Sample records for cd1d-dependent antagonist inhibits

  1. CD1d-dependent NKT cells play a protective role in acute and chronic arthritis models by ameliorating antigen-specific Th1 responses

    DEFF Research Database (Denmark)

    Teige, Anna; Bockermann, Robert; Hasan, Maruf


    A protective and anti-inflammatory role for CD1d-dependent NKT cells (NKTs) has been reported in experimental and human autoimmune diseases. However, their role in arthritis has been unclear, with conflicting reports of CD1d-dependent NKTs acting both as regulatory and disease-promoting cells...

  2. CD1d-dependent expansion of NKT follicular helper cells in vivo and in vitro is a product of cellular proliferation and differentiation. (United States)

    Rampuria, Pragya; Lang, Mark L


    NKT follicular helper cells (NKTfh cells) are a recently discovered functional subset of CD1d-restricted NKT cells. Given the potential for NKTfh cells to promote specific antibody responses and germinal center reactions, there is much interest in determining the conditions under which NKTfh cells proliferate and/or differentiate in vivo and in vitro. We confirm that NKTfh cells expressing the canonical semi-invariant Vα14 TCR were CXCR5(+)/ICOS(+)/PD-1(+)/Bcl6(+) and increased in number following administration of the CD1d-binding glycolipid α-galactosylceramide (α-GC) to C57Bl/6 mice. We show that the α-GC-stimulated increase in NKTfh cells was CD1d-dependent since the effect was diminished by reduced CD1d expression. In vivo and in vitro treatment with α-GC, singly or in combination with IL-2, showed that NKTfh cells increased in number to a greater extent than total NKT cells, but proliferation was near-identical in both populations. Acquisition of the NKTfh phenotype from an adoptively transferred PD-1-depleted cell population was also evident, showing that peripheral NKT cells differentiated into NKTfh cells. Therefore, the α-GC-stimulated, CD1d-dependent increase in peripheral NKTfh cells is a result of cellular proliferation and differentiation. These findings advance our understanding of the immune response following immunization with CD1d-binding glycolipids.

  3. Inhibition of tryptase release from human colon mast cells by histamine receptor antagonists. (United States)

    He, Shao-Heng; Xie, Hua; Fu, Yi-Ling


    The main objective of this study was to investigate the ability of histamine receptor antagonists to modulate tryptase release from human colon mast cells induced by histamine. Enzymatically dispersed cells from human colon were challenged with histamine in the absence or presence of the histamine receptor antagonists, and the tryptase release was determined. It was found that histamine induced tryptase release from colon mast cells was inhibited by up to approximately 61.5% and 24% by the H1 histamine receptor antagonist terfenadine and the H2 histamine receptor antagonist cimetidine, respectively, when histamine and its antagonists were added to cells at the same time. The H3 histamine receptor antagonist clobenpropit had no effect on histamine induced tryptase release from colon mast cells at all concentrations tested. Preincubation of terfenadine, cimetidine or clobenpropit with cells for 20 minutes before challenging with histamine did not enhance the ability of these antihistamines to inhibit histamine induced tryptase release. Apart from terfenadine at 100 microg/ml, the antagonists themselves did not stimulate tryptase release from colon mast cells following both 15 minutes and 35 minutes incubation periods. It was concluded that H1 and H2 histamine receptor antagonists were able to inhibit histamine induced tryptase release from colon mast cells. This not only added some new data to our hypothesis of self-amplification mechanisms of mast cell degranulation, but also suggested that combining these two types of antihistamine drugs could be useful for the treatment of inflammatory bowel disease (IBD).

  4. Angiotensin II AT1 receptor antagonists inhibit platelet adhesion and aggregation by nitric oxide release. (United States)

    Kalinowski, Leszek; Matys, Tomasz; Chabielska, Ewa; Buczko, Włodzimierz; Malinski, Tadeusz


    This study investigated the process of nitric oxide (NO) release from platelets after stimulation with different angiotensin II type 1 (AT1)-receptor antagonists and its effect on platelet adhesion and aggregation. Angiotensin II AT1-receptor antagonist-stimulated NO release in platelets was compared with that in human umbilical vein endothelial cells by using a highly sensitive porphyrinic microsensor. In vitro and ex vivo effects of angiotensin II AT1-receptor antagonists on platelet adhesion to collagen and thromboxane A2 analog U46619-induced aggregation were evaluated. Losartan, EXP3174, and valsartan alone caused NO release from platelets and endothelial cells in a dose-dependent manner in the range of 0.01 to 100 micro mol/L, which was attenuated by NO synthase inhibitor N(G)-nitro-L-arginine methyl ester. The angiotensin II AT1-receptor antagonists had more than 70% greater potency in NO release in platelets than in endothelial cells. The degree of inhibition of platelet adhesion (collagen-stimulated) and aggregation (U46619-stimulated) elicited by losartan, EXP3174, and valsartan, either in vitro or ex vivo, closely correlated with the NO levels produced by each of these drugs alone. The inhibiting effects of angiotensin II AT1-receptor antagonists on collagen-stimulated adhesion and U46619-stimulated aggregation of platelets were significantly reduced by pretreatment with N(G)-nitro-L-arginine methyl ester. Neither the AT2 receptor antagonist PD123319, the cyclooxygenase synthase inhibitor indomethacin, nor the selective thromboxane A2/prostaglandin H2 receptor antagonist SQ29,548 had any effect on angiotensin II AT1-receptor antagonist-stimulated NO release in platelets and endothelial cells. The presented studies clearly indicate a crucial role of NO in the arterial antithrombotic effects of angiotensin II AT1-receptor antagonists.

  5. A RNA antagonist of hypoxia-inducible factor-1alpha, EZN-2968, inhibits tumor cell growth

    DEFF Research Database (Denmark)

    Greenberger, Lee M; Horak, Ivan D; Filpula, David;


    pathways, is associated with poor prognosis in many types of cancer. Therefore, down-regulation of HIF-1alpha protein by RNA antagonists may control cancer growth. EZN-2968 is a RNA antagonist composed of third-generation oligonucleotide, locked nucleic acid, technology that specifically binds and inhibits...... the expression of HIF-1alpha mRNA. In vitro, in human prostate (15PC3, PC3, and DU145) and glioblastoma (U373) cells, EZN-2968 induced a potent, selective, and durable antagonism of HIF-1 mRNA and protein expression (IC(50), 1-5 nmol/L) under normoxic and hypoxic conditions associated with inhibition of tumor...

  6. Novel antagonists of alcohol inhibition of l1-mediated cell adhesion: multiple mechanisms of action. (United States)

    Wilkemeyer, Michael F; Menkari, Carrie E; Charness, Michael E


    1-Octanol antagonizes ethanol inhibition of L1-mediated cell adhesion and prevents ethanol teratogenesis in mouse whole embryo culture. Herein, we identify a new series of alcohol antagonists and study their mechanism of action. Cell aggregation assays were carried out in ethanol-sensitive, human L1-transfected NIH/3T3 cells in the absence and presence of 100 mM ethanol or 2 mM 1-butanol and candidate antagonists. Antagonist potency for 1-alcohols increased progressively over 5 log orders from 1-pentanol (C5) to 1-dodecanol (C12). Antagonist potency declined from 1-dodecanol (C12) to 1-tridecanol (C13), and 1-tetradecanol (C14) and 1-pentadecanol (C15) were inactive. The presence and position of a double bond in the 1-butanol molecule determined whether a compound was a full agonist (1-butanol), a mixed agonist-antagonist (2-buten-1-ol), or an antagonist (3-buten-1-ol). Increasing the concentration of agonist (1-butanol or ethanol) overcame the antagonism of 3-buten-1-ol, benzyl alcohol, cyclopentanol, and 3-pentanol, but not that of 4-methyl-1-pentanol, 2-methyl-2-pentanol, 1-pentanol, 2-pentanol, 1-octanol, and 2,6-di-isopropylphenol (propofol), suggesting that the mechanisms of antagonism may differ between these groups of compounds. These findings suggest that selective straight, branched, and cyclic alcohols may act at multiple, discrete sites to antagonize the actions of ethanol and 1-butanol on L1-mediated cell-cell adhesion.

  7. Effect of dopamine and serotonin receptor antagonists on fencamfamine-induced abolition of latent inhibition. (United States)

    de Aguiar, Cilene Rejane Ramos Alves; de Aguiar, Marlison José Lima; DeLucia, Roberto; Silva, Maria Teresa Araujo


    The purpose of this investigation was to verify the role of dopamine and serotonin receptors in the effect of fencamfamine (FCF) on latent inhibition. FCF is a psychomotor stimulant with an indirect dopaminergic action. Latent inhibition is a model of attention. Latent inhibition is blocked by dopaminergic agents and facilitated by dopamine receptor agonists. FCF has been shown to abolish latent inhibition. The serotonergic system may also participate in the neurochemical mediation of latent inhibition. The selective dopamine D(1) receptor antagonist SCH 23390 (7-chloro-3-methyl-1-phenyl-1,2,4,5-tetrahydro-3-benzazepin-8-ol), D(2) receptor antagonists pimozide (PIM) and methoclopramide (METH), and serotonin 5-HT(2A/C) receptor antagonist ritanserin (RIT) were used in the present study. Latent inhibition was evaluated using a conditioned emotional response procedure. Male Wistar rats that were water-restricted were subjected to a three-phase procedure: preexposure to a tone, tone-shock conditioning, and a test of the effect of the tone on licking frequency. All of the drugs were administered before the preexposure and conditioning phases. The results showed that FCF abolished latent inhibition, and this effect was clearly antagonized by PIM and METH and moderately attenuated by SCH 23390. At the doses used in the present study, RIT pretreatment did not affect latent inhibition and did not eliminate the effect of FCF, suggesting that the FCF-induced abolition of latent inhibition is not mediated by serotonin 5-HT(2A/C) receptors. These results suggest that the effect of FCF on latent inhibition is predominantly related to dopamine D(2) receptors and that dopamine D(2) receptors participate in attention processes.

  8. CysLT(1)R antagonists inhibit tumor growth in a xenograft model of colon cancer. (United States)

    Savari, Sayeh; Liu, Minghui; Zhang, Yuan; Sime, Wondossen; Sjölander, Anita


    The expression of the inflammatory G-protein coupled receptor CysLT1R has been shown to be upregulated in colon cancer patients and associated with poor prognosis. The present study investigated the correlation between CysLT1R and colon cancer development in vivo using CysLT1R antagonists (ZM198,615 or Montelukast) and the nude mouse xenograft model. Two drug administration regimens were established. The first regimen was established to investigate the importance of CysLT1R in tumor initiation. Nude mice were inoculated with 50 µM CysLT1R antagonist-pretreated HCT-116 colon cancer cells and received continued treatment (5 mg/kg/day, intraperitoneally). The second regimen aimed to address the role of CysLT1R in tumor progression. Nude mice were inoculated with non-pretreated HCT-116 cells and did not receive CysLT1R antagonist treatment until recordable tumor appearance. Both regimens resulted in significantly reduced tumor size, attributed to changes in proliferation and apoptosis as determined by reduced Ki-67 levels and increased levels of p21(WAF/Cip1) (Pcolon cancer cell line HCT-116 and CysLT1R antagonists. In addition to significant reductions in cell proliferation, adhesion and colony formation, we observed induction of cell cycle arrest and apoptosis in a dose-dependent manner. The ability of Montelukast to inhibit growth of human colon cancer xenograft was further validated by using two additional colon cancer cell lines, SW-480 and HT-29. Our results demonstrate that CysLT1R antagonists inhibit growth of colon cancer xenografts primarily by reducing proliferation and inducing apoptosis of the tumor cells.

  9. A novel synthetic smoothened antagonist transiently inhibits pancreatic adenocarcinoma xenografts in a mouse model.

    Directory of Open Access Journals (Sweden)

    Martin F Strand

    Full Text Available BACKGROUND: Hedgehog (Hh signaling is over-activated in several solid tumors where it plays a central role in cell growth, stroma recruitment and tumor progression. In the Hh signaling pathway, the Smoothened (SMO receptor comprises a primary drug target with experimental small molecule SMO antagonists currently being evaluated in clinical trials. PRINCIPAL FINDINGS: Using Shh-Light II (Shh-L2 and alkaline phosphatase (AP based screening formats on a "focused diversity" library we identified a novel small molecule inhibitor of the Hh pathway, MS-0022 (2-bromo-N-(4-(8-methylimidazo[1,2-a]pyridin-2-ylphenylbenzamide. MS-0022 showed effective Hh signaling pathway inhibition at the level of SMO in the low nM range, and Hh pathway inhibition downstream of Suppressor of fused (SUFU in the low µM range. MS-0022 reduced growth in the tumor cell lines PANC-1, SUIT-2, PC-3 and FEMX in vitro. MS-0022 treatment led to a transient delay of tumor growth that correlated with a reduction of stromal Gli1 levels in SUIT-2 xenografts in vivo. SIGNIFICANCE: We document the in vitro and in vivo efficacy and bioavailability of a novel small molecule SMO antagonist, MS-0022. Although MS-0022 primarily interferes with Hh signaling at the level of SMO, it also has a downstream inhibitory effect and leads to a stronger reduction of growth in several tumor cell lines when compared to related SMO antagonists.

  10. Retinoid antagonists inhibit normal patterning during limb regeneration in the axolotl, Ambystoma mexicanum. (United States)

    Del Rincón, Sonia V; Scadding, Steven R


    Retinoic acid (RA) has been detected in the regenerating limb of the axolotl, and exogenous RA can proximalize, posteriorize, and ventralize blastemal cells. Thus, RA may be an endogenous regulatory factor during limb regeneration. We have investigated whether endogenous retinoids are essential for patterning during axolotl (Ambystoma mexicanum) limb regeneration by using retinoid antagonists that bind to specific RAR (retinoic acid receptor) or RXR (retinoid X receptor) retinoid receptor subtypes. Retinoid antagonists (Ro41-5253, Ro61-8431, LE135, and LE540) were administered to regenerating limbs using implanted silastin blocks loaded with each antagonist. The skeletal pattern of regenerated limbs treated with Ro41-5253 or Ro61-8431 differed only slightly from control limbs. Treatment with LE135 inhibited limb regeneration, while treatment with LE540 allowed relatively normal limb regeneration. When LE135 and LE540 were implanted together, regeneration was not completely inhibited and a hand-like process regenerated. These results demonstrate that interfering with retinoid receptors can modify pattern in the regenerating limb indicating that endogenous retinoids are important during patterning of the regenerating limb.

  11. PPARγ antagonist attenuates mouse immune-mediated bone marrow failure by inhibition of T cell function. (United States)

    Sato, Kazuya; Feng, Xingmin; Chen, Jichun; Li, Jungang; Muranski, Pawel; Desierto, Marie J; Keyvanfar, Keyvan; Malide, Daniela; Kajigaya, Sachiko; Young, Neal S


    Acquired aplastic anemia is an immune-mediated disease, in which T cells target hematopoietic cells; at presentation, the bone marrow is replaced by fat. It was reported that bone marrow adipocytes were negative regulators of hematopoietic microenvironment. To examine the role of adipocytes in bone marrow failure, we investigated peroxisomal proliferator-activated receptor gamma, a key transcription factor in adipogenesis, utilizing an antagonist of this factor called bisphenol-A-diglycidyl-ether. While bisphenol-A-diglycidyl-ether inhibited adipogenesis as expected, it also suppressed T cell infiltration of bone marrow, reduced plasma inflammatory cytokines, decreased expression of multiple inflammasome genes, and ameliorated marrow failure. In vitro, bisphenol-A-diglycidyl-ether suppressed activation and proliferation, and reduced phospholipase C gamma 1 and nuclear factor of activated T-cells 1 expression, as well as inhibiting calcium flux in T cells. The in vivo effect of bisphenol-A-diglycidyl-ether on T cells was confirmed in a second immune-mediated bone marrow failure model, using different strains and non-major histocompatibility antigen mismatched: bisphenol-A-diglycidyl-ether ameliorated marrow failure by inhibition of T cell infiltration of bone marrow. Our data indicate that peroxisomal proliferator-activated receptor gamma antagonists may attenuate murine immune-mediated bone marrow failure, at least in part, by suppression of T cell activation, which might hold implications in the application of peroxisomal proliferator-activated receptor gamma antagonists in immune-mediated pathophysiologies, both in the laboratory and in the clinic. Genetically "fatless" mice developed bone marrow failure with accumulation of marrow adipocytes in our model, even in the absence of body fat, suggesting different mechanisms of systematic and marrow adipogenesis and physiologic versus pathophysiologic fat accumulation.

  12. Interfering with Resistance to Smoothened Antagonists by Inhibition of the PI3K Pathway in Medulloblastoma (United States)

    Buonamici, Silvia; Williams, Juliet; Morrissey, Michael; Wang, Anlai; Guo, Ribo; Vattay, Anthony; Hsiao, Kathy; Yuan, Jing; Green, John; Ospina, Beatrice; Yu, Qunyan; Ostrom, Lance; Fordjour, Paul; Anderson, Dustin L.; Monahan, John E.; Kelleher, Joseph F.; Peukert, Stefan; Pan, Shifeng; Wu, Xu; Maira, Sauveur-Michel; Garcia-Echeverria, Carlos; Briggs, Kimberly J.; Watkins, D. Neil; Yao, Yung-mae; Lengauer, Christoph; Warmuth, Markus; Sellers, William R.; Dorsch, Marion


    Mutations in Hedgehog (Hh) pathway genes, leading to constitutive activation of Smoothened (Smo), occur in medulloblastoma. Antagonists of Smo induce tumor regression in mouse models of medulloblastoma and hold great promise for treating this disease. However, acquired resistance has emerged as a challenge to targeted therapeutics and may limit their anti-cancer efficacy. Here, we describe novel mechanisms of acquired resistance to Smo antagonists in medulloblastoma. NVP-LDE225, a potent and selective Smo antagonist, inhibits Hh signaling and induces tumor regressions in allograft models of medulloblastoma that are driven by mutations of Patched (Ptch), a tumor suppressor in the Hh pathway. However, evidence of resistance was observed during the course of treatment. Molecular analysis of resistant tumors revealed distinct resistance mechanisms. Chromosomal amplification of Gli2, a downstream effector of Hh signaling, or more rarely point mutations in Smo led to reactivated Hh signaling and restored tumor growth. Unexpectedly, analysis of pathway gene-expression signatures selectively deregulated in resistant tumors identified increased phosphoinositide 3-kinase (PI3K) signaling as another potential resistance mechanism. Probing the functional relevance of increased PI3K signaling, we demonstrated that the combination of NVP-LDE225 with the PI3K class I inhibitor NVP-BKM120 or the dual PI3K/mTOR inhibitor NVP-BEZ235 markedly delayed the development of resistance. Our findings have important clinical implications for future treatment strategies in medulloblastoma. PMID:20881279

  13. Characterization of mechanisms involved in presynaptic inhibition of sympathetic pressor effects induced by some 5-HT1 receptor antagonists. (United States)

    Fernández, M M; Calama, E; Morán, A; Martín, M L; San Román, L


    1. In a previous study, we showed that the presynaptic inhibitory action of 5-hydroxytryptamine receptor agonists on sympathetic pressor effects obtained in the pithed rats were mainly mediated by activation of 5-HT1A and 5-HT1D receptor subtypes. At the time, we observed that some 5-HT1 receptors antagonists - WAY 100,635 and NAN-190 (both 5-HT1A receptor antagonists), methiothepin (a 5-HT1,2,5,6,7 receptor antagonist) and spiperone (a 5-HT1,2 receptor antagonist) - reduced per se the pressor effects obtained by electrical stimulation. The aim of the present work was to investigate the mechanism participating in this inhibitory effect. 2. The inhibition induced by WAY 100,635 (1000 microg kg-1, i.v.) was blocked after i.v. treatment with idazoxan, an alpha2-adrenoceptor antagonist (300 and 1000 microg kg-1) and was not modified after i.v. treatment with propranolol, a beta-adrenoceptor antagonist (1000 microg kg-1) and sulpiride, a D2 receptor antagonist (1000 microg kg-1). The inhibition induced by spiperone (500 microg kg-1 i.v.) was significantly blocked by sulpiride (1000 microg kg-1) and was not modified by idazoxan or propranolol. 3. Sulpiride (1000 microg kg-1) partially blocked the inhibition induced by methiothepin (50 microg kg-1 i.v.). Only pretreatment with idazoxan (300 microg kg-1) modified the inhibition induced by NAN-190 (100 microg kg-1 i.v.), such inhibition increasing after intravenous administration of idazoxan. 4. All the antagonists used in our experiments failed to inhibit the pressor responses elicited by i.v. noradrenaline administration. 5. The above results suggest that the inhibitory effects of these 5-HT1 receptor antagonists are presynaptic in nature, but not related to the blockade of 5-HT1 receptors subtypes. The simultaneous activation or inhibition of other receptor systems could explain the inhibition produced by each 5-HT1 receptor antagonist studied.

  14. Inhibition of osteoporosis by the αvβ3 integrin antagonist of rhodostomin variants. (United States)

    Lin, Tzu-Hung; Yang, Rong-Sen; Tu, Huang-Ju; Liou, Houng-Chi; Lin, Yen-Ming; Chuang, Woie-Jer; Fu, Wen-Mei


    Integrins are heterodimeric cell surface receptors that mediate cell-cell and cell-matrix interaction. The vitronectin and osteopontin receptor αvβ3 integrin has increased expression levels and is implicated in the adhesion, activation, and migration of osteoclasts on the bone surface as well as osteoclast polarization. αvβ3 integrin plays an important role in osteoclast differentiation and resorption. In addition, Arg-Gly-Asp (RGD)-containing peptides, small molecular inhibitors, and antibodies to αvβ3 integrin have been shown to inhibit bone resorption in vitro and in vivo. Here we examined the effects of a disintegrin HSA-ARLDDL a genetically modified mutant of rhodostomin conjugated with human serum albumin, which is highly selective of αvβ3, on RANKL-induced osteoclastogenesis and ovariectomy (OVX)-induced osteoporosis. In RANKL-induced osteoclastogenesis, HSA-ARLDDL significantly inhibited osteoclast formation, and IC50 was at nM range. Post-treatment HSA-ARLDDL also inhibits osteoclast formation. Furthermore, weekly administration of HSA-ARLDDL significantly inhibits the increase in serum bone resorption marker levels and decrease in cancellous bone loss in tibia and femur induced by OVX. On the other hand, HSA-ARLDDL did not affect the differentiation and calcium deposition of osteoblasts. These results indicate that the highly selective and long-acting αvβ3 integrin antagonists could be developed as effective drugs for postmenopausal osteoporosis.

  15. Urinary responses to acute moxonidine are inhibited by natriuretic peptide receptor antagonist. (United States)

    El-Ayoubi, Rouwayda; Menaouar, Ahmed; Gutkowska, Jolanta; Mukaddam-Daher, Suhayla


    We have previously shown that acute intravenous injections of moxonidine and clonidine increase plasma atrial natriuretic peptide (ANP), a vasodilator, diuretic and natriuretic hormone. We hypothesized that moxonidine stimulates the release of ANP, which would act on its renal receptors to cause diuresis and natriuresis, and these effects may be altered in hypertension. Moxonidine (0, 10, 50, 100 or 150 microg in 300 microl saline) and clonidine (0, 1, 5 or 10 microg in 300 microl saline) injected intravenously in conscious normally hydrated normotensive Sprague-Dawley rats (SD, approximately 200 g) and 12-14-week-old Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) dose-dependently stimulated diuresis, natriuresis, kaliuresis and cGMP excretion, with these effects being more pronounced during the first hour post-injection. The actions of 5 microg clonidine and 50 microg moxonidine were inhibited by yohimbine, an alpha2-adrenoceptor antagonist, and efaroxan, an imidazoline I1-receptor antagonist. Moxonidine (100 microg) stimulated (P<0.01) diuresis in SHR (0.21+/-0.04 vs 1.16+/-0.06 ml h(-1) 100 g(-1)), SD (0.42+/-0.06 vs 1.56+/-0.19 ml h(-1) 100 g(-1)) and WKY (0.12+/-0.04 vs 1.44+/-0.21 ml h(-1) 100 g(-1)). Moxonidine-stimulated urine output was lower in SHR than in SD and WKY. Moxonidine-stimulated sodium and potassium excretions were lower in SHR than in SD, but not WKY, demonstrating an influence of strain but not of pressure. Pretreatment with the natriuretic peptide antagonist anantin (5 or 10 microg) resulted in dose-dependent inhibition of moxonidine-stimulated urinary actions. Anantin (10 microg) inhibited (P<0.01) urine output to 0.38+/-0.06, 0.12+/-0.01, and 0.16+/-0.04 ml h(-1) 100 g(-1) in SD, WKY, and SHR, respectively. Moxonidine increased (P<0.01) plasma ANP in SD (417+/-58 vs 1021+/-112 pg ml(-1)) and WKY (309+/-59 vs 1433+/-187 pg ml(-1)), and in SHR (853+/-96 vs 1879+/-229 pg ml(-1)). These results demonstrate that natriuretic

  16. The pheromone production of female Plodia interpunctella is inhibited by tyraminergic antagonists. (United States)

    Hirashima, Akinori; Kimizu, Megumi; Shigeta, Yoko; Matsugu, Sachiko; Eiraku, Tomohiko; Kuwano, Eiichi; Eto, Morifusa


    Several compounds were found to suppress the calling behavior and in vitro pheromone biosynthesis of the Indian meal moth, Plodia interpunctella. The compounds were screened by means of a calling-behavior bioassay with female P. interpunctella. Five derivatives with activities in the nanomolar range were identified, in order of decreasing pheromonostatic activity: 4-hydroxybenzaldehyde semicarbazone (42) > 5-(4-methoxyphenyl)-1,3-oxazole (38) > 5-[4-(tert-butyl)phenyl]-1,3-oxazole (40) > 5-(3-methoxyphenyl)-1,3-oxazole (35) > 5-(4-cyanophenyl)-1,3-oxazole (36). These compounds also showed in vitro inhibitory activity in intracellular de novo pheromone biosynthesis, as determined with isolated pheromone-gland preparations that incorporated [1-(14)C]sodium acetate in the presence of the so-called pheromone-biosynthesis-activating neuropeptide (PBAN). The non-additive effect of the inhibitor with antagonist (yohimbine) for the tyramine (TA) receptor suggests that it could be a tyraminergic antagonist. Three-dimensional (3D) computer models were built from a set of compounds. Among the common-featured models generated by the program Catalyst/HipHop, aromatic-ring (AR) and H-bond-acceptor-lipophilic (HBAl) features were considered to be essential for inhibitory activity in the calling behavior and in vitro pheromone biosynthesis. Active compounds, including yohimbine, mapped well onto all the AR and HBAl features of the hypothesis. Less-active compounds were shown to be unable to achieve an energetically favorable conformation, consistent with our 3D common-feature pharmacophore models. The present hypothesis demonstrates that calling behavior and PBAN-stimulated incorporation of radioactivity are inhibited by tyraminergic antagonists.

