signaling pathways of PI3K/ Akt and Erk1/2/MAPK contributed to these induction effects. Conclusion: These results demonstrate that histamine up-regulates the expression of TLR3 and secretion of IL-13 and MCP-1 in mast cells, thus identifying a new mechanism for the histamine inducing allergic response.

  5. 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

  6. Cocaine Disrupts Histamine H3 Receptor Modulation of Dopamine D1 Receptor Signaling: σ1-D1-H3 Receptor Complexes as Key Targets for Reducing Cocaine's Effects

    Science.gov (United States)

    Moreno, Estefanía; Moreno-Delgado, David; Navarro, Gemma; Hoffmann, Hanne M.; Fuentes, Silvia; Rosell-Vilar, Santi; Gasperini, Paola; Rodríguez-Ruiz, Mar; Medrano, Mireia; Mallol, Josefa; Cortés, Antoni; Casadó, Vicent; Lluís, Carme; Ferré, Sergi; Ortiz, Jordi; Canela, Enric

    2014-01-01

    The general effects of cocaine are not well understood at the molecular level. What is known is that the dopamine D1 receptor plays an important role. Here we show that a key mechanism may be cocaine's blockade of the histamine H3 receptor-mediated inhibition of D1 receptor function. This blockade requires the σ1 receptor and occurs upon cocaine binding to σ1-D1-H3 receptor complexes. The cocaine-mediated disruption leaves an uninhibited D1 receptor that activates Gs, freely recruits β-arrestin, increases p-ERK 1/2 levels, and induces cell death when over activated. Using in vitro assays with transfected cells and in ex vivo experiments using both rats acutely treated or self-administered with cocaine along with mice depleted of σ1 receptor, we show that blockade of σ1 receptor by an antagonist restores the protective H3 receptor-mediated brake on D1 receptor signaling and prevents the cell death from elevated D1 receptor signaling. These findings suggest that a combination therapy of σ1R antagonists with H3 receptor agonists could serve to reduce some effects of cocaine. PMID:24599455

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

    International Nuclear Information System (INIS)

    Notcovich, Cintia; Diez, Federico; Tubio, Maria Rosario; Baldi, Alberto; Kazanietz, Marcelo G.; Davio, Carlos; Shayo, Carina

    2010-01-01

    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 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 β2-chimaerin. On the other hand, H1R-induced ERK1/2 activation was inhibited by U73122 but not affected by C3 or β2-chimaerin, suggesting that ERK1/2 activation was dependent on PLC and independent of RhoA or Rac. [ 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.

  8. 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...

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

    Directory of Open Access Journals (Sweden)

    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

  10. Major advances in the development of histamine H4 receptor ligands.

    Science.gov (United States)

    Smits, Rogier A; Leurs, Rob; de Esch, Iwan J P

    2009-08-01

    The search for new and potent histamine H4 receptor ligands is leading to a steadily increasing number of scientific publications and patent applications. Several interesting and structurally diverse compounds have been found, but fierce IP competition for a preferred 2-aminopyrimidine scaffold is becoming apparent. Recent investigations into the role of the histamine H(4)R in (patho)physiology and the use of H4R ligands in in vivo disease models reveal enormous potential in the field of inflammation and allergy, among others. The development of ligands that display activity at two or more histamine receptor (HR) subtypes is another clinical opportunity that is currently being explored. Taken together, the histamine H4R field is gearing up for clinical studies and has the potential to deliver another generation of blockbuster drugs.

  11. Histamine H1 receptors are expressed in mouse and frog semicircular canal sensory epithelia.

    Science.gov (United States)

    Botta, Laura; Tritto, Simona; Perin, Paola; Laforenza, Umberto; Gastaldi, Giulia; Zampini, Valeria; Zucca, Gianpiero; Valli, Stefano; Masetto, Sergio; Valli, Paolo

    2008-03-05

    Histamine-related drugs are commonly used in the treatment of vertigo and related vestibular disorders. Their site and mechanism of action, however, are still poorly understood. To increase our knowledge of the histaminergic system in the vestibular organs, we have investigated the expression of H1 and H3 histamine receptors in the frog and mouse semicircular canal sensory epithelia. Analysis was performed by mRNA reverse transcriptase-PCR, immunoblotting and immunocytochemistry experiments. Our data show that both frog and mouse vestibular epithelia express H1 receptors. Conversely no clear evidence for H3 receptors expression was found.

  12. 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

  13. Waking action of ursodeoxycholic acid (UDCA involves histamine and GABAA receptor block.

    Directory of Open Access Journals (Sweden)

    Yevgenij Yanovsky

    Full Text Available Since ancient times ursodeoxycholic acid (UDCA, a constituent of bile, is used against gallstone formation and cholestasis. A neuroprotective action of UDCA was demonstrated recently in models of Alzheimer's disease and retinal degeneration. The mechanisms of UDCA action in the nervous system are poorly understood. We show now that UDCA promotes wakefulness during the active period of the day, lacking this activity in histamine-deficient mice. In cultured hypothalamic neurons UDCA did not affect firing rate but synchronized the firing, an effect abolished by the GABA(AR antagonist gabazine. In histaminergic neurons recorded in slices UDCA reduced amplitude and duration of spontaneous and evoked IPSCs. In acutely isolated histaminergic neurons UDCA inhibited GABA-evoked currents and sIPSCs starting at 10 µM (IC(50 = 70 µM and did not affect NMDA- and AMPA-receptor mediated currents at 100 µM. Recombinant GABA(A receptors composed of α1, β1-3 and γ2L subunits expressed in HEK293 cells displayed a sensitivity to UDCA similar to that of native GABA(A receptors. The mutation α1V256S, known to reduce the inhibitory action of pregnenolone sulphate, reduced the potency of UDCA. The mutation α1Q241L, which abolishes GABA(AR potentiation by several neurosteroids, had no effect on GABA(AR inhibition by UDCA. In conclusion, UDCA enhances alertness through disinhibition, at least partially of the histaminergic system via GABA(A receptors.

  14. Pharmacology of JB-9315, a new selective histamine H2-receptor antagonist.

    Science.gov (United States)

    Palacios, B; Montero, M J; Sevilla, M A; San Román, L

    1998-02-01

    1. The histamine H2-receptor antagonistic activity and antisecretory and antiulcer effects of JB-9315 were studied in comparison with the standard H2 blocker ranitidine. 2. In vitro, JB-9315 is a competitive antagonist of histamine H2 receptors in the isolated, spontaneously beating guinea-pig right atrium, with a pA2 value of 7.30 relative to a value of 7.36 for ranitidine. JB-9315 was specific for the histamine H2 receptor because, at high concentration, it did not affect histamine- or acetylcholine-induced contractions in guinea-pig isolated ileum or rat isolated duodenum, respectively. 3. JB-9315 dose dependently inhibited histamine-, pentagastrin- or carbachol-stimulated acid secretion and basal secretion in the perfused stomach preparation of the anesthetized rat. In the pylorus-ligated rat after intraperitoneal administration, total acid output over 4 h was inhibited by JB-9315 with an ID50 of 32.8 mg/kg, confirming its H2-receptor antagonist properties. 4. JB-9315 showed antiulcer activity against cold stress plus indomethacin-induced lesions with an ID50 of 6.8 mg/kg. 5. JB-9315, 50 and 100 mg/kg, inhibited macroscopic gastric hemorrhagic lesions induced by ethanol. In contrast, ranitidine (50 mg/kg) failed to reduce these lesions. 6. These results indicate that JB-9315 is a new antiulcer drug that exerts a cytoprotective effect in addition to its gastric antisecretory activity.

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

    Science.gov (United States)

    Jian, Tunyu; Yang, Niuniu; Yang, Yan; Zhu, Chan; Yuan, Xiaolin; Yu, Guang; Wang, Changming; Wang, Zhongli; Shi, Hao; Tang, Min; He, Qian; Lan, Lei; Wu, Guanyi; Tang, Zongxiang

    2016-01-01

    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 Ca(2+) ([Ca(2+)]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 Ca(2+) responses. In addition, immepip-induced [Ca(2+)]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.

  16. 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.

  17. Autonomous control of phosphatidylinositol turnover by histamine and acetylcholine receptors in the NIE-115 neuron-like cell line

    International Nuclear Information System (INIS)

    Large, T.H.; Lambert, M.P.; Cohen, N.M.; Klein, W.L.

    1986-01-01

    Histamine was found to stimulate the turnover of phosphatidylinositol (PI) in cultures of neuron-like NE-115 cells. Turnover was measured by increased production of ( 3 H)inositol phosphates (breakdown) and by accelerated incorporation of 32 P into PI (resynthesis). Data were consistent with hydrolysis of polyphosphoinositides being the initial event in receptor-stimulated PI turnover. This response to histamine desensitized within 10 min. Receptor systems for histamine and acetylcholine were tested for possible interactions: PI turnover in response to dual stimulation was approximately equal to the sum of the individual responses while prior desensitization of the acetylcholine receptor system had no effect on subsequent stimulation of the histamine receptor system. These results are consistent with the hypothesis that components of acetylcholine and histamine receptor systems responsible for PI turnover are autonomously organised and regulated. (author)

  18. 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.

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

    Science.gov (United States)

    Tritto, Simona; Botta, Laura; Zampini, Valeria; Zucca, Gianpiero; Valli, Paolo; Masetto, Sergio

    2009-06-29

    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. 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. 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.

  20. Desipramine inhibits histamine H1 receptor-induced Ca2+ signaling in rat hypothalamic cells.

    Directory of Open Access Journals (Sweden)

    Ji-Ah Kang

    Full Text Available The hypothalamus in the brain is the main center for appetite control and integrates signals from adipose tissue and the gastrointestinal tract. Antidepressants are known to modulate the activities of hypothalamic neurons and affect food intake, but the cellular and molecular mechanisms by which antidepressants modulate hypothalamic function remain unclear. Here we have investigated how hypothalamic neurons respond to treatment with antidepressants, including desipramine and sibutramine. In primary cultured rat hypothalamic cells, desipramine markedly suppressed the elevation of intracellular Ca(2+ evoked by histamine H1 receptor activation. Desipramine also inhibited the histamine-induced Ca(2+ increase and the expression of corticotrophin-releasing hormone in hypothalamic GT1-1 cells. The effect of desipramine was not affected by pretreatment with prazosin or propranolol, excluding catecholamine reuptake activity of desipramine as an underlying mechanism. Sibutramine which is also an antidepressant but decreases food intake, had little effect on the histamine-induced Ca(2+ increase or AMP-activated protein kinase activity. Our results reveal that desipramine and sibutramine have different effects on histamine H1 receptor signaling in hypothalamic cells and suggest that distinct regulation of hypothalamic histamine signaling might underlie the differential regulation of food intake between antidepressants.

  1. Heteroreceptor Complexes Formed by Dopamine D1, Histamine H3, and N-Methyl-D-Aspartate Glutamate Receptors as Targets to Prevent Neuronal Death in Alzheimer's Disease.

    Science.gov (United States)

    Rodríguez-Ruiz, Mar; Moreno, Estefanía; Moreno-Delgado, David; Navarro, Gemma; Mallol, Josefa; Cortés, Antonio; Lluís, Carme; Canela, Enric I; Casadó, Vicent; McCormick, Peter J; Franco, Rafael

    2017-08-01

    Alzheimer's disease (AD) is a neurodegenerative disorder causing progressive memory loss and cognitive dysfunction. Anti-AD strategies targeting cell receptors consider them as isolated units. However, many cell surface receptors cooperate and physically contact each other forming complexes having different biochemical properties than individual receptors. We here report the discovery of dopamine D 1 , histamine H 3 , and N-methyl-D-aspartate (NMDA) glutamate receptor heteromers in heterologous systems and in rodent brain cortex. Heteromers were detected by co-immunoprecipitation and in situ proximity ligation assays (PLA) in the rat cortex where H 3 receptor agonists, via negative cross-talk, and H 3 receptor antagonists, via cross-antagonism, decreased D 1 receptor agonist signaling determined by ERK1/2 or Akt phosphorylation, and counteracted D 1 receptor-mediated excitotoxic cell death. Both D 1 and H 3 receptor antagonists also counteracted NMDA toxicity suggesting a complex interaction between NMDA receptors and D 1 -H 3 receptor heteromer function. Likely due to heteromerization, H 3 receptors act as allosteric regulator for D 1 and NMDA receptors. By bioluminescence resonance energy transfer (BRET), we demonstrated that D 1 or H 3 receptors form heteromers with NR1A/NR2B NMDA receptor subunits. D 1 -H 3 -NMDA receptor complexes were confirmed by BRET combined with fluorescence complementation. The endogenous expression of complexes in mouse cortex was determined by PLA and similar expression was observed in wild-type and APP/PS1 mice. Consistent with allosteric receptor-receptor interactions within the complex, H 3 receptor antagonists reduced NMDA or D 1 receptor-mediated excitotoxic cell death in cortical organotypic cultures. Moreover, H 3 receptor antagonists reverted the toxicity induced by ß 1-42 -amyloid peptide. Thus, histamine H 3 receptors in D 1 -H 3 -NMDA heteroreceptor complexes arise as promising targets to prevent neurodegeneration.

  2. Histamine influences body temperature by acting at H1 and H3 receptors on distinct populations of preoptic neurons.

    Science.gov (United States)

    Lundius, Ebba Gregorsson; Sanchez-Alavez, Manuel; Ghochani, Yasmin; Klaus, Joseph; Tabarean, Iustin V

    2010-03-24

    The preoptic area/anterior hypothalamus, a region that contains neurons that control thermoregulation, is the main locus at which histamine affects body temperature. Here we report that histamine reduced the spontaneous firing rate of GABAergic preoptic neurons by activating H3 subtype histamine receptors. This effect involved a decrease in the level of phosphorylation of the extracellular signal-regulated kinase and was not dependent on synaptic activity. Furthermore, a population of non-GABAergic neurons was depolarized, and their firing rate was enhanced by histamine acting at H1 subtype receptors. In our experiments, activation of the H1R receptors was linked to the PLC pathway and Ca(2+) release from intracellular stores. This depolarization persisted in TTX or when fast synaptic potentials were blocked, indicating that it represents a postsynaptic effect. Single-cell reverse transcription-PCR analysis revealed expression of H3 receptors in a population of GABAergic neurons, while H1 receptors were expressed in non-GABAergic cells. Histamine applied in the median preoptic nucleus induced a robust, long-lasting hyperthermia effect that was mimicked by either H1 or H3 histamine receptor subtype-specific agonists. Our data indicate that histamine modulates the core body temperature by acting at two distinct populations of preoptic neurons that express H1 and H3 receptor subtypes, respectively.

  3. Antagonistic targeting of the histamine H3 receptor decreases caloric intake in higher mammalian species.

    Science.gov (United States)

    Malmlöf, Kjell; Hastrup, Sven; Wulff, Birgitte Schellerup; Hansen, Barbara C; Peschke, Bernd; Jeppesen, Claus Bekker; Hohlweg, Rolf; Rimvall, Karin

    2007-04-15

    The main purpose of this study was to examine the effects of a selective histamine H(3) receptor antagonist, NNC 38-1202, on caloric intake in pigs and in rhesus monkeys. The compound was given intragastrically (5 or 15 mg/kg), to normal pigs (n=7) and subcutaneously (1 or 0.1mg/kg) to obese rhesus monkeys (n=9). The energy intake recorded following administration of vehicle to the same animals served as control for the effect of the compound. In addition, rhesus monkey and pig histamine H(3) receptors were cloned from hypothalamic tissues and expressed in mammalian cell lines. The in vitro antagonist potencies of NNC 38-1202 at the H(3) receptors were determined using a functional GTPgammaS binding assay. Porcine and human H(3) receptors were found to have 93.3% identity at the amino acid level and the close homology between the monkey and human H(3) receptors (98.4% identity) was confirmed. The antagonist potencies of NNC 38-1202 at the porcine, monkey and human histamine H(3) receptors were high as evidenced by K(i)-values being clearly below 20 nM, whereas the K(i)-value on the rat H(3) receptor was significantly higher (56+/-6.0 nM). NNC 38-1202, given to pigs in a dose of 15 mg/kg, produced a significant (p<0.05) reduction (55%) of calorie intake compared with vehicle alone, (132.6+/-10.0 kcal/kgday versus 59.7+/-10.2 kcal/kgday). In rhesus monkeys administration of 0.1 and 1mg/kg decreased (p<0.05) average calorie intakes by 40 and 75%, respectively. In conclusion, the present study demonstrates that antagonistic targeting of the histamine H(3) receptor decreases caloric intake in higher mammalian species.

  4. 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

  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. The Influence of histamine H1-receptor on liver functions in immunized rabbits.

    Science.gov (United States)

    Tripathi, Trivendra; Shahid, Mohammad; Khan, Haris M; Khan, Rahat Ali; Siddiqui, Mashiatullah; Mahdi, Abbas Ali

    2011-10-01

    This study was designed to investigate the functional roles of histamine and histamine H1-receptor agonist and antagonist in the development of liver function impairment in immunized rabbits. The study comprised of six groups containing 18 rabbits each. Group III-VI received histamine (100 μg/kg, s.c.), H1R-agonist (HTMT, 10 μg/kg, s.c.), H1R-antagonist (pheniramine, 10 mg/kg, i.m.), and H1R-antagonist (pheniramine, 10 mg/kg, i.m.) plus histamine (100 μg/kg, s.c.), respectively, b.i.d. for 10 days. Group I (negative control) and group II (positive control) received sterile distilled water intramuscularly b.i.d. for 10 days. Groups II-VI were immunized on day 3 with intravenous injection of SRBC (1 × 10(9) cells/ml). Blood samples were collected on pre-immunization day 0, as well as on days 7-, 14-, 21-, 28-, and 58-post-immunization. Biochemical parameters AST, ALT, alkaline phosphatase and bilirubin [total bilirubin (TB), direct bilirubin (DB), and indirect bilirubin (IB)] were determined. On each experimental day, the mean values of serum enzymes and bilirubin in group I and group II showed no significant changes while in group III, IV, V, and VI, these enzymes and bilirubin levels showed significant changes (p pheniramine, and combination of histamine + pheniramine cause hepatic function impairment in terms of altered serum enzymes and bilirubin levels. The present findings suggest that HTMT causes moderate liver function impairment while others show mild impairment.

  7. JB-9322, a new selective histamine H2-receptor antagonist with potent gastric mucosal protective properties.

    Science.gov (United States)

    Palacios, B; Montero, M J; Sevilla, M A; Román, L S

    1995-05-01

    1. JB-9322 is a selective histamine H2-receptor antagonist with gastric antisecretory activity and mucosal protective properties. 2. The affinity of JB-9322 for the guinea-pig atria histamine H2-receptor was approximately 2 times greater than that of ranitidine. 3. In vivo, the ID50 value for the inhibition of gastric acid secretion in pylorus-ligated rats was 5.28 mg kg-1 intraperitoneally. JB-9322 also dose-dependently inhibited gastric juice volume and pepsin secretion. In gastric lumen-perfused rats, intravenous injection of JB-9322 dose-dependently reduced histamine-, pentagastrin- and carbachol-stimulated gastric acid secretion. 4. JB-9322 showed antiulcer activity against aspirin and indomethacin-induced gastric lesions and was more potent than ranitidine. 5. JB-9322 effectively inhibited macroscopic gastric haemorrhagic lesions induced by ethanol. Intraperitoneal injection was effective in preventing the lesions as well as oral treatment. The oral ID50 value for these lesions was 1.33 mg kg-1. By contrast, ranitidine (50 mg kg-1) failed to reduce these lesions. In addition, the protective effect of JB-9322 was independent of prostaglandin synthesis. 6. These results indicate that JB-9322 is a new antiulcer drug that exerts a potent cytoprotective effect in addition to its gastric antisecretory activity.

  8. A search for presynaptic inhibitory histamine receptors in guinea-pig tissues: Further H3 receptors but no evidence for H4 receptors.

    Science.gov (United States)

    Petri, Doris; Schlicker, Eberhard

    2016-07-01

    The histamine H4 receptor is coupled to Gi/o proteins and expressed on inflammatory cells and lymphoid tissues; it was suggested that this receptor also occurs in the brain or on peripheral neurones. Since many Gi/o protein-coupled receptors, including the H3 receptor, serve as presynaptic inhibitory receptors, we studied whether the sympathetic neurones supplying four peripheral tissues and the cholinergic neurones in the hippocampus from the guinea-pig are equipped with release-modulating H4 and H3 receptors. For this purpose, we preincubated tissue pieces from the aorta, atrium, renal cortex and vas deferens with (3)H-noradrenaline and hippocampal slices with (3)H-choline and determined the electrically evoked tritium overflow. The stimulation-evoked overflow in the five superfused tissues was inhibited by the muscarinic receptor agonist oxotremorine, which served as a positive control, but not affected by the H4 receptor agonist 4-methylhistamine. The H3 receptor agonist R-α-methylhistamine inhibited noradrenaline release in the peripheral tissues without affecting acetylcholine release in the hippocampal slices. Thioperamide shifted the concentration-response curve of histamine in the aorta and the renal cortex to the right, yielding apparent pA2 values of 8.0 and 8.1, respectively, which are close to its affinity at other H3 receptors but higher by one log unit than its pKi at the H4 receptor of the guinea-pig. In conclusion, histamine H4 receptors could not be identified in five experimental models of the guinea-pig that are suited for the detection of presynaptic inhibitory receptors whereas H3 receptors could be shown in the peripheral tissues but not in the hippocampus. This article is part of the Special Issue entitled 'Histamine Receptors'. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Cost-effectiveness of histamine receptor-2 antagonist versus proton pump inhibitor for stress ulcer prophylaxis in critically ill patients*.

    Science.gov (United States)

    MacLaren, Robert; Campbell, Jon

    2014-04-01

    To examine the cost-effectiveness of using histamine receptor-2 antagonist or proton pump inhibitor for stress ulcer prophylaxis. Decision analysis model examining costs and effectiveness of using histamine receptor-2 antagonist or proton pump inhibitor for stress ulcer prophylaxis. Costs were expressed in 2012 U.S. dollars from the perspective of the institution and included drug regimens and the following outcomes: clinically significant stress-related mucosal bleed, ventilator-associated pneumonia, and Clostridium difficile infection. Effectiveness was the mortality risk associated with these outcomes and represented by survival. Costs, occurrence rates, and mortality probabilities were extracted from published data. A simulation model. A mixed adult ICU population. Histamine receptor-2 antagonist or proton pump inhibitor for 9 days of stress ulcer prophylaxis therapy. Output variables were expected costs, expected survival rates, incremental cost, and incremental survival rate. Univariate sensitivity analyses were conducted to determine the drivers of incremental cost and incremental survival. Probabilistic sensitivity analysis was conducted using second-order Monte Carlo simulation. For the base case analysis, the expected cost of providing stress ulcer prophylaxis was $6,707 with histamine receptor-2 antagonist and $7,802 with proton pump inhibitor, resulting in a cost saving of $1,095 with histamine receptor-2 antagonist. The associated mortality probabilities were 3.819% and 3.825%, respectively, resulting in an absolute survival benefit of 0.006% with histamine receptor-2 antagonist. The primary drivers of incremental cost and survival were the assumptions surrounding ventilator-associated pneumonia and bleed. The probabilities that histamine receptor-2 antagonist was less costly and provided favorable survival were 89.4% and 55.7%, respectively. A secondary analysis assuming equal rates of C. difficile infection showed a cost saving of $908 with histamine

  10. The effects of histamine and prostaglandin D2 on rat mast-cell cyclic AMP and mediator release

    International Nuclear Information System (INIS)

    Wescott, S.; Kaliner, M.

    1981-01-01

    The possibility that histamine may play a functional role in modulating mast-cell secretion, as has been suggested for basophil degranulation, has both physiologic and pharmacologic implications. Therefore the capacity of histamine to influence rat peritoneal mast-cell (RPMC) cyclic AMP levels and reversed anaphylatic degranulation as reflected in the release of 3H-serotonin (5-HT) was examined. To ascertain that RPMC were functionally responsive to exogenous hormonal stimulation, assessment of prostaglandin (PG) D2 effects on cyclic AMP and 5-HT release were determined in parallel. Although PGD2 (100 microM) increased cyclic AMP and inhibited 5-HT release in the presence of 50 microM aminophylline, histamine (up to 1000 microM) was ineffective was ineffective in both. However, 1000 microM histamine in the presence of 500 microM aminophylline was capable of transiently increasing RPMC cyclic AMP (for 15 to 30 sec) and under these conditions of suppressing 5-HT release. The receptor subtype involved in the suppressive actions of histamine appeared to be of the H-1 type as reflected in the capacity of specific H-1 agonists to reproduce the inhibition of 5-HT release, whereas neither H-2 agonists nor H-2 antagonists had any influence. Thus, under conditions in which phosphodiesterase enzymatic action is impaired, histamine in extremely high concentrations is able to modulate mast-cell secretion. However, it seems very unlikely that this action of histamine has any physiologic significance

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

    International Nuclear Information System (INIS)

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

    1988-01-01

    Exposure of rats to 1-15 Gy gamma radiation ( 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

  12. 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

  13. Comparison of the tumor inhibiting effects of three histamine H2-receptor antagonists.

    Science.gov (United States)

    Tutton, P J; Barkla, D H

    1983-01-01

    Three histamine H2-receptor antagonists, Cimetidine, Metiamide and Ranitidine, were tested for their inhibitory effect on two experimental bowel cancer models. In the first model mitotic rates were measured in dimethylhydrazine-induced tumors of rat colon and in the second model volumetric changes in human large bowel cancer xenografts were assessed. In tumors of rat colon all three drugs were able to suppress mitotic activity, but the effects of Metiamide and Ranitidine were more prolonged than that of Cimetidine in each of two lines of human bowel cancer that were used. Metiamide and Ranitidine were also more effective growth inhibitors than was Cimetidine.

  14. Histamine H3 receptor ligands in the group of (homo)piperazine derivatives.

    Science.gov (United States)

    Szczepanska, Katarzyna; Kuder, Kamil; Kiec-Kononowicz, Katarzyna

    2017-11-23

    Since its' discovery in 1983, followed by gene cloning in 1999, the histamine H3 receptor served as an outstanding target for drug discovery. The wide spectrum of possible therapeutic implications make H3R's one of the most researched areas in the vast GPCR ligands field - started from imidazole containing ligands, through various successful imidazole replacements, with recent introduction of Wakix® to pharmaceutical market. One of such replacements is piperazine moiety, a significant versatile scaffold in rational drug design for most of the GPCR ligands. Therefore, herein we review ligands built on piperazine, as well as its seven membered analogue azepine, that target H3R's and their potential therapeutical applications, in order to elucidate the current state of the art in this vast field. Due to a high level of structural divergence among compounds described herein, we decided to divide them into groups, where the key division element was the position of nitrogen basicity decreasing moieties in (homo)piperazine ring. Paying attention to a number of published structures and their overall high biological activity, one can realize that the (homo)piperazine scaffold bids a versatile template also for histamine H3 receptor ligands. With two possible substitution sites and therefore a number of possible structural combinations, piperazine derivatives stand as one of the largest group of high importance among H3R ligands. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  15. Potentiation of the gastric antisecretory activity of histamine H2-receptor antagonists by clebopride.

    Science.gov (United States)

    Fernández, A G; Massingham, R; Roberts, D J

    1988-05-01

    The substituted benzamide, clebopride, at doses (0.03-3 mg kg-1 i.p.) that were without effect per se on the secretion of gastric acid in pylorus ligated (Shay) rats, potentiated the antisecretory effects of the histamine H2 receptor antagonists cimetidine and ranitidine in this model but not those of the muscarine receptor antagonist pirenzepine nor those of the proton pump inhibitor omeprazole. By contrast, clebopride was without influence on the inhibitory effects of cimetidine on pentagastrin-induced secretion in perfused stomach (Ghosh and Schild) preparations in anaesthetized rats. The significance of these findings is discussed in relation to the previously described potentiating effects of clebopride on the anti-ulcer activity of cimetidine in various experimental models, and the potential beneficial effects of such combined therapy in the clinic.

  16. Effects of a histamine H4 receptor antagonist on cisplatin-induced anorexia in mice.

    Science.gov (United States)

    Yamamoto, Kouichi; Okui, Rikuya; Yamatodani, Atsushi

    2018-04-12

    Cancer chemotherapy often induces gastrointestinal symptoms such as anorexia, nausea, and vomiting. Antiemetic agents are effective in inhibiting nausea and vomiting, but patients still experience anorexia. We previously reported that chemotherapeutic agent-induced anorexia is associated with an increase of inflammatory cytokines. Other studies also reported that antagonism of the histamine H 4 receptor is anti-inflammatory. In this study, we investigated the involvement of the H 4 receptor in the development of chemotherapy-induced anorexia in mice. Cisplatin-induced anorexia occurred within 24 h of its administration and continued for 3 days. The early phase (day 1), but not the delayed phase (days 2 and 3), of anorexia was inhibited by the daily injection of a 5-HT 3 receptor antagonist (granisetron). However, a corticosteroid (dexamethasone) or selective H 4 receptor antagonist (JNJ7777120) abolished the delayed phases of anorexia. Cisplatin significantly increased TNF-α mRNA expression in the hypothalamus and spleen, and the period of expression increase paralleled the onset period of anorexia. In addition, pretreatment with JNJ7777120 completely inhibited the increased expression. These results suggest that TNF-α mRNA expression via H 4 receptors may contribute to the development of cisplatin-induced anorexia, and that H 4 receptor antagonists are potentially useful treatments. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Histamine-imprinted microspheres: Comparison between conventional and raft-mediated polymerization techniques

    International Nuclear Information System (INIS)

    Romano, Edwin F. Jr.; So, Regina C.; Holdsworth, Clovia I.

    2015-01-01

    Molecularly imprinted microspheres (MIM) were synthesized via conventional free radical polymerization (CTP) and RAFT-mediated controlled radical polymerization (CRP) method using histamine as the template molecule. Optimal polymerization conditions were achieved using 4%(w/w) monomer feed concentration with 80=90% EGDMA as crosslinker, and histamine: MAA ratio of 1:4 in acetonitrile at 60°C for 24 hours. The size of CTP-M90 and CTP-M80 imprinted microspheres are comparable with that of RAFT polymer CRP-M80 at 264.5 ±12 nm in the swollen (DLS-DMSO) and collapsed state (SEM). For the CTP method, the presence of the template allows for a bigger particle size compared to the non-imprinted counterpart (NIM). Further, controlled growth was observed for the CRP technique, where the size of the imprinted microsphere, CRP-M80, is comparable to CRP-N80. The binding studies of CTP and CRP microspheres toward histamine were studied at concentrations well below biding with buffer concentration of 25mM at pH7. Results showed that the binding isotherms were found to conform to the Freundlich model. Moreover, results revealed that the difference in binding capacity (N) between MIM and NIM imparted by the imprinting process is significantly higher in CTP-80 (26 μmol/g) than both CTP-90 and CRP-80 (9 μmol/g). Non-competitive and competitive binding assays with L-histidine, imidazole, and tryptamine using CTP-80 and CRP-80 were also carried out. MIMs were shown to exhibit binding preference towards the template. (author)

  18. Aspirin Augments IgE-Mediated Histamine Release from Human Peripheral Basophils via Syk Kinase Activation

    Directory of Open Access Journals (Sweden)

    Hiroaki Matsuo

    2013-01-01

    Conclusions: 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.

  19. Pharmacological and functional characterisation of the wild-type and site-directed mutants of the human H1 histamine receptor stably expressed in CHO cells.

    Science.gov (United States)

    Moguilevsky, N; Varsalona, F; Guillaume, J P; Noyer, M; Gillard, M; Daliers, J; Henichart, J P; Bollen, A

    1995-01-01

    A cDNA clone for the human histamine H1 receptor was isolated from a lung cDNA library and stably expressed in CHO cells. The recombinant receptor protein present in the cell membranes, displayed the functional and binding characteristics of histamine H1 receptors. Mutation of Ser155 to Ala in the fourth transmembrane domain did not significantly change the affinity of the receptor for histamine and H1 antagonists. However, mutation of the fifth transmembrane Asn198 to Ala resulted in a dramatic decrease of the affinity for histamine binding, and for the histamine-induced polyphosphoinositides breakdown, whereas the affinity towards antagonists was not significantly modified. In addition, mutation of another fifth transmembrane amino acid, Thr194 to Ala also diminished, but to a lesser extent, the affinity for histamine. These data led us to propose a molecular model for histamine interaction with the human H1 receptor. In this model, the amide moiety of Asn198 and the hydroxyl group of Thr194 are involved in hydrogen bonding with the nitrogen atoms of the imidazole ring of histamine. Moreover, mutation of Thr194 to Ala demonstrated that this residue is responsible for the discrimination between enantiomers of cetirizine.

  20. Histamine H3 Receptors Decrease Dopamine Release in the Ventral Striatum by Reducing the Activity of Striatal Cholinergic Interneurons.

    Science.gov (United States)

    Varaschin, Rafael Koerich; Osterstock, Guillaume; Ducrot, Charles; Leino, Sakari; Bourque, Marie-Josée; Prado, Marco A M; Prado, Vania Ferreira; Salminen, Outi; Rannanpää Née Nuutinen, Saara; Trudeau, Louis-Eric

    2018-04-15

    Histamine H 3 receptors are widely distributed G i -coupled receptors whose activation reduces neuronal activity and inhibits release of numerous neurotransmitters. Although these receptors are abundantly expressed in the striatum, their modulatory role on activity-dependent dopamine release is not well understood. Here, we observed that histamine H 3 receptor activation indirectly diminishes dopamine overflow in the ventral striatum by reducing cholinergic interneuron activity. Acute brain slices from C57BL/6 or channelrhodopsin-2-transfected DAT-cre mice were obtained, and dopamine transients evoked either electrically or optogenetically were measured by fast-scan cyclic voltammetry. The H 3 agonist α-methylhistamine significantly reduced electrically- evoked dopamine overflow, an effect blocked by the nicotinic acetylcholine receptor antagonist dihydro-β-erythroidine, suggesting involvement of cholinergic interneurons. None of the drug treatments targeting H 3 receptors affected optogenetically evoked dopamine overflow, indicating that direct H 3 -modulation of dopaminergic axons is unlikely. Next, we used qPCR and confirmed the expression of histamine H 3 receptor mRNA in cholinergic interneurons, both in ventral and dorsal striatum. Activation of H 3 receptors by α-methylhistamine reduced spontaneous firing of cholinergic interneurons in the ventral, but not in the dorsal striatum. Resting membrane potential and number of spontaneous action potentials in ventral-striatal cholinergic interneurons were significantly reduced by α-methylhistamine. Acetylcholine release from isolated striatal synaptosomes, however, was not altered by α-methylhistamine. Together, these results indicate that histamine H 3 receptors are important modulators of dopamine release, specifically in the ventral striatum, and that they do so by decreasing the firing rate of cholinergic neurons and, consequently, reducing cholinergic tone on dopaminergic axons. Copyright © 2018 IBRO

  1. The modulatory role of spinally located histamine receptors in the regulation of the blood glucose level in d-glucose-fed mice.

    Science.gov (United States)

    Sim, Yun-Beom; Park, Soo-Hyun; Kim, Sung-Su; Kim, Chea-Ha; Kim, Su-Jin; Lim, Su-Min; Jung, Jun-Sub; Ryu, Ohk-Hyun; Choi, Moon-Gi; Suh, Hong-Won

    2014-02-01

    The possible roles of spinal histamine receptors in the regulation of the blood glucose level were studied in ICR mice. Mice were intrathecally (i.t.) treated with histamine 1 (H1) receptor agonist (2-pyridylethylamine) or antagonist (cetirizine), histamine 2 (H2) receptor agonist (dimaprit) or antagonist (ranitidine), histamine 3 (H3) receptor agonist (α-methylhistamine) or antagonist (carcinine) and histamine 4 (H4) receptor agonist (VUF 8430) or antagonist (JNJ 7777120), and the blood glucose level was measured at 30, 60 and 120 min after i.t. administration. The i.t. injection with α-methylhistamine, but not carcinine slightly caused an elevation of the blood glucose level. In addition, histamine H1, H2, and H4 receptor agonists and antagonists did not affect the blood glucose level. In D-glucose-fed model, i.t. pretreatment with cetirizine enhanced the blood glucose level, whereas 2-pyridylethylamine did not affect. The i.t. pretreatment with dimaprit, but not ranitidine, enhanced the blood glucose level in D-glucose-fed model. In addition, α-methylhistamine, but not carcinine, slightly but significantly enhanced the blood glucose level D-glucose-fed model. Finally, i.t. pretreatment with JNJ 7777120, but not VUF 8430, slightly but significantly increased the blood glucose level. Although histamine receptors themselves located at the spinal cord do not exert any effect on the regulation of the blood glucose level, our results suggest that the activation of spinal histamine H2 receptors and the blockade of spinal histamine H1 or H3 receptors may play modulatory roles for up-regulation and down-regulation, respectively, of the blood glucose level in D-glucose fed model.

  2. 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.

  3. 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.

  4. 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.

  5. Biochemical and ultrastructural studies suggest that the effects of thapsigargin on human platelets are mediated by changes in intracellular calcium but not by intracellular histamine

    DEFF Research Database (Denmark)

    Saxena, S P; McNicol, A; Becker, A B

    1992-01-01

    of DPPE on Tg-induced aggregation were not reversed by the addition of histamine to saponin-permeabilized platelets suggesting non-histamine mediated effects of DPPE on Tg-induced aggregation. Tg stimulated an increase in the cytosolic free calcium concentration which was unaffected by DPPE indicating...

  6. In vivo pharmacological profile of S 38093, a novel histamine H3 receptor inverse agonist.

    Science.gov (United States)

    Panayi, Fany; Sors, Aurore; Bert, Lionel; Martin, Brigitte; Rollin-Jego, Gaelle; Billiras, Rodolphe; Carrié, Isabelle; Albinet, Karine; Danober, Laurence; Rogez, Nathalie; Thomas, Jean-Yves; Pira, Luigi; Bertaina-Anglade, Valérie; Lestage, Pierre

    2017-05-15

    S 38093, a novel histamine H3 receptor inverse agonist, was tested in a series of neurochemical and behavioral paradigms designed to evaluate its procognitive and arousal properties. In intracerebral microdialysis studies performed in rats, S 38093 dose-dependently increased histamine extracellular levels in the prefrontal cortex and facilitated cholinergic transmission in the prefrontal cortex and hippocampus of rats after acute and chronic administration (10mg/kg i.p.). Acute oral administration of S 38093 at 0.1mg/kg significantly improved spatial working memory in rats in the Morris water maze test. The compound also displayed cognition enhancing properties in the two-trial object recognition task in rats, in a natural forgetting paradigm at 0.3 and 1mg/kg p.o. and in a scopolamine-induced memory deficit situation at 3mg/kg p.o. The property of S 38093 to promote episodic memory was confirmed in a social recognition test in rats at 0.3 and 1mg/kg i.p. Arousal properties of S 38093 were assessed in freely moving rats by using electroencephalographic recordings: at 3 and 10mg/kg i.p., S 38093 significantly reduced slow wave sleep delta power and induced at the highest dose a delay in sleep latency. S 38093 at 10mg/kg p.o. also decreased the barbital-induced sleeping time in rats. Taken together these data indicate that S 38093, a novel H3 inverse agonist, displays cognition enhancing at low doses and arousal properties at higher doses in rodents. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Mutational analysis of the antagonist-binding site of the histamine H(1) receptor.

    Science.gov (United States)

    Wieland, K; Laak, A M; Smit, M J; Kühne, R; Timmerman, H; Leurs, R

    1999-10-15

    We combined in a previously derived three-dimensional model of the histamine H(1) receptor (Ter Laak, A. M., Timmerman, H., Leurs, H., Nederkoorn, P. H. J., Smit, M. J., and Donne-Op den Kelder, G. M. (1995) J. Comp. Aid. Mol. Design. 9, 319-330) a pharmacophore for the H(1) antagonist binding site (Ter Laak, A. M., Venhorst, J., Timmerman, H., and Donné-Op de Kelder, G. M. (1994) J. Med. Chem. 38, 3351-3360) with the known interacting amino acid residue Asp(116) (in transmembrane domain III) of the H(1) receptor and verified the predicted receptor-ligand interactions by site-directed mutagenesis. This resulted in the identification of the aromatic amino acids Trp(167), Phe(433), and Phe(436) in transmembrane domains IV and VI of the H(1) receptor as probable interaction points for the trans-aromatic ring of the H(1) antagonists. Subsequently, a specific interaction of carboxylate moieties of two therapeutically important, zwitterionic H(1) antagonists with Lys(200) in transmembrane domain V was predicted. A Lys(200) --> Ala mutation results in a 50- (acrivastine) to 8-fold (d-cetirizine) loss of affinity of these zwitterionic antagonists. In contrast, the affinities of structural analogs of acrivastine and cetirizine lacking the carboxylate group, triprolidine and meclozine, respectively, are unaffected by the Lys(200) --> Ala mutation. These data strongly suggest that Lys(200), unique for the H(1) receptor, acts as a specific anchor point for these "second generation" H(1) antagonists.

  8. 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

    continuously with a laser Doppler flowmeter, and noradrenaline and adrenaline concentrations were determined in blood samples drawn every 15 min. The infusion of histamine caused an immediate and sustained vasodilatation. The Concomitant infusion of mepyramine prevented the immediate vasodilatation, but had...... noradrenaline, while the increase during concomitant H1-receptor blockade was delayed but achieved the level observed during the histamine infusion. The response to histamine during H2-receptor blockade was small and transient. The rise in plasma adrenaline was not significant. These findings suggest...

  9. The histamine H₃ receptor as a therapeutic drug target for metabolic disorders: status, challenges and opportunities.

    Science.gov (United States)

    Plancher, Jean-Marc

    2011-01-01

    Since the histamine-3 receptor (H₃R) was cloned in 1999, huge efforts have been made by most of the key players in the pharmaceutical industry as well as in smaller biotech companies to increase the knowledge on this peculiar receptor, with the ultimate goal of bringing new drugs to the market. This review gives a survey on the most valuable chemical tools discovered so far and the significant pharmacological experiments on metabolic disease models published to date. Pharmacology of H₃R antagonists turns out to be very complex due to various functional activities, species selectivity, presence of H₃R isoforms and the poorly understood dichotomy in efficacy between CNS and metabolic disease models. Adding an extra layer of complexity, researchers have to cope with some recurrent safety concerns, some of them being tightly linked to the nature of the H₃R pharmacophore. Therefore this review also strives to summarize the major hurdles and some of the contradictions seen in the H₃R field, together with a brief overview of the clinical trials currently running.

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Permeability of the small intestine after intra-arterial injection of histamine-type mediators and irradiation

    International Nuclear Information System (INIS)

    Kingham, J.G.C.; Loehry, C.A.

    1976-01-01

    Permeability and selectivity of rabbit small intestine were estimated by a perfusion technique after intra-arterial injection of histamine-type mediators and an intestinal dose of 1.5 Mr gamma irradiation. It was shown that the histamine-type mediators caused an increase in capillary permeability which produced an overall moderate increase in transmucosal permeability with a moderate loss of selectivity. Local intestinal irradiation caused a very marked increase in permeability and a profound loss of selectivity. It was felt that this was produced partly by an increase in capillary permeability but largely by damage to the epithelial basement membrane. It is concluded that the intestinal capillary endothelium is both rate-limiting and selective, though not to a major degree in either case. The epithelial basement membrane, however, appears to be both rate-limiting and markedly selective. (author)

  12. The Histamine H1 Receptor Participates in the Increased Dorsal Telencephalic Neurogenesis in Embryos from Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Karina H. Solís

    2017-12-01

    Full Text Available Increased neuron telencephalic differentiation during deep cortical layer formation has been reported in embryos from diabetic mice. Transitory histaminergic neurons within the mesencephalon/rhombencephalon are responsible for fetal histamine synthesis during development, fibers from this system arrives to the frontal and parietal cortex at embryo day (E 15. Histamine is a neurogenic factor for cortical neural stem cells in vitro through H1 receptor (H1R which is highly expressed during corticogenesis in rats and mice. Furthermore, in utero administration of an H1R antagonist, chlorpheniramine, decreases the neuron markers microtubuline associated protein 2 (MAP2 and forkhead box protein 2. Interestingly, in the diabetic mouse model of diabetes induced with streptozotocin, an increase in fetal neurogenesis in terms of MAP2 expression in the telencephalon is reported at E11.5. Because of the reported effects on cortical neuron differentiation of maternal diabetes in one hand and of histamine in the other, here the participation of histamine and H1R on the increased dorsal telencephalic neurogenesis was explored. First, the increased neurogenesis in the dorsal telencephalon at E14 in diabetic rats was corroborated by immunohistochemistry and Western blot. Then, changes during corticogenesis in the level of histamine was analyzed by ELISA and in H1R expression by qRT-PCR and Western blot and, finally, we tested H1R participation in the increased dorsal telencephalic neurogenesis by the systemic administration of chlorpheniramine. Our results showed a significant increase of histamine at E14 and in the expression of the receptor at E12. The administration of chlorpheniramine to diabetic rats at E12 prevented the increased expression of βIII-tubulin and MAP2 mRNAs (neuron markers and partially reverted the increased level of MAP2 protein at E14, concluding that H1R have an important role in the increased neurogenesis within the dorsal telencephalon

  13. 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...

  14. Evaluation of in vivo selective binding of [11C]doxepin to histamine H1 receptors in five animal species

    International Nuclear Information System (INIS)

    Ishiwata, Kiichi; Kawamura, Kazunori; Wang Weifang; Tsukada, Hideo; Harada, Norihiro; Mochizuki, Hideki; Kimura, Yuichi; Ishii, Kenji; Iwata, Ren; Yanai, Kazuhiko

    2004-01-01

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

  15. Progress in the development of histamine H3 receptor antagonists/inverse agonists: a patent review (2013-2017).

    Science.gov (United States)

    Łażewska, Dorota; Kieć-Kononowicz, Katarzyna

    2018-03-01

    Since years, ligands blocking histamine H 3 receptor (H 3 R) activity (antagonists/inverse agonists) are interesting targets in the search for new cures for CNS disorders. Intensive works done by academic and pharmaceutical company researchers have led to many potent and selective H 3 R antagonists/inverse agonists. Some of them have reached to clinical trials. Areas covered: Patent applications from January 2013 to September 2017 and the most important topics connected with H 3 R field are analysed. Espacenet, Patentscope, Pubmed, GoogleScholar or Cochrane Library online databases were principially used to collect all the materials. Expert opinion: The research interest in histamine H 3 R field is still high although the number of patent applications has decreased during the past 4 years (around 20 publications). Complexity of histamine H 3 R biology e.g. many isoforms, constitutive activity, heteromerization with other receptors (dopamine D 2 , D 1 , adenosine A 2A ) and pharmacology make not easy realization and evaluation of therapeutic potential of anti-H 3 R ligands. First results from clinical trials have verified potential utility of histamine H 3 R antagonist/inverse agonists in some diseases. However, more studies are necessary for better understanding of an involvement of the histaminergic system in CNS-related disorders and helping more ligands approach to clinical trials and the market. Lists of abbreviations: hAChEI - human acetylcholinesterase inhibitor; hBuChEI - human butyrylcholinesterase inhibitor; hMAO - human monoamine oxidase; MAO - monoamine oxidase.

  16. Activation of adenosine low-affinity A3 receptors inhibits the enteric short interplexus neural circuit triggered by histamine.

    Science.gov (United States)

    Bozarov, Andrey; Wang, Yu-Zhong; Yu, Jun Ge; Wunderlich, Jacqueline; Hassanain, Hamdy H; Alhaj, Mazin; Cooke, Helen J; Grants, Iveta; Ren, Tianhua; Christofi, Fievos L

    2009-12-01

    eADO acts at low-affinity A3 receptors in addition to high-affinity A1 receptors to suppress coordinated responses triggered by immune-histamine H2 receptor activation. The short interplexus circuit activated by histamine involves adenosine, acetylcholine, substance P, and serotonin. We postulate that A3 receptor modulation may occur in gut inflammatory diseases or allergic responses involving mast cell and histamine release.

  17. [11C]TASP457, a novel PET ligand for histamine H3 receptors in human brain

    International Nuclear Information System (INIS)

    Kimura, Yasuyuki; Seki, Chie; Ikoma, Yoko; Ichise, Masanori; Kawamura, Kazunori; Takahata, Keisuke; Moriguchi, Sho; Nagashima, Tomohisa; Ishii, Tatsuya; Kitamura, Soichiro; Niwa, Fumitoshi; Endo, Hironobu; Yamada, Makiko; Higuchi, Makoto; Zhang, Ming-Rong; Suhara, Tetsuya

    2016-01-01

    The histamine H 3 receptors are presynaptic neuroreceptors that inhibit the release of histamine and other neurotransmitters. The receptors are considered a drug target for sleep disorders and neuropsychiatric disorders with cognitive decline. We developed a novel PET ligand for the H 3 receptors, [ 11 C]TASP0410457 ([ 11 C]TASP457), with high affinity, selectivity and favorable kinetic properties in the monkey, and evaluated its kinetics and radiation safety profile for quantifying the H 3 receptors in human brain. Ten healthy men were scanned for 120 min with a PET scanner for brain quantification and three healthy men were scanned for radiation dosimetry after injection of 386 ± 6.2 MBq and 190 ± 7.5 MBq of [ 11 C]TASP457, respectively. For brain quantification, arterial blood sampling and metabolite analysis were performed using high-performance liquid chromatography. Distribution volumes (V T ) in brain regions were determined by compartment and graphical analyses using the Logan plot and Ichise multilinear analysis (MA1). For dosimetry, radiation absorbed doses were estimated using the Medical Internal Radiation Dose scheme. [ 11 C]TASP457 PET showed high uptake (standardized uptake values in the range of about 3 - 6) in the brain and fast washout in cortical regions and slow washout in the pallidum. The two-tissue compartment model and graphical analyses estimated V T with excellent identification using 60-min scan data (about 16 mL/cm 3 in the pallidum, 9 - 14 in the basal ganglia, 6 - 9 in cortical regions, and 5 in the pons), which represents the known distribution of histamine H 3 receptors. For parametric imaging, MA1 is recommended because of minimal underestimation with small intersubject variability. The organs with the highest radiation doses were the pancreas, kidneys, and liver. The effective dose delivered by [ 11 C]TASP457 was 6.9 μSv/MBq. [ 11 C]TASP457 is a useful novel PET ligand for the investigation of the density of histamine H 3

  18. Shifting physician prescribing to a preferred histamine-2-receptor antagonist. Effects of a multifactorial intervention in a mixed-model health maintenance organization.

    Science.gov (United States)

    Brufsky, J W; Ross-Degnan, D; Calabrese, D; Gao, X; Soumerai, S B

    1998-03-01

    This study was undertaken to determine whether a program of education, therapeutic reevaluation of eligible patients, and performance feedback could shift prescribing to cimetidine from other histamine-2 receptor antagonists, which commonly are used in the management of ulcers and reflux, and reduce costs without increasing rates of ulcer-related hospital admissions. This study used an interrupted monthly time series with comparison series in a large mixed-model health maintenance organization. Physicians employed in health centers (staff model) and physicians in independent medical groups contracting to provide health maintenance organization services (group model) participated. The comparative percentage prescribed of specific histamine-2 receptor antagonists (market share), total histamine-2 receptor antagonist prescribing, cost per histamine-2 receptor antagonist prescription, and the rate of hospitalization for gastrointestinal illness were assessed. In the staff model, therapeutic reevaluation resulted in a sudden increase in market share of the preferred histamine-2 receptor antagonist cimetidine (+53.8%) and a sudden decrease in ranitidine (-44.7%) and famotidine (-4.8%); subsequently, cimetidine market share grew by 1.1% per month. In the group model, therapeutic reevaluation resulted in increased cimetidine market share (+9.7%) and decreased prescribing of other histamine-2 receptor antagonists (ranitidine -11.6%; famotidine -1.2%). Performance feedback did not result in further changes in prescribing in either setting. Use of omeprazole, an expensive alternative, essentially was unchanged by the interventions, as were overall histamine-2 receptor antagonist prescribing and hospital admissions for gastrointestinal illnesses. This intervention, which cost approximately $60,000 to implement, resulted in estimated annual savings in histamine-2 receptor antagonist expenditures of $1.06 million. Annual savings in histamine-2 receptor antagonist expenditures

  19. Histamine H3 receptors and its antagonism as a novel mechanism for antipsychotic effect: a current preclinical & clinical perspective.

    Science.gov (United States)

    Mahmood, Danish

    2016-10-01

    Histamine H 3 receptors are present as autoreceptors on histaminergic neurons and as heteroreceptors on nonhistaminergic neurones. They control the release and synthesis of histamine and several other key neurotransmitters in the brain. H 3 antagonism may be a novel approach to develop a new class of antipsychotic medications given the gathering evidence reporting therapeutic efficacy in several central nervous system disorders. Several medications such as cariprazine, lurasidone, LY214002, bexarotene, rasagiline, raloxifene, BL-1020 and ITI-070 are being developed to treat the negative symptoms and cognitive impairments of schizophrenia. These medications works through diverse mechanisms which include agonism at metabotropic glutamate receptor (mGluR2/3), partial agonism at dopamine D 2 , D 3 and serotonin 5-HT 1A receptors, antagonism at D 2 , 5-HT 2A, 5-HT 2B and 5-HT 7 receptors, combined dopamine antagonism with GABA agonist activity, inhibition of monoamine oxidase-B, modulation of oestrogen receptor, and activation of nuclear retinoid X receptor. However, still specific safe therapy for psychosis remains at large. Schizophrenia is a severe neuropsychiatric disorder result both from hyper- and hypo-dopaminergic transmission causing positive and negative symptoms, respectively. Pharmacological stimulation of dopamine release in the prefrontal cortex has been a viable approach in treating negative symptoms and cognitive deficits of schizophrenia symptoms that are currently not well treated and continue to represent significant unmet medical challenges. Administration of H 3 antagonists/inverse agonists increase extracellular dopamine concentrations in rat prefrontal cortex, but not in the striatum suggesting that antagonism via H 3 receptor may be a potential target for treating negative symptoms and cognitive deficits associated with schizophrenia. Further, insights are emerging into the potential role of histamine H 3 receptors as a target of antiobesity

  20. Simplified PET measurement for evaluating histamine H1 receptors in human brains using [11C]doxepin

    International Nuclear Information System (INIS)

    Mochizuki, Hideki; Kimura, Yuichi; Ishii, Kenji; Oda, Keiichi; Sasaki, Toru; Tashiro, Manabu; Yanai, Kazuhiko; Ishiwata, Kiichi

    2004-01-01

    The aim of this study was to develop simplified positron emission tomography measurement using [ 11 C]doxepin ([ 11 C]DOX) to evaluate histamine H 1 receptors (H1Rs) in human brains. We evaluated the correlation between the distribution volume (DV) of [ 11 C]DOX, estimated quantitatively with a two-compartment model, and the [ 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 [ 11 C]DOX-H1R binding

  1. Histamine H3 receptor density is negatively correlated with neural activity related to working memory in humans.

    Science.gov (United States)

    Ito, Takehito; Kimura, Yasuyuki; Seki, Chie; Ichise, Masanori; Yokokawa, Keita; Kawamura, Kazunori; Takahashi, Hidehiko; Higuchi, Makoto; Zhang, Ming-Rong; Suhara, Tetsuya; Yamada, Makiko

    2018-06-14

    The histamine H 3 receptor is regarded as a drug target for cognitive impairments in psychiatric disorders. H 3 receptors are expressed in neocortical areas, including the prefrontal cortex, the key region of cognitive functions such as working memory. However, the role of prefrontal H 3 receptors in working memory has not yet been clarified. Therefore, using functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) techniques, we aimed to investigate the association between the neural activity of working memory and the density of H 3 receptors in the prefrontal cortex. Ten healthy volunteers underwent both fMRI and PET scans. The N-back task was used to assess the neural activities related to working memory. H 3 receptor density was measured with the selective PET radioligand [ 11 C] TASP457. The neural activity of the right dorsolateral prefrontal cortex during the performance of the N-back task was negatively correlated with the density of H 3 receptors in this region. Higher neural activity of working memory was associated with lower H 3 receptor density in the right dorsolateral prefrontal cortex. This finding elucidates the role of H 3 receptors in working memory and indicates the potential of H 3 receptors as a therapeutic target for the cognitive impairments associated with neuropsychiatric disorders.

  2. Involvement of histamine H1 and H2 receptors in hypothermia induced by ionizing radiation in guinea pigs

    International Nuclear Information System (INIS)

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

    1988-01-01

    Radiation-induced hypothermia was examined in guinea pigs. Exposure to the head alone or whole-body irradiation induced hypothermia, whereas exposure of the body alone produced a small insignificant response. Systemic injection of disodium cromoglycate (a mast cell stabilizer) and cimetidine (H2-receptor antagonist) had no effect on radiation-induced hypothermia, whereas systemic and central administration of mepyramine (H1-receptor antagonist) or central administration of disodium cromoglycate or cimetidine attenuated it, indicating the involvement of central histamine through both H1 and H2 receptors in this response. Serotonin is not involved, since the serotonin antagonist methysergide had no effect on radiation-induced hypothermia. These results indicate that central histaminergic systems may be involved in radiation-induced hypothermia. 34 references, 5 figures, 2 tables

  3. Effects of Bidens pilosa L. var. radiata SCHERFF treated with enzyme on histamine-induced contraction of guinea pig ileum and on histamine release from mast cells.

    Science.gov (United States)

    Matsumoto, Takayuki; Horiuchi, Masako; Kamata, Katsuo; Seyama, Yoshiyuki

    2009-06-01

    The medical mechanism against type I allergies is to block the release or production of chemical mediators from mast cells or to block the H(1)-receptor signaling. We previously reported that the anti-allergic action of the dry powder from Bidens pilosa L. var. radiata SCHERFF treated with the enzyme cellulosine (eMMBP) was dependent on the inhibition of histamine release from mast cells. Here, we investigate that the effect of fractions in eMMBP on the histamine-induced contraction in guinea pig ileum and on the release of histamine in rat peritoneal mast cells. The histamine-induced contraction in guinea pig ileum is dose-dependently inhibited by ketotifen, an antagonist of H(1)-receptor. Fractions contained caffeic acid, caffeoylquinic acid and fractions contained flavonoids such as hyperin and isoquercitrin in eMMBP inhibit histamine release from mast cells, but only flavonoids such as hyperin, isoquercitrin and rutin suppress the histamine-induced contraction in guinea pig ileum. Moreover, the histamine-induced contraction was not affected by caffeic acid, however, such contraction was significantly inhibited by rutin. These results suggest that the primary antagonists of H(1)- receptor are different from the components in eMMBP that inhibit histamine release, and that these components participate in the anti-allergic activity of eMMBP.

  4. Further studies on the structural requirements for mast cell degranulating (MCD) peptide-mediated histamine release.

    Science.gov (United States)

    Buku, A; Price, J A

    2001-12-01

    Mast cell degranulating (MCD) peptide was modified in its two disulfide bridges and in the two arginine residues in order to measure the ability of these analogs to induce histamine release from mast cells in vitro. Analogs prepared were [Ala(3,15)]MCD, [Ala(5,19)]MCD, [Orn(16)]MCD, and [Orn(7,16)]MCD. Their histamine-releasing activity was determined spectrofluorometrically with peritoneal mast cells. The monocyclic analogs in which the cysteine residues were replaced pairwise with alanine residues showed three-to ten-fold diminished histamine-releasing activity respectively, compared with the parent MCD peptide. Substantial increases in activity were observed where arginine residues were replaced by ornithines. The ornithine-mono substituted analog showed an almost six-fold increase and the ornithine-doubly substituted analog three-fold increase in histamine-releasing activity compared with the parent MCD peptide. The structural changes associated with these activities were followed by circular dichroism (CD) spectroscopy. Changes in the shape and ellipticity of the CD spectra reflected a role for the disulfide bonds and the two arginine residues in the overall conformation and biological activity of the molecule.

  5. The Histamine H3 Receptor Antagonist DL77 Ameliorates MK801-Induced Memory Deficits in Rats

    Directory of Open Access Journals (Sweden)

    Nermin Eissa

    2018-02-01

    Full Text Available The role of Histamine H3 receptors (H3Rs in memory, and the prospective of H3R antagonists in pharmacological control of neurodegenerative disorders, e.g., Alzheimer disease (AD is well-accepted. For that reason, the procognitive effects of the H3R antagonist DL77 on cognitive impairments induced with MK801 were tested in an inhibitory passive avoidance paradigm (PAP and novel object recognition (NOR task in adult male rats, using donepezil (DOZ as a standard drug. Acute systemic pretreatment with DL77 (2.5, 5, and 10 mg/kg, i.p. significantly ameliorated memory deficits induced with MK801 in PAP (all P < 0.05, n = 7. The ameliorative effect of most promising dose of DL77 (5 mg/kg, i.p. was reversed when rats were co-injected with the H3R agonist R-(α-methylhistamine (RAMH, 10 mg/kg, i.p. (p = 0.701 for MK801-amnesic group vs. MK801+DL77+RAMH group, n = 6. In the NOR paradigm, DL77 (5 mg/kg, i.p. counteracted long-term memory (LTM deficits induced with MK801 (P < 0.05, n = 6–8, and the DL77-provided effect was similar to that of DOZ (p = 0.788, n = 6–8, and was reversed when rats were co-injected with RAMH (10 mg/kg, i.p. (p = 0.877, n = 6, as compared to the (MK801-amnesic group. However, DL77 (5 mg/kg, i.p. did not alter short-term memory (STM impairment in NOR test (p = 0.772, n = 6–8, as compared to (MK801-amnesic group. Moreover, DL77 (5 mg/kg failed to modify anxiety and locomotor behaviors of animals innate to elevated-plus maze (EPM (p = 0.67 for percentage of time spent exploring the open arms, p = 0.52 for number of entries into the open arms, p = 0.76 for percentage of entries into the open arms, and p = 0.73 number of closed arm entries as compared to saline-treated groups, all n = 6, demonstrating that the procognitive effects observed in PAP or NOR tests were unconnected to alterations in emotions or in natural locomotion of tested animals. These results signify the potential involvement of H3Rs in modulating

  6. 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.

  7. (11)C-MK-8278 PET as a tool for pharmacodynamic brain occupancy of histamine 3 receptor inverse agonists.