  17. Synthetic peptide with inhibin-like activity preferentially inhibits follitropin secretion in comparison with lutropin-releasing hormone antagonists

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    Sairam, M.R.; Ramasharma, K.; Li, C.H.


    Biological activity of a synthetic peptide with inhibin-like activity under in vitro and in vivo conditions was compared with three highly potent synthetic lutropin-releasing hormone antagonists. Unlike the synthetic lutropin-releasing hormone antagonists, which effectively inhibited both lutropin and follitropin secretion from the pituitary, the inhibin-like peptide showed a preferential effect by inhibiting follitropin release both in vitro and in vivo. Thus, small peptides such as inhibin-like peptide with a sequence unrelated to lutropin-releasing hormone may provide a basis for design of selective inhibitors of gonadotropin release. FSH and LH were measured by radioimmunoassay.

  18. Ciproxifan, a histamine H3 receptor antagonist, reversibly inhibits monoamine oxidase A and B. (United States)

    Hagenow, S; Stasiak, A; Ramsay, R R; Stark, H


    Ciproxifan is a well-investigated histamine H3 receptor (H3R) inverse agonist/antagonist, showing an exclusively high species-specific affinity at rodent compared to human H3R. It is well studied as reference compound for H3R in rodent models for neurological diseases connected with neurotransmitter dysregulation, e.g. attention deficit hyperactivity disorder or Alzheimer's disease. In a screening for potential monoamine oxidase A and B inhibition ciproxifan showed efficacy on both enzyme isoforms. Further characterization of ciproxifan revealed IC50 values in a micromolar concentration range for human and rat monoamine oxidases with slight preference for monoamine oxidase B in both species. The inhibition by ciproxifan was reversible for both human isoforms. Regarding inhibitory potency of ciproxifan on rat brain MAO, these findings should be considered, when using high doses in rat models for neurological diseases. As the H3R and monoamine oxidases are all capable of affecting neurotransmitter modulation in brain, we consider dual targeting ligands as interesting approach for treatment of neurological disorders. Since ciproxifan shows only moderate activity at human targets, further investigations in animals are not of primary interest. On the other hand, it may serve as starting point for the development of dual targeting ligands.

  19. A novel thromboxane receptor antagonist, nstpbp5185, inhibits platelet aggregation and thrombus formation in animal models. (United States)

    Huang, Shiu-Wen; Kuo, Heng-Lan; Hsu, Ming-Tsung; Tseng, Yufeng Jane; Lin, Shu-Wha; Kuo, Sheng-Chu; Peng, Hui-Chin; Lien, Jin-Cherng; Huang, Tur-Fu


    A novel benzimidazole derivative, nstpbp5185, was discovered through in vitro and in vivo evaluations for antiplatelet activity. Thromaboxane receptor (TP) is important in vascular physiology, haemostasis and pathophysiological thrombosis. Nstpbp5185 concentration-dependently inhibited human platelet aggregation caused by collagen, arachidonic acid and U46619. Nstpbp5185 caused a right-shift of the concentration-response curve of U46619 and competitively inhibited the binding of 3H-SQ-29548 to TP receptor expressed on HEK-293 cells, with an IC50 of 0.1 µM, indicating that nstpbp5185 is a TP antagonist. In murine thrombosis models, nstpbp5185 significantly prolonged the latent period in triggering platelet plug formation in mesenteric and FeCl3-induced thrombi formation, and increased the survival rate in pulmonary embolism model with less bleeding than aspirin. This study suggests nstpbp5185, an orally selective anti-thrombotic agent, acting through blockade of TXA2 receptor, may be efficacious for prevention or treatment of pathologic thrombosis.

  20. Growth inhibition of Penicillium digitatum by antagonistic microorganisms isolated from various parts of orange tree

    Directory of Open Access Journals (Sweden)

    Wasu Pathom-aree


    Full Text Available Penicillium digitatum (Pers.:Fr Sacc. is the major cause of green mold disease in orange trees grown for orange production industry in Thailand. In this study, antagonistic microorganisms were isolated from various parts of healthy orange trees. A total of 121 microbial isolates were recovered from which 15 isolates showed inhibitory effect against P. digitatum by spot test technique. The inhibitory effect of these 15 isolates was also tested by agar disc diffusion method using culture filtrate from nutrient broth. It was found that isolate W1L1, D1L2 and W1L9 gave the best inhibition with a clear zone of 21, 15 and 14 mm in diameter, respectively. The effect of culture filtrate on spore germination was also investigated. The result showed that isolate W1L1 gave the highest inhibition after 8 hours of incubation with the lowest germination rate of 2.4%. Morphological and biochemical characterizations revealed that these isolates were members of the genus Bacillus and identified as B. pumilus.

  1. Inhibition of Human Immunodeficiency Virus Replication by a Dual CCR5/CXCR4 Antagonist (United States)

    Princen, Katrien; Hatse, Sigrid; Vermeire, Kurt; Aquaro, Stefano; De Clercq, Erik; Gerlach, Lars-Ole; Rosenkilde, Mette; Schwartz, Thue W.; Skerlj, Renato; Bridger, Gary; Schols, Dominique


    Here we report that the N-pyridinylmethyl cyclam analog AMD3451 has antiviral activity against a wide variety of R5, R5/X4, and X4 strains of human immunodeficiency virus type 1 (HIV-1) and HIV-2 (50% inhibitory concentration [IC50] ranging from 1.2 to 26.5 μM) in various T-cell lines, CCR5- or CXCR4-transfected cells, peripheral blood mononuclear cells (PBMCs), and monocytes/macrophages. AMD3451 also inhibited R5, R5/X4, and X4 HIV-1 primary clinical isolates in PBMCs (IC50, 1.8 to 7.3 μM). A PCR-based viral entry assay revealed that AMD3451 blocks R5 and X4 HIV-1 infection at the virus entry stage. AMD3451 dose-dependently inhibited the intracellular Ca2+ signaling induced by the CXCR4 ligand CXCL12 in T-lymphocytic cells and in CXCR4-transfected cells, as well as the Ca2+ flux induced by the CCR5 ligands CCL5, CCL3, and CCL4 in CCR5-transfected cells. The compound did not interfere with chemokine-induced Ca2+ signaling through CCR1, CCR2, CCR3, CCR4, CCR6, CCR9, or CXCR3 and did not induce intracellular Ca2+ signaling by itself at concentrations up to 400 μM. In freshly isolated monocytes, AMD3451 inhibited the Ca2+ flux induced by CXCL12 and CCL4 but not that induced by CCL2, CCL3, CCL5, and CCL7. The CXCL12- and CCL3-induced chemotaxis was also dose-dependently inhibited by AMD3451. Furthermore, AMD3451 inhibited CXCL12- and CCL3L1-induced endocytosis in CXCR4- and CCR5-transfected cells. AMD3451, in contrast to the specific CXCR4 antagonist AMD3100, did not inhibit but enhanced the binding of several anti-CXCR4 monoclonal antibodies (such as clone 12G5) at the cell surface, pointing to a different interaction with CXCR4. AMD3451 is the first low-molecular-weight anti-HIV agent with selective HIV coreceptor, CCR5 and CXCR4, interaction. PMID:15542651

  2. Inhibition of establishment of primary and micrometastatic tumors by a urokinase plasminogen activator receptor antagonist. (United States)

    Ignar, D M; Andrews, J L; Witherspoon, S M; Leray, J D; Clay, W C; Kilpatrick, K; Onori, J; Kost, T; Emerson, D L


    Tumor establishment and metastasis are dependent on extracellular matrix proteolysis, tumor cell migration, and angiogenesis. Urokinase plasminogen activator (uPA) and its receptor are essential mediators of these processes. The purpose of this study was to investigate the effect of a recombinant human uPAR antagonist on growth, establishment, and metastasis of tumors derived from human cancer cell lines. A noncatalytic recombinant protein, consisting of amino acids 1-137 of human uPA and the CH2 and CH3 regions of mouse IgG1 (uPA-IgG), was expressed, purified, and shown to bind specifically to human uPAR and to saturate the surface of human tumor cells which express uPAR. Daily i.p. administration of uPA-IgG to nude mice extended latencies of unstaged tumors derived from Lox melanoma and SW48 colon carcinoma cells by 7.7 and 5.5 days, respectively. uPA-IgG treatment did not affect the growth of Lox or KB tumors staged to 200 mg before antagonist treatment commenced. The effect of uPA-IgG on the establishment of micrometastases was assessed in SCID mice. KB head/neck tumor cells were injected in the tail vein and allowed to seed for 48 h before initiation of daily i.p. injections of uPA-IgG for 24 days. The number of lung colonies ranged between 5 and 30% of vehicle-treated mice in two separate experiments. Furthermore, a single 800 microg dose of uPA-IgG administered 1 h prior to tail vein injection of KB cells reduced lung colony formation to just 3.5% of vehicle-treated SCID mice. These data demonstrate that antagonism of uPAR arrested metastasis and inhibited the establishment of primary tumors and micrometastases. Thus, small molecule uPAR antagonists may serve as useful adjuvant agents in combination with existing cancer chemotherapy.

  3. Bosentan, a mixed endothelin receptor antagonist, inhibits superoxide anion-induced pain and inflammation in mice. (United States)

    Serafim, Karla G G; Navarro, Suelen A; Zarpelon, Ana C; Pinho-Ribeiro, Felipe A; Fattori, Victor; Cunha, Thiago M; Alves-Filho, Jose C; Cunha, Fernando Q; Casagrande, Rubia; Verri, Waldiceu A


    Bosentan is a mixed endothelin receptor antagonist widely used to treat patients with pulmonary arterial hypertension, and the emerging literature suggests bosentan as a potent anti-inflammatory drug. Superoxide anion is produced in large amounts during inflammation, stimulates cytokine production, and thus contributes to inflammation and pain. However, it remains to be determined whether endothelin contributes to the inflammatory response triggered by the superoxide anion. The present study investigated the effects of bosentan in a mouse model of inflammation and pain induced by potassium superoxide, a superoxide anion donor. Male Swiss mice were treated with bosentan (10-100 mg/kg) by oral gavage, 1 h before potassium superoxide injection, and the inflammatory response was evaluated locally and at spinal cord (L4-L6) levels. Bosentan (100 mg/kg) inhibited superoxide anion-induced mechanical and thermal hyperalgesia, overt pain-like behavior (abdominal writhings, paw flinching, and licking), paw edema, myeloperoxidase activity (neutrophil marker) in the paw skin, and leukocyte recruitment in the peritoneal cavity. Bosentan also inhibited superoxide anion-induced interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) production, while it enhanced IL-10 production in the paw skin and spinal cord. Bosentan inhibited the reduction of antioxidant capacity (reduced glutathione, ferric reducing antioxidant power, and ABTS radical scavenging ability) induced by the superoxide anion. Finally, we demonstrated that intraplantar injection of potassium superoxide induces the mRNA expression of prepro-endothelin-1 in the paw skin and spinal cord. In conclusion, our results demonstrated that superoxide anion-induced inflammation, pain, cytokine production, and oxidative stress depend on endothelin; therefore, these responses are amenable to bosentan treatment.

  4. An optimized B lymphocyte stimulator (BLyS) antagonist peptide inhibits the interaction of BLyS with BCMA. (United States)

    Tian, Yu; Zhu, Yan-Feng; Wu, Zhen; Feng, Jian-Nan; Li, Yan; Shen, Bei-Fen; Sun, Jian


    B lymphocyte stimulator (BLyS) antagonists are new therapeutic reagents for treating the autoimmune diseases. Peptibodies can inhibit the bioactivity of BLyS, the same as other BLyS antagonists: decoyed BLyS receptors and anti-BLyS antibodies. In this study, a new optimized BLyS antagonist peptide was designed according to our previous work by the computer-aided homology modeling. Competitive ELISA showed that the peptide at 100 μg/ml could inhibit 54 % of the BCMA-Fc binding to BLyS. To maintain its stability and spatial conformation, the peptide was fused to human IgG1 Fc to form a peptide-Fc fusion protein-a novel peptibody by gene engineering. ELISA indicated that the peptibody could bind with BLyS in dosage-dependent manner as BCMA-Fc did. This study highlights the possibility of designing and optimizing BLyS antagonist peptides with high biopotency by the computer-aided design. Thus, these peptides could neutralize BLyS activity and be potential antagonists to treat autoimmune diseases related with BLyS overexpression.

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

    LENUS (Irish Health Repository)

    Dooley, Ruth


    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.

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

    LENUS (Irish Health Repository)

    Dooley, Ruth


    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.

  7. Effect of the NMDA antagonist MK-801 on latent inhibition of fear conditioning. (United States)

    Traverso, Luis M; Ruiz, Gabriel; De la Casa, Luis G


    N-methyl-D-aspartate (NMDA) receptors seem to play a central role in learning and memory processes involved in Latent Inhibition (LI). In fact, MK-801, a non-competitive NMDA receptor antagonist, has proved its effectiveness as a drug for attenuating LI when administered before or after stimulus preexposure and conditioning stages. This paper presents three experiments designed to analyze the effect of MK-801 on LI when the drug is administered before (Experiment 1A) or after (Experiment 1B) preexposure and conditioning stages with a conditioned emotional response procedure. Additionally, we analyze the effect of the drug when it was administered before preexposure, before conditioning or before both phases (Experiment 2). The results show that the effect of the drug varied as a function of the dose (with only the highest dose being effective), the moment of administration (with only the drug administered before the experimental treatments being effective), and the phase of procedure (reducing LI when the drug was administered only at preexposure, and disrupting fear conditioning when administered at conditioning). These differences may be due to several factors ranging from the role played by NMDA receptors in the processing of stimuli of different sensorial modalities to the molecular processes triggered by drug administration.

  8. Oral Administration of a Retinoic Acid Receptor Antagonist Reversibly Inhibits Spermatogenesis in Mice


    Chung, Sanny S. W.; Wang, Xiangyuan; Roberts, Shelby S.; Stephen M Griffey; Reczek, Peter R.; Wolgemuth, Debra J.


    Meeting men's contraceptive needs, orally administered retinoic acid receptor antagonists represent new lead molecules in developing non-hormonal, reversible male contraceptives without adverse side effects.

  9. IL-21 Receptor Antagonist Inhibits Differentiation of B Cells toward Plasmablasts upon Alloantigen Stimulation (United States)

    de Leur, Kitty; Dor, Frank J. M. F.; Dieterich, Marjolein; van der Laan, Luc J. W.; Hendriks, Rudi W.; Baan, Carla C.


    Interaction between T follicular helper (Tfh) cells and B cells is complex and involves various pathways, including the production of IL-21 by the Tfh cells. Secretion of IL-21 results in B cell differentiation toward immunoglobulin-producing plasmablasts. In patients after kidney transplantation, the formation of alloantibodies produced by donor antigen-activated B cells are a major cause of organ failure. In this allogeneic response, the role of IL-21-producing Tfh cells that regulate B cell differentiation is unknown. Here, we tested, in an alloantigen-driven setting, whether Tfh cell help signals control B cell differentiation with its dependency on IL-21. Pre-transplantation patient PBMCs were sorted into pure CD4posCXCR5pos Tfh cells and CD19posCD27pos memory B cells and stimulated with donor antigen in the presence or absence of an IL-21 receptor (IL-21R) antagonist (αIL-21R). Donor antigen stimulation initiated expression of the activation markers inducible co-stimulator (ICOS) and programmed death 1 (PD-1) on Tfh cells and a shift toward a mixed Tfh2 and Tfh17 phenotype. The memory B cells underwent class switch recombination and differentiated toward IgM- and IgG-producing plasmablasts. In the presence of αIL-21R, a dose-dependent inhibition of STAT3 phosphorylation was measured in both T and B cells. Blockade of the IL-21R did not have an effect on PD-1 and ICOS expression on Tfh cells but significantly inhibited B cell differentiation. The proportion of plasmablasts decreased by 78% in the presence of αIL-21R. Moreover, secreted IgM and IgG2 levels were significantly lower in the presence of αIL-21R. In conclusion, our results demonstrate that IL-21 produced by alloantigen-activated Tfh cells controls B cell differentiation toward antibody producing plasmablasts. The IL-21R might, therefore, be a useful target in organ transplantation to prevent antigen-driven immune responses leading to graft failure. PMID:28373876

  10. Inhibition of a slow synaptic response by a metabotropic glutamate receptor antagonist in hippocampal CA3 pyramidal cells. (United States)

    Gerber, U; Lüthi, A; Gähwiler, B H


    The effects of a novel antagonist of metabotropic glutamate receptors were investigated in CA3 pyramidal cells in hippocampal slice cultures of the rat. Earlier experiments showed that selective activation of metabotropic glutamate receptors with low concentrations of an agonist, 1S, 3R-1-amino-cyclopentane-1,3-dicarboxylic acid (ACPD), induced an inward current associated with a decrease in membrane conductance and inhibition of the slow calcium-dependent potassium current. These responses were strongly and reversibly reduced by the antagonist, (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG, 0.5-1 mM). In the presence of antagonists of ionotropic glutamate receptors, stimulation of the afferent mossy fibres evoked postsynaptic responses in CA3 pyramidal cells which paralleled those observed with exogenously applied metabotropic glutamate receptor agonists, i.e. a slow inward current and a reduction of calcium-dependent potassium current. Both responses were greatly reduced by bath-applied MCPG (1 mM). These results show that MCPG acts as an effective antagonist at metabotropic glutamate receptors coupled to potassium conductances in the hippocampus. Furthermore, they confirm that glutamate release from presynaptic terminals can modulate postsynaptic properties by activation of metabotropic glutamate receptors.

  11. 5-HT2B Receptor Antagonists Inhibit Fibrosis and Protect from RV Heart Failure


    Wiebke Janssen; Yves Schymura; Tatyana Novoyatleva; Baktybek Kojonazarov; Mario Boehm; Astrid Wietelmann; Himal Luitel; Kirsten Murmann; Damian Richard Krompiec; Aleksandra Tretyn; Soni Savai Pullamsetti; Norbert Weissmann; Werner Seeger; Hossein Ardeschir Ghofrani; Ralph Theo Schermuly


    Objective. The serotonin (5-HT) pathway was shown to play a role in pulmonary hypertension (PH), but its functions in right ventricular failure (RVF) remain poorly understood. The aim of the current study was to investigate the effects of Terguride (5-HT2A and 2B receptor antagonist) or SB204741 (5-HT2B receptor antagonist) on right heart function and structure upon pulmonary artery banding (PAB) in mice. Methods. Seven days after PAB, mice were treated for 14 days with Terguride (0.2 mg/kg b...

  12. Bicyclams, selective antagonists of the human chemokine receptor CXCR4, potently inhibit feline immunodeficiency virus replication

    NARCIS (Netherlands)

    Horzinek, M.C.; Egberink, H.F.; Clercq, E. de; Vliet, A.L.W. van; Balzarini, J.; Bridger, G.J.; Henson, G.; Schols, D.


    Bicyclams are low-molecular-weight anti-human immunodeficiency virus (HIV) agents that have been shown to act as potent and selective CXC chemokine receptor 4 (CXCR4) antagonists. Here, we demonstrate that bicyclams are potent inhibitors of feline immunodeficiency virus (FIV) replication when evalua

  13. Identification and Characterization of a Novel IL-4 Receptor α Chain (IL-4Rα Antagonist to Inhibit IL-4 Signalling

    Directory of Open Access Journals (Sweden)

    Nayyar Ahmed


    Full Text Available Background/Aims: In recent times, allergy has become a financial, physical and psychological burden to the society as a whole. In allergic cascades, cytokine IL-4 binds to IL-4 receptor (IL-4R, consequently producing allergen-specific IgE antibodies by B cells. In addition, among other functions, IL-4 is also responsible for B and T cell proliferation and differentiation. Hence, characterization of novel antagonists that inhibit IL-4 signalling forms the overall aim of this study. Methods: Phage display was used to screen a random 12-mer synthetic peptide library with a human IL-4Rα to identify peptide candidates. Once identified, the peptides were commercially synthesized and used for in vitro immunoassays. Results: We have successfully used phage display to identify M13 phage clones that demonstrated specific binding to IL-4Rα. The peptide N1 was synthesized for use in ELISA, demonstrating significant binding to IL-4Rα and inhibiting interaction with cytokine IL-4. Furthermore, the peptide was tested in a transfected HEK-Blue IL-4 reporter cell line model, which produces alkaline phosphatase (AP. QUANTI-Blue, a substrate, breaks down in the presence of AP producing a blue coloration. Using this colorimetric analysis, >50% inhibition of IL-4 signalling was achieved. Conclusion: We have successfully identified and characterised a synthetic peptide antagonist against IL-4Rα, which effectively inhibits IL-4 interaction with the IL-4Rα in vitro. Since IL-4 interaction with IL-4Rα is a common pathway for many allergies, a prophylactic treatment can be devised by inhibiting this interaction for future treatment of allergies.

  14. The antidepressant 5-HT2A receptor antagonists pizotifen and cyproheptadine inhibit serotonin-enhanced platelet function.

    Directory of Open Access Journals (Sweden)

    Olivia A Lin

    Full Text Available There is considerable interest in defining new agents or targets for antithrombotic purposes. The 5-HT2A receptor is a G-protein coupled receptor (GPCR expressed on many cell types, and a known therapeutic target for many disease states. This serotonin receptor is also known to regulate platelet function. Thus, in our FDA-approved drug repurposing efforts, we investigated the antiplatelet activity of cyproheptadine and pizotifen, two antidepressant 5-HT2A Receptor antagonists. Our results revealed that cyproheptadine and pizotifen reversed serotonin-enhanced ADP-induced platelet aggregation in vitro and ex vivo. And the inhibitory effects of these two agents were found to be similar to that of EMD 281014, a 5-HT2A Receptor antagonist under development. In separate experiments, our studies revealed that these 5-HT2A receptor antagonists have the capacity to reduce serotonin-enhanced ADP-induced elevation in intracellular calcium levels and tyrosine phosphorylation. Using flow cytometry, we also observed that cyproheptadine, pizotifen, and EMD 281014 inhibited serotonin-enhanced ADP-induced phosphatidylserine (PS exposure, P-selectin expression, and glycoprotein IIb-IIIa activation. Furthermore, using a carotid artery thrombosis model, these agents prolonged the time for thrombotic occlusion in mice in vivo. Finally, the tail-bleeding time was investigated to assess the effect of cyproheptadine and pizotifen on hemostasis. Our findings indicated prolonged bleeding time in both cyproheptadine- and pizotifen-treated mice. Notably, the increases in occlusion and bleeding times associated with these two agents were comparable to that of EMD 281014, and to clopidogrel, a commonly used antiplatelet drug, again, in a fashion comparable to clopidogrel and EMD 281014. Collectively, our data indicate that the antidepressant 5-HT2A antagonists, cyproheptadine and pizotifen do exert antiplatelet and thromboprotective effects, but similar to clopidogrel and

  15. Drosophila BRUCE inhibits apoptosis through non-lysine ubiquitination of the IAP-antagonist REAPER


    Domingues, C.; Ryoo, H D


    Active caspases execute apoptosis to eliminate superfluous or harmful cells in animals. In Drosophila, living cells prevent uncontrolled caspase activation through an inhibitor of apoptosis protein (IAP) family member, dIAP1, and apoptosis is preceded by the expression of IAP-antagonists, such as Reaper, Hid and Grim. Strong genetic modifiers of this pathway include another IAP family gene encoding an E2 ubiquitin conjugating enzyme domain, dBruce. Although the genetic effects of dBruce mutan...

  16. TRPA1 and TRPV1 Antagonists Do Not Inhibit Human Acidosis-Induced Pain. (United States)

    Schwarz, Matthias G; Namer, Barbara; Reeh, Peter W; Fischer, Michael J M


    Acidosis occurs in a variety of pathophysiological and painful conditions where it is thought to excite or contribute to excitation of nociceptive neurons. Despite potential clinical relevance the principal receptor for sensing acidosis is unclear, but several receptors have been proposed. We investigated the contribution of the acid-sensing ion channels, transient receptor potential vanilloid type 1 (TRPV1) and transient receptor potential ankyrin type 1 (TRPA1) to peripheral pain signaling. We first established a human pain model using intraepidermal injection of the TRPA1 agonist carvacrol. This resulted in concentration-dependent pain sensations, which were reduced by experimental TRPA1 antagonist A-967079. Capsaicin-induced pain was reduced by the TRPV1 inhibitor BCTC. Amiloride was used to block acid-sensing ion channels. Testing these antagonists in a double-blind and randomized experiment, we probed the contribution of the respective channels to experimental acidosis-induced pain in 15 healthy human subjects. A continuous intraepidermal injection of pH 4.3 was used to counter the buffering capacity of tissue and generate a prolonged painful stimulation. In this model, addition of A-967079, BCTC or amiloride did not reduce the reported pain. In conclusion, target-validated antagonists, applied locally in human skin, have excluded the main hypothesized targets and the mechanism of the human acidosis-induced pain remains unclear.