    Science.gov (United States)

    Van Laere, Koenraad J; Sanabria-Bohórquez, Sandra M; Mozley, David P; Burns, Donald H; Hamill, Terence G; Van Hecken, Anne; De Lepeleire, Inge; Koole, Michel; Bormans, Guy; de Hoon, Jan; Depré, Marleen; Cerchio, Kristine; Plalcza, John; Han, Lingling; Renger, John; Hargreaves, Richard J; Iannone, Robert

    2014-01-01

    The histamine 3 (H3) receptor is a presynaptic autoreceptor in the central nervous system that regulates the synthesis and release of histamine and modulates the release of other major neurotransmitters. H3 receptor inverse agonists (IAs) may be efficacious in the treatment of various central nervous system disorders, including excessive daytime sleepiness, attention deficit hyperactivity disorder, Alzheimer disease, ethanol addiction, and obesity. Using PET and a novel high-affinity and selective radioligand (11)C-MK-8278, we studied the tracer biodistribution, quantification, and brain H3 receptor occupancy (RO) of MK-0249 and MK-3134, 2 potential IA drugs targeting cerebral H3 receptors, in 6 healthy male subjects (age, 19-40 y). The relationship among H3 IA dose, time on target, and peripheral pharmacokinetics was further investigated in 15 healthy male volunteers (age, 18-40 y) with up to 3 PET scans and 3 subjects per dose level. The mean effective dose for (11)C-MK-8278 was 5.4 ± 1.1 μSv/MBq. Human brain kinetics showed rapid high uptake and fast washout. Binding potential values can be assessed using the pons as a reference region, with a test-retest repeatability of 7%. Drug RO data showed low interindividual variability per dose (mean RO SD, 2.1%), and a targeted 90% RO can be reached for both IAs at clinically feasible doses. (11)C-MK-8278 is a useful novel PET radioligand for determination of human cerebral H3 receptor binding and allows highly reproducible in vivo brain occupancy of H3-targeting drugs, hereby enabling the evaluation of novel compounds in early development to select doses and schedules.

  8. Molecular Regulation of Histamine Synthesis

    Directory of Open Access Journals (Sweden)

    Hua Huang

    2018-06-01

    Full Text Available Histamine is a critical mediator of IgE/mast cell-mediated anaphylaxis, a neurotransmitter and a regulator of gastric acid secretion. Histamine is a monoamine synthesized from the amino acid histidine through a reaction catalyzed by the enzyme histidine decarboxylase (HDC, which removes carboxyl group from histidine. Despite the importance of histamine, transcriptional regulation of HDC gene expression in mammals is still poorly understood. In this review, we focus on discussing advances in the understanding of molecular regulation of mammalian histamine synthesis.

  9. Identification of novel β-lactams and pyrrolidinone derivatives as selective Histamine-3 receptor (H3R) modulators as possible anti-obesity agents.

    Science.gov (United States)

    Ghoshal, Anirban; Kumar, Ajeet; Yugandhar, Doddapaneni; Sona, Chandan; Kuriakose, Sunu; Nagesh, Kommu; Rashid, Mamunur; Singh, Sandeep K; Wahajuddin, Muhammad; Yadav, Prem N; Srivastava, Ajay K

    2018-05-25

    Four series of structurally related β-lactams, 2,5-pyrrolidinediones, azaspirodecatrienediones (ASDT) and dihydropyrroloquinoxalinetriones (DPQT) were synthesized by utilizing post-Ugi modifications in one-pot, and their activity towards human histamine-3 receptor (H3R) was evaluated. Out of 94 compounds, screened against histamine-3 receptor (H3R), 21 compounds showed high H3R selective agonist property with EC 50 values ranging from 187 nM to 0.1 nM, whereas none of the compound was found to have the affinity towards other receptors of histamine family such as histamine H1, H2, and H4 receptor. All active compounds have no assay interference activity as determined by in-silico analysis and receptor independent luciferase assay and cell cytotoxicity assay. Given the important role of H3R in hypophagia, we also evaluated the in vivo effect of the representative compound 6k on the cumulative food intake in diet induce obese C57BL6/J mice. Interestingly, we observed that single dose administration (20 mg/kg, intraperitoneal injection) of 6k significantly suppressed cumulative food intake, while no significant effect was observed at 10 mg/kg. These results suggest that β-lactams, 2,5-pyrrolidinediones, azaspirodecatrienediones (ASDT) and dihydropyrroloquinoxalinetriones (DPQT) could be useful for the development of anti-obesity candidate drugs. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  10. 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...

  11. Distinct signalling pathways of murine histamine H1- and H4-receptors expressed at comparable levels in HEK293 cells.

    Directory of Open Access Journals (Sweden)

    Silke Beermann

    Full Text Available Histamine (HA is recognized by its target cells via four G-protein-coupled receptors, referred to as histamine H1-receptor (H1R, H2R, H3R, and H4R. Both H1R and H4R exert pro-inflammatory functions. However, their signal transduction pathways have never been analyzed in a directly comparable manner side by side. Moreover, the analysis of pharmacological properties of the murine orthologs, representing the main targets of pre-clinical research, is very important. Therefore, we engineered recombinant HEK293 cells expressing either mouse (mH1R or mH4R at similar levels and analyzed HA-induced signalling in these cells. HA induced intracellular calcium mobilization via both mH1R and mH4R, with the mH1R being much more effective. Whereas cAMP accumulation was potentiated via the mH1R, it was reduced via the mH4R. The regulation of both second messengers via the H4R, but not the H1R, was sensitive to pertussis toxin (PTX. The mitogen-activated protein kinases (MAPKs ERK 1/2 were massively activated downstream of both receptors and demonstrated a functional involvement in HA-induced EGR-1 gene expression. The p38 MAPK was moderately activated via both receptors as well, but was functionally involved in HA-induced EGR-1 gene expression only in H4R-expressing cells. Surprisingly, in this system p38 MAPK activity reduced the HA-induced gene expression. In summary, using this system which allows a direct comparison of mH1R- and mH4R-induced signalling, qualitative and quantitative differences on the levels of second messenger generation and also in terms of p38 MAPK function became evident.

  12. Is a positive intracutaneous test induced by penicillin mediated by histamine?

    DEFF Research Database (Denmark)

    Tannert, Line K; Falkencrone, Sidsel; Mortz, Charlotte G

    2017-01-01

    Background: Diagnostic workup of penicillin allergy comprises skin testing with penicillins, and patients are deemed allergic if skin test is positive. However, the literature suggests that skin test-positive patients may be challenge-negative, indicating that the skin test may be falsely positive....... Objective: To investigate real-time histamine release from a positive intracutaneous test induced by penicillin in patients with positive and negative challenges to penicillin. Methods: Skin microdialysis was performed in 21 penicillin-allergic patients with positive skin test, 13 non-allergic volunteers...... serving as negative controls, and 7 grass pollen-allergic patients serving as positive controls. Histamine was measured by microdialysis after skin test with penicillin/grass/NaCl. Penicillin challenge was subsequently performed in 12 of the patients. Results: Only 10/21 patients (47.6%) were skin test...

  13. Histamine mediates the pro-inflammatory effect of latex of Calotropis procera in rats

    Directory of Open Access Journals (Sweden)

    Yatin M. Shivkar

    2003-01-01

    Full Text Available Introduction: Calotropis procera is known to produce contact dermatitis and the latex of this plant produces intense inflammation when injected locally. However, the precise mode of its pro-inflammatory effect is not known. In present study we have pharmacologically characterized the inflammation induced by latex of C. procera in a rat paw edema model and determined the role of histamine in latex-induced inflammation.

  14. Activation of Microglia by Histamine and Substance P

    Directory of Open Access Journals (Sweden)

    Jin Zhu

    2014-08-01

    Full Text Available Background: Activated microglia perform many of the immune effector functions typically associated with macrophages. However, the regulators involved in microglial activation are not well defined. Because microglia play a pivotal role in immune surveillance of the CNS, we studied the effect of the neuromediators histamine and substance P on microglia. Methods: The induction of microglial activation by histamine and substance P was examined using primary cultured microglia. Fluorescent images were acquired with a confocal microscope. The levels of TNF-α and IL-6 were measured with a commercial ELISA kit. Intracellular reactive oxygen species (ROS levels were determined by dichlorodihydrofluorescein oxidation. The mitochondrial membrane potential was assessed with the MitoProbe™ JC-1 assay kit. Results: We found that the neuromediators histamine and substance P were able to stimulate microglial activation and the subsequent production of ROS and proinflammatory factors TNF-α and IL-6. These effects were partially abolished by antagonists of the histamine receptors H1 and H4 and of the substance P receptors NK-1, NK-2 and NK-3. Histamine induced mitochondrial membrane depolarization in microglia. Conclusions: These results indicate that the neuromediators histamine and SP can trigger microglial activation and release of pro-inflammatory factors from microglia, thus contributing to the development of microglia-mediated inflammation in the brain.

  15. Structure-based prediction of subtype selectivity of histamine H3 receptor selective antagonists in clinical trials.

    Science.gov (United States)

    Kim, Soo-Kyung; Fristrup, Peter; Abrol, Ravinder; Goddard, William A

    2011-12-27

    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 H(3) histamine receptor (hH(3)HR) antagonists have been proposed for specific therapeutic applications, including treatment of Alzheimer's disease, attention deficit hyperactivity disorder (ADHD), epilepsy, and obesity. 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 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 (H(1), H(2), H(3), and H(4)) using the GEnSeMBLE (GPCR ensemble of structures in membrane bilayer environment) Monte Carlo protocol, sampling ∼35 million combinations of helix packings to predict the 10 most stable packings for each of the four subtypes. Then we used these 10 best protein structures with the DarwinDock Monte Carlo protocol to sample ∼50 000 × 10(20) poses to predict the optimum ligand-protein structures for various agonists and antagonists. We find that E206(5.46) contributes most in binding H(3) selective agonists (5, 6, 7) in agreement with experimental mutation studies. We also find that conserved E5.46/S5.43 in both of hH(3)HR and hH(4)HR are involved in H(3)/ H(4) subtype selectivity. In addition, we find that M378(6.55) in hH(3)HR provides additional hydrophobic interactions different from hH(4)HR (the corresponding amino acid of T323(6.55) in hH(4)HR) to provide additional subtype bias. From these studies, we developed a pharmacophore model based on our predictions for known hH(3)HR selective antagonists in clinical study [ABT-239 1, GSK-189,254 2, PF-3654746 3, and BF2.649 (tiprolisant) 4] that suggests critical selectivity directing elements are: the basic proton

  16. 11C-labeled and 18F-labeled PET ligands for subtype-specific imaging of histamine receptors in the brain

    NARCIS (Netherlands)

    Funke, U.; Vugts, D.J.; Janssen, B.; Spaans, A.; Kruijer, P.S.; Lammertsma, A.A.; Perk, L.R.; Windhorst, A.D.

    2013-01-01

    The signaling molecule histamine plays a key role in the mediation of immune reactions, in gastric secretion, and in the sensory system. In addition, it has an important function as a neurotransmitter in the central nervous system, acting in pituitary hormone secretion, wakefulness, motor and

  17. 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.

  18. Acute exposure to high-peak-power pulsed microwaves affecting the histamine H3 receptor expression in rat hippocampus

    International Nuclear Information System (INIS)

    Yu Xiaodong; Li Bo; Li Dehua; He Qiyi; Yu Zhengping

    2006-01-01

    In the Morris Water test, high-peak-power pulsed microwave (MW)-exposed rats displayed some learning and memory behavior dysfunctions, and their escape time and swimming distance to the submerged platform were longer than those of the sham-exposed rats. to understand the molecular mechanism involved, the reverse transcription-polymerase chain reation (RT-PCR) and the Western-blotting technique were used for investigating the mRNA and protein expression patterns of the histamine H 3 receptor (H 3 R) in rat hippocampus. High-peak-power pulsed microwave-exposure did not remarkably lead to the change in expression of H 3 R mRNA in rat hippocampi; however, it promoted the up-regulatory expression of the H 3 R protein, which was possibly triggered through the mitogen-activated protein kinase (MAPK) pathways. Therefore, further investigation of the molecular mechanism of the MW effects on the learning and memory behaviors is required. (authors)

  19. Basophil histamine release to Amoxicilloyl-poly-L-lysine compared to amoxicillin in patients with IgE-mediated allergic reactions to amoxicillin

    DEFF Research Database (Denmark)

    Arribas, F; Falkencrone, S; Sola, J

    2017-01-01

    BACKGROUND: Amoxicillin (AX) is the betalactam most often involved in IgE-mediated reactions and the diagnosis is mainly based on skin testing (ST) although without optimal sensitivity. We have produced a newly AX derivative, amoxicilloyl-poly-L-lysine (APL), and have analysed its IgE recognition...... with AX or APL. Histamine released was determined and expressed as ng of histamine release/mL blood. RESULTS: Patients clinical symptoms were anaphylaxis (N=9), urticaria (N=7), erythema (N=2) and not defined immediate reactions (N=1). The median time interval between reaction and study was 90 days (IQR...

  20. 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

  1. Radioprotective effects of histamine H2 receptor antagonists famotidine and ranitidine on gamma ray induced chromosome damage

    International Nuclear Information System (INIS)

    Sharma, N.K.

    2013-01-01

    Histamine H2 receptor antagonist such as Cimetidine, Famotidine and Ranitidine are used in the clinical treatment of peptic ulcer. In vitro metaphase analysis and micronucleus assay were used to test the effects of famotidine and ranitidine on Cobalt 60 γ-ray induced clastogenic effects. Heparinised whole blood was obtained from healthy non-smoker volunteers. Blood samples were irradiated at a dose of 3Gy and incubated at 37 deg C for 1h. Lymphocyte cultures were initiated for metaphase chromosomes and cytochalasin B blocked micronucleus analysis. Aqueous solution of Famotidine (150 g/ml) and Ranitidine (500 g/ml) was added to the whole blood cultures at 0h and 24h. Cultures were harvested and processed at 48h and 72h for chromosome aberrations and micronucleus analysis respectively. Cultures treated with Famotidine at 0h and 24h after 3Gy γ-ray irradiation induce 60.90% and 56.52% inhibition in dicentrics, 48.70% and 43.61% inhibition in total aberrations. Ranitidine at 0h and 24h after 3Gy γ-ray irradiation induce 52.17% and 43.47% inhibition in dicentrics, 33.60% and 46.15% inhibition in total aberrations, when compared with 3Gy γ-ray irradiation alone. 43-54% inhibition in Binucleated cells with micronuclei and 47.72% inhibition in micronuclei at 0h treatment respectively. In conclusion radioprotective effects of Histamine H2 receptor antagonists famotidine and ranitidine on γ-ray induced chromosome damage is observed and the drugs effectively reduced the frequency of radiation induced chromosome aberrations and micronucleus. Famotidine was found to be more effective. The mechanism in which these drugs reduce clastogenic effect of γ-radiation is not fully understood. It might be due to their antioxidant and free radical-scavenging properties. (author)

  2. Synthesis of Gallic Acid Analogs as Histamine and Pro-Inflammatory Cytokine Inhibitors for Treatment of Mast Cell-Mediated Allergic Inflammation.

    Science.gov (United States)

    Fei, Xiang; Je, In-Gyu; Shin, Tae-Yong; Kim, Sang-Hyun; Seo, Seung-Yong

    2017-05-29

    Gallic acid (3,4,5-trihydroxybenzoic acid), is a natural product found in various foods and herbs that are well known as powerful antioxidants. Our previous report demonstrated that it inhibits mast cell-derived inflammatory allergic reactions by blocking histamine release and pro-inflammatory cytokine expression. In this report, various amide analogs of gallic acid have been synthesized by introducing different amines through carbodiimide-mediated amide coupling and Pd/C-catalyzed hydrogenation. These compounds showed a modest to high inhibitory effect on histamine release and pro-inflammatory cytokine expression. Among them, the amide bearing ( S )-phenylglycine methyl ester 3d was found to be more active than natural gallic acid. Further optimization yielded several ( S )- and ( R )-phenylglycine analogs that inhibited histamine release in vitro. Our findings suggest that some gallamides could be used as a treatment for allergic inflammatory diseases.

  3. Involvement of the histamine H4 receptor in clozapine-induced hematopoietic toxicity: Vulnerability under granulocytic differentiation of HL-60 cells

    International Nuclear Information System (INIS)

    Goto, Aya; Mouri, Akihiro; Nagai, Tomoko; Yoshimi, Akira; Ukigai, Mako; Tsubai, Tomomi; Hida, Hirotake; Ozaki, Norio; Noda, Yukihiro

    2016-01-01

    Clozapine is an effective antipsychotic for treatment-resistant schizophrenia, but can cause fatal hematopoietic toxicity as agranulocytosis. To elucidate the mechanism of hematopoietic toxicity induced by clozapine, we developed an in vitro assay system using HL-60 cells, and investigated the effect on hematopoiesis. HL-60 cells were differentiated by all-trans retinoic acid (ATRA) into three states according to the following hematopoietic process: undifferentiated HL-60 cells, those undergoing granulocytic ATRA-differentiation, and ATRA-differentiated granulocytic cells. Hematopoietic toxicity was evaluated by analyzing cell survival, cell proliferation, granulocytic differentiation, apoptosis, and necrosis. In undifferentiated HL-60 cells and ATRA-differentiated granulocytic cells, both clozapine (50 and 100 μM) and doxorubicin (0.2 µM) decreased the cell survival rate, but olanzapine (1–100 µM) did not. Under granulocytic differentiation for 5 days, clozapine, even at a concentration of 25 μM, decreased survival without affecting granulocytic differentiation, increased caspase activity, and caused apoptosis rather than necrosis. Histamine H 4 receptor mRNA was expressed in HL-60 cells, whereas the expression decreased under granulocytic ATRA-differentiation little by little. Both thioperamide, a histamine H 4 receptor antagonist, and DEVD-FMK, a caspase-3 inhibitor, exerted protection against clozapine-induced survival rate reduction, but not of live cell counts. 4-Methylhistamine, a histamine H 4 receptor agonist, decreased the survival rate and live cell counts, as did clozapine. HL-60 cells under granulocytic differentiation are vulnerable under in vitro assay conditions to hematopoietic toxicity induced by clozapine. Histamine H 4 receptor is involved in the development of clozapine-induced hematopoietic toxicity through apoptosis, and may be a potential target for preventing its occurrence through granulocytic differentiation. - Highlights: • HL-60

  4. Involvement of the histamine H{sub 4} receptor in clozapine-induced hematopoietic toxicity: Vulnerability under granulocytic differentiation of HL-60 cells

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Aya; Mouri, Akihiro; Nagai, Tomoko; Yoshimi, Akira; Ukigai, Mako; Tsubai, Tomomi; Hida, Hirotake [Division of Clinical Sciences and Neuropsychopharmacology, Faculty and Graduate School of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503 (Japan); Ozaki, Norio [Department of Psychiatry, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 (Japan); Noda, Yukihiro, E-mail: ynoda@meijo-u.ac.jp [Division of Clinical Sciences and Neuropsychopharmacology, Faculty and Graduate School of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503 (Japan)

    2016-09-01

    Clozapine is an effective antipsychotic for treatment-resistant schizophrenia, but can cause fatal hematopoietic toxicity as agranulocytosis. To elucidate the mechanism of hematopoietic toxicity induced by clozapine, we developed an in vitro assay system using HL-60 cells, and investigated the effect on hematopoiesis. HL-60 cells were differentiated by all-trans retinoic acid (ATRA) into three states according to the following hematopoietic process: undifferentiated HL-60 cells, those undergoing granulocytic ATRA-differentiation, and ATRA-differentiated granulocytic cells. Hematopoietic toxicity was evaluated by analyzing cell survival, cell proliferation, granulocytic differentiation, apoptosis, and necrosis. In undifferentiated HL-60 cells and ATRA-differentiated granulocytic cells, both clozapine (50 and 100 μM) and doxorubicin (0.2 µM) decreased the cell survival rate, but olanzapine (1–100 µM) did not. Under granulocytic differentiation for 5 days, clozapine, even at a concentration of 25 μM, decreased survival without affecting granulocytic differentiation, increased caspase activity, and caused apoptosis rather than necrosis. Histamine H{sub 4} receptor mRNA was expressed in HL-60 cells, whereas the expression decreased under granulocytic ATRA-differentiation little by little. Both thioperamide, a histamine H{sub 4} receptor antagonist, and DEVD-FMK, a caspase-3 inhibitor, exerted protection against clozapine-induced survival rate reduction, but not of live cell counts. 4-Methylhistamine, a histamine H{sub 4} receptor agonist, decreased the survival rate and live cell counts, as did clozapine. HL-60 cells under granulocytic differentiation are vulnerable under in vitro assay conditions to hematopoietic toxicity induced by clozapine. Histamine H{sub 4} receptor is involved in the development of clozapine-induced hematopoietic toxicity through apoptosis, and may be a potential target for preventing its occurrence through granulocytic differentiation

  5. Intra-cerebellar microinjection of histamine enhances memory consolidation of inhibitory avoidance learning in mice via H2 receptors.

    Science.gov (United States)

    Gianlorenço, A C L; Canto-de-Souza, A; Mattioli, R

    2013-12-17

    Studies have demonstrated the relationship between the histaminergic system and the cerebellum, and we intend to investigate the role of the cerebellar histaminergic system on memory consolidation. This study investigated the effect of intra-cerebellar microinjection of histamine on memory retention of inhibitory avoidance in mice, and the role of H1 and H2 receptors in it. The cerebellar vermis of male mice were implanted with guide cannulae, and after three days of recovery, the inhibitory avoidance test was performed. Immediately after a training session, animals received a microinjection of histaminergic drugs: in the experiment 1, saline (SAL) or histamine (HA 0.54, 1.36, 2.72 or 4.07 nmol); experiment 2, SAL or 1.36 nmol HA 5 min after a pretreatment with 0.16 nmol chlorpheniramine (CPA) or SAL; and experiment 3, SAL or 1.36 nmol HA 5 min after a pretreatment with 2.85 nmol ranitidine (RA) or SAL. Twenty-four hours later, a retention test was performed. The data were analyzed using one-way analysis of variance (ANOVA) and Duncan's tests. In experiment 1, animals microinjected with 1.36 nmol HA showed a higher latency to cross to the dark compartment compared to controls and to 2.72 and 4.07 nmol HA groups. In experiment 2, the combined infusions revealed difference between control (SAL+SAL) and SAL+HA and CPA+HA; while in the experiment 3 the analysis indicated differences in retention latency between mice injected with SAL+SAL and SAL+HA. The groups that received the H2 antagonist RA did not show difference compared to control. These results indicate that 1.36 nmol HA enhances memory consolidation of inhibitory avoidance learning in mice and that the pretreatment with H2 antagonist RA was able to prevent this effect. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. Regional Differential Effects of the Novel Histamine H3 Receptor Antagonist 6-[(3-Cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide hydrochloride (GSK189254) on Histamine Release in the Central Nervous System of Freely Moving Rats

    OpenAIRE

    Giannoni, Patrizia; Medhurst, Andrew D.; Passani, Maria Beatrice; Giovannini, Maria Grazia; Ballini, Chiara; Corte, Laura Della; Blandina, Patrizio

    2010-01-01

    After oral administration, the nonimidazole histamine H3 receptor antagonist, 6-[(3-cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide hydrochloride (GSK189254), increased histamine release from the tuberomammillary nucleus, where all histaminergic somata are localized, and from where their axons project to the entire brain. To further understand functional histaminergic circuitry in the brain, dual-probe microdialysis was used to pharmacologically block H3...

  7. The dual orexin receptor antagonist, DORA-22, lowers histamine levels in the lateral hypothalamus and prefrontal cortex without lowering hippocampal acetylcholine.

    Science.gov (United States)

    Yao, Lihang; Ramirez, Andres D; Roecker, Anthony J; Fox, Steven V; Uslaner, Jason M; Smith, Sean M; Hodgson, Robert; Coleman, Paul J; Renger, John J; Winrow, Christopher J; Gotter, Anthony L

    2017-07-01

    Chronic insomnia is defined as a persistent difficulty with sleep initiation maintenance or non-restorative sleep. The therapeutic standard of care for this condition is treatment with gamma-aminobutyric acid (GABA) A receptor modulators, which promote sleep but are associated with a panoply of side effects, including cognitive and memory impairment. Dual orexin receptor antagonists (DORAs) have recently emerged as an alternative therapeutic approach that acts via a distinct and more selective wake-attenuating mechanism with the potential to be associated with milder side effects. Given their distinct mechanism of action, the current work tested the hypothesis that DORAs and GABA A receptor modulators differentially regulate neurochemical pathways associated with differences in sleep architecture and cognitive performance induced by these pharmacological mechanisms. Our findings showed that DORA-22 suppresses the release of the wake neurotransmitter histamine in the lateral hypothalamus, prefrontal cortex, and hippocampus with no significant alterations in acetylcholine levels. In contrast, eszopiclone, commonly used as a GABA A modulator, inhibited acetylcholine secretion across brain regions with variable effects on histamine release depending on the extent of wakefulness induction. In normal waking rats, eszopiclone only transiently suppressed histamine secretion, whereas this suppression was more obvious under caffeine-induced wakefulness. Compared with the GABA A modulator eszopiclone, DORA-22 elicits a neurotransmitter profile consistent with wake reduction that does not impinge on neurotransmitter levels associated with cognition and rapid eye movement sleep. © 2017 International Society for Neurochemistry.

  8. Generation of a homology model of the human histamine H3 receptor for ligand docking and pharmacophore-based screening

    Science.gov (United States)

    Schlegel, Birgit; Laggner, Christian; Meier, Rene; Langer, Thierry; Schnell, David; Seifert, Roland; Stark, Holger; Höltje, Hans-Dieter; Sippl, Wolfgang

    2007-08-01

    The human histamine H3 receptor (hH3R) is a G-protein coupled receptor (GPCR), which modulates the release of various neurotransmitters in the central and peripheral nervous system and therefore is a potential target in the therapy of numerous diseases. Although ligands addressing this receptor are already known, the discovery of alternative lead structures represents an important goal in drug design. The goal of this work was to study the hH3R and its antagonists by means of molecular modelling tools. For this purpose, a strategy was pursued in which a homology model of the hH3R based on the crystal structure of bovine rhodopsin was generated and refined by molecular dynamics simulations in a dipalmitoylphosphatidylcholine (DPPC)/water membrane mimic before the resulting binding pocket was used for high-throughput docking using the program GOLD. Alternatively, a pharmacophore-based procedure was carried out where the alleged bioactive conformations of three different potent hH3R antagonists were used as templates for the generation of pharmacophore models. A pharmacophore-based screening was then carried out using the program Catalyst. Based upon a database of 418 validated hH3R antagonists both strategies could be validated in respect of their performance. Seven hits obtained during this screening procedure were commercially purchased, and experimentally tested in a [3H]Nα-methylhistamine binding assay. The compounds tested showed affinities at hH3R with K i values ranging from 0.079 to 6.3 μM.

  9. Acute exposure to high-peak-power pulsed microwaves affecting the histamine H3 receptor expression in rat hippocampus

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In the Morris Water Maze test, high-peak-power pulsed microwave (MW)-exposed rats displayed some learning and memory behavior dysfunctions, and their escape time and swimming distance to the submerged platform were longer than those of the sham-exposed rats. To understand the molecular mechanism involved, the reverse transcription-polymerase chain reaction (RT-PCR) and the Western-blotting technique were used for investigating the mRNA and protein expression patterns of the histamine H3 receptor (H3R) in rat hippocampus. High-peak-power pulsed microwave-exposure did not remarkably lead to the change in expression of H3R mRNA in rat hippocampi;however, it promoted the up-regulatory expression of the H3R protein, which was possibly triggered through the mitogen-activated protein kinase (MAPK) pathways. Therefore, further investigation of the molecular mechanism of the MW effects on the learning and memory behaviors is required.

  10. 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...... and antagonists. We find that E2065.46 contributes most in binding H3 selective agonists (5, 6, 7) in agreement with experimental mutation studies. We also find that conserved E5.46/S5.43 in both of hH3HR and hH4HR are involved in H3/ H4 subtype selectivity. In addition, we find that M3786.55 in hH3HR provides...... additional hydrophobic interactions different from hH4HR (the corresponding amino acid of T3236.55 in hH4HR) to provide additional subtype bias. From these studies, we developed a pharmacophore model based on our predictions for known hH3HR selective antagonists in clinical study [ABT-239 1, GSK-189,254 2...

  11. Mediator-dependent Nuclear Receptor Functions

    Science.gov (United States)

    Chen, Wei; Roeder, Robert

    2011-01-01

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

  12. 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.

  13. Preliminary study of histamine H4 receptor expressed on human CD4+ T cells and its immunomodulatory potency in the IL-17 pathway of psoriasis.

    Science.gov (United States)

    Han, Song Hee; Hur, Min Seok; Kim, Min Jung; Kim, Bo Mi; Kim, Kyoung Woon; Kim, Hae Rim; Choe, Yong Beom; Ahn, Kyu Joong; Lee, Yang Won

    2017-10-01

    Previous studies have shown the expression of histamine H 4 receptor (H4R) on CD4 + T cells, especially human CD4 + T h 2-polarized T cells. This study aimed to investigate the role of H4R on these effector T cells in psoriasis. We enrolled three patients each with active psoriasis, inactive psoriasis, scalp seborrheic dermatitis, and three normal controls, and compared the basal expression of H4R mRNA in their peripheral blood CD4 + T cells. Then, we identified H4R expression in dermal CD4 + T cells. Furthermore, we investigated H4R expression after stimulating separated peripheral blood CD4 + T cells with several inflammatory cytokines. The results showed higher H4R expression in the active psoriasis group compared to the inactive psoriasis group. It was interesting that interleukin (IL)-23, which is a representative cytokine contributing to T h 17 cell differentiation, stimulated H4R expression significantly. After adding a selective H4R antagonist (JNJ-7777120) while the CD4 + T cells were polarized into T h 17 cells, we observed a tendency toward suppressed IL-17 secretion. Histamine stimulation influences the IL-17 pathway in psoriasis via the fourth histamine receptor subtype, H4R, on CD4 + T cells. The immunomodulatory roles of H4R suggest its potency as a new therapeutic target for obstinate psoriasis. Copyright © 2017 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

  14. The discovery of the benzazepine class of histamine H3 receptor antagonists.

    Science.gov (United States)

    Wilson, David M; Apps, James; Bailey, Nicholas; Bamford, Mark J; Beresford, Isabel J; Briggs, Michael A; Calver, Andrew R; Crook, Barry; Davis, Robert P; Davis, Susannah; Dean, David K; Harris, Leanne; Heightman, Tom D; Panchal, Terry; Parr, Christopher A; Quashie, Nigel; Steadman, Jon G A; Schogger, Joanne; Sehmi, Sanjeet S; Stean, Tania O; Takle, Andrew K; Trail, Brenda K; White, Trevor; Witherington, Jason; Worby, Angela; Medhurst, Andrew D

    2013-12-15

    This Letter describes the discovery of a novel series of H3 receptor antagonists. The initial medicinal chemistry strategy focused on deconstructing and simplifying an early screening hit which rapidly led to the discovery of a novel series of H3 receptor antagonists based on the benzazepine core. Employing an H3 driven pharmacodynamic model, the series was then further optimised through to a lead compound that showed robust in vivo functional activity and possessed overall excellent developability properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. 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 describe...... a fluorescence-based assay that measures NMDA receptor-mediated changes in intracellular calcium in a BHK-21 cell line stably expressing NMDA receptor NR2D with NR1 under the control of a tetracycline-inducible promoter (Tet-On). The assay selectively identifies allosteric modulators by using supramaximal...

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

    International Nuclear Information System (INIS)

    Gianlorenço, A.C.L.; Serafim, K.R.; Canto-de-Souza, A.; Mattioli, R.

    2014-01-01

    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

  17. 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.

  18. 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.

  19. Safety, tolerability and pharmacokinetics of the histamine H3 receptor antagonist, ABT-288, in healthy young adults and elderly volunteers.

    Science.gov (United States)

    Othman, Ahmed A; Haig, George; Florian, Hana; Locke, Charles; Zhang, Jun; Dutta, Sandeep

    2013-05-01

    The objective of this work was to characterize the safety, tolerability and pharmacokinetics of ABT-288, a highly selective histamine H3 receptor antagonist, in healthy young adults and elderly subjects following single and multiple dosing in a phase 1 setting. Single doses (0.1, 0.3, 1, 3, 10, 20 and 40 mg ABT-288) and multiple doses (0.5, 1.5, 3 and 6 mg ABT-288 once-daily for 14 days) were evaluated in young adults and multiple doses (0.5, 1.5, 3 and 5 mg ABT-288 once-daily for 12 days) were evaluated in elderly subjects using randomized, double-blind, placebo-controlled, dose-escalating study designs. The effect of food on ABT-288 pharmacokinetics (5 mg single dose) was evaluated using an open label, randomized, crossover design. ABT-288 safety, tolerability and pharmacokinetics were comparable in young and elderly subjects. Single doses up to 40 mg and multiple doses up to 3 mg once-daily were generally safe and well tolerated. The most frequently reported adverse events were hot flush, headache, abnormal dreams, insomnia, nausea and dizziness. ABT-288 exposure (AUC) was dose-proportional over the evaluated dose ranges. The mean elimination half-life ranged from 40 to 61 h across dose groups. Steady state was achieved by day 10 of once-daily dosing with 3.4- to 4.2-fold accumulation. Food did not have a clinically meaningful effect on ABT-288 exposure. Based on the above results, 1 and 3 mg once-daily doses of ABT-288 were advanced to phase 2 evaluation in Alzheimer's patients. © 2012 Abbott Laboratories. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

  20. Pneumonia prevention in intubated patients given sucralfate versus proton-pump inhibitors and/or histamine II receptor blockers.

    Science.gov (United States)

    Grindlinger, Gene A; Cairo, Sarah B; Duperre, Carole B

    2016-12-01

    Ventilator-associated pneumonia (VAP) is a common cause of infectious morbidity and mortality in the intensive care unit (ICU). The type of stress-ulcer prophylaxis (SUP) given to ventilated patients may, in part, be responsible. We observed an increase in VAP as ventilator bundle compliance increased and a decrease in VAP when bundle compliance decreased. We reasoned that SUP which raises gastric pH such as proton-pump inhibitors (PPIs) and histamine II (H2) receptor antagonists as opposed to SUP which does not raise pH such as sucralfate (S) may be responsible and also may alter the causative bacteria. This is a single-center retrospective cohort analysis of all intubated, adult surgical patients admitted to the surgical ICU between January and June during the 3-y period 2012-2014. Demographics, APACHE II, Injury Severity Score, VAP occurrence, culprit bacteria, ventilator days, and ICU days were recorded based on the type of SUP given. There were 45 instances of VAP in the 504 study patients, 33 in the PPI/H2 group, and 12 in the S group (P < 0.01). VAP per 1000 ventilator days were 10.2 for PPI/H2 and 3.7 for S (P < 0.01). Culprit bacteria were mostly Pseudomonas, gram-negative bacilli, and methicillin-resistant Staphylococcus aureus in PPI/H2 patients (n = 29) compared with oropharyngeal flora in S patients (n = 6; P < 0.001). There was a substantial difference in VAP occurrence and in the culprit bacteria between S and PPI/H2 treated patients due perhaps to gastric alkalization. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Cultured smooth muscle cells of the human vesical sphincter are more sensitive to histamine than are detrusor smooth muscle cells.

    Science.gov (United States)

    Neuhaus, Jochen; Oberbach, Andreas; Schwalenberg, Thilo; Stolzenburg, Jens-Uwe

    2006-05-01

    To compare histamine receptor expression in cultured smooth muscle cells from the human detrusor and internal sphincter using receptor-specific agonists. Smooth muscle cells from the bladder dome and internal sphincter were cultured from 5 male patients undergoing cystectomy for bladder cancer therapy. Calcium transients in cells stimulated with carbachol, histamine, histamine receptor 1 (H1R)-specific heptanecarboxamide (HTMT), dimaprit (H2R), and R-(alpha)-methylhistamine (H3R) were measured by calcium imaging. Histamine receptor proteins were detected by Western blot analysis and immunocytochemistry. H1R, H2R, and H3R expression was found in tissue and cultured cells. Carbachol stimulated equal numbers of detrusor and sphincter cells (60% and 51%, respectively). Histamine stimulated significantly more cells than carbachol in detrusor (100%) and sphincter (99.34%) cells. Calcium responses to carbachol in detrusor and sphincter cells were comparable and did not differ from those to histamine in detrusor cells. However, histamine and specific agonists stimulated more sphincter cells than did carbachol (P <0.001), and the calcium increase was greater in sphincter cells than in detrusor cells. Single cell analysis revealed comparable H2R responses in detrusor and sphincter cells, but H1R and H3R-mediated calcium reactions were significantly greater in sphincter cells. Histamine very effectively induces calcium release in smooth muscle cells. In sphincter cells, histamine is even more effective than carbachol regarding the number of reacting cells and the intracellular calcium increase. Some of the variability in the outcome of antihistaminic interstitial cystitis therapies might be caused by the ineffectiveness of the chosen antihistaminic or unintentional weakening of sphincteric function.

  2. Histamine and Antihistamines / Histamin i antihistamini

    Directory of Open Access Journals (Sweden)

    Stojković Nikola

    2015-03-01

    Full Text Available Poslednjih godina beleži se kontinuirani rast prevalencije alergijskih oboljenja. Alergijski imunski odgovor predstavlja jednu kompleksnu mrežu ćelijskih događaja u kojoj učestvuju mnogobrojne imunske ćelije i medijatori. On predstavlja interakciju urođenog i stečenog imunskog odgovora. Ključnu ulogu u imunološkoj kaskadi zauzima histamin, prirodni sastojak tela, koga u alergijskom inflamatornom odgovoru oslobađaju mastociti i bazofili. Cilj ovog rada bio je naglasiti ulogu histamina u alergijskim imunološkim događajima, njegov efekat na Th1 i Th2 subpopulaciju limfocita i produkciju odgovarajućih citokina, kao i ulogu blokatora histamina u tretmanu ovih stanja. Histamin ostvaruje svoj efekat vezivanjem za četiri tipa svojih receptora koji su široko distribuirani u organizmu. Blokatori histamina blokiraju mnogobrojne efekte histamina vezivanjem za ove receptore. Cetirizin, visoko selektivni antihistaminik druge generacije, ne ostvaruje svoje efekte samo vezivanjem za H1 receptore već dovodi do atenuisanja mnogobrojnih zbivanja tokom inflamacijskog procesa. Dobro poznavanje efekata histaminskih blokatora, među njima i cetirizina, može dovesti do pravog odabira terapije u tretmanu alergijskih oboljenja.

  3. Sedation and memory: studies with a histamine H-1 receptor antagonist.

    Science.gov (United States)

    Turner, Claire; Handford, Alison D F; Nicholson, Anthony N

    2006-07-01

    The influence of sedation on the effect of an H-1 receptor antagonist on various cognitive functions, including memory, were evaluated. Diphenhydramine (50, 75 and 100 mg) and lorazepam (0.5 and 1.5 mg) were given on single occasions to 12 healthy volunteers (six males, six females) aged 20-33 (mean 23.4) years. Subjective assessments of sedation, sleep latencies, digit symbol substitution, choice reaction time, sustained attention and memory recall were studied 1.0 h before and 0.5, 2.0 and 3.5 h after drug ingestion. The study was double blind, placebo controlled and with a crossover design. With all doses of diphenhydramine there was subjective sedation, reduced sleep latencies and impairments in performance on the digit symbol substitution, choice reaction time and sustained attention tasks. No effects were observed with 0.5 mg lorazepam. With 1.5 mg lorazepam there was subjective sedation, fewer digit symbol substitutions, slowed choice reaction time, impaired attention and memory, but no effect on sleep latencies. Contrast analysis of data measured at all time points showed that although there was no difference in the effect of diphenhydramine (100 mg) and lorazepam (1.5 mg) on those tasks without a memory component, response times were slower with lorazepam on those tasks with a memory component. However, both 100 mg diphenhydramine and 1.5 mg lorazepam impaired prompted recall measured at 2 h post-ingestion only. It is considered that impaired memory is not necessarily associated with sedation, and that impairment of memory with drugs that lead to sedation may be effected through neuronal systems independent of those that affect arousal.

  4. Regional differential effects of the novel histamine H3 receptor antagonist 6-[(3-cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide hydrochloride (GSK189254) on histamine release in the central nervous system of freely moving rats.

    Science.gov (United States)

    Giannoni, Patrizia; Medhurst, Andrew D; Passani, Maria Beatrice; Giovannini, Maria Grazia; Ballini, Chiara; Corte, Laura Della; Blandina, Patrizio

    2010-01-01

    After oral administration, the nonimidazole histamine H(3) receptor antagonist, 6-[(3-cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide hydrochloride (GSK189254), increased histamine release from the tuberomammillary nucleus, where all histaminergic somata are localized, and from where their axons project to the entire brain. To further understand functional histaminergic circuitry in the brain, dual-probe microdialysis was used to pharmacologically block H(3) receptors in the tuberomammillary nucleus, and monitor histamine release in projection areas. Perfusion of the tuberomammillary nucleus with GSK189254 increased histamine release from the tuberomammillary nucleus, nucleus basalis magnocellularis, and cortex, but not from the striatum or nucleus accumbens. Cortical acetylcholine (ACh) release was also increased, but striatal dopamine release was not affected. When administered locally, GSK189254 increased histamine release from the nucleus basalis magnocellularis, but not from the striatum. Thus, defined by their sensitivity to GSK189254, histaminergic neurons establish distinct pathways according to their terminal projections, and can differentially modulate neurotransmitter release in a brain region-specific manner. Consistent with its effects on cortical ACh release, systemic administration of GSK189254 antagonized the amnesic effects of scopolamine in the rat object recognition test, a cognition paradigm with important cortical components.

  5. 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.

  6. [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.

  7. The extracellular loop 2 (ECL2 of the human histamine H4 receptor substantially contributes to ligand binding and constitutive activity.

    Directory of Open Access Journals (Sweden)

    David Wifling

    Full Text Available In contrast to the corresponding mouse and rat orthologs, the human histamine H4 receptor (hH4R shows extraordinarily high constitutive activity. In the extracellular loop (ECL, replacement of F169 by V as in the mouse H4R significantly reduced constitutive activity. Stabilization of the inactive state was even more pronounced for a double mutant, in which, in addition to F169V, S179 in the ligand binding site was replaced by M. To study the role of the FF motif in ECL2, we generated the hH4R-F168A mutant. The receptor was co-expressed in Sf9 insect cells with the G-protein subunits Gαi2 and Gβ1γ2, and the membranes were studied in [3H]histamine binding and functional [35S]GTPγS assays. The potency of various ligands at the hH4R-F168A mutant decreased compared to the wild-type hH4R, for example by 30- and more than 100-fold in case of the H4R agonist UR-PI376 and histamine, respectively. The high constitutive activity of the hH4R was completely lost in the hH4R-F168A mutant, as reflected by neutral antagonism of thioperamide, a full inverse agonist at the wild-type hH4R. By analogy, JNJ7777120 was a partial inverse agonist at the hH4R, but a partial agonist at the hH4R-F168A mutant, again demonstrating the decrease in constitutive activity due to F168A mutation. Thus, F168 was proven to play a key role not only in ligand binding and potency, but also in the high constitutive activity of the hH4R.

  8. 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 histamine 2 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

  9. 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.

  10. Histamine H3 receptor activation selectively inhibits dopamine D1 receptor-dependent [3H]GABA release from depolarization-stimulated slices of rat substantia nigra pars reticulata

    International Nuclear Information System (INIS)

    Aceves, J.; Young, J.M.; Arias-Montano, J.A.; Floran, B.; Garcia, M.

    1997-01-01

    The release of [ 3 H]GABA from slices of rat substantia nigra pars reticulata induced by increasing extracellular K + from 6 to 15 mM in the presence of 10 μM sulpiride was inhibited by 73±3% by 1 μM SCH 23390, consistent with a large component of release dependent upon D 1 receptor activation. The histamine H 3 receptor-selective agonist immepip (1 μM) and the non-selective agonist histamine (100 μM) inhibited [ 3 H]GABA release by 78±2 and 80±2%, respectively. The inhibition by both agonists was reversed by the H 3 receptor antagonist thioperamide (1 μM). However, in the presence of 1 μM SCH 23390 depolarization-induced release of [ 3 H]GABA was not significantly decreased by 1 μM immepip. In rats depleted of dopamine by pretreatment with reserpine, immepip no longer inhibited control release of [ 3 H]GABA, but in the presence of 1 μM SKF 38393, which produced a 7±1-fold stimulation of release, immepip reduced the release to a level not statistically different from that in the presence of immepip alone. Immepip (1 μM) also inhibited the depolarization-induced release of [ 3 H]dopamine from substantia nigra pars reticulata slices, by 38±3%.The evidence is consistent with the proposition that activation of histamine H 3 receptors leads to the selective inhibition of the component of depolarization-induced [ 3 H]GABA release in substantia nigra pars reticulata slices which is dependent upon D 1 receptor activation. This appears to be largely an action at the terminals of the striatonigral GABA projection neurons, which may be enhanced by a partial inhibition of dendritic [ 3 H]dopamine release. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  11. Generation of cell lines for drug discovery through random activation of gene expression: application to the human histamine H3 receptor.

    Science.gov (United States)

    Song, J; Doucette, C; Hanniford, D; Hunady, K; Wang, N; Sherf, B; Harrington, J J; Brunden, K R; Stricker-Krongrad, A

    2005-06-01

    Target-based high-throughput screening (HTS) plays an integral role in drug discovery. The implementation of HTS assays generally requires high expression levels of the target protein, and this is typically accomplished using recombinant cDNA methodologies. However, the isolated gene sequences to many drug targets have intellectual property claims that restrict the ability to implement drug discovery programs. The present study describes the pharmacological characterization of the human histamine H3 receptor that was expressed using random activation of gene expression (RAGE), a technology that over-expresses proteins by up-regulating endogenous genes rather than introducing cDNA expression vectors into the cell. Saturation binding analysis using [125I]iodoproxyfan and RAGE-H3 membranes revealed a single class of binding sites with a K(D) value of 0.77 nM and a B(max) equal to 756 fmol/mg of protein. Competition binding studies showed that the rank order of potency for H3 agonists was N(alpha)-methylhistamine approximately (R)-alpha- methylhistamine > histamine and that the rank order of potency for H3 antagonists was clobenpropit > iodophenpropit > thioperamide. The same rank order of potency for H3 agonists and antagonists was observed in the functional assays as in the binding assays. The Fluorometic Imaging Plate Reader assays in RAGE-H3 cells gave high Z' values for agonist and antagonist screening, respectively. These results reveal that the human H3 receptor expressed with the RAGE technology is pharmacologically comparable to that expressed through recombinant methods. Moreover, the level of expression of the H3 receptor in the RAGE-H3 cells is suitable for HTS and secondary assays.

  12. Induction of the Histamine-Forming Enzyme Histidine Decarboxylase in Skeletal Muscles by Prolonged Muscular Work: Histological Demonstration and Mediation by Cytokines.

    Science.gov (United States)

    Ayada, Kentaro; Tsuchiya, Masahiro; Yoneda, Hiroyuki; Yamaguchi, Kouji; Kumamoto, Hiroyuki; Sasaki, Keiichi; Tadano, Takeshi; Watanabe, Makoto; Endo, Yasuo

    2017-01-01

    Recent studies suggest that histamine-a regulator of the microcirculation-may play important roles in exercise. We have shown that the histamine-forming enzyme histidine decarboxylase (HDC) is induced in skeletal muscles by prolonged muscular work (PMW). However, histological analysis of such HDC induction is lacking due to appropriate anti-HDC antibodies being unavailable. We also showed that the inflammatory cytokines interleukin (IL)-1 and tumor necrosis factor (TNF)-α can induce HDC, and that PMW increases both IL-1α and IL-1β in skeletal muscles. Here, we examined the effects (a) of PMW on the histological evidence of HDC induction and (b) of IL-1β and TNF-α on HDC activity in skeletal muscles. By immunostaining using a recently introduced commercial polyclonal anti-HDC antibody, we found that cells in the endomysium and around blood vessels, and also some muscle fibers themselves, became HDC-positive after PMW. After PMW, TNF-α, but not IL-1α or IL-1β, was detected in the blood serum. The minimum intravenous dose of IL-1β that would induce HDC activity was about 1/10 that of TNF-α, while in combination they synergistically augmented HDC activity. These results suggest that PMW induces HDC in skeletal muscles, including cells in the endomysium and around blood vessels, and also some muscle fibers themselves, and that IL-1β and TNF-α may cooperatively mediate this induction.

  13. A mixture of anatase and rutile TiO2 nanoparticles induces histamine secretion in mast cells

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    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.

  14. Ciproxifan, a histamine H{sub 3} receptor antagonist and inverse agonist, presynaptically inhibits glutamate release in rat hippocampus

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Cheng-Wei; Lin, Tzu-Yu [Department of Anesthesiology, Far-Eastern Memorial Hospital, Pan-Chiao District, New Taipei City 22060, Taiwan (China); Department of Mechanical Engineering, Yuan Ze University, Taoyuan 320, Taiwan (China); Chang, Chia-Ying [Department of Anesthesiology, Far-Eastern Memorial Hospital, Pan-Chiao District, New Taipei City 22060, Taiwan (China); Department of Chemistry, Fu Jen Catholic University, No. 510, Chung-Cheng Road, Hsin-Chuang District, New Taipei City 24205, Taiwan (China); Huang, Shu-Kuei [Department of Anesthesiology, Far-Eastern Memorial Hospital, Pan-Chiao District, New Taipei City 22060, Taiwan (China); Wang, Su-Jane, E-mail: med0003@mail.fju.edu.tw [School of Medicine, Fu Jen Catholic University, No. 510, Chung-Cheng Rd., Hsin-Chuang, New Taipei 24205, Taiwan (China); Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan City, Taiwan (China)

    2017-03-15

    Ciproxifan is an H{sub 3} receptor antagonist and inverse agonist with antipsychotic effects in several preclinical models; its effect on glutamate release has been investigated in the rat hippocampus. In a synaptosomal preparation, ciproxifan reduced 4-aminopyridine (4-AP)-evoked Ca{sup 2+}-dependent glutamate release and cytosolic Ca{sup 2+} concentration elevation but did not affect the membrane potential. The inhibitory effect of ciproxifan on 4-AP-evoked glutamate release was prevented by the Gi/Go-protein inhibitor pertussis toxin and Ca{sub v}2.2 (N-type) and Ca{sub v}2.1 (P/Q-type) channel blocker ω-conotoxin MVIIC, but was not affected by the intracellular Ca{sup 2+}-release inhibitors dantrolene and CGP37157. Furthermore, the phospholipase A{sub 2} (PLA{sub 2}) inhibitor OBAA, prostaglandin E{sub 2} (PGE{sub 2}), PGE2 subtype 2 (EP{sub 2}) receptor antagonist PF04418948, and extracellular signal-regulated kinase (ERK) inhibitor FR180204 eliminated the inhibitory effect of ciproxifan on glutamate release. Ciproxifan reduced the 4-AP-evoked phosphorylation of ERK and synapsin I, a presynaptic target of ERK. The ciproxifan-mediated inhibition of glutamate release was prevented in synaptosomes from synapsin I-deficient mice. Moreover, ciproxifan reduced the frequency of miniature excitatory postsynaptic currents without affecting their amplitude in hippocampal slices. Our data suggest that ciproxifan, acting through the blockade of Gi/Go protein-coupled H{sub 3} receptors present on hippocampal nerve terminals, reduces voltage-dependent Ca{sup 2+} entry by diminishing PLA{sub 2}/PGE{sub 2}/EP{sub 2} receptor pathway, which subsequently suppresses the ERK/synapsin I cascade to decrease the evoked glutamate release. - Highlights: • Ciproxifan presynaptically reduces glutamate release in the hippocampus in vitro. • Decrease in voltage-dependent Ca{sup 2+} influx is involved. • A role for the PLA{sub 2}/PGE{sub 2}/EP{sub 2} pathway in the action of

  15. The novel non-imidazole histamine H3 receptor antagonist DL77 reduces voluntary alcohol intake and ethanol-induced conditioned place preference in mice.

    Science.gov (United States)

    Bahi, Amine; Sadek, Bassem; Nurulain, Syed M; Łażewska, Dorota; Kieć-Kononowicz, Katarzyna

    2015-11-01

    It has become clear that histamine H3 receptors (H3R) have been implicated in modulating ethanol intake and preference in laboratory animals. The novel non-imidazole H3R antagonist DL77 with excellent selectivity profile shows high in-vivo potency as well as in-vitro antagonist affinity with ED50 of 2.1 ± 0.2 mg/kg and pKi=8.08, respectively. In the present study, and applying an unlimited access two-bottle choice procedure, the anti-alcohol effects of the H3R antagonist, DL77 (0, 3, 10 and 30 mg/kg; i.p.), were investigated in adult mice. In this C57BL/6 line, effects of DL77 on voluntary alcohol intake and preference, as well as on total fluid intake were evaluated. Results have shown that DL77, dose-dependently, reduced both ethanol intake and preference. These effects were very selective as both saccharin and quinine, used to control for taste sensitivity, and intakes were not affected following DL77 pre-application. More importantly, systemic administration of DL77 (10 mg/kg) during acquisition inhibited ethanol-induced conditioned-place preference (EtOH-CPP) as measured using an unbiased protocol. The anti-alcohol activity observed for DL77 was abrogated when mice were pretreated with the selective H3R agonist R-(α)-methyl-histamine (RAMH) (10 mg/kg), or with the CNS penetrant H1R antagonist pyrilamine (PYR) (10mg/kg). These results suggest that DL77 has a predominant role in two in vivo effects of ethanol. Therefore, signaling via H3R is essential for ethanol-related consumption and conditioned reward and may represent a novel therapeutic pharmacological target to tackle ethanol abuse and alcoholism. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Hybrid approach to structure modeling of the histamine H3 receptor: Multi-level assessment as a tool for model verification.

    Directory of Open Access Journals (Sweden)

    Jakub Jończyk

    Full Text Available The crucial role of G-protein coupled receptors and the significant achievements associated with a better understanding of the spatial structure of known receptors in this family encouraged us to undertake a study on the histamine H3 receptor, whose crystal structure is still unresolved. The latest literature data and availability of different software enabled us to build homology models of higher accuracy than previously published ones. The new models are expected to be closer to crystal structures; and therefore, they are much more helpful in the design of potential ligands. In this article, we describe the generation of homology models with the use of diverse tools and a hybrid assessment. Our study incorporates a hybrid assessment connecting knowledge-based scoring algorithms with a two-step ligand-based docking procedure. Knowledge-based scoring employs probability theory for global energy minimum determination based on information about native amino acid conformation from a dataset of experimentally determined protein structures. For a two-step docking procedure two programs were applied: GOLD was used in the first step and Glide in the second. Hybrid approaches offer advantages by combining various theoretical methods in one modeling algorithm. The biggest advantage of hybrid methods is their intrinsic ability to self-update and self-refine when additional structural data are acquired. Moreover, the diversity of computational methods and structural data used in hybrid approaches for structure prediction limit inaccuracies resulting from theoretical approximations or fuzziness of experimental data. The results of docking to the new H3 receptor model allowed us to analyze ligand-receptor interactions for reference compounds.

  17. Involvement of prostaglandins and histamine in radiation-induced temperature responses in rats

    International Nuclear Information System (INIS)

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

    1990-01-01

    Exposure of rats to 1-15 Gy of gamma radiation induced hyperthermia, whereas exposure to 20-150 Gy produced hypothermia. Since radiation exposure induced the release of prostaglandins (PGs) and histamine, the role of PGs and histamine in radiation-induced temperature changes was examined. Radiation-induced hyper- and hypothermia were antagonized by pretreatment with indomethacin, a cyclooxygenase inhibitor. Intracerebroventricular administration of PGE2 and PGD2 induced hyper- and hypothermia, respectively. Administration of SC-19220, a specific PGE2 antagonist, attenuated PGE2- and radiation-induced hyperthermia, but it did not antagonize PGD2- or radiation-induced hypothermia. Consistent with an apparent role of histamine in hypothermia, administration of disodium cromoglycate (a mast cell stabilizer), mepyramine (H1-receptor antagonist), or cimetidine (H2-receptor antagonist) attenuated PGD2- and radiation-induced hypothermia. These results suggest that radiation-induced hyperthermia is mediated via PGE2 and that radiation-induced hypothermia is mediated by another PG, possibly PGD2, via histamine

  18. 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

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    Hiroyuki Mizuguchi

    2016-04-01

    Full Text Available 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.

  19. 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 (H 1 , H 2 , and H 3 ). 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 EC 50 of 1.3 µM, but failed to significantly alter sIPSC amplitude. HA-induced increases in sIPSC frequency were sensitive to tetrodotoxin (TTX), required extracellular Ca 2+ , 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 H 1 and H 2 receptors were involved in HA-induced increases in sIPSCs and interneuron excitability. Immunohistochemical staining showed that both H 1 and H 2 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.

  20. Histamine type I (H1) receptor radioligand binding studies on normal T cell subsets, B cells, and monocytes

    International Nuclear Information System (INIS)

    Cameron, W.; Doyle, K.; Rocklin, R.E.

    1986-01-01

    A single, specific binding site for [ 3 H]pyrilamine on normal human T helper, T suppressor, B cells, and monocytes was documented. The binding of the radioligand to its receptor is reversible with cold H 1 antagonist, saturates at 40 to 60 nM, and binding equilibrium is achieved in 2 to 4 min. Using a computer program (Ligand), the authors calculated the dissociation constants, binding capacities, and numbers of receptors per cell for each of the different cell types. Monocytes were found to have the highest affinity for [ 3 H]pyrilamine, followed by T helper cells, B cells and T suppressor cells (K/sub D/ = 44.6 +/- 49.4 nM). T suppressor cells were found to express the higher number of H 1 receptors per cell followed by B cells, T helper cells, and monocytes. The binding affinity for [ 3 H]pyrilamine increased over a 48-hr period, whereas the number of receptors per T cell was essentially unchanged. In contrast, T cells stimulated with Con A or PHA were shown to have a greater than fourfold increase in the number of receptors per cell, whereas the binding affinity for [ 3 H]pyrilamine decreased over the 48-hr period. Although the function of H 1 receptors on T cells, B cells, and monocytes has not been completely defined, this receptor has the potential of playing an important role in the modulating the immune response

  1. Inositol trisphosphate receptor mediated spatiotemporal calcium signalling.

    Science.gov (United States)

    Miyazaki, S

    1995-04-01

    Spatiotemporal Ca2+ signalling in the cytoplasm is currently understood as an excitation phenomenon by analogy with electrical excitation in the plasma membrane. In many cell types, Ca2+ waves and Ca2+ oscillations are mediated by inositol 1,4,5-trisphosphate (IP3) receptor/Ca2+ channels in the endoplasmic reticulum membrane, with positive feedback between cytosolic Ca2+ and IP3-induced Ca2+ release creating a regenerative process. Remarkable advances have been made in the past year in the analysis of subcellular Ca2+ microdomains using confocal microscopy and of Ca2+ influx pathways that are functionally coupled to IP3-induced Ca2+ release. Ca2+ signals can be conveyed into the nucleus and mitochondria. Ca2+ entry from outside the cell allows repetitive Ca2+ release by providing Ca2+ to refill the endoplasmic reticulum stores, thus giving rise to frequency-encoded Ca2+ signals.

  2. Effect of FRG-8813, a new-type histamine H(2)-receptor antagonist, on the recurrence of gastric ulcer after healing by drug treatment in rats.

    Science.gov (United States)

    Ajioka, H; Miyake, H; Matsuura, N

    2000-08-01

    We investigated the recurrence of ulcers in rats after treatment with FRG-8813, (+/-)-2-(furfurylsulfinyl)-N-[4- [4-(piperidinomethyl)-2-pyridyl] oxy-(Z)-2-butenyl] acetamide, a novel histamine H(2)-receptor antagonist. Chronic gastric ulcers were induced by serosa-searing with a hot metal bar, and the ulcer healing and recurrence after treatment with FRG-8813 or famotidine were evaluated by endoscopy for 160 days. At the dose of 30 mg/kg p. o., once daily, the treatment with FRG-8813 or famotidine for 60 days, which was stopped earlier if the ulcer had healed, accelerated the ulcer healing significantly. A subsequent follow-up study on the healed rats showed that the cumulative recurrence rate of rats healed by FRG-8813 was lower than that of naturally healed rats or rats healed by famotidine. In many cases of rats healed by FRG-8813, the regenerated mucosa was normal in contrast with the control of famotidine-healed animals. The mucosal regeneration index of the gastric ulcer after 10 days' administration of FRG-8813 was significantly higher than that obtained with famotidine. After cessation of the treatment with famotidine for 7 days, rebound hyperacidity was induced; but such rebound did not occur with FRG-8813. Considering the low recurrence rate of ulcers after FRG-8813 treatment, we suggest that FRG-8813 treatment may provide additional benefits in peptic ulcer therapy. Copyright 2000 S. Karger AG, Basel

  3. 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.

  4. The vascular permeabilizing factors histamine and serotonin induce angiogenesis through TR3/Nur77 and subsequently truncate it through thrombospondin-1

    Science.gov (United States)

    Qin, Liuliang; Zhao, Dezheng; Xu, Jianfeng; Ren, Xianghui; Terwilliger, Ernest F.; Parangi, Sareh; Lawler, Jack; Dvorak, Harold F.

    2013-01-01

    Angiogenesis plays an important role in cancer and in many other human diseases. Vascular endothelial growth factor-A (VEGF-A), the best known angiogenic factor, was originally discovered as a potent vascular permeability factor (VPF), suggesting that other vascular permeabilizing agents, such as histamine and serotonin, might also have angiogenic activity. We recently demonstrated that, like VEGF-A, histamine and serotonin up-regulate the orphan nuclear receptor and transcription factor TR3 (mouse homolog Nur77) and that TR3/Nur77 is essential for their vascular permeabilizing activities. We now report that histamine and serotonin are also angiogenic factors that, at low micromolar concentrations, induce endothelial cell proliferation, migration and tube formation in vitro, and angiogenesis in vivo. All of these responses are mediated through specific histamine and serotonin receptors, are independent of VEGF-A, and are directly dependent on TR3/Nur77. Initially, the angiogenic response closely resembled that induced by VEGF-A, with generation of “mother” vessels. However, after ∼10 days, mother vessels began to regress as histamine and serotonin, unlike VEGF-A, up-regulated the potent angiogenesis inhibitor thrombospondin-1, thereby triggering a negative feedback loop. Thus, histamine and serotonin induce an angiogenic response that fits the time scale of acute inflammation. PMID:23315169

  5. 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 (H 1 ) 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 H 1 receptor, the similar studies on non-human pet H 1 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 H 1 receptors were built based on the crystal structure of human H 1 receptor bound to antagonist doxepin (PDB 3RZE) and fexofenadine was subsequently docked to human, dog and cat H 1 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 H 1 related allergic conditions of dog and cat. Nonetheless, subtle systemic differences among human, dog and cat H 1 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

  6. Effects of central histamine receptors blockade on GABA(A) agonist-induced food intake in broiler cockerels.

    Science.gov (United States)

    Morteza, Zendehdel; Vahhab, Babapour; Hossein, Jonaidi

    2008-02-01

    In this study, the effect of intracerebroventricular (i.c.v) injection of H1, H2 and H3 antagonists on feed intake induced by GABA(A) agonist was evaluated. In Experiment 1, the animals received chloropheniramine, a H1 antagonist and then muscimol, a GABA(A) agonist. In Experiment 2, chickens received famotidine, a H2 receptor antagonist, prior to injection of muscimol. Finally in Experiment 3, the birds were injected with thioperamide, a H3 receptor antagonist and muscimol. Cumulative food intake was measured 15, 30, 45, 60, 90, 120, 150 and 180 min after injections. The results of this study indicated that effects of muscimol on food intake inhibited by pretreatment with chloropheneramine maleate (p GABA(A) receptor interaction on food intake in broiler cockerels.