  17. Inhibition of the development of morphine tolerance by a potent dual mu-delta-opioid antagonist, H-Dmt-Tic-Lys-NH-CH2-Ph. (United States)

    Jinsmaa, Yunden; Marczak, Ewa D; Balboni, Gianfranco; Salvadori, Severo; Lazarus, Lawrence H


    Three analogues of the dual mu-/delta-antagonist, H-Dmt-Tic-R-NH-CH2-Ph (R = 1, Lys-Z; 2, Lys-Ac; 3, Lys) were examined in vivo: 1 and 2 exhibited weak bioactivity, while 3 injected intracerebroventricularly was a potent dual antagonist for morphine- and deltorphin C-induced antinociception comparable to naltrindole (delta-antagonist), but 93% as effective as naloxone (nonspecific opioid receptor antagonist) and 4% as active as CTOP, a mu antagonist. Subcutaneous or oral administration of 3 antagonized morphine-induced antinociception indicating passage across epithelial and blood-brain barriers. Mice pretreated with 3 before morphine did not develop morphine tolerance indicative of a potential clinical role to inhibit development of drug tolerance.

  18. Endocannabinoid CB1 antagonists inhibit hepatitis C virus production, providing a novel class of antiviral host-targeting agents. (United States)

    Shahidi, Mahsa; Tay, Enoch S E; Read, Scott A; Ramezani-Moghadam, Mehdi; Chayama, Kazuaki; George, Jacob; Douglas, Mark W


    Direct-acting antivirals have significantly improved treatment outcomes in chronic hepatitis C (CHC), but side effects, drug resistance and cost mean that better treatments are still needed. Lipid metabolism is closely linked with hepatitis C virus (HCV) replication, and endocannabinoids are major regulators of lipid homeostasis. The cannabinoid 1 (CB1) receptor mediates these effects in the liver. We have previously shown upregulation of CB1 receptors in the livers of patients with CHC, and in a HCV cell-culture model. Here, we investigated whether CB1 blockade inhibited HCV replication. The antiviral effect of a CB1 antagonist, N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251), was examined in HCV strain JFH1 cell-culture and subgenomic replicon models. The effects on the expression of genes involved in lipid metabolism were also measured. CB1 short hairpin RNA (shRNA) was used to confirm that the effects were specific for the cannabinoid receptor. Treatment with AM251 strongly inhibited HCV RNA (~70 %), viral protein (~80 %), the production of new virus particles (~70 %) and virus infectivity (~90 %). As expected, AM251 reduced the expression of pro-lipogenic genes (SREBP-1c, FASN, SCD1 and ACC1) and stimulated genes promoting lipid oxidation (CPT1 and PPARα). This effect was mediated by AMP-activated protein kinase (AMPK). Stable CB1 knockdown of cells infected with HCV showed reduced levels of HCV RNA compared with controls. Thus, reduced CB1 signalling inhibits HCV replication using either pharmacological inhibitors or CB1 shRNA. This may be due, at least in part, to reduced lipogenesis, mediated by AMPK activation. We suggest that CB1 antagonists may represent an entirely new class of drug with activity against HCV.

  19. A peptide antagonist of ErbB receptors, Inherbin3, induces neurite outgrowth from rat cerebellar granule neurons through ErbB1 inhibition

    DEFF Research Database (Denmark)

    Xu, Ruodan; Pankratova, Stanislava; Christiansen, Søren Hofman


    ErbB receptors not only function in cancer, but are also key developmental regulators in the nervous system. We previously identified an ErbB1 peptide antagonist, Inherbin3, that is capable of inhibiting tumor growth in vitro and in vivo. In this study, we found that inhibition of ErbB1 kinase...... outgrowth in rat cerebellar granule neurons, indicating that this effect mainly was due to inhibition of ErbB1 activation....

  20. Nanoparticle-linked antagonist for leptin signaling inhibition in breast cancer (United States)

    Harmon, Tia; Harbuzariu, Adriana; Lanier, Viola; Lipsey, Crystal C; Kirlin, Ward; Yang, Lily; Gonzalez-Perez, Ruben R


    AIM To develop a leptin peptide receptor antagonist linked to nanoparticles and determine its effect on viability of breast cancer cells. METHODS The leptin antagonist, LPrA2, was coupled via EDAC [1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide] to iron oxide nanoparticles (IONP-LPrA2) to increase its efficacy. IONP-LPrA2 conjugation was confirmed by Western blot and nanoparticle tracking analysis. Human triple negative breast cancer (TNBC) MDA-MB-231, HCC1806 and estrogen receptor positive (ER+) MCF-7 cells were analyzed for the expression of the leptin receptor, Ob-R. The effects of leptin and antagonist on levels of leptin-induced STAT3 phosphorylation and cyclin D1, cell cycle progression, cell proliferation, and tumorsphere formation in breast cancer cells were determined. Doses of the chemotherapeutics [cisplatin (Cis), cyclophosphamide (CTX), doxorubicin (Dox) and paclitaxel (PTX)] to effectively reduce cell viability were calculated. The effects of combination treatments of IONP-LPrA2 and chemotherapeutics on cell viability were determined. RESULTS Western blot analysis of coupling reaction products identified IONP-LPrA2 at approximately 100 kD. IONP-LPrA2 significantly decreased leptin-induced pSTAT3 levels in HCC1806 cells and drastically decreased cyclin D1 levels in all cell lines. IONP-LPrA2 significantly reduced leptin-induced S phase progression and cell proliferation in all breast cancer cell lines and the formation of tumorspheres in MDA-MB-231 cells. Also, IONP-LPrA2 showed an additive effect on the reduction of breast cancer cell survival with chemotherapeutics. Cis plus IONP-LPrA2 produced a significant reduction in the survival of MDA-MB-231 and HCC1806 cells. CTX plus IONP-LPrA2 caused a significant decrease in the survival of MDA-MB-231 cells. Dox plus IONP-LPrA2 caused a marked reduction in the survival of HCC1806 cells. Although, PTX plus IONP-LPrA2 did not have a major effect on the viability of the breast cancer cells when compared to PTX

  1. A novel CCR2 antagonist inhibits atherogenesis in apoE deficient mice by achieving high receptor occupancy. (United States)

    Bot, Ilze; Ortiz Zacarías, Natalia V; de Witte, Wilhelmus E A; de Vries, Henk; van Santbrink, Peter J; van der Velden, Daniël; Kröner, Mara J; van der Berg, Dirk-Jan; Stamos, Dean; de Lange, Elizabeth C M; Kuiper, Johan; IJzerman, Adriaan P; Heitman, Laura H


    CC Chemokine Receptor 2 (CCR2) and its endogenous ligand CCL2 are involved in a number of diseases, including atherosclerosis. Several CCR2 antagonists have been developed as potential therapeutic agents, however their in vivo clinical efficacy was limited. In this report, we aimed to determine whether 15a, an antagonist with a long residence time on the human CCR2, is effective in inhibiting the development of atherosclerosis in a mouse disease model. First, radioligand binding assays were performed to determine affinity and binding kinetics of 15a on murine CCR2. To assess the in vivo efficacy, western-type diet fed apoE(-/-) mice were treated daily with 15a or vehicle as control. Treatment with 15a reduced the amount of circulating CCR2(+) monocytes and the size of the atherosclerotic plaques in both the carotid artery and the aortic root. We then showed that the long pharmacokinetic half-life of 15a combined with the high drug concentrations ensured prolonged CCR2 occupancy. These data render 15a a promising compound for drug development and confirms high receptor occupancy as a key parameter when targeting chemokine receptors.

  2. 5-HT3 and 5-HT4 antagonists inhibit peristaltic contractions in guinea-pig distal colon by mechanisms independent of endogenous 5-HT

    Directory of Open Access Journals (Sweden)

    Tiong Cheng Sia


    Full Text Available Recent studies have shown that endogenous serotonin is not required for colonic peristalsis in vitro, nor gastrointestinal (GI transit in vivo. However, antagonists of 5-Hydroxytryptamine (5-HT receptors can inhibit peristalsis and GI-transit in mammals, including humans. This raises the question of how these antagonists inhibit GI-motility and transit, if depletion of endogenous 5-HT does not cause any significant inhibitory changes to either GI-motility or transit ? We investigated the mechanism by which 5-HT3 and 5-HT4 antagonists inhibit distension-evoked peristaltic contractions in guinea-pig distal colon. In control animals, repetitive peristaltic contractions of the circular muscle were evoked in response to fixed fecal pellet distension. Distension-evoked peristaltic contractions were unaffected in animals with mucosa and submucosal plexus removed, that were also treated with reserpine (to deplete neuronal 5-HT. In control animals, peristaltic contractions were blocked temporarily by ondansetron (1-10µM and SDZ-205-557 (1-10µM in many animals. Interestingly, after this temporary blockade, and whilst in the continued presence of these antagonists, peristaltic contractions recovered, with characteristics no different from controls. Surprisingly, similar effects were seen in mucosa-free preparations, which had no detectable 5-HT, as detected by mass spectrometry. In summary, distension-evoked peristaltic reflex contractions of the circular muscle layer of the guinea-pig colon can be inhibited temporarily, or permanently, in the same preparation by selective 5-HT3 and 5-HT4 antagonists, depending on the concentration of the antagonists applied. These effects also occur in preparations that lack any detectable 5-HT. We suggest caution should be exercised when interpreting the effects of 5-HT3 and 5-HT4 antagonists; and the role of endogenous 5-HT, in the generation of distension-evoked colonic peristalsis.

  3. The fungus-growing termite Macrotermes natalensis harbors bacillaene-producing Bacillus sp. that inhibit potentially antagonistic fungi. (United States)

    Um, Soohyun; Fraimout, Antoine; Sapountzis, Panagiotis; Oh, Dong-Chan; Poulsen, Michael


    The ancient fungus-growing termite (Mactrotermitinae) symbiosis involves the obligate association between a lineage of higher termites and basidiomycete Termitomyces cultivar fungi. Our investigation of the fungus-growing termite Macrotermes natalensis shows that Bacillus strains from M. natalensis colonies produce a single major antibiotic, bacillaene A (1), which selectively inhibits known and putatively antagonistic fungi of Termitomyces. Comparative analyses of the genomes of symbiotic Bacillus strains revealed that they are phylogenetically closely related to Bacillus subtilis, their genomes have high homology with more than 90% of ORFs being 100% identical, and the sequence identities across the biosynthetic gene cluster for bacillaene are higher between termite-associated strains than to the cluster previously reported in B. subtilis. Our findings suggest that this lineage of antibiotic-producing Bacillus may be a defensive symbiont involved in the protection of the fungus-growing termite cultivar.

  4. Inhibition of CPU0213, a Dual Endothelin Receptor Antagonist, on Apoptosis via Nox4-Dependent ROS in HK-2 Cells

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    Qing Li


    Full Text Available Background/Aims: Our previous studies have indicated that a novel endothelin receptor antagonist CPU0213 effectively normalized renal function in diabetic nephropathy. However, the molecular mechanisms mediating the nephroprotective role of CPU0213 remain unknown. Methods and Results: In the present study, we first detected the role of CPU0213 on apoptosis in human renal tubular epithelial cell (HK-2. It was shown that high glucose significantly increased the protein expression of Bax and decreased Bcl-2 protein in HK-2 cells, which was reversed by CPU0213. The percentage of HK-2 cells that showed Annexin V-FITC binding was markedly suppressed by CPU0213, which confirmed the inhibitory role of CPU0213 on apoptosis. Given the regulation of endothelin (ET system to oxidative stress, we determined the role of redox signaling in the regulation of CPU0213 on apoptosis. It was demonstrated that the production of superoxide (O2-. was substantially attenuated by CPU0213 treatment in HK-2 cells. We further found that CPU0213 dramatically inhibited expression of Nox4 protein, which gene silencing mimicked the role of CPU0213 on the apoptosis under high glucose stimulation. We finally examined the role of CPU0213 on ET-1 receptors and found that high glucose-induced protein expression of endothelin A and B receptors was dramatically inhibited by CPU0213. Conclusion: Taken together, these results suggest that this Nox4-dependenet O2- production is critical for the apoptosis of HK-2 cells in high glucose. Endothelin receptor antagonist CPU0213 has an anti-apoptosis role through Nox4-dependent O2-.production, which address the nephroprotective role of CPU0213 in diabetic nephropathy.

  5. Antagonist peptides of human interferon-α2b isolated from phage display library inhibit interferon induced antiviral activity

    Institute of Scientific and Technical Information of China (English)

    Wang TIAN; Gang BAI; Zheng-he LI; Wen-bo YANG


    Aim: To screen human interferon (IFN)-α2b antagonist peptides from a phage displayed heptapeptide library. Methods: WISH cells and polyclonal anti-IFN-α2b antibodies were used to select IFN receptor-binding peptides from a phage displayed heptapeptide library. The specific binding of phage clones was examined by phage ELISA and immunohistochemistry. The specific binding activities of synthetic peptides to WISH cells were detected by competition assay. Effects of synthetic peptides to IFN-induced antiviral activity were analyzed by evaluating the cytopathic effect (CPE) using the MTT method. Results: Twenty-three positive clones were obtained after seven rounds of selection. Ten clones were randomly picked from the positive clones and were sequenced. The corresponding amino acid sequences suggested 3 groups homologous to the 3 domains of IFN-α2b, defined by residues 24-41, 43-49, and 148-158 of IFN-α2b. As they presented as corresponding to IFN receptor-binding domains, AB loop and E helix, clone № 26 and 35 were chosen for further characterization and shown to bind to WISH cells. Two peptides corresponding to clone № 26 and 35, designated SP-7(SLSPGLP) and FY-7(FSAPVRY) were shown to compete with GFP-IFN-α2b for binding to its receptor and to inhibit the IFN-α2b-induced antiviral activity. Conclusion: Both IFN-α2b antagonist peptides, SP-7 and FY-7, were able to inhibit the IFN-induced antiviral activity, and could be helpful in laying the foundation for the molecular mechanism of the interaction between IFN and its receptor.

  6. Kinin B1 receptor antagonists inhibit diabetes-induced hyperalgesia in mice. (United States)

    Gabra, Bichoy H; Sirois, Pierre


    Insulin-dependent diabetes mellitus (type 1 diabetes) is an inflammatory autoimmune disease associated with vascular permeability changes leading to many complications including nephropathy, retinopathy, neuropathy, hypertension and hyperalgesia. The bradykinin B(1) receptors (BKB(1)-R) were recently found to be upregulated alongside the development of type 1 diabetes and to be involved in its complications. Kinins are important mediators of a variety of biological effects including cardiovascular homeostasis, inflammation and nociception. In the present study, we studied the effect of a selective BKB(1)-R agonist desArg(9)-BK (DBK) and two selective receptor antagonists, the R-715 (Ac-Lys-[D-beta Nal(7), Ile(8)] desArg(9)-BK) and the R-954 (Ac-Orn-[Oic(2), alphaMe Phe(5), D-beta Nal(7), Ile(8)] desArg(9)-BK) on diabetic hyperalgesia. Type 1 diabetes was induced in male CD-1 mice via a single injection of streptozotocin (STZ, 200mg/kg, i.p.), one week before the test. Nociception, a measure of hyperalgesia, was assessed using the plantar stimulation (Hargreaves) and the tail-immersion tests. The induction of type 1 diabetes provoked a significant hyperalgesic activity in diabetic mice, causing an 11% decrease in plantar stimulation reaction time and 13% decrease in tail-immersion reaction time, compared to normal mice. Following acute administration of R-715 (100-600 microg/kg, i.p.), or R-954 (50-400 microg/kg, i.p.), the STZ-induced hyperalgesic activity was blocked in a dose-dependent manner and the hot plate and tail-immersion latencies of diabetic mice returned to normal values observed in control healthy mice. In addition, the acute administration of DBK (400 microg/kg, i.p.) significantly potentiated diabetes-induced hyperalgesia, an effect that was totally reversed by R-715 (1.6-2.4 mg/kg, i.p.) and R-954 (0.8-1.2mg/kg, i.p.). These results provide further evidence for the implication of the BKB(1)-R in type 1 diabetic hyperalgesia and suggest a novel

  7. Novel synthetic antagonists of canonical Wnt signaling inhibit colorectal cancer cell growth. (United States)

    Waaler, Jo; Machon, Ondrej; von Kries, Jens Peter; Wilson, Steven Ray; Lundenes, Elsa; Wedlich, Doris; Gradl, Dietmar; Paulsen, Jan Erik; Machonova, Olga; Dembinski, Jennifer L; Dinh, Huyen; Krauss, Stefan


    Canonical Wnt signaling is deregulated in several types of human cancer where it plays a central role in tumor cell growth and progression. Here we report the identification of 2 new small molecules that specifically inhibit canonical Wnt pathway at the level of the destruction complex. Specificity was verified in various cellular reporter systems, a Xenopus double-axis formation assay and a gene expression profile analysis. In human colorectal cancer (CRC) cells, the new compounds JW67 and JW74 rapidly reduced active β-catenin with a subsequent downregulation of Wnt target genes, including AXIN2, SP5, and NKD1. Notably, AXIN2 protein levels were strongly increased after compound exposure. Long-term treatment with JW74 inhibited the growth of tumor cells in both a mouse xenograft model of CRC and in Apc(Min) mice (multiple intestinal neoplasia, Min). Our findings rationalize further preclinical and clinical evaluation of these new compounds as novel modalities for cancer treatment.

  8. Hedgehog signaling antagonist GDC-0449 (Vismodegib inhibits pancreatic cancer stem cell characteristics: molecular mechanisms.

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    Brahma N Singh

    Full Text Available BACKGROUND: Recent evidence from in vitro and in vivo studies has demonstrated that aberrant reactivation of the Sonic Hedgehog (SHH signaling pathway regulates genes that promote cellular proliferation in various human cancer stem cells (CSCs. Therefore, the chemotherapeutic agents that inhibit activation of Gli transcription factors have emerged as promising novel therapeutic drugs for pancreatic cancer. GDC-0449 (Vismodegib, orally administrable molecule belonging to the 2-arylpyridine class, inhibits SHH signaling pathway by blocking the activities of Smoothened. The objectives of this study were to examine the molecular mechanisms by which GDC-0449 regulates human pancreatic CSC characteristics in vitro. METHODOLOGY/PRINCIPAL FINDINGS: GDC-0499 inhibited cell viability and induced apoptosis in three pancreatic cancer cell lines and pancreatic CSCs. This inhibitor also suppressed cell viability, Gli-DNA binding and transcriptional activities, and induced apoptosis through caspase-3 activation and PARP cleavage in pancreatic CSCs. GDC-0449-induced apoptosis in CSCs showed increased Fas expression and decreased expression of PDGFRα. Furthermore, Bcl-2 was down-regulated whereas TRAIL-R1/DR4 and TRAIL-R2/DR5 expression was increased following the treatment of CSCs with GDC-0449. Suppression of both Gli1 plus Gli2 by shRNA mimicked the changes in cell viability, spheroid formation, apoptosis and gene expression observed in GDC-0449-treated pancreatic CSCs. Thus, activated Gli genes repress DRs and Fas expressions, up-regulate the expressions of Bcl-2 and PDGFRα and facilitate cell survival. CONCLUSIONS/SIGNIFICANCE: These data suggest that GDC-0499 can be used for the management of pancreatic cancer by targeting pancreatic CSCs.

  9. Ciproxifan, a histamine H3 receptor antagonist and inverse agonist, presynaptically inhibits glutamate release in rat hippocampus. (United States)

    Lu, Cheng-Wei; Lin, Tzu-Yu; Chang, Chia-Ying; Huang, Shu-Kuei; Wang, Su-Jane


    Ciproxifan is an H3 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(2+)-dependent glutamate release and cytosolic Ca(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 Cav2.2 (N-type) and Cav2.1 (P/Q-type) channel blocker ω-conotoxin MVIIC, but was not affected by the intracellular Ca(2+)-release inhibitors dantrolene and CGP37157. Furthermore, the phospholipase A2 (PLA2) inhibitor OBAA, prostaglandin E2 (PGE2), PGE2 subtype 2 (EP2) 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 H3 receptors present on hippocampal nerve terminals, reduces voltage-dependent Ca(2+) entry by diminishing PLA2/PGE2/EP2 receptor pathway, which subsequently suppresses the ERK/synapsin I cascade to decrease the evoked glutamate release.

  10. Corticotropin-releasing factor antagonist attenuates stress-induced inhibition of seasonal ovarian recrudescence in the lizard Mabuya carinata. (United States)

    Ganesh, C B; Yajurvedi, H N


    Whether administration of the corticotropin-releasing factor (CRF) antagonist alpha-helical CRF(9-41) (hCRF) prevents stress response of the ovary, the oviduct, the adrenals, and the spleen was studied in the lizard Mabuya carinata. Stressors (handling, chasing, and noise) applied randomly, five times a day, for 1 month to lizards during the recrudescence phase of the ovarian cycle caused a significant increase in mean nuclear diameter of the adrenal cortical cells and a significant reduction in mean number of islands of white pulp in the spleen. These results, albeit indirectly, indicated an activation of the adrenal gland and immune suppression. There was a significant decrease in the mean relative weight of the ovary and the oviduct and in the mean number of oocytes and the primordial follicles compared to those of controls. Furthermore, vitellogenic follicles were absent in the ovary of lizards exposed to stressors in contrast to their presence in controls. However, administration of hCRF to the lizards exposed to stressors (stress + hCRF) resulted in vitellogenesis and follicular growth. The mean relative weight of the ovary and the oviduct and the mean number of oocytes and the primordial follicles in stress + hCRF-treated lizards were significantly higher than those in the lizards exposed to stressors, whereas they did not significantly differ from those of controls. The results indicate that hCRF attenuates stress-induced inhibition of ovarian follicular and oviductal development in M. carinata. To the best of our knowledge, this is the first report revealing that CRF antagonist can prevent ovarian stress response in lower vertebrates.

  11. Designer Leptin Receptor Antagonist Allo-aca Inhibits VEGF Effects in Ophthalmic Neoangiogenesis Models (United States)

    Coroniti, Roberta; Fario, Rafal; Nuno, Didier J.; Otvos, Laszlo; Scolaro, Laura; Surmacz, Eva


    Experimental and clinical data suggest that pro-angiogenic, pro-inflammatory and mitogenic cytokine leptin can be implicated in ocular neovascularization and other eye pathologies. At least in part, leptin action appears to be mediated through functional interplay with vascular endothelial growth factor (VEGF). VEGF is a potent regulator of neoangiogenesis and vascular leakage with a proven role in conditions such as proliferative diabetic retinopathy, age-related macular degeneration and diabetic macular edema. Accordingly, drugs targeting VEGF are becoming mainstream treatments for these diseases. The crosstalk between leptin and VEGF has been noted in different tissues, but its involvement in the development of eye pathologies is unclear. Leptin is coexpressed with VEGF during ocular neovascularization and can potentiate VEGF synthesis and angiogenic function. However, whether or not VEGF regulates leptin expression or signaling has never been studied. Consequently, we addressed this aspect of leptin/VEGF crosstalk in ocular models, focusing on therapeutic exploration of underlying mechanisms. Here we show, for the first time, that in retinal (RF/6A) and corneal (BCE) endothelial cells, VEGF (100 ng/mL, 24 h) stimulated leptin mRNA synthesis by 70 and 30%, respectively, and protein expression by 56 and 28%, respectively. In parallel, VEGF induced RF/6A and BCE cell growth by 33 and 20%, respectively. In addition, VEGF upregulated chemotaxis and chemokinesis in retinal cells by ~40%. VEGF-dependent proliferation and migration were significantly reduced in the presence of the leptin receptor antagonist, Allo-aca, at 100–250 nmol/L concentrations. Furthermore, Allo-aca suppressed VEGF-dependent long-term (24 h), but not acute (15 min) stimulation of the Akt and ERK1/2 signaling pathways. The efficacy of Allo-aca was validated in the rat laser-induced choroidal neovascularization model where the compound (5 μg/eye) significantly reduced pathological

  12. Fully human antagonistic antibodies against CCR4 potently inhibit cell signaling and chemotaxis.

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    Urs B Hagemann

    Full Text Available CC chemokine receptor 4 (CCR4 represents a potentially important target for cancer immunotherapy due to its expression on tumor infiltrating immune cells including regulatory T cells (Tregs and on tumor cells in several cancer types and its role in metastasis.Using phage display, human antibody library, affinity maturation and a cell-based antibody selection strategy, the antibody variants against human CCR4 were generated. These antibodies effectively competed with ligand binding, were able to block ligand-induced signaling and cell migration, and demonstrated efficient killing of CCR4-positive tumor cells via ADCC and phagocytosis. In a mouse model of human T-cell lymphoma, significant survival benefit was demonstrated for animals treated with the newly selected anti-CCR4 antibodies.For the first time, successful generation of anti- G-protein coupled chemokine receptor (GPCR antibodies using human non-immune library and phage display on GPCR-expressing cells was demonstrated. The generated anti-CCR4 antibodies possess a dual mode of action (inhibition of ligand-induced signaling and antibody-directed tumor cell killing. The data demonstrate that the anti-tumor activity in vivo is mediated, at least in part, through Fc-receptor dependent effector mechanisms, such as ADCC and phagocytosis. Anti-CC chemokine receptor 4 antibodies inhibiting receptor signaling have potential as immunomodulatory antibodies for cancer.