  7. 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....

  8. Histamine fish poisoning revisited.

    Science.gov (United States)

    Lehane, L; Olley, J

    2000-06-30

    Histamine (or scombroid) fish poisoning (HFP) is reviewed in a risk-assessment framework in an attempt to arrive at an informed characterisation of risk. Histamine is the main toxin involved in HFP, but the disease is not uncomplicated histamine poisoning. Although it is generally associated with high levels of histamine (> or =50 mg/100 g) in bacterially contaminated fish of particular species, the pathogenesis of HFP has not been clearly elucidated. Various hypotheses have been put forward to explain why histamine consumed in spoiled fish is more toxic than pure histamine taken orally, but none has proved totally satisfactory. Urocanic acid, like histamine, an imidazole compound derived from histidine in spoiling fish, may be the "missing factor" in HFP. cis-Urocanic acid has recently been recognised as a mast cell degranulator, and endogenous histamine from mast cell degranulation may augment the exogenous histamine consumed in spoiled fish. HFP is a mild disease, but is important in relation to food safety and international trade. Consumers are becoming more demanding, and litigation following food poisoning incidents is becoming more common. Producers, distributors and restaurants are increasingly held liable for the quality of the products they handle and sell. Many countries have set guidelines for maximum permitted levels of histamine in fish. However, histamine concentrations within a spoiled fish are extremely variable, as is the threshold toxic dose. Until the identity, levels and potency of possible potentiators and/or mast-cell-degranulating factors are elucidated, it is difficult to establish regulatory limits for histamine in foods on the basis of potential health hazard. Histidine decarboxylating bacteria produce histamine from free histidine in spoiling fish. Although some are present in the normal microbial flora of live fish, most seem to be derived from post-catching contamination on board fishing vessels, at the processing plant or in the

  9. Histamine, carbachol, and serotonin induce hyperresponsiveness to ATP in guinea pig tracheas: involvement of COX-2 pathway.

    Science.gov (United States)

    Montaño, Luis M; Carbajal, Verónica; Vargas, Mario H; García-Hernández, Luz M; Díaz-Hernández, Verónica; Checa, Marco; Barajas-López, Carlos

    2013-08-01

    Extracellular ATP promotes an indirect contraction of airway smooth muscle via the secondary release of thromboxane A2 (TXA2) from airway epithelium. Our aim was to evaluate if common contractile agonists modify this response to ATP. Tracheas from sensitized guinea pigs were used to evaluate ATP-induced contractions before and after a transient contraction produced by histamine, carbachol, or serotonin. Epithelial mRNA for COX-1 and COX-2 was measured by RT-PCR and their expression assessed by immunohistochemistry. Compared with the initial response, ATP-induced contraction was potentiated by pretreatment with histamine, carbachol, or serotonin. Either suramin (antagonist of P2X and P2Y receptors) plus RB2 (antagonist of P2Y receptors) or indomethacin (inhibitor of COX-1 and COX-2) annulled the ATP-induced contraction, suggesting that it was mediated by P2Y receptor stimulation and TXA2 production. When COX-2 was inhibited by SC-58125 or thromboxane receptors were antagonized by SQ-29548, just the potentiation was abolished, leaving the basal response intact. Airway epithelial cells showed increased COX-2 mRNA after stimulation with histamine or carbachol, but not serotonin, while COX-1 mRNA was unaffected. Immunochemistry corroborated this upregulation of COX-2. In conclusion, we showed for the first time that histamine and carbachol cause hyperresponsiveness to ATP by upregulating COX-2 in airway epithelium, which likely increases TXA2 production. Serotonin-mediated hyperresponsiveness seems to be independent of COX-2 upregulation, but nonetheless is TXA2 dependent. Because acetylcholine, histamine, and serotonin can be present during asthmatic exacerbations, their potential interactions with ATP might be relevant in its pathophysiology.

  10. Endothelial Regulator of Calcineurin 1 Promotes Barrier Integrity and Modulates Histamine-Induced Barrier Dysfunction in Anaphylaxis

    Directory of Open Access Journals (Sweden)

    Constanza Ballesteros-Martinez

    2017-10-01

    Full Text Available Anaphylaxis, the most serious and life-threatening allergic reaction, produces the release of inflammatory mediators by mast cells and basophils. Regulator of calcineurin 1 (Rcan1 is a negative regulator of mast-cell degranulation. The action of mediators leads to vasodilation and an increase in vascular permeability, causing great loss of intravascular volume in a short time. Nevertheless, the molecular basis remains unexplored on the vascular level. We investigated Rcan1 expression induced by histamine, platelet-activating factor (PAF, and epinephrine in primary human vein (HV-/artery (HA-derived endothelial cells (ECs and human dermal microvascular ECs (HMVEC-D. Vascular permeability was analyzed in vitro in human ECs with forced Rcan1 expression using Transwell migration assays and in vivo using Rcan1 knockout mice. Histamine, but neither PAF nor epinephrine, induced Rcan1-4 mRNA and protein expression in primary HV-ECs, HA-ECs, and HMVEC-D through histamine receptor 1 (H1R. These effects were prevented by pharmacological inhibition of calcineurin with cyclosporine A. Moreover, intravenous histamine administration increased Rcan1 expression in lung tissues of mice undergoing experimental anaphylaxis. Functional in vitro assays showed that overexpression of Rcan1 promotes barrier integrity, suggesting a role played by this molecule in vascular permeability. Consistent with these findings, in vivo models of subcutaneous and intravenous histamine-mediated fluid extravasation showed increased response in skin, aorta, and lungs of Rcan1-deficient mice compared with wild-type animals. These findings reveal that endothelial Rcan1 is synthesized in response to histamine through a calcineurin-sensitive pathway and may reduce barrier breakdown, thus contributing to the strengthening of the endothelium and resistance to anaphylaxis. These new insights underscore its potential role as a regulator of sensitivity to anaphylaxis in humans.

  11. Histamine Enhances Theta-Coupled Spiking and Gamma Oscillations in the Medial Entorhinal Cortex Consistent With Successful Spatial Recognition.

    Science.gov (United States)

    Chen, Quanhui; Luo, Fenlan; Yue, Faguo; Xia, Jianxia; Xiao, Qin; Liao, Xiang; Jiang, Jun; Zhang, Jun; Hu, Bo; Gao, Dong; He, Chao; Hu, Zhian

    2017-06-07

    Encoding of spatial information in the superficial layers of the medial entorhinal cortex (sMEC) involves theta-modulated spiking and gamma oscillations, as well as spatially tuned grid cells and border cells. Little is known about the role of the arousal-promoting histaminergic system in the modification of information encoded in the sMEC in vivo, and how such histamine-regulated information correlates with behavioral functions. Here, we show that histamine upregulates the neural excitability of a significant proportion of neurons (16.32%, 39.18%, and 52.94% at 30 μM, 300 μM, and 3 mM, respectively) and increases local theta (4-12 Hz) and gamma power (low: 25-48 Hz; high: 60-120 Hz) in the sMEC, through activation of histamine receptor types 1 and 3. During spatial exploration, the strength of theta-modulated firing of putative principal neurons and high gamma oscillations is enhanced about 2-fold by histamine. The histamine-mediated increase of theta phase-locking of spikes and high gamma power is consistent with successful spatial recognition. These results, for the first time, reveal possible mechanisms involving the arousal-promoting histaminergic system in the modulation of spatial cognition. Published by Oxford University Press 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  12. Histamine ameliorates spatial memory deficits induced by MK-801 infusion into ventral hippocampus as evaluated by radial maze task in rats

    Institute of Scientific and Technical Information of China (English)

    Li-sha XU; Li-xia YANG; Wei-wei HU; Xiao YU; Li MA; Lu-ying LIU; Er-qing WEI; Zhong CHEN

    2005-01-01

    Aim: To investigate the role of histamine in memory deficits induced by MK-801 infusion into the ventral hippocampus in rats. Methods: An 8-arm radial maze (4arms baited) was used to assess spatial memory. Results: Bilateral ventral intrahippocampal (ih) infusion of MK-801 (0.3 μg/site), an N-methyl-D-aspartate (NMDA) antagonist, impaired the retrieval process in both working memory and reference memory. Intrahippocampal injection of histamine (25 or 50 ng/site) or intraperitoneal (ip) injection of histidine (25, 50 or 100 mg/kg) markedly ameliorated the spatial memory deficits induced by MK-801. Both the histamine H1 antagonist pyrilamine (0.5 or 1.0 μg/site, ih) and the H2 antagonist cimetidine (2.5 μg/site,ih) abolished the ameliorating effect of histidine (100 mg/kg, ip) on reference memory deficits, but not that on working memory deficits induced by MK-801. Conclusion:The results indicate that histamine in the ventral hippocampus can ameliorate MK-801-induced spatial memory deficits, and that histamine's effect on reference memory is mediated by postsynaptic histamine H1 and H2 receptors.

  13. Immunoregulatory T cells in man. Histamine-induced suppressor T cells are derived from a Leu 2+ (T8+) subpopulation distinct from that which gives rise to cytotoxic T cells

    International Nuclear Information System (INIS)

    Sansoni, P.; Silverman, E.D.; Khan, M.M.; Melmon, K.L.; Engleman, E.G.

    1985-01-01

    One mechanism of histamine-mediated inhibition of the immune response in man is to activate T suppressor cells that bear the Leu 2 (OKT8) marker. The current study was undertaken to characterize the histamine-induced suppressor cell using a monoclonal antibody (9.3) shown previously to distinguish cytotoxic T cells from antigen-specific suppressor T cells. Leu 2+ cells isolated from peripheral blood were further separated with antibody 9.3 into Leu 2+, 9.3+, and Leu 2+, 9.3- subsets and each subset was incubated with different concentrations of histamine before determining their ability to suppress immune responses in vitro. The results indicate that the Leu 2+, 9.3- subpopulation includes all histamine-induced suppressor cells, that 10(-4) M histamine is the optimal concentration for suppressor cell induction, and that exposure of Leu 2+, 9.3- cells to histamine for 30 s is sufficient to initiate the induction process. After treatment with histamine these cells inhibit both phytohemagglutinin-induced T cell proliferation and pokeweed mitogen-induced B cell differentiation. The suppression of phytohemagglutinin-induced proliferation was resistant to x-irradiation with 1,200 rad, either before or after histamine exposure, suggesting that Leu 2+, 9.3- cells need not proliferate to become suppressor cells or exert suppression. Moreover, suppression by these cells was not due to altered kinetics of the response. Finally, a histamine type 2 receptor antagonist (cimetidine) but not a type 1 receptor antagonist (mepyramine) blocked the induction of suppressor cells. On the basis of these results and our previous studies of antigen specific suppressor cells, we conclude that Leu 2+ suppressor cells in man are derived from a precursor pool that is phenotypically distinct from cells that can differentiate into cytotoxic T cells

  14. 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.

  15. Histamine (Scombroid) Fish Poisoning: a Comprehensive Review.

    Science.gov (United States)

    Feng, Charles; Teuber, Suzanne; Gershwin, M Eric

    2016-02-01

    Histamine fish poisoning, also known as scombroid poisoning, is the most common cause of ichythyotoxicosis worldwide and results from the ingestion of histamine-contaminated fish in the Scombroidae and Scomberesocidae families, including mackerel, bonito, albacore, and skipjack. This disease was first described in 1799 in Britain and re-emerged in the medical literature in the 1950s when outbreaks were reported in Japan. The symptoms associated with histamine fish poisoning are similar to that of an allergic reaction. In fact, such histamine-induced reactions are often misdiagnosed as IgE-mediated fish allergy. Indeed, histamine fish poisoning is still an underrecognized disease. In this review, we discuss the epidemiology, pathophysiology, evaluation, and treatment of scombroid disease. Because more than 80% of fish consumed in the USA is now imported from other countries, the disease is intimately linked with the global fish trade (National Marine Fisheries Service, 2012). Preventing future scombroid outbreaks will require that fishermen, public health officials, restaurant workers, and medical professionals work together to devise international safety standards and increase awareness of the disease. The implications of scombroid poisoning go far beyond that of fish and have broader implications for the important issues of food safety.

  16. Stronger Dopamine D1 Receptor-Mediated Neurotransmission in Dyskinesia.

    Science.gov (United States)

    Farré, Daniel; Muñoz, Ana; Moreno, Estefanía; Reyes-Resina, Irene; Canet-Pons, Júlia; Dopeso-Reyes, Iria G; Rico, Alberto J; Lluís, Carme; Mallol, Josefa; Navarro, Gemma; Canela, Enric I; Cortés, Antonio; Labandeira-García, José L; Casadó, Vicent; Lanciego, José L; Franco, Rafael

    2015-12-01

    Radioligand binding assays to rat striatal dopamine D1 receptors showed that brain lateralization of the dopaminergic system were not due to changes in expression but in agonist affinity. D1 receptor-mediated striatal imbalance resulted from a significantly higher agonist affinity in the left striatum. D1 receptors heteromerize with dopamine D3 receptors, which are considered therapeutic targets for dyskinesia in parkinsonian patients. Expression of both D3 and D1-D3 receptor heteromers were increased in samples from 6-hydroxy-dopamine-hemilesioned rats rendered dyskinetic by treatment with 3, 4-dihydroxyphenyl-L-alanine (L-DOPA). Similar findings were obtained using striatal samples from primates. Radioligand binding studies in the presence of a D3 agonist led in dyskinetic, but not in lesioned or L-DOPA-treated rats, to a higher dopamine sensitivity. Upon D3-receptor activation, the affinity of agonists for binding to the right striatal D1 receptor increased. Excess dopamine coming from L-DOPA medication likely activates D3 receptors thus making right and left striatal D1 receptors equally responsive to dopamine. These results show that dyskinesia occurs concurrently with a right/left striatal balance in D1 receptor-mediated neurotransmission.

  17. Influence of preseasonal treatment with L-tyrosine-adsorbed allergoids on IgE-mediated histamine release from basophils of children suffering from allergic diseases.

    Science.gov (United States)

    Wegner, F; Fenkes, A; Stemmann, E A; Reinhardt, D

    1981-04-01

    In 10 children suffering from allergic pollinosis and/or asthma, a preseasonal hyposensitization scheme with 3 weekly injections of a glutaraldehyde-modified, tyrosine-adsorbed grass-pollen allergen reduced the histamine release from basophils in response to increasing concentrations of antigen. The decrease in histamine release which occurred 1 week after the injection course was even maintained during the pollen season. The inhibition was only obtained when basophils were incubated with the serum of patients, but not with the serum of normals, indicating that blocking antibodies may have occurred. In contrast to what has been observed in the treated patients' group, 5 patients, who were not included in the hyposensitization scheme, showed identical histamine release curves during the whole investigation period. Specific IgE did not increase after the treatment course and shows the same behaviour as the untreated patients. Thus, as treatment with glutaraldehyde modified, tyrosine-adsorbed allergoids is safe to administer, requires only 3 injections, reduces histamine release from basophils by production of "blocking" antibodies, it appears to be a useful tool in the hyposensitization treatment.

  18. Effect of histamine-2-receptor antagonists versus sucralfate on stress ulcer prophylaxis in mechanically ventilated patients: a meta-analysis of 10 randomized controlled trials.

    Science.gov (United States)

    Huang, Jiahao; Cao, Yunfei; Liao, Cun; Wu, Liucheng; Gao, Feng

    2010-01-01

    We conducted a meta-analysis in order to investigate the effect of histamine-2-receptor antagonists (H2RA) versus sucralfate on stress ulcer prophylaxis in mechanically ventilated patients in the intensive care unit (ICU). A systematic literature search of Medline, EMBASE, Cochrane Central Register of Controlled Trials (1966 to January 2010) was conducted using specific search terms. A review of Web of Science and a manual review of references were also performed. Eligible studies were randomized control trials (RCTs) that compared H2RA and sucralfate for the prevention of stress ulcer in mechanically ventilated patients. Main outcome measures were rates of overt bleeding, clinically important gastrointestinal (GI) bleeding, ventilator-associated pneumonia, gastric colonization and ICU mortality. Ten RCTs with 2,092 participants on mechanical ventilation were identified. Meta-analysis showed there was a trend toward decreased overt bleeding when H2RA was compared with sucralfate (OR = 0.87, 95% CI: 0.49 to 1.53). A total of 12 clinically important GI bleeding events occurred among 667 patients (1.8%) in the H2RA group compared with 26 events among 673 patients (3.9%) in the sucralfate groups. Prophylaxis with sucralfate decreased the incidence of gastric colonization (OR = 2.03, 95% CI: 1.29 to 3.19) and ventilator-associated pneumonia (OR = 1.32, 95% CI: 1.07 to 1.64). Subgroup analysis showed H2RA was not superior to sucralfate in reducing early-onset pneumonia (OR = 0.62, 95%CI: 0.36 to 1.07) but had a higher late-onset pneumonia rate (OR = 4.36, 95%CI: 2.09 to 9.09) relative to sucralfate. No statistically significant reduction was observed in mortality of ICU between groups (OR = 1.08, 95% CI: 0.86 to 1.34). In patients with mechanical ventilation, H2RA resulted in no differential effectiveness in treating overt bleeding, but had higher rates of gastric colonization and ventilator-associated pneumonia. Additional RCTs of stress ulcer prophylaxis with H2RA and

  19. Potentiodynamic formation of gold nanoparticles film on glassy carbon electrode using aminophenyl diazonium cations grafted gold nanoparticles: Determination of histamine H2 receptor antagonist

    International Nuclear Information System (INIS)

    Kesavan, Srinivasan; Revin, S. Brillians; John, S. Abraham

    2014-01-01

    Graphical abstract: - Highlights: • Grafting based AuNPs were synthesized in aqueous medium by spontaneous grafting. • GC/ITO electrode was modified with AuNPs film by potentiodynamic method. • AuNPs film modified electrode was characterized by XPS, AFM and CV. • Simultaneous determination of ranitidine and paracetamol was demonstrated. • Practical application was demonstrated in commercial drugs. - Abstract: The aminophenyl (AP) functionalized AuNPs (AP-AuNPs) were synthesized in aqueous medium by spontaneous grafting method and were used for the formation of AuNPs film on glassy carbon (GC) and indium tin oxide (ITO) surfaces by potentiodynamic method. The formed AP-AuNPs film modified electrodes were characterized by cyclic voltammetry (CV), atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). EIS studies show that the electron transfer reaction of [Fe(CN) 6 ] 3-/4− was higher at the AP-AuNPs film modified electrode (1.58 × 10 −4 cm s −1 ) than at bare (3.78 × 10 −5 cm s −1 ) GC electrode. The surface coverage of the AP-AuNPs film modified electrode was found to be 4.4 × 10 −10 mol cm −2 . The film formation takes place via -NH 2 groups of AP-AuNPs, which was confirmed by XPS from the observed peaks corresponding to =N-H (396.7 eV), -N-H (399.2 eV), -N = N- (400.2 eV) and -N + -H (403.3 eV). The AP-AuNPs film modified electrode was successfully utilized for the determination of histamine H 2 receptor antagonist ranitidine (RA). Further, the AP-AuNPs film modified electrode was effectively used for the selective determination of RA in the presence of 40-fold excess paracetamol. The present method was successfully used to determine the concentration of RA in commercial drugs

  20. Serum diamine oxidase activity in patients with histamine intolerance.

    Science.gov (United States)

    Manzotti, G; Breda, D; Di Gioacchino, M; Burastero, S E

    2016-03-01

    Intolerance to various foods, excluding bona fide coeliac disease and lactose intolerance, represents a growing cause of patient visits to allergy clinics.Histamine intolerance is a long-known, multifaceted clinical condition triggered by histamine-rich foods and alcohol and/or by drugs that liberate histamine or block diamine oxidase (DAO), the main enzyme involved in the metabolism of ingested histamine. Histamine limitation diets impose complex, non-standardized restrictions that may severely impact the quality of life of patients. We retrospectively evaluated 14 patients who visited allergy outpatient facilities in northern Italy with a negative diagnosis for IgE-mediated food hypersensitivity, coeliac disease, conditions related to gastric hypersecretion, and systemic nickel hypersensitivity, and who previously underwent a histamine limitation diet with benefits for their main symptoms. Serum diamine oxidase levels and the clinical response to diamine oxidase supplementation were investigated. We found that 10 out of 14 patients had serum DAO activityintolerance. Moreover, 13 out of 14 patients subjectively reported a benefit in at least one of the disturbances related to food intolerances following diamine oxidase supplementation. The mean value (±SD) of diamine oxidase activity in the cohort of patients with histamine intolerance symptoms was 7.04±6.90 U/mL compared to 39.50±18.16 U/mL in 34 healthy controls (P=0.0031). In patients with symptoms triggered by histamine-rich food, measuring the serum diamine oxidase activity can help identify subjects who can benefit from a histamine limitation diet and/or diamine oxidase supplementation.Properly designed, controlled studies investigating histamine intolerance that include histamine provocation are indispensable for providing insights into the area of food intolerances, which are currently primarily managed with non-scientific approaches in Italy. © The Author(s) 2015.

  1. Fenspiride inhibits histamine-induced responses in a lung epithelial cell line.

    Science.gov (United States)

    Quartulli, F; Pinelli, E; Broué-Chabbert, A; Gossart, S; Girard, V; Pipy, B

    1998-05-08

    Using the human lung epithelial WI26VA4 cell line, we investigated the capacity of fenspiride, an anti-inflammatory drug with anti-bronchoconstrictor properties, to interfere with histamine-induced intracellular Ca2+ increase and eicosanoid formation. Histamine and a histamine H1 receptor agonist elicited a rapid and transient intracellular Ca2+ increase (0-60 s) in fluo 3-loaded WI26VA4 cells. This response was antagonized by the histamine H1 receptor antagonist, diphenhydramine, the histamine H2 receptor antagonist, cimetidine, having no effect. Fenspiride (10(-7)-10(-5) M) inhibited the histamine H1 receptor-induced Ca2+ increase. In addition, histamine induced a biphasic increase in arachidonic acid release. The initial rise (0-30 s), a rapid and transient arachidonic acid release, was responsible for the histamine-induced intracellular Ca2+ increase. In the second phase release (15-60 min), a sustained arachidonic acid release appeared to be associated with the formation of cyclooxygenase and lipoxygenase metabolites. Fenspiride (10(-5) M) abolished both phases of histamine-induced arachidonic acid release. These results suggest that anti-inflammatory and antibronchoconstrictor properties of fenspiride may result from the inhibition of these effects of histamine.

  2. Molecular Mechanisms of Dopamine Receptor Mediated Neuroprotection

    National Research Council Canada - National Science Library

    Sealfon, Stuart

    2000-01-01

    ... of the cellular changes characteristic of this process. Evidence from our laboratory and others suggest that activation of dopamine receptors can oppose the induction of apoptosis in dopamine neurons...

  3. Histamine and Tyramine in Food.

    Science.gov (United States)

    1985-05-01

    FISH PRODUCTS 44 ON THE JAPANESE MARKET TABLE 4-9 TYRAMINE AND HISTAMINE IN FRUITS, 48 VEGETABLES AND THEIR PRODUCTS TABLE 5-1 SCOMBROTOXIN (HISTAMINE...Products The histamine and tyramine content of fruits, vegetables and their products is shown in Table 4-9. The fruits of avocado , lemon, and...VEGETABLES, AND THEIR PRODUCTS (ug/g) ITEM HISTAMINE TYRAMINE REFERENCE Apple 0 6 Avocado 23 78 Bananas 7 79, 80, 81, 82 Banana Peel - 65 81 Barley - 10

  4. 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.

  5. Radiosynthesis and biodistribution of a histamine H3 receptor antagonist 4-[3-(4-piperidin-1-yl-but-1-ynyl)-[11C]benzyl]-morpholine: evaluation of a potential PET ligand

    International Nuclear Information System (INIS)

    Airaksinen, Anu J.; Jablonowski, Jill A.; Mey, Margreet van der; Barbier, Ann J.; Klok, Rob P.; Verbeek, Joost; Schuit, Robert; Herscheid, Jacobus D.M.; Leysen, Josee E.; Carruthers, Nicholas I.; Lammertsma, Adriaan A.; Windhorst, Albert D.

    2006-01-01

    The potent histamine H 3 receptor antagonist JNJ-10181457 () was successfully labeled with 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/μmol). The binding of [ 11 C] to H 3 receptors was studied in vitro in rat brain and in vivo in rats and mice. The in vitro binding of [ 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 3 antagonists, JNJ-5207852 () and unlabeled Compound (), in a concentration-dependent manner. The biodistribution of [ 11 C] in rats was measured at 5, 10, 30 and 60 min. The uptake of [ 11 C] in regions rich in H 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 [ 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 [ 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 3 (-/-) knockout mice, a higher brain uptake was also observed. Analyses of metabolites and plasma protein binding were also undertaken. It appeared that [ 11 C] could not specifically label H 3 receptors in rodent brain in vivo. Possible causes are discussed

  6. Relations between immune and mediator receptors of mouse lymphocytes

    International Nuclear Information System (INIS)

    Ado, A.D.; Alekseeva, T.A.; Kravchenko, S.A.

    1985-01-01

    This paper examines the action of the specific muscarinic antogonist tritium-quinuclidinyl benzilate (tritium-QNB) on immune rosette formation in mice. It is shown that since the specific muscarini antagonist tritium-QNB inhibits immune rosette formation, this process must be regarded as interconnected with muscarinic receptors of lymphocytes. Interaction of immune (antigen-binding) and mediator receptors, however, is an important factor maintaining immune homeostasis at a certain level

  7. On the role of serotonin and histamine in neurohumoral mechanisms of postirradiation diarrhea in rats

    International Nuclear Information System (INIS)

    Legeza, V.I.; Shagoyan, M.G.; Markovskaya, I.V.; Vasil'eva, T.P.; Pozharisskaya, T.D.; Alekseeva, I.I.; Lokteva, O.I.

    1990-01-01

    In experiments with rats exposed to 200 Gy radiation it was shown that the diarrhea effect of serotonin under the effect of radiation is implemented via D- and M-type receptors, and that of histamine via H 1 and H 2 receptors. Serotonin and histamine, that were released under the effect of radiation from endocrine and mast cells of the digestive tract stimulated the propulsion activity of the intestine whereas histamine, in addition, inhibited the absorption process. It is suggested that serotonin and histamine antagonists should be used as means of preventing of radiation-induced diarrhea

  8. Adrenergic receptors and gastric acid secretion in dogs. The influence of beta 2-receptors

    DEFF Research Database (Denmark)

    Gottrup, F; Hovendal, C; Bech, K

    1984-01-01

    the characteristics of a non-competitive mechanism, while the weaker inhibition of histamine induced acid output seemed to follow a competitive mechanism. The inhibitory effect was not mediated through a decreased gastrin release. Dopamine receptor blockade was found to be without any influence on the inhibitory...

  9. 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.

  10. Opioid receptor mediated anticonvulsant effect of pentazocine.

    Science.gov (United States)

    Khanna, N; Khosla, R; Kohli, J

    1998-01-01

    Intraperitoneal (i.p.) administration of (+/-) pentazocine (10, 30 & 50 mg/kg), a Sigma opioid agonist, resulted in a dose dependent anticonvulsant action against maximal electroshock seizures in mice. This anticonvulsant effect of pentazocine was not antagonized by both the doses of naloxone (1 and 10 mg/kg) suggesting thereby that its anticonvulsant action is probably mediated by Sigma opiate binding sites. Its anticonvulsant effect was potentiated by both the anticonvulsant drugs viz. diazepam and diphenylhydantoin. Morphine, mu opioid agonist, on the other hand, failed to protect the animals against maximal electroshock seizures when it was given in doses of 10-40 mg/kg body wt.

  11. The effects of thermal stimuli on intracellular calcium change and histamine releases in rat basophilic leukemia mast cells

    Science.gov (United States)

    Wu, Zu-Hui; Zhu, Dan; Chen, Ji-Yao; Zhou, Lu-Wei

    2012-05-01

    The effects of thermal stimuli on rat basophilic leukemia mast cells were studied. The cells in calcium-contained or calcium-free buffers were thermally stimulated in the temperature range of 25-60 °C. The corresponding calcium ion concentration in cells [Ca2+]i as well as the released histamine from cells was measured with fluorescence staining methods. The ruthenium red (RR), a block of membrane calcium channels (transient receptor potential family V (TRPV)), was used in experiments. Under the stimulus of 25-50 °C, no significant difference on [Ca2+]i was found between these three groups of the cells in calcium-contained buffer without or with RR and cells in calcium-free saline, indicating that the increased calcium in cytosol did not result from the extracellular buffer but came from the intracellular calcium stores. The [Ca2+]i continuously increased under the temperature of 50-60 °C, but the RR and calcium-free saline can obviously diminish the [Ca2+]i increase at these high temperatures, reflecting that the opening of the TRPV2 channels leads to a calcium influx resulting in the [Ca2+]i increment. The histamine release also became significant in these cases. Since the released histamine is a well-known mediator for the microcirculation promotion, the histamine release from mast cells could be one of the mechanisms of thermal therapy.

  12. Cytopathology and exocrine dysfunction induced in ex vivo rabbit lacrimal gland acinar cell models by chronic exposure to histamine or serotonin.

    Science.gov (United States)

    McDonald, Michelle L; Wang, Yanru; Selvam, Shivaram; Nakamura, Tamako; Chow, Robert H; Schechter, Joel E; Yiu, Samuel C; Mircheff, Austin K

    2009-07-01

    Lacrimal immunohistopathology has diverse clinical presentations, suggesting that inflammatory mediators exert diverse influences. Chronic exposure to agonistic acetylcholine receptor autoantibodies has been studied previously; the present work addressed mediators that signal through other G protein-coupled receptors. Acinus-like structures and reconstituted acinar epithelial monolayers from rabbit lacrimal glands were exposed to varying concentrations of histamine or 5-hydroxytryptamine (5-HT) for 20 hours. Net and vectorial beta-hexosaminidase secretion, cytosolic Ca(2+) (Ca(i)) elevation, apical recruitment of p150(Glued), actin microfilament meshwork organization, and ultrastructure were assessed. Histamine and 5-HT acutely stimulated beta-hexosaminidase secretion at lower, but not higher, concentrations. Neither of them acutely elevated Ca(i) levels. Both recruited p150(Glued) at concentrations that failed to induce secretion. Chronic exposure to 10 mM histamine inhibited carbachol (CCh)-induced beta-hexosaminidase secretion and prevented the formation of continuous monolayers; 1 mM 5-HT partially inhibited secretion at the apical medium. Neither altered secretion to the basal medium. Chronic exposure to histamine or 5-HT partially decreased CCh induced Ca(i) elevations and p150(Glued) recruitment, even at concentrations that did not inhibit secretion. Both expanded acinar lumina and thickened microfilament meshworks, and both caused homotypic fusion of secretory vesicles and formation of aqueous vacuoles in the apical and basal cytoplasm. Chronic exposure to forskolin, which activates adenylyl cyclase, induced similar cytopathologic changes but impaired secretion modestly and only at the highest concentration tested. Inflammatory mediators that signal through G protein-coupled receptors cause acinar cell cytopathology and dose-dependent reductions of CCh-induced beta-hexosaminidase secretion. Although agonistic acetylcholine receptor autoantibodies may cause

  13. Interactions of the histamine and hypocretin systems in CNS disorders.

    Science.gov (United States)

    Shan, Ling; Dauvilliers, Yves; Siegel, Jerome M

    2015-07-01

    Histamine and hypocretin neurons are localized to the hypothalamus, a brain area critical to autonomic function and sleep. Narcolepsy type 1, also known as narcolepsy with cataplexy, is a neurological disorder characterized by excessive daytime sleepiness, impaired night-time sleep, cataplexy, sleep paralysis and short latency to rapid eye movement (REM) sleep after sleep onset. In narcolepsy, 90% of hypocretin neurons are lost; in addition, two groups reported in 2014 that the number of histamine neurons is increased by 64% or more in human patients with narcolepsy, suggesting involvement of histamine in the aetiology of this disorder. Here, we review the role of the histamine and hypocretin systems in sleep-wake modulation. Furthermore, we summarize the neuropathological changes to these two systems in narcolepsy and discuss the possibility that narcolepsy-associated histamine abnormalities could mediate or result from the same processes that cause the hypocretin cell loss. We also review the changes in the hypocretin and histamine systems, and the associated sleep disruptions, in Parkinson disease, Alzheimer disease, Huntington disease and Tourette syndrome. Finally, we discuss novel therapeutic approaches for manipulation of the histamine system.

  14. Induction of aryl hydrocarbon receptor-mediated and estrogen receptor-mediated activities, and modulation of cell proliferation by dinaphthofurans

    Czech Academy of Sciences Publication Activity Database

    Vondráček, Jan; Chramostová, Kateřina; Plíšková, M.; Bláha, L.; Brack, W.; Kozubík, Alois; Machala, M.

    2004-01-01

    Roč. 23, č. 9 (2004), s. 2214-2220 ISSN 0730-7268 R&D Projects: GA ČR GA525/03/1527 Institutional research plan: CEZ:AV0Z5004920 Keywords : aryl hydrocarbon receptor-mediated activity * estrogenicity * intercellular communication inhibition Subject RIV: BO - Biophysics Impact factor: 2.121, year: 2004

  15. The effect of betahistine, a histamine H1 receptor agonist/H3 antagonist, on olanzapine-induced weight gain in first-episode schizophrenia patients.

    Science.gov (United States)

    Poyurovsky, Michael; Pashinian, Artashes; Levi, Aya; Weizman, Ronit; Weizman, Abraham

    2005-03-01

    Histamine antagonism has been implicated in antipsychotic drug-induced weight gain. Betahistine, a histamine enhancer with H1 agonistic/H3 antagonistic properties (48 mg t.i.d.), was coadministered with olanzapine (10 mg/day) in three first-episode schizophrenia patients for 6 weeks. Body weight was measured at baseline and weekly thereafter. Clinical rating scales were completed at baseline and at week 6. All participants gained weight (mean weight gain 3.1+/-0.9 kg) and a similar pattern of weight gain was observed: an increase during the first 2 weeks and no additional weight gain (two patients) or minor weight loss (one patient) from weeks 3 to 6. None gained 7% of baseline weight, which is the cut-off for clinically significant weight gain. Betahistine was safe and well tolerated and did not interfere with the antipsychotic effect of olanzapine. Our findings justify a placebo-controlled evaluation of the putative weight-attenuating effect of betahistine in olanzapine-induced weight gain.

  16. Fcγ receptor-mediated inflammation inhibits axon regeneration.

    Directory of Open Access Journals (Sweden)

    Gang Zhang

    Full Text Available Anti-glycan/ganglioside antibodies are the most common immune effectors found in patients with Guillain-Barré Syndrome, which is a peripheral autoimmune neuropathy. We previously reported that disease-relevant anti-glycan autoantibodies inhibited axon regeneration, which echo the clinical association of these antibodies and poor recovery in Guillain-Barré Syndrome. However, the specific molecular and cellular elements involved in this antibody-mediated inhibition of axon regeneration are not previously defined. This study examined the role of Fcγ receptors and macrophages in the antibody-mediated inhibition of axon regeneration. A well characterized antibody passive transfer sciatic nerve crush and transplant models were used to study the anti-ganglioside antibody-mediated inhibition of axon regeneration in wild type and various mutant and transgenic mice with altered expression of specific Fcγ receptors and macrophage/microglia populations. Outcome measures included behavior, electrophysiology, morphometry, immunocytochemistry, quantitative real-time PCR, and western blotting. We demonstrate that the presence of autoantibodies, directed against neuronal/axonal cell surface gangliosides, in the injured mammalian peripheral nerves switch the proregenerative inflammatory environment to growth inhibitory milieu by engaging specific activating Fcγ receptors on recruited monocyte-derived macrophages to cause severe inhibition of axon regeneration. Our data demonstrate that the antibody orchestrated Fcγ receptor-mediated switch in inflammation is one mechanism underlying inhibition of axon regeneration. These findings have clinical implications for nerve repair and recovery in antibody-mediated immune neuropathies. Our results add to the complexity of axon regeneration in injured peripheral and central nervous systems as adverse effects of B cells and autoantibodies on neural injury and repair are increasingly recognized.

  17. The role of histamine in estradiol-induced conditioned consumption reductions.

    Science.gov (United States)

    Hintiryan, Houri; Hayes, Unja L; Chambers, Kathleen C

    2005-01-31

    Conditioned consumption reductions (CCRs) develop toward novel taste stimuli as a consequence of associating those tastes with certain physiological changes. Few studies have focused on the neurochemical basis of this learned behavior. The purpose of these experiments was to reexamine the role of histamine in CCRs elicited by estradiol. Previous studies have suggested that histamine mediates CCRs induced by radiation, centrifugal rotation, and estradiol. However, because the animals were trained in a drug state, but tested in a nondrug state, it is possible that state-dependent learning confounded the results of these studies. The following series of experiments was performed to test this possibility for estradiol-induced CCRs. Implementing our own methodologies in Experiment 1, we demonstrated that an estradiol-induced CCR was blocked by treatment with the histamine 1 receptor blocker, chlorpheniramine maleate, before sucrose consumption during acquisition. In Experiment 2, identical states were maintained during acquisition and extinction by administering chlorpheniramine prior to sucrose exposure during both phases. The results indicated that chlorpheniramine blocked the estradiol-induced CCR. However, circumventing state-dependency in Experiment 3 by administering chlorpheniramine following exposure to sucrose during acquisition augmented the estradiol CCR. Taken together, the results of these experiments suggest that the ability of chlorpheniramine to abolish estradiol-induced CCRs is not due to state-dependency or to the antihistaminergic properties of chlorpheniramine. It is proposed that the results of all of the experiments can be accounted for by the aversive properties of chlorpheniramine.

  18. 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.

  19. The pathophysiological functions mediated by D-1 dopamine receptors

    International Nuclear Information System (INIS)

    Goldstein, M.; Kuga, S.; Meller, E.; SHimizu, Y.

    1986-01-01

    This chapter describes some behavioral responses which might be mediated by D 1 and D 2 DA receptors, and the authors discuss their clinical relevance. It was of considerable interest to determine whether a selective D 1 DA antagonist, such as SCH 23390, will induce catalepsy and whether this behavior is mediated by D 1 , or by both D 1 and D 2 DA receptors. Rats were used in the experiments. The authors examined whether the addition of the S 2 antagonist ketanserin affects the displacement of 3 H-Spi by SCH 23390. Induction of self-mutilating biting (SMB) behavior in monkeys with unilateral ventromedial tegmental (VMT) lesions by DA agonists and its prevention by DA antagonists is examined. The authors also discuss the possible relationships between abnormal guanine nucleotide metabolism and dopaminergic neuronal function through the implications in LeschNyhan syndrome and in some mental disorders

  20. Tryptase potentiates enteric nerve activation by histamine and serotonin: Relevance for the effects of mucosal biopsy supernatants from irritable bowel syndrome patients.

    Science.gov (United States)

    Ostertag, D; Annahazi, A; Krueger, D; Michel, K; Demir, I E; Ceyhan, G O; Zeller, F; Schemann, M

    2017-09-01

    We previously showed that mucosal biopsy supernatants from irritable bowel syndrome patients activated neurons despite low concentrations of tryptase, histamine, and serotonin which individually would not cause spike discharge. We studied the potentiating responses between these mediators on excitability of enteric neurons. Calcium-imaging was performed using the calcium-sensitive dye Fluo-4 AM in human submucous plexus preparations from 45 individuals. Histamine, serotonin, and tryptase were applied alone and in combinations to evaluate nerve activation which was assessed by analyzing increase in intracellular Ca 2+ ([Ca 2+ ] i ), the proportion of responding neurons and the product of both defined as Ca-neuroindex (NI). Protease activated receptor (PAR) 2 activating peptide, PAR2 antagonist and the serine protease-inhibitor FUT-175 were used to particularly investigate the role of proteases. Histamine or serotonin (1 μmol/L each) evoked only few small responses (median NI [25%/75%]: 0 [0/148]; 85 [0/705] respectively). Their combined application evoked statistically similar responses (216 [21/651]). Addition of the PAR2 activator tryptase induced a significantly higher Ca-NI (1401 [867/4075]) compared to individual application of tryptase or to coapplied histamine and serotonin. This synergistic potentiation was neither mimicked by PAR2 activating peptide nor reversed by the PAR2 antagonist GB83, but abolished by FUT-175. We observed synergistic potentiation between histamine, serotonin, and tryptase in enteric neurons, which is mediated by proteolytic activity rather than PAR2 activation. This explained neuronal activation by a cocktail of these mediators despite their low concentrations and despite a relatively small PAR2-mediated response in human submucous neurons. © 2017 John Wiley & Sons Ltd.

  1. Receptor-mediated gene delivery using chemically modified chitosan

    International Nuclear Information System (INIS)

    Kim, T H; Jiang, H L; Nah, J W; Cho, M H; Akaike, T; Cho, C S

    2007-01-01

    Chitosan has been investigated as a non-viral vector because it has several advantages such as biocompatibility, biodegradability and low toxicity with high cationic potential. However, the low specificity and low transfection efficiency of chitosan need to be solved prior to clinical application. In this paper, we focused on the galactose or mannose ligand modification of chitosan for enhancement of cell specificity and transfection efficiency via receptor-mediated endocytosis in vitro and in vivo

  2. Purinergic Receptors: Key Mediators of HIV-1 infection and inflammation

    Directory of Open Access Journals (Sweden)

    Talia H Swartz

    2015-11-01

    Full Text Available Human immunodeficiency virus (HIV-1 causes a chronic infection that afflicts more than 38 million individuals worldwide. While the infection can be suppressed with potent anti-retroviral therapies, individuals infected with HIV have elevated levels of inflammation as indicated by increased T cell activation, soluble biomarkers, and associated morbidity and mortality. A single mechanism linking HIV pathogenesis to this inflammation has yet to be identified. Purinergic receptors are known to mediate inflammation and have been shown to be required for HIV-1 infection at the level of HIV-1 membrane fusion. Here we review the literature on the role of purinergic receptors in HIV-1 infection and associated inflammation and describe a role for these receptors as potential therapeutic targets.

  3. Of pheromones and kairomones: what receptors mediate innate emotional responses?

    Science.gov (United States)

    Fortes-Marco, Lluis; Lanuza, Enrique; Martinez-Garcia, Fernando

    2013-09-01

    Some chemicals elicit innate emotionally laden behavioral responses. Pheromones mediate sexual attraction, parental care or agonistic confrontation, whereas predators' kairomones elicit defensive behaviors in their preys. This essay explores the hypothesis that the detection of these semiochemicals relies on highly specific olfactory and/or vomeronasal receptors. The V1R, V2R, and formyl-peptide vomeronasal receptors bind their ligands in highly specific and sensitive way, thus being good candidates for pheromone- or kairomone-detectors (e.g., secreted and excreted proteins, peptides and lipophilic volatiles). The olfactory epithelium also expresses specific receptors, for example trace amine-associated receptors (TAAR) and guanylyl cyclase receptors (GC-D and other types), some of which bind kairomones and putative pheromones. However, most of the olfactory neurons express canonical olfactory receptors (ORs) that bind many ligands with different affinity, being not suitable for mediating responses to pheromones and kairomones. In this respect, trimethylthiazoline (TMT) is considered a fox-derived kairomone for mice and rats, but it seems to be detected by canonical ORs. Therefore, we have reassessed the kairomonal nature of TMT by analyzing the behavioral responses of outbred (CD1) and inbred mice (C57BL/J6) to TMT. Our results confirm that both mouse strains avoid TMT, which increases immobility in C57BL/J6, but not CD1 mice. However, mice of both strains sniff at TMT throughout the test and show no trace of TMT-induced contextual conditioning (immobility or avoidance). This suggests that TMT is not a kairomone but, similar to a loud noise, in high concentrations it induces aversion and stress as unspecific responses to a strong olfactory stimulation. Copyright © 2013 Wiley Periodicals, Inc.

  4. Comparison of in vitro histamine release by ionic and nonionic radiographyic contrast media

    International Nuclear Information System (INIS)

    Faraj, B.A.; Martin, L.G.

    1989-01-01

    This paper discusses a study whose results showed that in 53 hospitalized patients undergoing cardiovascular catheterization, incubation of their blood samples with varying concentrations of an ionic contrast medium (Angiovist-370, 60--631 mM) induced a significant (P < .005) amount of histamine release from whole blood (3.5%--10%), as compared with the histamine release following incubation with a nonionic contrast medium. Data suggest that the use of nonionic contrast media may induce minimal histamine release and thereby involve less patient risk from the histamine-mediated allergic and hemodynamic side effects associated with radiographic contrast media procedures

  5. BF2.649 [1-{3-[3-(4-Chlorophenyl)propoxy]propyl}piperidine, hydrochloride], a nonimidazole inverse agonist/antagonist at the human histamine H3 receptor: Preclinical pharmacology.

    Science.gov (United States)

    Ligneau, X; Perrin, D; Landais, L; Camelin, J-C; Calmels, T P G; Berrebi-Bertrand, I; Lecomte, J-M; Parmentier, R; Anaclet, C; Lin, J-S; Bertaina-Anglade, V; la Rochelle, C Drieu; d'Aniello, F; Rouleau, A; Gbahou, F; Arrang, J-M; Ganellin, C R; Stark, H; Schunack, W; Schwartz, J-C

    2007-01-01

    Histamine H3 receptor inverse agonists are known to enhance the activity of histaminergic neurons in brain and thereby promote vigilance and cognition. 1-{3-[3-(4-Chlorophenyl)propoxy]propyl}piperidine, hydrochloride (BF2.649) is a novel, potent, and selective nonimidazole inverse agonist at the recombinant human H3 receptor. On the stimulation of guanosine 5'-O-(3-[35S]thio)triphosphate binding to this receptor, BF2.649 behaved as a competitive antagonist with a Ki value of 0.16 nM and as an inverse agonist with an EC50 value of 1.5 nM and an intrinsic activity approximately 50% higher than that of ciproxifan. Its in vitro potency was approximately 6 times lower at the rodent receptor. In mice, the oral bioavailability coefficient, i.e., the ratio of plasma areas under the curve after oral and i.v. administrations, respectively, was 84%. BF2.649 dose dependently enhanced tele-methylhistamine levels in mouse brain, an index of histaminergic neuron activity, with an ED50 value of 1.6 mg/kg p.o., a response that persisted after repeated administrations for 17 days. In rats, the drug enhanced dopamine and acetylcholine levels in microdialysates of the prefrontal cortex. In cats, it markedly enhanced wakefulness at the expense of sleep states and also enhanced fast cortical rhythms of the electroencephalogram, known to be associated with improved vigilance. On the two-trial object recognition test in mice, a promnesiant effect was shown regarding either scopolamine-induced or natural forgetting. These preclinical data suggest that BF2.649 is a valuable drug candidate to be developed in wakefulness or memory deficits and other cognitive disorders.

  6. Role of desensitization and subunit expression for kainate receptor-mediated neurotoxicity in murine neocortical cultures

    DEFF Research Database (Denmark)

    Jensen, J B; Schousboe, A; Pickering, D S

    1999-01-01

    ) toxicity mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors, and (3) toxicity that can be mediated by kainate receptors when desensitization of the receptors is blocked. The indirect action at NMDA receptors was discovered because (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H...... nedioxy-5H-2,3-benzodiazepine (GYKI 53655), a selective AMPA receptor antagonist, abolished the remaining toxicity. These results indicated that kainate- and domoate-mediated toxicity involves both the NMDA and the AMPA receptors. Pretreatment of the cultures with concanavalin A to prevent desensitization...

  7. DMPD: Modulation of Toll-interleukin 1 receptor mediated signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15662540 Modulation of Toll-interleukin 1 receptor mediated signaling. Li X, Qin J.... J Mol Med. 2005 Apr;83(4):258-66. Epub 2005 Jan 21. (.png) (.svg) (.html) (.csml) Show Modulation of Toll-i...nterleukin 1 receptor mediated signaling. PubmedID 15662540 Title Modulation of Toll-interleukin 1 receptor

  8. AMPA receptor mediated excitotoxicity in neocortical neurons is developmentally regulated and dependent upon receptor desensitization

    DEFF Research Database (Denmark)

    Jensen, J B; Schousboe, A; Pickering, D S

    1998-01-01

    with a fast and rapidly desensitizing response, this could explain the relatively low toxicity produced by 500 microM AMPA. This was investigated by blocking AMPA receptor desensitization with cyclothiazide. Using a lower concentration (25 microM) of AMPA, addition of 50 microM cyclothiazide increased...... the AMPA induced excitotoxicity in cultured cortical neurons at all DIV except for DIV 2. This combination of AMPA + cyclothiazide yielded 77% cell death for DIV 12 cultures. In contrast to the results observed with 500 microM AMPA, the neurotoxicity mediated directly by AMPA receptors when desensitization...

  9. Blood histamine release: A new allergy blood test

    International Nuclear Information System (INIS)

    Faraj, B.A.; Gottlieb, G.R.; Camp, V.M.; Lollies, P.

    1985-01-01

    Allergen-mediated histamine release from human leukocytes represents an important model for in vitro studies of allergic reactions. The purpose of this study was to determine whether the measurement of histamine released in allergic patients (pts) by radioenzymatic assay following mixing of their blood with common allergens represents a reliable index for diagnosis of atopic allergy. Three categories of allergies were used: (1) housedust and mite; (2) cat and dog dander; (3) trees and grasses and ragweed mixture. The presence of allergy was established by intradermal skin testing in the study group of 82 pts. Significant atopy was defined as ≥ 3+ (overall range 0-4 +, negative to maximum) on skin testing. The test was carried out in tubes with 0.5 ml heparinized blood, 0.5 ml tris albumin buffer, and one of the allergens (60-100 PNU/ml). In 20 controls without allergy, there always was ≤ 4% histamine release (normal response). A significant allergen-mediated histamine release, ranging from 12 to 30% of the total blood histamine content, was observed in 96% of the pts with skin test sensitivity of ≥ 3+. There was good agreement between skin testing and histamine release in terms of the allergen causing the response. Thus, measurement of histamine release in blood in response to allergen challenge represents a clinically useful in vitro test for the diagnosis of atopic allergy. Because data can be obtained from a single sample and are highly quantitative, this new method should have application to the longitudinal study of allergic pts and to the assessment of interventions

  10. Receptor-Mediated Endocytosis and Brain Delivery of Therapeutic Biologics

    Directory of Open Access Journals (Sweden)

    Guangqing Xiao

    2013-01-01

    Full Text Available Transport of macromolecules across the blood-brain-barrier (BBB requires both specific and nonspecific interactions between macromolecules and proteins/receptors expressed on the luminal and/or the abluminal surfaces of the brain capillary endothelial cells. Endocytosis and transcytosis play important roles in the distribution of macromolecules. Due to the tight junction of BBB, brain delivery of traditional therapeutic proteins with large molecular weight is generally not possible. There are multiple pathways through which macromolecules can be taken up into cells through both specific and nonspecific interactions with proteins/receptors on the cell surface. This review is focused on the current knowledge of receptor-mediated endocytosis/transcytosis and brain delivery using the Angiopep-2-conjugated system and the molecular Trojan horses. In addition, the role of neonatal Fc receptor (FcRn in regulating the efflux of Immunoglobulin G (IgG from brain to blood, and approaches to improve the pharmacokinetics of therapeutic biologics by generating Fc fusion proteins, and increasing the pH dependent binding affinity between Fc and FcRn, are discussed.

  11. Loss of Melanopsin Photoreception and Antagonism of the Histamine H3 Receptor by Ciproxifan Inhibit Light-Induced Sleep in Mice.

    Directory of Open Access Journals (Sweden)

    Fanuel Muindi

    Full Text Available Light has direct effects on sleep and wakefulness causing arousal in diurnal animals and sleep in nocturnal animals. In the present study, we assessed the modulation of light-induced sleep by melanopsin and the histaminergic system by exposing mice to millisecond light flashes and continuous light respectively. First, we show that the induction of sleep by millisecond light flashes is dose dependent as a function of light flash number. We found that exposure to 60 flashes of light occurring once every 60 seconds for 1-h (120-ms of total light over an hour induced a similar amount of sleep as a continuous bright light pulse. Secondly, the induction of sleep by millisecond light flashes was attenuated in the absence of melanopsin when animals were presented with flashes occurring every 60 seconds over a 3-h period beginning at ZT13. Lastly, the acute administration of a histamine H3 autoreceptor antagonist, ciproxifan, blocked the induction of sleep by a 1-h continuous light pulse during the dark period. Ciproxifan caused a decrease in NREMS delta power and an increase in theta activity during both sleep and wake periods respectively. The data suggest that some form of temporal integration occurs in response to millisecond light flashes, and that this process requires melanopsin photoreception. Furthermore, the pharmacological data suggest that the increase of histaminergic neurotransmission is sufficient to attenuate the light-induced sleep response during the dark period.

  12. Environmental phthalate monoesters activate pregnane X receptor-mediated transcription

    International Nuclear Information System (INIS)

    Hurst, Christopher H.; Waxman, David J.

    2004-01-01

    Phthalate esters, widely used as plasticizers in the manufacture of products made of polyvinyl chloride, induce reproductive and developmental toxicities in rodents. The mechanism that underlies these effects of phthalate exposure, including the potential role of members of the nuclear receptor superfamily, is not known. The present study investigates the effects of phthalates on the pregnane X receptor (PXR), which mediates the induction of enzymes involved in steroid metabolism and xenobiotic detoxification. The ability of phthalate monoesters to activate PXR-mediated transcription was assayed in a HepG2 cell reporter assay following transfection with mouse PXR (mPXR), human PXR (hPXR), or the hPXR allelic variants V140M, D163G, and A370T. Mono-2-ethylhexyl phthalate (MEHP) increased the transcriptional activity of both mPXR and hPXR (5- and 15-fold, respectively) with EC 50 values of 7-8 μM. mPXR and hPXR were also activated by monobenzyl phthalate (MBzP, up to 5- to 6-fold) but were unresponsive to monomethyl phthalate and mono-n-butyl phthalate (M(n)BP) at the highest concentrations tested (300 μM). hPXR-V140M and hPXR-A370T exhibited patterns of phthalate responses similar to the wild-type receptor. By contrast, hPXR-D163G was unresponsive to all phthalate monoesters tested. Further studies revealed that hPXR-D163G did respond to rifampicin, but required approximately 40-fold higher concentrations than wild-type receptor, suggesting that the ligand-binding domain D163G variant has impaired ligand-binding activity. The responsiveness of PXR to activation by phthalate monoesters demonstrated here suggests that these ubiquitous environmental chemicals may, in part, exhibit their endocrine disruptor activities by altering PXR-regulated steroid hormone metabolism with potential adverse health effects in exposed individuals

  13. Microglia P2Y13 Receptors Prevent Astrocyte Proliferation Mediated by P2Y1 Receptors

    Directory of Open Access Journals (Sweden)

    Clara Quintas

    2018-05-01

    Full Text Available Cerebral inflammation is a common feature of several neurodegenerative diseases that requires a fine interplay between astrocytes and microglia to acquire appropriate phenotypes for an efficient response to neuronal damage. During brain inflammation, ATP is massively released into the extracellular medium and converted into ADP. Both nucleotides acting on P2 receptors, modulate astrogliosis through mechanisms involving microglia-astrocytes communication. In previous studies, primary cultures of astrocytes and co-cultures of astrocytes and microglia were used to investigate the influence of microglia on astroglial proliferation induced by ADPβS, a stable ADP analog. In astrocyte cultures, ADPβS increased cell proliferation through activation of P2Y1 and P2Y12 receptors, an effect abolished in co-cultures (of astrocytes with ∼12.5% microglia. The possibility that the loss of the ADPβS-mediated effect could have been caused by a microglia-induced degradation of ADPβS or by a preferential microglial localization of P2Y1 or P2Y12 receptors was excluded. Since ADPβS also activates P2Y13 receptors, the contribution of microglial P2Y13 receptors to prevent the proliferative effect of ADPβS in co-cultures was investigated. The results obtained indicate that P2Y13 receptors are low expressed in astrocytes and mainly expressed in microglia. Furthermore, in co-cultures, ADPβS induced astroglial proliferation in the presence of the selective P2Y13 antagonist MRS 2211 (3 μM and of the selective P2Y12 antagonist AR-C66096 (0.1 μM, suggesting that activation of microglial P2Y12 and P2Y13 receptors may induce the release of messengers that inhibit astroglial proliferation mediated by P2Y1,12 receptors. In this microglia-astrocyte paracrine communication, P2Y12 receptors exert opposite effects in astroglial proliferation as a result of its cellular localization: cooperating in astrocytes with P2Y1 receptors to directly stimulate proliferation and in

  14. The liver taxis of receptor mediated lactosaminated human growth hormone

    International Nuclear Information System (INIS)

    Chen Zelian; Shi Lin; Li Tongling; Pang Qijie; He Juying; Guan Changtian

    2002-01-01

    Radiography imaging is used to assess liver taxis mechanism of anti-dwarfism drug lactosaminated human growth hormone (L-rhGH). Both L-rhGH and rhGH labelled with 131 I are used to study their biodistribution in animals (including rabbits, cocks and rats). The results show that L-rhGH is of specific hepatic targeting property, and the maximum hepatic concentration rate is 76.8%, which is two times of rhGH. Its hepatic binding is receptor mediated

  15. Down-regulation of histamine-induced endothelial cell activation as potential anti-atherosclerotic activity of peptides from Spirulina maxima.

    Science.gov (United States)

    Vo, Thanh-Sang; Kim, Se-Kwon

    2013-10-09

    Histamine, a potent inflammatory mediator, has been known to cause the pathogenesis of atherosclerosis. In this sense, two bioactive peptides P1 (LDAVNR; 686Da) and P2 (MMLDF; 655Da) purified from gastric enzymatic hydrolysate of Spirulina maxima were examined for their protective effects against early atherosclerotic responses induced by histamine in EA.hy926 endothelial cells. Interestingly, both P1 and P2 exhibited inhibitory activities on the production and expression of IL-6 and MCP-1. Furthermore, P1 and P2 inhibited the production of adhesion molecules including P-selectin and E-selectin, and thus reducing in vitro cell adhesion of monocyte onto endothelial cells. In addition, the production of intracellular reactive oxygen species was observed to reduce in the presence of P1 or P2. Notably, the inhibitory activities of P1 and P2 were found due to down-regulating Egr-1 expression via histamine receptor and PKCδ-dependent MAPKs activation pathway. These results suggest that peptides P1 and P2 from S. maxima are effective to suppress histamine-induced endothelial cell activation that may contribute to the prevention of early atherosclerosis. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Histamine release from cord blood basophils

    DEFF Research Database (Denmark)

    Nielsen, Bent Windelborg; Damsgaard, Tine Engberg; Herlin, Troels

    1990-01-01

    The histamine release (HR) after challenge with anti-IgE, concanavalin A, N-formyl-met-leu-phe and the calcium ionophore A23187 from 97 cord blood samples was determined by a microfiber-based assay. Maximum HR with anti-IgE showed great inter-individual variation (median: 20.5; range: 1-104 ng...... of less than 0.5 IU/ml, although sensitivity to anti-IgE was universally increased. Preincubation with pharmacologic agents modulating the IgE-mediated HR produced effects generally similar to previous findings in adult blood. However, the effects of inhibiting the cyclooxygenase pathway in cord blood...

  17. Involvement of prostaglandins and histamine in nickel wire-induced acute inflammation in mice.

    Science.gov (United States)

    Hirasawa, Noriyasu; Goi, Yoshiaki; Tanaka, Rina; Ishihara, Kenji; Ohtsu, Hiroshi; Ohuchi, Kazuo

    2010-06-15

    The irritancy of Nickel (Ni) ions has been well documented clinically. However, the chemical mediators involved in the acute inflammation induced by solid Ni are not fully understood. We used the Ni wire-implantation model in mice and examined roles of prostaglandins and histamine in plasma leakage in the acute phase. The subcutaneous implantation of a Ni wire into the back of mice induced plasma leakage from 8 to 24 h and tissue necrosis around the wire at 3 days, whereas the implantation of an aluminum wire induced no such inflammatory responses. An increase in the mRNA for cyclooxygenase (COX)-2 and HDC in cells around the Ni wire was detected 4 h after the implantation. The leakage of plasma at 8 h was inhibited by indomethacin in a dose-dependent manner. Dexamethasone and the p38 MAP kinase inhibitor SB203580 also inhibited the exudation of plasma consistent with the inhibition of the expression of COX-2 mRNA. Furthermore, plasma leakage was partially but siginificantly reduced in histamine H1 receptor knockout mice and histidine decarboxylase (HDC) knockout mice but not in H2 receptor knockout mice. These results suggested that the Ni ions released from the wire induced the expression of COX-2 and HDC, resulting in an increase in vascular permeability during the acute phase of inflammation. (c) 2009 Wiley Periodicals, Inc.

  18. Protease activated receptors (PARS) mediation in gyroxin biological activity

    International Nuclear Information System (INIS)

    Silva, Jose Alberto Alves da

    2009-01-01

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH 2 , respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  19. Effect of ARA9 on dioxin receptor mediated transcription

    International Nuclear Information System (INIS)

    Lees, M.J.; Whitelaw, M.L.

    2002-01-01

    The dioxin (Aryl hydrocarbon) receptor (DR) is a unique bHLH transcription factor which is activated by binding of planar aromatic hydrocarbons typified by dioxin (TCDD). The active receptor is key to metabolism of aryl hydrocarbon xenobiotics by being a potent inducer of CYP1A1 gene activity. Chlorinated dioxins are inert to metabolism and initiate multifarious toxicities, including potent tumour promotion. These ill-effects are mediated by the activated DR and we are studying the mechanisms by which the ligand binding domain of the DR controls activity of the protein. The DR ligand binding domain resides within a PAS (Per/Arnt/Sim homology) region which is contiguous with the bHLH. The latent bHLH/PAS dioxin receptor (DR) is found in the cytoplasm of most mammalian cell types in a complex with heat shock protein 90, a novel immunophilin like protein termed ARA9/XAP2/AIP, and the co-chaperone p23. Here we use antisense ARA9 constructs to reveal that in the absence of ARA9, the DR is unable to form a transcriptionally active complex. Co-expression of antisense ARA9 with a form of the DR which is constitutively targeted to the nucleus leads to dramatically decreased levels of the nuclear DR protein, implying that ARA9 may function beyond its currently proposed role in cytoplasmic retention of the latent DR

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

    DEFF Research Database (Denmark)

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

    1996-01-01

    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......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.......0 (range 176.0-910.0) nmol/l in whole blood and 475.0 (range 360.0-1560.0) nmol/l in plasma-reduced whole blood, while it was undetectable in SAGM blood. Spontaneous histamine release increased in a time-dependent manner from a median of 6.7 (range 2.2-17.4) nmol/l at the time of storage to 175.0 (range 33...

  1. Toll-like receptor 9 mediated responses in cardiac fibroblasts.

    Directory of Open Access Journals (Sweden)

    Ingrid Kristine Ohm

    Full Text Available Altered cardiac Toll-like receptor 9 (TLR9 signaling is important in several experimental cardiovascular disorders. These studies have predominantly focused on cardiac myocytes or the heart as a whole. Cardiac fibroblasts have recently been attributed increasing significance in mediating inflammatory signaling. However, putative TLR9-signaling through cardiac fibroblasts remains non-investigated. Thus, our aim was to explore TLR9-signaling in cardiac fibroblasts and investigate the consequence of such receptor activity on classical cardiac fibroblast cellular functions. Cultivated murine cardiac fibroblasts were stimulated with different TLR9 agonists (CpG A, B and C and assayed for the secretion of inflammatory cytokines (tumor necrosis factor α [TNFα], CXCL2 and interferon α/β. Expression of functional cardiac fibroblast TLR9 was proven as stimulation with CpG B and -C caused significant CXCL2 and TNFα-release. These responses were TLR9-specific as complete inhibition of receptor-stimulated responses was achieved by co-treatment with a TLR9-antagonist (ODN 2088 or chloroquine diphosphate. TLR9-stimulated responses were also found more potent in cardiac fibroblasts when compared with classical innate immune cells. Stimulation of cardiac fibroblasts TLR9 was also found to attenuate migration and proliferation, but did not influence myofibroblast differentiation in vitro. Finally, results from in vivo TLR9-stimulation with subsequent fractionation of specific cardiac cell-types (cardiac myocytes, CD45+ cells, CD31+ cells and cardiac fibroblast-enriched cell-fractions corroborated our in vitro data and provided evidence of differentiated cell-specific cardiac responses. Thus, we conclude that cardiac fibroblast may constitute a significant TLR9 responder cell within the myocardium and, further, that such receptor activity may impact important cardiac fibroblast cellular functions.

  2. Milrinone attenuates thromboxane receptor-mediated hyperresponsiveness in hypoxic pulmonary arterial myocytes.

    Science.gov (United States)

    Santhosh, K T; Elkhateeb, O; Nolette, N; Outbih, O; Halayko, A J; Dakshinamurti, S

    2011-07-01

    Neonatal pulmonary hypertension (PPHN) is characterized by pulmonary vasoconstriction, due in part to dysregulation of the thromboxane prostanoid (TP) receptor. Hypoxia induces TP receptor-mediated hyperresponsiveness, whereas serine phosphorylation mediates desensitization of TP receptors. We hypothesized that prostacyclin (IP) receptor activity induces TP receptor phosphorylation and decreases ligand affinity; that TP receptor sensitization in hypoxic myocytes is due to IP receptor inactivation; and that this would be reversible by the cAMP-specific phosphodiesterase inhibitor milrinone. We examined functional regulation of TP receptors by serine phosphorylation and effects of IP receptor stimulation and protein kinase A (PKA) activity on TP receptor sensitivity in myocytes from neonatal porcine resistance pulmonary arteries after 72 h hypoxia in vitro. Ca(2+) response curves to U46619 (TP receptor agonist) were determined in hypoxic and normoxic myocytes incubated with or without iloprost (IP receptor agonist), forskolin (adenylyl cyclase activator), H8 (PKA inhibitor) or milrinone. TP and IP receptor saturation binding kinetics were measured in presence of iloprost or 8-bromo-cAMP. Ligand affinity for TP receptors was normalized in vitro by IP receptor signalling intermediates. However, IP receptor affinity was compromised in hypoxic myocytes, decreasing cAMP production. Milrinone normalized TP receptor sensitivity in hypoxic myocytes by restoring PKA-mediated regulatory TP receptor phosphorylation. TP receptor sensitivity and EC(50) for TP receptor agonists was regulated by PKA, as TP receptor serine phosphorylation by PKA down-regulated Ca(2+) mobilization. Hypoxia decreased IP receptor activity and cAMP generation, inducing TP receptor hyperresponsiveness, which was reversed by milrinone. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

  3. Ligand Receptor-Mediated Regulation of Growth in Plants.

    Science.gov (United States)

    Haruta, Miyoshi; Sussman, Michael R

    2017-01-01

    Growth and development of multicellular organisms are coordinately regulated by various signaling pathways involving the communication of inter- and intracellular components. To form the appropriate body patterns, cellular growth and development are modulated by either stimulating or inhibiting these pathways. Hormones and second messengers help to mediate the initiation and/or interaction of the various signaling pathways in all complex multicellular eukaryotes. In plants, hormones include small organic molecules, as well as larger peptides and small proteins, which, as in animals, act as ligands and interact with receptor proteins to trigger rapid biochemical changes and induce the intracellular transcriptional and long-term physiological responses. During the past two decades, the availability of genetic and genomic resources in the model plant species, Arabidopsis thaliana, has greatly helped in the discovery of plant hormone receptors and the components of signal transduction pathways and mechanisms used by these immobile but highly complex organisms. Recently, it has been shown that two of the most important plant hormones, auxin and abscisic acid (ABA), act through signaling pathways that have not yet been recognized in animals. For example, auxins stimulate cell elongation by bringing negatively acting transcriptional repressor proteins to the proteasome to be degraded, thus unleashing the gene expression program required for increasing cell size. The "dormancy" inducing hormone, ABA, binds to soluble receptor proteins and inhibits a specific class of protein phosphatases (PP2C), which activates phosphorylation signaling leading to transcriptional changes needed for the desiccation of the seeds prior to entering dormancy. While these two hormone receptors have no known animal counterparts, there are also many similarities between animal and plant signaling pathways. For example, in plants, the largest single gene family in the genome is the protein kinase

  4. Measurement of histamine release from human lung tissue ex vivo by microdialysis technique

    DEFF Research Database (Denmark)

    Nissen, Dan; Petersen, Lars Jelstrup; Nolte, H

    1998-01-01

    OBJECTIVE AND DESIGN: Currently no method is available for measurement of mediator release from intact human lung. In this study, a microdialysis technique was used to measure histamine release from mast cells in human lung tissue ex vivo. MATERIAL: Microdialysis fibers of 216 microm were inserted...... responses were observed but data could be reproduced within individual donors. Monocyte chemoattractant protein-1, a potent basophil secretagogue, did not induce histamine release in lung tissue which indicated mast cells to be the histamine source. Substance P did not release histamine in the lung tissue....... CONCLUSIONS: The microdialysis technique allowed measurements of histamine release from mast cells in intact lung ex vivo. The method may prove useful since a number of experiments can be performed in a few hours in intact lung tissue without any dispersion or enzymatic treatment....

  5. 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; Horner, Richard L

    2015-10-07

    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:TASK(f/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:TASK(f/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. Attentive states and cognitive function are associated with the generation of γ EEG activity. Basal forebrain

  6. Receptor-mediated endocytosis of trichosanthin in choriocarcinoma cells

    International Nuclear Information System (INIS)

    Chan, W.Y.; Huang Hai; Tam, S.-C.

    2003-01-01

    Trichosanthin (TCS) is a ribosome inactivating protein (RIP). It is generally believed that its many biological activities act through inhibition of ribosomes resulting in a decrease in protein synthesis. It has been hypothesized that the rate of entry of TCS into cells to reach ribosomes is an important factor in determining its biological activity. To prove this hypothesis, we have mapped out and compared the intracellular routing of TCS in two cell lines, namely the choriocarcinoma JAR cell line, which is known to be highly sensitive to the toxic effects of TCS, and the hepatoma H35 cell line, to which TCS shows minimal toxicity. Results from laser scanning confocal microscopy indicated that fluorescein isothiocyanate labeled TCS quickly accumulated inside JAR cells within 4 h of incubation while only a low level of fluorescent signals was detected in H35 cells during the same period of time. When TCS was conjugated with gold particles (Au) and its intracellular locations were traced with a transmission electron microscope, it was found that most of TCS were bound to coated pits on the JAR cell surface and were rapidly internalized within an hour. By 4 h, TCS reached almost every cytoplasmic region including ribosomes, and the JAR cell began to degenerate. In H35 cells, however, the binding of TCS to coated pits was not observed, but instead, a small amount of TCS was found to penetrate the cell non-specifically by direct diffusion across the cell membrane. Our observations suggest that most of TCS enter JAR cells via a specific receptor mediated pathway, which allows a swift transport of TCS across the membrane and a rapid accumulation of intracellular TCS, while in H35 cells, TCS takes a slow and non-specific route. The receptor-mediated uptake together with the specific intracellular routing of TCS may partly account for the differential vulnerability of the choriocarcinoma cell line towards the toxicity of TCS

  7. Discoidin Domain Receptor 1 Mediates Myosin-Dependent Collagen Contraction

    Directory of Open Access Journals (Sweden)

    Nuno M. Coelho

    2017-02-01

    Full Text Available Discoidin domain receptor 1 (DDR1 is a tyrosine kinase collagen adhesion receptor that mediates cell migration through association with non-muscle myosin IIA (NMIIA. Because DDR1 is implicated in cancer fibrosis, we hypothesized that DDR1 interacts with NMIIA to enable collagen compaction by traction forces. Mechanical splinting of rat dermal wounds increased DDR1 expression and collagen alignment. In periodontal ligament of DDR1 knockout mice, collagen mechanical reorganization was reduced >30%. Similarly, cultured cells with DDR1 knockdown or expressing kinase-deficient DDR1d showed 50% reduction of aligned collagen. Tractional remodeling of collagen was dependent on DDR1 clustering, activation, and interaction of the DDR1 C-terminal kinase domain with NMIIA filaments. Collagen remodeling by traction forces, DDR1 tyrosine phosphorylation, and myosin light chain phosphorylation were increased on stiff versus soft substrates. Thus, DDR1 clustering, activation, and interaction with NMIIA filaments enhance the collagen tractional remodeling that is important for collagen compaction in fibrosis.

  8. Somatostatin receptor-mediated imaging and therapy: basic science, current knowledge, limitations and future perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Breeman, W.A.P.; Jong, M. de; Kwekkeboom, D.J.; Valkema, R.; Bakker, W.H.; Kooij, P.P.M. [Dept. of Nuclear Medicine, Erasmus Medical Centre Rotterdam (Netherlands); Visser, T.J. [Dept. of Internal Medicine, Erasmus Medical Centre Rotterdam (Netherlands); Krenning, E.P. [Dept. of Nuclear Medicine, Erasmus Medical Centre Rotterdam (Netherlands); Dept. of Internal Medicine, Erasmus Medical Centre Rotterdam (Netherlands)

    2001-09-01

    In vivo somatostatin receptor-mediated scintigraphy has proven to be a valuable method for the visualisation of neuroendocrine tumours and their metastases. A new application is the use of radiolabelled analogues for somatostatin receptor-mediated therapy. This paper presents a review on the basic science, historical background and current knowledge of somatostatin receptor subtypes and their expression in neuroendocrine tumours. New somatostatin analogues, new chelators, ''new'' radionuclides and combinations thereof are also discussed. Due attention is given to limitations and future perspectives of somatostatin receptor-mediated imaging and therapy. (orig.)

  9. Somatostatin receptor-mediated imaging and therapy: basic science, current knowledge, limitations and future perspectives

    International Nuclear Information System (INIS)

    Breeman, W.A.P.; Jong, M. de; Kwekkeboom, D.J.; Valkema, R.; Bakker, W.H.; Kooij, P.P.M.; Visser, T.J.; Krenning, E.P.

    2001-01-01

    In vivo somatostatin receptor-mediated scintigraphy has proven to be a valuable method for the visualisation of neuroendocrine tumours and their metastases. A new application is the use of radiolabelled analogues for somatostatin receptor-mediated therapy. This paper presents a review on the basic science, historical background and current knowledge of somatostatin receptor subtypes and their expression in neuroendocrine tumours. New somatostatin analogues, new chelators, ''new'' radionuclides and combinations thereof are also discussed. Due attention is given to limitations and future perspectives of somatostatin receptor-mediated imaging and therapy. (orig.)

  10. The histamine content of oriental foods.

    Science.gov (United States)

    Chin, K W; Garriga, M M; Metcalfe, D D

    1989-05-01

    Several of the symptoms of scombroid poisoning (i.e. histamine toxicity) resemble those observed in people suffering from Chinese restaurant syndrome. Therefore, the histamine content of representative Chinese cuisine, which included 31 common dishes, 12 condiments and 12 basic ingredients from several sources, was measured using a sensitive and specific radioenzymatic assay. A further enzymatic procedure involving diamine oxidase was used to verify that the substance measured was histamine. A total of 184 assays were performed on 57 samples in the study. High levels of histamine were found in the cheeses, which were used as positive controls (863.6 micrograms histamine/g blue cheese and 107.4 micrograms histamine/g Parmesan cheese), and in some common condiments, including tamari (2392.2 micrograms histamine/g sample) and one brand of soy sauce (220.4 micrograms histamine/g sample). The histamine content of four condiments and three common dishes was over 10 micrograms histamine/g sample, while four condiments and 16 common dishes contained less than 1 microgram histamine/g sample. Calculations involving representative amounts of food that can be consumed at a typical oriental meal suggest that, in some cases, histamine intake may approach toxic levels. The results are discussed with regard to the possible role of histamine in reactions associated with restaurant meals.

  11. ZINC-INDUCED EGF RECEPTOR SIGNALING REQUIRES SRC-MEDIATED PHOSPHORYLATION OF THE EGF RECEPTOR ON TYROSINE 845 (Y845)

    Science.gov (United States)

    ZINC-INDUCED EGF RECEPTOR SIGNALING REQUIRES Src-MEDIATED PHOSPHORYLATION OF THE EGF RECEPTOR ON TYROSINE 845 (Y845)Weidong Wu1, Lee M. Graves2, Gordon N. Gill3 and James M. Samet4 1Center for Environmental Medicine and Lung Biology; 2Department of Pharmacology, University o...

  12. Lactobacillus reuteri-specific immunoregulatory gene rsiR modulates histamine production and immunomodulation by Lactobacillus reuteri.

    Science.gov (United States)

    Hemarajata, P; Gao, C; Pflughoeft, K J; Thomas, C M; Saulnier, D M; Spinler, J K; Versalovic, J

    2013-12-01

    Human microbiome-derived strains of Lactobacillus reuteri potently suppress proinflammatory cytokines like human tumor necrosis factor (TNF) by converting the amino acid l-histidine to the biogenic amine histamine. Histamine suppresses mitogen-activated protein (MAP) kinase activation and cytokine production by signaling via histamine receptor type 2 (H2) on myeloid cells. Investigations of the gene expression profiles of immunomodulatory L. reuteri ATCC PTA 6475 highlighted numerous genes that were highly expressed during the stationary phase of growth, when TNF suppression is most potent. One such gene was found to be a regulator of genes involved in histidine-histamine metabolism by this probiotic species. During the course of these studies, this gene was renamed the Lactobacillus reuteri-specific immunoregulatory (rsiR) gene. The rsiR gene is essential for human TNF suppression by L. reuteri and expression of the histidine decarboxylase (hdc) gene cluster on the L. reuteri chromosome. Inactivation of rsiR resulted in diminished TNF suppression in vitro and reduced anti-inflammatory effects in vivo in a trinitrobenzene sulfonic acid (TNBS)-induced mouse model of acute colitis. A L. reuteri strain lacking an intact rsiR gene was unable to suppress colitis and resulted in greater concentrations of serum amyloid A (SAA) in the bloodstream of affected animals. The PhdcAB promoter region targeted by rsiR was defined by reporter gene experiments. These studies support the presence of a regulatory gene, rsiR, which modulates the expression of a gene cluster known to mediate immunoregulation by probiotics at the transcriptional level. These findings may point the way toward new strategies for controlling gene expression in probiotics by dietary interventions or microbiome manipulation.

  13. Secretory phospholipase A2-mediated neuronal cell death involves glutamate ionotropic receptors

    DEFF Research Database (Denmark)

    Kolko, Miriam; de Turco, Elena B; Diemer, Nils Henrik

    2002-01-01

    To define the significance of glutamate ionotropic receptors in sPLA -mediated neuronal cell death we used the NMDA receptor antagonist MK-801 and the AMPA receptor antagonist PNQX. In primary neuronal cell cultures both MK-801 and PNQX inhibited sPLA - and glutamate-induced neuronal death. [ H...

  14. Effects of histamine and 5-hydroxytryptamine on the growth rate of xenografted human bronchogenic carcinomas.

    Science.gov (United States)

    Sheehan, P F; Baker, T; Tutton, P J; Barkla, D H

    1996-01-01

    1. The influence of histamine and 5-hydroxytryptamine (5-HT) antagonists and agonists on the volume doubling times (Td) of human bronchogenic carcinomas propagated as s.c. xenografts in immunosuppressed mice was examined. 2. The H2-receptor antagonists, cimetidine and ranitidine, increased Td. 3. Treatment with the H2-receptor agonist, 4-methyl histamine, had no effect on Td. 4. Co-administration of 4-methyl histamine and cimetidine abolished the effects of cimetidine. 5. The 5-HT2-receptor antagonists, cinanserin and ketanserin, both increased Td. 6. Treatment with the 5-HT1/2-receptor agonist quipazine (0.1 mg/kg, reflecting 5-HT2 agonist activity) decreased Td, while a higher dose (10.0 mg/kg) had no effect. 7. The 5-HT1/2-receptor antagonist, methiothepin, decreased Td. 8. The 5-HT uptake inhibitor, fluoxetine, increased Td in one tumour line but not in another, while the 5-HT releaser/depletor, fenfluramine, increased Td. 9. Histamine may stimulate tumour growth through the histamine H2-receptor, while the dominant effect of 5-HT is 5-HT1-receptor inhibition. 10. Tumour growth in some bronchogenic carcinomas may involve 5-HT uptake mechanisms.

  15. Redox regulation of mast cell histamine release in thioredoxin-1 (TRX) transgenic mice.

    Science.gov (United States)

    Son, Aoi; Nakamura, Hajime; Kondo, Norihiko; Matsuo, Yoshiyuki; Liu, Wenrui; Oka, Shin-ichi; Ishii, Yasuyuki; Yodoi, Junji

    2006-02-01

    Thioredoxin-1 (TRX) is a stress-inducible redox-regulatory protein with antioxidative and anti-inflammatory effects. Here we show that the release of histamine from mast cells elicited by cross-linking of high-affinity receptor for IgE (FcepsilonRI) was significantly suppressed in TRX transgenic (TRX-tg) mice compared to wild type (WT) mice. Intracellular reactive oxygen species (ROS) of mast cells stimulated by IgE and antigen was also reduced in TRX-tg mice compared to WT mice. Whereas there was no difference in the production of cytokines (IL-6 and TNF-alpha) from mast cells in response to 2,4-dinitrophenylated bovine serum albumin (DNP-BSA) stimulation in TRX-tg and WT mice. Immunological status of TRX-tg mice inclined to T helper (Th) 2 dominant in primary immune response, although there was no difference in the population of dendritic cells (DCs) and regulatory T cells. We conclude that the histamine release from mast cells in TRX-tg mice is suppressed by inhibition of ROS generation. As ROS are involved in mast cell activation and facilitate mediator release, TRX may be a key signaling molecule regulating the early events in the IgE signaling in mast cells and the allergic inflammation.

  16. Sickle erythrocytes enhance phenylephrine and histamine ...

    African Journals Online (AJOL)

    Sickle erythrocytes enhance phenylephrine and histamine contractions of isolated rabbit carotid arteries. ... enhancement of histamine contractions, compared with phenylephrine (in AS and SS), suggests a possible role for histamine in the increased vascular tone and vaso-occlusive crisis in sickle cell disease.

  17. Erythropoietin's Beta Common Receptor Mediates Neuroprotection in Spinal Cord Neurons.

    Science.gov (United States)

    Foley, Lisa S; Fullerton, David A; Mares, Joshua; Sungelo, Mitchell; Weyant, Michael J; Cleveland, Joseph C; Reece, T Brett

    2017-12-01

    Paraplegia from spinal cord ischemia-reperfusion (SCIR) remains an elusive and devastating complication of complex aortic operations. Erythropoietin (EPO) attenuates this injury in models of SCIR. Upregulation of the EPO beta common receptor (βcR) is associated with reduced damage in models of neural injury. The purpose of this study was to examine whether EPO-mediated neuroprotection was dependent on βcR expression. We hypothesized that spinal cord neurons subjected to oxygen-glucose deprivation would mimic SCIR injury in aortic surgery and EPO treatment attenuates this injury in a βcR-dependent fashion. Lentiviral vectors with βcR knockdown sequences were tested on neuron cell cultures. The virus with greatest βcR knockdown was selected. Spinal cord neurons from perinatal wild-type mice were harvested and cultured to maturity. They were treated with knockdown or nonsense virus and transduced cells were selected. Three groups (βcR knockdown virus, nonsense control virus, no virus control; n = 8 each) were subjected to 1 hour of oxygen-glucose deprivation. Viability was assessed. βcR expression was quantified by immunoblot. EPO preserved neuronal viability after oxygen-glucose deprivation (0.82 ± 0.04 versus 0.61 ± 0.01; p neuron preservation was similar in the nonsense virus and control mice (0.82 ± 0.04 versus 0.80 ± 0.05; p = 0.77). EPO neuron preservation was lost in βcR knockdown mice compared with nonsense control mice (0.46 ± 0.03 versus 0.80 ± 0.05; p neuronal loss after oxygen-glucose deprivation in a βcR-dependent fashion. This receptor holds immense clinical promise as a target for pharmacotherapies treating spinal cord ischemic injury. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  18. Thyrotropin modulates receptor-mediated processing of the atrial natriuretic peptide receptor in cultured thyroid cells

    International Nuclear Information System (INIS)

    Tseng, Y.L.; Burman, K.D.; Lahiri, S.; Abdelrahim, M.M.; D'Avis, J.C.; Wartofsky, L.

    1991-01-01

    In a prior study of atrial natriuretic peptide (ANP) binding to cultured thyroid cells, we reported that at 4 C, more than 95% of bound ANP is recovered on cell membranes, with negligible ANP internalization observed. Since ANP binding was inhibited by TSH, we have further studied TSH effects on postbinding ANP processing to determine whether this phenomenon reflects enhanced endocytosis of the ANP-receptor complex. An ANP chase study was initiated by binding [125I] ANP to thyroid cells at 4 C for 2 h, followed by incubation at 37 C. ANP processing was then traced by following 125I activity at various time intervals in three fractions: cell surface membranes, incubation medium, and inside the cells. Radioactivity released into medium represented processed ANP rather than ANP dissociated from surface membranes, since prebound [125I]ANP could not be competitively dissociated by a high concentration of ANP (1 mumol/L) at 37 C. Chase study results showed that prebound ANP quickly disappeared from cell membranes down to 34% by 30 min. Internalized ANP peaked at 10 min, with 21% of initial prebound ANP found inside the cells. At the same time, radioactivity recovered in incubation medium sharply increased between 10-30 min from 8% to 52%. Preincubation of cells with chloroquine (which blocks degradation of the ANP-receptor complex by inhibiting lysosomal hydrolase) caused a 146% increase in internalized [125I]ANP by 30 min (39% compared to 15% control), while medium radioactivity decreased from 52% to 16%, suggesting that processing of the receptor complex is mediated via lysosomal enzymes. In chase studies employing cells pretreated with chloroquine, TSH stimulated the internalization rate of ANP-receptor complex. By 30 min, TSH significantly reduced the membrane-bound ANP, and the decrease was inversely correlated to the increase in internalized radioactivity

  19. Histamine, mast cells, and the enteric nervous system in the irritable bowel syndrome, enteritis, and food allergies

    OpenAIRE

    Wood, J D

    2006-01-01

    There is altered expression of histamine H1 and H2 receptor subtypes in mucosal biopsies from the terminal ileum and large intestine of patients with symptoms of food allergy and/or irritable bowel syndrome

  20. Selectivity and specificity of sphingosine-1-phosphate receptor ligands: caveats and critical thinking in characterizing receptor-mediated effects.

    Science.gov (United States)

    Salomone, Salvatore; Waeber, Christian

    2011-01-01

    Receptors for sphingosine-1-phosphate (S1P) have been identified only recently. Their medicinal chemistry is therefore still in its infancy, and few selective agonists or antagonists are available. Furthermore, the selectivity of S1P receptor agonists or antagonists is not well established. JTE-013 and BML-241 (also known as CAY10444), used extensively as specific S1P(2) and S1P(3) receptors antagonists respectively, are cases in point. When analyzing S1P-induced vasoconstriction in mouse basilar artery, we observed that JTE-013 inhibited not only the effect of S1P, but also the effect of U46619, endothelin-1 or high KCl; JTE-013 strongly inhibited responses to S1P in S1P(2) receptor knockout mice. Similarly, BML-241 has been shown to inhibit increases in intracellular Ca(2+) concentration via P(2) receptor or α(1A)-adrenoceptor stimulation and α(1A)-adrenoceptor-mediated contraction of rat mesenteric artery, while it did not affect S1P(3)-mediated decrease of forskolin-induced cyclic AMP accumulation. Another putative S1P(1/3) receptor antagonist, VPC23019, does not inhibit S1P(3)-mediated vasoconstriction. With these examples in mind, we discuss caveats about relying on available pharmacological tools to characterize receptor subtypes.

  1. Selectivity and specificity of sphingosine-1-phosphate receptor ligands: caveats and critical thinking in characterizing receptor-mediated effects

    Directory of Open Access Journals (Sweden)

    Christian eWaeber

    2011-02-01

    Full Text Available Receptors for sphingosine-1-phosphate (S1P have been identified only recently. Their medicinal chemistry is therefore still in its infancy, and few selective agonists or antagonists are available. Furthermore, the selectivity of S1P receptor agonists or antagonists is not well established. JTE-013 and BML-241 (also known as CAY10444, used extensively as specific S1P2 and S1P3 receptors antagonists respectively, are cases in point. When analyzing S1P-induced vasoconstriction in mouse basilar artery, we observed that JTE-013 inhibited not only the effect of S1P, but also the effect of U46619, endothelin-1 or high KCl; JTE-013 strongly inhibited responses to S1P in S1P2 receptor knockout mice. Similarly, BML-241 has been shown to inhibit increases in intracellular Ca2+ concentration via P2 receptor or α1A-adrenoceptor stimulation and α1A-adrenoceptor-mediated contraction of rat mesenteric artery, while it did not affect S1P3-mediated decrease of forskolin-induced cyclic AMP accumulation. Another putative S1P1/3 receptor antagonist, VPC23019, does not inhibit S1P3-mediated vasoconstriction. With these examples in mind, we discuss caveats about relying on available pharmacological tools to characterize receptor subtypes.

  2. 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 ...... conclude that oral administration of enterosoluble capsules is an easy and appropriate method for intestinal histamine challenge. Fast and histamine-restrictive diets are not necessary, but subjects should record unexpected responses in a food and symptom diary.......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...... all other intervals did not differ significantly between the two challenge regimens. Fast (water only) and histamine-restrictive diet versus non-restrictive diet did not affect the urinary MIAA. MIAA was significantly higher overall during the first 24 h after challenge than in any other fraction. We...

  3. Histamine 50-skin-prick test: a tool to diagnose histamine intolerance.

    Science.gov (United States)

    Kofler, Lukas; Ulmer, Hanno; Kofler, Heinz

    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 pruritus. Objective. Diagnosis of histamine intolerance until now is based on case history; neither a validated questionnaire nor a routine test is available. It was the aim of this trial to evaluate the usefullness of a prick-test for the diagnosis of histamine intolerance. Methods. Prick-testing with 1% histamine solution and wheal size-measurement to assess the relation between the wheal in prick-test, read after 20 to 50 minutes, as sign of slowed histamine degradation as well as history and symptoms of histamine intolerance. Results. Besides a pretest with 17 patients with HIT we investigated 156 persons (81 with HIT, 75 controls): 64 out of 81 with histamine intolerance(HIT), but only 14 out of 75 persons from the control-group presented with a histamine wheal ≥3 mm after 50 minutes (P < .0001). Conclusion and Clinical Relevance. Histamine-50 skin-prickt-test offers a simple tool with relevance.

  4. Cross-talk between an activator of nuclear receptors-mediated transcription and the D1 dopamine receptor signaling pathway.

    Science.gov (United States)

    Schmidt, Azriel; Vogel, Robert; Rutledge, Su Jane; Opas, Evan E; Rodan, Gideon A; Friedman, Eitan

    2005-03-01

    Nuclear receptors are transcription factors that usually interact, in a ligand-dependent manner, with specific DNA sequences located within promoters of target genes. The nuclear receptors can also be controlled in a ligand-independent manner via the action of membrane receptors and cellular signaling pathways. 5-Tetradecyloxy-2-furancarboxylic acid (TOFA) was shown to stimulate transcription from the MMTV promoter via chimeric receptors that consist of the DNA binding domain of GR and the ligand binding regions of the PPARbeta or LXRbeta nuclear receptors (GR/PPARbeta and GR/LXRbeta). TOFA and hydroxycholesterols also modulate transcription from NF-kappaB- and AP-1-controlled reporter genes and induce neurite differentiation in PC12 cells. In CV-1 cells that express D(1) dopamine receptors, D(1) dopamine receptor stimulation was found to inhibit TOFA-stimulated transcription from the MMTV promoter that is under the control of chimeric GR/PPARbeta and GR/LXRbeta receptors. Treatment with the D(1) dopamine receptor antagonist, SCH23390, prevented dopamine-mediated suppression of transcription, and by itself increased transcription controlled by GR/LXRbeta. Furthermore, combined treatment of CV-1 cells with TOFA and SCH23390 increased transcription controlled by the GR/LXRbeta chimeric receptor synergistically. The significance of this in vitro synergy was demonstrated in vivo, by the observation that SCH23390 (but not haloperidol)-mediated catalepsy in rats was potentiated by TOFA, thus showing that an agent that mimics the in vitro activities of compounds that activate members of the LXR and PPAR receptor families can influence D1 dopamine receptor elicited responses.

  5. The Measles Virus Receptor SLAMF1 Can Mediate Particle Endocytosis.

    Science.gov (United States)

    Gonçalves-Carneiro, Daniel; McKeating, Jane A; Bailey, Dalan

    2017-04-01

    The signaling lymphocyte activation molecule F1 (SLAMF1) is both a microbial sensor and entry receptor for measles virus (MeV). Herein, we describe a new role for SLAMF1 to mediate MeV endocytosis that is in contrast with the alternative, and generally accepted, model that MeV genome enters cells only after fusion at the cell surface. We demonstrated that MeV engagement of SLAMF1 induces dramatic but transient morphological changes, most prominently in the formation of membrane blebs, which were shown to colocalize with incoming viral particles, and rearrangement of the actin cytoskeleton in infected cells. MeV infection was dependent on these dynamic cytoskeletal changes as well as fluid uptake through a macropinocytosis-like pathway as chemical inhibition of these processes inhibited entry. Moreover, we identified a role for the RhoA-ROCK-myosin II signaling axis in this MeV internalization process, highlighting a novel role for this recently characterized pathway in virus entry. Our study shows that MeV can hijack a microbial sensor normally involved in bacterial phagocytosis to drive endocytosis using a complex pathway that shares features with canonical viral macropinocytosis, phagocytosis, and mechanotransduction. This uptake pathway is specific to SLAMF1-positive cells and occurs within 60 min of viral attachment. Measles virus remains a significant cause of mortality in human populations, and this research sheds new light on the very first steps of infection of this important pathogen. IMPORTANCE Measles is a significant disease in humans and is estimated to have killed over 200 million people since records began. According to current World Health Organization statistics, it still kills over 100,000 people a year, mostly children in the developing world. The causative agent, measles virus, is a small enveloped RNA virus that infects a broad range of cells during infection. In particular, immune cells are infected via interactions between glycoproteins found

  6. Plant cell surface receptor-mediated signaling - a common theme amid diversity.

    Science.gov (United States)

    He, Yunxia; Zhou, Jinggeng; Shan, Libo; Meng, Xiangzong

    2018-01-29

    Sessile plants employ a diverse array of plasma membrane-bound receptors to perceive endogenous and exogenous signals for regulation of plant growth, development and immunity. These cell surface receptors include receptor-like kinases (RLKs) and receptor-like proteins (RLPs) that harbor different extracellular domains for perception of distinct ligands. Several RLK and RLP signaling pathways converge at the somatic embryogenesis receptor kinases (SERKs), which function as shared co-receptors. A repertoire of receptor-like cytoplasmic kinases (RLCKs) associate with the receptor complexes to relay intracellular signaling. Downstream of the receptor complexes, mitogen-activated protein kinase (MAPK) cascades are among the key signaling modules at which the signals converge, and these cascades regulate diverse cellular and physiological responses through phosphorylation of different downstream substrates. In this Review, we summarize the emerging common theme that underlies cell surface receptor-mediated signaling pathways in Arabidopsis thaliana : the dynamic association of RLKs and RLPs with specific co-receptors and RLCKs for signal transduction. We further discuss how signaling specificities are maintained through modules at which signals converge, with a focus on SERK-mediated receptor signaling. © 2018. Published by The Company of Biologists Ltd.

  7. Measuring histamine and cytokine release from basophils and mast cells

    DEFF Research Database (Denmark)

    Jensen, Bettina M; Falkencrone, Sidsel; Skov, Per S

    2014-01-01

    Basophils and mast cells are known for their capability to release both preformed and newly synthesized inflammatory mediators. In this chapter we describe how to stimulate and detect histamine released from basophils in whole blood, purified basophils, in vitro cultured mast cells, and in situ...... skin mast cells. We also give an example of an activation protocol for basophil and mast cell cytokine release and discuss approaches for cytokine detection....

  8. Pharmacological significance of the interplay between angiotensin receptors: MAS receptors as putative final mediators of the effects elicited by angiotensin AT1 receptors antagonists.

    Science.gov (United States)

    Pernomian, Larissa; Pernomian, Laena; Gomes, Mayara S; da Silva, Carlos H T P

    2015-12-15

    The interplay between angiotensin AT1 receptors and MAS receptors relies on several inward regulatory mechanisms from renin-angiotensin system (RAS) including the functional crosstalk between angiotensin II and angiotensin-(1-7), the competitive AT1 antagonism exhibited by angiotensin-(1-7), the antagonist feature assigned to AT1/MAS heterodimerization on AT1 signaling and the AT1-mediated downregulation of angiotensin-converting enzyme 2 (ACE2). Recently, such interplay has acquired an important significance to RAS Pharmacology since a few studies have supporting strong evidences that MAS receptors mediate the effects elicited by AT1 antagonists. The present Perspective provides an overview of the regulatory mechanisms involving AT1 and MAS receptors, their significance to RAS Pharmacology and the future directions on the interplay between angiotensin receptors. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Indian red scorpion venom-induced augmentation of cardio-respiratory reflexes and pulmonary edema involve the release of histamine.

    Science.gov (United States)

    Dutta, Abhaya; Deshpande, Shripad B

    2011-02-01

    Pulmonary edema is a consistent feature of Mesobuthus tamulus (MBT) envenomation. Kinins, prostaglandins and other inflammatory mediators are implicated in it. Since, histamine also increases capillary permeability, this study was undertaken to evaluate whether MBT venom utilizes histamine to produce pulmonary edema and augmentation of cardio-respiratory reflexes evoked by phenylbiguanide (PBG). Blood pressure, respiratory excursions and ECG were recorded in urethane anaesthetized adult rats. Injection of PBG (10 μg/kg) produced apnoea, hypotension and bradycardia and the responses were augmented after exposure to venom (100 μg/kg). There was increased pulmonary water content in these animals. Pretreatment with pheniramine maleate (H₁ antagonist, 3 mg/kg) blocked both venom-induced augmentation of PBG response and pulmonary edema. In another series, compound 48/80 (mast cell depletor) was treated for 4 days then the PBG responses were elicited as before. At the end of the experiments, mast cells were counted from the peritoneal fluid. The venom-induced pulmonary edema and the augmentation of PBG reflex were not observed in compound 48/80 treated animals. Further, mast cells in the peritoneal fluid were absent in this group as compared to vehicle treated group (29 ± 7.9 cells/mm³). These observations indicate that venom-induced pulmonary edema and augmentation of PBG reflexe are mediated through mast cells by involving H₁ receptors. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Ligand-mediated negative regulation of a chimeric transmembrane receptor tyrosine phosphatase

    DEFF Research Database (Denmark)

    Desai, D M; Sap, J; Schlessinger, J

    1993-01-01

    CD45, a transmembrane protein tyrosine phosphatase (PTPase), is required for TCR signaling. Multiple CD45 isoforms, differing in the extracellular domain, are expressed in a tissue- and activation-specific manner, suggesting an important function for this domain. We report that a chimeric protein...... that ligand-mediated regulation of receptor-PTPases may have mechanistic similarities with receptor tyrosine kinases....

  11. In vitro binding and receptor-mediated activity of terlipressin at vasopressin receptors V1 and V2.

    Science.gov (United States)

    Jamil, Khurram; Pappas, Stephen Chris; Devarakonda, Krishna R

    2018-01-01

    Terlipressin, a synthetic, systemic vasoconstrictor with selective activity at vasopressin-1 (V 1 ) receptors, is a pro-drug for the endogenous/natural porcine hormone [Lys 8 ]-vasopressin (LVP). We investigated binding and receptor-mediated cellular activities of terlipressin, LVP, and endogenous human hormone [Arg 8 ]-vasopressin (AVP) at V 1 and vasopressin-2 (V 2 ) receptors. Cell membrane homogenates of Chinese hamster ovary cells expressing human V 1 and V 2 receptors were used in competitive binding assays to measure receptor-binding activity. These cells were used in functional assays to measure receptor-mediated cellular activity of terlipressin, LVP, and AVP. Binding was measured by [ 3 H]AVP counts, and the activity was measured by fluorometric detection of intracellular calcium mobilization (V 1 ) and cyclic adenosine monophosphate (V 2 ). Binding potency at V 1 and V 2 was AVP>LVP>terlipressin. LVP and terlipressin had approximately sixfold higher affinity for V 1 than for V 2 . Cellular activity potency was also AVP>LVP>terlipressin. Terlipressin was a partial agonist at V 1 and a full agonist at V 2 ; LVP was a full agonist at both V 1 and V 2 . The in vivo response to terlipressin is likely due to the partial V 1 agonist activity of terlipressin and full V 1 agonist activity of its metabolite, LVP. These results provide supportive evidence for previous findings and further establish terlipressin pharmacology for vasopressin receptors.

  12. Melanocortin MC(4) receptor-mediated feeding and grooming in rodents.

    Science.gov (United States)

    Mul, Joram D; Spruijt, Berry M; Brakkee, Jan H; Adan, Roger A H

    2013-11-05

    Decades ago it was recognized that the pharmacological profile of melanocortin ligands that stimulated grooming behavior in rats was strikingly similar to that of Xenopus laevis melanophore pigment dispersion. After cloning of the melanocortin MC1 receptor, expressed in melanocytes, and the melanocortin MC4 receptor, expressed mainly in brain, the pharmacological profiles of these receptors appeared to be very similar and it was demonstrated that these receptors mediate melanocortin-induced pigmentation and grooming respectively. Grooming is a low priority behavior that is concerned with care of body surface. Activation of central melanocortin MC4 receptors is also associated with meal termination, and continued postprandial stimulation of melanocortin MC4 receptors may stimulate natural postprandial grooming behavior as part of the behavioral satiety sequence. Indeed, melanocortins fail to suppress food intake or induce grooming behavior in melanocortin MC4 receptor-deficient rats. This review will focus on how melanocortins affect grooming behavior through the melanocortin MC4 receptor, and how melanocortin MC4 receptors mediate feeding behavior. This review also illustrates how melanocortins were the most likely candidates to mediate grooming and feeding based on the natural behaviors they induced. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. PKCɛ mediates substance P inhibition of GABAA receptors-mediated current in rat dorsal root ganglion.

    Science.gov (United States)

    Li, Li; Zhao, Lei; Wang, Yang; Ma, Ke-tao; Shi, Wen-yan; Wang, Ying-zi; Si, Jun-qiang

    2015-02-01

    The mechanism underlying the modulatory effect of substance P (SP) on GABA-activated response in rat dorsal root ganglion (DRG) neurons was investigated. In freshly dissociated rat DRG neurons, whole-cell patch-clamp technique was used to record GABA-activated current and sharp electrode intracellular recording technique was used to record GABA-induced membrane depolarization. Application of GABA (1-1000 μmol/L) induced an inward current in a concentration-dependent manner in 114 out of 127 DRG neurons (89.8 %) examined with whole-cell patch-clamp recordings. Bath application of GABA (1-1000 μmol/L) evoked a depolarizing response in 236 out of 257 (91.8%) DRG neurons examined with intracellular recordings. Application of SP (0.001-1 μmol/L) suppressed the GABA-activated inward current and membrane depolarization. The inhibitory effects were concentration-dependent and could be blocked by the selective neurokinin 1 (NK1) receptors antagonist spantide but not by L659187 and SR142801 (1 μmol/L, n=7), selective antagonists of NK2 and NK3. The inhibitory effect of SP was significantly reduced by the calcium chelator BAPTA-AM, phospholipase C (PLC) inhibitor U73122, and PKC inhibitor chelerythrine, respectively. The PKA inhibitor H-89 did not affect the SP effect. Remarkably, the inhibitory effect of SP on GABA-activated current was nearly completely removed by a selective PKCε inhibitor epilon-V1-2 but not by safingol and LY333531, selective inhibitors of PKCα and PKCβ. Our results suggest that NK1 receptor mediates SP-induced inhibition of GABA-activated current and membrane depolarization by activating intracellular PLC-Ca²⁺-PKCε cascade. SP might regulate the excitability of peripheral nociceptors through inhibition of the "pre-synaptic inhibition" evoked by GABA, which may explain its role in pain and neurogenic inflammation.

  14. 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

    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...... in physiological relevant concentrations and responded to substances released by the artery preparation. Aldosterone treatment of mesenteric arteries from wild type mice for 50 minutes resulted in an increased number of intracellular Ca(2+) transient peaks in the biosensor cells, which was significantly inhibited...... 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...

  15. Glutamate mediates the function of melanocortin receptor 4 on sim1 neurons in body weight regulation

    Science.gov (United States)

    The melanocortin receptor 4 (MC4R) is a well-established mediator of body weight homeostasis. However, the neurotransmitter(s) that mediate MC4R function remain largely unknown; as a result, little is known about the second-order neurons of the MC4R neural pathway. Single-minded 1 (Sim1)-expressing ...

  16. Progesterone receptors (PR) mediate STAT actions: PR and prolactin receptor signaling crosstalk in breast cancer models.

    Science.gov (United States)

    Leehy, Katherine A; Truong, Thu H; Mauro, Laura J; Lange, Carol A

    2018-02-01

    Estrogen is the major mitogenic stimulus of mammary gland development during puberty wherein ER signaling acts to induce abundant PR expression. PR signaling, in contrast, is the primary driver of mammary epithelial cell proliferation in adulthood. The high circulating levels of progesterone during pregnancy signal through PR, inducing expression of the prolactin receptor (PRLR). Cooperation between PR and prolactin (PRL) signaling, via regulation of downstream components in the PRL signaling pathway including JAKs and STATs, facilitates the alveolar morphogenesis observed during pregnancy. Indeed, these pathways are fully integrated via activation of shared signaling pathways (i.e. JAKs, MAPKs) as well as by the convergence of PRs and STATs at target genes relevant to both mammary gland biology and breast cancer progression (i.e. proliferation, stem cell outgrowth, tissue cell type heterogeneity). Thus, rather than a single mediator such as ER, transcription factor cascades (ER>PR>STATs) are responsible for rapid proliferative and developmental programming in the normal mammary gland. It is not surprising that these same mediators typify uncontrolled proliferation in a majority of breast cancers, where ER and PR are most often co-expressed and may cooperate to drive malignant tumor progression. This review will primarily focus on the integration of PR and PRL signaling in breast cancer models and the importance of this cross-talk in cancer progression in the context of mammographic density. Components of these PR/PRL signaling pathways could offer alternative drug targets and logical complements to anti-ER or anti-estrogen-based endocrine therapies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Desloratadine citrate disodium injection, a potent histamine H(1) receptor antagonist, inhibits chemokine production in ovalbumin-induced allergic rhinitis guinea pig model and histamine-induced human nasal epithelial cells via inhibiting the ERK1/2 and NF-kappa B signal cascades.

    Science.gov (United States)

    Chen, Meiling; Xu, Shuhong; Zhou, Peipei; He, Guangwei; Jie, Qiong; Wu, Yulin

    2015-11-15

    Chemokines have chemotactic properties on leukocyte subsets whose modulation plays a pivotal role in allergic inflammatory processes. Our present study was designed to investigate the anti-allergic and anti-inflammatory properties of desloratadine citrate disodium injection (DLC) and elucidate the molecular mechanisms of its anti-inflammatory properties. The anti-allergic effects of DLC were evaluated based on allergic symptoms, serological marker production and histological changes of the nasal mucosa in guinea pigs model of allergic rhinitis. The anti-inflammatory properties and molecular mechanisms of DLC were explored by studying the regulation of a set of chemokines and extracellular signal-regulated kinase (ERK)1/2 and nuclear factor-kappa B (NF-κB) pathways, after DLC treatment in guinea pigs model of allergic rhinitis in vivo and histamine-activated human nasal epithelial cells (HNECs) in vitro. In vivo model in guinea pigs, DLC alleviated the rhinitis symptoms, inhibited inflammatory cells infiltration in nasal lavage fluid (NLF) and histamine, monocyte chemotactic protein (MCP)-1, regulated on activation normal T cell expressed, and presumably secreted (RANTEs) and interleukin (IL)-8 release in sera and P-ERK1/2 and NF-κB activation in nasal mucosa. In vitro, DLC markedly inhibited histamine-induced production of MCP-1, RANTEs and IL-8 and suppressed c-Raf, mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) and ERK1/2 activation in HNECs. These results provide evidence that DLC possesses potent anti-allergic and anti-inflammatory properties. The mechanism of action underlying DLC in allergic inflammation appears to be inhibition of the phosphorylation of ERK1/2, in addition to blocking of the NF-κB pathway. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. A glial variant of the vesicular monoamine transporter is required to store histamine in the Drosophila visual system.

    Directory of Open Access Journals (Sweden)

    Rafael Romero-Calderón

    2008-11-01

    Full Text Available Unlike other monoamine neurotransmitters, the mechanism by which the brain's histamine content is regulated remains unclear. In mammals, vesicular monoamine transporters (VMATs are expressed exclusively in neurons and mediate the storage of histamine and other monoamines. We have studied the visual system of Drosophila melanogaster in which histamine is the primary neurotransmitter released from photoreceptor cells. We report here that a novel mRNA splice variant of Drosophila VMAT (DVMAT-B is expressed not in neurons but rather in a small subset of glia in the lamina of the fly's optic lobe. Histamine contents are reduced by mutation of dVMAT, but can be partially restored by specifically expressing DVMAT-B in glia. Our results suggest a novel role for a monoamine transporter in glia that may be relevant to histamine homeostasis in other systems.

  19. Complement-mediated solubilization of immune complexes and their interaction with complement C3 receptors

    DEFF Research Database (Denmark)

    Petersen, Ivan; Baatrup, Gunnar; Jepsen, H H

    1985-01-01

    Some of the molecular events in the complement (C)-mediated solubilization of immune complexes (IC) have been clarified in recent years. The solubilization is primarily mediated by alternative C pathway proteins whereas factors in the classical pathway accelerate the process. Components of the me......Some of the molecular events in the complement (C)-mediated solubilization of immune complexes (IC) have been clarified in recent years. The solubilization is primarily mediated by alternative C pathway proteins whereas factors in the classical pathway accelerate the process. Components...... of the cellular localization, expression and structure of the C3 receptors, especially the C3b (CR1) receptor, has been considerably extended in the last few years, whereas our understanding of the physiological role of these receptors is still fragmentary. However, it is becoming increasingly evident...

  20. Nicotine impairs cyclooxygenase-2-dependent kinin-receptor-mediated murine airway relaxations

    International Nuclear Information System (INIS)

    Xu, Yuan; Cardell, Lars-Olaf

    2014-01-01

    Introduction: Cigarette smoke induces local inflammation and airway hyperreactivity. In asthmatics, it worsens the symptoms and increases the risk for exacerbation. The present study investigates the effects of nicotine on airway relaxations in isolated murine tracheal segments. Methods: Segments were cultured for 24 h in the presence of vehicle, nicotine (10 μM) and/or dexamethasone (1 μM). Airway relaxations were assessed in myographs after pre-contraction with carbachol (1 μM). Kinin receptors, cyclooxygenase (COX) and inflammatory mediator expressions were assessed by real-time PCR and confocal-microscopy-based immunohistochemistry. Results: The organ culture procedure markedly increased bradykinin- (selective B 2 receptor agonist) and des-Arg 9 -bradykinin- (selective B 1 receptor agonist) induced relaxations, and slightly increased relaxation induced by isoprenaline, but not that induced by PGE 2 . The kinin receptor mediated relaxations were epithelium-, COX-2- and EP2-receptor-dependent and accompanied by drastically enhanced mRNA levels of kinin receptors, as well as inflammatory mediators MCP-1 and iNOS. Increase in COX-2 and mPGES-1 was verified both at mRNA and protein levels. Nicotine selectively suppressed the organ-culture-enhanced relaxations induced by des-Arg 9 -bradykinin and bradykinin, at the same time reducing mPGES-1 mRNA and protein expressions. α7-nicotinic acetylcholine receptor inhibitors α-bungarotoxin and MG624 both blocked the nicotine effects on kinin B 2 receptors, but not those on B 1 . Dexamethasone completely abolished kinin-induced relaxations. Conclusion: It is tempting to conclude that a local inflammatory process per se could have a bronchoprotective component by increasing COX-2 mediated airway relaxations and that nicotine could impede this safety mechanism. Dexamethasone further reduced airway inflammation together with relaxations. This might contribute to the steroid resistance seen in some patients with asthma

  1. Nicotine impairs cyclooxygenase-2-dependent kinin-receptor-mediated murine airway relaxations

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuan, E-mail: yuan.xu@ki.se; Cardell, Lars-Olaf

    2014-02-15

    Introduction: Cigarette smoke induces local inflammation and airway hyperreactivity. In asthmatics, it worsens the symptoms and increases the risk for exacerbation. The present study investigates the effects of nicotine on airway relaxations in isolated murine tracheal segments. Methods: Segments were cultured for 24 h in the presence of vehicle, nicotine (10 μM) and/or dexamethasone (1 μM). Airway relaxations were assessed in myographs after pre-contraction with carbachol (1 μM). Kinin receptors, cyclooxygenase (COX) and inflammatory mediator expressions were assessed by real-time PCR and confocal-microscopy-based immunohistochemistry. Results: The organ culture procedure markedly increased bradykinin- (selective B{sub 2} receptor agonist) and des-Arg{sup 9}-bradykinin- (selective B{sub 1} receptor agonist) induced relaxations, and slightly increased relaxation induced by isoprenaline, but not that induced by PGE{sub 2}. The kinin receptor mediated relaxations were epithelium-, COX-2- and EP2-receptor-dependent and accompanied by drastically enhanced mRNA levels of kinin receptors, as well as inflammatory mediators MCP-1 and iNOS. Increase in COX-2 and mPGES-1 was verified both at mRNA and protein levels. Nicotine selectively suppressed the organ-culture-enhanced relaxations induced by des-Arg{sup 9}-bradykinin and bradykinin, at the same time reducing mPGES-1 mRNA and protein expressions. α7-nicotinic acetylcholine receptor inhibitors α-bungarotoxin and MG624 both blocked the nicotine effects on kinin B{sub 2} receptors, but not those on B{sub 1}. Dexamethasone completely abolished kinin-induced relaxations. Conclusion: It is tempting to conclude that a local inflammatory process per se could have a bronchoprotective component by increasing COX-2 mediated airway relaxations and that nicotine could impede this safety mechanism. Dexamethasone further reduced airway inflammation together with relaxations. This might contribute to the steroid resistance seen in

  2. The Role of Cgrp-Receptor Component Protein (Rcp in Cgrp-Mediated Signal Transduction

    Directory of Open Access Journals (Sweden)

    M. A. Prado

    2001-01-01

    Full Text Available The calcitonin gene-related peptide (CGRP-receptor component protein (RCP is a 17-kDa intracellular peripheral membrane protein required for signal transduction at CGRP receptors. To determine the role of RCP in CGRP-mediated signal transduction, RCP was depleted from NIH3T3 cells using antisense strategy. Loss of RCP protein correlated with loss of cAMP production by CGRP in the antisense cells. In contrast, loss of RCP had no effect on CGRP-mediated binding; therefore RCP is not acting as a chaperone for the CGRP receptor. Instead, RCP is a novel signal transduction molecule that couples the CGRP receptor to the cellular signal transduction machinery. RCP thus represents a prototype for a new class of signal transduction proteins that are required for regulation of G protein-coupled receptors.

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

    Science.gov (United States)

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

    2013-12-23

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

  4. GABA-A Receptors Mediate Tonic Inhibition and Neurosteroid Sensitivity in the Brain.

    Science.gov (United States)

    Reddy, Doodipala Samba

    2018-01-01

    Neurosteroids like allopregnanolone (AP) are positive allosteric modulators of synaptic and extrasynaptic GABA-A receptors. AP and related neurosteroids exhibit a greater potency for δ-containing extrasynaptic receptors. The δGABA-A receptors, which are expressed extrasynaptically in the dentate gyrus and other regions, contribute to tonic inhibition, promoting network shunting as well as reducing seizure susceptibility. Levels of endogenous neurosteroids fluctuate with ovarian cycle. Natural and synthetic neurosteroids maximally potentiate tonic inhibition in the hippocampus and provide robust protection against a variety of limbic seizures and status epilepticus. Recently, a consensus neurosteroid pharmacophore model has been proposed at extrasynaptic δGABA-A receptors based on structure-activity relationship for functional activation of tonic currents and seizure protection. Aside from anticonvulsant actions, neurosteroids have been found to be powerful anxiolytic and anesthetic agents. Neurosteroids and Zn 2+ have preferential affinity for δ-containing receptors. Thus, Zn 2+ can prevent neurosteroid activation of extrasynaptic δGABA-A receptor-mediated tonic inhibition. Recently, we demonstrated that Zn 2+ selectively inhibits extrasynaptic δGABA-A receptors and thereby fully prevents AP activation of tonic inhibition and seizure protection. We confirmed that neurosteroids exhibit greater sensitivity at extrasynaptic δGABA-A receptors. Overall, extrasynaptic GABA-A receptors are primary mediators of tonic inhibition in the brain and play a key role in the pathophysiology of epilepsy and other neurological disorders. © 2018 Elsevier Inc. All rights reserved.

  5. 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.

  6. G-protein mediates voltage regulation of agonist binding to muscarinic receptors: effects on receptor-Na+ channel interaction

    International Nuclear Information System (INIS)

    Cohen-Armon, M.; Garty, H.; Sokolovsky, M.

    1988-01-01

    The authors previous experiments in membranes prepared from rat heart and brain led them to suggest that the binding of agonist to the muscarinic receptors and to the Na + channels is a coupled event mediated by guanine nucleotide binding protein(s) [G-protein(s)]. These in vitro findings prompted us to employ synaptoneurosomes from brain stem tissue to examine (i) the binding properties of [ 3 H] acetylcholine at resting potential and under depolarization conditions in the absence and presence of pertussis toxin; (ii) the binding of [ 3 H]batrachotoxin to Na + channel(s) in the presence of the muscarinic agonists; and (iii) muscarinically induced 22 Na + uptake in the presence and absence of tetrodotoxin, which blocks Na + channels. The findings indicate that agonist binding to muscarinic receptors is voltage dependent, that this process is mediated by G-protein(s), and that muscarinic agonists induce opening of Na + channels. The latter process persists even after pertussis toxin treatment, indicating that it is not likely to be mediated by pertussis toxin sensitive G-protein(s). The system with its three interacting components-receptor, G-protein, and Na + channel-is such that at resting potential the muscarinic receptor induces opening of Na + channels; this property may provide a possible physiological mechanism for the depolarization stimulus necessary for autoexcitation or repetitive firing in heart or brain tissues

  7. β-Adrenergic receptor-mediated suppression of interleukin 2 receptors in human lymphocytes

    International Nuclear Information System (INIS)

    Feldman, R.D.; Hunninghake, G.W.; McArdle, W.L.

    1987-01-01

    Adrenergic receptor agonists are know to attenuate the proliferative response of human lymphocytes after activation; however, their mechanism of action is unknown. Since expression of interleukin 2 (IL-2) receptors is a prerequisite for proliferation, the effect of β-adrenergic receptor agonists on lymphocyte IL-2 receptors was studied on both mitogen-stimulated lymphocytes and IL-2-dependent T lymphocyte cell lines. In both cell types the β-adrenergic receptor agonist isoproterenol blocked the expression of IL-2 receptors, as determined with the IL-2 receptor anti-TAC antibody. To determine the effect of β-adrenergic agonists on expression of the high affinity IL-2 receptors, [ 125 I]IL-2 binding studies were performed at concentrations selective for high affinity sites. No significant effect of β-adrenergic agonists on high affinity IL-2 receptor sites could be detected. The data demonstrate that β-adrenergic receptor agonists down-regulate IL-2 receptors primarily affecting low affinity sites

  8. Suppression of Thyroid Hormone Receptor-Mediated Transcription ...

    African Journals Online (AJOL)

    TH)-induced TR-mediated transcription. We further examined the effects of methamidophos on TR-thyroid hormone response element (TRE) binding using the liquid chemiluminescent DNA pull-down assay (LCDPA), and found no dissociation of ...

  9. Investigating the Regulation of Estrogen Receptor-Mediated Transcription

    National Research Council Canada - National Science Library

    Thackray, Varykina

    2002-01-01

    ...-mediated regulation of specific target genes are still lacking. We have developed an estrogen responsive system in the fruit fly, Drosophila melanogaster in order to explore the functional interactions between ER and other cellular proteins...

  10. Investigating the Regulation of Estrogen Receptor-Mediated Transcription

    National Research Council Canada - National Science Library

    Thackray, Varykina

    2001-01-01

    ...-mediated regulation of specific target genes are still lacking. We have developed an estrogen responsive system in the fruit fly, Drosophila melanogaster in order to explore the functional interactions between ER and other cellular proteins...

  11. 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...... and subsequently determined the frequency of HR-Urticaria-positive sera from a larger population of CU patients....

  12. Skin reactions to histamine of healthy subjects after hypnotically induced emotions of sadness, anger, and happiness.

    Science.gov (United States)

    Zachariae, R; Jørgensen, M M; Egekvist, H; Bjerring, P

    2001-08-01

    The severity of symptoms in asthma and other hypersensitivity-related disorders has been associated with changes in mood but little is known about the mechanisms possibly mediating such a relationship. The purpose of this study was to examine the influence of mood on skin reactivity to histamine by comparing the effects of hypnotically induced emotions on flare and wheal reactions to cutaneous histamine prick tests. Fifteen highly hypnotically susceptible volunteers had their cutaneous reactivity to histamine measured before hypnosis at 1, 2, 3, 4, 5, 10, and 15 min after the histamine prick. These measurements were repeated under three hypnotically induced emotions of sadness, anger, and happiness presented in a counterbalanced order. Skin reactions were measured as change in histamine flare and wheal area in mm2 per minute. The increase in flare reaction in the time interval from 1 to 3 min during happiness and anger was significantly smaller than flare reactions during sadness (P<0.05). No effect of emotion was found for wheal reactions. Hypnotic susceptibility scores were associated with increased flare reactions at baseline (r=0.56; P<0.05) and during the condition of happiness (r=0.56; P<0.05). Our results agree with previous studies showing mood to be a predictor of cutaneous immediate-type hypersensitivity and histamine skin reactions. The results are also in concordance with earlier findings of an association between hypnotic susceptibility and increased reactivity to an allergen.

  13. 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.

  14. Mast cell mediators in citric acid-induced airway constriction of guinea pigs

    International Nuclear Information System (INIS)

    Lin, C.-H.; Lai, Y.-L.

    2005-01-01

    We demonstrated previously that mast cells play an important role in citric acid (CA)-induced airway constriction. In this study, we further investigated the underlying mediator(s) for this type of airway constriction. At first, to examine effects caused by blocking agents, 67 young Hartley guinea pigs were divided into 7 groups: saline + CA; methysergide (serotonin receptor antagonist) + CA; MK-886 (leukotriene synthesis inhibitor) + CA; mepyramine (histamine H 1 receptor antagonist) + CA; indomethacin (cyclooxygenase inhibitor) + CA; cromolyn sodium (mast cell stabilizer) + CA; and compound 48/80 (mast cell degranulating agent) + CA. Then, we tested whether leukotriene C 4 (LTC 4 ) or histamine enhances CA-induced airway constriction in compound 48/80-pretreated guinea pigs. We measured dynamic respiratory compliance (Crs) and forced expiratory volume in 0.1 s (FEV 0.1 ) during either baseline or recovery period. In addition, we detected histamine level, an index of pulmonary mast cell degranulation, in bronchoalveolar lavage (BAL) samples. Citric acid aerosol inhalation caused decreases in Crs and FEV 0.1 , indicating airway constriction in the control group. This airway constriction was significantly attenuated by MK-886, mepyramine, cromolyn sodium, and compound 48/80, but not by either methysergide or indomethacin. Both LTC 4 and histamine infusion significantly increased the magnitude of CA-induced airway constriction in compound 48/80-pretreated guinea pigs. Citric acid inhalation caused significant increase in histamine level in the BAL sample, which was significantly suppressed by compound 48/80. These results suggest that leukotrienes and histamine originating from mast cells play an important role in CA inhalation-induced noncholinergic airway constriction

  15. Receptor tyrosine phosphatase R-PTP-kappa mediates homophilic binding

    DEFF Research Database (Denmark)

    Sap, J; Jiang, Y P; Friedlander, D

    1994-01-01

    Receptor tyrosine phosphatases (R-PTPases) feature PTPase domains in the context of a receptor-like transmembrane topology. The R-PTPase R-PTP-kappa displays an extracellular domain composed of fibronectin type III motifs, a single immunoglobulin domain, as well as a recently defined MAM domain (Y...... not require PTPase activity or posttranslational proteolytic cleavage of the R-PTP-kappa protein and is calcium independent. The results suggest that R-PTPases may provide a link between cell-cell contact and cellular signaling events involving tyrosine phosphorylation....

  16. Testin, a novel binding partner of the calcium-sensing receptor, enhances receptor-mediated Rho-kinase signalling

    International Nuclear Information System (INIS)

    Magno, Aaron L.; Ingley, Evan; Brown, Suzanne J.; Conigrave, Arthur D.; Ratajczak, Thomas; Ward, Bryan K.