  13. Inhibition of Drp1-dependent mitochondrial fragmentation and apoptosis by a polypeptide antagonist of calcineurin (United States)

    Cereghetti, GM; Costa, V; Scorrano, L


    During apoptosis, mitochondria lose their membrane potential and undergo fragmentation around the time of release of cytochrome c. Apoptotic fission is at least in part sustained by the translocation of dynamin-related protein 1 (Drp1), normally located in the cytosol, to mitochondria. This process depends on dephosphorylation of Drp1 by the phosphatase calcineurin. Here, we report the identification of a novel inhibitor of this process. A polypeptide (PPD1) from the immunophilin FKBP52 inhibits calcineurin activation triggered by mitochondrial dysfunction. PPD1 blocks Drp1 translocation to mitochondria and fragmentation of the organelle. PPD1 delays apoptosis by intrinsic stimuli by preventing fragmentation and release of cytochrome c. Cells expressing PPD1 display enhanced clonogenic ability after exposure to staurosporine. A genetic analysis revealed that the activity of PPD1 is independent of the BH3-only protein BAD, another target of calcineurin during apoptosis, and is not additive to inhibition of Drp1. Thus, PPD1 is a novel inhibitor of apoptosis that elucidates the function of calcineurin-dependent mitochondrial fragmentation in the amplification of cell death. PMID:20489733

  14. Inhibition of human immunodeficiency virus replication by a dual CCR5/CXCR4 antagonist

    DEFF Research Database (Denmark)

    Princen, Katrien; Hatse, Sigrid; Vermeire, Kurt;


    Here we report that the N-pyridinylmethyl cyclam analog AMD3451 has antiviral activity against a wide variety of R5, R5/X4, and X4 strains of human immunodeficiency virus type 1 (HIV-1) and HIV-2 (50% inhibitory concentration [IC(50)] ranging from 1.2 to 26.5 microM) in various T-cell lines, CCR5...... at the virus entry stage. AMD3451 dose-dependently inhibited the intracellular Ca(2+) signaling induced by the CXCR4 ligand CXCL12 in T-lymphocytic cells and in CXCR4-transfected cells, as well as the Ca(2+) flux induced by the CCR5 ligands CCL5, CCL3, and CCL4 in CCR5-transfected cells. The compound did...

  15. Blocking S1P interaction with S1P{sub 1} receptor by a novel competitive S1P{sub 1}-selective antagonist inhibits angiogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Yasuyuki, E-mail: [Department of Molecular Function and Pharmacology Laboratories, Taisho Pharmaceutical Co. Ltd., 1-403 Saitama, Saitama 331-9530 (Japan); Ueda, Yasuji; Ohtake, Hidenori; Ono, Naoya; Takayama, Tetsuo; Nakazawa, Kiyoshi [Department of Molecular Function and Pharmacology Laboratories, Taisho Pharmaceutical Co. Ltd., 1-403 Saitama, Saitama 331-9530 (Japan); Igarashi, Yasuyuki [Laboratory of Biomembrane and Biofunctional Chemistry, Hokkaido University, Sapporo, Hokkaido 060-0812 (Japan); Goitsuka, Ryo [Division of Development and Aging, Research Institute for Biological Sciences, Tokyo University of Science, Noda, Chiba 278-0022 (Japan)


    Highlights: Black-Right-Pointing-Pointer The effect of a newly developed S1P{sub 1}-selective antagonist on angiogenic responses. Black-Right-Pointing-Pointer S1P{sub 1} is a critical component of VEGF-related angiogenic responses. Black-Right-Pointing-Pointer S1P{sub 1}-selective antagonist showed in vitro activity to inhibit angiogenesis. Black-Right-Pointing-Pointer S1P{sub 1}-selective antagonist showed in vivo activity to inhibit angiogenesis. Black-Right-Pointing-Pointer The efficacy of S1P{sub 1}-selective antagonist for anti-cancer therapies. -- Abstract: Sphingosine 1-phosphate receptor type 1 (S1P{sub 1}) was shown to be essential for vascular maturation during embryonic development and it has been demonstrated that substantial crosstalk exists between S1P{sub 1} and other pro-angiogenic growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor. We developed a novel S1P{sub 1}-selective antagonist, TASP0277308, which is structurally unrelated to S1P as well as previously described S1P{sub 1} antagonists. TASP0277308 inhibited S1P- as well as VEGF-induced cellular responses, including migration and proliferation of human umbilical vein endothelial cells. Furthermore, TASP0277308 effectively blocked a VEGF-induced tube formation in vitro and significantly suppressed tumor cell-induced angiogenesis in vivo. These findings revealed that S1P{sub 1} is a critical component of VEGF-related angiogenic responses and also provide evidence for the efficacy of TASP0277308 for anti-cancer therapies.

  16. Telomerase antagonist imetelstat inhibits esophageal cancer cell growth and increases radiation-induced DNA breaks. (United States)

    Wu, Xuping; Smavadati, Shirin; Nordfjäll, Katarina; Karlsson, Krister; Qvarnström, Fredrik; Simonsson, Martin; Bergqvist, Michael; Gryaznov, Sergei; Ekman, Simon; Paulsson-Karlsson, Ylva


    Telomerase is mainly active in human tumor cells, which provides an opportunity for a therapeutic window on telomerase targeting. We sought to evaluate the potential of the thio-phosphoramidate oligonucleotide inhibitor of telomerase, imetelstat, as a drug candidate for treatment of esophageal cancer. Our results showed that imetelstat inhibited telomerase activity in a dose-dependent manner in esophageal cancer cells. After only 1 week of imetelstat treatment, a reduction of colony formation ability of esophageal cancer cells was observed. Furthermore, long-term treatment with imetelstat decreased cell growth of esophageal cancer cells with different kinetics regarding telomere lengths. Short-term imetelstat treatment also increased γ-H2AX and 53BP1 foci staining in the esophageal cancer cell lines indicating a possible induction of DNA double strand breaks (DSBs). We also found that pre-treatment with imetelstat led to increased number and size of 53BP1 foci after ionizing radiation. The increase of 53BP1 foci number was especially pronounced during the first 1h of repair whereas the increase of foci size was prominent later on. This study supports the potential of imetelstat as a therapeutic agent for the treatment of esophageal cancer.

  17. Selective and rapid monitoring of dual platelet inhibition by aspirin and P2Y12 antagonists by using multiple electrode aggregometry

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    Lorenz Reinhard


    Full Text Available Abstract Background Poor platelet inhibition by aspirin or clopidogrel has been associated with adverse outcomes in patients with cardiovascular diseases. A reliable and facile assay to measure platelet inhibition after treatment with aspirin and a P2Y12 antagonist is lacking. Multiple electrode aggregometry (MEA, which is being increasingly used in clinical studies, is sensitive to platelet inhibition by aspirin and clopidogrel, but a critical evaluation of MEA monitoring of dual anti-platelet therapy with aspirin and P2Y12 antagonists is missing. Design and Methods By performing in vitro and ex vivo experiments, we evaluated in healthy subjects the feasibility of using MEA to monitor platelet inhibition of P2Y12 antagonists (clopidogrel in vivo, cangrelor in vitro and aspirin (100 mg per day in vivo, and 1 mM or 5.4 mM in vitro alone, and in combination. Statistical analyses were performed by the Mann-Whitney rank sum test, student' t-test, analysis of variance followed by the Holm-Sidak test, where appropriate. Results ADP-induced platelet aggregation in hirudin-anticoagulated blood was inhibited by 99.3 ± 1.4% by in vitro addition of cangrelor (100 nM; p 95% and 100 ± 3.2%, respectively (p in vitro or ex vivo. Oral intake of clopidogrel did not significantly reduce AA-induced aggregation, but P2Y12 blockade by cangrelor (100 nM in vitro diminished AA-stimulated aggregation by 53 ± 26% (p Conclusions Selective platelet inhibition by aspirin and P2Y12 antagonists alone and in combination can be rapidly measured by MEA. We suggest that dual anti-platelet therapy with these two types of anti-platelet drugs can be optimized individually by measuring platelet responsiveness to ADP and AA with MEA before and after drug intake.

  18. Hypoxic pulmonary vasoconstriction in isolated rat pulmonary arteries is not inhibited by antagonists of H2 S-synthesizing pathways. (United States)

    Prieto-Lloret, Jesus; Shaifta, Yasin; Ward, Jeremy P T; Aaronson, Philip I


    An increase in the H2 S (hydrogen sulphide, hereafter sulphide) concentration in pulmonary artery smooth muscle cells (PASMCs) has been proposed to mediate hypoxic pulmonary vasoconstriction (HPV). We evaluated this hypothesis in isolated rat intrapulmonary arteries (IPAs) by examining the effects of the sulphide precursor cysteine and sulphide-synthesis blockers on HPV and also on normoxic pulmonary vasoconstriction (NPV) stimulated by prostaglandin F2α (PGF2α ) and by the drug LY83583, which causes contraction in IPAs by increasing cellular reactive oxygen species levels. Experiments with several blockers of cystathionine γ-lyase (CSE), the enzyme responsible for sulphide synthesis in the vasculature, demonstrated that propargylglycine (PAG, 1 mm) had little or no effect on the NPV caused by PGF2α or LY83583. Conversely, other CSE antagonists tested, aminooxyacetic acid (AOAA, 100 μm), β-cyanoalanine (BCA, 500 μm) and hydroxylamine (HA, 100 μm), altered the NPV to PGF2α (BCA increased, HA inhibited) and/or LY83583 (BCA increased, AOAA and HA inhibited). Preincubating IPAs in physiological saline solution (PSS) containing 1 mm cysteine increased the amplitude of the NPV to PGF2(α) by ∼50%, and had a similar effect on HPV elicited by hypoxic challenge with 0% O2 . The enhancement of both responses by cysteine was abolished by pretreatment with 1 mm PAG. Measurements carried out with an amperometric electrode demonstrated that incubation with 1 mm cysteine under anoxic conditions (to minimize sulphide oxidation) greatly potentiated the release of sulphide from pieces of rat liver and that this release was strongly antagonized by PAG, indicating that at this concentration PAG could enter cells intact and antagonize CSE. PAG at 1 mm had no effect on HPV recorded in control PSS, or in PSS supplemented with physiological concentrations of cysteine (10 μm), cystine (50 μm) and glutamate (100 μm) in order to prevent the possible depletion of intracellular

  19. A novel muscarinic antagonist R2HBJJ inhibits non-small cell lung cancer cell growth and arrests the cell cycle in G0/G1.

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    Nan Hua

    Full Text Available Lung cancers express the cholinergic autocrine loop, which facilitates the progression of cancer cells. The antagonists of mAChRs have been demonstrated to depress the growth of small cell lung cancers (SCLCs. In this study we intended to investigate the growth inhibitory effect of R2HBJJ, a novel muscarinic antagonist, on non-small cell lung cancer (NSCLC cells and the possible mechanisms. The competitive binding assay revealed that R2HBJJ had a high affinity to M3 and M1 AChRs. R2HBJJ presented a strong anticholinergic activity on carbachol-induced contraction of guinea-pig trachea. R2HBJJ markedly suppressed the growth of NSCLC cells, such as H1299, H460 and H157. In H1299 cells, both R2HBJJ and its leading compound R2-PHC displayed significant anti-proliferative activity as M3 receptor antagonist darifenacin. Exogenous replenish of ACh could attenuate R2HBJJ-induced growth inhibition. Silencing M3 receptor or ChAT by specific-siRNAs resulted in a growth inhibition of 55.5% and 37.9% on H1299 cells 96 h post transfection, respectively. Further studies revealed that treatment with R2HBJJ arrested the cell cycle in G0/G1 by down-regulation of cyclin D1-CDK4/6-Rb. Therefore, the current study reveals that NSCLC cells express an autocrine and paracrine cholinergic system which stimulates the growth of NSCLC cells. R2HBJJ, as a novel mAChRs antagonist, can block the local cholinergic loop by antagonizing predominantly M3 receptors and inhibit NSCLC cell growth, which suggest that M3 receptor antagonist might be a potential chemotherapeutic regimen for NSCLC.

  20. β-Adrenergic receptor antagonists inhibit vasculogenesis of embryonic stem cells by downregulation of nitric oxide generation and interference with VEGF signalling. (United States)

    Sharifpanah, Fatemeh; Saliu, Fatjon; Bekhite, Mohamed M; Wartenberg, Maria; Sauer, Heinrich


    The β-adrenoceptor antagonist Propranolol has been successfully used to treat infantile hemangioma. However, its mechanism of action is so far unknown. The hypothesis of this research was that β-adrenoceptor antagonists may interfere with endothelial cell differentiation of stem cells. Specifically, the effects of the non-specific β-adrenergic receptor (β-adrenoceptor) antagonist Propranolol, the β1-adrenoceptor-specific antagonist Atenolol and the β2-adrenoceptor-specific antagonist ICI118,551 on vasculogenesis of mouse embryonic stem (ES) cells were investigated. All three β-blockers dose-dependently downregulated formation of capillary structures in ES cell-derived embryoid bodies and decreased the expression of the vascular cell markers CD31 and VE-cadherin. Furthermore, β-blockers downregulated the expression of fibroblast growth factor-2 (FGF-2), hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor 165 (VEGF165), VEGF receptor 2 (VEGF-R2) and phospho VEGF-R2, as well as neuropilin 1 (NRP1) and plexin-B1 which are essential modulators of embryonic angiogenesis with additional roles in vessel remodelling and arteriogenesis. Under conditions of β-adrenoceptor inhibition, the endogenous generation of nitric oxide (NO) as well as the phosphorylation of endothelial nitric oxide synthase (eNOS) was decreased in embryoid bodies, whereas an increase in NO generation was observed with the NO donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP). Consequently, vasculogenesis of ES cells was restored upon treatment of differentiating ES cells with β-adrenoceptor antagonists in the presence of NO donor. In summary, our data suggest that β-blockers impair vasculogenesis of ES cells by interfering with NO generation which could be the explanation for their anti-angiogenic effects in infantile hemangioma.

  1. LINGO-1-mediated inhibition of oligodendrocyte differentiation does not require the leucine-rich repeats and is reversed by p75(NTR) antagonists. (United States)

    Bourikas, Dimitris; Mir, Anis; Walmsley, Adrian Robert


    LINGO-1 is a potent negative regulator of oligodendrocyte differentiation and hence may play a pivotal restrictive role during remyelination in demyelinating diseases such as multiple sclerosis. However, little is known as to which stages of oligodendrocyte differentiation are inhibited by LINGO-1, which domains of the protein are involved and whether accessory proteins are required. Here, we show that LINGO-1 expression in the human oligodendroglial cell line MO3.13 inhibited process extension and this was reversed by an anti-LINGO-1 antibody or the antagonist LINGO-1-Fc. LINGO-1 expression was also found to inhibit myelin basic protein transcription in the rat oligodendroglial cell line CG4. Both of these inhibitory actions of LINGO-1 were abrogated by deletion of the entire ectodomain or cytoplasmic domains but, surprisingly, were unaffected by deletion of the leucine-rich repeats (LRRs). As in neurons, LINGO-1 physically associated with endogenous p75(NTR) in MO3.13 cells and, correspondingly, its inhibition of process extension was reversed by antagonists of p75(NTR). Thus, LINGO-1 inhibits multiple aspects of oligodendrocyte differentiation independently of the LRRs via a process that requires p75(NTR) signalling.

  2. Skin-targeted inhibition of PPAR β/δ by selective antagonists to treat PPAR β/δ-mediated psoriasis-like skin disease in vivo.

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    Katrin Hack

    Full Text Available We have previously shown that peroxisome proliferator activating receptor ß/δ (PPAR β/δ is overexpressed in psoriasis. PPAR β/δ is not present in adult epidermis of mice. Targeted expression of PPAR β/δ and activation by a selective synthetic agonist is sufficient to induce an inflammatory skin disease resembling psoriasis. Several signalling pathways dysregulated in psoriasis are replicated in this model, suggesting that PPAR β/δ activation contributes to psoriasis pathogenesis. Thus, inhibition of PPAR β/δ might harbour therapeutical potential. Since PPAR β/δ has pleiotropic functions in metabolism, skin-targeted inhibition offer the potential of reducing systemic adverse effects. Here, we report that three selective PPAR β/δ antagonists, GSK0660, compound 3 h, and GSK3787 can be formulated for topical application to the skin and that their skin concentration can be accurately quantified using ultra-high performance liquid chromatography (UPLC/mass spectrometry. These antagonists show efficacy in our transgenic mouse model in reducing psoriasis-like changes triggered by activation of PPAR β/δ. PPAR β/δ antagonists GSK0660 and compound 3 do not exhibit systemic drug accumulation after prolonged application to the skin, nor do they induce inflammatory or irritant changes. Significantly, the irreversible PPAR β/δ antagonist (GSK3787 retains efficacy when applied topically only three times per week which could be of practical clinical usefulness. Our data suggest that topical inhibition of PPAR β/δ to treat psoriasis may warrant further exploration.

  3. Effects of the selective dopamine D(1) antagonists NNC 01-0112 and SCH 39166 on latent inhibition in the rat. (United States)

    Trimble, Karen M; Bell, Robert; King, David J


    Dopamine D(1) receptor blockade does not appear to be a prerequisite for antipsychotic activity since many clinically effective antipsychotics have little or no affinity for this receptor subtype. Clozapine, however, which has minimal liability for extrapyramidal symptoms, possesses affinities of similar order for D(1) and D(2) receptors. In earlier animal models used to predict antipsychotic effect, selective D(1) antagonists have shown effects similar to standard antipsychotics with preferential D(2) or mixed D(1)/D(2) antagonism. We investigated the effects of haloperidol (0.1 mg/kg) and two selective D(1) antagonists, NNC 01-0112 (0.05, 0.1 and 0.2 mg/kg) and SCH 39166 (0.02, 0.2 and 2.0 mg/kg), on latent inhibition (LI) in rats. LI is a behavioural paradigm in which repeated nonreinforced preexposure to a stimulus retards subsequent associations to that stimulus. Disrupted LI has been suggested as a model for the attentional deficits in schizophrenia. Using preexposure to a flashing light stimulus, which subsequently served as a conditioned stimulus for suppression of water licking, we demonstrated a clear LI effect with haloperidol but with neither of the two D(1) antagonists. Since selective D(1) antagonists are not clinically effective, these results add further credibility for the relevance of LI as an animal model of psychosis.

  4. QSAR study on maximal inhibition (Imax) of quaternary ammonium antagonists for S-(-)-nicotine-evoked dopamine release from dopaminergic nerve terminals in rat striatum. (United States)

    Zheng, Fang; McConnell, Matthew J; Zhan, Chang-Guo; Dwoskin, Linda P; Crooks, Peter A


    Maximal inhibition (I(max)) of the agonist effect is an important pharmacological property of inhibitors that interact with multiple receptor subtypes that are activated by the same agonist and which elicit the same functional response. This report represents the first QSAR study on a set of 66 mono- and bis-quaternary ammonium salts that act as antagonists at neuronal nicotinic acetylcholine receptors mediating nicotine-evoked dopamine release, conducted using multi-linear regression (MLR) and neural network (NN) analysis with the maximal inhibition (I(max)) values of the antagonists as target values. The statistical results for the generated MLR model were: r(2)=0.89, rmsd=9.01, q(2)=0.83 and loormsd=11.1; the statistical results for the generated NN model were: r(2)=0.89, rmsd=8.98, q(2)=0.83 and loormsd=11.2. The maximal inhibition values of the compounds exhibited a good correlation with the predictions made by the QSAR models developed, which provide a basis for rationalizing selection of compounds for synthesis in the discovery of effective and selective second generation inhibitors of nAChRs mediating nicotine-evoked dopamine release.

  5. Clopidogrel (Plavix®), a P2Y(12) receptor antagonist, inhibits bone cell function in vitro and decreases trabecular bone in vivo

    DEFF Research Database (Denmark)

    Syberg, Susanne; Brandao-Burch, Andrea; Patel, Jessal J


    Clopidogrel (Plavix®), a selective P2Y(12) receptor antagonist, is widely prescribed to reduce the risk of heart attack and stroke and acts via the inhibition of platelet aggregation. Accumulating evidence now suggests that extracellular nucleotides, signalling through P2 receptors, play a signif......Clopidogrel (Plavix®), a selective P2Y(12) receptor antagonist, is widely prescribed to reduce the risk of heart attack and stroke and acts via the inhibition of platelet aggregation. Accumulating evidence now suggests that extracellular nucleotides, signalling through P2 receptors, play...... a significant role in bone, modulating both osteoblast and osteoclast function. In this study, we investigated the effects of clopidogrel treatment on (1) bone cell formation, differentiation and activity in vitro; and, (2) trabecular and cortical bone parameters in vivo. P2Y(12) receptor expression...... by osteoblasts and osteoclasts was confirmed using qPCR and western blotting. Clopidogrel at 10µM and 25µM inhibited mineralised bone nodule formation by 50% and >85%, respectively. Clopidogrel slowed osteoblast proliferation with dose-dependent decreases in cell number (25-40%) evident in differentiating...

  6. Indolizidine (-)-235B' and related structural analogs: discovery of nicotinic receptor antagonists that inhibit nicotine-evoked [3H]dopamine release. (United States)

    Pivavarchyk, Marharyta; Smith, Andrew M; Zhang, Zhenfa; Zhou, Dejun; Wang, Xu; Toyooka, Naoki; Tsuneki, Hiroshi; Sasaoka, Toshiyasu; McIntosh, J Michael; Crooks, Peter A; Dwoskin, Linda P


    Although several therapeutic agents are available to aid in tobacco smoking cessation, relapse rates continue to be high, warranting the development of alternative pharmacotherapies. Nicotine-evoked dopamine release from its presynaptic terminals in the central nervous system leads to reward which maintains continued tobacco use. The ability of indolizidine (-)-235B' and a sub-library of structurally related analogs to inhibit nicotine-evoked [(3)H]dopamine release from rat striatal slices was determined in the current study. Indolizidine (-)-235B' inhibited nicotine-evoked [(3)H]dopamine release in a concentration-dependent manner (IC(50)=42 nM, I(max)=55%). Compound (-)-237D, the double bond-reduced analog, afforded the greatest inhibitory potency (IC(50)=0.18 nM, I(max)=76%), and was 233-fold more potent than indolizidine (-)-235B'. The des-8-methyl aza-analog of indolizidine (-)-235B', ZZ-272, also inhibited nicotine-evoked [(3)H]dopamine release (IC(50)=413 nM, I(max)=59%). Concomitant exposure to maximally effective concentrations of indolizidine (-)-235B', ZZ-272 or (-)-237D with a maximally effective concentration of α-conotoxin MII, a selective antagonist for α6β2-containing nicotinic receptors, resulted in inhibition of nicotine-evoked [(3)H]dopamine release no greater than that produced by each compound alone. The latter results suggest that indolizidine (-)-235B', (-)-237D, ZZ-272 and α-conotoxin MII inhibit the same α-conotoxin MII-sensitive nicotinic receptor subtypes. Thus, indolizidine (-)-235B' and its analogs act as antagonists of α6β2-nicotinic receptors and constitute a novel structural scaffold for the discovery of pharmacotherapies for smoking cessation.

  7. The GABAА receptors agonists and antagonists influence on formation of a latent inhibition at rats with different levels of anxiety


    A. V. Redkina; L. V. Loskutova; Т. A. Zamoshchina


    Latent inhibition phenomenon indexes the ability to ignore irrelevant stimuli. Disturbance of latent inhibition is registered in different psychiatric populations with pathology in the emotional and cognitive spheres. In our experiments latent inhibition was measured in a conditioned passive avoidance reaction in rats that previously received 0 or 20 conditioned stimuli exposures followed by foot shock. Latent inhibition was disrupted in high-anxiety rats and pathologically enhanced in low-an...

  8. Microinfusion of the non-competitive N-methyl-D-aspartate receptor antagonist MK-801 (dizocilpine) into the dorsal hippocampus of wistar rats does not affect latent inhibition and prepulse inhibition, but increases startle reaction and locomotor activity. (United States)

    Zhang, W N; Bast, T; Feldon, J


    Latent inhibition (the retarded conditioning to a stimulus following its repeated non-reinforced pre-exposure) and prepulse inhibition (the reduction in the startle response to an intense acoustic stimulus when this stimulus is immediately preceded by a prepulse) reflect cognitive and sensorimotor gating processes, respectively, and are deficient in schizophrenic patients. The disruption of latent inhibition and prepulse inhibition in the rat is used as an animal model for the attentional deficits associated with schizophrenia. The present study tested the extent to which latent inhibition and prepulse inhibition, startle reaction and locomotor activity in the open field were affected by infusing the non-competitive N-methyl-D-aspartate receptor antagonist MK-801 (dizocilpine) into the dorsal hippocampus of Wistar rats. We used the same dose of MK-801 (6.25microg/0.5microl per side) previously found to be effective in the disruption of prepulse inhibition when infused into the dorsal hippocampus of Sprague-Dawley rats [Bakshi V. P. and Geyer M. A. (1998) J. Neurosci. 18, 8394-8401; Bakshi V. P. and Geyer M. A. (1999) Neuroscience 92, 113-121]. Bilateral infusion of MK-801 into the dorsal hippocampus did not disrupt latent inhibition. Furthermore, in contrast to previous studies, we failed to find a significant disruption of prepulse inhibition after MK-801 infusion into the dorsal hippocampus, although MK-801 infusion was effective in increasing the startle amplitude as well as locomotor activity in an open field. From our results, we suggest that N-methyl-D-aspartate receptor-mediated processes within the dorsal hippocampus are not necessary for the normal maintenance of the attentional processes reflected by latent inhibition and prepulse inhibition.

  9. The P2Y(12 antagonists, 2MeSAMP and cangrelor, inhibit platelet activation through P2Y(12/G(i-dependent mechanism.

    Directory of Open Access Journals (Sweden)

    Binggang Xiang

    Full Text Available BACKGROUND: ADP is an important physiological agonist that induces integrin activation and platelet aggregation through its receptors P2Y(1 (Gα(q-coupled and P2Y(12 (Gα(i-coupled. P2Y(12 plays a critical role in platelet activation and thrombosis. Adenosine-based P2Y(12 antagonists, 2-methylthioadenosine 5'-monophosphate triethylammonium salt hydrate (2MeSAMP and Cangrelor (AR-C69931MX have been widely used to demonstrate the role of P2Y(12 in platelet function. Cangrelor is being evaluated in clinical trials of thrombotic diseases. However, a recent study reported that both 2MeSAMP and Cangrelor raise intra-platelet cAMP levels and inhibit platelet aggregation through a P2Y(12-independent mechanism. METHODOLOGY/PRINCIPAL FINDINGS: The present work, using P2Y(12 deficient mice, sought to clarify previous conflicting reports and to elucidate the mechanisms by which 2MeSAMP and Cangrelor inhibit platelet activation and thrombosis. 2MeSAMP and Cangrelor inhibited aggregation and ATP release of wild-type but not P2Y(12 deficient platelets. 2MeSAMP and Cangrelor neither raised intracellular cAMP concentrations nor induced phosphorylation of vasodilator-stimulated phosphoprotein (VASP in washed human or mouse platelets. Furthermore, unlike the activators (PGI(2 and forskolin of the cAMP pathway, 2MeSAMP and Cangrelor failed to inhibit Ca(2+ mobilization, Akt phosphorylation, and Rap1b activation in P2Y(12 deficient platelets. Importantly, while injection of Cangrelor inhibited thrombus formation in a FeCl(3-induced thrombosis model in wild-type mice, it failed to affect thrombus formation in P2Y(12 deficient mice. CONCLUSIONS: These data together demonstrate that 2MeSAMP and Cangrelor inhibit platelet function through the P2Y(12-dependent mechanism both in vitro and in vivo.

  10. Reduced maximal inhibition in phenotypic susceptibility assays indicates that viral strains resistant to the CCR5 antagonist maraviroc utilize inhibitor-bound receptor for entry. (United States)

    Westby, Mike; Smith-Burchnell, Caroline; Mori, Julie; Lewis, Marilyn; Mosley, Michael; Stockdale, Mark; Dorr, Patrick; Ciaramella, Giuseppe; Perros, Manos


    Maraviroc is a CCR5 antagonist in clinical development as one of a new class of antiretrovirals targeting human immunodeficiency virus type 1 (HIV-1) coreceptor binding. We investigated the mechanism of HIV resistance to maraviroc by using in vitro sequential passage and site-directed mutagenesis. Serial passage through increasing maraviroc concentrations failed to select maraviroc-resistant variants from some laboratory-adapted and clinical isolates of HIV-1. However, high-level resistance to maraviroc was selected from three of six primary isolates passaged in peripheral blood lymphocytes (PBL). The SF162 strain acquired resistance to maraviroc in both treated and control cultures; all resistant variants were able to use CXCR4 as a coreceptor. In contrast, maraviroc-resistant virus derived from isolates CC1/85 and RU570 remained CCR5 tropic, as evidenced by susceptibility to the CCR5 antagonist SCH-C, resistance to the CXCR4 antagonist AMD3100, and an inability to replicate in CCR5 Delta32/Delta32 PBL. Strain-specific mutations were identified in the V3 loop of maraviroc-resistant CC1/85 and RU570. The envelope-encoding region of maraviroc-resistant CC1/85 was inserted into an NL4-3 background. This recombinant virus was completely resistant to maraviroc but retained susceptibility to aplaviroc. Reverse mutation of gp120 residues 316 and 323 in the V3 loop (numbering from HXB2) to their original sequence restored wild-type susceptibility to maraviroc, while reversion of either mutation resulted in a partially sensitive virus with reduced maximal inhibition (plateau). The plateaus are consistent with the virus having acquired the ability to utilize maraviroc-bound receptor for entry. This hypothesis was further corroborated by the observation that a high concentration of maraviroc blocks the activity of aplaviroc against maraviroc-resistant virus.

  11. Adenosine AA Receptor Antagonists Do Not Disrupt Rodent Prepulse Inhibition: An Improved Side Effect Profile in the Treatment of Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Carina J. Bleickardt


    Full Text Available Parkinson's disease (PD is characterized by loss of dopaminergic neurons in the substantia nigra. Current treatments for PD focus on dopaminergic therapies, including L-dopa and dopamine receptor agonists. However, these treatments induce neuropsychiatric side effects. Psychosis, characterized by delusions and hallucinations, is one of the most serious such side effects. Adenosine A2A receptor antagonism is a nondopaminergic treatment for PD with clinical and preclinical efficacy. The present studies assessed A2A antagonists SCH 412348 and istradefylline in rodent prepulse inhibition (PPI, a model of psychosis. Dopamine receptor agonists pramipexole (0.3–3 mg/kg, pergolide (0.3–3 mg/kg, and apomorphine (0.3–3 mg/kg significantly disrupted PPI; ropinirole (1–30 mg/kg had no effect; L-dopa (100–300 mg/kg disrupted rat but not mouse PPI. SCH 412348 (0.3–3 mg/kg did not disrupt rodent PPI; istradefylline (0.1–1 mg/kg marginally disrupted mouse but not rat PPI. These results suggest that A2A antagonists, unlike dopamine agonists, have an improved neuropsychiatric side effect profile.

  12. Gastrin-releasing peptide receptor antagonist or N-acetylcysteine combined with omeprazol protect against mitochondrial complex II inhibition in a rat model of gastritis. (United States)

    Rezin, Gislaine T; Petronilho, Fabricia C; Araújo, João H; Gonçalves, Cinara L; Daufenbach, Juliana F; Cardoso, Mariane R; Roesler, Rafael; Schwartsmann, Gilberto; Dal-Pizzol, Felipe; Streck, Emilio L


    The pathophysiology of gastritis involves an imbalance between gastric acid attack and mucosal defence. In addition, the gastric mucosal injury results in adenosine triphosphate (ATP) depletion leading to mitochondrial dysfunction. Several studies have shown the association of mitochondrial disorders with gastrointestinal dysfunction. In the present study, we investigated the activity of mitochondrial respiratory chain complexes activity in the stomach of rats with gastritis induced by indomethacin (IDM) and treated with omeprazole (OM), N-acetylcysteine (NAC) and the gastrin-releasing peptide receptor (GRPR) antagonist RC-3095. Adult male Wistar rats were pre-treated for 7 days with OM, NAC, RC-3095, combination of OM plus RC-3095, OM plus NAC and water (control). The animals were then submitted to fasting for 24 hr; IDM was administered. The rats were killed 6 hr later, and the stomachs were used for evaluation of macroscopic damage and respiratory chain activity. Our results showed that complex I and IV activities were not affected by administration of IDM. On the other hand, complex II and III activities were inhibited. In addition, OM plus RC-3095 and OM plus NAC did not reverse complex II activity inhibition. However, the complex III activity inhibition was reversed only with the combined use of OM plus RC-3095 and OM plus NAC. Our results are in agreement with previous studies indicating mitochondrial dysfunction in the pathophysiology of gastrointestinal tract disease and we suggest that GRPR antagonism might be a novel therapeutic strategy in gastritis.

  13. Inhibition of platelet aggregation by AZD6140, a reversible oral P2Y12 receptor antagonist, compared with clopidogrel in patients with acute coronary syndromes

    DEFF Research Database (Denmark)

    Storey, Robert F; Husted, Steen; Harrington, Robert A


    OBJECTIVES: In a substudy of DISPERSE (Dose confIrmation Study assessing anti-Platelet Effects of AZD6140 vs. clopidogRel in non-ST-segment Elevation myocardial infarction)-2, we compared the antiplatelet effects of AZD6140 and clopidogrel and assessed the effects of AZD6140 in clopidogrel......-pretreated patients. BACKGROUND: Clopidogrel, in combination with aspirin, reduces cardiovascular events in patients with acute coronary syndromes (ACS). However, patients with poor inhibition of platelet aggregation with clopidogrel may be less well protected. AZD6140 is a reversible oral P2Y(12) receptor antagonist...... that has been studied in ACS patients in comparison with clopidogrel (DISPERSE-2 study). METHODS: Patients were randomized to receive either AZD6140 90 mg twice a day, AZD6140 180 mg twice a day, or clopidogrel 75 mg once a day for up to 12 weeks in a double-blind, double-dummy design. One...

  14. Identification of a novel antagonist of the ErbB1 receptor capable of inhibiting migration of human glioblastoma cells

    DEFF Research Database (Denmark)

    Staberg, Mikkel; Riemer, Christian; Xu, Ruodan


    BACKGROUND: Receptors of the ErbB family are involved in the development of various cancers, and the inhibition of these receptors represents an attractive therapeutic concept. Upon ligand binding, ErbB receptors become activated as homo- or heterodimers, leading to the activation of downstream...

  15. Nonpeptide tachykinin receptor antagonists. III. SB 235375, a low central nervous system-penetrant, potent and selective neurokinin-3 receptor antagonist, inhibits citric acid-induced cough and airways hyper-reactivity in guinea pigs. (United States)

    Hay, Douglas W P; Giardina, Giuseppe A M; Griswold, Don E; Underwood, David C; Kotzer, Charles J; Bush, Brian; Potts, William; Sandhu, Punam; Lundberg, Dave; Foley, James J; Schmidt, Dulcie B; Martin, Lenox D; Kilian, David; Legos, Jeffrey J; Barone, Frank C; Luttmann, Mark A; Grugni, Mario; Raveglia, Luca F; Sarau, Henry M


    In this report the in vitro and in vivo pharmacological and pharmacokinetic profile of (-)-(S)-N-(alpha-ethylbenzyl)-3-(carboxymethoxy)-2-phenylquinoline-4-carboxamide (SB 235375), a low central nervous system (CNS)-penetrant, human neurokinin-3 (NK-3) receptor (hNK-3R) antagonist, is described. SB 235375 inhibited (125)I-[MePhe(7)]-neurokinin B (NKB) binding to membranes of Chinese hamster ovary (CHO) cells expressing the hNK-3R (CHO-hNK-3R) with a K(i) = 2.2 nM and antagonized competitively NKB-induced Ca(2+) mobilization in human embryonic kidney (HEK) 293 cells expressing the hNK-3R (HEK 293-hNK-3R) with a K(b) = 12 nM. SB 235375 antagonized senktide (NK-3R)-induced contractions in rabbit isolated iris sphincter (pA(2) = 8.1) and guinea pig ileal circular smooth muscles (pA(2) = 8.3). SB 235375 was selective for the hNK-3R compared with hNK-1 (K(i) > 100,000 nM) and hNK-2 receptors (K(i) = 209 nM), and was without effect, at 1 microM, in 68 other receptor, enzyme, and ion channel assays. Intravenous SB 235375 produced a dose-related inhibition of miosis induced by i.v. senktide in the rabbit (ED(50) of 0.56 mg/kg). Intraperitoneal SB 235375 (10-30 mg/kg) inhibited citric acid-induced cough and airways hyper-reactivity in guinea pigs. In mice oral SB 235375 (3-30 mg/kg) was without significant effect on the behavioral responses induced by intracerebral ventricular administration of senktide. Pharmacokinetic evaluation in the mouse and rat revealed that oral SB 235375 was well absorbed systemically but did not effectively cross the blood-brain barrier. The preclinical profile of SB 235375, encompassing high affinity, selectivity, oral activity, and low CNS penetration, suggests that it is an appropriate tool compound to define the pathophysiological roles of the NK-3Rs in the peripheral nervous system.

  16. Chikusetsusaponin IVa Butyl Ester (CS-IVa-Be), a Novel IL6R Antagonist, Inhibits IL6/STAT3 Signaling Pathway and Induces Cancer Cell Apoptosis. (United States)

    Yang, Jie; Qian, Shihui; Cai, Xueting; Lu, Wuguang; Hu, Chunping; Sun, Xiaoyan; Yang, Yang; Yu, Qiang; Gao, S Paul; Cao, Peng


    The activation of IL6/STAT3 signaling is associated with the pathogenesis of many cancers. Agents that suppress IL6/STAT3 signaling have cancer-therapeutic potential. In this study, we found that chikusetsusaponin IVa butyl ester (CS-IVa-Be), a triterpenoid saponin extracted from Acanthopanas gracilistylus W.W.Smith, induced cancer cell apoptosis. CS-IVa-Be inhibited constitutive and IL6-induced STAT3 activation, repressed STAT3 DNA-binding activity, STAT3 nuclear translocation, IL6-induced STAT3 luciferase reporter activity, IL6-induced STAT3-regulated antiapoptosis gene expression in MDA-MB-231 cells, and IL6-induced TF-1 cell proliferation. Surprisingly, CS-IVa-Be inhibited IL6 family cytokines rather than other cytokines induced STAT3 activation. Further studies indicated that CS-IVa-Be is an antagonist of IL6 receptor via directly binding to the IL6Rα with a Kd of 663 ± 74 nmol/L and the GP130 (IL6Rβ) with a Kd of 1,660 ± 243 nmol/L, interfering with the binding of IL6 to IL6R (IL6Rα and GP130) in vitro and in cancer cells. The inhibitory effect of CS-IVa-Be on the IL6-IL6Rα-GP130 interaction was relatively specific as CS-IVa-Be showed higher affinity to IL6Rα than to LIFR (Kd: 4,910 ± 1,240 nmol/L) and LeptinR (Kd: 4,990 ± 915 nmol/L). We next demonstrated that CS-IVa-Be not only directly induced cancer cell apoptosis but also sensitized MDA-MB-231 cells to TRAIL-induced apoptosis via upregulating DR5. Our findings suggest that CS-IVa-Be as a novel IL6R antagonist inhibits IL6/STAT3 signaling pathway and sensitizes the MDA-MB-231 cells to TRAIL-induced cell death. Mol Cancer Ther; 15(6); 1190-200. ©2016 AACR.

  17. Inhibition of human ether-a-go-go-related gene potassium channels by alpha 1-adrenoceptor antagonists prazosin, doxazosin, and terazosin. (United States)

    Thomas, Dierk; Wimmer, Anna-Britt; Wu, Kezhong; Hammerling, Bettina C; Ficker, Eckhard K; Kuryshev, Yuri A; Kiehn, Johann; Katus, Hugo A; Schoels, Wolfgang; Karle, Christoph A


    Human ether-a-go-go-related gene (HERG) potassium channels are expressed in multiple tissues including the heart and adenocarcinomas. In cardiomyocytes, HERG encodes the alpha-subunit underlying the rapid component of the delayed rectifier potassium current, I(Kr), and pharmacological reduction of HERG currents may cause acquired long QT syndrome. In addition, HERG currents have been shown to be involved in the regulation of cell proliferation and apoptosis. Selective alpha 1-adrenoceptor antagonists are commonly used in the treatment of hypertension and benign prostatic hyperplasia. Recently, doxazosin has been associated with an increased risk of heart failure. Moreover, quinazoline-derived alpha 1-inhibitors induce apoptosis in cardiomyocytes and prostate tumor cells independently of alpha1-adrenoceptor blockade. To assess the action of the effects of prazosin, doxazosin, and terazosin on HERG currents, we investigated their acute electrophysiological effects on cloned HERG potassium channels heterologously expressed in Xenopus oocytes and HEK 293 cells.Prazosin, doxazosin, and terazosin blocked HERG currents in Xenopus oocytes with IC(50) values of 10.1, 18.2, and 113.2 microM respectively, whereas the IC(50) values for HERG channel inhibition in human HEK 293 cells were 1.57 microM, 585.1 nM, and 17.7 microM. Detailed biophysical studies revealed that inhibition by the prototype alpha 1-blocker prazosin occurred in closed, open, and inactivated channels. Analysis of the voltage-dependence of block displayed a reduction of inhibition at positive membrane potentials. Frequency-dependence was not observed. Prazosin caused a negative shift in the voltage-dependence of both activation (-3.8 mV) and inactivation (-9.4 mV). The S6 mutations Y652A and F656A partially attenuated (Y652A) or abolished (F656A) HERG current blockade, indicating that prazosin binds to a common drug receptor within the pore-S6 region. In conclusion, this study demonstrates that HERG

  18. Retrovirus-mediated delivery of an IL-4 receptor antagonist inhibits allergic responses in a murine model of asthma

    Institute of Scientific and Technical Information of China (English)


    This work reports the investigation of the effect of airway IL-4RA gene transfer by a recombinant retroviral vector on airway inflammation and airway responsiveness in asthmatic mice. The retrovirus-mediated delivery of IL-4RA to the airways of mice inhibited elevations of airway responsiveness and the development of allergic inflammation in asthmatic mice, and regulated the Th1/Th2 balance in OVA-sensitized and -challenged mouse models. This suggests that gene therapy is a therapeutic option for treating and controlling chronic airway inflammation and asthma symptoms.

  19. Dopamine D2 receptor radiotracers [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride are indistinguishably inhibited by D2 agonists and antagonists ex vivo

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, Patrick N. [Institute of Medical Science, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada)], E-mail:; Kapur, Shitij [Department of Psychiatry, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada); PET Center, Center for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Seeman, Philip [Department of Psychiatry, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada); Department of Pharmacology, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada); Wilson, Alan A. [Department of Psychiatry, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada); PET Center, Center for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada)


    Introduction: In vitro, the dopamine D2 receptor exists in two states, with high and low affinity for agonists. The high-affinity state is the physiologically active state thought to be involved in dopaminergic illnesses such as schizophrenia. The positron emission tomography radiotracer [{sup 11}C](+)-PHNO ([{sup 11}C](+)-4-propyl-3,4,4a,5,6,10b-hexahydro-2H-naphtho[1,2-b][1,4] oxazin-9-o l), being a D2 agonist, should selectively label the high-affinity state at tracer dose and therefore be more susceptible to competition by agonist as compared to the antagonist [{sup 3}H]raclopride, which binds to both affinity states. Methods: We tested this prediction using ex vivo dual-radiotracer experiments in conscious rats. D2 antagonists (haloperidol or clozapine), a partial agonist (aripiprazole), a full agonist [(-)-NPA] or the dopamine-releasing drug amphetamine (AMPH) were administered to rats prior to an intravenous coinjection of [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride. Rats were sacrificed 60 min after radiotracer injection. Striatum, cerebellum and plasma samples were counted for {sup 11}C and {sup 3}H. The specific binding ratio {l_brace}SBR, i.e., [%ID/g (striatum)-%ID/g (cerebellum)]/(%ID/g (cerebellum){r_brace} was used as the outcome measure. Results: In response to D2 antagonists, partial agonist or full agonist, [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride SBRs responded indistinguishably in terms of both ED{sub 50} and Hill slope (e.g., (-)-NPA ED{sub 50} values are 0.027 and 0.023 mg/kg for [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride, respectively). In response to AMPH challenge, [{sup 11}C](+)-PHNO and [{sup 3}H]raclopride SBRs were inhibited to the same degree. Conclusions: We have shown that the SBRs of [{sup 11}C](+)-PHNO- and [{sup 3}H]raclopride do not differ in their response to agonist challenge. These results do not support predictions of the in vivo binding behavior of a D2 agonist radiotracer and cast some doubt on the in vivo

  20. The opioid antagonist, β-funaltrexamine, inhibits lipopolysaccharide-induced neuroinflammation and reduces sickness behavior in mice. (United States)

    Davis, Randall L; Stevens, Craig W; Thomas Curtis, J


    Brain pathologies such as neurodegenerative diseases, infection, traumatic brain injury, and mood disorders produce enormous personal and economic burdens. It is well established that neuroinflammation plays an important role in the etiology and/or manifestation of such disorders. Previously, we discovered that beta-funaltrexamine (β-FNA) inhibits inflammatory signaling in human astrocytes in vitro, resulting in reduced expression of proinflammatory cytokines/chemokines. The present study examines the effects of peripherally administered β-FNA on lipopolysaccharide (LPS)-induced neuroinflammation and sickness behavior in vivo. Adult male C57BL/6J mice were administered β-FNA and were then immediately administered bacterial lipopolysaccharide (LPS). At 24h post-injections, sickness behavior was assessed in an open-field test. Following behavioral analysis plasma and brains were collected. Levels of interleukin-6 (IL-6), interferon-γ inducible protein-10 (CXCL10), and monocyte chemoattractant protein-1 (CCL2) were determined by enzyme-linked immunosorbant assay (ELISA). At 24h post-LPS injection, IL-6, CCL2 and CXCL10 were increased in the plasma, whereas, only CCL2 and CXCL10 were elevated in the brain. β-FNA significantly inhibited LPS-induced CXCL10 and CCL2 expression in brain, but minimally or not at all in the plasma. LPS-induced sickness behavior, as indicated by a reduction in distance moved, was prevented by β-FNA. Overall, CXCL10 expression in the brain was most positively and significantly correlated with sickness behavior; whereas, anxiety-like behavior was most positively and significantly correlated with IL-6 and CCL2 levels in the plasma and levels of CXCL10 and CCL2 in the brain. The reduction in sickness behavior may be in part due to decreased chemokine expression in the brain; further examination of the anti-inflammatory and neuroprotective effects of β-FNA is warranted.

  1. Inhibition of migration and invasion of carcinoma cells by urokinase-derived antagonists of alphavbeta5 integrin activation. (United States)

    Vocca, Immacolata; Franco, Paola; Alfano, Daniela; Votta, Giuseppina; Carriero, Maria Vincenza; Estrada, Yeriel; Caputi, Mario; Netti, Paolo A; Ossowski, Liliana; Stoppelli, Maria Patrizia


    We previously showed that, while binding to urokinase receptor (uPAR) through its growth factor domain (GFD, residues 1-49), urokinase (uPA) can engage alphavbeta5 integrin through an internal domain (CP, residues 132-158). This novel uPA/alphavbeta5 interaction promotes cytoskeletal rearrangements and directional cell migration (Franco et al., J Cell Sci 2006;119:3424-34). We now show that treatment of cells with phosphomimic uPA (uPA138E/303E, serine 138 and 303 substituted with glutamic acid) strongly inhibits matrix-induced cell migration. Unlike uPA, binding of uPA138E/303E to cell surface did not induce F-actin enriched protruding structures and caused a 5-fold reduction in cell translocation speed, as determined by video tracking of living cells. Inhibition of migration was found to be independent of uPAR, since uPA variants lacking the GFD domain, but carrying the relevant Ser to Glu substitutions were as effective inhibitor as uPA138E/303E. Through several independent approaches, we established that the phosphomimics specifically bind to alphavbeta5 integrin through the CP region carrying the S138E mutation. This interaction blocks integrin activation, as determined by a decreased affinity of alphavbeta5 to vitronectin and a reduced association of the beta5 cytoplasmic tail with talin. Finally, stable expression of uPA138E/303E in human squamous carcinoma cells prevented tumor cell invasion in vivo. Thus, when expressed in cancer cells, the inhibitory phosphomimic effect was dominant over the effect of endogenously produced uPA. These results shed light on the regulation of cell migration by uPA phosphorylation and provide a realistic opportunity for a novel antiinvasive/metastatic therapeutic intervention.

  2. Small-molecule RORγt antagonists inhibit T helper 17 cell transcriptional network by divergent mechanisms. (United States)

    Xiao, Sheng; Yosef, Nir; Yang, Jianfei; Wang, Yonghui; Zhou, Ling; Zhu, Chen; Wu, Chuan; Baloglu, Erkan; Schmidt, Darby; Ramesh, Radha; Lobera, Mercedes; Sundrud, Mark S; Tsai, Pei-Yun; Xiang, Zhijun; Wang, Jinsong; Xu, Yan; Lin, Xichen; Kretschmer, Karsten; Rahl, Peter B; Young, Richard A; Zhong, Zhong; Hafler, David A; Regev, Aviv; Ghosh, Shomir; Marson, Alexander; Kuchroo, Vijay K


    We identified three retinoid-related orphan receptor gamma t (RORγt)-specific inhibitors that suppress T helper 17 (Th17) cell responses, including Th17-cell-mediated autoimmune disease. We systemically characterized RORγt binding in the presence and absence of drugs with corresponding whole-genome transcriptome sequencing. RORγt acts as a direct activator of Th17 cell signature genes and a direct repressor of signature genes from other T cell lineages; its strongest transcriptional effects are on cis-regulatory sites containing the RORα binding motif. RORγt is central in a densely interconnected regulatory network that shapes the balance of T cell differentiation. Here, the three inhibitors modulated the RORγt-dependent transcriptional network to varying extents and through distinct mechanisms. Whereas one inhibitor displaced RORγt from its target loci, the other two inhibitors affected transcription predominantly without removing DNA binding. Our work illustrates the power of a system-scale analysis of transcriptional regulation to characterize potential therapeutic compounds that inhibit pathogenic Th17 cells and suppress autoimmunity.