    2011-01-01

    Highlights: → A yeast two-hybrid screen revealed testin bound to the calcium-sensing receptor. → The second zinc finger of LIM domain 1 of testin is critical for interaction. → Testin bound to a region of the receptor tail important for cell signalling. → Testin and receptor interaction was confirmed in mammalian (HEK293) cells. → Overexpression of testin enhanced receptor-mediated Rho signalling in HEK293 cells. -- Abstract: The calcium-sensing receptor (CaR) plays an integral role in calcium homeostasis and the regulation of other cellular functions including cell proliferation and cytoskeletal organisation. The multifunctional nature of the CaR is manifested through ligand-dependent stimulation of different signalling pathways that are also regulated by partner binding proteins. Following a yeast two-hybrid library screen using the intracellular tail of the CaR as bait, we identified several novel binding partners including the focal adhesion protein, testin. Testin has not previously been shown to interact with cell surface receptors. The sites of interaction between the CaR and testin were mapped to the membrane proximal region of the receptor tail and the second zinc-finger of LIM domain 1 of testin, the integrity of which was found to be critical for the CaR-testin interaction. The CaR-testin association was confirmed in HEK293 cells by coimmunoprecipitation and confocal microscopy studies. Ectopic expression of testin in HEK293 cells stably expressing the CaR enhanced CaR-stimulated Rho activity but had no effect on CaR-stimulated ERK signalling. These results suggest an interplay between the CaR and testin in the regulation of CaR-mediated Rho signalling with possible effects on the cytoskeleton.

  17. Regulated internalization of NMDA receptors drives PKD1-mediated suppression of the activity of residual cell-surface NMDA receptors.

    Science.gov (United States)

    Fang, Xiao-Qian; Qiao, Haifa; Groveman, Bradley R; Feng, Shuang; Pflueger, Melissa; Xin, Wen-Kuan; Ali, Mohammad K; Lin, Shuang-Xiu; Xu, Jindong; Duclot, Florian; Kabbaj, Mohamed; Wang, Wei; Ding, Xin-Sheng; Santiago-Sim, Teresa; Jiang, Xing-Hong; Salter, Michael W; Yu, Xian-Min

    2015-11-19

    Constitutive and regulated internalization of cell surface proteins has been extensively investigated. The regulated internalization has been characterized as a principal mechanism for removing cell-surface receptors from the plasma membrane, and signaling to downstream targets of receptors. However, so far it is still not known whether the functional properties of remaining (non-internalized) receptor/channels may be regulated by internalization of the same class of receptor/channels. The N-methyl-D-aspartate receptor (NMDAR) is a principal subtype of glutamate-gated ion channel and plays key roles in neuronal plasticity and memory functions. NMDARs are well-known to undergo two types of regulated internalization - homologous and heterologous, which can be induced by high NMDA/glycine and DHPG, respectively. In the present work, we investigated effects of regulated NMDAR internalization on the activity of residual cell-surface NMDARs and neuronal functions. In electrophysiological experiments we discovered that the regulated internalization of NMDARs not only reduced the number of cell surface NMDARs but also caused an inhibition of the activity of remaining (non-internalized) surface NMDARs. In biochemical experiments we identified that this functional inhibition of remaining surface NMDARs was mediated by increased serine phosphorylation of surface NMDARs, resulting from the activation of protein kinase D1 (PKD1). Knockdown of PKD1 did not affect NMDAR internalization but prevented the phosphorylation and inhibition of remaining surface NMDARs and NMDAR-mediated synaptic functions. These data demonstrate a novel concept that regulated internalization of cell surface NMDARs not only reduces the number of NMDARs on the cell surface but also causes an inhibition of the activity of remaining surface NMDARs through intracellular signaling pathway(s). Furthermore, modulating the activity of remaining surface receptors may be an effective approach for treating receptor

  18. Absence of histamine-induced itch in the African naked mole-rat and "rescue" by Substance P.

    Science.gov (United States)

    Smith, Ewan St John; Blass, Gregory R C; Lewin, Gary R; Park, Thomas J

    2010-05-24

    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.

  19. 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.

  20. Nuclear Receptor Cofactors in PPARγ-Mediated Adipogenesis and Adipocyte Energy Metabolism

    Directory of Open Access Journals (Sweden)

    Emily Powell

    2007-01-01

    Full Text Available Transcriptional cofactors are integral to the proper function and regulation of nuclear receptors. Members of the peroxisome proliferator-activated receptor (PPAR family of nuclear receptors are involved in the regulation of lipid and carbohydrate metabolism. They modulate gene transcription in response to a wide variety of ligands, a process that is mediated by transcriptional coactivators and corepressors. The mechanisms by which these cofactors mediate transcriptional regulation of nuclear receptor function are still being elucidated. The rapidly increasing array of cofactors has brought into focus the need for a clear understanding of how these cofactors interact in ligand- and cell-specific manners. This review highlights the differential effects of the assorted cofactors regulating the transcriptional action of PPARγ and summarizes the recent advances in understanding the physiological functions of corepressors and coactivators.

  1. Upregulation of endothelin ETB receptor-mediated vasoconstriction in rat coronary artery after organ culture

    DEFF Research Database (Denmark)

    Eskesen, Karen; Edvinsson, Lars

    2006-01-01

    The aim of this study was to examine if endothelin ET(B) receptor-mediated contraction occurred in isolated segments of rat coronary arteries during organ culture. Presence of contractile endothelin ET(B) receptors was studied by measuring the change in isometric tension in rings of left anterior......(+)-solution was not modified after 1 day in culture medium. The experiments indicate that organ culture of rat coronary arteries upregulate endothelin ET(B) receptor-mediated contraction by inducing synthesis of new protein....... descending coronary arteries isolated from hearts of rats as response to application of the selective endothelin ET(B) receptor agonist, Sarafotoxin 6c and endothelin-1. In segments cultured 1 day in serum free Dulbecco's Modified Eagle's Medium, Sarafotoxin 6c induced a concentration dependent contraction...

  2. Different perception levels of histamine-induced itch sensation in young adult mice.

    Science.gov (United States)

    Ji, Yeounjung; Jang, Yongwoo; Lee, Wook Joo; Yang, Young Duk; Shim, Won-Sik

    2018-05-01

    Itch is an unpleasant sensation that evokes behavioral responses such as scratching the skin. Interestingly, it is conceived that the perception of itch sensation is influenced by age. Indeed, accumulating evidence supports the idea that even children or younger adults show distinctive itch sensation depending on age. This evidence implies the presence of a mechanism that regulates the perception of itch sensation in an age-dependent fashion. Therefore, the purpose of the present study was to investigate a putative mechanism for the age-dependent perception of itch sensation by comparing histamine-induced scratching behaviors in 45-day old (D45) and 75-day old male "young adult" mice. The results indicated that, following histamine administration, the D75 mice spent a longer time scratching than D45 mice. However, the intensity of the calcium influx induced by histamine in primary culture of dorsal root ganglia (DRG) neurons was not different between D45 and D75 mice. Moreover, no apparent difference was observed in mRNA levels of a characteristic His-related receptor and ion channel. In contrast, the mRNA levels of Toll-Like Receptor 4 (TLR4) were increased approximately by two-fold in D75 DRG compared with D45 DRG. Additionally, D75-derived DRG neurons exhibited enhanced intracellular calcium increase by lipopolysaccharide (LPS, a TLR4 agonist) than those of D45 mice. Furthermore, intensities of calcium influx induced by histamine were significantly potentiated when co-treated with LPS in D75 DRG neurons, but not in those of D45 mice. Thus, it appears that D75 mice showed enhanced histamine-induced scratching behaviors not by increased expression levels of histamine-related genes, but probably due to augmented TLR4 expression in DRG neurons. Consequently, the current study found that different perception levels of histamine-induced itch sensation are present in different age groups of young adult mice. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Dynamics of the actin cytoskeleton mediates receptor cross talk: An emerging concept in tuning receptor signaling

    Science.gov (United States)

    Mattila, Pieta K.; Batista, Facundo D.

    2016-01-01

    Recent evidence implicates the actin cytoskeleton in the control of receptor signaling. This may be of particular importance in the context of immune receptors, such as the B cell receptor, where dysregulated signaling can result in autoimmunity and malignancy. Here, we discuss the role of the actin cytoskeleton in controlling receptor compartmentalization, dynamics, and clustering as a means to regulate receptor signaling through controlling the interactions with protein partners. We propose that the actin cytoskeleton is a point of integration for receptor cross talk through modulation of protein dynamics and clustering. We discuss the implication of this cross talk via the cytoskeleton for both ligand-induced and low-level constitutive (tonic) signaling necessary for immune cell survival. PMID:26833785

  4. Fas receptor-mediated apoptosis : a clinical application?

    NARCIS (Netherlands)

    Timmer, T; de Vries, EGE; de Jong, S

    Fas is a membrane protein belonging to the death receptor family. Cross-linking of Fas by its ligand, FasL, or agonistic anti-Fas antibodies, induces apoptosis of cells expressing Fas on the membrane by triggering a cascade of caspases. Since many different tumours express Fas on their membrane,

  5. 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

  6. Stimulation of accumbal GABAA receptors inhibits delta2-, but not delta1-, opioid receptor-mediated dopamine efflux in the nucleus accumbens of freely moving rats.

    Science.gov (United States)

    Aono, Yuri; Kiguchi, Yuri; Watanabe, Yuriko; Waddington, John L; Saigusa, Tadashi

    2017-11-15

    The nucleus accumbens contains delta-opioid receptors that may reduce inhibitory neurotransmission. Reduction in GABA A receptor-mediated inhibition of accumbal dopamine release due to delta-opioid receptor activation should be suppressed by stimulating accumbal GABA A receptors. As delta-opioid receptors are divided into delta2- and delta1-opioid receptors, we analysed the effects of the GABA A receptor agonist muscimol on delta2- and delta1-opioid receptor-mediated accumbal dopamine efflux in freely moving rats using in vivo microdialysis. Drugs were administered intracerebrally through the dialysis probe. Doses of compounds indicate total amount administered (mol) during 25-50min infusions. The delta2-opioid receptor agonist deltorphin II (25.0nmol)- and delta1-opioid receptor agonist DPDPE (5.0nmol)-induced increases in dopamine efflux were inhibited by the delta2-opioid receptor antagonist naltriben (1.5nmol) and the delta1-opioid receptor antagonist BNTX (150.0pmol), respectively. Muscimol (250.0pmol) inhibited deltorphin II (25.0nmol)-induced dopamine efflux. The GABA A receptor antagonist bicuculline (50.0pmol), which failed to affect deltorphin II (25.0nmol)-induced dopamine efflux, counteracted the inhibitory effect of muscimol on deltorphin II-induced dopamine efflux. Neither muscimol (250.0pmol) nor bicuculline (50.0 and 500.0pmol) altered DPDPE (5.0nmol)-induced dopamine efflux. The present results show that reduction in accumbal GABA A receptor-mediated inhibition of dopaminergic activity is necessary to produce delta2-opioid receptor-induced increase in accumbal dopamine efflux. This study indicates that activation of delta2- but not delta1-opioid receptors on the cell bodies and/or terminals of accumbal GABAergic interneurons inhibits GABA release and, accordingly, decreases GABA A receptor-mediated inhibition of dopaminergic terminals, resulting in enhanced accumbal dopamine efflux. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Comparison of lentiviral and sleeping beauty mediated αβ T cell receptor gene transfer.

    Directory of Open Access Journals (Sweden)

    Anne-Christine Field

    Full Text Available Transfer of tumour antigen-specific receptors to T cells requires efficient delivery and integration of transgenes, and currently most clinical studies are using gamma retroviral or lentiviral systems. Whilst important proof-of-principle data has been generated for both chimeric antigen receptors and αβ T cell receptors, the current platforms are costly, time-consuming and relatively inflexible. Alternative, more cost-effective, Sleeping Beauty transposon-based plasmid systems could offer a pathway to accelerated clinical testing of a more diverse repertoire of recombinant high affinity T cell receptors. Nucleofection of hyperactive SB100X transposase-mediated stable transposition of an optimised murine-human chimeric T cell receptor specific for Wilm's tumour antigen from a Sleeping Beauty transposon plasmid. Whilst transfer efficiency was lower than that mediated by lentiviral transduction, cells could be readily enriched and expanded, and mediated effective target cells lysis in vitro and in vivo. Integration sites of transposed TCR genes in primary T cells were almost randomly distributed, contrasting the predilection of lentiviral vectors for transcriptionally active sites. The results support exploitation of the Sleeping Beauty plasmid based system as a flexible and adaptable platform for accelerated, early-phase assessment of T cell receptor gene therapies.

  8. The orphan receptor ALK7 and the Activin receptor ALK4 mediate signaling by Nodal proteins during vertebrate development

    Science.gov (United States)

    Reissmann, Eva; Jörnvall, Henrik; Blokzijl, Andries; Andersson, Olov; Chang, Chenbei; Minchiotti, Gabriella; Persico, M. Graziella; Ibáñez, Carlos F.; Brivanlou, Ali H.

    2001-01-01

    Nodal proteins have crucial roles in mesendoderm formation and left–right patterning during vertebrate development. The molecular mechanisms of signal transduction by Nodal and related ligands, however, are not fully understood. In this paper, we present biochemical and functional evidence that the orphan type I serine/threonine kinase receptor ALK7 acts as a receptor for mouse Nodal and Xenopus Nodal-related 1 (Xnr1). Receptor reconstitution experiments indicate that ALK7 collaborates with ActRIIB to confer responsiveness to Xnr1 and Nodal. Both receptors can independently bind Xnr1. In addition, Cripto, an extracellular protein genetically implicated in Nodal signaling, can independently interact with both Xnr1 and ALK7, and its expression greatly enhances the ability of ALK7 and ActRIIB to respond to Nodal ligands. The Activin receptor ALK4 is also able to mediate Nodal signaling but only in the presence of Cripto, with which it can also interact directly. A constitutively activated form of ALK7 mimics the mesendoderm-inducing activity of Xnr1 in Xenopus embryos, whereas a dominant-negative ALK7 specifically blocks the activities of Nodal and Xnr1 but has little effect on other related ligands. In contrast, a dominant-negative ALK4 blocks all mesoderm-inducing ligands tested, including Nodal, Xnr1, Xnr2, Xnr4, and Activin. In agreement with a role in Nodal signaling, ALK7 mRNA is localized to the ectodermal and organizer regions of Xenopus gastrula embryos and is expressed during early stages of mouse embryonic development. Therefore, our results indicate that both ALK4 and ALK7 can mediate signal transduction by Nodal proteins, although ALK7 appears to be a receptor more specifically dedicated to Nodal signaling. PMID:11485994

  9. Dynamics of Receptor-Mediated Nanoparticle Internalization into Endothelial Cells

    Science.gov (United States)

    Gonzalez-Rodriguez, David; Barakat, Abdul I.

    2015-01-01

    Nanoparticles offer a promising medical tool for targeted drug delivery, for example to treat inflamed endothelial cells during the development of atherosclerosis. To inform the design of such therapeutic strategies, we develop a computational model of nanoparticle internalization into endothelial cells, where internalization is driven by receptor-ligand binding and limited by the deformation of the cell membrane and cytoplasm. We specifically consider the case of nanoparticles targeted against ICAM-1 receptors, of relevance for treating atherosclerosis. The model computes the kinetics of the internalization process, the dynamics of binding, and the distribution of stresses exerted between the nanoparticle and the cell membrane. The model predicts the existence of an optimal nanoparticle size for fastest internalization, consistent with experimental observations, as well as the role of bond characteristics, local cell mechanical properties, and external forces in the nanoparticle internalization process. PMID:25901833

  10. Receptor targeting of hemoglobin mediated by the haptoglobins

    DEFF Research Database (Denmark)

    Nielsen, Marianne Jensby; Moestrup, Søren Kragh

    2009-01-01

    Haptoglobin, the haptoglobin-hemoglobin receptor CD163, and the heme oxygenase-1 are proteins with a well-established function in the clearance and metabolism of "free" hemoglobin released during intravascular hemolysis. This scavenging system counteracts the potentially harmful oxidative and NO......-scavenging effects associated with "free" hemoglobin, and, furthermore, elicits an anti-inflammatory response. In the late primate evolution, haptoglobin variants with distinct functions have arisen, including haptoglobin polymers and the haptoglobin-related protein. The latter associates with a subspecies of high......-density lipoprotein (HDL) particles playing a crucial role in the innate immunity against certain trypanosome parasites. Recent studies have elucidated this fairly sophisticated immune defense mechanism that takes advantage of a trypanosomal haptoglobin-hemoglobin receptor evolved to supply the parasite with heme...

  11. Outline of therapeutic interventions with muscarinic receptor-mediated transmission

    Czech Academy of Sciences Publication Activity Database

    Jakubík, Jan; Šantrůčková, Eva; Randáková, Alena; Janíčková, Helena; Zimčík, Pavel; Rudajev, Vladimír; Michal, Pavel; El-Fakahany, E. E.; Doležal, Vladimír

    2014-01-01

    Roč. 63, Suppl.1 (2014), S177-S189 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA305/09/0681; GA ČR(CZ) GAP304/12/0259; GA MŠk(CZ) 7E10060 Institutional support: RVO:67985823 Keywords : cholinergic transmission * muscarinic receptors * therapy * Alzheimer's disease, * schizophrenia Subject RIV: ED - Physiology Impact factor: 1.293, year: 2014

  12. Distinct phosphotyrosines on a growth factor receptor bind to specific molecules that mediate different signaling pathways.

    Science.gov (United States)

    Fantl, W J; Escobedo, J A; Martin, G A; Turck, C W; del Rosario, M; McCormick, F; Williams, L T

    1992-05-01

    The receptor for platelet-derived growth factor (PDGF) binds two proteins containing SH2 domains, GTPase activating protein (GAP) and phosphatidylinositol 3-kinase (PI3-kinase). The sites on the receptor that mediate this interaction were identified by using phosphotyrosine-containing peptides representing receptor sequences to block specifically binding of either PI3-kinase or GAP. These results suggested that PI3-kinase binds two phosphotyrosine residues, each located in a 5 aa motif with an essential methionine at the fourth position C-terminal to the tyrosine. Point mutations at these sites caused a selective elimination of PI3-kinase binding and loss of PDGF-stimulated DNA synthesis. Mutation of the binding site for GAP prevented the receptor from associating with or phosphorylating GAP, but had no effect on PI3-kinase binding and little effect on DNA synthesis. Therefore, GAP and PI3-kinase interact with the receptor by binding to different phosphotyrosine-containing sequence motifs.

  13. Azadirachtin interacts with retinoic acid receptors and inhibits retinoic acid-mediated biological responses.

    Science.gov (United States)

    Thoh, Maikho; Babajan, Banaganapalli; Raghavendra, Pongali B; Sureshkumar, Chitta; Manna, Sunil K

    2011-02-11

    Considering the role of retinoids in regulation of more than 500 genes involved in cell cycle and growth arrest, a detailed understanding of the mechanism and its regulation is useful for therapy. The extract of the medicinal plant Neem (Azadirachta indica) is used against several ailments especially for anti-inflammatory, anti-itching, spermicidal, anticancer, and insecticidal activities. In this report we prove the detailed mechanism on the regulation of retinoic acid-mediated cell signaling by azadirachtin, active components of neem extract. Azadirachtin repressed all trans-retinoic acid (ATRA)-mediated nuclear transcription factor κB (NF-κB) activation, not the DNA binding but the NF-κB-dependent gene expression. It did not inhibit IκBα degradation, IκBα kinase activity, or p65 phosphorylation and its nuclear translocation but inhibited NF-κB-dependent reporter gene expression. Azadirachtin inhibited TRAF6-mediated, but not TRAF2-mediated NF-κB activation. It inhibited ATRA-induced Sp1 and CREB (cAMP-response element-binding protein) DNA binding. Azadirachtin inhibited ATRA binding with retinoid receptors, which is supported by biochemical and in silico evidences. Azadirachtin showed strong interaction with retinoid receptors. It suppressed ATRA-mediated removal of retinoid receptors, bound with DNA by inhibiting ATRA binding to its receptors. Overall, our data suggest that azadirachtin interacts with retinoic acid receptors and suppresses ATRA binding, inhibits falling off the receptors, and activates transcription factors like CREB, Sp1, NF-κB, etc. Thus, azadirachtin exerts anti-inflammatory and anti-metastatic responses by a novel pathway that would be beneficial for further anti-inflammatory and anti-cancer therapies.

  14. Azadirachtin Interacts with Retinoic Acid Receptors and Inhibits Retinoic Acid-mediated Biological Responses*

    Science.gov (United States)

    Thoh, Maikho; Babajan, Banaganapalli; Raghavendra, Pongali B.; Sureshkumar, Chitta; Manna, Sunil K.

    2011-01-01

    Considering the role of retinoids in regulation of more than 500 genes involved in cell cycle and growth arrest, a detailed understanding of the mechanism and its regulation is useful for therapy. The extract of the medicinal plant Neem (Azadirachta indica) is used against several ailments especially for anti-inflammatory, anti-itching, spermicidal, anticancer, and insecticidal activities. In this report we prove the detailed mechanism on the regulation of retinoic acid-mediated cell signaling by azadirachtin, active components of neem extract. Azadirachtin repressed all trans-retinoic acid (ATRA)-mediated nuclear transcription factor κB (NF-κB) activation, not the DNA binding but the NF-κB-dependent gene expression. It did not inhibit IκBα degradation, IκBα kinase activity, or p65 phosphorylation and its nuclear translocation but inhibited NF-κB-dependent reporter gene expression. Azadirachtin inhibited TRAF6-mediated, but not TRAF2-mediated NF-κB activation. It inhibited ATRA-induced Sp1 and CREB (cAMP-response element-binding protein) DNA binding. Azadirachtin inhibited ATRA binding with retinoid receptors, which is supported by biochemical and in silico evidences. Azadirachtin showed strong interaction with retinoid receptors. It suppressed ATRA-mediated removal of retinoid receptors, bound with DNA by inhibiting ATRA binding to its receptors. Overall, our data suggest that azadirachtin interacts with retinoic acid receptors and suppresses ATRA binding, inhibits falling off the receptors, and activates transcription factors like CREB, Sp1, NF-κB, etc. Thus, azadirachtin exerts anti-inflammatory and anti-metastatic responses by a novel pathway that would be beneficial for further anti-inflammatory and anti-cancer therapies. PMID:21127062

  15. Increased release of histamine in patients with respiratory symptoms related to perfume.

    Science.gov (United States)

    Elberling, J; Skov, P S; Mosbech, H; Holst, H; Dirksen, A; Johansen, J D

    2007-11-01

    Environmental perfume exposure may cause respiratory symptoms. Individuals with asthma and perfume contact allergy report such symptoms more frequently than others. However, immunologic mechanisms have not been demonstrated and the symptoms are not associated with IgE-mediated allergy. The study aimed to investigate whether basophils from patients with respiratory symptoms related to perfume released more histamine in the presence of perfume as compared with healthy volunteers. Histamine release was measured by the glass fibre method. Blood was obtained from healthy volunteers (n=20) and patients with respiratory symptoms related to perfume (n=17) attending a dermatological outpatient clinic for patch testing. The effect of an international brand perfume was investigated using the basophil histamine release test with perfume. Furthermore, basophils from a healthy non-atopic donor were incubated with participant's sera and histamine release induced by perfume was measured. In both groups incremental perfume concentrations showed a positive and significant (Pperfume concentration, the basophils released significantly (PPerfume induces a dose-dependent non-IgE-mediated release of histamine from human peripheral blood basophils. Increased basophil reactivity to perfume was found in patients with respiratory symptoms related to perfume.

  16. 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.

  17. Nuclear receptor corepressor-dependent repression of peroxisome-proliferator-activated receptor delta-mediated transactivation

    DEFF Research Database (Denmark)

    Krogsdam, Anne-M; Nielsen, Curt A F; Neve, Søren

    2002-01-01

    delta-RXR alpha heterodimer bound to an acyl-CoA oxidase (ACO)-type peroxisome-proliferator response element recruited a glutathione S-transferase-NCoR fusion protein in a ligand-independent manner. Contrasting with most other nuclear receptors, PPAR delta was found to interact equally well......The nuclear receptor corepressor (NCoR) was isolated as a peroxisome-proliferator-activated receptor (PPAR) delta interacting protein using the yeast two-hybrid system. NCoR interacted strongly with the ligand-binding domain of PPAR delta, whereas interactions with the ligand-binding domains...

  18. Scavenger receptor-mediated endocytosis by sinusoidal cells in rat bone marrow

    International Nuclear Information System (INIS)

    Geoffroy, J.S.

    1987-01-01

    Endocytosis of serum albumin by sinusoidal endothelial cells in rat bone marrow was investigated initially at the ultrastructural level with subsequent biochemical investigation of the specificity mediating this event. Bovine serum albumin adsorbed to 20nm colloidal gold particles (AuBSA) was chosen as the electron microscopic probe. Morphological data strongly suggested that a receptor was involved in uptake of AuBSA. Confirmation of receptor involvement in the uptake of AuBSA by marrow sinusoidal endothelial cells was achieved utilizing an in situ isolated hind limb perfusion protocol in conjunction with unlabeled, radiolabeled, and radio-/colloidal gold labeled probes. The major findings of competition and saturation experiments were: (1) endocytosis of AuBSA was mediated by a receptor for modified/treated serum albumin; (2) endocytosis of formaldehyde-treated serum albumin was mediated by a binding site which may be the same or closely related to the site responsible for the uptake of AuBSA; and (3) endocytosis of native untreated albumin was not mediated by receptor and probably represents fluid-phase pinocitosis

  19. VMAT2-mediated neurotransmission from midbrain leptin receptor neurons in feeding regulation

    Science.gov (United States)

    Leptin receptors (LepRs) expressed in the midbrain contribute to the action of leptin on feeding regulation. The midbrain neurons release a variety of neurotransmitters including dopamine (DA), glutamate and GABA. However, which neurotransmitter mediates midbrain leptin action on feeding remains unc...

  20. Cerebellar Kainate Receptor-Mediated Facilitation of Glutamate Release Requires Ca2+-Calmodulin and PKA

    Directory of Open Access Journals (Sweden)

    Rafael Falcón-Moya

    2018-06-01

    Full Text Available We elucidated the mechanisms underlying the kainate receptor (KAR-mediated facilitatory modulation of synaptic transmission in the cerebellum. In cerebellar slices, KA (3 μM increased the amplitude of evoked excitatory postsynaptic currents (eEPSCs at synapses between axon terminals of parallel fibers (PF and Purkinje neurons. KA-mediated facilitation was antagonized by NBQX under condition where AMPA receptors were previously antagonized. Inhibition of protein kinase A (PKA suppressed the effect of KA on glutamate release, which was also obviated by the prior stimulation of adenylyl cyclase (AC. KAR-mediated facilitation of synaptic transmission was prevented by blocking Ca2+ permeant KARs using philanthotoxin. Furthermore, depletion of intracellular Ca2+ stores by thapsigargin, or inhibition of Ca2+-induced Ca2+-release by ryanodine, abrogated the synaptic facilitation by KA. Thus, the KA-mediated modulation was conditional on extracellular Ca2+ entry through Ca2+-permeable KARs, as well as and mobilization of Ca2+ from intracellular stores. Finally, KAR-mediated facilitation was sensitive to calmodulin inhibitors, W-7 and calmidazolium, indicating that the increased cytosolic [Ca2+] sustaining KAR-mediated facilitation of synaptic transmission operates through a downstream Ca2+/calmodulin coupling. We conclude that, at cerebellar parallel fiber-Purkinje cell synapses, presynaptic KARs mediate glutamate release facilitation, and thereby enhance synaptic transmission through Ca2+-calmodulin dependent activation of adenylyl cyclase/cAMP/protein kinase A signaling.

  1. UVB-induced systemic immunosuppression: role of mast cells and histamine

    International Nuclear Information System (INIS)

    Hart, P.H.; Grimbaldeston, M.A.; Finlay-Jones, J.J.

    1999-01-01

    Full text: UVB radiation (290-320 nm) is immunosuppressive by multiple mechanisms allowing the outgrowth of UV-induced tumours in both mouse and man. Furthermore, patients with non-melanoma skin cancers have a higher risk of death from other cancers which could be explained by UV-induced immunomodulation. The mechanism(s) of suppression by UVB depend on whether the sensitising antigen is applied to the irradiated site ('local') or to non-irradiated sites ('systemic'). In the former, the activity of UV-induced TNFα is important as it affects the migration of Langerhans cells to draining lymph nodes. In contrast, histamine from dermal mast cells is critical to the early events by which UVB can suppress systemic immune responses. The prevalence of dermal mast cells in 7 strains and substrains of mice correlates directly with their susceptibility to UVB-induced systemic immunosuppression. Furthermore, mast cell depleted mice (Wf/Wf) are resistant to UVB-induced systemic immunomodulation. However, they become susceptible after reconstitution of the site to be irradiated with bone marrow derived mast cell precursors. The mice also gain susceptibility to cis-urocanic acid-induced systemic immunomodulation. There is considerable evidence that histamine is the mast cell product critical to downstream immunosuppressive events. Firstly, physiological concentrations of histamine suppress contact hypersensitivity responses. Secondly, histamine receptor antagonists halve UVB-induced systemic immunosuppression. Thirdly, mice with different UVB-susceptibilities are equally susceptible to histamine-induced immunosuppression, and finally, histamine can suppress contact hypersensitivity responses in Wf/Wf mice. We suggest that histamine may be immunomodulatory by multiple pathways. Histamine can induce the production of immunosuppressive prostanoids from keratinocytes. A lymphocyte-derived, histamine-induced suppressor factor was reported in the 1970's. More recently histamine has

  2. Glucocorticoid receptor, but not mineralocorticoid receptor, mediates cortisol regulation of epidermal ionocyte development and ion transport in zebrafish (danio rerio.

    Directory of Open Access Journals (Sweden)

    Shelly Abad Cruz

    Full Text Available Cortisol is the major endogenous glucocorticoid (GC both in human and fish, mediated by corticosteroid receptors. Due to the absence of aldosterone production in teleost fish, cortisol is also traditionally accepted to function as mineralocorticoid (MC; but whether it acts through the glucocorticoid receptor (GR or the mineralocorticoid receptor (MR remains a subject of debate. Here, we used loss-of-function and rescue assays to determine whether cortisol affects zebrafish epidermal ionocyte development and function via the GR and/or the MR. GR knockdown morphants displayed a significant decrease in the major ionocytes, namely Na(+-K(+-ATPase-rich cells (NaRCs and H(+-ATPase-rich cells (HRCs, as well as other cells, including epidermal stem cells (ESCs, keratinocytes, and mucus cells; conversely, cell numbers were unaffected in MR knockdown morphants. In agreement, GR morphants, but not MR morphants, exhibited decreased NaRC-mediated Ca(2+ uptake and HRC-mediated H(+ secretion. Rescue via GR capped mRNA injection or exogenous cortisol incubation normalized the number of epidermal ionocytes in GR morphants. We also provide evidence for GR localization in epidermal cells. At the transcript level, GR mRNA is ubiquitously expressed in gill sections and present in both NaRCs and HRCs, supporting the knockdown and functional assay results in embryo. Altogether, we have provided solid molecular evidence that GR is indeed present on ionocytes, where it mediates the effects of cortisol on ionocyte development and function. Hence, cortisol-GR axis performs the roles of both GC and MC in zebrafish skin and gills.

  3. Vascular endothelin ET(B) receptor-mediated contraction requires phosphorylation of ERK1/2 proteins

    DEFF Research Database (Denmark)

    Luo, Guogang; Jamali, Roya; Cao, Yong-Xiao

    2006-01-01

    In cardiovascular diseases, endothelin type B (ET(B)) receptors in arterial smooth muscle cells are upregulated. The present study revealed that organ culture of rat mesenteric artery segments enhanced endothelin ET(B) receptor-mediated contraction paralleled with increase in the receptor mRNA an...

  4. Signaling transduction pathways involved in basophil adhesion and histamine release

    DEFF Research Database (Denmark)

    Sha, Quan; Poulsen, Lars K.; Gerwien, Jens

    2006-01-01

    Little is known about basophil with respect to the different signaling transduction pathways involved in spontaneous, cytokine or anti-IgE induced adhesion and how this compares to IgE-dependent and IgE-independent mediator secretion. The purpose of the present study was to investigate the roles...... of beta1 and beta2 integrins in basophil adhesion as well as hosphatidylinositol 3-kinase (PI3K), src-kinases and extracellular signal regulated kinase (ERK) 1/2 in basophil adhesion and histamine release (HR)....

  5. Staphylococcus aureus and influenza A virus stimulate human bronchoalveolar cells to release histamine and leukotrienes

    DEFF Research Database (Denmark)

    Clementsen, P; Bisgaard, H; Pedersen, M

    1989-01-01

    persons were stimulated with Staph. aureus no release of leukotriene C4 was found. The mediator release caused by bacteria and virus might be of importance for the exacerbation of bronchial asthma in upper respiratory tract infections, since histamine is assumed to increase the epithelial permeability...

  6. The clinical effect of percutaneous histamine on allergic contact dermatitis elicited to fragrance mix

    NARCIS (Netherlands)

    R.L.P. Lijnen; Th. van Joost (Theo)

    1995-01-01

    textabstractHistamine (2-(4-imidazol)ethylamine) has been shown to downregulate cell-mediated reactions in vitro. However, the role of such downregulation in vivo has not yet extensively been studied in humans. In an attempt to gain more insight into this, we studied in vivo the effect of

  7. Simultaneous detection of pH changes and histamine release from oxyntic glands in isolated stomach.

    Science.gov (United States)

    Bitziou, Eleni; O'Hare, Danny; Patel, Bhavik Anil

    2008-11-15

    Real-time simultaneous detection of changes in pH and levels of histamine over the oxyntic glands of guinea pig stomach have been investigated. An iridium oxide pH microelectrode was used in a potentiometric mode to record the pH decrease associated with acid secretion when the sensor approached the isolated tissue. A boron-doped diamond (BDD) microelectrode was used in an amperometric mode to detect histamine when the electrode was placed over the tissue. Both sensors provided stable and reproducible responses that were qualitatively consistent with the signaling mechanism for acid secretion at the stomach. Simultaneous measurements in the presence of pharmacological treatments produced significant variations in the signals obtained by both sensors. As the H2 receptor antagonist cimetidine was perfused to the tissue, histamine levels increased that produced an increase in the signal of the BDD electrode whereas the pH sensor recorded a decrease in acid secretion as expected. Addition of acetylcholine (ACh) stimulated additional acid secretion detected with the pH microelectrode whereas the BDD sensor recorded the histamine levels decreasing significantly. This result shows that the primary influence of ACh is directly on the parietal cell receptors rather then the ECL cell receptors of the oxyntic glands. These results highlight the power of this simultaneous detection technique in the monitoring and diagnosis of physiological significant signaling mechanisms and pathways.

  8. Evidence that 5-hydroxytryptamine3 receptors mediate cytotoxic drug and radiation-evoked emesis

    International Nuclear Information System (INIS)

    Miner, W.D.; Sanger, G.J.; Turner, D.H.

    1987-01-01

    The involvement of 5-hydroxytryptamine (5-HT) 5-HT 3 receptors in the mechanisms of severe emesis evoked by cytotoxic drugs or by total body irradiation have been studied in ferrets. Anti-emetic compounds tested were domperidone (a dopamine antagonist), metoclopramide (a gastric motility stimulant and dopamine antagonist at conventional doses, a 5-HT 3 receptor antagonist at higher doses) and BRL 24924 (a potent gastric motility stimulant and a 5-HT 3 receptor antagonist). Domperidone or metoclopramide prevented apomorphine-evoked emesis, whereas BRL 24924 did not. Similar doses of domperidone did not prevent emesis evoked by cis-platin or by total body irradiation, whereas metoclopramide or BRL 24924 greatly reduced or prevented these types of emesis. Metoclopramide and BRL 24924 also prevented emesis evoked by a combination of doxorubicin and cyclophosphamide. These results are discussed in terms of a fundamental role for 5-HT 3 receptors in the mechanisms mediating severely emetogenic cancer treatment therapies. (author)

  9. Effects of sarcosine and N, N-dimethylglycine on NMDA receptor-mediated excitatory field potentials.

    Science.gov (United States)

    Lee, Mei-Yi; Lin, Yi-Ruu; Tu, Yi-Shu; Tseng, Yufeng Jane; Chan, Ming-Huan; Chen, Hwei-Hsien

    2017-02-28

    Sarcosine, a glycine transporter type 1 inhibitor and an N-methyl-D-aspartate (NMDA) receptor co-agonist at the glycine binding site, potentiates NMDA receptor function. Structurally similar to sarcosine, N,N-dimethylglycine (DMG) is also N-methyl glycine-derivative amino acid and commonly used as a dietary supplement. The present study compared the effects of sarcosine and DMG on NMDA receptor-mediated excitatory field potentials (EFPs) in mouse medial prefrontal cortex brain slices using a multi-electrode array system. Glycine, sarcosine and DMG alone did not alter the NMDA receptor-mediated EFPs, but in combination with glutamate, glycine and its N-methyl derivatives significantly increased the frequency and amplitude of EFPs. The enhancing effects of glycine analogs in combination with glutamate on EFPs were remarkably reduced by the glycine binding site antagonist 7-chlorokynurenate (7-CK). However, DMG, but not sarcosine, reduced the frequency and amplitude of EFPs elicited by co-application of glutamate plus glycine. D-cycloserine, a partial agonist at the glycine binding site on NMDA receptors, affected EFPs in a similar manner to DMG. Furthermore, DMG, but not sarcosine, reduced the frequencies and amplitudes of EFPs elicited by glutamate plus D-serine, another endogenous ligand for glycine binding site. These findings suggest that sarcosine acts as a full agonist, yet DMG is a partial agonist at glycine binding site of NMDA receptors. The molecular docking analysis indicated that the interactions of glycine, sarcosine, and DMG to NMDA receptors are highly similar, supporting that the glycine binding site of NMDA receptors is a critical target site for sarcosine and DMG.

  10. Receptor-mediated targeting of 67Ga-Deferoxamine-Folate to folate-receptor-positive human kb tumor xenografts

    International Nuclear Information System (INIS)

    Mathias, Carla J.; Wang, Susan; Low, Philip S.; Waters, David J.; Green, Mark A.

    1999-01-01

    The radiochemical synthesis and stability of 67 Ga-deferoxamine-folate ([ 67 Ga]Ga-DF-Folate) were examined as a function of DF-Folate concentration. Optimal labeling occurred at DF-Folate concentrations ≥2.5 μg/mL. To define the possible biological significance of variations in product formulation, the biodistribution of [ 67 Ga]Ga-DF-Folate was examined as a function of administered deferoxamine-folate dose in an athymic mouse KB tumor model. The folate-receptor-positive KB tumors were found to concentrate the 67 Ga radiolabel in a dose-dependent fashion, consistent with saturable involvement of the folate receptor in mediating tumor accumulation of the radiopharmaceutical

  11. P2X receptor-mediated ATP purinergic signaling in health and disease

    Directory of Open Access Journals (Sweden)

    Jiang LH

    2012-09-01

    Full Text Available Lin-Hua JiangSchool of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United KingdomAbstract: Purinergic P2X receptors are plasma membrane proteins present in a wide range of mammalian cells where they act as a cellular sensor, enabling cells to detect and respond to extracellular adenosine triphosphate (ATP, an important signaling molecule. P2X receptors function as ligand-gated Ca2+-permeable cationic channels that open upon ATP binding to elevate intracellular Ca2+ concentrations and cause membrane depolarization. In response to sustained activation, P2X receptors induce formation of a pore permeable to large molecules. P2X receptors also interact with distinct functional proteins and membrane lipids to form specialized signaling complexes. Studies have provided compelling evidence to show that such P2X receptor-mediated ATP-signaling mechanisms determine and regulate a growing number and diversity of important physiological processes, including neurotransmission, muscle contraction, and cytokine release. There is accumulating evidence to support strong causative relationships of altered receptor expression and function with chronic pain, inflammatory diseases, cancers, and other pathologies or diseases. Numerous high throughput screening drug discovery programs and preclinical studies have thus far demonstrated the proof of concepts that the P2X receptors are druggable targets and selective receptor antagonism is a promising therapeutics approach. This review will discuss the recent progress in understanding the mammalian P2X receptors with respect to the ATP-signaling mechanisms, physiological and pathophysiological roles, and development and preclinical studies of receptor antagonists.Keywords: extracellular ATP, ion channel, large pore, signaling complex, chronic pain, inflammatory diseases

  12. The TIM and TAM families of phosphatidylserine receptors mediate dengue virus entry.

    Science.gov (United States)

    Meertens, Laurent; Carnec, Xavier; Lecoin, Manuel Perera; Ramdasi, Rasika; Guivel-Benhassine, Florence; Lew, Erin; Lemke, Greg; Schwartz, Olivier; Amara, Ali

    2012-10-18

    Dengue viruses (DVs) are responsible for the most medically relevant arboviral diseases. However, the molecular interactions mediating DV entry are poorly understood. We determined that TIM and TAM proteins, two receptor families that mediate the phosphatidylserine (PtdSer)-dependent phagocytic removal of apoptotic cells, serve as DV entry factors. Cells poorly susceptible to DV are robustly infected after ectopic expression of TIM or TAM receptors. Conversely, DV infection of susceptible cells is inhibited by anti-TIM or anti-TAM antibodies or knockdown of TIM and TAM expression. TIM receptors facilitate DV entry by directly interacting with virion-associated PtdSer. TAM-mediated infection relies on indirect DV recognition, in which the TAM ligand Gas6 acts as a bridging molecule by binding to PtdSer within the virion. This dual mode of virus recognition by TIM and TAM receptors reveals how DVs usurp the apoptotic cell clearance pathway for infectious entry. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Adenosine: a putative mediator of bronchoconstriction in asthma

    Energy Technology Data Exchange (ETDEWEB)

    Mann, J.S.

    1987-01-01

    The protective effect of a muscarinic cholinergic antagonists, ipratropium bromide (IB) from inhaled adenosine- and methacholine-induced bronchoconstriction in asthma was studied. Inhaled IB protected from methacholine- but not adenosine-induced bronchoconstriction. Parasympathetically mediated bronchoconstriction is therefore unlikely to account for adenosine's airway effect in asthma. The capacity of theophylline, a bronchodilator and a competitive antagonist of adenosine at its cell surface receptors, to protect asthmatic subjects from adenosine- and histamine-induced bronchoconstriction was determined. Asthmatic airways are infiltrated with inflammatory cells. Human leucocytes prelabeled with (/sup 3/H)-adenine when activated with the calcium ionophore A23187 released labelled hypoxanthine, inosine and adenosine which was associated with a dose-related release of histamine. The chemotactic peptide f-MLP while inducing histamine release had an inconstant effect on release of label. In four of five experiments f-MLP produced a transient early increase in label release but in the remaining experiment no significant release was observed. Anti-human IgE failed to induce significant label release despite releasing histamine. Activated leucocytes are therefore a potential source of adenosine in asthma.

  14. Adrenergic receptor-mediated modulation of striatal firing patterns.

    Science.gov (United States)

    Ohta, Hiroyuki; Kohno, Yu; Arake, Masashi; Tamura, Risa; Yukawa, Suguru; Sato, Yoshiaki; Morimoto, Yuji; Nishida, Yasuhiro; Yawo, Hiromu

    2016-11-01

    Although noradrenaline and adrenaline are some of the most important neurotransmitters in the central nervous system, the effects of noradrenergic/adrenergic modulation on the striatum have not been determined. In order to explore the effects of adrenergic receptor (AR) agonists on the striatal firing patterns, we used optogenetic methods which can induce continuous firings. We employed transgenic rats expressing channelrhodopsin-2 (ChR2) in neurons. The medium spiny neuron showed a slow rising depolarization during the 1-s long optogenetic striatal photostimulation and a residual potential with 8.6-s half-life decay after the photostimulation. As a result of the residual potential, five repetitive 1-sec long photostimulations with 20-s onset intervals cumulatively increased the number of spikes. This 'firing increment', possibly relating to the timing control function of the striatum, was used to evaluate the AR modulation. The β-AR agonist isoproterenol decreased the firing increment between the 1st and 5th stimulation cycles, while the α 1 -AR agonist phenylephrine enhanced the firing increment. Isoproterenol and adrenaline increased the early phase (0-0.5s of the photostimulation) firing response. This adrenergic modulation was inhibited by the β-antagonist propranolol. Conversely, phenylephrine and noradrenaline reduced the early phase response. β-ARs and α 1 -ARs work in opposition controlling the striatal firing initiation and the firing increment. Copyright © 2016 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

  15. Dopamine D3 receptors mediate the discriminative stimulus effects of quinpirole in free-feeding rats.

    Science.gov (United States)

    Baladi, Michelle G; Newman, Amy H; France, Charles P

    2010-01-01

    The discriminative stimulus effects of dopamine (DA) D3/D2 receptor agonists are thought to be mediated by D2 receptors. To maintain responding, access to food is often restricted, which can alter neurochemical and behavioral effects of drugs acting on DA systems. This study established stimulus control with quinpirole in free-feeding rats and tested the ability of agonists to mimic and antagonists to attenuate the effects of quinpirole. The same antagonists were studied for their ability to attenuate quinpirole-induced yawning and hypothermia. DA receptor agonists apomorphine and lisuride, but not amphetamine and morphine, occasioned responding on the quinpirole lever. The discriminative stimulus effects of quinpirole were attenuated by the D3 receptor-selective antagonist N-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]-trans-but-2-enyl}-4-pyridine-2-yl-benzamide HCl (PG01037) and the nonselective D3/D2 receptor antagonist raclopride, but not by the D2 receptor-selective antagonist 3-[4-(4-chlorophenyl)-4-hydroxypiperidin-1-yl]methyl-1H-indole (L-741,626); the potencies of PG01037 and raclopride to antagonize this effect of quinpirole paralleled their potencies to antagonize the ascending limb of the quinpirole yawning dose-response curve (thought to be mediated by D3 receptors). L-741,626 selectively antagonized the descending limb of the quinpirole yawning dose-response curve, and both L-741,626 and raclopride, but not PG01037, antagonized the hypothermic effects of quinpirole (thought to be mediated by D2 receptors). Food restriction (10 g/day/7 days) significantly decreased quinpirole-induced yawning without affecting the quinpirole discrimination. Many discrimination studies on DA receptor agonists use food-restricted rats; together with those studies, the current experiment using free-feeding rats suggests that feeding conditions affecting the behavioral effects of direct-acting DA receptor agonists might also have an impact on the effects of indirect

  16. H1 antihistamines in allergic rhinitis: The molecular pathways of interleukin and toll - like receptor systems

    Directory of Open Access Journals (Sweden)

    Jonny Karunia Fajar

    2016-03-01

    Full Text Available The complex interaction between inflammatory mediators in allergic rhinitis (AR is determined by the role of genetic polymorphisms, including interleukin (IL and toll-like receptor (TLR genes. This study aimed to discuss the effects of H1-antihistamines on IL and TLR systems. Several ILs involved in AR pathogenesis are: IL-4 (rs2243250, rs1800925, rs1801275, rs2227284, rs2070874, IL-6 (rs1800795, rs1800797, IL-10 (rs1800871, rs1800872, IL-12R (rs438421, IL-13 (rs1800925, rs20541, IL-17 (rs3819024, IL-18 (rs360721, rs360718, rs360717, rs187238, IL-23R (rs7517847, and IL-27 (rs153109, rs17855750. In the IL system, histamines stimulate the IL production in Type 2 helper T (Th2 cells through protein kinase A (PKA, janus kinase-signal transducer and activator of transcription (JAK-STAT pathway, and the activation of H1-histamine receptor and histidine decarboxylase (HDC genes. On contrary, antihistamines down-regulate the H1-histamine receptor gene expression through the transcription suppression of HDC and IL genes and suppress histamine basal signaling through the inverse agonistic activity. TLRs involved in AR pathogenesis are TLR2 (rs4696480, rs3804099, rs5743708, TLR4 (rs4986790, TLR6 (rs2381289, TLR7 (rs179008, rs5935438, TRL8 (rs2407992, rs5741883, rs17256081, rs4830805, rs3788935, rs178998, and TLR10 (rs11466651. In the TLR system, histamines trigger the TLR expression by stimulating interferon-γ (IFN-γ to up-regulate mast cells and by stimulating receptor-interacting protein (RIP to activate IκB kinase-β. Contrastingly, antihistamines suppress TIR-domain-containing adaptor protein inducing IFN-β (TRIF and RIP protein and thus inhibit the expression of TLR. In addition, several studies indicated that H1-antihistamines inhibit the IL and TLR systems indirectly.

  17. Basolateral P2X receptors mediate inhibition of NaCl transport in mouse medullary thick ascending limb (mTAL)

    DEFF Research Database (Denmark)

    Marques, Rita D; de Bruijn, Pauline I.A.; Sørensen, Mads Vaarby

    2012-01-01

    Extracellular nucleotides regulate epithelial transport via luminal and basolateral P2 receptors. Renal epithelia express multiple P2 receptors, which mediate significant inhibition of solute absorption. Recently, we identified several P2 receptors in the medullary thick ascending limb (m...

  18. Studies on the role of central histamine in the acquisition of a radiation-induced conditioned taste aversion

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1982-01-01

    The experiments described in this report were designed to test two hypotheses about how exposure to low-level radiation can affect the behavior of an organism: first, tht radiation effects on behavior are mediated by a radiation-induced release of histamine; and second, that this radiation-induced histamine release can exert relatively direct effects on the central nervous system. The results of the first experiment showed that microinjection of histamine directly into the fourth ventricle of rats produced a taste aversion to a novel sucrose solution. Pretreating rats with intraventricular H 1 or H 2 blockers was not effective in preventing the acquisition of the radiation-induced aversion, although the H 1 blocker did prevent the acquisition of a histamine-induced taste aversion. It also was not possible to establish a cross-tolerance between centrally administered histamine and radiation. The results are interpreted as not supporting the hypothesis that a radiation-induced release of central histamine mediates the acquisition of a conditioned taste aversion following exposure to low-level radiation

  19. Utilization of Diamine Oxidase Enzyme from Mung Bean Sprouts (Vigna radiata L) for Histamine biosensors

    Science.gov (United States)

    Karim, Abdul; Wahab, A. W.; Raya, I.; Natsir, H.; Arif, A. R.

    2018-03-01

    This research is aimed to utilize the diamine oxidase enzyme (DAO) which isolated from mung bean sprouts (Vigna radiata L) to develop histamine biosensors based on electode enzyme with the amperometric method (cyclic voltammetry).The DAO enzyme is trapped inside the membrane of chitin-cellulose acetate 2:1 and glutaraldehyde which super imposed on a Pt electrode. Histamine will be oxidized by DAO enzyme to produce aldehydes and H2O2 that acting as electron transfer mediators.The performance of biosensors will be measured at various concentrations of glutaraldehyde, temperature changes and different range of pH. Recently, it has been found that the optimal conditions obtained from the paramaters as follows; at 25% of glutaraldehyde, temperature of 37°C and pH of 7.4. Eventually, the results provided an expectation for applying histamine biosensors in determining the freshness and safety of fish specifically skombroidae families.

  20. Increased release of histamine in patients with respiratory symptoms related to perfume

    DEFF Research Database (Denmark)

    Elberling, J; Skov, P S; Mosbech, H

    2007-01-01

    BACKGROUND: Environmental perfume exposure may cause respiratory symptoms. Individuals with asthma and perfume contact allergy report such symptoms more frequently than others. However, immunologic mechanisms have not been demonstrated and the symptoms are not associated with IgE-mediated allergy....... The study aimed to investigate whether basophils from patients with respiratory symptoms related to perfume released more histamine in the presence of perfume as compared with healthy volunteers. METHODS: Histamine release was measured by the glass fibre method. Blood was obtained from healthy volunteers (n......=20) and patients with respiratory symptoms related to perfume (n=17) attending a dermatological outpatient clinic for patch testing. The effect of an international brand perfume was investigated using the basophil histamine release test with perfume. Furthermore, basophils from a healthy non...

  1. Role of histamine in the inhibitory effects of phycocyanin in experimental models of allergic inflammatory response

    Directory of Open Access Journals (Sweden)

    D. Remirez

    2002-01-01

    Full Text Available It has recently been reported that phycocyanin, a biliprotein found in the blue-green microalgae Spirulina, exerts anti-inflammatory effects in some animal models of inflammation. Taking into account these findings, we decided to elucidate whether phycocyanin might exert also inhibitory effects in the induced allergic inflammatory response and on histamine release from isolated rat mast cells. In in vivo experiments, phycocyanin (100, 200 and 300 mg/kg post-orally (p.o. was administered 1 h before the challenge with 1 μg of ovalbumin (OA in the ear of mice previously sensitized with OA. One hour later, myeloperoxidase activity and ear edema were assessed. Phycocyanin significantly reduced both parameters. In separate experiments, phycocyanin (100 and 200 mg/kg p.o. also reduced the blue spot area induced by intradermal injections of histamine, and the histamine releaser compound 48/80 in rat skin. In concordance with the former results, phyco-cyanin also significantly reduced histamine release induced by compound 48/80 from isolated peritoneal rat mast cells. The inhibitory effects of phycocyanin were dose dependent. Taken together, our results suggest that inhibition of allergic inflammatory response by phycocyanin is mediated, at least in part, by inhibition of histamine release from mast cells.

  2. Receptor-Mediated Drug Delivery to Macrophages in Chemotherapy of Leishmaniasis

    Science.gov (United States)

    Mukhopadhyay, Amitabha; Chaudhuri, Gautam; Arora, Sunil K.; Sehgal, Shobha; Basu, Sandip K.

    1989-05-01

    Methotrexate coupled to maleylated bovine serum albumin was taken up efficiently through the ``scavenger'' receptors present on macrophages and led to selective killing of intracellular Leishmania mexicana amazonensis amastigotes in cultured hamster peritoneal macrophages. The drug conjugate was nearly 100 times as effective as free methotrexate in eliminating the intracellular parasites. Furthermore, in a model of experimental cutaneous leishmaniasis in hamsters, the drug conjugate brought about more than 90% reduction in the size of footpad lesions within 11 days. In contrast, the free drug at a similar concentration did not significantly affect lesion size. These studies demonstrate the potential of receptor-mediated drug delivery in the therapy of macrophage-associated diseases.

  3. Mediator and p300/CBP-Steroid Receptor Coactivator Complexes Have Distinct Roles, but Function Synergistically, during Estrogen Receptor α-Dependent Transcription with Chromatin Templates

    OpenAIRE

    Acevedo, Mari Luz; Kraus, W. Lee

    2003-01-01

    Ligand-dependent transcriptional activation by nuclear receptors involves the recruitment of various coactivators to the promoters of hormone-regulated genes assembled into chromatin. Nuclear receptor coactivators include histone acetyltransferase complexes, such as p300/CBP-steroid receptor coactivator (SRC), as well as the multisubunit mediator complexes (“Mediator”), which may help recruit RNA polymerase II to the promoter. We have used a biochemical approach, including an in vitro chromat...

  4. Interaction of medullary P2 and glutamate receptors mediates the vasodilation in the hindlimb of rat.

    Science.gov (United States)

    Korim, Willian Seiji; Ferreira-Neto, Marcos L; Pedrino, Gustavo R; Pilowsky, Paul M; Cravo, Sergio L

    2012-12-01

    In the nucleus tractus solitarii (NTS) of rats, blockade of extracellular ATP breakdown to adenosine reduces arterial blood pressure (AP) increases that follow stimulation of the hypothalamic defense area (HDA). The effects of ATP on NTS P2 receptors, during stimulation of the HDA, are still unclear. The aim of this study was to determine whether activation of P2 receptors in the NTS mediates cardiovascular responses to HDA stimulation. Further investigation was taken to establish if changes in hindlimb vascular conductance (HVC) elicited by electrical stimulation of the HDA, or activation of P2 receptors in the NTS, are relayed in the rostral ventrolateral medulla (RVLM); and if those responses depend on glutamate release by ATP acting on presynaptic terminals. In anesthetized and paralyzed rats, electrical stimulation of the HDA increased AP and HVC. Blockade of P2 or glutamate receptors in the NTS, with bilateral microinjections of suramin (10 mM) or kynurenate (50 mM) reduced only the evoked increase in HVC by 75 % or more. Similar results were obtained with the blockade combining both antagonists. Blockade of P2 and glutamate receptors in the RVLM also reduced the increases in HVC to stimulation of the HDA by up to 75 %. Bilateral microinjections of kynurenate in the RVLM abolished changes in AP and HVC to injections of the P2 receptor agonist α,β-methylene ATP (20 mM) into the NTS. The findings suggest that HDA-NTS-RVLM pathways in control of HVC are mediated by activation of P2 and glutamate receptors in the brainstem in alerting-defense reactions.

  5. Induction of osteoblast differentiation by selective activation of kinase-mediated actions of the estrogen receptor.

    Science.gov (United States)

    Kousteni, Stavroula; Almeida, Maria; Han, Li; Bellido, Teresita; Jilka, Robert L; Manolagas, Stavros C

    2007-02-01

    Estrogens control gene transcription by cis or trans interactions of the estrogen receptor (ER) with target DNA or via the activation of cytoplasmic kinases. We report that selective activation of kinase-mediated actions of the ER with 4-estren-3alpha,17beta-diol (estren) or an estradiol-dendrimer conjugate, each a synthetic compound that stimulates kinase-mediated ER actions 1,000 to 10,000 times more potently than direct DNA interactions, induced osteoblastic differentiation in established cell lines of uncommitted osteoblast precursors and primary cultures of osteoblast progenitors by stimulating Wnt and BMP-2 signaling in a kinase-dependent manner. In sharp contrast, 17beta-estradiol (E(2)) suppressed BMP-2-induced osteoblast progenitor commitment and differentiation. Consistent with the in vitro findings, estren, but not E(2), stimulated Wnt/beta-catenin-mediated transcription in T-cell factor-lacZ transgenic mice. Moreover, E(2) stimulated BMP signaling in mice in which ERalpha lacks DNA binding activity and classical estrogen response element-mediated transcription (ERalpha(NERKI/-)) but not in wild-type controls. This evidence reveals for the first time the existence of a large signalosome in which inputs from the ER, kinases, bone morphogenetic proteins, and Wnt signaling converge to induce differentiation of osteoblast precursors. ER can either induce it or repress it, depending on whether the activating ligand (and presumably the resulting conformation of the receptor protein) precludes or accommodates ERE-mediated transcription.

  6. The Role of Estrogen Related Receptor in Modulating Estrogen Receptor Mediated Transcription in Breast Cancer Cells

    Science.gov (United States)

    2005-04-01

    tumors correlates with an unfavorable prognosis (Ariazi 2002; Lu 2001; Suzuki 2004; Vanacker 1999). The transcriptional activity of ERRa is not inhibited...SA. 101:6570-5. Needham, M ., S. Raines, J. McPheat, C. Stacey, J. Ellston, S. Hoare, and M . Parker. 2000. Differential interaction of steroid hormone...R. Graves, M . Wright, and B.M. Spiegelman. 1998. A cold- inducible coactivator of nuclear receptors linked to adaptive thermogenesis. Cell. 92:829- 39

  7. Antitumor effects of radioiodinated antisense oligonucleotide mediated by VIP receptor

    International Nuclear Information System (INIS)

    Ou Xiaohong; Tan Tianzhi; Li Yunchun; Kuang Anren

    2004-01-01

    Purpose: we had constructed a targeting delivery system based on intestinal peptide (VIP) for antisense oligonucleotide (ASON) transfer into VIP receptor-positive cells in previous study. The aims of present studies are to observe the antitumor effect of VIP-131I-ASON in HT29 human colon adenocarcinoma xenografts. Methods: A 15-met phosphorothioate ASON, which was complementary to the translation start region of the C-myc oncogene mRNA, was labeled with 131I and the labelled compound was linked to the VIP bound covalently 'to a polylysine chain so as to deliver oligonucleotide into tumor cells. Distribution experiments for evaluating the radiolabeled antisense complexe uptake in tumor tissue were performed in BALB/c nude mice bearing with HT29 tumor xenografts. Nude mice beating HT29 tumor xenografts were adminstered VIP-131I-ASON (3.7,7.4 MBq) or 131I-ASON (3.7 MBq), 131I labeled control sense and nosense DNA (3.7 MBq), or saline. Antitumor effects were assessed using endpoints of tumor growth delay. C-myc-encoded protein expression of tumor was measured by immunocytohistochemical staining. Results: Distribution experiment performed with athymic mice bearing human colon tumor xenografts revealed maximal accumulation of conjugated ASON in the tumor tissue 2 h after administration and significantly higher than that in nude mice injected unconjngated ASON [(5.89±1.03)%ID/g and(1.56±0.31)%ID/g, respectively; t=7.7954 P<0.001]. The radioratio of tumor to muscle was peaked 4h after administration. VIP-131I-ASON exhibited strong antitumor effects against HT29 xenografts, decreasing their growth rate 7-fold compare with that in saline-treated mice(tumor growth delay, 25.4±0.89 day). The antitumor effects of unconjugated 131I-ASON were much less profound than VIP-131I-ASON (tumor growth delay, 3.2±1.3 and 25.4±0.89 day, respectively; q=51.4126 P<0.01). Sense, nosense control ON with VIP carder caused no therapeutic effect. There was no progressive weight loss or

  8. Phytomelatonin receptor PMTR1-mediated signaling regulates stomatal closure in Arabidopsis thaliana.

    Science.gov (United States)

    Wei, Jian; Li, Dong-Xu; Zhang, Jia-Rong; Shan, Chi; Rengel, Zed; Song, Zhong-Bang; Chen, Qi

    2018-04-27

    Melatonin has been detected in plants in 1995; however, the function and signaling pathway of this putative phytohormone are largely undetermined due to a lack of knowledge about its receptor. Here, we discovered the first phytomelatonin receptor (CAND2/PMTR1) in Arabidopsis thaliana and found that melatonin governs the receptor-dependent stomatal closure. The application of melatonin induced stomatal closure through the heterotrimeric G protein α subunit-regulated H 2 O 2 and Ca 2+ signals. The Arabidopsis mutant lines lacking AtCand2 that encodes a candidate G protein-coupled receptor were insensitive to melatonin-induced stomatal closure. Accordingly, the melatonin-induced H 2 O 2 production and Ca 2+ influx were completely abolished in cand2. CAND2 is a membrane protein that interacts with GPA1 and the expression of AtCand2 was tightly regulated by melatonin in various organs and guard cells. CAND2 showed saturable and specific 125 I-melatonin binding, with apparent K d (dissociation constant) of 0.73 ± 0.10 nmol/L (r 2  = .99), demonstrating this protein is a phytomelatonin receptor (PMTR1). Our results suggest that the phytomelatonin regulation of stomatal closure is dependent on its receptor CAND2/PMTR1-mediated H 2 O 2 and Ca 2+ signaling transduction cascade. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Proteinase-activated receptors - mediators of early and delayed normal tissue radiation responses

    International Nuclear Information System (INIS)

    Hauer-Jensen, M.