  3. A PAF receptor antagonist inhibits acute airway inflammation and late-phase responses but not chronic airway inflammation and hyperresponsiveness in a primate model of asthma

    Directory of Open Access Journals (Sweden)

    R. H. Gundel


    Full Text Available We have examined the effects of a PAF receptor antagonist, WEB 2170, on several indices of acute and chronic airway inflammation and associated changes in lung function in a primate model of allergic asthma. A single oral administration WEB 2170 provided dose related inhibition of the release of leukotriene C4 (LTC4 and prostaglandin D2 (PGD2 recovered and quantified in bronchoalveolar lavage (BAL fluid obtained during the acute phase response to inhaled antigen. In addition, oral WEB 2170 treatment in dual responder primates blocked the acute influx of neutrophils into the airways as well as the associated late-phase airway obstruction occurring 6 h after antigen inhalation. In contrast, a multiple dosing regime with WEB 2170 (once a day for 7 consecutive days failed to reduce the chronic airway inflammation (eosinophilic and associated airway hyperresponsiveness to inhaled methacholine that is characteristic of dual responder monkeys. Thus, we conclude that the generation of PAF following antigen inhalation contributes to the development of lipid mediators, acute airway inflammation and associated late-phase airway obstruction in dual responder primates; however, PAF does not play a significant role in the maintenance of chronic airway inflammation and associated airway hyperresponsiveness in this primate model.

  4. Serotonin-induced blood flow changes in the rat hindlegs after unilateral ligation of the femoral artery. Inhibition by the S2 receptor antagonist ketanserin. (United States)

    Verheyen, A; Vlaminckx, E; Lauwers, F; Van Den Broeck, C; Wouters, L


    Collateral arteries can clearly be visualized in corrosion cast material after ligation of the femoral artery in rats. To characterize the influence of serotonin on the blood circulation under the experimental condition of unilateral ligation, we performed intermuscular thermoflow measurements. The data showed that intraperitoneal serotonin (8.7 and 20 injection markedly reduced the muscle temperature in both hindlegs. However, the effect was significantly more pronounced on the ligated side, where the blood was supplied through a collateral circulation, than on the non-ligated side with its normal arterial vasculature. Almost identical changes were obtained in rats with an early as well as in animals with a more advanced stage of collateral development (challenge with 8.7 serotonin). Evans blue dye experiments and angiographic data further revealed that, after challenge with 20 serotonin, the severe temperature decrease at the ligated side probably reflected a nearly complete blockage of blood supply. Pretreatment with the S2 receptor antagonist ketanserin (2.5 resulted in a significant reduction in the extent and duration of the serotonin-induced temperature decrease as revealed by the temperature measurements; such a treatment inhibited also the blockage in blood flow as seen with the other techniques. This study shows that serotonin, through its vasoconstrictive properties, can restrict the blood flow to the lower extremities of the rat, particularly when the blood is supplied through collateral circulation. This probably results in moderate to severe skeletal muscle ischaemia. It also suggests that the vasoconstriction is not only important in the inhibition of collateral blood flow in recently established collaterals but also in collateral vessels in a more advanced stage of development. The in vivo vasoconstriction and subsequent reduction of the blood supply caused by serotonin can be effectively counteracted by

  5. A Peptide Antagonist of the ErbB1 Receptor Inhibits Receptor Activation, Tumor Cell Growth and Migration In Vitro and Xenograft Tumor Growth In Vivo

    Directory of Open Access Journals (Sweden)

    Ruodan Xu


    Full Text Available The epidermal growth factor family of receptor tyrosine kinases (ErbBs plays essential roles in tumorigenesis and cancer disease progression, and therefore has become an attractive target for structure-based drug design. ErbB receptors are activated by ligand-induced homo- and heterodimerization. Structural studies have revealed that ErbB receptor dimers are stabilized by receptor–receptor interactions, primarily mediated by a region in the second extracellular domain, termed the “dimerization arm”. The present study is the first biological characterization of a peptide, termed Inherbin3, which constitutes part of the dimerization arm of ErbB3. Inherbin3 binds to the extracellular domains of all four ErbB receptors, with the lowest peptide binding affinity for ErbB4. Inherbin3 functions as an antagonist of epidermal growth factor (EGF-ErbB1 signaling. We show that Inherbin3 inhibits EGF-induced ErbB1 phosphorylation, cell growth, and migration in two human tumor cell lines, A549 and HN5, expressing moderate and high ErbB1 levels, respectively. Furthermore, we show that Inherbin3 inhibits tumor growth in vivo and induces apoptosis in a tumor xenograft model employing the human non-small cell lung cancer cell line A549. The Inherbin3 peptide may be a useful tool for investigating the mechanisms of ErbB receptor homo- and heterodimerization. Moreover, the here described biological effects of Inherbin3 suggest that peptide-based targeting of ErbB receptor dimerization is a promising anti-cancer therapeutic strategy.

  6. CARMIL is a potent capping protein antagonist: identification of a conserved CARMIL domain that inhibits the activity of capping protein and uncaps capped actin filaments. (United States)

    Uruno, Takehito; Remmert, Kirsten; Hammer, John A


    Acanthamoeba CARMIL was previously shown to co-purify with capping protein (CP) and to bind pure CP. Here we show that this interaction inhibits the barbed end-capping activity of CP. Even more strikingly, this interaction drives the uncapping of actin filaments previously capped with CP. These activities are CP-specific; CARMIL does not inhibit the capping activities of either gelsolin or CapG and does not uncap gelsolin-capped filaments. Although full-length (FL) CARMIL (residues 1-1121) possesses both anti-CP activities, C-terminal fragments like glutathione S-transferase (GST)-P (940-1121) that contain the CARMIL CP binding site are at least 10 times more active. We localized the full activities of GST-P to its C-terminal 51 residues (1071-1121). This sequence contains a stretch of 25 residues that is highly conserved in CARMIL proteins from protozoa, flies, worms, and vertebrates (CARMIL Homology domain 3; CAH3). Point mutations showed that the majority of the most highly conserved residues within CAH3 are critical for the anti-CP activity of GST-AP (862-1121). Finally, we found that GST-AP binds CP approximately 20-fold more tightly than does FL-CARMIL. This observation together with the elevated activities of C-terminal fragments relative to FL-CARMIL suggests that FL-CARMIL might exist primarily in an autoinhibited state. Consistent with this idea, proteolytic cleavage of FL-CARMIL with thrombin generated an approximately 14-kDa C-terminal fragment that expresses full anti-CP activities. We propose that, after some type of physiological activation event, FL-CARMIL could function in vivo as a potent CP antagonist. Given the pivotal role that CP plays in determining the global actin phenotype of cells, our results suggest that CARMIL may play an important role in the physiological regulation of actin assembly.

  7. Graft-Infiltrating Macrophages Adopt an M2 Phenotype and Are Inhibited by Purinergic Receptor P2X7 Antagonist in Chronic Rejection. (United States)

    Wu, C; Zhao, Y; Xiao, X; Fan, Y; Kloc, M; Liu, W; Ghobrial, R M; Lan, P; He, X; Li, X C


    Macrophages exhibit diverse phenotypes and functions; they are also a major cell type infiltrating chronically rejected allografts. The exact phenotypes and roles of macrophages in chronic graft loss remain poorly defined. In the present study, we used a mouse heart transplant model to examine macrophages in chronic allograft rejection. We found that treatment of C57BL/6 mice with CTLA4 immunoglobulin fusion protein (CTLA4-Ig) prevented acute rejection of a Balb/c heart allograft but allowed chronic rejection to develop over time, characterized by prominent neointima formation in the graft. There was extensive macrophage infiltration in the chronically rejected allografts, and the graft-infiltrating macrophages expressed markers associated with M2 cells but not M1 cells. In an in vitro system in which macrophages were polarized into either M1 or M2 cells, we screened phenotypic differences between M1 and M2 cells and identified purinergic receptor P2X7 (P2x7r), an adenosine triphosphate (ATP)-gated ion channel protein that was preferentially expressed by M2 cells. We further showed that blocking the P2x7r using oxidized ATP (oATP) inhibited M2 induction in a dose-dependent fashion in vitro. Moreover, treatment of C57BL/6 recipients with the P2x7r antagonist oATP, in addition to CTLA4-Ig treatment, inhibited graft-infiltrating M2 cells, prevented transplant vasculopathy, and induced long-term heart allografts survival. These findings highlight the importance of the P2x7r-M2 axis in chronic rejection and establish P2x7r as a potential therapeutic target in suppression of chronic rejection.

  8. The microbiota maintain homeostasis of liver-resident γδT-17 cells in a lipid antigen/CD1d-dependent manner (United States)

    Li, Fenglei; Hao, Xiaolei; Chen, Yongyan; Bai, Li; Gao, Xiang; Lian, Zhexiong; Wei, Haiming; Sun, Rui; Tian, Zhigang


    The microbiota control regional immunity using mechanisms such as inducing IL-17A-producing γδ T (γδT-17) cells in various tissues. However, little is known regarding hepatic γδT cells that are constantly stimulated by gut commensal microbes. Here we show hepatic γδT cells are liver-resident cells and predominant producers of IL-17A. The microbiota sustain hepatic γδT-17 cell homeostasis, including activation, survival and proliferation. The global commensal quantity affects the number of liver-resident γδT-17 cells; indeed, E. coli alone can generate γδT-17 cells in a dose-dependent manner. Liver-resident γδT-17 cell homeostasis depends on hepatocyte-expressed CD1d, that present lipid antigen, but not Toll-like receptors or IL-1/IL-23 receptor signalling. Supplementing mice in vivo or loading hepatocytes in vitro with exogenous commensal lipid antigens augments the hepatic γδT-17 cell number. Moreover, the microbiota accelerate nonalcoholic fatty liver disease through hepatic γδT-17 cells. Thus, our work describes a unique liver-resident γδT-17 cell subset maintained by gut commensal microbes through CD1d/lipid antigens. PMID:28067223

  9. GABAB antagonists

    DEFF Research Database (Denmark)

    Frydenvang, Karla Andrea; Hansen, J J; Krogsgaard-Larsen, P


    Phaclofen, which is the phosphonic acid analogue of the GABAB agonist (RS)-3-(4-chlorophenyl)-4-aminobutyric acid (baclofen), is a GABAB antagonist. As part of our studies on the structural requirements for activation and blockade of GABAB receptors, we have resolved phaclofen using chiral chroma...

  10. P2Y6 Receptor Antagonist MRS2578 Inhibits Neutrophil Activation and Aggregated Neutrophil Extracellular Trap Formation Induced by Gout-Associated Monosodium Urate Crystals. (United States)

    Sil, Payel; Hayes, Craig P; Reaves, Barbara J; Breen, Patrick; Quinn, Shannon; Sokolove, Jeremy; Rada, Balázs


    Human neutrophils (polymorphonuclear leukocytes [PMNs]) generate inflammatory responses within the joints of gout patients upon encountering monosodium urate (MSU) crystals. Neutrophil extracellular traps (NETs) are found abundantly in the synovial fluid of gout patients. The detailed mechanism of MSU crystal-induced NET formation remains unknown. Our goal was to shed light on possible roles of purinergic signaling and neutrophil migration in mediating NET formation induced by MSU crystals. Interaction of human neutrophils with MSU crystals was evaluated by high-throughput live imaging using confocal microscopy. We quantitated NET levels in gout synovial fluid supernatants and detected enzymatically active neutrophil primary granule enzymes, myeloperoxidase, and human neutrophil elastase. Suramin and PPADS, general P2Y receptor blockers, and MRS2578, an inhibitor of the purinergic P2Y6 receptor, blocked NET formation triggered by MSU crystals. AR-C25118925XX (P2Y2 antagonist) did not inhibit MSU crystal-stimulated NET release. Live imaging of PMNs showed that MRS2578 represses neutrophil migration and blocked characteristic formation of MSU crystal-NET aggregates called aggregated NETs. Interestingly, the store-operated calcium entry channel inhibitor (SK&F96365) also reduced MSU crystal-induced NET release. Our results indicate that the P2Y6/store-operated calcium entry/IL-8 axis is involved in MSU crystal-induced aggregated NET formation, but MRS2578 could have additional effects affecting PMN migration. The work presented in the present study could lead to a better understanding of gouty joint inflammation and help improve the treatment and care of gout patients.

  11. Protein kinase A antagonist inhibits β-catenin nuclear translocation, c-Myc and COX-2 expression and tumor promotion in ApcMin/+ mice

    Directory of Open Access Journals (Sweden)

    Brudvik Kristoffer W


    Full Text Available Abstract Background The adenomatous polyposis coli (APC protein is part of the destruction complex controlling proteosomal degradation of β-catenin and limiting its nuclear translocation, which is thought to play a gate-keeping role in colorectal cancer. The destruction complex is inhibited by Wnt-Frz and prostaglandin E2 (PGE2 - PI-3 kinase pathways. Recent reports show that PGE2-induced phosphorylation of β-catenin by protein kinase A (PKA increases nuclear translocation indicating two mechanisms of action of PGE2 on β-catenin homeostasis. Findings Treatment of ApcMin/+ mice that spontaneously develop intestinal adenomas with a PKA antagonist (Rp-8-Br-cAMPS selectively targeting only the latter pathway reduced tumor load, but not the number of adenomas. Immunohistochemical characterization of intestines from treated and control animals revealed that expression of β-catenin, β-catenin nuclear translocation and expression of the β-catenin target genes c-Myc and COX-2 were significantly down-regulated upon Rp-8-Br-cAMPS treatment. Parallel experiments in a human colon cancer cell line (HCT116 revealed that Rp-8-Br-cAMPS blocked PGE2-induced β-catenin phosphorylation and c-Myc upregulation. Conclusion Based on our findings we suggest that PGE2 act through PKA to promote β-catenin nuclear translocation and tumor development in ApcMin/+ mice in vivo, indicating that the direct regulatory effect of PKA on β-catenin nuclear translocation is operative in intestinal cancer.

  12. Inhibition of Brain Swelling after Ischemia-Reperfusion by β-Adrenergic Antagonists: Correlation with Increased K+ and Decreased Ca2+ Concentrations in Extracellular Fluid

    Directory of Open Access Journals (Sweden)

    Dan Song


    Full Text Available Infarct size and brain edema following ischemia/reperfusion are reduced by inhibitors of the Na+, K+, 2Cl−, and water cotransporter NKCC1 and by β1-adrenoceptor antagonists. NKCC1 is a secondary active transporter, mainly localized in astrocytes, driven by transmembrane Na+/K+ gradients generated by the Na+,K+-ATPase. The astrocytic Na+,K+-ATPase is stimulated by small increases in extracellular K+ concentration and by the β-adrenergic agonist isoproterenol. Larger K+ increases, as occurring during ischemia, also stimulate NKCC1, creating cell swelling. This study showed no edema after 3 hr medial cerebral artery occlusion but pronounced edema after 8 hr reperfusion. The edema was abolished by inhibitors of specifically β1-adrenergic pathways, indicating failure of K+-mediated, but not β1-adrenoceptor-mediated, stimulation of Na+,K+-ATPase/NKCC1 transport during reoxygenation. Ninety percent reduction of extracellular Ca2+ concentration occurs in ischemia. Ca2+ omission abolished K+ uptake in normoxic cultures of astrocytes after addition of 5 mM KCl. A large decrease in ouabain potency on K+ uptake in cultured astrocytes was also demonstrated in Ca2+-depleted media, and endogenous ouabains are needed for astrocytic K+ uptake. Thus, among the ionic changes induced by ischemia, the decrease in extracellular Ca2+ causes failure of the high-K+-stimulated Na+,K+-ATPase/NKCC1 ion/water uptake, making β1-adrenergic activation the only stimulus and its inhibition effective against edema.

  13. The Combination of Marketed Antagonists of α1b-Adrenergic and 5-HT2A Receptors Inhibits Behavioral Sensitization and Preference to Alcohol in Mice: A Promising Approach for the Treatment of Alcohol Dependence.

    Directory of Open Access Journals (Sweden)

    Fabrice Trovero

    Full Text Available Alcohol-dependence is a chronic disease with a dramatic and expensive social impact. Previous studies have indicated that the blockade of two monoaminergic receptors, α1b-adrenergic and 5-HT2A, could inhibit the development of behavioral sensitization to drugs of abuse, a hallmark of drug-seeking and drug-taking behaviors in rodents. Here, in order to develop a potential therapeutic treatment of alcohol dependence in humans, we have blocked these two monoaminergic receptors by a combination of antagonists already approved by Health Agencies. We show that the association of ifenprodil (1 mg/kg and cyproheptadine (1 mg/kg (α1-adrenergic and 5-HT2 receptor antagonists marketed as Vadilex ® and Periactine ® in France, respectively blocks behavioral sensitization to amphetamine in C57Bl6 mice and to alcohol in DBA2 mice. Moreover, this combination of antagonists inhibits alcohol intake in mice habituated to alcohol (10% v/v and reverses their alcohol preference. Finally, in order to verify that the effect of ifenprodil was not due to its anti-NMDA receptors property, we have shown that a combination of prazosin (0.5 mg/kg, an α1b-adrenergic antagonist, Mini-Press ® in France and cyproheptadine (1 mg/kg could also reverse alcohol preference. Altogether these findings strongly suggest that combined prazosin and cyproheptadine could be efficient as a therapy to treat alcoholism in humans. Finally, because α1b-adrenergic and 5-HT2A receptors blockade also inhibits behavioral sensitization to psychostimulants, opioids and tobacco, it cannot be excluded that this combination will exhibit some efficacy in the treatment of addiction to other abused drugs.

  14. Tetrahydroindolizinone NK1 antagonists. (United States)

    Bao, Jianming; Lu, Huagang; Morriello, Gregori J; Carlson, Emma J; Wheeldon, Alan; Chicchi, Gary G; Kurtz, Marc M; Tsao, Kwei-Lan C; Zheng, Song; Tong, Xinchun; Mills, Sander G; DeVita, Robert J


    A new class of potent NK(1) receptor antagonists with a tetrahydroindolizinone core has been identified. This series of compounds demonstrated improved functional activities as compared to previously identified 5,5-fused pyrrolidine lead structures. SAR at the 7-position of the tetrahydroindolizinone core is discussed in detail. A number of compounds displayed high NK(1) receptor occupancy at both 1 h and 24 h in a gerbil foot tapping model. Compound 40 has high NK(1) binding affinity, good selectivity for other NK receptors and promising in vivo properties. It also has clean P(450) inhibition and hPXR induction profiles.


    Institute of Scientific and Technical Information of China (English)

    PENGDun-Ren; XIAOShao-Bo


    An ideal antagonist of LHRH is one which can act on the pitutary to inhibit LHRH-stimulatod LH / FSH secretion by competitive occupying the LHRH receptor in the pitutary gland. Its action should be very specific, fast and highly effective, the durations

  16. Benzodiazepine receptor antagonists for hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Gluud, L L; Gluud, C


    Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy....

  17. Angiotensin II type 2 receptor (AT2R) localization and antagonist-mediated inhibition of capsaicin responses and neurite outgrowth in human and rat sensory neurons


    Anand, U; Facer, P; Yiangou, Y.; Sinisi, M; Fox, M.; McCarthy, T.; Bountra, C; Korchev, YE; Anand, P


    Background The angiotensin II (AngII) receptor subtype 2 (AT2R) is expressed in sensory neurons and may play a role in nociception and neuronal regeneration. Methods We used immunostaining with characterized antibodies to study the localization of AT2R in cultured human and rat dorsal root ganglion (DRG) neurons and a range of human tissues. The effects of AngII and AT2R antagonist EMA401 on capsaicin responses in cultured human and rat (DRG) neurons were measured with calcium imaging, on neu...

  18. 致病疫霉拮抗细菌的筛选及抑菌作用研究%Screening of Antagonistic Bacterial Strain against Phytophthora infestans and Its Inhibition Effect

    Institute of Scientific and Technical Information of China (English)

    李丽艳; 蒋继志; 郭文


    [Objective] The paper was to screen bacterial strain with significant antagonistic effect against Phytophthora infestans, so as to provide basis for further development and utilization of antagonistic bacteria to control P. infestans and potato late bright. [ Method] Plant confrontation and filter paper method was used to determine the inhibition effect of living, fermentation product, and bacterial fluid of 61 strains a-gainst P. infestans and the induced resistance of SR13-2 strain. [Result] The inhibition rate of 24 strains among 61 tested strains against my-celial growth of P. infestans was greater than 60% , and the inhibition effect of HT-6 strain was the strongest with the inhibition rate of 89.92%. However, fermentation product of all tested strains had no significant inhibition effect on P. infestans, while the inhibition effect of bacterial fluid of most strains was significantly higher than living strain; the inhibition effect of S34-1 strain was the strongest with inhibition rate of 91.50%. The bacterial fluid of SR13-2 strain was found to have significant resistance-induction effect with protection rate of 60%. [Conclusion] The inhibition effect of living and fermentation product of antagonistic strains S34-1 and SR13-2 had no relationship with each other, while bacterial fluid had great potential in controlling potato late bright.%[目的]筛选获得显著拮抗致病疫霉的细菌菌株,为深入开发利用拮抗细菌抑制致病疫霉并控制马铃薯晚疫病提供依据.[方法]用平板对峙法和滤纸片法测定61株细菌活体、发酵液及茵液对致病疫霉的抑制作用并进一步测定了SR13-2菌株的诱导抗病作用.[结果]供试的61株细菌活体对致病疫霉菌丝生长的抑制率达到60%以上的有24株,其中HT-6菌株的抑茵作用最强,抑茵率达到了89.92%:但所有供试菌株的发酵液均无显著抑菌作用,而大部分菌株茵液的抑茵作用却明显高于活体菌株,其中以S34-1菌

  19. FAAH inhibitor, URB-597, promotes extinction and CB(1) antagonist, SR141716, inhibits extinction of conditioned aversion produced by naloxone-precipitated morphine withdrawal, but not extinction of conditioned preference produced by morphine in rats. (United States)

    Manwell, Laurie A; Satvat, Elham; Lang, Stefan T; Allen, Craig P; Leri, Francesco; Parker, Linda A


    Converging evidence suggests that the endogenous cannabinoid (eCB) system is involved in extinction of learned behaviours. Using operant and classical conditioning procedures, the potential of the fatty acid amide (FAAH) inhibitor, URB-597, and the CB(1) antagonist/inverse agonist, SR141716, to promote and inhibit (respectively) extinction of learned responses previously motivated by either rewarding or aversive stimuli was investigated. In the operant conditioning procedure (Expt. 1), rats previously trained to lever press for sucrose reward were administered URB-597 (0.3 mg/kg) or the CB(1) antagonist/inverse agonist SR141716 (2.5 mg/kg) prior to each of three extinction trials. In the conditioned floor preference procedure (Expts 2a-d), rats trained to associate morphine with one of two distinctive floors were administered one of several doses of the CB(1) antagonist/inverse agonist, AM-251 (Expt 2a) or URB-597 (Expt 2b and 2d) prior to each extinction/test trial wherein a choice of both floors was presented and prior to forced exposure to each floor (Expt 2c). In the conditioned floor aversion procedure (Expt. 3), rats trained to associate a naloxone-precipitated morphine withdrawal with a floor cue were administered URB-597 or SR141716 prior to each of 24 extinction/testing trials. URB-597 did not promote and SR141716 did not reduce extinction rates for sucrose reward-induced operant responding (Expt. 1) or morphine-induced conditioned floor preference (Expts. 2a-d). In contrast, URB-597 facilitated, whereas SR141716 impaired, extinction of the conditioned floor aversion (Expt. 3). These data support previous reports that the eCB system selectively facilitates extinction of aversive memories. URB-597 may prove useful in targeting extinction of aversively motivated behaviours.

  20. A potent and selective calcitonin gene-related peptide (CGRP) receptor antagonist, MK-8825, inhibits responses to nociceptive trigeminal activation: Role of CGRP in orofacial pain. (United States)

    Romero-Reyes, Marcela; Pardi, Vanessa; Akerman, Simon


    Temporomandibular disorders (TMDs) are orofacial pains within the trigeminal distribution, which involve the masticatory musculature, the temporomandibular joint or both. Their pathophysiology remains unclear, as inflammatory mediators are thought to be involved, and clinically TMD presents pain and sometimes limitation of function, but often appears without gross indications of local inflammation, such as visible edema, redness and increase in temperature. Calcitonin gene-related peptide (CGRP) has been implicated in other pain disorders with trigeminal distribution, such as migraine, of which TMD shares a significant co-morbidity. CGRP causes activation and sensitization of trigeminal primary afferent neurons, independent of any inflammatory mechanisms, and thus may also be involved in TMD. Here we used a small molecule, selective CGRP receptor antagonist, MK-8825, to dissect the role of CGRP in inducing spontaneous nociceptive facial grooming behaviors, neuronal activation in the trigeminal nucleus, and systemic release of pro-inflammatory cytokines, in a mouse model of acute orofacial masseteric muscle pain that we have developed, as a surrogate of acute TMD. We show that CFA masseteric injection causes significant spontaneous orofacial pain behaviors, neuronal activation in the trigeminal nucleus, and release of interleukin-6 (IL-6). In mice pre-treated with MK-8825 there is a significant reduction in these spontaneous orofacial pain behaviors. Also, at 2 and 24h after CFA injection the level of Fos immunoreactivity in the trigeminal nucleus, used as a marker of neuronal activation, was much lower on both ipsilateral and contralateral sides after pre-treatment with MK-8825. There was no effect of MK-8825 on the release of IL-6. These data suggest that CGRP may be involved in TMD pathophysiology, but not via inflammatory mechanisms, at least in the acute stage. Furthermore, CGRP receptor antagonists may have therapeutic efficacy in the treatment of TMD, as they

  1. Expression of gastrin-releasing peptide is increased by prolonged stretch of human myometrium, and antagonists of its receptor inhibit contractility. (United States)

    Tattersall, Mark; Cordeaux, Yolande; Charnock-Jones, D Stephen; Smith, Gordon C S


    Increased uterine stretch appears to increase the risk of preterm labour, but the mechanism is unknown. The aim of this study was to identify factors that mediate the effect of stretch on human myometrium.Myometrial explants, prepared from biopsies obtained at elective caesarean delivery, were either studied acutely, or were maintained in prolonged culture (up to 65 h) under tension with either a 0.6 g or a 2.4 g mass, and compared using in vitro contractility, whole genome array, and qRT-PCR. Tissue held at tonic stretch with the 2.4 g mass for either 24 or 65 h showed increased potassium chloride (KCl)-induced and oxytocin-induced contractility compared with that held with the 0.6 g mass. Gene array identified 62 differentially expressed transcripts after 65 h exposure to increased stretch. Two probes for gastrin-releasing peptide (GRP), a known stimulatory agonist of smooth muscle, were among the top five up-regulated by stretch (3.4-fold and 2.0-fold). Up-regulation of GRP mRNA by stretch was confirmed in a separate series of 10 samples using quantitative RT-PCR (qRT-PCR) (2.8-fold, P =0.01). GRP stimulated contractions acutely when added to freshly obtained myometrial strips in 2 out of 9 cases, but Western blot demonstrated expression of the GRP receptor in 9 out of a further 9 cases. Prolonged incubation of stretched explants in the GRP antagonists PD-176252 or RC-3095 (65 and 24 h, respectively) significantly reduced KCl- and oxytocin-induced contractility.Tonic stretch of human myometrium increases contractility and stimulates the expression of a known smooth muscle stimulatory agonist, GRP. Incubation of myometrium with GRP receptor antagonists attenuates the effect of stretch. GRP may be a target for novel therapies to reduce the risk of preterm birth in multiple pregnancy.

  2. Porphyrin analogues as novel antagonists of fibroblast growth factor and vascular endothelial growth factor receptor binding that inhibit endothelial cell proliferation, tumor progression, and metastasis. (United States)

    Aviezer, D; Cotton, S; David, M; Segev, A; Khaselev, N; Galili, N; Gross, Z; Yayon, A


    Fibroblast growth factors (FGFs) and vascular endothelial growth factor (VEGF) play a pivotal role in the multistep pathway of tumor progression, metastasis, and angiogenesis. We have identified a porphyrin analogue, 5,10,15,20-tetrakis(methyl-4-pyridyl)-21H,23H-porphine-tetra -p-tosylate salt (TMPP), as a potent inhibitor of FGF2 and VEGF receptor binding and activation. TMPP demonstrated potent inhibition of binding of soluble FGF receptor 1 (FGFR1) to FGF2 immobilized on heparin at submicromolar concentrations. TMPP inhibits binding of radiolabeled FGF2 to FGFR in a cell-free system as well as to cells genetically engineered to express FGFR1. Furthermore, TMPP also inhibits the binding of VEGF to its tyrosine kinase receptor in a dose-dependent manner. In an in vitro angiogenic assay measuring the extent of endothelial cell growth, tube formation, and sprouting, TMPP dramatically reduced the extent of the FGF2-induced endothelial cell outgrowth and differentiation. In a Lewis lung carcinoma model, mice receiving TMPP showed a marked inhibition of both primary tumor progression and lung metastases development, with nearly total inhibition of the metastatic phenotype upon alternate daily injections of TMPP at 25 microg/g of body mass. Finally, novel meso-pyridylium-substituted, nonsymmetric porphyrins, as well as a novel corrole-based derivative, with >50-fold increase in activity in vitro, had a significantly improved efficacy in blocking tumor progression and metastasis in vivo.

  3. Isolation and Identification of Antagonistic Streptomyces spp. Against Fusarium Wilt of Watermelon and Primarily Potted Inhibition Test%西瓜枯萎病拮抗链霉菌分离鉴定及盆栽抗病试验

    Institute of Scientific and Technical Information of China (English)

    任迁琪; 宋星林; 吴洪生; 李季; 陈素云; 徐亚; 姚东良; 赵月; 陈健; 李美颖


    旨在筛选出能高效抑制西瓜枯萎病病原菌尖孢镰刀菌(Fusarium oxysporum f. sp. niveum)的天然拮抗菌。采用梯度稀释法分离连作辣椒根际土中的放线菌,纯化后用平板对峙法筛选出有拮抗作用的菌株,采用盆钵育苗基质拌菌法接种,进行盆栽抗病试验,并对拮抗效果最佳的菌株进行鉴定。结果显示,从连作辣椒根际土中,分离筛选出10株对西瓜枯萎病有拮抗作用的放线菌,其中菌株 F22、F23、F32的拮抗作用显著。96 h 抑菌圈直径分别达到1.70、1.17和1.47 cm。盆栽试验结果表明,拮抗菌株 F32对西瓜枯萎病30 d 的防治效果最佳,防效率达到66.7%,且抗菌谱性广。根据表型特征、生理生化特性和16S rDNA 分子鉴定结果可知,菌株 F32为链霉菌属(Streptomyces sp.),且对西瓜枯萎病有良好的防治作用,是一株具有应用价值的生防菌株。%The objective is to select a natural antagonistic bacterium efficiently controlling Fusarium oxysporum f. sp. niveum that is the pathogenic bacterium of the fusarium wilt of watermelon. Using the method of gradient dilution to isolate actinomycetes from rhizosphere soil of continuous cropping pepper,it was purified and the plate confrontation method was applied to select an antagonistic strain. Then the method of basin nursery substrates mixed with bacteria was for inoculation,a potted plant disease-resistant experiment was carried out,and the strains with the optimal antagonistic effects were identified. The results showed that 10 strains of actinomycetes with the antagonistic effects to fusarium wilt of watermelon were isolated from the growing pepper rhizosphere soil,and 3 of them(F22,F23 and F32)presented the significantly antagonistic effects. After 96 hours the diameter of the inhibition zone was 1.70 cm,1.17 cm and 1.47 cm respectively. The result of the potted plant experiments demonstrated that the control effect of the

  4. Glutamate antagonists limit tumor growth



    Neuronal progenitors and tumor cells possess propensity to proliferate and to migrate. Glutamate regulates proliferation and migration of neurons during development, but it is not known whether it influences proliferation and migration of tumor cells. We demonstrate that glutamate antagonists inhibit proliferation of human tumor cells. Colon adenocarcinoma, astrocytoma, and breast and lung carcinoma cells were most sensitive to the antiproliferative effect of the N...

  5. Low-dose combination of Rho kinase and L-type Ca(2+) channel antagonists for selective inhibition of depolarization-induced sustained arterial contraction. (United States)

    Porras-González, Cristina; González-Rodríguez, Patricia; Calderón-Sánchez, Eva; López-Barneo, José; Ureña, Juan


    L-type Ca(2+) channels (LTCCs) are involved in the maintenance of tonic arterial contractions and regulate the RhoA/Rho-associated kinase (ROCK) sensitization cascade. We have tested effects of individual and combined low concentrations of LTCCs and ROCK inhibitors to produce arterial relaxation without the adverse side effects of LTCCs antagonists. We have also studied whether this pharmacological strategy alters Ca(2+)-dependent electrical properties of isolated arterial and cardiac myocytes as well as cardiac contractility. Rat basilar, human carotid and coronary arterial rings were mounted on a small-vessel myograph to measure isometric tension and cardiac contractility was measured in Langendorff-perfused rat heart. Simultaneous cytosolic Ca(2+) concentration and arterial diameter were measured in intact pressurized arteries loaded with Fura-2. Patch-clamp techniques were used to measure electrical properties in isolated cardiac and arterial myocytes. Low concentrations of LTCCs and ROCK inhibitors reduced the tonic component of moderate depolarization-evoked contraction, leaving the phasic component practically unaltered. This selective vasorelaxant effect was more marked when the LTCCs and ROCK inhibitors were applied together. In the concentration range used (nM), Ca(2+) currents in arterial myocytes, cardiac action potentials and heart contractility were unaffected by this pharmacological approach. In conclusion, low doses of LTCCs and ROCK inhibitors could be used to selectively relax precontracted arteries in pathologic conditions such as hypertension, and cerebral or coronary spasms with minor side effects on physiological contractile properties of vascular and cardiac myocytes.

  6. Sigma-1 Receptor Antagonist BD1047 Reduces Mechanical Allodynia in a Rat Model of Bone Cancer Pain through the Inhibition of Spinal NR1 Phosphorylation and Microglia Activation. (United States)

    Zhu, Shanshan; Wang, Chenchen; Han, Yuan; Song, Chao; Hu, Xueming; Liu, Yannan


    Previous studies have demonstrated that sigma-1 receptor plays important roles in the induction phase of rodent neuropathic pain; however, whether it is involved in bone cancer pain (BCP) and the underlying mechanisms remain elusive. The aim of this study was to examine the potential role of the spinal sigma-1 receptor in the development of bone cancer pain. Walker 256 mammary gland carcinoma cells were implanted into the intramedullary space of the right tibia of Sprague-Dawley rats to induce ongoing bone cancer-related pain behaviors; our findings indicated that, on days 7, 10, 14, and 21 after operation, the expression of sigma-1 receptor in the spinal cord was higher in BCP rats compared to the sham rats. Furthermore, intrathecal injection of 120 nmol of sigma-1 receptor antagonist BD1047 on days 5, 6, and 7 after operation attenuated mechanical allodynia as well as the associated induction of c-Fos and activation of microglial cells, NR1, and the subsequent Ca(2+)-dependent signals of BCP rats. These results suggest that sigma-1 receptor is involved in the development of bone cancer pain and that targeting sigma-1 receptor may be a new strategy for the treatment of bone cancer pain.

  7. Prolonged Oral Administration of a Pan-Retinoic Acid Receptor Antagonist Inhibits Spermatogenesis in Mice With a Rapid Recovery and Changes in the Expression of Influx and Efflux Transporters. (United States)

    Chung, Sanny S W; Wang, Xiangyuan; Wolgemuth, Debra J


    We have previously shown that oral administration of a pan-retinoic acid receptor antagonist in mice daily at 2.5 mg/kg for 4 weeks reversibly inhibited spermatogenesis, with no detectable side effects. To elucidate the lowest dose and the longest dosing regimen that inhibits spermatogenesis but results in complete restoration of fertility upon cessation of administration of the drug, we examined the effects of daily doses as low as 1.0 mg/kg with dosing periods of 4, 8, and 16 weeks. We observed 100% sterility in all regimens, with restoration of fertility upon cessation of the drug treatment even for as long as 16 weeks. There was no change in testosterone levels in these males and the progeny examined from 2 of the recovered males were healthy and fertile, with normal testicular weight and testicular histology. Strikingly, a more rapid recovery, as assessed by mating studies, was observed at the lower dose and longer dosing periods. Insight into possible mechanisms underlying this rapid recovery was obtained at 2 levels. First, histological examination revealed that spermatogenesis was not as severely disrupted at the lower dose and with the longer treatment regimens. Second, gene expression analysis revealed that the more rapid recovery may involve the interplay of ATP-binding cassette efflux and solute carrier influx transporters in the testes.

  8. 烟草根黑腐病拮抗内生细菌的筛选及其抑菌作用%Inhibition effect and screening of antagonistic endophytic bacteria against Thielaviopsis basicola

    Institute of Scientific and Technical Information of China (English)

    易龙; 马冠华; 肖崇刚


    [目的]从烟草根、茎中分离获得对烟草根黑腐病菌(Thielaviopsis basicola)有较好控病作用的内生细菌.[方法]采用平板对峙培养,测定分离获得的306个内生细菌对烟草根黑腐病菌的抑制作用;通过菌株形态特征、生理生化特性及16S rDNA序列对菌株进行分类鉴定.[结果]筛选获得6个菌株对烟草根黑腐病菌有较强拮抗作用,室内测定其对病原菌的抑菌带宽达6.5 mm-11.0 mm,温室控病效果达11.9%-77.1%,其中来自茎部的内生细菌T295菌株对烟草根黑腐病的防效达77.1%;无菌滤液实验表明,拮抗内生细菌T295无菌滤液在实验浓度范围内对病菌菌丝生长、孢子萌发有较好地抑制作用.[结论]菌株T295对烟草根黑腐病具有较好的防治作用,经鉴定为枯草芽孢杆菌(Bacillus subtilis).%[Objective] Screening the antagonistic endophytic bacteria against Thielaviopsis basicola from inner of tobacco roots and stems collected from Chongqing.[Methods] The antagonistic effect of 306 endophytic bacteria against Thielaviopsis basicola by pairing culture on PDA plates, the strain was identified by morphological, physiological and biochemical characteristics, and homology analysis of the partial sequence of 16S rDNA.[Results] Six endophytic bacteria were showed high antagonistic effect against Thielaviopsis basicola, the pathogen of tobacco black root rot.The inhibition zone diameters were ranged from 6.5 mm to 11.0 mm by pairing culture on PDA plates, and the control efficacy ranged from 11.9% to 77.1% in a greenhouse experiment.It was found that strain T295 could reduce the incidence of tobacco black root rot, the control efficacy reaching to 77.1%, and the culture filtrate of strain T295 could inhibit hyphal growth and reduce spore germination of T.basicola.[Conclusion] Strain T295 had a good antagonistic effect on Thielaviopsis basicola, was identified as Bacillus subtilis.

  9. A peptide antagonist of the ErbB1 receptor inhibits receptor activation, tumor cell growth and migration in vitro and xenograft tumor growth in vivo

    DEFF Research Database (Denmark)

    Xu, Ruodan; Povlsen, Gro Klitgaard; Soroka, Vladislav


    B1 phosphorylation, cell growth, and migration in two human tumor cell lines, A549 and HN5, expressing moderate and high ErbB1 levels, respectively. Furthermore, we show that Inherbin3 inhibits tumor growth in vivo and induces apoptosis in a tumor xenograft model employing the human non-small cell...... lung cancer cell line A549. The Inherbin3 peptide may be a useful tool for investigating the mechanisms of ErbB receptor homo- and heterodimerization. Moreover, the here described biological effects of Inherbin3 suggest that peptide-based targeting of ErbB receptor dimerization is a promising anti...

  10. An antagonist of the platelet-activating factor receptor inhibits adherence of both nontypeable Haemophilus influenzae and Streptococcus pneumoniae to cultured human bronchial epithelial cells exposed to cigarette smoke

    Directory of Open Access Journals (Sweden)

    Shukla SD


    cells. In silico analyses identified a binding pocket for PAF/WEB-2086 in the predicted PAFr structure.Conclusion: WEB-2086 represents an innovative class of candidate drugs for inhibiting PAFr-dependent lung infections caused by the main bacterial drivers of smoking-related COPD. Keywords: airway epithelium, NTHi, pneumococci, WEB-2086, platelet-activating factor receptor, PAFr antagonist

  11. Screening of antagonistic actinomycetic strains and their inhibitions against Phytophthora in festans%致病疫霉拮抗放线菌的筛选及抑菌作用初步研究

    Institute of Scientific and Technical Information of China (English)

    刘月; 蒋继志; 郭俊亭; 郭文; 李丽艳


    为获得对致病疫霉具有显著且稳定拮抗作用的放线菌,利用对峙培养法和滤纸片法测定了从土壤中分离纯化出的放线菌活体及其发酵液对致病疫霉生长的抑制作用,并对其中抑菌效果显著的Sy11菌株的抑菌方式、对致病疫霉的感应性、传代稳定性以及对致病疫霉菌体形态的影响进行了初步研究.结果表明,分离纯化出的74株放线菌中有17株对致病疫霉具有拮抗作用,但其发酵液对致病疫霉均无抑制作用;Sy11菌株只有感应到致病疫霉存在时才分泌对致病疫霉的抑菌物质;连续传代25次后,Sy11菌株的抑制率仍然保持在81%以上;Sy11菌株可导致致病疫霉菌丝体严重变形,但只是抑制其生长,并未杀死致病疫霉.这些结果表明,Sy11菌株在防治马铃薯晚疫病方面具有较大的应用潜力.%In order to obtain highly effective and stably antagonistic actinomycetes strains a-gainst Phytophthora infestans, the inhibitory effects of living and fermentation filtrates of actinomycetic strains isolated from vegetable-grown soil on mycelial growth of P. infestans were detected with dual-culture and filter paper methods, and inhibitory manner, response to P. infestans, stability of inhibition effect after continuous passage culture, and influence on P. infestans mycelial morphological character were investigated in this experiment. The results showed that 17 of 74 strains were evidently antagonistic to P. infestans, but all of fermentation liquors of 17 strains were not antagonistic to P. infestans. Syll strain had response to P. infestans, and could produce and secrete some substances inhibiting P. infestans. After continuous passage culture for 25 times, the inhibitory rate of Syll strain on P. infestans still maintained over 81%. Syll strain could cause to lose original sketch and structure seriously. However, Syll strain just inhibited P. infestans but did not kill it. These results indicated

  12. Viral Inhibition of the IFN-Induced JAK/STAT Signalling Pathway: Development of Live Attenuated Vaccines by Mutation of Viral-Encoded IFN-Antagonists

    Directory of Open Access Journals (Sweden)

    Stephen B. Fleming


    Full Text Available The interferon (IFN induced anti-viral response is amongst the earliest and most potent of the innate responses to fight viral infection. The induction of the Janus kinase/signal transducer and activation of transcription (JAK/STAT signalling pathway by IFNs leads to the upregulation of hundreds of interferon stimulated genes (ISGs for which, many have the ability to rapidly kill viruses within infected cells. During the long course of evolution, viruses have evolved an extraordinary range of strategies to counteract the host immune responses in particular by targeting the JAK/STAT signalling pathway. Understanding how the IFN system is inhibited has provided critical insights into viral virulence and pathogenesis. Moreover, identification of factors encoded by viruses that modulate the JAK/STAT pathway has opened up opportunities to create new anti-viral drugs and rationally attenuated new generation vaccines, particularly for RNA viruses, by reverse genetics.

  13. 番茄灰霉病内生拮抗菌的筛选及抑菌物质研究%Screening of Endophytic Antagonistic Bacteria and It's Inhibitive Substance to Control Tomato Gray Mold

    Institute of Scientific and Technical Information of China (English)

    张根伟; 张丽萍; 李书生; 程辉彩


    [ Objective ] The aim was to screen endophytic antagonistic bacteria and study it' s inhibitive substance to control tomato gray mold. [Method] Forty-six endophytic antagonistic bacteria strains were isolated from 65 healthy tomato plants which had antimicrobial activity to control tomato gray mold, and one strain which could produce antimicrobial substances was screened out by using PDA well-diffusion method. The inhibition of antimicrobial substances to mycelium and spores of Botrytis cinerea was studied, and the antimicrobial substances was i-dentified through acid precipitation, Sephadex G-50 gel chromatography and agarose gel electrophoresis analysis primarily. [ Result] It was observed under microscope that the antibacterial substances had the mechanism of tearing cell membrane. The antimicrobial substances was identified as 3. 3 kDa of proteins or polypeptide primarily. [ Conclusion] The research result provides reference for the development of new biocon-trol preparation.%[目的]筛选番茄灰霉病内生拮抗菌并研究其抑菌物质.[方法]从65株健康番茄植株中分离到内生拮抗细菌46株,在此基础上通过PDA培养基打孔扩散法进行复筛,获得了1株强烈抑制灰葡萄孢菌的抑菌物质产生菌.研究了该抑菌物质对灰葡萄孢菌菌丝和孢子的抑制作用,并经酸沉淀、Sephadex G-50凝胶层析纯化、琼脂糖凝胶电泳分析对其进行了初步鉴定.[结果]显微镜观察发现该抑菌物质具有列膜抑菌机制,初步鉴定抗菌物质为3.3 kDa左右的多肽类物质.[结论]为开发新的生防制剂奠定了基础.

  14. The Ape-1/Ref-1 redox antagonist E3330 inhibits the growth of tumor endothelium and endothelial progenitor cells: therapeutic implications in tumor angiogenesis. (United States)

    Zou, Gang-Ming; Karikari, Collins; Kabe, Yasuaki; Handa, Hiroshi; Anders, Robert A; Maitra, Anirban


    The apurinic/apyrimidinic endonuclease 1/redox factor-1 (Ape-1/Ref-1) is a multi-functional protein, involved in DNA repair and the activation of redox-sensitive transcription factors. The Ape-1/Ref-1 redox domain acts as a cytoprotective element in normal endothelial cells, mitigating the deleterious effects of apoptotic stimuli through induction of survival signals. We explored the role of the Ape-1/Ref-1 redox domain in the maintenance of tumor-associated endothelium, and of endothelial progenitor cells (EPCs), which contribute to tumor angiogenesis. We demonstrate that E3330, a small molecule inhibitor of the Ape-1/Ref-1 redox domain, blocks the in vitro growth of pancreatic cancer-associated endothelial cells (PCECs) and EPCs, which is recapitulated by stable expression of a dominant-negative redox domain mutant. Further, E3330 blocks the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) into CD31(+) endothelial progeny. Exposure of PCECs to E3330 results in a reduction of H-ras expression and intracellular nitric oxide (NO) levels, as well as decreased DNA-binding activity of the hypoxia-inducible transcription factor, HIF-1alpha. E3330 also reduces secreted and intracellular vascular endothelial growth factor expression by pancreatic cancer cells, while concomitantly downregulating the cognate receptor Flk-1/KDR on PCECs. Inhibition of the Ape-1/Ref-1 redox domain with E3330 or comparable angiogenesis inhibitors might be a potent therapeutic strategy in solid tumors.

  15. Antioxidant effects of calcium antagonists in rat brain homogenates. (United States)

    Yao, K; Ina, Y; Nagashima, K; Ohmori, K; Ohno, T


    We studied the antioxidant activities of calcium antagonists against autoxidation in rat brain homogenates. The homogenates were incubated for 30 min at 37 degrees C with or without a calcium antagonist and subsequently assayed for lipid peroxide content. Percent inhibition of the lipid peroxidation was used as an index of the antioxidant effect. Dihydropyridine calcium antagonists exhibited concentration-dependent (3-300 micromol/l) inhibitory effects against lipid peroxidation. The relative order of antioxidant potency and associated IC50 values (micromol/l) of the calcium antagonists for inhibition of the lipid peroxidation were as follows: nifedipine (51.5)>barnidipine (58.6)>benidipine (71.2)>nicardipine (129.3)>amlodipine (135.5)>nilvadipine (167.3)>nitrendipine (252.1)> diltiazem (>300)=verapamil (>300). These results suggest that some dihydropyridine calcium antagonists show antioxidant properties. The antioxidant effects of the calcium antagonists may contribute to their pharmacological actions.

  16. From the Cover: Glutamate antagonists limit tumor growth (United States)

    Rzeski, Wojciech; Turski, Lechoslaw; Ikonomidou, Chrysanthy


    Neuronal progenitors and tumor cells possess propensity to proliferate and to migrate. Glutamate regulates proliferation and migration of neurons during development, but it is not known whether it influences proliferation and migration of tumor cells. We demonstrate that glutamate antagonists inhibit proliferation of human tumor cells. Colon adenocarcinoma, astrocytoma, and breast and lung carcinoma cells were most sensitive to the antiproliferative effect of the N-methyl-D-aspartate antagonist dizocilpine, whereas breast and lung carcinoma, colon adenocarcinoma, and neuroblastoma cells responded most favorably to the -amino-3-hydroxy-5-methyl-4-isoxazole-propionate antagonist GYKI52466. The antiproliferative effect of glutamate antagonists was Ca2+ dependent and resulted from decreased cell division and increased cell death. Morphological alterations induced by glutamate antagonists in tumor cells consisted of reduced membrane ruffling and pseudopodial protrusions. Furthermore, glutamate antagonists decreased motility and invasive growth of tumor cells. These findings suggest anticancer potential of glutamate antagonists.

  17. Why are mineralocorticoid receptor antagonists cardioprotective?

    NARCIS (Netherlands)

    W. Chai (Wenxia); A.H.J. Danser (Jan)


    textabstractTwo clinical trials, the Randomized ALdosterone Evaluation Study (RALES) and the EPlerenone HEart failure and SUrvival Study (EPHESUS), have recently shown that mineralocorticoid receptor (MR) antagonists reduce mortality in patients with heart failure on top of ACE inhibition. This effe

  18. Inhibition of SNL-induced upregulation of CGRP and NPY in the spinal cord and dorsal root ganglia by the 5-HT(2A) receptor antagonist ketanserin in rats. (United States)

    Wang, Dongmei; Chen, Tingjun; Gao, Yun; Quirion, Rémi; Hong, Yanguo


    Our previous study has demonstrated that topical and systemic administration of the 5-HT(2A) receptor antagonist ketanserin attenuates neuropathic pain. To explore the mechanisms involved, we examined whether ketanserin reversed the plasticity changes associated with calcitonin gene-related peptides (CGRP) and neuropeptide Y (NPY) which may reflect distinct mechanisms: involvement and compensatory protection. Behavioral responses to thermal and tactile stimuli after spinal nerve ligation (SNL) at L5 demonstrated neuropathic pain and its attenuation in the vehicle- and ketanserin-treated groups, respectively. SNL surgery induced an increase in CGRP and NPY immunoreactivity (IR) in laminae I-II of the spinal cord. L5 SNL produced an expression of NPY-IR in large, medium and small diameter neurons in dorsal root ganglion (DRG) only at L5, but not adjacent L4 and L6. Daily injection of ketanserin (0.3 mg/kg, s.c.) for two weeks suppressed the increase in CGRP-IR and NPY-IR in the spinal cord or DRG. The present study demonstrated that: (1) the expression of CGRP was enhanced in the spinal dorsal horn and NPY was expressed in the DRG containing injured neurons, but not in the adjacent DRG containing intact neurons, following L5 SNL; (2) the maladaptive changes in CGRP and NPY expression in the spinal cord and DRG mediated the bioactivity of 5-HT/5-HT(2A) receptors in neuropathic pain and (3) the blockade of 5-HT(2A) receptors by ketanserin reversed the evoked upregulation of both CGRP and NPY in the spinal cord and DRG contributing to the inhibition of neuropathic pain.