    2003-01-01

    Proteinase-activated receptors (PARs) are G-protein coupled receptors that are activated by proteolytic exposure of a receptor-tethered ligand. The discovery of this receptor family represents one of the most intriguing recent developments in signal transduction. PARs are involved in the regulation of many normal and pathophysiological processes, notably inflammatory and fibroproliferative responses to injury. Preclinical studies performed in our laboratory suggest that proteinase-activated receptor-1 (PAR-1) plays a critical role in the mechanism of chronicity of radiation fibrosis, while proteinase-activated receptor-2 (PAR-2) may mediate important fibroproliferative responses in irradiated intestine. Specifically, activation of PAR-1 by thrombin, and PAR-2 by pancreatic trypsin and mast cell proteinases, appears to be involved in acute radiation-induced inflammation, as well as in subsequent extracellular matrix deposition, leading to the development of intestinal wall fibrosis and clinical complications. Pharmacological modulators of PAR-1 or PAR-2 expression or activation would be potentially useful as preventive or therapeutic agents in patients who receive radiation therapy, especially if blockade could be targeted to specific tissues or cellular compartments

  10. TRPM8 mediates cold and menthol allergies associated with mast cell activation.

    Science.gov (United States)

    Cho, Yeongyo; Jang, Yongwoo; Yang, Young Duk; Lee, Chang-Hun; Lee, Yunjong; Oh, Uhtaek

    2010-10-01

    Exposure to low temperatures often causes allergic responses or urticaria. Similarly, menthol, a common food additive is also known to cause urticaria, asthma, and rhinitis. However, despite the obvious clinical implications, the molecular mechanisms responsible for inducing allergic responses to low temperatures and menthol have not been determined. Because a non-selective cation channel, transient receptor potential subtype M8 (TRPM8) is activated by cold and menthol, we hypothesized that this channel mediates cold- and menthol-induced histamine release in mast cells. Here, we report that TRPM8 is expressed in the basophilic leukemia mast cell line, RBL-2H3, and that exposure to menthol or low temperatures induced Ca(2+) influx in RBL-2H3 cells, which was reversed by a TRPM8 blocker. Furthermore, menthol, a TRPM8 agonist, induced the dose-dependent release of histamine from RBL-2H3 cells. When TRPM8 transcripts were reduced by siRNA (small interfering RNA), menthol- and cold-induced Ca(2+) influx and histamine release were significantly reduced. In addition, subcutaneous injection of menthol evoked scratching, a typical histamine-induced response which was reversed by a TRPM8 blocker. Thus, our findings indicate that TRPM8 mediates the menthol- and cold-induced allergic responses of mast cells, and suggest that TRPM8 antagonists be viewed as potential treatments for cold- and menthol-induced allergies. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. THIP, a hypnotic and antinociceptive drug, enhances a tonic GABAA receptor mediated conductance in mouse neocortex

    DEFF Research Database (Denmark)

    Drasbek, Kim Ryun; Jensen, Kimmo

    2006-01-01

    its cellular actions in the neocortex are uncertain, we studied the effects of THIP on neurons in slices of frontoparietal neocortex of 13- to 19-day-old (P13-19) mice. Using whole-cell patch-clamp recordings, we found that the clinically relevant THIP concentration of 1 μM induced a robust tonic GABA...... suggest that THIP activates an extrasynaptic GABA(A) receptor-mediated conductance in the neocortex, which may alter the cortical network activity....

  12. Neuropeptide Y restores non-receptor-mediated vasoconstrictive action in superior mesenteric arteries in portal hypertension.

    Science.gov (United States)

    Hartl, Johannes; Dietrich, Peter; Moleda, Lukas; Müller-Schilling, Martina; Wiest, Reiner

    2015-12-01

    Vascular hyporeactivity to vasoconstrictors contributes to splanchnic arterial vasodilatation and hemodynamic dysregulation in portal hypertension. Neuropeptide Y (NPY), a sympathetic cotransmitter, has been shown to improve adrenergic vascular contractility in portal hypertensive rats and markedly attenuate hyperdynamic circulation. To further characterize the NPY-effects in portal hypertension, we investigated its role for non-receptor-mediated vasoconstriction in the superior mesenteric artery (SMA) of portal vein ligated (PVL) and sham-operated rats. Ex vivo SMA perfusion of PVL and sham rats was used to analyse the effects of NPY on pressure response to non-receptor-mediated vasoconstriction. Dose-response curves to KCl (30-300 mM) were used to bypass G protein-coupled receptor mechanisms. Potential involvement of the cyclooxygenase-pathway was tested by non-selective cyclooxygenase-inhibition using indomethacin. KCl-induced vascular contractility but not vascular sensitivity was significantly attenuated in PVL rats as compared with sham rats. Administration of NPY resulted in an augmentation of KCl-evoked vascular sensitivity being not different between study groups. However, KCl-induced vascular contractility was markedly more enhanced in PVL rats, thus, vascular response was no more significantly different between PVL and sham rats after addition of NPY. Administration of indomethacin abolished the NPY-induced enhancement of vasoconstriction. Receptor-independent vascular contractility is impaired in mesenteric arteries in portal hypertension. NPY improves non-receptor mediated mesenteric vasoconstriction more effective in portal hypertension than in healthy conditions correcting splanchnic vascular hyporesponsiveness. This beneficial vasoactive action of NPY adds to its well known more pronounced effects on adrenergic vasoconstriction in portal hypertension making it a promising therapeutic agent in portal hypertension. © 2015 John Wiley & Sons A

  13. Receptor-mediated uptake of low density lipoprotein stimulates bile acid synthesis by cultured rat hepatocytes

    International Nuclear Information System (INIS)

    Junker, L.H.; Davis, R.A.

    1989-01-01

    The cellular mechanisms responsible for the lipoprotein-mediated stimulation of bile acid synthesis in cultured rat hepatocytes were investigated. Adding 280 micrograms/ml of cholesterol in the form of human or rat low density lipoprotein (LDL) to the culture medium increased bile acid synthesis by 1.8- and 1.6-fold, respectively. As a result of the uptake of LDL, the synthesis of [14C]cholesterol from [2-14C]acetate was decreased and cellular cholesteryl ester mass was increased. Further studies demonstrated that rat apoE-free LDL and apoE-rich high density lipoprotein (HDL) both stimulated bile acid synthesis 1.5-fold, as well as inhibited the formation of [14C]cholesterol from [2-14C]acetate. Reductive methylation of LDL blocked the inhibition of cholesterol synthesis, as well as the stimulation of bile acid synthesis, suggesting that these processes require receptor-mediated uptake. To identify the receptors responsible, competitive binding studies using 125I-labeled apoE-free LDL and 125I-labeled apoE-rich HDL were performed. Both apoE-free LDL and apoE-rich HDL displayed an equal ability to compete for binding of the other, suggesting that a receptor or a group of receptors that recognizes both apolipoproteins is involved. Additional studies show that hepatocytes from cholestyramine-treated rats displayed 2.2- and 3.4-fold increases in the binding of apoE-free LDL and apoE-rich HDL, respectively. These data show for the first time that receptor-mediated uptake of LDL by the liver is intimately linked to processes activating bile acid synthesis

  14. Glutamate AMPA/kainate receptors, not GABA(A) receptors, mediate estradiol-induced sex differences in the hypothalamus.

    Science.gov (United States)

    Todd, Brigitte J; Schwarz, Jaclyn M; Mong, Jessica A; McCarthy, Margaret M

    2007-02-15

    Sex differences in brain morphology underlie physiological and behavioral differences between males and females. During the critical perinatal period for sexual differentiation in the rat, gonadal steroids act in a regionally specific manner to alter neuronal morphology. Using Golgi-Cox impregnation, we examined several parameters of neuronal morphology in postnatal day 2 (PN2) rats. We found that in the ventromedial nucleus of the hypothalamus (VMN) and in areas just dorsal and just lateral to the VMN that there was a sex difference in total dendritic spine number (males greater) that was abolished by treating female neonates with exogenous testosterone. Dendritic branching was similarly sexually differentiated and hormonally modulated in the VMN and dorsal to the VMN. We then used spinophilin, a protein that positively correlates with the amount of dendritic spines, to investigate the mechanisms underlying these sex differences. Estradiol, which mediates most aspects of masculinization and is the aromatized product of testosterone, increased spinophilin levels in female PN2 rats to that of males. Muscimol, an agonist at GABA(A) receptors, did not affect spinophilin protein levels in either male or female neonates. Kainic acid, an agonist at glutamatergic AMPA/kainate receptors, mimicked the effect of estradiol in females. Antagonizing AMPA/kainate receptors with NBQX prevented the estradiol-induced increase in spinophilin in females but did not affect spinophilin level in males. (c) 2007 Wiley Periodicals, Inc.

  15. The Role of PPAR Receptors and Leukotriene B4 Receptors in Mediating the Effects of LY293111 in Pancreatic Cancer

    Directory of Open Access Journals (Sweden)

    Thomas E. Adrian

    2008-01-01

    Full Text Available Pancreatic cancer is a devastating disease in which current therapies are inadequate. Separate lines of research have identified the 5-lipoxygenase/leukotriene B4 receptor pathway and the PPAR pathway as potential targets for prevention or treatment of this disease. LY293111 was originally designed as a potent leukotriene B4 receptor antagonist for treatment of inflammatory conditions. LY293111 was also known to have inhibitory effects on 5-lipoxygenase, which is upstream of the production of leukotrienes. LY293111 was shown to have potent anticancer effects in pancreatic cancer and several other solid malignancies, where it caused cell cycle arrest and marked apoptosis. Subsequently, it came to light that LY293111 exhibited PPAR agonist activity in addition to its effects on the 5-lipoxygenase pathway. This raises the question of which of the two targets is of greatest importance with regard to the anticancer effects of this agent. The evidence to date is not conclusive, but suggests that the effects of LY293111 may be mediated by both LTB4 receptors and PPAR.

  16. Platelet alpha-2 adrenergic receptor-mediated phosphoinositide responses in endogenous depression

    International Nuclear Information System (INIS)

    Mori, Hideki; Koyama, Tsukasa; Yamashita, Itaru

    1991-01-01

    We have previously indicated that epinephrine stimulates phosphoinositide (PI) hydrolysis by activating alpha-2 adrenergic receptors in human platelets. This method involves the measurement of the accumulation of [ 3 H]-inositol-1-phosphate (IP-1) as an index of Pl hydrolysis; lithium is added to inhibit the metabolism of IP-1, thus giving an enhanced signal. In the present study, we assessed the platelet alpha-2 adrenergic receptor-mediated PI responses in samples from 15 unmedicated patients with endogenous depression and 15 age- and sex-matched control subjects. The responses to epinephrine in the depressed patients were significantly higher than those of the controls, whereas the basal values did not differ significantly. These results support the hypothesis that platelet alpha-2 adrenergic receptors may be supersensitive in patients with endogenous depression

  17. Bicarbonate Contributes to GABAA Receptor-Mediated Neuronal Excitation in Surgically-Resected Human Hypothalamic Hamartomas

    Science.gov (United States)

    Do-Young, Kim; Fenoglio, Kristina A.; Kerrigan, John F.; Rho, Jong M.

    2009-01-01

    SUMMARY The role of bicarbonate (HCO3-) in GABAA receptor-mediated depolarization of human hypothalamic hamartoma (HH) neurons was investigated using cellular electrophysiological and calcium imaging techniques. Activation of GABAA receptors with muscimol (30 μM) provoked neuronal excitation in over 70% of large (18-22 μM) HH neurons in HCO3- buffer. Subsequent perfusion of HCO3--free HEPES buffer produced partial suppression of muscimol-induced excitation. Additionally, 53% of large HH neurons under HCO3--free conditions exhibited reduced intracellular calcium accumulation by muscimol. These results suggest that HCO3- efflux through GABAA receptors on a subpopulation of large HH neurons may contribute to membrane depolarization and subsequent activation of L-type calcium channels. PMID:19022626

  18. Differences between lutropin-mediated and choriogonadotropin-mediated receptor activation.

    Science.gov (United States)

    Grzesik, Paul; Teichmann, Anke; Furkert, Jens; Rutz, Claudia; Wiesner, Burkhard; Kleinau, Gunnar; Schülein, Ralf; Gromoll, Jörg; Krause, Gerd

    2014-03-01

    The human lutropin/choriogonadotropin receptor (hLHR) for the gonadotropic hormones human luteinizing hormone (hLH; lutropin) and human choriogonadotropin (hCG) is crucial for normal sexual development and fertility. We aimed to unravel differences between the two hLHR hormones in molecular activation mechanisms at hLHR. We utilized a specific hLHR variant that lacks exon 10 (hLHR-delExon10), which maintains full cAMP signaling by hCG, but decreases hLH-induced receptor signaling, resulting in a pathogenic phenotype. Exon 10 encodes 27 amino acids within the hinge region, which is an extracellular segment that is important for signaling and hormone interaction. Initially, we assumed that the lack of exon 10 might disturb intermolecular trans-activation of hLH, a mechanism that has been reported for hCG at hLHR. Coexpression of signaling-deficient hLHR and binding-deficient hLHR can be used to examine the mechanisms of receptor signaling, in particular intermolecular cooperation and intramolecular cis-activation. Therefore, hLHR-delExon10 was combined with the hLHR Lys605→Glu mutant, in which signaling is abolished, and the hLHR mutant Cys131→Arg, in which binding is deficient. We found that hCG signaling was partially rescued, indicating trans-activation. However, the hLH signal could not be restored via forced trans-activation with any construct. Fluorescence cross-correlation spectroscopy detected oligomerization in all combinations, indicating that these functional differences cannot be explained by monomerization of hLHR-delExon10. Thus, our data demonstrate not only that the different behavior of hLH at hLHR-delExon10 is unlikely to be related to modified intermolecular receptor activation, but also that hLH may exclusively stimulate the targeted hLHR by cis-activation, whereas hCG is also capable of inducing trans-activation. © 2014 FEBS.

  19. Enhanced NMDA receptor-mediated intracellular calcium signaling in magnocellular neurosecretory neurons in heart failure rats.

    Science.gov (United States)

    Stern, Javier E; Potapenko, Evgeniy S

    2013-08-15

    An enhanced glutamate excitatory function within the hypothalamic supraoptic and paraventricluar nuclei is known to contribute to increased neurosecretory and presympathetic neuronal activity, and hence, neurohumoral activation, during heart failure (HF). Still, the precise mechanisms underlying enhanced glutamate-driven neuronal activity in HF remain to be elucidated. Here, we performed simultaneous electrophysiology and fast confocal Ca²⁺ imaging to determine whether altered N-methyl-d-aspartate (NMDA) receptor-mediated changes in intracellular Ca²⁺ levels (NMDA-ΔCa²⁺) occurred in hypothalamic magnocellular neurosecretory cells (MNCs) in HF rats. We found that activation of NMDA receptors resulted in a larger ΔCa²⁺ in MNCs from HF when compared with sham rats. The enhanced NMDA-ΔCa²⁺ was neither dependent on the magnitude of the NMDA-mediated current (voltage clamp) nor on the degree of membrane depolarization or firing activity evoked by NMDA (current clamp). Differently from NMDA receptor activation, firing activity evoked by direct membrane depolarization resulted in similar changes in intracellular Ca²⁺ in sham and HF rats. Taken together, our results support a relatively selective alteration of intracellular Ca²⁺ homeostasis and signaling following activation of NMDA receptors in MNCs during HF. The downstream functional consequences of such altered ΔCa²⁺ signaling during HF are discussed.

  20. Hormonally-mediated Epigenetic Changes to Steroid Receptors in the Developing Brain: Implications for Sexual Differentiation

    Science.gov (United States)

    Nugent, Bridget M.; Schwarz, Jaclyn M.; McCarthy, Margaret M.

    2010-01-01

    The establishment of sex-specific neural morphology, which underlies sex-specific behaviors, occurs during a perinatal sensitive window in which brief exposure to gonadal steroid hormones produces permanent masculinization of the brain. In the rodent, estradiol derived from testicular androgens is a principle organizational hormone. The mechanism by which transient estradiol exposure induces permanent differences in neuronal anatomy has been widely investigated, but remains elusive. Epigenetic changes, such as DNA methylation, allow environmental influences to alter long-term gene expression patterns and therefore may be a potential mediator of estradiol-induced organization of the neonatal brain. Here we review data that demonstrate sex and estradiol-induced differences in DNA methylation on the estrogen receptor α (ERα), estrogen receptor β (ERβ), and progesterone receptor (PR) promoters in sexually dimorphic brain regions across development. Contrary to the overarching view of DNA methylation as a permanent modification directly tied to gene expression, these data demonstrate that methylation patterns on steroid hormone receptors change across the life span and do not necessarily predict expression. Although further exploration into the mechanism and significance of estradiol-induced alterations in DNA methylation patterns in the neonatal brain is necessary, these results provide preliminary evidence that epigenetic alterations can occur in response to early hormone exposure and may mediate estradiol-induced organization of sex differences in the neonatal brain. PMID:20800064

  1. Role of the hinge region of glucocorticoid receptor for HEXIM1-mediated transcriptional repression

    International Nuclear Information System (INIS)

    Yoshikawa, Noritada; Shimizu, Noriaki; Sano, Motoaki; Ohnuma, Kei; Iwata, Satoshi; Hosono, Osamu; Fukuda, Keiichi; Morimoto, Chikao

    2008-01-01

    We previously reported that HEXIM1 (hexamethylene bisacetamide-inducible protein 1), which suppresses transcription elongation via sequestration of positive transcription elongation factor b (P-TEFb) using 7SK RNA as a scaffold, directly associates with glucocorticoid receptor (GR) to suppress glucocorticoid-inducible gene activation. Here, we revealed that the hinge region of GR is essential for its interaction with HEXIM1, and that oxosteroid receptors including GR show sequence homology in their hinge region and interact with HEXIM1, whereas the other members of nuclear receptors do not. We also showed that HEXIM1 suppresses GR-mediated transcription in two ways: sequestration of P-TEFb by HEXIM1 and direct interaction between GR and HEXIM1. In contrast, peroxisome proliferator-activated receptor γ-dependent gene expression is negatively modulated by HEXIM1 solely via sequestration of P-TEFb. We, therefore, conclude that HEXIM1 may act as a gene-selective transcriptional regulator via direct interaction with certain transcriptional regulators including GR and contribute to fine-tuning of, for example, glucocorticoid-mediated biological responses

  2. IL-6 Overexpression in ERG-Positive Prostate Cancer Is Mediated by Prostaglandin Receptor EP2.

    Science.gov (United States)

    Merz, Constanze; von Mässenhausen, Anne; Queisser, Angela; Vogel, Wenzel; Andrén, Ove; Kirfel, Jutta; Duensing, Stefan; Perner, Sven; Nowak, Michael

    2016-04-01

    Prostate cancer is the most diagnosed cancer in men and multiple risk factors and genetic alterations have been described. The TMPRSS2-ERG fusion event and the overexpression of the transcription factor ERG are present in approximately 50% of all prostate cancer patients, however, the clinical outcome is still controversial. Prostate tumors produce various soluble factors, including the pleiotropic cytokine IL-6, regulating cellular processes such as proliferation and metastatic segregation. Here, we used prostatectomy samples in a tissue microarray format and analyzed the co-expression and the clinicopathologic data of ERG and IL-6 using immunohistochemical double staining and correlated the read-out with clinicopathologic data. Expression of ERG and IL-6 correlated strongly in prostate tissue samples. Forced expression of ERG in prostate tumor cell lines resulted in significantly increased secretion of IL-6, whereas the down-regulation of ERG decreased IL-6 secretion. By dissecting the underlying mechanism in prostate tumor cell lines we show the ERG-mediated up-regulation of the prostanoid receptors EP2 and EP3. The prostanoid receptor EP2 was overexpressed in human prostate cancer tissue. Furthermore, the proliferation rate and IL-6 secretion in DU145 cells was reduced after treatment with EP2-receptor antagonist. Collectively, our study shows that the expression of ERG in prostate cancer is linked to the expression of IL-6 mediated by the prostanoid receptor EP2. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  3. Decreased α1-adrenergic receptor-mediated inositide hydrolysis in neurons from hypertensive rat brain

    International Nuclear Information System (INIS)

    Feldstein, J.B.; Gonzales, R.A.; Baker, S.P.; Sumners, C.; Crews, F.T.; Raizada, M.K.

    1986-01-01

    The expression of α 1 -adrenergic receptors and norepinephrine (NE)-stimulated hydrolysis of inositol phospholipid has been studied in neuronal cultures from the brains of normotensive (Wistar-Kyoto, WKY) and spontaneously hypertensive (SH) rats. Binding of 125 I-1-[β-(4-hydroxyphenyl)-ethyl-aminomethyl] tetralone (HEAT) to neuronal membranes was 68-85% specific and was rapid. Competition-inhibition experiments with various agonists and antagonists suggested that 125 I-HEAT bound selectively to α 1 -adrenergic receptors. Specific binding of 125 I-HEAT to neuronal membranes from SH rat brain cultures was 30-45% higher compared with binding in WKY normotensive controls. This increase was attributed to an increase in the number of α 1 -adrenergic receptors on SH rat brain neurons. Incubation of neuronal cultures of rat brain from both strains with NE resulted in a concentration-dependent stimulation of release of inositol phosphates, although neurons from SH rat brains were 40% less responsive compared with WKY controls. The decrease in responsiveness of SH rat brain neurons to NE, even though the α 1 -adrenergic receptors are increased, does not appear to be due to a general defect in membrane receptors and postreceptor signal transduction mechanisms. This is because neither the number of muscarinic-cholinergic receptors nor the carbachol-stimulated release of inositol phosphates is different in neuronal cultures from the brains of SH rats compared with neuronal cultures from the brains of WKY rats. These observations suggest that the increased expression of α 1 -adrenergic receptors does not parallel the receptor-mediated inositol phosphate hydrolysis in neuronal cultures from SH rat brain

  4. Histamine is a modulator of metamorphic competence in Strongylocentrotus purpuratus (Echinodermata: Echinoidea

    Directory of Open Access Journals (Sweden)

    Sutherby Josh

    2012-04-01

    Full Text Available Abstract Background A metamorphic life-history is present in the majority of animal phyla. This developmental mode is particularly prominent among marine invertebrates with a bentho-planktonic life cycle, where a pelagic larval form transforms into a benthic adult. Metamorphic competence (the stage at which a larva is capable to undergo the metamorphic transformation and settlement is an important adaptation both ecologically and physiologically. The competence period maintains the larval state until suitable settlement sites are encountered, at which point the larvae settle in response to settlement cues. The mechanistic basis for metamorphosis (the morphogenetic transition from a larva to a juvenile including settlement, i.e. the molecular and cellular processes underlying metamorphosis in marine invertebrate species, is poorly understood. Histamine (HA, a neurotransmitter used for various physiological and developmental functions among animals, has a critical role in sea urchin fertilization and in the induction of metamorphosis. Here we test the premise that HA functions as a developmental modulator of metamorphic competence in the sea urchin Strongylocentrotus purpuratus. Results Our results provide strong evidence that HA leads to the acquisition of metamorphic competence in S. purpuratus larvae. Pharmacological analysis of several HA receptor antagonists and an inhibitor of HA synthesis indicates a function of HA in metamorphic competence as well as programmed cell death (PCD during arm retraction. Furthermore we identified an extensive network of histaminergic neurons in pre-metamorphic and metamorphically competent larvae. Analysis of this network throughout larval development indicates that the maturation of specific neuronal clusters correlates with the acquisition of metamorphic competence. Moreover, histamine receptor antagonist treatment leads to the induction of caspase mediated apoptosis in competent larvae. Conclusions We

  5. The Influence of Receptor-Mediated Interactions on Reaction-Diffusion Mechanisms of Cellular Self-organisation

    KAUST Repository

    Klika, Vá clav; Baker, Ruth E.; Headon, Denis; Gaffney, Eamonn A.

    2011-01-01

    formation, motivating numerous theoretical and experimental studies, though its verification at the molecular level in biological systems has remained elusive. In this work, we consider the influence of receptor-mediated dynamics within the framework

  6. Determination of histamine in Iranian cheese using enzyme-linked ...

    African Journals Online (AJOL)

    john

    enzyme-linked immunosorbent assay (ELISA) method. Mojtaba ... Histamine is a simple chemical substance created during processing of the amine acid histidine. Histamine is also an .... Institute of environment Health and Forensic. Sciences ...

  7. Generation of a proton motive force by histidine decarboxylation and electrogenic histidine/histamine antiport in Lactobacillus buchneri.

    Science.gov (United States)

    Molenaar, D; Bosscher, J S; ten Brink, B; Driessen, A J; Konings, W N

    1993-05-01

    Lactobacillus buchneri ST2A vigorously decarboxylates histidine to the biogenic amine histamine, which is excreted into the medium. Cells grown in the presence of histidine generate both a transmembrane pH gradient, inside alkaline, and an electrical potential (delta psi), inside negative, upon addition of histidine. Studies of the mechanism of histidine uptake and histamine excretion in membrane vesicles and proteoliposomes devoid of cytosolic histidine decarboxylase activity demonstrate that histidine uptake, histamine efflux, and histidine/histamine exchange are electrogenic processes. Histidine/histamine exchange is much faster than the unidirectional fluxes of these substrates, is inhibited by an inside-negative delta psi and is stimulated by an inside positive delta psi. These data suggest that the generation of metabolic energy from histidine decarboxylation results from an electrogenic histidine/histamine exchange and indirect proton extrusion due to the combined action of the decarboxylase and carrier-mediated exchange. The abundance of amino acid decarboxylation reactions among bacteria suggests that this mechanism of metabolic energy generation and/or pH regulation is widespread.

  8. Serotonin(2) receptors mediate respiratory recovery after cervical spinal cord hemisection in adult rats.

    Science.gov (United States)

    Zhou, S Y; Basura, G J; Goshgarian, H G

    2001-12-01

    The aim of the present study was to specifically investigate the involvement of serotonin [5-hydroxytryptamine (5-HT(2))] receptors in 5-HT-mediated respiratory recovery after cervical hemisection. Experiments were conducted on C(2) spinal cord-hemisected, anesthetized (chloral hydrate, 400 mg/kg ip), vagotomized, pancuronium- paralyzed, and artificially ventilated female Sprague-Dawley rats in which CO(2) levels were monitored and maintained. Twenty-four hours after spinal hemisection, the ipsilateral phrenic nerve displayed no respiratory-related activity indicative of a functionally complete hemisection. Intravenous administration of the 5-HT(2A/2C)-receptor agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI) induced respiratory-related activity in the phrenic nerve ipsilateral to hemisection under conditions in which CO(2) was maintained at constant levels and augmented the activity induced under conditions of hypercapnia. The effects of DOI were found to be dose dependent, and the recovery of activity could be maintained for up to 2 h after a single injection. DOI-induced recovery was attenuated by the 5-HT(2)-receptor antagonist ketanserin but not with the 5-HT(2C)-receptor antagonist RS-102221, suggesting that 5-HT(2A) and not necessarily 5-HT(2C) receptors may be involved in the induction of respiratory recovery after cervical spinal cord injury.

  9. GABA(A) receptors mediate orexin-A induced stimulation of food intake.

    Science.gov (United States)

    Kokare, Dadasaheb M; Patole, Angad M; Carta, Anna; Chopde, Chandrabhan T; Subhedar, Nishikant K

    2006-01-01

    Although the role of orexins in sleep/wake cycle and feeding behavior is well established, underlying mechanisms have not been fully understood. An attempt has been made to investigate the role of GABA(A) receptors and their benzodiazepine site on the orexin-A induced response to feeding. Different groups of rats were food deprived overnight and next day injected intracerebroventricularly (icv) with vehicle (artificial CSF; 5 microl/rat) or orexin-A (20-50 nM/rat) and the animals were given free access to food. Cumulative food intake was measured during light phase of light/dark cycle at 1-, 2-, 4- and 6-h post-injection time points. Orexin-A (30-50 nM/rat, icv) stimulated food intake at all the time points (P GABA(A) receptor agonists muscimol (25 ng/rat, icv) and diazepam (0.5 mg/kg, ip) at subeffective doses significantly potentiated the hyperphagic effect of orexin-A (30 nM/rat, icv). However, the effect was negated by the GABA(A) receptor antagonist bicuculline (1 mg/kg, ip). Interestingly, benzodiazepine receptor antagonist flumazenil (5 ng/rat, icv), augmented the orexin-A (30 nM/rat, icv) induced hyperphagia; the effect may be attributed to the intrinsic activity of the agent. The results suggest that the hyperphagic effect of orexin-A, at least in part, is mediated by enhanced GABA(A) receptor activity.

  10. Receptor-mediated internalization of [3H]-neurotensin in synaptosomal preparations from rat neostriatum.

    Science.gov (United States)

    Nguyen, Ha Minh Ky; Cahill, Catherine M; McPherson, Peter S; Beaudet, Alain

    2002-06-01

    Following its binding to somatodendritic receptors, the neuropeptide neurotensin (NT) internalizes via a clathrin-mediated process. In the present study, we investigated whether NT also internalizes presynaptically using synaptosomes from rat neostriatum, a region in which NT1 receptors are virtually all presynaptic. Binding of [(3)H]-NT to striatal synaptosomes in the presence of levocabastine to block NT2 receptors is specific, saturable, and has NT1 binding properties. A significant fraction of the bound radioactivity is resistant to hypertonic acid wash indicating that it is internalized. Internalization of [(3)H]-NT, like that of [(125)I]-transferrin, is blocked by sucrose and low temperature, consistent with endocytosis occurring via a clathrin-dependent pathway. However, contrary to what was reported at the somatodendritic level, neither [(3)H]-NT nor [(125)I]-transferrin internalization in synaptosomes is sensitive to the endocytosis inhibitor phenylarsine oxide. Moreover, treatment of synaptosomes with monensin, which prevents internalized receptors from recycling to the plasma membrane, reduces [(3)H]-NT binding and internalization, suggesting that presynaptic NT1 receptors, in contrast to somatodendritic ones, are recycled back to the plasma membrane. Taken together, these results suggest that NT internalizes in nerve terminals via an endocytic pathway that is related to, but is mechanistically distinct from that responsible for NT internalization in nerve cell bodies.

  11. Histamine intolerance as a cause of chronic digestive complaints in pediatric patients

    Directory of Open Access Journals (Sweden)

    Antonio Rosell-Camps

    2013-04-01

    Full Text Available Introduction: histamine intolerance (HI is a poorly described disease in gastroenterology that may present with predominant digestive complaints. The goals of this study include a report of two cases diagnosed in a pediatric gastroenterology clinic. Material and methods: observational, retrospective study of patients diagnosed with HI from September 2010 to December 2011 at the pediatric gastroenterology clinic of a tertiary hospital. They were deemed to have a diagnosis of HI in the presence of 2 or more characteristic digestive complaints, decreased diamino oxidase (DAO levels and/or response to a low histamine diet with negative IgE-mediated food allergy tests. Results: sixteen patients were diagnosed. Males predominated versus females (11/5. Mean age at symptom onset was 4 years (6 months vs. 13 years and 6 months and mean age at diagnosis was 6 years and 6 months (17 months vs. 13 years and 11 months, with an interval of 2 years and 1 month between symptom onset and diagnosis (5 months vs. 4 years. Predominant symptoms included diffuse abdominal pain (16/16, intermittent diarrhea (10/16, headache (5/16, intermittent vomiting (4/16, and skin rash (2/16. The diagnosis was established by measuring plasma diamino oxidase levels, which were below 10 kU/L (normal > 10 kU/L in 14 cases, and symptom clearance on initiating a low histamine diet. In two patients DAO levels were above 10 kU/L but responded to diet. Treatment was based on a diet low in histamine-contaning food, and antihistamines H1 y H2 had to be added for two cases. Conclusions: histamine intolerance is a little known disease with a potentially relevant incidence. Predominant complaints include diffuse abdominal pain, diarrhea, headache, and chronic intermittent vomiting. Its diagnosis is based on clinical suspicion, plasma DAO measurement, and response to a low histamine diet. Management with the latter provides immediate improvement.

  12. Cowhage-induced itch as an experimental model for pruritus. A comparative study with histamine-induced itch.

    Directory of Open Access Journals (Sweden)

    Alexandru D P Papoiu

    2011-03-01

    Full Text Available Histamine is the prototypical pruritogen used in experimental itch induction. However, in most chronic pruritic diseases, itch is not predominantly mediated by histamine. Cowhage-induced itch, on the other hand, seems more characteristic of itch occurring in chronic pruritic diseases.We tested the validity of cowhage as an itch-inducing agent by contrasting it with the classical itch inducer, histamine, in healthy subjects and atopic dermatitis (AD patients. We also investigated whether there was a cumulative effect when both agents were combined.Fifteen healthy individuals and fifteen AD patients were recruited. Experimental itch induction was performed in eczema-free areas on the volar aspects of the forearm, using different itch inducers: histamine, cowhage and their combination thereof. Itch intensity was assessed continuously for 5.5 minutes after stimulus application using a computer-assisted visual analogue scale (COVAS.In both healthy and AD subjects, the mean and peak intensity of itch were higher after the application of cowhage compared to histamine, and were higher after the combined application of cowhage and histamine, compared to histamine alone (p<0.0001 in all cases. Itch intensity ratings were not significantly different between healthy and AD subjects for the same itch inducer used; however AD subjects exhibited a prolonged itch response in comparison to healthy subjects (p<0.001.Cowhage induced a more intense itch sensation compared to histamine. Cowhage was the dominant factor in itch perception when both pathways were stimulated in the same time. Cowhage-induced itch is a suitable model for the study of itch in AD and other chronic pruritic diseases, and it can serve as a new model for testing antipruritic drugs in humans.

  13. Different AMPA receptor subtypes mediate the distinct kinetic components of a biphasic EPSC in hippocampal interneurons

    Directory of Open Access Journals (Sweden)

    Todd eStincic

    2015-05-01

    Full Text Available CA1 hippocampal interneurons at the border between stratum radiatum and stratum lacunosum-moleculare have AMPA receptor (AMPAR-mediated excitatory postsynaptic currents (EPSCs that consist of two distinct phases: a typical fast component (FC, and a highly unusual slow component (SC that persists for hundreds of milliseconds. To determine whether these kinetically distinct components of the EPSC are mediated by distinct AMPAR subpopulations, we examined the relative contributions of GluA2-containing and –lacking AMPARs to the SC. GluA2-containing AMPARs mediated the majority of the FC whereas GluA2-lacking AMPARs preferentially generated the SC. When glutamate uptake through the glial glutamate transporter EAAT1 was inhibited, spill over-mediated AMPAR activation recruited an even slower third kinetic component that persisted for several seconds; however, this spillover-mediated current was mediated predominantly by GluA2-containing AMPARs and therefore was clearly distinct from the SC when uptake is intact. Thus, different AMPAR subpopulations that vary in GluA2 content mediate the distinct components of the AMPAR EPSC. The SC is developmentally downregulated in mice, declining after the second postnatal week. This downregulation affects both GluA2-containing and GluA2-lacking AMPARs mediating the SC, and is not accompanied by developmental changes in the GluA2 content of AMPARs underlying the FC. Thus, the downregulation of the SC appears to be independent of synaptic GluA2 expression, suggesting the involvement of another AMPAR subunit or an auxiliary protein. Our results therefore identify GluA2-dependent and GluA2-independent determinants of the SC: GluA2-lacking AMPARs preferentially contribute to the SC, while the developmental downregulation of the SC is independent of GluA2 content.

  14. The brain cytoplasmic RNA BC1 regulates dopamine D-2 receptor-mediated transmission in the striatum

    OpenAIRE

    Centonze, Diego; Rossi, Silvia; Napoli, Ilaria; Mercaldo, Valentina; Lacoux, Caroline; Ferrari, Francesca; Ciotti, Maria Teresa; De Chiara, Valentina; Prosperetti, Chiara; Maccarrone, Mauro; Fezza, Filomena; Calabresi, Paolo; Bernardi, Giorgio; Bagni, Claudia

    2007-01-01

    Dopamine D-2 receptor (D2DR)-mediated transmission in the striatum is remarkably flexible, and changes in its efficacy have been heavily implicated in a variety of physiological and pathological conditions. Although receptor-associated proteins are clearly involved in specific forms of synaptic plasticity, the molecular mechanisms regulating the sensitivity of D-2 receptors in this brain area are essentially obscure. We have studied the physiological responses of the D2DR stimulations in mice...

  15. Muscarinic receptors mediate cold stress-induced detrusor overactivity in type 2 diabetes mellitus rats.

    Science.gov (United States)

    Imamura, Tetsuya; Ishizuka, Osamu; Ogawa, Teruyuki; Yamagishi, Takahiro; Yokoyama, Hitoshi; Minagawa, Tomonori; Nakazawa, Masaki; Gautam, Sudha Silwal; Nishizawa, Osamu

    2014-10-01

    This study determined if muscarinic receptors could mediate the cold stress-induced detrusor overactivity induced in type 2 diabetes mellitus rats. Ten-week-old female Goto-Kakizaki diabetic rats (n = 12) and Wister Kyoto non-diabetic rats (n = 12) were maintained on a high-fat diet for 4 weeks. Cystometric investigations of the unanesthetized rats were carried out at room temperature (27 ± 2°C) for 20 min. They were intravenously administered imidafenacin (0.3 mg/kg, n = 6) or vehicle (n = 6). After 5 min, the rats were transferred to a low temperature (4 ± 2°C) for 40 min where the cystometry was continued. The rats were then returned to room temperature for the final cystometric measurements. Afterwards, expressions of bladder muscarinic receptor M3 and M2 messenger ribonucleic acids and proteins were assessed by reverse transcription polymerase chain reaction and immunohistochemistry. In non-diabetic Wister Kyoto rats, imidafenacin did not reduce cold stress-induced detrusor overactivity. In diabetic Goto-Kakizaki rats, just after transfer to a low temperature, the cold stress-induced detrusor overactivity in imidafenacin-treated rats was reduced compared with vehicle-treated rats. Within the urinary bladders, the ratio of M3 to M2 receptor messenger ribonucleic acid in the diabetic Goto-Kakizaki rats was significantly higher than that of the non-diabetic Wister Kyoto rats. The proportion of muscarinic M3 receptor-positive area within the detrusor in diabetic Goto-Kakizaki rats was also significantly higher than that in non-diabetic Wister Kyoto rats. Imidafenacin partially inhibits cold stress-induced detrusor overactivity in diabetic Goto-Kakizaki rats. In this animal model, muscarinic M3 receptors partially mediate cold stress-induced detrusor overactivity. © 2014 The Japanese Urological Association.

  16. Characterization of GABA/sub A/ receptor-mediated 36chloride uptake in rat brain synaptoneurosomes

    International Nuclear Information System (INIS)

    Luu, M.D.; Morrow, A.L.; Paul, S.M.; Schwartz, R.D.

    1987-01-01

    γ-Aminobutyric acid (GABA) receptor-mediated 36 chloride ( 36 Cl - ) uptake was measured in synaptoneurosomes from rat brain. GABA and GABA agonists stimulated 36 Cl - uptake in a concentration-dependent manner with the following order of potency: Muscimol>GABA>piperidine-4-sulfonic acid (P4S)>4,5,6,7-tetrahydroisoxazolo-[5,4-c]pyridin-3-ol (THIP)=3-aminopropanesulfonic acid (3APS)>>taurine. Both P4S and 3APS behaved as partial agonists, while the GABA/sub B/ agonist, baclofen, was ineffective. The response to muscimol was inhibited by bicuculline and picrotoxin in a mixed competitive/non-competitive manner. Other inhibitors of GABA receptor-opened channels or non-neuronal anion channels such as penicillin, picrate, furosemide and disulfonic acid stilbenes also inhibited the response to muscimol. A regional variation in muscimol-stimulated 36 Cl - uptake was observed; the largest responses were observed in the cerebral cortex, cerebellum and hippocampus, moderate responses were obtained in the striatum and hypothalamus and the smallest response was observed in the pons-medulla. GABA receptor-mediated 36 Cl - uptake was also dependent on the anion present in the media. The muscinol response varied in media containing the following anions: Br - >Cl - ≥NO 3 - >I - ≥SCN - >>C 3 H 5 OO - ≥ClO 4 - >F - , consistent with the relative anion permeability through GABA receptor-gated anion channels and the enhancement of convulsant binding to the GABA receptor-gated Cl - channel. 43 references, 4 figures, 3 tables

  17. 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...

  18. Glutamate Receptors within the Mesolimbic Dopamine System Mediate Alcohol Relapse Behavior.

    Science.gov (United States)

    Eisenhardt, Manuela; Leixner, Sarah; Luján, Rafael; Spanagel, Rainer; Bilbao, Ainhoa

    2015-11-25

    Glutamatergic input within the mesolimbic dopamine (DA) pathway plays a critical role in the development of addictive behavior. Although this is well established for some drugs of abuse, it is not known whether glutamate receptors within the mesolimbic system are involved in mediating the addictive properties of chronic alcohol use. Here we evaluated the contribution of mesolimbic NMDARs and AMPARs in mediating alcohol-seeking responses induced by environmental stimuli and relapse behavior using four inducible mutant mouse lines lacking the glutamate receptor genes Grin1 or Gria1 in either DA transporter (DAT) or D1R-expressing neurons. We first demonstrate the lack of GluN1 or GluA1 in either DAT- or D1R-expressing neurons in our mutant mouse lines by colocalization studies. We then show that GluN1 and GluA1 receptor subunits within these neuronal subpopulations mediate the alcohol deprivation effect, while having no impact on context- plus cue-induced reinstatement of alcohol-seeking behavior. We further validated these results pharmacologically by demonstrating similar reductions in the alcohol deprivation effect after infusion of the NMDAR antagonist memantine into the nucleus accumbens and ventral tegmental area of control mice, and a rescue of the mutant phenotype via pharmacological potentiation of AMPAR activity using aniracetam. In conclusion, dopamine neurons as well as D1R-expressing medium spiny neurons and their glutamatergic inputs via NMDARs and AMPARs act in concert to influence relapse responses. These results provide a neuroanatomical and molecular substrate for relapse behavior and emphasize the importance of glutamatergic drugs in modulating relapse behavior. Here we provide genetic and pharmacological evidence that glutamate receptors within the mesolimbic dopamine system play an essential role in alcohol relapse. Using various inducible and site-specific transgenic mouse models and pharmacological validation experiments, we show that critical

  19. Purinergic receptor antagonists inhibit odorant-mediated CREB phosphorylation in sustentacular cells of mouse olfactory epithelium.

    LENUS (Irish Health Repository)

    Dooley, Ruth

    2012-02-01

    BACKGROUND: Extracellular nucleotides have long been known to play neuromodulatory roles and to be involved in intercellular signalling. In the olfactory system, ATP is released by olfactory neurons, and exogenous ATP can evoke an increase in intracellular calcium concentration in sustentacular cells, the nonneuronal supporting cells of the olfactory epithelium. Here we investigate the hypothesis that olfactory neurons communicate with sustentacular cells via extracellular ATP and purinergic receptor activation. RESULTS: Here we show that exposure of mice to a mixture of odorants induced a significant increase in the levels of the transcription factor CREB phosphorylated at Ser-133 in the nuclei of both olfactory sensory neurons and sustentacular cells. This activation was dependent on adenylyl cyclase III-mediated olfactory signaling and on activation of P2Y purinergic receptors on sustentacular cells. Purinergic receptor antagonists inhibited odorant-dependent CREB phosphorylation specifically in the nuclei of the sustentacular cells. CONCLUSION: Our results point to a possible role for extracellular nucleotides in mediating intercellular communication between the neurons and sustentacular cells of the olfactory epithelium in response to odorant exposure. Maintenance of extracellular ionic gradients and metabolism of noxious chemicals by sustentacular cells may therefore be regulated in an odorant-dependent manner by olfactory sensory neurons.

  20. Purinergic receptor antagonists inhibit odorant-mediated CREB phosphorylation in sustentacular cells of mouse olfactory epithelium

    LENUS (Irish Health Repository)

    Dooley, Ruth

    2011-08-22

    Abstract Background Extracellular nucleotides have long been known to play neuromodulatory roles and to be involved in intercellular signalling. In the olfactory system, ATP is released by olfactory neurons, and exogenous ATP can evoke an increase in intracellular calcium concentration in sustentacular cells, the nonneuronal supporting cells of the olfactory epithelium. Here we investigate the hypothesis that olfactory neurons communicate with sustentacular cells via extracellular ATP and purinergic receptor activation. Results Here we show that exposure of mice to a mixture of odorants induced a significant increase in the levels of the transcription factor CREB phosphorylated at Ser-133 in the nuclei of both olfactory sensory neurons and sustentacular cells. This activation was dependent on adenylyl cyclase III-mediated olfactory signaling and on activation of P2Y purinergic receptors on sustentacular cells. Purinergic receptor antagonists inhibited odorant-dependent CREB phosphorylation specifically in the nuclei of the sustentacular cells. Conclusion Our results point to a possible role for extracellular nucleotides in mediating intercellular communication between the neurons and sustentacular cells of the olfactory epithelium in response to odorant exposure. Maintenance of extracellular ionic gradients and metabolism of noxious chemicals by sustentacular cells may therefore be regulated in an odorant-dependent manner by olfactory sensory neurons.

  1. SR-B1 Is a Silica Receptor that Mediates Canonical Inflammasome Activation

    Directory of Open Access Journals (Sweden)

    Misato Tsugita

    2017-01-01

    Full Text Available The inhalation of silica dust is associated with fibrosis and lung cancer, which are triggered by macrophage inflammatory responses; however, how macrophages recognize silica remains largely unknown. Here, we identify by functional expression cloning the class B scavenger receptor SR-B1 as a silica receptor. Through an extracellular α-helix, both mouse and human SR-B1 specifically recognized amorphous and crystalline silica, but not titanium dioxide nanoparticles, latex nanoparticles, or monosodium urate crystals, although all particles exhibited negative surface potentials. Genetic deletion of SR-B1 and masking of SR-B1 by monoclonal antibodies showed that SR-B1-mediated recognition of silica is associated with caspase-1-mediated inflammatory responses in mouse macrophages and human peripheral blood monocytes. Furthermore, SR-B1 was involved in silica-induced pulmonary inflammation in mice. These results indicate that SR-B1 is a silica receptor associated with canonical inflammasome activation.

  2. Stimulatory Effects of Melatonin on Porcine In Vitro Maturation Are Mediated by MT2 Receptor

    Directory of Open Access Journals (Sweden)

    Sanghoon Lee

    2018-05-01

    Full Text Available Melatonin is a multifunctional molecule with numerous biological activities. The fact that melatonin modulates the functions of porcine granulosa cells via the MT2 receptor suggests the possibility of MT2 receptor-mediation for melatonin to promote cumulus expansion of porcine cumulus-oocyte complexes (COCs. Therefore, we investigated the presence of MT2 in porcine COCs, and the effects of melatonin with or without selective MT2 antagonists (luzindole and 4-P-PDOT on this process; COCs underwent in vitro maturation culturing with six different conditions (control, melatonin, luzindole, 4-P-PDOT, melatonin + luzindole or melatonin + 4-P-PDOT. Cumulus expansion, oocyte nuclear maturation, and subsequent embryo development after parthenogenetic activation (PA were evaluated. In experiment 1, MT2 was expressed in both oocytes and cumulus cells. In experiment 2, melatonin significantly increased the proportion of complete cumulus expansion (degree 4, which was inhibited by simultaneous addition of either luzindole or 4-P-PDOT. A similar pattern was observed in the expression of genes related to cumulus expansion, apoptosis, and MT2. In experiment 3, no significant difference was observed in immature, degenerate, and MII oocyte rates among the groups. In experiment 4, melatonin significantly increased blastocyst formation rates and total blastocyst cell numbers after PA, but these effects were abolished when either luzindole or 4-P-PDOT was added concomitantly. In conclusion, our results indicate that the MT2 receptor mediated the stimulatory effects of melatonin on porcine cumulus expansion and subsequent embryo development.

  3. Mannose Receptor Mediates the Immune Response to Ganoderma atrum Polysaccharides in Macrophages.

    Science.gov (United States)

    Li, Wen-Juan; Tang, Xiao-Fang; Shuai, Xiao-Xue; Jiang, Cheng-Jia; Liu, Xiang; Wang, Le-Feng; Yao, Yu-Fei; Nie, Shao-Ping; Xie, Ming-Yong

    2017-01-18

    The ability of mannose receptor (MR) to recognize the carbohydrate structures is well-established. Here, we reported that MR was crucial for the immune response to a Ganoderma atrum polysaccharide (PSG-1), as evidenced by elevation of MR in association with increase of phagocytosis and concentrations of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in normal macrophages. Elevation of MR triggered by PSG-1 also led to control lipopolysaccharide (LPS)-triggered inflammatory response via the increase of interleukin-10 (IL-10) and inhibition of phagocytosis and IL-1β. Anti-MR antibody partly attenuated PSG-1-mediated anti-inflammatory responses, while it could not affect TNF-α secretion, suggesting that another receptor was involved in PSG-1-triggered immunomodulatory effects. MR and toll-like receptor (TLR)4 coordinated the influences on the TLR4-mediated signaling cascade by the nuclear factor-κB (NF-κB) pathway in LPS-stimulated macrophages subjected to PSG-1. Collectively, immune response to PSG-1 required recognition by MR in macrophages. The NF-κB pathway served as a central role for the coordination of MR and TLR4 to elicit immune response to PSG-1.

  4. Purinergic receptor antagonists inhibit odorant-mediated CREB phosphorylation in sustentacular cells of mouse olfactory epithelium

    Directory of Open Access Journals (Sweden)

    Hatt Hanns

    2011-08-01

    Full Text Available Abstract Background Extracellular nucleotides have long been known to play neuromodulatory roles and to be involved in intercellular signalling. In the olfactory system, ATP is released by olfactory neurons, and exogenous ATP can evoke an increase in intracellular calcium concentration in sustentacular cells, the nonneuronal supporting cells of the olfactory epithelium. Here we investigate the hypothesis that olfactory neurons communicate with sustentacular cells via extracellular ATP and purinergic receptor activation. Results Here we show that exposure of mice to a mixture of odorants induced a significant increase in the levels of the transcription factor CREB phosphorylated at Ser-133 in the nuclei of both olfactory sensory neurons and sustentacular cells. This activation was dependent on adenylyl cyclase III-mediated olfactory signaling and on activation of P2Y purinergic receptors on sustentacular cells. Purinergic receptor antagonists inhibited odorant-dependent CREB phosphorylation specifically in the nuclei of the sustentacular cells. Conclusion Our results point to a possible role for extracellular nucleotides in mediating intercellular communication between the neurons and sustentacular cells of the olfactory epithelium in response to odorant exposure. Maintenance of extracellular ionic gradients and metabolism of noxious chemicals by sustentacular cells may therefore be regulated in an odorant-dependent manner by olfactory sensory neurons.

  5. Identification of potential pathway mediation targets in Toll-like receptor signaling.

    Directory of Open Access Journals (Sweden)

    Fan Li

    2009-02-01

    Full Text Available Recent advances in reconstruction and analytical methods for signaling networks have spurred the development of large-scale models that incorporate fully functional and biologically relevant features. An extended reconstruction of the human Toll-like receptor signaling network is presented herein. This reconstruction contains an extensive complement of kinases, phosphatases, and other associated proteins that mediate the signaling cascade along with a delineation of their associated chemical reactions. A computational framework based on the methods of large-scale convex analysis was developed and applied to this network to characterize input-output relationships. The input-output relationships enabled significant modularization of the network into ten pathways. The analysis identified potential candidates for inhibitory mediation of TLR signaling with respect to their specificity and potency. Subsequently, we were able to identify eight novel inhibition targets through constraint-based modeling methods. The results of this study are expected to yield meaningful avenues for further research in the task of mediating the Toll-like receptor signaling network and its effects.

  6. Killing of intracellular Mycobacterium tuberculosis by receptor-mediated drug delivery

    International Nuclear Information System (INIS)

    Majumdar, S.; Basu, S.K.

    1991-01-01

    p-Aminosalicylic acid (PAS) conjugated to maleylated bovine serum albumin (MBSA) was taken up efficiently through high-affinity MBSA-binding sites on macrophages. Binding of the radiolabeled conjugate to cultured mouse peritoneal macrophages at 4 degrees C was competed for by MBSA but not by PAS. At 37 degrees C, the radiolabeled conjugate was rapidly degraded by the macrophages, leading to release of acid-soluble degradation products in the medium. The drug conjugate was nearly 100 times as effective as free PAS in killing the intracellular mycobacteria in mouse peritoneal macrophages infected in culture with Mycobacterium tuberculosis. The killing of intracellular mycobacteria mediated by the drug conjugate was effectively prevented by simultaneous addition of excess MBSA (100 micrograms/ml) or chloroquine (3 microM) to the medium, whereas these agents did not affect the microbicidal action of free PAS. These results suggest that (i) uptake of the PAS-MBSA conjugate was mediated by cell surface receptors on macrophages which recognize MBSA and (ii) lysosomal hydrolysis of the internalized conjugate resulted in intracellular release of a pharmacologically active form of the drug, which led to selective killing of the M. tuberculosis harbored by mouse macrophages infected in culture. This receptor-mediated modality of delivering drugs to macrophages could contribute to greater therapeutic efficacy and minimization of toxic side effects in the management of tuberculosis and other intracellular mycobacterial infections

  7. NMDA receptors mediate neuron-to-glia signaling in mouse cortical astrocytes.

    Science.gov (United States)

    Lalo, Ulyana; Pankratov, Yuri; Kirchhoff, Frank; North, R Alan; Verkhratsky, Alexei

    2006-03-08

    Chemical transmission between neurons and glial cells is an important element of integration in the CNS. Here, we describe currents activated by NMDA in cortical astrocytes, identified in transgenic mice that express enhanced green fluorescent protein under control of the human glial fibrillary acidic protein promoter. Astrocytes were studied by whole-cell voltage clamp either in slices or after gentle nonenzymatic mechanical dissociation. Acutely isolated astrocytes showed a three-component response to glutamate. The initial rapid component was blocked by 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide (NBQX), which is an antagonist of AMPA receptors (IC50, 2 microM), and the NMDA receptor antagonist D-AP-5 blocked the later sustained component (IC50, 0.6 microM). The third component of glutamate application response was sensitive to D,L-threo-beta-benzyloxyaspartate, a glutamate transporter blocker. Fast application of NMDA evoked concentration-dependent inward currents (EC50, 0.3 microM); these showed use-dependent block by (+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine maleate (MK-801). These NMDA-evoked currents were linearly dependent on membrane potential and were not affected by extracellular magnesium at concentrations up to 10 mM. Electrical stimulation of axons in layer IV-VI induced a complex inward current in astrocytes situated in the cortical layer II, part of which was sensitive to MK-801 at holding potential -80 mV and was not affected by the AMPA glutamate receptor antagonist NBQX. The fast miniature spontaneous currents were observed in cortical astrocytes in slices as well. These currents exhibited both AMPA and NMDA receptor-mediated components. We conclude that cortical astrocytes express functional NMDA receptors that are devoid of Mg2+ block, and these receptors are involved in neuronal-glial signal transmission.

  8. Targeting of liposomes to cells bearing nerve growth factor receptors mediated by biotinylated NGF

    International Nuclear Information System (INIS)

    Rosenberg, M.B.

    1986-01-01

    Previous studies of liposome targeting have concentrated on immunological systems, the use of ligand-receptor interactions has received little attention. The protein hormone beta-nerve growth factor (NGF) was modified by biotinylation via carboxyl group substitution (C-bio-NGF) under reaction conditions that yielded an average of 3 biotin additions per NGF subunit. NGF was also biotinylated through amino group substitution to produce derivatives with ratios of 1, 2 and 4 biotin moieties per NGF subunit (N-bio-NGF). These derivatives were compared with native NGF for their ability to compete with 125 I-NGF for binding to NGF receptors on rat pheochromocytoma (PC 12) cells at 4 0 C. C-bio-NGF was as effective as native NGF in binding to NGF receptors, while N-bio-NGF containing 1 biotin per NGF subunit was only 28% as active in binding as native NGF. C-bio-NGF, but not N-bio-NGF, mediated the specific binding of 125 I-streptavidin to PC12 cells. Biocytin-NGF, a derivative of C-bio-NGF with an extended spacer chain, was also synthesized and retained full biological and receptor binding activities. C-bio-NGF and biocytin-NGF were as effective as native NGF in a bioassay involving induction of neurite outgrowth from PC12 cells

  9. Electroacupuncture Potentiates Cannabinoid Receptor-Mediated Descending Inhibitory Control in a Mouse Model of Knee Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Xiao-Cui Yuan

    2018-04-01

    Full Text Available Knee osteoarthritis (KOA is a highly prevalent, chronic joint disorder, which can lead to chronic pain. Although electroacupuncture (EA is effective in relieving chronic pain in the clinic, the involved mechanisms remain unclear. Reduced diffuse noxius inhibitory controls (DNIC function is associated with chronic pain and may be related to the action of endocannabinoids. In the present study, we determined whether EA may potentiate cannabinoid receptor-mediated descending inhibitory control and inhibit chronic pain in a mouse model of KOA. We found that the optimized parameters of EA inhibiting chronic pain were the low frequency and high intensity (2 Hz + 1 mA. EA reversed the reduced expression of CB1 receptors and the 2-arachidonoylglycerol (2-AG level in the midbrain in chronic pain. Microinjection of the CB1 receptor antagonist AM251 into the ventrolateral periaqueductal gray (vlPAG can reversed the EA effect on pain hypersensitivity and DNIC function. In addition, CB1 receptors on GABAergic but not glutamatergic neurons are involved in the EA effect on DNIC function and descending inhibitory control of 5-HT in the medulla, thus inhibiting chronic pain. Our data suggest that endocannabinoid (2-AG-CB1R-GABA-5-HT may be a novel signaling pathway involved in the effect of EA improving DNIC function and inhibiting chronic pain.

  10. Evidence that 5-hydroxytryptamine/sub 3/ receptors mediate cytotoxic drug and radiation-evoked emesis

    Energy Technology Data Exchange (ETDEWEB)

    Miner, W.D.; Sanger, G.J.; Turner, D.H.

    1987-08-01

    The involvement of 5-hydroxytryptamine (5-HT) 5-HT/sub 3/ receptors in the mechanisms of severe emesis evoked by cytotoxic drugs or by total body irradiation have been studied in ferrets. Anti-emetic compounds tested were domperidone (a dopamine antagonist), metoclopramide (a gastric motility stimulant and dopamine antagonist at conventional doses, a 5-HT/sub 3/ receptor antagonist at higher doses) and BRL 24924 (a potent gastric motility stimulant and a 5-HT/sub 3/ receptor antagonist). Domperidone or metoclopramide prevented apomorphine-evoked emesis, whereas BRL 24924 did not. Similar doses of domperidone did not prevent emesis evoked by cis-platin or by total body irradiation, whereas metoclopramide or BRL 24924 greatly reduced or prevented these types of emesis. Metoclopramide and BRL 24924 also prevented emesis evoked by a combination of doxorubicin and cyclophosphamide. These results are discussed in terms of a fundamental role for 5-HT/sub 3/ receptors in the mechanisms mediating severely emetogenic cancer treatment therapies.

  11. Beta receptor-mediated modulation of the late positive potential in humans.

    Science.gov (United States)

    de Rover, Mischa; Brown, Stephen B R E; Boot, Nathalie; Hajcak, Greg; van Noorden, Martijn S; van der Wee, Nic J A; Nieuwenhuis, Sander

    2012-02-01

    Electrophysiological studies have identified a scalp potential, the late positive potential (LPP), which is modulated by the emotional intensity of observed stimuli. Previous work has shown that the LPP reflects the modulation of activity in extrastriate visual cortical structures, but little is known about the source of that modulation. The present study investigated whether beta-adrenergic receptors are involved in the generation of the LPP. We used a genetic individual differences approach (experiment 1) and a pharmacological manipulation (experiment 2) to test the hypothesis that the LPP is modulated by the activation of β-adrenergic receptors. In experiment 1, we found that LPP amplitude depends on allelic variation in the β1-receptor gene polymorphism. In experiment 2, we found that LPP amplitude was modulated by the β-blocker propranolol in a direction dependent on subjects' level of trait anxiety: In participants with lower trait anxiety, propranolol led to a (nonsignificant) decrease in the LPP modulation; in participants with higher trait anxiety, propranolol increased the emotion-related LPP modulation. These results provide initial support for the hypothesis that the LPP reflects the downstream effects, in visual cortical areas, of β-receptor-mediated activation of the amygdala.

  12. The effect of vanadate on receptor-mediated endocytosis of asialoorosomucoid in rat liver parenchymal cells

    International Nuclear Information System (INIS)

    Kindberg, G.M.; Gudmundsen, O.; Berg, T.

    1990-01-01

    Vanadate is a phosphate analogue that inhibits enzymes involved in phosphate release and transfer reactions. Since such reactions may play important roles in endocytosis, we studied the effects of vanadate on various steps in receptor-mediated endocytosis of asialoorosomucoid labeled with 125I-tyramine-cellobiose (125I-TC-AOM). The labeled degradation products formed from 125I-TC-AOM are trapped in the lysosomes and may therefore serve as lysosomal markers in subcellular fractionation studies. Vanadate reduced the amount of active surface asialoglycoprotein receptors approximately 70%, but had no effect on the rate of internalization and retroendocytosis of ligand. The amount of surface asialoglycoprotein receptors can be reduced by lowering the incubation temperature gradually from 37 to 15 degrees C; vanadate affected only the temperature--sensitive receptors. Vanadate inhibited degradation of 125I-TC-AOM 70-80%. Degradation was much more sensitive to vanadate than binding; half-maximal effects were seen at approximately 1 mM vanadate for binding and approximately 0.1 mM vanadate for degradation. By subcellular fractionation in sucrose and Nycodenz gradients, it was shown that vanadate completely prevented the transfer of 125I-TC-AOM from endosomes to lysosomes. Therefore, the inhibition of degradation by vanadate was indirect; in the presence of vanadate, ligand did not gain access to the lysosomes. The limited degradation in the presence of vanadate took place in a prelysosomal compartment. Vanadate did not affect cell viability and ATP content

  13. Receptor-mediated photo-cytotoxicity: synthesis of a photoactivatable psoralen derivative conjugated to insulin.

    Science.gov (United States)

    Gasparro, F P; Knobler, R M; Yemul, S S; Bisaccia, E; Edelson, R L

    1986-12-15

    4'-Aminomethyl-4,5',8-trimethylpsoralen has been chemically conjugated to insulin using a carbodiimide derivative. The psoralen moiety retains its photochemical reactivity as evidenced by its ability to crosslink DNA after exposure to long wavelength ultraviolet light (UVA, 320-400 nm). This chimeric molecule has been used to selectively kill a population of lymphocytes whose expression of insulin receptors has been stimulated with phytohemagglutinin. Insulin carries the psoralen into the cell via receptor-mediated endocytosis, where it is subsequently activated by exposure to UVA light. The UVA induced activity of AMT-insulin can be blocked by the presence of native insulin. The viability of unstimulated lymphocytes was not affected by AMT-insulin and UVA light. The hybrid insulin-psoralen molecule may be a prototype for a family of phototoxic drugs which can be selectively delivered to subsets of lymphocytes.

  14. Gelidium amansii promotes dendritic spine morphology and synaptogenesis, and modulates NMDA receptor-mediated postsynaptic current.

    Science.gov (United States)

    Hannan, Md Abdul; Mohibbullah, Md; Hong, Yong-Ki; Nam, Joo Hyun; Moon, Il Soo

    2014-01-01

    Neurotrophic factors are essential for the differentiation and maturation of developing neurons as well as providing survival support to the mature neurons. Moreover, therapeutically neurotrophic factors are promising to reconstruct partially damaged neuronal networks in neurodegenerative diseases. In the previous study, we reported that the ethanol extract of an edible marine alga, Gelidium amansii (GAE) had shown promising effects in the development and maturation of both axon and dendrites of hippocampal neurons. Here, we demonstrate that in primary culture of hippocampal neurons (1) GAE promotes a significant increase in the number of filopodia and dendritic spines; (2) promotes synaptogenesis; (3) enhances N-methyl-D-aspartic acid (NMDA) receptor recruitment; and (4) modulates NMDA-receptor-mediated postsynaptic current. Taken together these findings that GAE might be involved in both morphological and functional maturation of neurons suggest the possibility that GAE may constitute a promising candidate for novel compounds for the prevention and treatment of neurodegenerative diseases.

  15. Sickle erythrocytes enhance phenylephrine and histamine

    African Journals Online (AJOL)

    Dr Olaleye

    the influence of sickle erythrocyte on contractile responses induced by phenylephrine and histamine. ... obtained from subjects of different haemoglobin (Hb) genotypes (AA, AS and SS), under ... the sixth position of the β-chain of the hemoglobin S. Address for ... blood pressure values in sickle cell anaemia subjects as.

  16. Scavenger receptors mediate the role of SUMO and Ftz-f1 in Drosophila steroidogenesis.

    Directory of Open Access Journals (Sweden)

    Ana Talamillo

    2013-04-01

    Full Text Available SUMOylation participates in ecdysteroid biosynthesis at the onset of metamorphosis in Drosophila melanogaster. Silencing the Drosophila SUMO homologue smt3 in the prothoracic gland leads to reduced lipid content, low ecdysone titers, and a block in the larval-pupal transition. Here we show that the SR-BI family of Scavenger Receptors mediates SUMO functions. Reduced levels of Snmp1 compromise lipid uptake in the prothoracic gland. In addition, overexpression of Snmp1 is able to recover lipid droplet levels in the smt3 knockdown prothoracic gland cells. Snmp1 expression depends on Ftz-f1 (an NR5A-type orphan nuclear receptor, the expression of which, in turn, depends on SUMO. Furthermore, we show by in vitro and in vivo experiments that Ftz-f1 is SUMOylated. RNAi-mediated knockdown of ftz-f1 phenocopies that of smt3 at the larval to pupal transition, thus Ftz-f1 is an interesting candidate to mediate some of the functions of SUMO at the onset of metamorphosis. Additionally, we demonstrate that the role of SUMOylation, Ftz-f1, and the Scavenger Receptors in lipid capture and mobilization is conserved in other steroidogenic tissues such as the follicle cells of the ovary. smt3 knockdown, as well as ftz-f1 or Scavenger knockdown, depleted the lipid content of the follicle cells, which could be rescued by Snmp1 overexpression. Therefore, our data provide new insights into the regulation of metamorphosis via lipid homeostasis, showing that Drosophila Smt3, Ftz-f1, and SR-BIs are part of a general mechanism for uptake of lipids such as cholesterol, required during development in steroidogenic tissues.

  17. Histamine metabolism in cluster headache and migraine. Catabolism of /sup 14/C histamine

    Energy Technology Data Exchange (ETDEWEB)

    Sjaastad, O; Sjaastad, O V

    1977-09-12

    Various parameters of histamine metabolism were studied in patients with migraine, cluster headache and chronic paroxysmal hemicrania. These included urinary excretion of radioactivity and of /sup 14/C histamine and its metabolites, exhaled /sup 14/CO/sub 2/ and fecal radioactivity after oral as well as subcutaneous administration of radioactive histamine. No marked deviation from the normal was found except in one patient with the cluster headache variant, chronic paroxysmal hemicrania, in whom an aberration in /sup 14/C histamine degradation seemed to be present. Only minute quantities of the /sup 14/C histamine metabolite C14 imidazoleacetic acid riboside seemed to be formed during a period with severe paraxysms. During a symptom-free period no deviation from normal was observed. The most likely explanation for this finding seems to be a defect in the conversion of imidazoleacetic acid to its riboside. This defect may possibly explain the increased urinary excretion of histamine in this particular patient. The relationship of this metabolic aberration to the production of headache still remains dubious for various reasons.

  18. Flavonoids inhibit histamine release and expression of proinflammatory cytokines in mast cells.

    Science.gov (United States)

    Park, Hyo-Hyun; Lee, Soyoung; Son, Hee-Young; Park, Seung-Bin; Kim, Mi-Sun; Choi, Eun-Ju; Singh, Thoudam S K; Ha, Jeoung-Hee; Lee, Maan-Gee; Kim, Jung-Eun; Hyun, Myung Chul; Kwon, Taeg Kyu; Kim, Yeo Hyang; Kim, Sang-Hyun

    2008-10-01

    Mast cells participate in allergy and inflammation by secreting inflammatory mediators such as histamine and proinflammatory cytokines. Flavonoids are naturally occurring molecules with antioxidant, cytoprotective, and antiinflammatory actions. However, effect of flavonoids on the release of histamine and proinflammatory mediator, and their comparative mechanism of action in mast cells were not well defined. Here, we compared the effect of six flavonoids (astragalin, fisetin, kaempferol, myricetin, quercetin, and rutin) on the mast cell-mediated allergic inflammation. Fisetin, kaempferol, myricetin, quercetin, and rutin inhibited IgE or phorbol-12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-mediated histamine release in RBL-2H3 cells. These five flavonoids also inhibited elevation of intracellular calcium. Gene expressions and secretion of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, and IL-8 were assessed in PMACI-stimulated human mast cells (HMC-1). Fisetin, quercetin, and rutin decreased gene expression and production of all the proinflammatory cytokines after PMACI stimulation. Myricetin attenuated TNF-alpha and IL-6 but not IL-1beta and IL-8. Fisetin, myricetin, and rutin suppressed activation of NF-kappaB indicated by inhibition of nuclear translocation of NF-kappaB, NF-kappaB/DNA binding, and NF-kappaB-dependent gene reporter assay. The pharmacological actions of these flavonoids suggest their potential activity for treatment of allergic inflammatory diseases through the down-regulation of mast cell activation.

  19. Histamine from brain resident MAST cells promotes wakefulness and modulates behavioral states.

    Directory of Open Access Journals (Sweden)

    Sachiko Chikahisa

    Full Text Available Mast cell activation and degranulation can result in the release of various chemical mediators, such as histamine and cytokines, which significantly affect sleep. Mast cells also exist in the central nervous system (CNS. Since up to 50% of histamine contents in the brain are from brain mast cells, mediators from brain mast cells may significantly influence sleep and other behaviors. In this study, we examined potential involvement of brain mast cells in sleep/wake regulations, focusing especially on the histaminergic system, using mast cell deficient (W/W(v mice. No significant difference was found in the basal amount of sleep/wake between W/W(v mice and their wild-type littermates (WT, although W/W(v mice showed increased EEG delta power and attenuated rebound response after sleep deprivation. Intracerebroventricular injection of compound 48/80, a histamine releaser from mast cells, significantly increased histamine levels in the ventricular region and enhanced wakefulness in WT mice, while it had no effect in W/W(v mice. Injection of H1 antagonists (triprolidine and mepyramine significantly increased the amounts of slow-wave sleep in WT mice, but not in W/W(v mice. Most strikingly, the food-seeking behavior observed in WT mice during food deprivation was completely abolished in W/W(v mice. W/W(v mice also exhibited higher anxiety and depression levels compared to WT mice. Our findings suggest that histamine released from brain mast cells is wake-promoting, and emphasizes the physiological and pharmacological importance of brain mast cells in the regulation of sleep and fundamental neurobehavior.

  20. Med1 subunit of the mediator complex in nuclear receptor-regulated energy metabolism, liver regeneration, and hepatocarcinogenesis.

    Science.gov (United States)

    Jia, Yuzhi; Viswakarma, Navin; Reddy, Janardan K

    2014-01-01

    Several nuclear receptors regulate diverse metabolic functions that impact on critical biological processes, such as development, differentiation, cellular regeneration, and neoplastic conversion. In the liver, some members of the nuclear receptor family, such as peroxisome proliferator-activated receptors (PPARs), constitutive androstane receptor (CAR), farnesoid X receptor (FXR), liver X receptor (LXR), pregnane X receptor (PXR), glucocorticoid receptor (GR), and others, regulate energy homeostasis, the formation and excretion of bile acids, and detoxification of xenobiotics. Excess energy burning resulting from increases in fatty acid oxidation systems in liver generates reactive oxygen species, and the resulting oxidative damage influences liver regeneration and liver tumor development. These nuclear receptors are important sensors of exogenous activators as well as receptor-specific endogenous ligands. In this regard, gene knockout mouse models revealed that some lipid-metabolizing enzymes generate PPARα-activating ligands, while others such as ACOX1 (fatty acyl-CoA oxidase1) inactivate these endogenous PPARα activators. In the absence of ACOX1, the unmetabolized ACOX1 substrates cause sustained activation of PPARα, and the resulting increase in energy burning leads to hepatocarcinogenesis. Ligand-activated nuclear receptors recruit the multisubunit Mediator complex for RNA polymerase II-dependent gene transcription. Evidence indicates that the Med1 subunit of the Mediator is essential for PPARα, PPARγ, CAR, and GR signaling in liver. Med1 null hepatocytes fail to respond to PPARα activators in that these cells do not show induction of peroxisome proliferation and increases in fatty acid oxidation enzymes. Med1-deficient hepatocytes show no increase in cell proliferation and do not give rise to liver tumors. Identification of nuclear receptor-specific coactivators and Mediator subunits should further our understanding of the complexities of metabolic

  1. The CB1 Receptor as an Important Mediator of Hedonic Reward Processing

    Science.gov (United States)

    Friemel, Chris M; Zimmer, Andreas; Schneider, Miriam

    2014-01-01

    The endocannabinoid (ECB) system has emerged recently as a key mediator for reward processing. It is well known that cannabinoids affect appetitive learning processes and can induce reinforcing and rewarding effects. However, the involvement of the ECB system in hedonic aspects of reward-related behavior is not completely understood. With the present study, we investigated the modulatory role of the ECB system on hedonic perception, measured by the pleasure attenuated startle (PAS) paradigm for a palatable food reward. Here, a conditioned odor is thought to induce a pleasant affective state that attenuates an aversive reflex—the acoustic startle response. Modulatory effects of the CB1 receptor antagonist/inverse agonist SR1411716 and the cannabinoid agonist WIN 55 212-2 on PAS were examined in rats. PAS was also measured in CB1 receptor knockout (KO) and wild-type (WT) mice. Pharmacological inhibition as well as the absence of CB1 receptors was found to reduce PAS, whereas WIN 55 212-2 administration increased PAS. Finally, presentation of a conditioned reward cue was found to induce striatal FosB/ΔFosB expression in WT mice, but not in KO mice, indicating a reduced stimulation of reward-related brain regions in conditioned KO mice by odor presentation. We here show that in addition to our previous studies in rats, PAS may also serve as a valuable and suitable measure to assess hedonic processing in mice. Our data further indicate that the ECB system, and in particular CB1 receptor signaling, appears to be highly important for the mediation of hedonic aspects of reward processing. PMID:24718372

  2. Decrement of GABAA receptor-mediated inhibitory postsynaptic currents in dentate granule cells in epileptic hippocampus.

    Science.gov (United States)

    Isokawa, M

    1996-05-01

    1. Inhibitory postsynaptic currents (IPSCs) were studied in hippocampal dentate granule cells (DGCs) in the pilocarpine model and human temporal lobe epilepsy, with the use of the whole cell patch-clamp recording technique in slice preparations. 2. In the pilocarpine model, hippocampal slices were prepared from rats that were allowed to experience spontaneous seizures for 2 mo. Human hippocampal specimens were obtained from epileptic patients who underwent surgical treatment for medically intractable seizures. 3. IPSCs were generated by single perforant path stimulation and recorded at a membrane potential (Vm) of 0 mV near the reversal potential of glutamate excitatory postsynaptic currents in the voltage-clamp recording. IPSCs were pharmacologically identified as gamma-aminobutyric acid-A (GABAA) IPSCs by 10 microM bicuculline methiodide. 4. During low-frequency stimulation, IPSCs were not different in amplitude among non-seizure-experienced rat hippocampi, human nonsclerotic hippocampi, seizure-experienced rat hippocampi, and human sclerotic hippocampi. In the last two groups of DGCs, current-clamp recordings indicated the presence of prolonged excitatory postsynaptic potentials (EPSPs) mediated by the N-methyl-D-aspartate (NMDA) receptor. 5. High-frequency stimulation, administered at Vm = -30 mV to activate NMDA currents, reduced GABAA IPSC amplitude specifically in seizure-experienced rat hippocampi (t = 2.5, P < 0.03) and human sclerotic hippocampi (t = 7.7, P < 0.01). This reduction was blocked by an NMDA receptor antagonist, 2-amino-5-phosphonovaleric acid (APV) (50 microM). The time for GABAA IPSCs to recover to their original amplitude was also shortened by the application of APV. 6. I conclude that, when intensively activated, NMDA receptor-mediated excitatory transmission may interact with GABAergic synaptic inhibition in DGCs in seizure-experienced hippocampus to transiently reduce GABA(A) receptor-channel function. Such interactions may contribute to

  3. Oxidative stress augments toll-like receptor 8 mediated neutrophilic responses in healthy subjects

    Directory of Open Access Journals (Sweden)

    Matsunaga Kazuto

    2009-06-01

    Full Text Available Abstract Background Excessive oxidative stress has been reported to be generated in inflamed tissues and contribute to the pathogenesis of inflammatory lung diseases, exacerbations of which induced by viral infections are associated with toll-like receptor (TLR activation. Among these receptors, TLR8 has been reported as a key receptor that recognizes single-strand RNA virus. However, it remains unknown whether TLR8 signaling is potentiated by oxidative stress. The aim of this study is to examine whether oxidative stress modulates TLR8 signaling in vitro. Methods Human peripheral blood neutrophils were obtained from healthy non-smokers and stimulated with TLR 7/8 agonist imidazoquinoline resiquimod (R848 in the presence or absence of hydrogen peroxide (H2O2. Neutrophilic responses including cytokine release, superoxide production and chemotaxis were examined, and the signal transduction was also analyzed. Results Activation of TLR8, but not TLR7, augmented IL-8 release. The R848-augmented IL-8 release was significantly potentiated by pretreatment with H2O2 (p L-cysteine reversed this potentiation. The combination of H2O2 and R848 significantly potentiated NF-kB phosphorylation and IkBα degradation. The H2O2-potentiated IL-8 release was suppressed by MG-132, a proteosome inhibitor, and by dexamethasone. The expressions of TLR8, myeloid differentiation primary response gene 88 (MyD88, and tumor necrosis factor receptor-associated factor 6 (TRAF6 were not affected by H2O2. Conclusion TLR8-mediated neutrophilic responses were markedly potentiated by oxidative stress, and the potentiation was mediated by enhanced NF-kB activation. These results suggest that oxidative stress might potentiate the neutrophilic inflammation during viral infection.

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

    Science.gov (United States)

    Stengel, Andreas; Taché, Yvette F

    2017-01-01

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

  5. Multifunctional pH-Responsive Folate Receptor Mediated Polymer Nanoparticles for Drug Delivery.

    Science.gov (United States)

    Cai, Xiaoqing; Yang, Xiaoye; Wang, Fang; Zhang, Chen; Sun, Deqing; Zhai, Guangxi

    2016-07-01

    Multifunctional pH-responsive folate receptor mediated targeted polymer nanoparticles (TPNps) were developed for docetaxel (DTX) delivery based on poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)poly (β-amino ester) (P123-PAE) and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)-folate (P123-FA) copolymers. The DTX was loaded into the TPNps with a decent drug loading content of 15.02 ± 0.14 wt%. In vitro drug release results showed that the DTX was released from the TPNps at a pH-dependent manner. Tetrazolium dye (MTT) assay revealed that the bland polymer nanoparticles displayed almost nontoxicity at 200 μg/mL concentration. However, the DTX-loaded TPNps showed high anti-tumor activity at low IC50 (0.72 μg/mL) for MCF-7 cells following 48 h incubation. Cellular uptake experiments revealed that the TPNps had higher degree of cellular uptake than nontargeted polymer nanoparticles, indicating that the nanoparticles were internalized into the cells via FA receptor-mediated endocytosis. Moreover, the cellular uptake pathways for the FA grafted polymer were involved in energy-dependent, clathrin-mediated and caveolae-mediated endocytosis. The cell killing effect and cellular uptake of the DTX-TPNps by the MCF-7 cells were all enhanced by about two folds at pH 5.5 when compared with pH 7.4. The TPNps also significantly prolonged the in vivo retention time for the DTX. These results suggest that the biocompatible pH responsive folate-modified polymer nanoparticles present a promising safe nanosystem for intracellular targeted delivery of DTX.

  6. Inhibition of histamine and eicosanoid release from dispersed human lung cells in vitro by quinotolast.

    Science.gov (United States)

    Okayama, Y; Hiroi, J; Lau, L C; Church, M K

    1995-12-01

    We have examined the effects of a new anti-allergic drug, quinotolast [sodium 5-(4-oxo-1-phenoxy-4H-quinolizine-3-carboxamido) yetrazolate monohydrate], in inhibiting the release of histamine and the generation of leukotriene (LT) C4 and prostaglandin (PG) D2 from dispersed human lung cells and compared this with those of its active metabolite in the rat, hydroxy quinotolast, and reference drugs, tranilast and sodium cromoglycate (SCG). Quinotolast in the concentration range of 1-100 micrograms/ml inhibited histamine and LTC4 release in a concentration-dependent manner. The inhibitory effect of quinotolast on histamine release from dispersed lung cells was largely independent of the preincubation period, no tachyphylaxis being observed. Hydroxy quinotolast and tranilast showed a weak inhibition of histamine release only when the drugs were added to the cells simultaneously with anti-IgE challenge. Quinotolast, 100 micrograms/ml, and SCG, 1 mM, significantly inhibited PGD2 and LTC4 release. Quinotolast inhibited PGD2 release by 100% and LTC4 release by 54%, whereas SCG inhibited PDG2 release by 33% and LTC4 release by 100%. No cross-tachyphylaxis between quinotolast and SCG was observed. The results demonstrated that quinotolast showed a significant inhibition of inflammatory mediators from human dispersed lung cells, suggesting that quinotolast is a good candidate for a clinical anti-allergic drug.

  7. Calcium sensing receptor as a novel mediator of adipose tissue dysfunction: mechanisms and potential clinical implications

    Directory of Open Access Journals (Sweden)

    Roberto Bravo

    2016-09-01

    Full Text Available Obesity is currently a serious worldwide public health problem, reaching pandemic levels. For decades, dietary and behavioral approaches have failed to prevent this disease from expanding, and health authorities are challenged by the elevated prevalence of co-morbid conditions. Understanding how obesity-associated diseases develop from a basic science approach is recognized as an urgent task to face this growing problem. White adipose tissue is an active endocrine organ, with a crucial influence on whole-body homeostasis. White adipose tissue dysfunction plays a key role linking obesity with its associated diseases such as type 2 diabetes mellitus, cardiovascular disease and some cancers. Among the regulators of white adipose tissue physiology, the calcium-sensing receptor has arisen as a potential mediator of white adipose tissue dysfunction. Expression of the receptor has been described in human preadipocytes, adipocytes, and the human adipose cell lines LS14 and SW872. The evidence suggests that calcium-sensing receptor activation in the visceral (i.e. unhealthy white adipose tissue is associated with an increased proliferation of adipose progenitor cells and elevated adipocyte differentiation. In addition, exposure of adipose cells to calcium-sensing receptor activators in vitro elevates proinflammatory cytokine expression and secretion. An increased proinflammatory environment in white adipose tissue plays a key role in the development of white adipose tissue dysfunction that leads to peripheral organ fat deposition and insulin resistance, among other consequences. We propose that calcium-sensing receptor may be one relevant therapeutic target in the struggle to confront the health consequences of the current worldwide obesity pandemic.

  8. The Arabidopsis flagellin receptor FLS2 mediates the perception of Xanthomonas Ax21 secreted peptides.

    Science.gov (United States)

    Danna, Cristian H; Millet, Yves A; Koller, Teresa; Han, Sang-Wook; Bent, Andrew F; Ronald, Pamela C; Ausubel, Frederick M

    2011-05-31

    Detection of microbes by plants relies in part on an array of pattern-recognition receptors that recognize conserved microbial signatures, so-called "microbe-associated molecular patterns." The Arabidopsis thaliana receptor-like kinase FLS2 is the pattern-recognition receptor for bacterial flagellin. Similarly to FLS2, the rice transmembrane protein XA21 is the receptor for the sulfated form of the Xanthomonas oryzae pv. oryzae secreted protein Ax21. Here we show that Ax21-derived peptides activate Arabidopsis immunity, triggering responses similar to those elicited by flagellin, including an oxidative burst, induction of defense-response genes, and enhanced resistance to bacterial pathogens. To identify Arabidopsis Xa21 functional homologs, we used a reverse genetics approach to screen T-DNA insertion mutants corresponding to all 47 of the Arabidopsis genes encoding non-RD kinases belonging to the interleukin-1 receptor-associated kinase (IRAK) family. Surprisingly, among all of these mutant lines, only fls2 mutants exhibited a significant loss of response to Ax21-derived peptides. Ax21 peptides also failed to activate defense-related responses in an fls2-24 mutant that does not bind Flg22. Moreover, a Flg22Δ2 variant of Flg22 that binds to FLS2 but does not activate FLS2-mediated signaling suppressed Ax21-derived peptide signaling, indicating mutually exclusive perception of Flg22 or Ax21 peptides by FLS2. The data indicate that FLS2 functions beyond flagellin perception to detect other microbe-associated molecular patterns.

  9. Influence of ER leak on resting cytoplasmic Ca2+ and receptor-mediated Ca2+ signalling in human macrophage.

    Science.gov (United States)

    Layhadi, Janice A; Fountain, Samuel J

    2017-06-03

    Mechanisms controlling endoplasmic reticulum (ER) Ca 2+ homeostasis are important regulators of resting cytoplasmic Ca 2+ concentration ([Ca 2+ ] cyto ) and receptor-mediated Ca 2+ signalling. Here we investigate channels responsible for ER Ca 2+ leak in THP-1 macrophage and human primary macrophage. In the absence of extracellular Ca 2+ we employ ionomycin action at the plasma membrane to stimulate ER Ca 2+ leak. Under these conditions ionomycin elevates [Ca 2+ ] cyto revealing a Ca 2+ leak response which is abolished by thapsigargin. IP 3 receptors (Xestospongin C, 2-APB), ryanodine receptors (dantrolene), and translocon (anisomycin) inhibition facilitated ER Ca 2+ leak in model macrophage, with translocon inhibition also reducing resting [Ca 2+ ] cyto . In primary macrophage, translocon inhibition blocks Ca 2+ leak but does not influence resting [Ca 2+ ] cyto . We identify a role for translocon-mediated ER Ca 2+ leak in receptor-mediated Ca 2+ signalling in both model and primary human macrophage, whereby the Ca 2+ response to ADP (P2Y receptor agonist) is augmented following anisomycin treatment. In conclusion, we demonstrate a role of ER Ca 2+ leak via the translocon in controlling resting cytoplasmic Ca 2+ in model macrophage and receptor-mediated Ca 2+ signalling in model macrophage and primary macrophage. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Estrogen promotes megakaryocyte polyploidization via estrogen receptor beta-mediated transcription of GATA1.

    Science.gov (United States)

    Du, C; Xu, Y; Yang, K; Chen, S; Wang, X; Wang, S; Wang, C; Shen, M; Chen, F; Chen, M; Zeng, D; Li, F; Wang, T; Wang, F; Zhao, J; Ai, G; Cheng, T; Su, Y; Wang, J

    2017-04-01

    Estrogen is reported to be involved in thrombopoiesis and the disruption of its signaling may cause myeloproliferative disease, yet the underlying mechanisms remain largely unknown. GATA-binding factor 1 (GATA1) is a key regulator of megakaryocyte (MK) differentiation and its deficiency will lead to megakaryoblastic leukemia. Here we show that estrogen can dose-dependently promote MK polyploidization and maturation via activation of estrogen receptor beta (ERβ), accompanied by a significant upregulation of GATA1. Chromatin immunoprecipitation and a dual luciferase assay demonstrate that ERβ can directly bind the promoter region of GATA1 and activate its transcription. Steroid receptor coactivator 3 (SRC3) is involved in ERβ-mediated GATA1 transcription. The deficiency of ERβ or SRC3, similar to the inhibition of GATA1, leads to the impediment of estrogen-induced MK polyploidization and platelet production. Further investigations reveal that signal transducer and activator of transcription 1 signaling pathway downstream of GATA1 has a crucial role in estrogen-induced MK polyploidization, and ERβ-mediated GATA1 upregulation subsequently enhances nuclear factor erythroid-derived 2 expression, thereby promoting proplatelet formation and platelet release. Our study provides a deep insight into the molecular mechanisms of estrogen signaling in regulating thrombopoiesis and the pathogenesis of ER deficiency-related leukemia.

  11. Receptor-mediated endocytosis of lysozyme in renal proximal tubules of the frog Rana temporaria

    Directory of Open Access Journals (Sweden)

    E.V. Seliverstova

    2015-04-01

    Full Text Available The mechanism of protein reabsorption in the kidney of lower vertebrates remains insufficiently investigated in spite of raising interest to the amphibian and fish kidneys as a useful model for physiological and pathophysiological examinations. In the present study, we examined the renal tubular uptake and the internalization rote of lysozyme after its intravenous injection in the wintering frog Rana temporaria using immunohisto- and immunocytochemistry and specific markers for some endocytic compartments. The distinct expression of megalin and cubilin in the proximal tubule cells of lysozyme-injected frogs was revealed whereas kidney tissue of control animals showed no positive immunoreactivity. Lysozyme was detected in the apical endocytic compartment of the tubular cells and colocalized with clathrin 10 min after injection. After 20 min, lysozyme was located in the subapical compartment negative to clathrin (endosomes, and intracellular trafficking of lysozyme was coincided with the distribution of megalin and cubilin. However, internalized protein was retained in the endosomes and did not reach lysosomes within 30 min after treatment that may indicate the inhibition of intracellular trafficking in hibernating frogs. For the first time, we provided the evidence that lysozyme is filtered through the glomeruli and absorbed by receptor-mediated clathrin-dependent endocytosis in the frog proximal tubule cells. Thus, the protein uptake in the amphibian mesonephros is mediated by megalin and cubilin that confirms a critical role of endocytic receptors in the renal reabsorption of proteins in amphibians as in mammals.

  12. Understanding magnetic nanoparticle osteoblast receptor-mediated endocytosis using experiments and modeling

    International Nuclear Information System (INIS)

    Tran, Nhiem; Webster, Thomas J

    2013-01-01

    Iron oxide nanoparticles are promising candidates for controlling drug delivery through an external magnetic force to treat a wide range of diseases, including osteoporosis. Previous studies have demonstrated that in the presence of hydroxyapatite coated magnetite (Fe 3 O 4 ) nanoparticles, osteoblast (or bone forming cell) proliferation and long-term functions (such as calcium deposition) were significantly enhanced. Hydroxyapatite is the major inorganic component of bone. As a further attempt to understand why, in the current study, the uptake of such nanoparticles into osteoblasts was experimentally investigated and mathematically modeled. Magnetite nanoparticles were synthesized using a co-precipitation method and were coated with hydroxyapatite. A cellular uptake experiment at low temperatures indicated that receptor-mediated endocytosis contributed to the internalization of the magnetic nanoparticles into osteoblasts. A model was further developed to explain the uptake of magnetic nanoparticles into osteoblasts using receptor-mediated endocytosis. This model may explain the internalization of hydroxyapatite into osteoblasts to elevate intracellular calcium levels necessary to promote osteoblast functions to treat a wide range of orthopedic problems, including osteoporosis. (paper)

  13. A pp32-retinoblastoma protein complex modulates androgen receptor-mediated transcription and associates with components of the splicing machinery

    International Nuclear Information System (INIS)

    Adegbola, Onikepe; Pasternack, Gary R.

    2005-01-01

    We have previously shown pp32 and the retinoblastoma protein interact. pp32 and the retinoblastoma protein are nuclear receptor transcriptional coregulators: the retinoblastoma protein is a coactivator for androgen receptor, the major regulator of prostate cancer growth, while pp32, which is highly expressed in prostate cancer, is a corepressor of the estrogen receptor. We now show pp32 increases androgen receptor-mediated transcription and the retinoblastoma protein modulates this activity. Using affinity purification and mass spectrometry, we identify members of the pp32-retinoblastoma protein complex as PSF and nonO/p54nrb, proteins implicated in coordinate regulation of nuclear receptor-mediated transcription and splicing. We show that the pp32-retinoblastoma protein complex is modulated during TPA-induced K562 differentiation. Present evidence suggests that nuclear receptors assemble multiprotein complexes to coordinately regulate transcription and mRNA processing. Our results suggest that pp32 and the retinoblastoma protein may be part of a multiprotein complex that coordinately regulates nuclear receptor-mediated transcription and mRNA processing

  14. β2-Adrenergic Receptor-Mediated HIF-1α Upregulation Mediates Blood Brain Barrier Damage in Acute Cerebral Ischemia

    Directory of Open Access Journals (Sweden)

    Yanyun Sun

    2017-08-01

    Full Text Available Disruption of the blood brain barrier (BBB within the thrombolytic time window is an antecedent event to intracerebral hemorrhage in ischemic stroke. Our recent studies showed that 2-h cerebral ischemia induced BBB damage in non-infarcted area and secreted matrix metalloproteinase-2 (MMP-2 accounted for this disruption. However, the factors that affect MMP-2 secretion and regulate BBB damage remains unknown. Since hypoxia-inducible factor-1 alpha (HIF-1α was discovered as a mater regulator in hypoxia, we sought to investigate the roles of HIF-1α in BBB damage as well as the factors regulating HIF-1α expression in the ischemic brain. in vivo rat middle cerebral artery occlusion (MCAO and in vitro oxygen glucose deprivation (OGD models were used to mimic ischemia. Pretreatment with HIF-1α inhibitor YC-1 significantly inhibited 2-h MCAO-induced BBB damage, which was accompanied by suppressed occludin degradation and vascular endothelial growth factor (VEGF mRNA upregulation. Interestingly, β2-adrenergic receptor (β2-AR antagonist ICI 118551 attenuated ischemia-induced BBB damage by regulating HIF-1α expression. Double immunostaining showed that HIF-1α was upregulated in ischemic neurons but not in astrocytes andendothelial cells. Of note, HIF-1α inhibition with inhibitor YC-1 or siRNA significantly prevented OGD-induced VEGF upregulation as well as the secretion of VEGF and MMP-2 in neurons. More importantly, blocking β2-AR with ICI 118551 suppressedHIF-1α upregulation in ischemic neurons and attenuated occludin degradation induced by the conditioned media of OGD-treatedneurons. Taken together, blockade of β2-AR-mediated HIF-1α upregulation mediates BBB damage during acute cerebral ischemia. These findings provide new mechanistic understanding of early BBB damage in ischemic stroke and may help reduce thrombolysis-related hemorrhagic complications.

  15. Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis.

    Science.gov (United States)

    Roschek, Bill; Fink, Ryan C; McMichael, Matthew; Alberte, Randall S

    2009-07-01

    A nettle (Urtica dioica) extract shows in vitro inhibition of several key inflammatory events that cause the symptoms of seasonal allergies. These include the antagonist and negative agonist activity against the Histamine-1 (H(1)) receptor and the inhibition of mast cell tryptase preventing degranulation and release of a host of pro-inflammatory mediators that cause the symptoms of hay fevers. The nettle extract also inhibits prostaglandin formation through inhibition of Cyclooxygenase-1 (COX-1), Cyclooxygenase-2 (COX-2), and Hematopoietic Prostaglandin D(2) synthase (HPGDS), central enzymes in pro-inflammatory pathways. The IC(50) value for histamine receptor antagonist activity was 251 (+/-13) microg mL(-1) and for the histamine receptor negative agonist activity was 193 (+/-71) microg mL(-1). The IC(50) values for inhibition of mast cell tryptase was 172 (+/-28) microg mL(-1), for COX-1 was 160 (+/-47) microg mL(-1), for COX-2 was 275 (+/-9) microg mL(-1), and for HPGDS was 295 (+/-51) microg mL(-1). Through the use of DART TOF-MS, which yields exact masses and relative abundances of compounds present in complex mixtures, bioactives have been identified in nettle that contribute to the inhibition of pro-inflammatory pathways related to allergic rhinitis. These results provide for the first time, a mechanistic understanding of the role of nettle extracts in reducing allergic and other inflammatory responses in vitro. Copyright 2009 John Wiley & Sons, Ltd.

  16. Potential negative effects of anti-histamines on male reproductive function.

    Science.gov (United States)

    Mondillo, Carolina; Varela, María Luisa; Abiuso, Adriana María Belén; Vázquez, Ramiro

    2018-05-01

    Histamine (HA) is a pleiotropic biogenic amine synthesized exclusively by histidine decarboxylase (HDC) in most mammalian tissues. The literature on the role of HA within the male gonad has expanded over the last years, attracting attention to potential unexpected side-effects of anti-histamines on testicular function. In this regard, HA receptors (HRH1, HRH2 and HRH4) have been described in Leydig cells of different species, including human. Via these receptors, HA has been reported to trigger positive or negative interactions with the LH/hCG signaling pathway depending upon its concentration, thereby contributing to the local control of testicular androgen levels. It should then be considered that anti-histamines may affect testicular homeostasis by increasing or decreasing steroid production. Additionally, HRH1 and HRH2 receptors are present in peritubular and germ cells, and HRH2 antagonists have been found to negatively affect peritubular cells and reduce sperm viability. The potential negative impact of anti-histamines on male reproduction becomes even more dramatic if we consider that HA has also been associated with human sexual behavior and penile erection. What is more, although testicular mast cells are the major source of locally produced HA, recent studies have described HDC expression in macrophages, Leydig cells and germ cells, revealing the existence of multiple sources of HA within the testis. Undoubtedly, the more we learn about the testicular histaminergic system, the more opportunities there will be for rational design of drugs aimed at treating HA-related pathologies, with minimum or nule negative impact on fertility. © 2018 Society for Reproduction and Fertility.

  17. Ku proteins function as corepressors to regulate farnesoid X receptor-mediated gene expression

    International Nuclear Information System (INIS)

    Ohno, Masae; Kunimoto, Masaaki; Nishizuka, Makoto; Osada, Shigehiro; Imagawa, Masayoshi

    2009-01-01

    The farnesoid X receptor (FXR; NR1H4) is a member of the nuclear receptor superfamily and regulates the expression of genes involved in enterohepatic circulation and the metabolism of bile acids. Based on functional analyses, nuclear receptors are divided into regions A-F. To explore the cofactors interacting with FXR, we performed a pull-down assay using GST-fused to the N-terminal A/B region and the C region, which are required for the ligand-independent transactivation and DNA-binding, respectively, of FXR, and nuclear extracts from HeLa cells. We identified DNA-dependent protein kinase catalytic subunit (DNA-PKcs), Ku80, and Ku70 as FXR associated factors. These proteins are known to have an important role in DNA repair, recombination, and transcription. DNA-PKcs mainly interacted with the A/B region of FXR, whereas the Ku proteins interacted with the C region and with the D region (hinge region). Chromatin immunoprecipitation assays revealed that the Ku proteins associated with FXR on the bile salt export pump (BSEP) promoter. Furthermore, we demonstrated that ectopic expression of the Ku proteins decreased the promoter activity and expression of BSEP gene mediated by FXR. These results suggest that the Ku proteins function as corepressors for FXR.

  18. Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

    Directory of Open Access Journals (Sweden)

    Stephan Schmidt

    2015-05-01

    Full Text Available Many biological functions at cell level are mediated by the glycocalyx, a dense carbohydrate-presenting layer. In this layer specific interactions between carbohydrate ligands and protein receptors are formed to control cell–cell recognition, cell adhesion and related processes. The aim of this work is to shed light on the principles of complex formation between surface anchored carbohydrates and receptor surfaces by measuring the specific adhesion between surface bound mannose on a concanavalin A (ConA layer via poly(ethylene glycol-(PEG-based soft colloidal probes (SCPs. Special emphasis is on the dependence of multivalent presentation and density of carbohydrate units on specific adhesion. Consequently, we first present a synthetic strategy that allows for controlled density variation of functional groups on the PEG scaffold using unsaturated carboxylic acids (crotonic acid, acrylic acid, methacrylic acid as grafting units for mannose conjugation. We showed by a range of analytic techniques (ATR–FTIR, Raman microscopy, zeta potential and titration that this synthetic strategy allows for straightforward variation in grafting density and grafting length enabling the controlled presentation of mannose units on the PEG network. Finally we determined the specific adhesion of PEG-network-conjugated mannose units on ConA surfaces as a function of density and grafting type. Remarkably, the results indicated the absence of a molecular-level enhancement of mannose/ConA interaction due to chelate- or subsite-binding. The results seem to support the fact that weak carbohydrate interactions at mechanically flexible interfaces hardly undergo multivalent binding but are simply mediated by the high number of ligand–receptor interactions.

  19. Cobaltous chloride and hypoxia inhibit aryl hydrocarbon receptor-mediated responses in breast cancer cells

    International Nuclear Information System (INIS)

    Khan, Shaheen; Liu Shengxi; Stoner, Matthew; Safe, Stephen

    2007-01-01

    The aryl hydrocarbon receptor (AhR) is expressed in estrogen receptor (ER)-positive ZR-75 breast cancer cells. Treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces CYP1A1 protein and mRNA levels and also activates inhibitory AhR-ERα crosstalk associated with hormone-induced reporter gene expression. In ZR-75 cells grown under hypoxia, induction of these AhR-mediated responses by TCDD was significantly inhibited. This was not accompanied by decreased nuclear AhR levels or decreased interaction of the AhR complex with the CYP1A1 gene promoter as determined in a chromatin immunoprecipitation assay. Hypoxia-induced loss of Ah-responsiveness was not associated with induction of hypoxia-inducible factor-1α or other factors that sequester the AhR nuclear translocation (Arnt) protein, and overexpression of Arnt under hypoxia did not restore Ah-responsiveness. The p65 subunit of NFκB which inhibits AhR-mediated transactivation was not induced by hypoxia and was primarily cytosolic in ZR-75 cells grown under hypoxic and normoxic conditions. In ZR-75 cells maintained under hypoxic conditions for 24 h, BRCA1 (an enhancer of AhR-mediated transactivation in breast cancer cells) was significantly decreased and this contributed to loss of Ah-responsiveness. In cells grown under hypoxia for 6 h, BRCA1 was not decreased, but induction of CYP1A1 by TCDD was significantly decreased. Cotreatment of ZR-75 cells with TCDD plus the protein synthesis inhibitor cycloheximide for 6 h enhanced CYP1A1 expression in cells grown under hypoxia and normoxia. These results suggest that hypoxia rapidly induces protein(s) that inhibit Ah-responsiveness and these may be similar to constitutively expressed inhibitors of Ah-responsiveness (under normoxia) that are also inhibited by cycloheximide

  20. Ran GTPase promotes cancer progression via Met receptor-mediated downstream signaling

    Science.gov (United States)

    Yuen, Hiu-Fung; Chan, Ka-Kui; Platt-Higgins, Angela; Dakir, El-Habib; Matchett, Kyle B.; Haggag, Yusuf Ahmed; Jithesh, Puthen V.; Habib, Tanwir; Faheem, Ahmed; Dean, Fennell A.; Morgan, Richard; Rudland, Philip S.; El-Tanani, Mohamed

    2016-01-01

    It has been shown previously that cancer cells with an activated oncogenic pathway, including Met activation, require Ran for growth and survival. Here, we show that knockdown of Ran leads to a reduction of Met receptor expression in several breast and lung cancer cell lines. This, in turn suppressed HGF expression and the Met-mediated activation of the Akt pathway, as well as cell adhesion, migration, and invasion. In a cell line model where Met amplification has previously been shown to contribute to gefitinib resistance, Ran knockdown sensitized cells to gefitinib-mediated inhibition of Akt and ERK1/2 phosphorylation and consequently reduced cell proliferation. We further demonstrate that Met reduction-mediated by knockdown of Ran, occurs at the post-transcriptional level, probably via a matrix metalloproteinase. Moreover, the level of immunoreactive Ran and Met are positively associated in human breast cancer specimens, suggesting that a high level of Ran may be a pre-requisite for Met overexpression. Interestingly, a high level of immunoreactive Ran dictates the prognostic significance of Met, indicating that the co-overexpression of Met and Ran may be associated with cancer progression and could be used in combination as a prognostic indicator. PMID:27716616

  1. MDMA-Induced Dissociative State not Mediated by the 5-HT2A Receptor

    Directory of Open Access Journals (Sweden)

    Drew J. Puxty

    2017-07-01

    Full Text Available Previous research has shown that a single dose of MDMA induce a dissociative state, by elevating feelings of depersonalization and derealization. Typically, it is assumed that action on the 5-HT2A receptor is the mechanism underlying these psychedelic experiences. In addition, other studies have shown associations between dissociative states and biological parameters (heart rate, cortisol, which are elevated by MDMA. In order to investigate the role of the 5-HT2 receptor in the MDMA-induced dissociative state and the association with biological parameters, a placebo-controlled within-subject study was conducted including a single oral dose of MDMA (75 mg, combined with placebo or a single oral dose of the 5-HT2 receptor blocker ketanserin (40 mg. Twenty healthy recreational MDMA users filled out a dissociative states scale (CADSS 90 min after treatments, which was preceded and followed by assessment of a number of biological parameters (cortisol levels, heart rate, MDMA blood concentrations. Findings showed that MDMA induced a dissociative state but this effect was not counteracted by pre-treatment with ketanserin. Heart rate was the only biological parameter that correlated with the MDMA-induced dissociative state, but an absence of correlation between these measures when participants were pretreated with ketanserin suggests an absence of directional effects of heart rate on dissociative state. It is suggested that the 5-HT2 receptor does not mediate the dissociative effects caused by a single dose of MDMA. Further research is needed to determine the exact neurobiology underlying this effect and whether these effects contribute to the therapeutic potential of MDMA.

  2. Serotonin₂A/C receptors mediate the aggressive phenotype of TLX gene knockout mice.

    Science.gov (United States)

    Juárez, Pablo; Valdovinos, Maria G; May, Michael E; Lloyd, Blair P; Couppis, Maria H; Kennedy, Craig H

    2013-11-01

    Deleting the tailless (TLX) gene in mice produces a highly aggressive phenotype yet to be characterized in terms of heterozygous animals or neurotransmitter mechanisms. We sought to establish pharmacological control over aggression and study the role of serotonin (5-HT)(2A/C) receptors in mediating changes in aggression. We analyzed aggression in mice heterozygous (+/-) or homozygous (-/-) for the TLX gene and wild-types (+/+) using a resident-intruder paradigm. No +/+ mice were aggressive, 36% of +/- TLX and 100% of -/- TLX mice showed aggression. Dose-effect functions were established for clozapine (0.1-1.5mg/kg, ip), ketanserin (0.3-1.25 mg/kg, ip), and (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane [(±)DOI] (0.5-2.0 mg/kg, ip). Injecting clozapine decreased the frequency and duration of attacks for +/- TLX and -/- TLX mice. Clozapine did not decrease grooming in either +/- TLX or -/- TLX mice but may have increased locomotion for -/- TLX mice. Injecting ketanserin, a 5-HT(2A/C) receptor antagonist, produced differential decreases in frequency and latency to aggression between genotypes and corresponding increases in locomotor behavior. Injecting (±)DOI, a 5-HT(2A/C) receptor agonist, increased the frequency and duration of attacks, decreased the latency to attacks, and decreased locomotion in +/- and -/- TLX mice. Results of the current study suggest aggression displayed by TLX null and heterozygous mice involves 5-HT(2A/C) receptors. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. MEL-18 loss mediates estrogen receptor-α downregulation and hormone independence.

    Science.gov (United States)

    Lee, Jeong-Yeon; Won, Hee-Young; Park, Ji-Hye; Kim, Hye-Yeon; Choi, Hee-Joo; Shin, Dong-Hui; Kang, Ju-Hee; Woo, Jong-Kyu; Oh, Seung-Hyun; Son, Taekwon; Choi, Jin-Woo; Kim, Sehwan; Kim, Hyung-Yong; Yi, Kijong; Jang, Ki-Seok; Oh, Young-Ha; Kong, Gu

    2015-05-01

    The polycomb protein MEL-18 has been proposed as a tumor suppressor in breast cancer; however, its functional relevance to the hormonal regulation of breast cancer remains unknown. Here, we demonstrated that MEL-18 loss contributes to the hormone-independent phenotype of breast cancer by modulating hormone receptor expression. In multiple breast cancer cohorts, MEL-18 was markedly downregulated in triple-negative breast cancer (TNBC). MEL-18 expression positively correlated with the expression of luminal markers, including estrogen receptor-α (ER-α, encoded by ESR1). MEL-18 loss was also associated with poor response to antihormonal therapy in ER-α-positive breast cancer. Furthermore, whereas MEL-18 loss in luminal breast cancer cells resulted in the downregulation of expression and activity of ER-α and the progesterone receptor (PR), MEL-18 overexpression restored ER-α expression in TNBC. Consistently, in vivo xenograft experiments demonstrated that MEL-18 loss induces estrogen-independent growth and tamoxifen resistance in luminal breast cancer, and that MEL-18 overexpression confers tamoxifen sensitivity in TNBC. MEL-18 suppressed SUMOylation of the ESR1 transactivators p53 and SP1, thereby driving ESR1 transcription. MEL-18 facilitated the deSUMOylation process by inhibiting BMI-1/RING1B-mediated ubiquitin-proteasomal degradation of SUMO1/sentrin-specific protease 1 (SENP1). These findings demonstrate that MEL-18 is a SUMO-dependent regulator of hormone receptors and suggest MEL-18 expression as a marker for determining the antihormonal therapy response in patients with breast cancer.

  4. Receptor-mediated endocytosis of low density lipoproteins in aortic endothelial cells

    International Nuclear Information System (INIS)

    Sanan, D.A.

    1986-04-01

    Lipoprotein binding and metabolism in actively-dividing (subconfluent) and quiescent (postconfluent) bovine aortic endothelial cells (ECs) were qualitatively investigated by fluorescence microscopy using dioctadecylindocarbocyanine-labelled lipoproteins and by indirect immunofluorescence microscopy. LDL and acetylated-LDL (AcLDL) were seen bound to the surfaces of subconfluent ECs (at 4 degrees C or at 37 degrees C), as a random distribution of punctate foci. ECs therefore closely resembled fibroblasts in the distribution of LDL receptors on their surfaces. No binding of LDL was seen on postconfluent EC surfaces by either direct or indirect fluorescence microscopy. The patterns of AcLDL binding on postconfluent ECs resembled those on subconfluent ECs. Intracellular LDL and AcLDL occurred as perinuclear accumulations of large fluorescent disc-shaped profiles in subconfluent ECs. These accumulations were shown to arise from surface-bound material by pulse-chase experiments. Intracellular LDL was absent in the majority of postconfluent ECs, while AcLDL accumulation was massive. 'Wounding' of cultures allowed simultaneous assessment of lipoprotein metabolism in quiescent and actively-dividing areas of the same culture. It is concluded that postconfluent quiescent bovine aortic ECs in vitro metabolise virtually no LDL via the LDL-receptor pathway due to a vanishingly low number of LDL receptors. This contrasts with the ability of postconfluent cells to metabolise relatively large amounts of AcLDL via a receptor-mediated mechanism. The significance of these conclusions is discussed with respect to the interaction of plasma lipoproteins with the endothelium in vivo. 301 refs

  5. Facilitating effect of histamine on spatial memory deficits induced by dizocilpine as evaluated by 8-arm radial maze in SD rats%组胺对地佐环平诱发的SD大鼠八臂迷宫空间记忆障碍的改善作用

    Institute of Scientific and Technical Information of China (English)

    黄育文; 陈忠; 胡薇薇; 张力三; 吴炜; 应力阳; 魏尔清

    2003-01-01

    AIM: To investigate whether or not histamine is involved in spatial memory deficits induced by dizocilpine (MK 801) as evaluated by 8-arm radial maze of rats. METHODS: 8-Arm (4-arm baited) radial maze was used to measure spatial memory in rats. RESULTS: Bilaterally intrahippocampal (ih) injection of MK-801 (0.3 μg/site) impaired working memory and reference memory in rats. Both histamine (50, 100 ng/site, ih) and intraperitoneal (ip) injection of histidine (100, 200 mg/kg) markedly improved the spatial memory deficits induced by MK-801. On the other hand, the ameliorating effect of histidine (100 mg/kg, ip) was completely antagonized by αfluoromethylhistidine (α-FMH, 5 μg/site, ih), a potent and selective histidine decarboxylase (HDC) inhibitor, and H1-antagonist pyrilamine (1 μg/site, ih), but not by H2-antagonist cimetidine, even at a high dose (2.5 μg/site, ih).CONCLUSION: The hippocampal histamine plays an important role in the ameliorating effect on MK-801-induced spatial memory deficits, and its action is mediated through postsynaptic H1-receptor.

  6. Radioenzymatic assay for measurement of tissue concentrations of histamine: adaptation to correct for adherence of histamine to mechanical homogenizers

    International Nuclear Information System (INIS)

    Brown, J.K.; Frey, M.J.; Reed, B.R.; Leff, A.R.; Shields, R.; Gold, W.M.

    1984-01-01

    Because adherence of histamine to glass is well-known, we tested for its adherence to a mechanical homogenizer commonly used in the extraction of histamine from tissue samples. During 60 sec of homogenization, 15% to 17% of the histamine originally present in the samples ''disappeared,'' and the reason for the disappearance was reversible binding of histamine to the homogenizer. Adding trace amounts of [ 14 C]histamine to each sample before homogenization and measuring the disappearance of radioactivity during homogenization permitted correction for binding to the homogenizer. This technique for correction was validated by the measurement of endogenous concentrations of histamine in the tracheal posterior membranes of six dogs (range of mean concentrations: 0.63 to 1.51 ng/mg wet weight) followed by the measurement of known amounts of exogenous histamine added before homogenization to tracheal tissue samples from the same dogs. In the latter samples, 96 +/- 13% (mean +/- SEM) of the histamine added was measured by our technique. We conclude that binding of histamine to mechanical homogenizers may be an important cause of inaccuracy of the enzymatic assay for the measurement of histamine concentrations in tissue but that such binding may but that such binding may be easily corrected for

  7. Distinctive Modulation of Dopamine Release in the Nucleus Accumbens Shell Mediated by Dopamine and Acetylcholine Receptors.

    Science.gov (United States)

    Shin, Jung Hoon; Adrover, Martin F; Alvarez, Veronica A

    2017-11-15

    Nucleus accumbens (NAc) shell shows unique dopamine (DA) signals in vivo and plays a unique role in DA-dependent behaviors such as reward-motivated learning and the response to drugs of abuse. A disynaptic mechanism for DA release was reported and shown to require synchronized firing of cholinergic interneurons (CINs) and activation of nicotinic acetylcholine (ACh) receptors (nAChRs) in DA neuron (DAN) axons. The properties of this disynaptic mechanism of DA transmission are not well understood in the NAc shell. In this study, in vitro fast-scan cyclic voltammetry was used to examine the modulation of DA transmission evoked by CINs firing in the shell of mice and compared with other striatal regions. We found that DA signals in the shell displayed significant degree of summation in response to train stimulation of CINs, contrary to core and dorsal striatum. The summation was amplified by a D2-like receptor antagonist and experiments with mice with targeted deletion of D2 receptors to DANs or CINs revealed that D2 receptors in CINs mediate a fast inhibition observed within 100 ms of the first pulse, whereas D2 autoreceptors in DAN terminals are engaged in a slower inhibition that peaks at ∼500 ms. ACh also contributes to the use-dependent inhibition of DA release through muscarinic receptors only in the shell, where higher activity of acetylcholinesterase minimizes nAChR desensitization and promotes summation. These findings show that DA signals are modulated differentially by endogenous DA and ACh in the shell, which may underlie the unique features of shell DA signals in vivo SIGNIFICANCE STATEMENT The present study reports that dopamine (DA) release evoked by activation of cholinergic interneurons displays a high degree of summation in the shell and shows unique modulation by endogenous DA and acetylcholine. Desensitization of nicotinic receptors, which is a prevailing mechanism for use-dependent inhibition in the nucleus accumbens core and dorsal striatum, is

  8. Presynaptic CRF1 Receptors Mediate the Ethanol Enhancement of GABAergic Transmission in the Mouse Central Amygdala

    Directory of Open Access Journals (Sweden)

    Zhiguo Nie

    2009-01-01

    Full Text Available Corticotropin-releasing factor (CRF is a 41-amino-acid neuropeptide involved in stress responses initiated from several brain areas, including the amygdala formation. Research shows a strong relationship between stress, brain CRF, and excessive alcohol consumption. Behavioral studies suggest that the central amygdala (CeA is significantly involved in alcohol reward and dependence. We recently reported that the ethanol augmentation of GABAergic synaptic transmission in rat CeA involves CRF1 receptors, because both CRF and ethanol significantly enhanced the amplitude of evoked GABAergic inhibitory postsynaptic currents (IPSCs in CeA neurons from wild-type (WT and CRF2 knockout (KO mice, but not in neurons of CRF1 KO mice. The present study extends these findings using selective CRF receptor ligands, gene KO models, and miniature IPSC (mIPSC analysis to assess further a presynaptic role for the CRF receptors in mediating ethanol effects in the CeA. In whole-cell patch recordings of pharmacologically isolated GABAAergic IPSCs from slices of mouse CeA, both CRF and ethanol augmented evoked IPSCs in a concentration-dependent manner, with low EC50s. A CRF1 (but not CRF2 KO construct and the CRF1-selective nonpeptide antagonist NIH-3 (LWH-63 blocked the augmenting effect of both CRF and ethanol on evoked IPSCs. Furthermore, the new selective CRF1 agonist stressin1, but not the CRF2 agonist urocortin 3, also increased evoked IPSC amplitudes. Both CRF and ethanol decreased paired-pulse facilitation (PPF of evoked IPSCs and significantly enhanced the frequency, but not the amplitude, of spontaneous miniature GABAergic mIPSCs in CeA neurons of WT mice, suggesting a presynaptic site of action. The PPF effect of ethanol was abolished in CeA neurons of CRF1 KO mice. The CRF1 antagonist NIH-3 blocked the CRF- and ethanol-induced enhancement of mIPSC frequency in CeA neurons. These data indicate that presynaptic CRF1 receptors play a critical role in permitting

  9. Adenosine A2A receptor-dependent proliferation of pulmonary endothelial cells is mediated through calcium mobilization, PI3-kinase and ERK1/2 pathways

    International Nuclear Information System (INIS)

    Ahmad, Aftab; Schaack, Jerome B.; White, Carl W.; Ahmad, Shama

    2013-01-01

    Highlights: •A 2A receptor-induced pulmonary endothelial growth is mediated by PI3K and ERK1/2. •Cytosolic calcium mobilization is also critical for pulmonary endothelial growth. •Effectors of A 2A receptor, like tyrosine kinases and cAMP increase PI3K/Akt signaling. •Activation of A 2A receptor can contribute to vascular remodeling. -- Abstract: Hypoxia and HIF-2α-dependent A 2A receptor expression and activation increase proliferation of human lung microvascular endothelial cells (HLMVECs). This study was undertaken to investigate the signaling mechanisms that mediate the proliferative effects of A 2A receptor. A 2A receptor-mediated proliferation of HLMVECs was inhibited by intracellular calcium chelation, and by specific inhibitors of ERK1/2 and PI3-kinase (PI3K). The adenosine A 2A receptor agonist CGS21680 caused intracellular calcium mobilization in controls and, to a greater extent, in A 2A receptor-overexpressing HLMVECs. Adenoviral-mediated A 2A receptor overexpression as well as receptor activation by CGS21680 caused increased PI3K activity and Akt phosphorylation. Cells overexpressing A 2A receptor also manifested enhanced ERK1/2 phosphorylation upon CGS21680 treatment. A 2A receptor activation also caused enhanced cAMP production. Likewise, treatment with 8Br-cAMP increased PI3K activity. Hence A 2A receptor-mediated cAMP production and PI3K and Akt phosphorylation are potential mediators of the A 2A -mediated proliferative response of HLMVECs. Cytosolic calcium mobilization and ERK1/2 phosphorylation are other critical effectors of HLMVEC proliferation and growth. These studies underscore the importance of adenosine A 2A receptor in activation of survival and proliferative pathways in pulmonary endothelial cells that are mediated through PI3K/Akt and ERK1/2 pathways

  10. Shc adaptor proteins are key transducers of mitogenic signaling mediated by the G protein-coupled thrombin receptor

    DEFF Research Database (Denmark)

    Chen, Y; Grall, D; Salcini, A E

    1996-01-01

    The serine protease thrombin activates G protein signaling systems that lead to Ras activation and, in certain cells, proliferation. Whereas the steps leading to Ras activation by G protein-coupled receptors are not well defined, the mechanisms of Ras activation by receptor tyrosine kinases have......-insensitive proteins appear to mediate this effect, since (i) pertussis toxin pre-treatment of cells does not blunt the action of thrombin and (ii) Shc phosphorylation on tyrosine can be stimulated by the muscarinic m1 receptor. Shc phosphorylation does not appear to involve protein kinase C, since the addition of 4...

  11. The overexpressed human 46-kDa mannose 6-phosphate receptor mediates endocytosis and sorting of β-glucuronidase

    International Nuclear Information System (INIS)

    Watanabe, H.; Grubb, J.H.; Sly, W.S.

    1990-01-01

    The authors studied the function of the human small (46-kDa) mannose 6-phosphate receptor (SMPR) in transfected mouse L cells that do not express the larger insulin-like growth factor II/mannose 6-phosphate receptor. Cells overexpressing human SMPR were studied for enzyme binding to cell surface receptors, for binding to intracellular receptors in permeabilized cells, and for receptor-mediated endocytosis of recombinant human β-glucuronidase. Specific binding to human SMPR in permeabilized cells showed a pH optimum between pH 6.0 and pH 6.5. Binding was significant in the present of EDTA but was enhanced by added divalent cations. Up to 2.3% of the total functional receptor could be detected on the cell surface by enzyme binding. They present experiments showing that at very high levels of overexpression, and at pH 6.5, human SMPR mediated the endocytosis of β-glucuronidase. At pH 7.5, the rate of endocytosis was only 14% the rate seen at pH 6.5. Cells overexpressing human SMPR also showed reduced secretion of newly synthesized β-glucuronidase when compared to cells transfected with vector only, suggesting that overexpressed human SMPR can participate in sorting of newly synthesized β-glucuronidase and partially correct the sorting defect in mouse L cells that do not express the insulin-like growth factor II/mannose 6-phosphate receptor

  12. 3H-histamine release from human leukocytes

    International Nuclear Information System (INIS)

    Stahl Skov, P.; Norn, S.; Weeke, B.

    1979-01-01

    A rapid, simple, and inexpensive method for large scale screening of patients suspected of type I allergy has been developed. The method is based on in vitro incorporation of 3 H-histamine in the leukocytes of the patient, whereafter release of labelled histamine is measured after provocation of the cells with the suspected allergen. The new method was compared with the conventional basophil histamine release technique by in vitro provocation of six asthmatic patients under suspicion of type I allergy against animal dander, house dust, and mite, and an almost identical release of histamine was observed in both assays. (author)

  13. Antiallergic effects of H1-receptor antagonists.

    Science.gov (United States)

    Baroody, F M; Naclerio, R M

    2000-01-01

    The primary mechanism of antihistamine action in the treatment of allergic diseases is believed to be competitive antagonism of histamine binding to cellular receptors (specifically, the H1-receptors), which are present on nerve endings, smooth muscles, and glandular cells. This notion is supported by the fact that structurally unrelated drugs antagonize the H1-receptor and provide clinical benefit. However, H1-receptor antagonism may not be their sole mechanism of action in treating allergic rhinitis. On the basis of in vitro and animal experiments, drugs classified as H1-receptor antagonists have long been recognized to have additional pharmacological properties. Most first-generation H1-antihistamines have anticholinergic, sedative, local anaesthetic, and anti-5-HT effects, which might favourably affect the symptoms of the allergic response but also contribute to side-effects. These additional properties are not uniformly distributed among drugs classified as H1-receptor antagonists. Azatadine, for example, inhibits in vitro IgE-mediated histamine and leukotriene (LT) release from mast cells and basophils. In human challenge models, terfenadine, azatadine, and loratadine reduce IgE-mediated histamine release. Cetirizine reduces eosinophilic infiltration at the site of antigen challenge in the skin, but not the nose. In a nasal antigen challenge model, cetirizine pretreatment did not affect the levels of histamine and prostaglandin D2 recovered in postchallenge lavages, whereas the levels of albumin, N-tosyl-L-arginine methyl ester (TAME) esterase activity, and LTs were reduced. Terfenadine, cetirizine, and loratadine blocked allergen-induced hyperresponsiveness to methacholine. In view of the complexity of the pathophysiology of allergy, a number of H1 antagonists with additional properties are currently under development for allergic diseases. Mizolastine, a new H1-receptor antagonist, has been shown to have additional actions that should help reduce the

  14. Transmembrane α-Helix 2 and 7 Are Important for Small Molecule-Mediated Activation of the GLP-1 Receptor

    DEFF Research Database (Denmark)

    Underwood, Christina Rye; Møller Knudsen, Sanne; Schjellerup Wulff, Birgitte

    2011-01-01

    Glucagon-like peptide-1 (GLP-1) activates the GLP-1 receptor (GLP-1R), which belongs to family B of the G-protein-coupled receptors. We previously identified a selective small molecule ligand, compound 2, that acted as a full agonist and allosteric modulator of GLP-1R. In this study, the structur......Glucagon-like peptide-1 (GLP-1) activates the GLP-1 receptor (GLP-1R), which belongs to family B of the G-protein-coupled receptors. We previously identified a selective small molecule ligand, compound 2, that acted as a full agonist and allosteric modulator of GLP-1R. In this study......, the structurally related small molecule, compound 3, stimulated cAMP production from GLP-1R, but not from the homologous glucagon receptor (GluR). The receptor selectivity encouraged a chimeric receptor approach to identify domains important for compound 3-mediated activation of GLP-1R. A subsegment of the GLP-1R...... transmembrane domain containing TM2 to TM5 was sufficient to transfer compound 3 responsiveness to GluR. Therefore, divergent residues in this subsegment of GLP-1R and GluR are responsible for the receptor selectivity of compound 3. Functional analyses of other chimeric receptors suggested that the existence...

  15. IMPDHII Protein Inhibits Toll-like Receptor 2-mediated Activation of NF-κB*

    Science.gov (United States)

    Toubiana, Julie; Rossi, Anne-Lise; Grimaldi, David; Belaidouni, Nadia; Chafey, Philippe; Clary, Guilhem; Courtine, Emilie; Pene, Frederic; Mira, Jean-Paul; Claessens, Yann-Erick; Chiche, Jean-Daniel

    2011-01-01

    Toll-like receptor 2 (TLR2) plays an essential role in innate immunity by the recognition of a large variety of pathogen-associated molecular patterns. It induces its recruitment to lipid rafts induces the formation of a membranous activation cluster necessary to enhance, amplify, and control downstream signaling. However, the exact composition of the TLR2-mediated molecular complex is unknown. We performed a proteomic analysis in lipopeptide-stimulated THP1 and found IMPDHII protein rapidly recruited to lipid raft. Whereas IMPDHII is essential for lymphocyte proliferation, its biologic function within innate immune signal pathways has not been established yet. We report here that IMPDHII plays an important role in the negative regulation of TLR2 signaling by modulating PI3K activity. Indeed, IMPDHII increases the phosphatase activity of SHP1, which participates to the inactivation of PI3K. PMID:21460227

  16. Autoimmunity in Arabidopsis acd11 Is Mediated by Epigenetic Regulation of an Immune Receptor

    DEFF Research Database (Denmark)

    Palma, K.; Thorgrimsen, S.; Malinovsky, F.G.

    2010-01-01

    Certain pathogens deliver effectors into plant cells to modify host protein targets and thereby suppress immunity. These target modifications can be detected by intracellular immune receptors, or Resistance (R) proteins, that trigger strong immune responses including localized host cell death....... The accelerated cell death 11 (acd11) "lesion mimic" mutant of Arabidopsis thaliana exhibits autoimmune phenotypes such as constitutive defense responses and cell death without pathogen perception. ACD11 encodes a putative sphingosine transfer protein, but its precise role during these processes is unknown......, and that cell death in other lesion mimic mutants may also be caused by inappropriate activation of R genes. Moreover, SDG8 is required for basal and R protein-mediated pathogen resistance in Arabidopsis, revealing the importance of chromatin remodeling as a key process in plant innate immunity....

  17. REST mediates androgen receptor actions on gene repression and predicts early recurrence of prostate cancer

    DEFF Research Database (Denmark)

    Svensson, Charlotte; Ceder, Jens; Iglesias Gato, Diego

    2014-01-01

    The androgen receptor (AR) is a key regulator of prostate tumorgenesis through actions that are not fully understood. We identified the repressor element (RE)-1 silencing transcription factor (REST) as a mediator of AR actions on gene repression. Chromatin immunoprecipitation showed that AR binds...... in cell cycle progression, including Aurora Kinase A, that has previously been implicated in the growth of NE-like castration-resistant tumors. The analysis of prostate cancer tissue microarrays revealed that tumors with reduced expression of REST have higher probability of early recurrence, independently...... of their Gleason score. The demonstration that REST modulates AR actions in prostate epithelia and that REST expression is negatively correlated with disease recurrence after prostatectomy, invite a deeper characterization of its role in prostate carcinogenesis....

  18. Endoglin-mediated suppression of prostate cancer invasion is regulated by activin and bone morphogenetic protein type II receptors.

    Directory of Open Access Journals (Sweden)

    Michael J Breen

    Full Text Available Mortality from prostate cancer (PCa is due to the formation of metastatic disease. Understanding how that process is regulated is therefore critical. We previously demonstrated that endoglin, a type III transforming growth factor β (TGFβ superfamily receptor, suppresses human PCa cell invasion and metastasis. Endoglin-mediated suppression of invasion was also shown by us to be dependent upon the type I TGFβ receptor, activin receptor-like kinase 2 (ALK2, and the downstream effector, Smad1. In this study we demonstrate for the first time that two type II TGFβ receptors are required for endoglin-mediated suppression of invasion: activin A receptor type IIA (ActRIIA and bone morphogenetic protein receptor type II (BMPRII. Downstream signaling through these receptors is predominantly mediated by Smad1. ActRIIA stimulates Smad1 activation in a kinase-dependent manner, and this is required for suppression of invasion. In contrast BMPRII regulates Smad1 in a biphasic manner, promoting Smad1 signaling through its kinase domain but suppressing it through its cytoplasmic tail. BMPRII's Smad1-regulatory effects are dependent upon its expression level. Further, its ability to suppress invasion is independent of either kinase function or tail domain. We demonstrate that ActRIIA and BMPRII physically interact, and that each also interacts with endoglin. The current findings demonstrate that both BMPRII and ActRIIA are necessary for endoglin-mediated suppression of human PCa cell invasion, that they have differential effects on Smad1 signaling, that they make separate contributions to regulation of invasion, and that they functionally and physically interact.

  19. Astrocytes protect neurons against methylmercury via ATP/P2Y(1) receptor-mediated pathways in astrocytes.

    Science.gov (United States)

    Noguchi, Yusuke; Shinozaki, Youichi; Fujishita, Kayoko; Shibata, Keisuke; Imura, Yoshio; Morizawa, Yosuke; Gachet, Christian; Koizumi, Schuichi

    2013-01-01

    Methylmercury (MeHg) is a well known environmental pollutant that induces serious neuronal damage. Although MeHg readily crosses the blood-brain barrier, and should affect both neurons and glial cells, how it affects glia or neuron-to-glia interactions has received only limited attention. Here, we report that MeHg triggers ATP/P2Y1 receptor signals in astrocytes, thereby protecting neurons against MeHg via interleukin-6 (IL-6)-mediated pathways. MeHg increased several mRNAs in astrocytes, among which IL-6 was the highest. For this, ATP/P2Y1 receptor-mediated mechanisms were required because the IL-6 production was (i) inhibited by a P2Y1 receptor antagonist, MRS2179, (ii) abolished in astrocytes obtained from P2Y1 receptor-knockout mice, and (iii) mimicked by exogenously applied ATP. In addition, (iv) MeHg released ATP by exocytosis from astrocytes. As for the intracellular mechanisms responsible for IL-6 production, p38 MAP kinase was involved. MeHg-treated astrocyte-conditioned medium (ACM) showed neuro-protective effects against MeHg, which was blocked by anti-IL-6 antibody and was mimicked by the application of recombinant IL-6. As for the mechanism of neuro-protection by IL-6, an adenosine A1 receptor-mediated pathway in neurons seems to be involved. Taken together, when astrocytes sense MeHg, they release ATP that autostimulates P2Y1 receptors to upregulate IL-6, thereby leading to A1 receptor-mediated neuro-protection against MeHg.

  20. The brain cytoplasmic RNA BC1 regulates dopamine D2 receptor-mediated transmission in the striatum.

    Science.gov (United States)

    Centonze, Diego; Rossi, Silvia; Napoli, Ilaria; Mercaldo, Valentina; Lacoux, Caroline; Ferrari, Francesca; Ciotti, Maria Teresa; De Chiara, Valentina; Prosperetti, Chiara; Maccarrone, Mauro; Fezza, Filomena; Calabresi, Paolo; Bernardi, Giorgio; Bagni, Claudia

    2007-08-15

    Dopamine D(2) receptor (D(2)DR)-mediated transmission in the striatum is remarkably flexible, and changes in its efficacy have been heavily implicated in a variety of physiological and pathological conditions. Although receptor-associated proteins are clearly involved in specific forms of synaptic plasticity, the molecular mechanisms regulating the sensitivity of D(2) receptors in this brain area are essentially obscure. We have studied the physiological responses of the D(2)DR stimulations in mice lacking the brain cytoplasmic RNA BC1, a small noncoding dendritically localized RNA that is supposed to play a role in mRNA translation. We show that the efficiency of D(2)-mediated transmission regulating striatal GABA synapses is under the control of BC1 RNA, through a negative influence on D(2) receptor protein level affecting the functional pool of receptors. Ablation of the BC1 gene did not result in widespread dysregulation of synaptic transmission, because the sensitivity of cannabinoid CB(1) receptors was intact in the striatum of BC1 knock-out (KO) mice despite D(2) and CB(1) receptors mediated similar electrophysiological actions. Interestingly, the fragile X mental retardation protein FMRP, one of the multiple BC1 partners, is not involved in the BC1 effects on the D(2)-mediated transmission. Because D(2)DR mRNA is apparently equally translated in the BC1-KO and wild-type mice, whereas the protein level is higher in BC1-KO mice, we suggest that BC1 RNA controls D(2)DR indirectly, probably regulating translation of molecules involved in D(2)DR turnover and/or stability.

  1. Stress-induced decrease of uterine blood flow in sheep is mediated by alpha 1-adrenergic receptors.

    Science.gov (United States)

    Dreiling, Michelle; Bischoff, Sabine; Schiffner, Rene; Rupprecht, Sven; Kiehntopf, Michael; Schubert, Harald; Witte, Otto W; Nathanielsz, Peter W; Schwab, Matthias; Rakers, Florian

    2016-09-01

    Prenatal maternal stress can be transferred to the fetus via a catecholamine-dependent decrease of uterine blood flow (UBF). However, it is unclear which group of adrenergic receptors mediates this mechanism of maternal-fetal stress transfer. We hypothesized that in sheep, alpha 1-adrenergic receptors may play a key role in catecholamine mediated UBF decrease, as these receptors are mainly involved in peripheral vasoconstriction and are present in significant number in the uterine vasculature. After chronic instrumentation at 125 ± 1 days of gestation (dGA; term 150 dGA), nine pregnant sheep were exposed at 130 ± 1 dGA to acute isolation stress for one hour without visual, tactile, or auditory contact with their flockmates. UBF, blood pressure (BP), heart rate (HR), stress hormones, and blood gases were determined before and during this isolation challenge. Twenty-four hours later, experiments were repeated during alpha 1-adrenergic receptor blockage induced by a continuous intravenous infusion of urapidil. In both experiments, ewes reacted to isolation with an increase in serum norepinephrine, cortisol, BP, and HR as typical signs of activation of sympatho-adrenal and the hypothalamic-pituitary-adrenal axis. Stress-induced UBF decrease was prevented by alpha 1-adrenergic receptor blockage. We conclude that UBF decrease induced by maternal stress in sheep is mediated by alpha 1-adrenergic receptors. Future studies investigating prevention strategies of impact of prenatal maternal stress on fetal health should consider selective blockage of alpha 1-receptors to interrupt maternal-fetal stress transfer mediated by utero-placental malperfusion.

  2. Prostaglandin E2 potentiation of P2X3 receptor mediated currents in dorsal root ganglion neurons

    Directory of Open Access Journals (Sweden)

    Huang Li-Yen

    2007-08-01

    Full Text Available Abstract Prostaglandin E2 (PGE2 is a well-known inflammatory mediator that enhances the excitability of DRG neurons. Homomeric P2X3 and heteromeric P2X2/3 receptors are abundantly expressed in dorsal root ganglia (DRG neurons and participate in the transmission of nociceptive signals. The interaction between PGE2 and P2X3 receptors has not been well delineated. We studied the actions of PGE2 on ATP-activated currents in dissociated DRG neurons under voltage-clamp conditions. PGE2 had no effects on P2X2/3 receptor-mediated responses, but significantly potentiated fast-inactivating ATP currents mediated by homomeric P2X3 receptors. PGE2 exerted its action by activating EP3 receptors. To study the mechanism underlying the action of PGE2, we found that the adenylyl cyclase activator, forskolin and the membrane-permeable cAMP analogue, 8-Br-cAMP increased ATP currents, mimicking the effect of PGE2. In addition, forskolin occluded the enhancement produced by PGE2. The protein kinase A (PKA inhibitors, H89 and PKA-I blocked the PGE2 effect. In contrast, the PKC inhibitor, bisindolymaleimide (Bis did not change the potentiating action of PGE2. We further showed that PGE2 enhanced α,β-meATP-induced allodynia and hyperalgesia and the enhancement was blocked by H89. These observations suggest that PGE2 binds to EP3 receptors, resulting in the activation of cAMP/PKA signaling pathway and leading to an enhancement of P2X3 homomeric receptor-mediated ATP responses in DRG neurons.

  3. Histamine Regulates the Inflammatory Profile of SOD1-G93A Microglia and the Histaminergic System Is Dysregulated in Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Savina Apolloni

    2017-11-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is a late-onset motor neuron disease where activated glia release pro-inflammatory cytokines that trigger a vicious cycle of neurodegeneration in the absence of resolution of inflammation. Given the well-established role of histamine as a neuron-to-glia alarm signal implicated in brain disorders, the aim of this study was to investigate the expression and regulation of the histaminergic pathway in microglial activation in ALS mouse model and in humans. By examining the contribution of the histaminergic system to ALS, we found that particularly via H1 and H4 receptors, histamine promoted an anti-inflammatory profile in microglia from SOD1-G93A mice by modulating their activation state. A decrease in NF-κB and NADPH oxidase 2 with an increase in arginase 1 and P2Y12 receptor was induced by histamine only in the ALS inflammatory environment, but not in the healthy microglia, together with an increase in IL-6, IL-10, CD163, and CD206 phenotypic markers in SOD1-G93A cells. Moreover, histaminergic H1, H2, H3, and H4 receptors, and histamine metabolizing enzymes histidine decarboxylase, histamine N-methyltransferase, and diamine oxidase were found deregulated in spinal cord, cortex, and hypothalamus of SOD1-G93A mice during disease progression. Finally, by performing a meta-analysis study, we found a modulated expression of histamine-related genes in cortex and spinal cord from sporadic ALS patients. Our findings disclose that histamine acts as anti-inflammatory agent in ALS microglia and suggest a dysregulation of the histaminergic signaling in ALS.

  4. Autocrine EGF receptor activation mediates endothelial cell migration and vascular morphogenesis induced by VEGF under interstitial flow

    International Nuclear Information System (INIS)

    Semino, Carlos E.; Kamm, Roger D.; Lauffenburger, Douglas A.

    2006-01-01

    We show here that autocrine ligand activation of epidermal growth factor (EGF) receptor in combination with interstitial flow is critically involved in the morphogenetic response of endothelial cells to VEGF stimulation. Human umbilical vein endothelial cell (HUVEC) monolayers cultured on a collagen gel and exposed to low interstitial flow in the absence of EGF and VEGF remained viable and mitotic but exhibited little evidence of vascular morphogenesis. Addition of VEGF produced a flow-dependent morphogenetic response within 48 to 72 h, characterized by branched capillary-like structures. The response was substantially abolished by inhibitors related to the autocrine EGF receptor pathway including Galardin, AG1478, PD98059, and an EGF receptor-blocking antibody, indicating that regulation of the morphogenetic process operates via autocrine EGF receptor activation. Moreover, we observed that in our system the EGF receptor was always activated independently of the interstitial flow, and, in addition, the EGF receptor inhibitors used above reduced the phosphorylation state of the receptor, correlating with inhibition of capillary morphogenesis. Finally, 5'bromo-2'-deoxyuridine (BrdU) labeling identified dividing cells at the monolayer but not in the extending capillary-like structures. EGF pathway inhibitors Galardin and AG1478 did not reduce BrdU incorporation in the monolayer, indicating that the EGF-receptor-mediated morphogenetic behavior is mainly due to cell migration rather than proliferation. Based on these results, we propose a two-step model for in vitro capillary morphogenesis in response to VEGF stimulation with interstitial fluid flow: monolayer maintenance by mitotic activity independent of EGF receptors and a migratory response mediated by autocrine EGF receptor activation wherein cells establish capillary-like structures

  5. Dopamine D(1) receptor-mediated control of striatal acetylcholine release by endogenous dopamine.

    Science.gov (United States)

    Acquas, E; Di Chiara, G

    1999-10-27

    acetylcholine release, counteracting the increase of dopamine release and potentiating the decrease in acetylcholine release. These results provide further evidence for the existence of a tonic stimulatory input of endogenous dopamine on striatal acetylcholine transmission mediated by dopamine D(1) receptors.

  6. Orexin/hypocretin receptor 1 signaling mediates Pavlovian cue-food conditioning and extinction.

    Science.gov (United States)

    Keefer, Sara E; Cole, Sindy; Petrovich, Gorica D

    2016-08-01

    Learned food cues can drive feeding in the absence of hunger, and orexin/hypocretin signaling is necessary for this type of overeating. The current study examined whether orexin also mediates cue-food learning during the acquisition and extinction of these associations. In Experiment 1, rats underwent two sessions of Pavlovian appetitive conditioning, consisting of tone-food presentations. Prior to each session, rats received either the orexin 1 receptor antagonist SB-334867 (SB) or vehicle systemically. SB treatment did not affect conditioned responses during the first conditioning session, measured as food cup behavior during the tone and latency to approach the food cup after the tone onset, compared to the vehicle group. During the second conditioning session, SB treatment attenuated learning. All groups that received SB, prior to either the first or second conditioning session, displayed significantly less food cup behavior and had longer latencies to approach the food cup after tone onset compared to the vehicle group. These findings suggest orexin signaling at the 1 receptor mediates the consolidation and recall of cue-food acquisition. In Experiment 2, another group of rats underwent tone-food conditioning sessions (drug free), followed by two extinction sessions under either SB or vehicle treatment. Similar to Experiment 1, SB did not affect conditioned responses during the first session. During the second extinction session, the group that received SB prior to the first extinction session, but vehicle prior to the second, expressed conditioned food cup responses longer after tone offset, when the pellets were previously delivered during conditioning, and maintained shorter latencies to approach the food cup compared to the other groups. The persistence of these conditioned behaviors indicates impairment in extinction consolidation due to SB treatment during the first extinction session. Together, these results demonstrate an important role for orexin

  7. Gambogic acid inhibits multiple myeloma mediated osteoclastogenesis through suppression of chemokine receptor CXCR4 signaling pathways.

    Science.gov (United States)

    Pandey, Manoj K; Kale, Vijay P; Song, Chunhua; Sung, Shen-shu; Sharma, Arun K; Talamo, Giampaolo; Dovat, Sinisa; Amin, Shantu G

    2014-10-01

    Bone disease, characterized by the presence of lytic lesions and osteoporosis is the hallmark of multiple myeloma (MM). Stromal cell-derived factor 1α (SDF-1α) and its receptor, CXC chemokine receptor 4 (CXCR4), has been implicated as a regulator of bone resorption, suggesting that agents that can suppress SDF1α/CXCR4 signaling might inhibit osteoclastogenesis, a process closely linked to bone resorption. We, therefore, investigated whether gambogic acid (GA), a xanthone, could inhibit CXCR4 signaling and suppress osteoclastogenesis induced by MM cells. Through docking studies we predicted that GA directly interacts with CXCR4. This xanthone down-regulates the expression of CXCR4 on MM cells in a dose- and time-dependent manner. The down-regulation of CXCR4 was not due to proteolytic degradation, but rather GA suppresses CXCR4 mRNA expression by inhibiting nuclear factor-kappa B (NF-κB) DNA binding. This was further confirmed by quantitative chromatin immunoprecipitation assay, as GA inhibits p65 binding at the CXCR4 promoter. GA suppressed SDF-1α-induced chemotaxis of MM cells and downstream signaling of CXCR4 by inhibiting phosphorylation of Akt, p38, and Erk1/2 in MM cells. GA abrogated the RANKL-induced differentiation of macrophages to osteoclasts in a dose- and time-dependent manner. In addition, we found that MM cells induced differentiation of macrophages to osteoclasts, and that GA suppressed this process. Importantly, suppression of osteoclastogenesis by GA was mediated through IL-6 inhibition. Overall, our results show that GA is a novel inhibitor of CXCR4 expression and has a strong potential to suppress osteoclastogenesis mediated by MM cells. Published by Elsevier Inc.

  8. The role of receptor-mediated T-cells activation disorders in pulmonary tuberculosis

    Directory of Open Access Journals (Sweden)

    Irina E. Esimova

    2017-01-01

    Full Text Available Aim. To analyze the peculiarities and mechanisms of receptor-mediated T-lymphocytes disorders in different clinical forms of pulmonary tuberculosis.Materials and мethods. The study involved 116 patients with first diagnosed infiltrative and disseminated drug-sensitive and drug-resistant pulmonary tuberculosis. The key stages in receptor-mediated activation of T-lymphocytes, isolated from blood, after their CD3/CD28-induction in vitro with addition of intracellular transport blocker were analyzed. Their immunotyping was carried out with the method of two- and threecolor flow cytofluorometry. The obtained results were statistically analyzed.Results. The breach of extracellular and intracellular stages of T-lymphocytes activation, shown by reduction in total number of CD3- and CD28-positive cells, and CD3+CD28+IL2+, CD3+CD28+IL2–, CD3+NF-kB+, CD3+NFAT2+ lymphocytes, and increase in number of CD3+CTLA4+ cells, was identified with most of their manifestations in disseminated drug-resistant pulmonary tuberculosis. It was shown that the content of CD3+AP-1+ lymphocytes is variable in drug-resistant pulmonary tuberculosis: it increases in the infiltrative form and decreases in the disseminated form.Conclusion. The results showed different mechanisms leading to a deficiency of IL-2-positive lymphocytes and T-lymphocytopenia: from “functional reserve” exhaustion of T-cells in drug-sensitive pulmonary tuberculosis to immunosuppression under the influence of suppressive cytokines (in case of the infiltrative form and inhibitory protein CTLA4 (in case of the disseminated form in drug-resistant pulmonary tuberculosis. 

  9. Orexin/hypocretin receptor 1 signaling mediates Pavlovian cue-food conditioning and extinction

    Science.gov (United States)

    Keefer, Sara E.; Cole, Sindy; Petrovich, Gorica D.

    2016-01-01

    Learned food cues can drive feeding in the absence of hunger, and orexin/hypocretin signaling is necessary for this type of overeating. The current study examined whether orexin also mediates cue-food learning during the acquisition and extinction of these associations. In Experiment 1, rats underwent two sessions of Pavlovian appetitive conditioning, consisting of tone-food presentations. Prior to each session, rats received either the orexin 1 receptor antagonist SB-334867 (SB) or vehicle systemically. SB treatment did not affect conditioned responses during the first conditioning session, measured as food cup behavior during the tone and latency to approach the food cup after the tone onset, compared to the vehicle group. During the second conditioning session, SB treatment attenuated learning. All groups that received SB, prior to either the first or second conditioning session, displayed significantly less food cup behavior and had longer latencies to approach the food cup after tone onset compared to the vehicle group. These findings suggest orexin signaling at the 1 receptor mediates the consolidation and recall of cue-food acquisition. In Experiment 2, another group of rats underwent tone-food conditioning sessions (drug free), followed by two extinction sessions under either SB or vehicle treatment. Similar to Experiment 1, SB did not affect conditioned responses during the first session. During the second extinction session, the group that received SB prior to the first extinction session, but vehicle prior to the second, expressed conditioned food cup responses longer after tone offset, when the pellets were previously delivered during conditioning, and maintained shorter latencies to approach the food cup compared to the other groups. The persistence of these conditioned behaviors indicates impairment in extinction consolidation due to SB treatment during the first extinction session. Together, these results demonstrate an important role for orexin

  10. Neurogenic mediators contribute to local edema induced by Micrurus lemniscatus venom

    Science.gov (United States)

    2017-01-01

    Background/Aims Micrurus is one of the four snake genera of medical importance in Brazil. Coral snakes have a broad geographic distribution from the southern United States to Argentina. Micrurine envenomation is characterized by neurotoxic symptoms leading to dyspnea and death. Moreover, various local manifestations, including edema formation, have been described in patients bitten by different species of Micrurus. Thus, we investigated the ability of Micrurus lemniscatus venom (MLV) to induce local edema. We also explored mechanisms underlying this effect, focusing on participation of neuropeptides and mast cells. Methodology/Principal findings Intraplantar injection of MLV (1–10 μg/paw) in rats caused dose- and time-dependent edema with a peak between 15 min and 1 h after injection. MLV also induced degranulation of peritoneal mast cells (MCs). MC depletion by compound 48/80 markedly reduced MLV-induced edema. Pre-treatment (30 min) of rats with either promethazine a histamine H1 receptor antagonist or methysergide, a nonselective 5-HT receptor antagonist, reduced MLV-induced edema. However, neither thioperamide, a histamine H3/H4 receptor antagonist, nor co-injection of MLV with HOE-140, a BK2 receptor antagonist, altered the response. Depletion of neuropeptides by capsaicin or treatment of animals with NK1- and NK2-receptor antagonists (SR 140333 and SR 48968, respectively) markedly reduced MLV-induced edema. Conclusions/Significance In conclusion, MLV induces paw edema in rats by mechanisms involving activation of mast cells and substance P-releasing sensory C-fibers. Tachykinins NKA and NKB, histamine, and serotonin are major mediators of the MLV-induced edematogenic response. Targeting mast cell- and sensory C-fiber-derived mediators should be considered as potential therapeutic approaches to interrupt development of local edema induced by Micrurus venoms. PMID:29161255

  11. Neurogenic mediators contribute to local edema induced by Micrurus lemniscatus venom.

    Directory of Open Access Journals (Sweden)

    Luciana Lyra Casais-E-Silva

    2017-11-01

    Full Text Available Micrurus is one of the four snake genera of medical importance in Brazil. Coral snakes have a broad geographic distribution from the southern United States to Argentina. Micrurine envenomation is characterized by neurotoxic symptoms leading to dyspnea and death. Moreover, various local manifestations, including edema formation, have been described in patients bitten by different species of Micrurus. Thus, we investigated the ability of Micrurus lemniscatus venom (MLV to induce local edema. We also explored mechanisms underlying this effect, focusing on participation of neuropeptides and mast cells.Intraplantar injection of MLV (1-10 μg/paw in rats caused dose- and time-dependent edema with a peak between 15 min and 1 h after injection. MLV also induced degranulation of peritoneal mast cells (MCs. MC depletion by compound 48/80 markedly reduced MLV-induced edema. Pre-treatment (30 min of rats with either promethazine a histamine H1 receptor antagonist or methysergide, a nonselective 5-HT receptor antagonist, reduced MLV-induced edema. However, neither thioperamide, a histamine H3/H4 receptor antagonist, nor co-injection of MLV with HOE-140, a BK2 receptor antagonist, altered the response. Depletion of neuropeptides by capsaicin or treatment of animals with NK1- and NK2-receptor antagonists (SR 140333 and SR 48968, respectively markedly reduced MLV-induced edema.In conclusion, MLV induces paw edema in rats by mechanisms involving activation of mast cells and substance P-releasing sensory C-fibers. Tachykinins NKA and NKB, histamine, and serotonin are major mediators of the MLV-induced edematogenic response. Targeting mast cell- and sensory C-fiber-derived mediators should be considered as potential therapeutic approaches to interrupt development of local edema induced by Micrurus venoms.

  12. Ultradian hormone stimulation induces glucocorticoid receptor-mediated pulses of gene transcription.

    Science.gov (United States)

    Stavreva, Diana A; Wiench, Malgorzata; John, Sam; Conway-Campbell, Becky L; McKenna, Mervyn A; Pooley, John R; Johnson, Thomas A; Voss, Ty C; Lightman, Stafford L; Hager, Gordon L

    2009-09-01

    Studies on glucocorticoid receptor (GR) action typically assess gene responses by long-term stimulation with synthetic hormones. As corticosteroids are released from adrenal glands in a circadian and high-frequency (ultradian) mode, such treatments may not provide an accurate assessment of physiological hormone action. Here we demonstrate that ultradian hormone stimulation induces cyclic GR-mediated transcriptional regulation, or gene pulsing, both in cultured cells and in animal models. Equilibrium receptor-occupancy of regulatory elements precisely tracks the ligand pulses. Nascent RNA transcripts from GR-regulated genes are released in distinct quanta, demonstrating a profound difference between the transcriptional programs induced by ultradian and constant stimulation. Gene pulsing is driven by rapid GR exchange with response elements and by GR recycling through the chaperone machinery, which promotes GR activation and reactivation in response to the ultradian hormone release, thus coupling promoter activity to the naturally occurring fluctuations in hormone levels. The GR signalling pathway has been optimized for a prompt and timely response to fluctuations in hormone levels, indicating that biologically accurate regulation of gene targets by GR requires an ultradian mode of hormone stimulation.

  13. Astrocytic β2-adrenergic receptors mediate hippocampal long-term memory consolidation

    KAUST Repository

    Gao, Virginia; Suzuki, Akinobu; Magistretti, Pierre J.; Lengacher, Sylvain; Pollonini, Gabriella; Steinman, Michael Q.; Alberini, Cristina M.

    2016-01-01

    Emotionally relevant experiences form strong and long-lasting memories by critically engaging the stress hormone/neurotransmitter noradrenaline, which mediates and modulates the consolidation of these memories. Noradrenaline acts through adrenergic receptors (ARs), of which β2- Adrenergic receptors (βARs) are of particular importance. The differential anatomical and cellular distribution of βAR subtypes in the brain suggests that they play distinct roles in memory processing, although much about their specific contributions and mechanisms of action remains to be understood. Here we show that astrocytic rather than neuronal β2ARs in the hippocampus play a key role in the consolidation of a fear-based contextual memory. These hippocampal β2ARs, but not β1ARs, are coupled to the training-dependent release of lactate from astrocytes, which is necessary for long- Term memory formation and for underlying molecular changes. This key metabolic role of astrocytic β2ARs may represent a novel target mechanism for stress-related psychopathologies and neurodegeneration.

  14. Implications of astrocytes in mediating the protective effects of Selective Estrogen Receptor Modulators upon brain damage

    Directory of Open Access Journals (Sweden)

    George E. Barreto

    2015-04-01

    Full Text Available Selective Estrogen Receptor Modulators (SERMs are steroidal or non-steroidal compounds that are already used in clinical practice for the treatment of breast cancer, osteoporosis and menopausal symptoms. While SERMs actions in the breast, bone, and uterus have been well characterized, their actions in the brain are less well understood. Previous works have demonstrated the beneficial effects of SERMs in different chronic neurodegenerative diseases like Alzheimer, Parkinson’s disease and Multiple sclerosis, as well as acute degeneration as stroke and traumatic brain injury. Moreover, these compounds exhibit similar protective actions as those of estradiol in the Central Nervous System, overt any secondary effect. For these reasons, in the past few years, there has been a growing interest in the neuroprotective effects exerted directly or indirectly by SERMs in the SNC. In this context, astrocytes play an important role in the maintenance of brain metabolism, and antioxidant support to neurons, thus indicating that better protection of astrocytes are an important asset targeting neuronal protection. Moreover, various clinical and experimental studies have reported that astrocytes are essential for the neuroprotective effects of SERMs during neuronal injuries, as these cells express different estrogen receptors in cell membrane, demonstrating that part of SERMs effects upon injury may be mediated by astrocytes. The present work highlights the current evidence on the protective mechanisms of SERMs, such as tamoxifen and raloxifene, in the SNC, and their modulation of astrocytic properties as promising therapeutic targets during brain damage.

  15. The cannabinoid receptor type 2 as mediator of mesenchymal stromal cell immunosuppressive properties.

    Directory of Open Access Journals (Sweden)

    Francesca Rossi

    Full Text Available Mesenchymal stromal cells are non-hematopoietic, multipotent progenitor cells producing cytokines, chemokines, and extracellular matrix proteins that support hematopoietic stem cell survival and engraftment, influence immune effector cell development, maturation, and function, and inhibit alloreactive T-cell responses. The immunosuppressive properties of human mesenchymal stromal cells have attracted much attention from immunologists, stem cell biologists and clinicians. Recently, the presence of the endocannabinoid system in hematopoietic and neural stem cells has been demonstrated. Endocannabinoids, mainly acting through the cannabinoid receptor subtype 2, are able to modulate cytokine release and to act as immunosuppressant when added to activated T lymphocytes. In the present study, we have investigated, through a multidisciplinary approach, the involvement of the endocannabinoids in migration, viability and cytokine release of human mesenchymal stromal cells. We show, for the first time, that cultures of human mesenchymal stromal cells express all of the components of the endocannabinoid system, suggesting a potential role for the cannabinoid CB2 receptor as a mediator of anti-inflammatory properties of human mesenchymal stromal cells, as well as of their survival pathways and their capability to home and migrate towards endocannabinoid sources.

  16. Astrocytic β2-adrenergic receptors mediate hippocampal long-term memory consolidation

    KAUST Repository

    Gao, Virginia

    2016-07-12

    Emotionally relevant experiences form strong and long-lasting memories by critically engaging the stress hormone/neurotransmitter noradrenaline, which mediates and modulates the consolidation of these memories. Noradrenaline acts through adrenergic receptors (ARs), of which β2- Adrenergic receptors (βARs) are of particular importance. The differential anatomical and cellular distribution of βAR subtypes in the brain suggests that they play distinct roles in memory processing, although much about their specific contributions and mechanisms of action remains to be understood. Here we show that astrocytic rather than neuronal β2ARs in the hippocampus play a key role in the consolidation of a fear-based contextual memory. These hippocampal β2ARs, but not β1ARs, are coupled to the training-dependent release of lactate from astrocytes, which is necessary for long- Term memory formation and for underlying molecular changes. This key metabolic role of astrocytic β2ARs may represent a novel target mechanism for stress-related psychopathologies and neurodegeneration.

  17. Surface receptor Toso controls B cell-mediated regulation of T cell immunity.

    Science.gov (United States)

    Yu, Jinbo; Duong, Vu Huy Hoang; Westphal, Katrin; Westphal, Andreas; Suwandi, Abdulhadi; Grassl, Guntram A; Brand, Korbinian; Chan, Andrew C; Föger, Niko; Lee, Kyeong-Hee

    2018-05-01

    The immune system is tightly controlled by regulatory processes that allow for the elimination of invading pathogens, while limiting immunopathological damage to the host. In the present study, we found that conditional deletion of the cell surface receptor Toso on B cells unexpectedly resulted in impaired proinflammatory T cell responses, which led to impaired immune protection in an acute viral infection model and was associated with reduced immunopathological tissue damage in a chronic inflammatory context. Toso exhibited its B cell-inherent immunoregulatory function by negatively controlling the pool of IL-10-competent B1 and B2 B cells, which were characterized by a high degree of self-reactivity and were shown to mediate immunosuppressive activity on inflammatory T cell responses in vivo. Our results indicate that Toso is involved in the differentiation/maintenance of regulatory B cells by fine-tuning B cell receptor activation thresholds. Furthermore, we showed that during influenza A-induced pulmonary inflammation, the application of Toso-specific antibodies selectively induced IL-10-competent B cells at the site of inflammation and resulted in decreased proinflammatory cytokine production by lung T cells. These findings suggest that Toso may serve as a novel therapeutic target to dampen pathogenic T cell responses via the modulation of IL-10-competent regulatory B cells.

  18. Dependence of plasmin-mediated degradation of platelet adhesive receptors on temperature and Ca2+

    International Nuclear Information System (INIS)

    Winters, K.J.; Eisenberg, P.R.; Jaffe, A.S.; Santoro, S.A.

    1990-01-01

    The effects of activation of plasminogen by streptokinase and tissue-type-plasminogen activator on platelet activation and the membrane glycoproteins (GPs) that mediate platelet adhesion and aggregation are not yet fully defined. To clarify effects on platelets during activation of plasminogen in vitro, we used monoclonal antibodies (MoAbs), flow cytometry, and platelets surface-labeled with 125 I to characterize changes in receptors for fibrinogen (GPIIb-IIIa), von Willebrand factor (GPIb), and collagen (GPIa-IIa). Activation of plasminogen in plasma with pharmacologic concentrations of plasminogen activators did not degrade GPIIb-IIIa or GPIb, and caused only a modest decrease in GPIa. In washed platelets GPIIb-IIIa was extensively degraded by plasmin at 37 degrees C in the absence of exogenous Ca 2+ , conditions that destabilize the IIb-IIIa complex. Degradation of GPIb in washed platelets displayed a similar although less-marked dependence on temperature and the absence of Ca 2+ . The binding of activation-specific MoAbs did not increase during activation of plasminogen in plasma. We conclude that during pharmacologic fibrinolysis, reported inhibition of platelet function in plasma is not due to degradation of platelet-adhesive receptors. In addition, platelet activation observed during thrombolytic therapy does not appear to be a direct consequence of plasminogen activation

  19. Histamine release from gut mast cells from patients with inflammatory bowel diseases

    DEFF Research Database (Denmark)

    Nolte, Hendrik; Spjeldnæs, Nikolaj; Kruse, Aksel

    1990-01-01

    Inflammatory mediators from intestinal mast cells may serve as initiators of acute and delayed inflammation. Mast cell histamine release was measured in 19 patients with inflammatory bowel diseases using gut mast cells from enzymatically dispersed endoscopic forceps biopsy specimens...... of macroscopically inflamed and normal tissue. Mast cells and corresponding basophils were challenged with anti-IgE, anti-IgG, subclass anti-IgG4, and formyl-methionyl-leucyl-phenylalanine (FMLP) and results were compared with those from nine patient control subjects. The mast cell count in patients with ulcerative...... colitis was increased compared with that in control subjects and patients with Crohn's disease, and the mast cell count obtained from inflamed tissue was greater than that of normal tissue. The study also shows the heterogeneity of the responsiveness of the histamine releasing cells to various...

  20. Stimulation of dopamine receptor D5 expressed on dendritic cells potentiates Th17-mediated immunity.

    Science.gov (United States)

    Prado, Carolina; Contreras, Francisco; González, Hugo; Díaz, Pablo; Elgueta, Daniela; Barrientos, Magaly; Herrada, Andrés A; Lladser, Álvaro; Bernales, Sebastián; Pacheco, Rodrigo

    2012-04-01

    Dendritic cells (DCs) are responsible for priming T cells and for promoting their differentiation from naive T cells into appropriate effector cells. Emerging evidence suggests that neurotransmitters can modulate T cell-mediated immunity. However, the involvement of specific neurotransmitters or receptors remains poorly understood. In this study, we analyzed the role of dopamine in the regulation of DC function. We found that DCs express dopamine receptors as well as the machinery necessary to synthesize, store, and degrade dopamine. Notably, the expression of D5R decreased upon LPS-induced DC maturation. Deficiency of D5R on the surface of DCs impaired LPS-induced IL-23 and IL-12 production and consequently attenuated the activation and proliferation of Ag-specific CD4(+) T cells. To determine the relevance of D5R expressed on DCs in vivo, we studied the role of this receptor in the modulation of a CD4(+) T cell-driven autoimmunity model. Importantly, D5R-deficient DCs prophylactically transferred into wild-type recipients were able to reduce the severity of experimental autoimmune encephalomyelitis. Furthermore, mice transferred with D5R-deficient DCs displayed a significant reduction in the percentage of Th17 cells infiltrating the CNS without differences in the percentage of Th1 cells compared with animals transferred with wild-type DCs. Our findings demonstrate that by contributing to CD4(+) T cell activation and differentiation to Th17 phenotype, D5R expressed on DCs is able to modulate the development of an autoimmune response in vivo.

  1. Ionotropic glutamate receptors mediate inducible defense in the water flea Daphnia pulex.

    Directory of Open Access Journals (Sweden)

    Hitoshi Miyakawa

    Full Text Available Phenotypic plasticity is the ability held in many organisms to produce different phenotypes with a given genome in response to environmental stimuli, such as temperature, nutrition and various biological interactions. It seems likely that environmental signals induce a variety of mechanistic responses that influence ontogenetic processes. Inducible defenses, in which prey animals alter their morphology, behavior and/or other traits to help protect against direct or latent predation threats, are among the most striking examples of phenotypic plasticity. The freshwater microcrustacean Daphnia pulex forms tooth-like defensive structures, "neckteeth," in response to chemical cues or signals, referred to as "kairomones," in this case released from phantom midge larvae, a predator of D. pulex. To identify factors involved in the reception and/or transmission of a kairomone, we used microarray analysis to identify genes up-regulated following a short period of exposure to the midge kairomone. In addition to identifying differentially expressed genes of unknown function, we also found significant up-regulation of genes encoding ionotropic glutamate receptors, which are known to be involved in neurotransmission in many animal species. Specific antagonists of these receptors strongly inhibit the formation of neckteeth in D. pulex, although agonists did not induce neckteeth by themselves, indicating that ionotropic glutamate receptors are necessary but not sufficient for early steps of neckteeth formation in D. pulex. Moreover, using co-exposure of D. pulex to antagonists and juvenile hormone (JH, which physiologically mediates neckteeth formation, we found evidence suggesting that the inhibitory effect of antagonists is not due to direct inhibition of JH synthesis/secretion. Our findings not only provide a candidate molecule required for the inducible defense response in D. pulex, but also will contribute to the understanding of complex mechanisms

  2. The role of the central histaminergic receptors in the exercise-induced improvements of the spatial learning and memory in rats.

    Science.gov (United States)

    Taati, Majid; Moghaddasi, Mehrnoush; Esmaeili, Masoumeh; Pourkhodadad, Soheila; Nayebzadeh, Hassan

    2014-10-31

    While it is well known that exercise can improve cognitive performance, the underlying mechanisms are not fully understood. There is now evidence that histamine can modulate learning and memory in different types of behavioral tasks. The present study was designed to examine the possible role of central histamine H1 and H2 receptors in forced treadmill running-induced enhancement of learning and memory in rats. For this purpose the animals received intracerebroventricularly chlorpheniramine (H1 receptor blocker) and cimetidine (H2 receptor blocker) before each day of fifteen consecutive days of exercise. Then their learning and memory were tested on the water maze task using a four-trial-per-day for 4 consecutive days. A probe trial was performed after the last training day. Our data showed that cimetidine reversed the exercise-induced improvement in learning and memory in rats; however, this was not the case regarding chlorpheniramine. Our findings indicate that central histamine H2 receptors play an important role in mediating the beneficial effects of forced exercise on learning and memory. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Kinetics of the membrane current mediated by serotonin 5-HT3 receptors in cultured mouse neuroblastoma cells.

    NARCIS (Netherlands)

    Neijt, H.C.; Plomp, J.J.; Vijverberg, H.P.M.

    1989-01-01

    1. Ionic currents mediated by serotonin 5-HT3 receptors were studied in the mouse neuroblastoma cell line N1E-115, using suction pipettes for intracellular perfusion and voltage clamp recording. The dependence of the kinetics of the membrane current on serotonin concentration was investigated. 2. At

  4. The Influence of Receptor-Mediated Interactions on Reaction-Diffusion Mechanisms of Cellular Self-organisation

    Czech Academy of Sciences Publication Activity Database

    Klika, Václav; Baker, R. E.; Headon, D.; Gaffney, E. A.

    2012-01-01

    Roč. 74, č. 4 (2012), s. 935-957 ISSN 0092-8240 Institutional research plan: CEZ:AV0Z20760514 Keywords : reaction-diffusion * receptor-mediated patterning * turing models Subject RIV: BO - Biophysics Impact factor: 2.023, year: 2012 http://www.springerlink.com/content/9713544x6871w4n6/?MUD=MP

  5. Hindbrain GLP-1 receptor mediation of cisplatin-induced anorexia and nausea.

    Science.gov (United States)

    De Jonghe, Bart C; Holland, Ruby A; Olivos, Diana R; Rupprecht, Laura E; Kanoski, Scott E; Hayes, Matthew R

    2016-01-01

    While chemotherapy-induced nausea and vomiting are clinically controlled in the acute (anorexia, nausea, fatigue, and other illness-type behaviors during the delayed phase (>24 h) of chemotherapy are largely uncontrolled. As the hindbrain glucagon-like peptide-1 (GLP-1) system contributes to energy balance and mediates aversive and stressful stimuli, here we examine the hypothesis that hindbrain GLP-1 signaling mediates aspects of chemotherapy-induced nausea and reductions in feeding behavior in rats. Specifically, hindbrain GLP-1 receptor (GLP-1R) blockade, via 4th intracerebroventricular (ICV) exendin-(9-39) injections, attenuates the anorexia, body weight reduction, and pica (nausea-induced ingestion of kaolin clay) elicited by cisplatin chemotherapy during the delayed phase (48 h) of chemotherapy-induced nausea. Additionally, the present data provide evidence that the central GLP-1-producing preproglucagon neurons in the nucleus tractus solitarius (NTS) of the caudal brainstem are activated by cisplatin during the delayed phase of chemotherapy-induced nausea, as cisplatin led to a significant increase in c-Fos immunoreactivity in NTS GLP-1-immunoreactive neurons. These data support a growing body of literature suggesting that the central GLP-1 system may be a potential pharmaceutical target for adjunct anti-emetics used to treat the delayed-phase of nausea and emesis, anorexia, and body weight loss that accompany chemotherapy treatments. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Novel isoforms of the TFIID subunit TAF4 modulate nuclear receptor-mediated transcriptional activity

    International Nuclear Information System (INIS)

    Brunkhorst, Adrian; Neuman, Toomas; Hall, Anita; Arenas, Ernest; Bartfai, Tamas; Hermanson, Ola; Metsis, Madis

    2004-01-01

    The transcription factor TFIID consists of TATA-binding protein (TBP) and TBP-associated factors (TAFs). TAFs are essential for modulation of transcriptional activity but the regulation of TAFs is complex and many important aspects remain unclear. In this study, we have identified and characterized five novel truncated forms of the TFIID subunit TAF4 (TAF II 135). Analysis of the mouse gene structure revealed that all truncations were the results of alternative splicing and resulted in the loss of domains or parts of domains implicated in TAF4 functional interactions. Results from transcriptional assays showed that several of the TAF4 isoforms exerted dominant negative effects on TAF4 activity in nuclear receptor-mediated transcriptional activation. In addition, alternative TAF4 isoforms could be detected in specific cell types. Our results indicate an additional level of complexity in TAF4-mediated regulation of transcription and suggest context-specific roles for these new TAF4 isoforms in transcriptional regulation in vivo

  7. Phagocytosis by macrophages mediated by receptors for denatured proteins - dependence on tyrosine protein kinases

    Directory of Open Access Journals (Sweden)

    M.R. Hespanhol

    2002-03-01

    Full Text Available Previous studies have demonstrated that some components of the leukocyte cell membrane, CR3 (Mac-1, CD11b/CD18 and p150/95, are able to bind to denatured proteins. Thus, it is of interest to know which effector functions of these cells can be triggered by these receptors when they interact with particles or surfaces covered with denatured proteins. In the present study we analyzed their possible role as mediators of phagocytosis of red cells covered with denatured bovine serum albumin (BSA by mouse peritoneal macrophages. We observed that a macrophages are able to recognize (bind to these red cells, b this interaction can be inhibited by denatured BSA in the fluid phase, c there is no phagocytosis of these particles by normal macrophages, d phagocytosis mediated by denatured BSA can be, however, effectively triggered in inflammatory macrophages induced by glycogen or in macrophages activated in vivo with LPS, and e this phagocytic capacity is strongly dependent on the activity of tyrosine protein kinases in its signal transduction pathway, as demonstrated by using three kinds of enzyme inhibitors (genistein, quercetin and herbimycin A.

  8. Chemokine Receptor Ccr1 Drives Neutrophil-Mediated Kidney Immunopathology and Mortality in Invasive Candidiasis

    Science.gov (United States)

    Lionakis, Michail S.; Swamydas, Muthulekha; Wan, Wuzhou; Richard Lee, Chyi-Chia; Cohen, Jeffrey I.; Scheinberg, Phillip; Gao, Ji-Liang; Murphy, Philip M.

    2012-01-01

    Invasive candidiasis is the 4th leading cause of nosocomial bloodstream infection in the US with mortality that exceeds 40% despite administration of antifungal therapy; neutropenia is a major risk factor for poor outcome after invasive candidiasis. In a fatal mouse model of invasive candidiasis that mimics human bloodstream-derived invasive candidiasis, the most highly infected organ is the kidney and neutrophils are the major cellular mediators of host defense; however, factors regulating neutrophil recruitment have not been previously defined. Here we show that mice lacking chemokine receptor Ccr1, which is widely expressed on leukocytes, had selectively impaired accumulation of neutrophils in the kidney limited to the late phase of the time course of the model; surprisingly, this was associated with improved renal function and survival without affecting tissue fungal burden. Consistent with this, neutrophils from wild-type mice in blood and kidney switched from Ccr1lo to Ccr1high at late time-points post-infection, when Ccr1 ligands were produced at high levels in the kidney and were chemotactic for kidney neutrophils ex vivo. Further, when a 1∶1 mixture of Ccr1+/+ and Ccr1−/− donor neutrophils was adoptively transferred intravenously into Candida-infected Ccr1+/+ recipient mice, neutrophil trafficking into the kidney was significantly skewed toward Ccr1+/+ cells. Thus, neutrophil Ccr1 amplifies late renal immunopathology and increases mortality in invasive candidiasis by mediating excessive recruitment of neutrophils from the blood to the target organ. PMID:22916017

  9. Interaction between tumor cell surface receptor RAGE and proteinase 3 mediates prostate cancer metastasis to bone

    Science.gov (United States)

    Kolonin, Mikhail G.; Sergeeva, Anna; Staquicini, Daniela I.; Smith, Tracey L.; Tarleton, Christy A.; Molldrem, Jeffrey J.; Sidman, Richard L.; Marchiò, Serena; Pasqualini, Renata; Arap, Wadih

    2017-01-01

    Human prostate cancer often metastasizes to bone, but the biological basis for such site-specific tropism remains largely unresolved. Recent work led us to hypothesize that this tropism may reflect pathogenic interactions between RAGE, a cell surface receptor expressed on malignant cells in advanced prostate cancer, and proteinase 3 (PR3), a serine protease present in inflammatory neutrophils and hematopoietic cells within the bone marrow microenvironment. In this study, we establish that RAGE-PR3 interaction mediates homing of prostate cancer cells to the bone marrow. PR3 bound to RAGE on the surface of prostate cancer cells in vitro, inducing tumor cell motility through a non-proteolytic signal transduction cascade involving activation and phosphorylation of ERK1/2 and JNK1. In preclinical models of experimental metastasis, ectopic expression of RAGE on human prostate cancer cells was sufficient to promote bone marrow homing within a short time frame. Our findings demonstrate how RAGE-PR3 interactions between human prostate cancer cells and the bone marrow microenvironment mediate bone metastasis during prostate cancer progression, with potential implications for prognosis and therapeutic intervention. PMID:28428279

  10. Time-Dependent Vascular Effects of Endocannabinoids Mediated by Peroxisome Proliferator-Activated Receptor Gamma (PPAR

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    Saoirse E. O'Sullivan

    2009-01-01

    Full Text Available The aim of the present study was to examine whether endocannabinoids cause PPAR-mediated vascular actions. Functional vascular studies were carried out in rat aortae. Anandamide and N-arachidonoyl-dopamine (NADA, but not palmitoylethanolamide, caused significant vasorelaxation over time (2 hours. Vasorelaxation to NADA, but not anandamide, was inhibited by CB1 receptor antagonism (AM251, 1 M, and vasorelaxation to both anandamide and NADA was inhibited by PPAR antagonism (GW9662, 1 M. Pharmacological inhibition of de novo protein synthesis, nitric oxide synthase, and super oxide dismutase abolished the responses to anandamide and NADA. Removal of the endothelium partly inhibited the vasorelaxant responses to anandamide and NADA. Inhibition of fatty acid amide hydrolase (URB597, 1 M inhibited the vasorelaxant response to NADA, but not anandamide. These data indicate that endocannabinoids cause time-dependent, PPAR-mediated vasorelaxation. Activation of PPAR in the vasculature may represent a novel mechanism by which endocannabinoids are involved in vascular regulation.

  11. Chemokine receptor Ccr1 drives neutrophil-mediated kidney immunopathology and mortality in invasive candidiasis.

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    Michail S Lionakis

    Full Text Available Invasive candidiasis is the 4(th leading cause of nosocomial bloodstream infection in the US with mortality that exceeds 40% despite administration of antifungal therapy; neutropenia is a major risk factor for poor outcome after invasive candidiasis. In a fatal mouse model of invasive candidiasis that mimics human bloodstream-derived invasive candidiasis, the most highly infected organ is the kidney and neutrophils are the major cellular mediators of host defense; however, factors regulating neutrophil recruitment have not been previously defined. Here we show that mice lacking chemokine receptor Ccr1, which is widely expressed on leukocytes, had selectively impaired accumulation of neutrophils in the kidney limited to the late phase of the time course of the model; surprisingly, this was associated with improved renal function and survival without affecting tissue fungal burden. Consistent with this, neutrophils from wild-type mice in blood and kidney switched from Ccr1(lo to Ccr1(high at late time-points post-infection, when Ccr1 ligands were produced at high levels in the kidney and were chemotactic for kidney neutrophils ex vivo. Further, when a 1∶1 mixture of Ccr1(+/+ and Ccr1(-/- donor neutrophils was adoptively transferred intravenously into Candida-infected Ccr1(+/+ recipient mice, neutrophil trafficking into the kidney was significantly skewed toward Ccr1(+/+ cells. Thus, neutrophil Ccr1 amplifies late renal immunopathology and increases mortality in invasive candidiasis by mediating excessive recruitment of neutrophils from the blood to the target organ.

  12. Androgen Receptor Deregulation Drives Bromodomain-Mediated Chromatin Alterations in Prostate Cancer

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    Alfonso Urbanucci

    2017-06-01

    Full Text Available Global changes in chromatin accessibility may drive cancer progression by reprogramming transcription factor (TF binding. In addition, histone acetylation readers such as bromodomain-containing protein 4 (BRD4 have been shown to associate with these TFs and contribute to aggressive cancers including prostate cancer (PC. Here, we show that chromatin accessibility defines castration-resistant prostate cancer (CRPC. We show that the deregulation of androgen receptor (AR expression is a driver of chromatin relaxation and that AR/androgen-regulated bromodomain-containing proteins (BRDs mediate this effect. We also report that BRDs are overexpressed in CRPCs and that ATAD2 and BRD2 have prognostic value. Finally, we developed gene stratification signature (BROMO-10 for bromodomain response and PC prognostication, to inform current and future trials with drugs targeting these processes. Our findings provide a compelling rational for combination therapy targeting bromodomains in selected patients in which BRD-mediated TF binding is enhanced or modified as cancer progresses.

  13. Neurotrophin receptor p75NTR mediates Huntington’s disease–associated synaptic and memory dysfunction

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    Brito, Verónica; Giralt, Albert; Enriquez-Barreto, Lilian; Puigdellívol, Mar; Suelves, Nuria; Zamora-Moratalla, Alfonsa; Ballesteros, Jesús J.; Martín, Eduardo D.; Dominguez-Iturza, Nuria; Morales, Miguel; Alberch, Jordi; Ginés, Sílvia

    2014-01-01

    Learning and memory deficits are early clinical manifestations of Huntington’s disease (HD). These cognitive impairments have been mainly associated with frontostriatal HD pathology; however, compelling evidence provided by several HD murine models suggests that the hippocampus may contribute to synaptic deficits and memory dysfunction in HD. The neurotrophin receptor p75NTR negatively regulates spine density, which is associated with learning and memory; therefore, we explored whether disturbed p75NTR function in the hippocampus could contribute to synaptic dysfunction and memory deficits in HD. Here, we determined that levels of p75NTR are markedly increased in the hippocampus of 2 distinct mouse models of HD and in HD patients. Normalization of p75NTR levels in HD mutant mice heterozygous for p75NTR prevented memory and synaptic plasticity deficits and ameliorated dendritic spine abnormalities, likely through normalization of the activity of the GTPase RhoA. Moreover, viral-mediated overexpression of p75NTR in the hippocampus of WT mice reproduced HD learning and memory deficits, while knockdown of p75NTR in the hippocampus of HD mice prevented cognitive decline. Together, these findings provide evidence of hippocampus-associated memory deficits in HD and demonstrate that p75NTR mediates synaptic, learning, and memory dysfunction in HD. PMID:25180603

  14. Effects of environmental estrogenic chemicals on AP1 mediated transcription with estrogen receptors alpha and beta.

    Science.gov (United States)

    Fujimoto, Nariaki; Honda, Hiroaki; Kitamura, Shigeyuki

    2004-01-01

    There has been much discussion concerning endocrine disrupting chemicals suspected of exerting adverse effects in both wildlife and humans. Since the majority of these compounds are estrogenic, a large number of in vitro tests for estrogenic characteristics have been developed for screening purpose. One reliable and widely used method is the reporter gene assay employing estrogen receptors (ERs) and a reporter gene with a cis-acting estrogen responsive element (ERE). Other elements such as AP1 also mediate estrogenic signals and the manner of response could be quite different from that of ERE. Since this has yet to be explored, the ER mediated AP1 activity in response to a series of environmental estrogens was investigated in comparison with ERE findings. All the compounds exhibited estrogenic properties with ERE-luc and their AP1 responses were quite similar. These was one exception, however, p,p'-DDT (1,1,1,-trichloro-2,2-bis(p-chlorophenyl)ethane) did not exert any AP1-luc activity, while it appeared to be estrogenic at 10(-7) to 10(-5)M with the ERE action. None of the compounds demonstrated ER beta:AP1 activity. These data suggest that significant differences can occur in responses through the two estrogen pathways depending on environmental chemicals.

  15. Platelet-activating factor receptor agonists mediate xeroderma pigmentosum A photosensitivity.

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    Yao, Yongxue; Harrison, Kathleen A; Al-Hassani, Mohammed; Murphy, Robert C; Rezania, Samin; Konger, Raymond L; Travers, Jeffrey B

    2012-03-16

    To date, oxidized glycerophosphocholines (Ox-GPCs) with platelet-activating factor (PAF) activity produced non-enzymatically have not been definitively demonstrated to mediate any known disease processes. Here we provide evidence that these Ox-GPCs play a pivotal role in the photosensitivity associated with the deficiency of the DNA repair protein xeroderma pigmentosum type A (XPA). It should be noted that XPA-deficient cells are known to have decreased antioxidant defenses. These studies demonstrate that treatment of human XPA-deficient fibroblasts with the pro-oxidative stressor ultraviolet B (UVB) radiation resulted in increased reactive oxygen species and PAF receptor (PAF-R) agonistic activity in comparison with gene-corrected cells. The UVB irradiation-generated PAF-R agonists were inhibited by antioxidants. UVB irradiation of XPA-deficient (Xpa-/-) mice also resulted in increased PAF-R agonistic activity and skin inflammation in comparison with control mice. The increased UVB irradiation-mediated skin inflammation and TNF-α production in Xpa-/- mice were blocked by systemic antioxidants and by PAF-R antagonists. Structural characterization of PAF-R-stimulating activity in UVB-irradiated XPA-deficient fibroblasts using mass spectrometry revealed increased levels of sn-2 short-chain Ox-GPCs along with native PAF. These studies support a critical role for PAF-R agonistic Ox-GPCs in the pathophysiology of XPA photosensitivity.

  16. Sphingosine 1-phosphate receptor 5 mediates the immune quiescence of the human brain endothelial barrier

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    van Doorn Ruben

    2012-06-01

    Full Text Available Abstract Background The sphingosine 1-phosphate (S1P receptor modulator FTY720P (Gilenya® potently reduces relapse rate and lesion activity in the neuroinflammatory disorder multiple sclerosis. Although most of its efficacy has been shown to be related to immunosuppression through the induction of lymphopenia, it has been suggested that a number of its beneficial effects are related to altered endothelial and blood–brain barrier (BBB functionality. However, to date it remains unknown whether brain endothelial S1P receptors are involved in the maintenance of the function of the BBB thereby mediating immune quiescence of the brain. Here we demonstrate that the brain endothelial receptor S1P5 largely contributes to the maintenance of brain endothelial barrier function. Methods We analyzed the expression of S1P5 in human post-mortem tissues using immunohistochemistry. The function of S1P5 at the BBB was assessed in cultured human brain endothelial cells (ECs using agonists and lentivirus-mediated knockdown of S1P5. Subsequent analyses of different aspects of the brain EC barrier included the formation of a tight barrier, the expression of BBB proteins and markers of inflammation and monocyte transmigration. Results We show that activation of S1P5 on cultured human brain ECs by a selective agonist elicits enhanced barrier integrity and reduced transendothelial migration of monocytes in vitro. These results were corroborated by genetically silencing S1P5 in brain ECs. Interestingly, functional studies with these cells revealed that S1P5 strongly contributes to brain EC barrier function and underlies the expression of specific BBB endothelial characteristics such as tight junctions and permeability. In addition, S1P5 maintains the immunoquiescent state of brain ECs with low expression levels of leukocyte adhesion molecules and inflammatory chemokines and cytokines through lowering the activation of the transcription factor NFκB. Conclusion Our

  17. Suppression of TLR4-mediated inflammatory response by macrophage class A scavenger receptor (CD204)

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    Ohnishi, Koji; Komohara, Yoshihiro; Fujiwara, Yukio; Takemura, Kenichi [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan); Lei, XiaoFeng [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan); Department of Biochemistry, Showa University School of Medicine, Tokyo (Japan); Nakagawa, Takenobu [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan); Sakashita, Naomi [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan); Department of Human Pathology, Institute of Health Biosciences, The University of Tokushima, Tokushima (Japan); Takeya, Motohiro, E-mail: takeya@kumamoto-u.ac.jp [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan)

    2011-08-05

    Highlights: {yields} We focused on the interaction between SR-A and TLR4 signaling in this study. {yields} SR-A deletion promoted NF{kappa}B activation in macrophages in septic model mouse. {yields} SR-A suppresses both MyD88-dependent and -independent TLR4 signaling in vitro. {yields} SR-A clears LPS binding to TLR4 which resulting in the suppression of TLR4 signals. -- Abstract: The class A scavenger receptor (SR-A, CD204), one of the principal receptors expressed on macrophages, has been found to regulate inflammatory response and attenuate septic endotoxemia. However, the detailed mechanism of this process has not yet been well characterized. To clarify the regulative mechanisms of lipopolysaccharide (LPS)-induced macrophage activation by SR-A, we evaluated the activation of Toll-like receptor 4 (TLR4)-mediated signaling molecules in SR-A-deficient (SR-A{sup -/-}) macrophages. In a septic shock model, the blood levels of tumor necrosis factor (TNF)-{alpha}, interleukin (IL)-6 and interferon (IFN)-{beta} were significantly increased in SR-A{sup -/-} mice compared to wild-type mice, and elevated nuclear factor kappa B (NF{kappa}B) activation was detected in SR-A{sup -/-} macrophages. SR-A deletion increased the production of pro-inflammatory cytokines, and the phosphorylation of mitogen-activated protein kinase (MAPK) and NF{kappa}B in vitro. SR-A deletion also promoted the nuclear translocation of NF{kappa}B and IFN regulatory factor (IRF)-3. In addition, a competitive binding assay with acetylated low-density lipoprotein, an SR-A-specific ligand, and anti-SR-A antibody induced significant activation of TLR4-mediated signaling molecules in wild-type macrophages but not in SR-A{sup -/-} macrophages. These results suggest that SR-A suppresses the macrophage activation by inhibiting the binding of LPS to TLR4 in a competitive manner and it plays a pivotal role in the regulation of the LPS-induced inflammatory response.

  18. Estrogen-mediated inactivation of FOXO3a by the G protein-coupled estrogen receptor GPER

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