  19. Opioid Antagonist Impedes Exposure. (United States)

    Merluzzi, Thomas V.; And Others


    Thirty spider-phobic adults underwent exposure to 17 phobic-related, graded performance tests. Fifteen subjects were assigned to naltrexone, an opioid antagonist, and 15 were assigned to placebo. Naltrexone had a significant effect on exposure, with naltrexone subjects taking significantly longer to complete first 10 steps of exposure and with…

  20. GABAA receptor partial agonists and antagonists

    DEFF Research Database (Denmark)

    Krall, Jacob; Balle, Thomas; Krogsgaard-Larsen, Niels;


    A high degree of structural heterogeneity of the GABAA receptors (GABAARs) has been revealed and is reflected in multiple receptor subtypes. The subunit composition of GABAAR subtypes is believed to determine their localization relative to the synapses and adapt their functional properties...... to the local temporal pattern of GABA impact, enabling phasic or tonic inhibition. Specific GABAAR antagonists are essential tools for physiological and pharmacological elucidation of the different type of GABAAR inhibition. However, distinct selectivity among the receptor subtypes (populations) has been shown...

  1. Inhibition Effect of Antagonist Yeasts on Postharvest Green Mold (Penicillum digitatum) of Shatangju Mandarin%拮抗酵母菌对沙糖桔采后绿霉病的抑制作用

    Institute of Scientific and Technical Information of China (English)

    黄雪梅; 汪跃华; 徐兰英; 庞学群; 张昭其


    The effects of 4 yeasts, Rhodotorula glutinis, Debaryomyces hansenii, Pichia membranaefaciens and Rhodotorula rubra, on the control of green mold (Penicillum digitatum ) were evaluated on harvested Citrus reticulata cv. ‘Shatangju’ fruit, by culturing both the yeast and the pathogen in nutrient yeast dextros agar (NYDB) suspension, and then inoculating the fruit with the cultures. Results showed that P. membranaefaciens and R. rubra apparently inhibited the germination and growth of P. digitatum spores. Adding 2%of NaHCO3 significantly increased the inhibitory effect of P. membranaefaciens while adding 2% of CaCl2 slightly enhanced the effect of R. rubra. The inoculation of fruit with these yeast preparations increased the chitinase activity in fruit peel The best inhibitory effect was the combination of P. membranaefaciens with 2%NaHCO3.The results suggested that P. membranaefaciens and R. rubra could be used as antagonists against postharvest Shatangju fruit rot, and that NaHCO3 was suitable as an active ingredient in commercial yeast preparations for its remarkably activating effect on chitinase which was thought to play an important role in combating fungus diseases in plants.%采用在NYDB上共培养酵母菌与绿霉菌Penicillium digitatum孢子、酵母菌防御接种沙糖桔果实后,挑战接种绿霉菌孢子的方法,研究了几株酵母菌对沙糖桔采后绿霉病的控制效果.结果表明,膜醭毕赤酵母Pichia membranae faciens Hansen和深红酵母Rhodotorula rubra Demme Lodder显著抑制绿霉菌孢子萌发和芽管生长,有效减少沙糖桔绿霉病发生率及病斑数;添加2%NaHCO3可增强膜醭毕赤酵母的抗病效果,添加2%CaCl2对深红酵母的抗病效果有轻微的增强作用.4个拮抗剂组合均能提高沙糖桔果皮几丁质酶活性,以添加2%NaHCO3的拮抗菌制剂的几丁质酶活性最高.膜醭毕赤酵母和深红酵母可作为防治沙糖桔采后病害的拮抗菌,NaHCO3适合作为膜醭

  2. Cannabinoid receptor-1 antagonist inhibits morphine tolerance in rats with inflammatory pain%大麻素受体-1拮抗剂抑制炎性痛大鼠的吗啡耐受效应

    Institute of Scientific and Technical Information of China (English)

    郭茜; 贾丽洁; 王来; 贾辰飞; 薛庆生; 于布为


    Objective To observe changes of cannabinoid receptor-1 (CB1) protein expression in spinal dorsal horn of morphine tolerant rats with inflammatory pain so as to explore the effect of CB1 antagonist in the process of morphine tolerance. Methods Forty male adult Sprague-Dawley rats with intrathecal catheters implanted successfully were randomly divided into four groups(n = 10). In control group, 100 μL normal saline were injected by right metapodium and 3 days later 10 μL saline were given again. In CFA group, 100 μL complete Freund adjuvant (CFA) were injected by right metapodium and 3 days later 10 uL saline were given. In Mor group, 100 μL CFA were injected by right metapodium and 3 days later 10 μg/μL morphine were given. In AM251 group, 100 μL CFA were injected by right metapodium and 3 days later 10 μg morphine and 5 nmol(10 μL) AM251 were given for 7 d. Then the rats were sacrificed at the 8th day. Heat hyperalgesia was evaluated by paw withdrawal thermal latency (PWTL). The expression of CB1 in spinal L2 — L4 was detected by Western blotting. Results The PWTL after CFA administration were significantly lower than before CFA administration in the CFA group, Mor group and AM251 group (all P0.05). The PWTL in Mor group was significantly higher than that in CFA group 1, 2,3 and 5 d after CFA administration (all P0.05). The PWTL in the AM251 group maintained at a high level on day 1, 3, 5, and 7 after CFA administration and the differences of PWTL at each time point were not statistically significant (all P>0.05). The expression of CB1 in Mor group was significantly higher than those in control group (P<0.001) and CFA group (P<0.05) after development of morphine tolerance. Conclusion CB1 antagonist AM251 can inhibit the development of morphine tolerance.%目的 观察吗啡对炎性痛治疗时产生耐受效应的模型大鼠脊髓背角大麻素受体-1(CB1)蛋白表达变化,探讨CB1受体拮抗剂(AM251)对炎性痛大鼠吗啡耐

  3. Predictions of in vivo prolactin levels from in vitro k I values of d 2 receptor antagonists using an agonist-antagonist interaction model

    NARCIS (Netherlands)

    Petersson, K.J.; Vermeulen, A.M.J.; Friberg, L.E.


    Prolactin elevation is a side effect of all currently available D2 receptor antagonists used in the treatment of schizophrenia. Prolactin elevation is the result of a direct antagonistic D2 effect blocking the tonic inhibition of prolactin release by dopamine. The aims of this work were to assess th

  4. Tumor vasculature is regulated by FGF/FGFR signaling-mediated angiogenesis and bone marrow-derived cell recruitment: this mechanism is inhibited by SSR128129E, the first allosteric antagonist of FGFRs. (United States)

    Fons, Pierre; Gueguen-Dorbes, Geneviève; Herault, Jean-Pascal; Geronimi, Fabien; Tuyaret, Joël; Frédérique, Dol; Schaeffer, Paul; Volle-Challier, Cécile; Herbert, Jean-Marc; Bono, Françoise


    Tumor angiogenesis is accompanied by vasculogenesis, which is involved in the differentiation and mobilization of human bone marrow cells. In order to further characterize the role of vasculogenesis in the tumor growth process, the effects of FGF2 on the differentiation of human bone marrow AC133(+) cells (BM-AC133(+)) into vascular precursors were studied in vitro. FGF2, like VEGFA, induced progenitor cell differentiation into cell types with endothelial cell characteristics. SSR128129E, a newly discovered specific FGFR antagonist acting by allosteric interaction with FGFR, abrogated FGF2-induced endothelial cell differentiation, showing that FGFR signaling is essential during this process. To assess the involvement of the FGF/FRGR signaling in vivo, the pre-clinical model of Lewis lung carcinoma (LL2) in mice was used. Subcutaneous injection of LL2 cells into mice induced an increase of circulating EPCs from peripheral blood associated with tumor growth and an increase of intra-tumoral vascular index. Treatment with the FGFR antagonist SSR128129E strongly decreased LL2 tumor growth as well as the intra-tumoral vascular index (41% and 50% decrease vs. vehicle-treated mice respectively, P FGFR pathway by SSR128129E reduces EPC recruitment during angiogenesis-dependent tumor growth. In this context, circulating EPCs could be a reliable surrogate marker for tumor growth and angiogenic activity.

  5. Structure-based drug design identifies novel LPA3 antagonists. (United States)

    Fells, James I; Tsukahara, Ryoko; Liu, Jianxiong; Tigyi, Gabor; Parrill, Abby L


    Compound 5 ([5-(3-nitrophenoxy)-1,3-dioxo-1,3-dihydro-2-isoindol-2-yl]acetic acid) was identified as a weak selective LPA(3) antagonist (IC(50)=4504 nM) in a virtual screening effort to optimize a dual LPA(2 and 3) antagonist. Structure-based drug design techniques were used to prioritize similarity search matches of compound 5. This strategy rapidly identified 10 novel antagonists. The two most efficacious compounds identified inhibit activation of the LPA(3) receptor by 200 nM LPA with IC(50) values of 752 nM and 2992 nM. These compounds additionally define changes to our previously reported pharmacophore that will improve its ability to identify more potent and selective LPA(3) receptor antagonists. The results of the combined computational and experimental screening are reported.

  6. A novel antagonistic role of natural compound icariin on neurotoxicity of amyloid β peptide

    Directory of Open Access Journals (Sweden)

    Jianhui Liu


    Interpretation & conclusions: The results indicated a novel antagonistic role of icariin in the neurotoxicity of Aβ1-42 via inhibiting its aggregation, suggesting that icariin might have potential therapeutic benefits to delay or modify the progression of AD.

  7. Selection of Antagonistic Bacteria against Citrus Green Mold and Its Inhibition Activity on Shatang Mandarin Fruit%柑桔绿霉病拮抗细菌的筛选、鉴定及其抑制效果

    Institute of Scientific and Technical Information of China (English)

    郝卫宁; 李辉; 胡美英; 耿鹏; 杨柳


    A bacterial strain HC-03, isolated from rhizosphere soil of citrus fanns, exhibited extensive antagonistic effect on 12 fruit pathogens. The strain was identified as Bacillus amyloliquefaciens based on 16S rDNA sequence homology, specific PCR detection, physiological and biochemical characteristics and morphological observation. Effect of different treatments of strain HC-03 against disease caused by Penicillium digitatum on inoculated shatang mandarin was also investigated. Results showed that citrus green mold incidence of shatang mandarin treated by cell culture, cell-free filtrate and cell suspension of strain HC-03 were all less than 20%, and lesion diameter were all below 10 mm.%从采集的柑桔园根际土壤中筛选得到1株对柑桔绿霉菌Penicillium digitatum具有较强拮抗活性的菌株HC-03.该菌株对柑桔绿霉菌、柑桔青霉菌Penicillium italicum、柑桔酸腐菌Geotrichum candidum等12种水果病原菌均有不同程度的拮抗作用,表现出广谱抗菌活性.菌落形态观察、生理生化特性分析及16S rDNA 序列测定和特异性PCR检测结果表明,该菌株为解淀粉芽孢杆菌Bacillus amyloliquefaciens.对沙糖桔的活体接种试验表明,菌株HC-03的发酵液、菌悬液及发酵滤液处理柑桔绿霉病的发生率均低于20%,病斑直径均在10mm以下.

  8. Zebrafish phenotypic screen identifies novel Notch antagonists. (United States)

    Velaithan, Vithya; Okuda, Kazuhide Shaun; Ng, Mei Fong; Samat, Norazwana; Leong, Sze Wei; Faudzi, Siti Munirah Mohd; Abas, Faridah; Shaari, Khozirah; Cheong, Sok Ching; Tan, Pei Jean; Patel, Vyomesh


    Zebrafish represents a powerful in vivo model for phenotype-based drug discovery to identify clinically relevant small molecules. By utilizing this model, we evaluated natural product derived compounds that could potentially modulate Notch signaling that is important in both zebrafish embryogenesis and pathogenic in human cancers. A total of 234 compounds were screened using zebrafish embryos and 3 were identified to be conferring phenotypic alterations similar to embryos treated with known Notch inhibitors. Subsequent secondary screens using HEK293T cells overexpressing truncated Notch1 (HEK293TΔE) identified 2 compounds, EDD3 and 3H4MB, to be potential Notch antagonists. Both compounds reduced protein expression of NOTCH1, Notch intracellular domain (NICD) and hairy and enhancer of split-1 (HES1) in HEK293TΔE and downregulated Notch target genes. Importantly, EDD3 treatment of human oral cancer cell lines demonstrated reduction of Notch target proteins and genes. EDD3 also inhibited proliferation and induced G0/G1 cell cycle arrest of ORL-150 cells through inducing p27(KIP1). Our data demonstrates the utility of the zebrafish phenotypic screen and identifying EDD3 as a promising Notch antagonist for further development as a novel therapeutic agent.

  9. Exploration of a new series of PAR1 antagonists. (United States)

    Planty, Bruno; Pujol, Chantal; Lamothe, Marie; Maraval, Catherine; Horn, Clemens; Le Grand, Bruno; Perez, Michel


    Two series of new PAR1 antagonists have been identified. The first incorporates a cinnamoylpiperidine motif and the second a cinnamoylpyridine pattern. The synthesis, biological activity and structure-activity relationship of these compounds are presented. In each series, one analog showed potent in vivo antithrombotic activity in a rat AV shunt model, with up to 53% inhibition at 1.25mpk iv for compound 30.

  10. Synthesis of potential mescaline antagonists. (United States)

    DeSantis, F; Nieforth, K A


    1-[2-(3,4,5-Trimethoxyphenyl)ethyl]-3-pyrroline, 2-(3,4,5-trimethoxybenzyl)-1,2,3,6-tetrahydropyridine, N-n-propylmescaline, N-cyclopropylmethylmescaline, and N-allylmescaline were synthesized as potential mescaline antagonists. The ability of these compounds to antagonize mescaline-induced disruption of swim behavior is also given.

  11. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B


    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation......)-phenylethylamine salt of N-BOC-(R)-ATAA. Like ATAA, neither (R)- nor (S)-ATAA significantly affected (IC50 > 100 microM) the receptor binding of tritiated AMPA, kainic acid, or (RS)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, the latter being a competitive NMDA antagonist. Electrophysiological experiments......, using the rat cortical wedge preparation, showed the NMDA antagonist effect as well as the AMPA antagonist effect of ATAA to reside exclusively in the (R)-enantiomer (Ki = 75 +/- 5 microM and 57 +/- 1 microM, respectively). Neither (R)- nor (S)-ATAA significantly reduced kainic acid-induced excitation...

  12. Twisted gastrulation, a BMP antagonist, exacerbates podocyte injury.

    Directory of Open Access Journals (Sweden)

    Sachiko Yamada

    Full Text Available Podocyte injury is the first step in the progression of glomerulosclerosis. Previous studies have demonstrated the beneficial effect of bone morphogenetic protein 7 (Bmp7 in podocyte injury and the existence of native Bmp signaling in podocytes. Local activity of Bmp7 is controlled by cell-type specific Bmp antagonists, which inhibit the binding of Bmp7 to its receptors. Here we show that the product of Twisted gastrulation (Twsg1, a Bmp antagonist, is the central negative regulator of Bmp function in podocytes and that Twsg1 null mice are resistant to podocyte injury. Twsg1 was the most abundant Bmp antagonist in murine cultured podocytes. The administration of Bmp induced podocyte differentiation through Smad signaling, whereas the simultaneous administration of Twsg1 antagonized the effect. The administration of Bmp also inhibited podocyte proliferation, whereas simultaneous administration of Twsg1 antagonized the effect. Twsg1 was expressed in the glomerular parietal cells (PECs and distal nephron of the healthy kidney, and additionally in damaged glomerular cells in a murine model of podocyte injury. Twsg1 null mice exhibited milder hypoalbuminemia and hyperlipidemia, and milder histological changes while maintaining the expression of podocyte markers during podocyte injury model. Taken together, our results show that Twsg1 plays a critical role in the modulation of protective action of Bmp7 on podocytes, and that inhibition of Twsg1 is a promising means of development of novel treatment for podocyte injury.

  13. Effects of ionotropic glutamate receptor antagonists on rat dural artery diameter in an intravital microscopy model

    DEFF Research Database (Denmark)

    Chan, K Y; Gupta, S; de Vries, R;


    studies have shown that glutamate receptor antagonists affect the pathophysiology of migraine. This study investigated whether antagonists of NMDA (ketamine and MK801), AMPA (GYKI52466) and kainate (LY466195) glutamate receptors affected dural vasodilatation induced by alpha-CGRP, capsaicin......During migraine, trigeminal nerves may release calcitonin gene-related peptide (CGRP), inducing cranial vasodilatation and central nociception; hence, trigeminal inhibition or blockade of craniovascular CGRP receptors may prevent this vasodilatation and abort migraine headache. Several preclinical...

  14. Biological Control of Chickpea Collar Rot by Co-inoculation of Antagonistic Bacteria and Compatible Rhizobia


    Hameeda, B.; Harini, G.; Rupela, O. P.; Kumar Rao, J. V. D. K.; Reddy, Gopal


    Two hundred and seven bacteria were isolated from composts and macrofauna and screened for plant growth promoting and antagonistic traits. Seven of the 207 isolates showed antagonistic activity against Sclerotium rolfsii in plate culture. Inhibition of S. rolfsii by the bacterial isolates ranged between 61 and 84%. Two of the seven isolates were Bacillus sp. and rest belonged to Pseudomonas sp. Two isolates, Pseudomonas sp. CDB 35 and Pseudomonas sp. BWB 21 was compatible with chickpea Rhizob...

  15. The Effect of Antagonist Muscle Sensory Input on Force Regulation.

    Directory of Open Access Journals (Sweden)

    Tanya Onushko

    Full Text Available The purpose of this study was to understand how stretch-related sensory feedback from an antagonist muscle affects agonist muscle output at different contraction levels in healthy adults. Ten young (25.3 ± 2.4 years, healthy subjects performed constant isometric knee flexion contractions (agonist at 6 torque levels: 5%, 10%, 15%, 20%, 30%, and 40% of their maximal voluntary contraction. For half of the trials, subjects received patellar tendon taps (antagonist sensory feedback during the contraction. We compared error in targeted knee flexion torque and hamstring muscle activity, with and without patellar tendon tapping, across the 6 torque levels. At lower torque levels (5%, 10%, and 15%, subjects produced greater knee torque error following tendon tapping compared with the same torque levels without tendon tapping. In contrast, we did not find any difference in torque output at higher target levels (20%, 30%, and 40% between trials with and without tendon tapping. We also observed a load-dependent increase in the magnitude of agonist muscle activity after tendon taps, with no associated load-dependent increase in agonist and antagonist co-activation, or reflex inhibition from the antagonist tapping. The findings suggest that at relatively low muscle activity there is a deficiency in the ability to correct motor output after sensory disturbances, and cortical centers (versus sub-cortical are likely involved.

  16. Characterization of a novel non-steroidal glucocorticoid receptor antagonist

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qun-Yi; Zhang, Meng [The National Center for Drug Screening, Shanghai (China); State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China); Hallis, Tina M.; DeRosier, Therese A. [Cell Systems Division, Invitrogen, Madison, WI (United States); Yue, Jian-Min; Ye, Yang [State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China); Mais, Dale E. [The National Center for Drug Screening, Shanghai (China); MPI Research, Mattawan, MI (United States); Wang, Ming-Wei, E-mail: [The National Center for Drug Screening, Shanghai (China); State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China)


    Selective antagonists of the glucocorticoid receptor (GR) are desirable for the treatment of hypercortisolemia associated with Cushing's syndrome, psychic depression, obesity, diabetes, neurodegenerative diseases, and glaucoma. NC3327, a non-steroidal small molecule with potent binding affinity to GR (K{sub i} = 13.2 nM), was identified in a high-throughput screening effort. As a full GR antagonist, NC3327 greatly inhibits the dexamethasone (Dex) induction of marker genes involved in hepatic gluconeogenesis, but has a minimal effect on matrix metalloproteinase 9 (MMP-9), a GR responsive pro-inflammatory gene. Interestingly, the compound recruits neither coactivators nor corepressors to the GR complex but competes with glucocorticoids for the interaction between GR and a coactivator peptide. Moreover, NC3327 does not trigger GR nuclear translocation, but significantly blocks Dex-induced GR transportation to the nucleus, and thus appears to be a 'competitive' GR antagonist. Therefore, the non-steroidal compound, NC3327, may represent a new class of GR antagonists as potential therapeutics for a variety of cortisol-related endocrine disorders.

  17. Aryl biphenyl-3-ylmethylpiperazines as 5-HT7 receptor antagonists. (United States)

    Kim, Jeeyeon; Kim, Youngjae; Tae, Jinsung; Yeom, Miyoung; Moon, Bongjin; Huang, Xi-Ping; Roth, Bryan L; Lee, Kangho; Rhim, Hyewhon; Choo, Il Han; Chong, Youhoon; Keum, Gyochang; Nam, Ghilsoo; Choo, Hyunah


    The 5-HT7 receptor (5-HT7 R) is a promising therapeutic target for the treatment of depression and neuropathic pain. The 5-HT7 R antagonist SB-269970 exhibited antidepressant-like activity, whereas systemic administration of the 5-HT7 R agonist AS-19 significantly inhibited mechanical hypersensitivity and thermal hyperalgesia. In our efforts to discover selective 5-HT7 R antagonists or agonists, aryl biphenyl-3-ylmethylpiperazines were designed, synthesized, and biologically evaluated against the 5-HT7 R. Among the synthesized compounds, 1-([2'-methoxy-(1,1'-biphenyl)-3-yl]methyl)-4-(2-methoxyphenyl)piperazine (28) was the best binder to the 5-HT7 R (pKi =7.83), and its antagonistic property was confirmed by functional assays. The selectivity profile of compound 28 was also recorded for the 5-HT7 R over other serotonin receptor subtypes, such as 5-HT1 R, 5-HT2 R, 5-HT3 R, and 5-HT6 R. In a molecular modeling study, the 2-methoxyphenyl moiety attached to the piperazine ring of compound 28 was proposed to be essential for the antagonistic function.

  18. Antagonistic activity of marine sponges associated Actinobacteria

    Institute of Scientific and Technical Information of China (English)

    Selvakumar Dharmaraj; Dhevendaran Kandasamy


    Objective: To focus on the isolation and preliminary characterization of marine sponges associated Actinobacteria particularly Streptomyces species and also their antagonistic activities against bacterial and fungal pathogens. Methods: The sponges were collected from Kovalam and Vizhinjam port of south-west coast of Kerala, India. Isolation of strains was carried out from sponge extracts using international Streptomyces project media. For preliminary identification of the strains, morphological (mycelial colouration, soluble pigments, melanoid pigmentation, spore morphology), nutritional uptake (carbon utilisation, amonoacids influence, sodium chloride tolerance), physiological (pH, temperature) and chemotaxonomical characterization were done. Antimicrobial studies were also carried out for the selected strains. Results: With the help of the spicule structures, the collected marine sponges were identified as Callyspongia diffusa, Mycale mytilorum, Tedania anhelans and Dysidea fragilis. Nearly 94 strains were primarily isolated from these sponges and further they were sub-cultured using international Streptomyces project media. The strains exhibited different mycelial colouration (aerial and substrate), soluble and melanoid pigmentations. The strains possessed three types of sporophore morphology namely rectus flexibilis, spiral and retinaculiaperti. Among the 94 isolates, seven exhibited antibacterial and antifungal activities with maximal zone of inhibition of 30 mm. The nutritional, physiological and chemotaxonomical characteristic study helped in the conventional identification of the seven strains and they all suggest that the strains to be grouped under the genus Streptomyces. Conclusions: The present study clearly helps in the preliminary identification of the isolates associated with marine sponges. Antagonistic activities prove the production of antimicrobial metabolites against the pathogens. Marine sponges associated Streptomyces are universally well

  19. Antarlides: A New Type of Androgen Receptor (AR) Antagonist that Overcomes Resistance to AR-Targeted Therapy. (United States)

    Saito, Shun; Fujimaki, Takahiro; Panbangred, Watanalai; Igarashi, Yasuhiro; Imoto, Masaya


    Prostate cancer is treated with androgen receptor (AR) antagonists but most patients experience disease progression after long-term treatment with these compounds. Therefore, new AR antagonists are required for patient follow-up treatment. In the course of screening for a new AR antagonist, we isolated the novel compounds antarlides A-E (1-5) from Streptomyces sp. BB47. Antarlides are mutually isomeric with respect to the double bond and have a 22-membered-ring macrocyclic structure. The full stereostructure of 1 was established by chemical modifications, including methanolysis, the Trost method, acetonide formation, and the PGME method. 1-5 inhibited the binding of androgen to ARs in vitro. In addition, 2 inhibited the transcriptional activity of not only wild-type AR but also mutant ARs, which are seen in patients with acquired resistance to clinically used AR antagonists. Therefore, antarlides are a potent new generation of AR antagonists that overcome resistance.

  20. μ Opioid receptor: novel antagonists and structural modeling (United States)

    Kaserer, Teresa; Lantero, Aquilino; Schmidhammer, Helmut; Spetea, Mariana; Schuster, Daniela


    The μ opioid receptor (MOR) is a prominent member of the G protein-coupled receptor family and the molecular target of morphine and other opioid drugs. Despite the long tradition of MOR-targeting drugs, still little is known about the ligand-receptor interactions and structure-function relationships underlying the distinct biological effects upon receptor activation or inhibition. With the resolved crystal structure of the β-funaltrexamine-MOR complex, we aimed at the discovery of novel agonists and antagonists using virtual screening tools, i.e. docking, pharmacophore- and shape-based modeling. We suggest important molecular interactions, which active molecules share and distinguish agonists and antagonists. These results allowed for the generation of theoretically validated in silico workflows that were employed for prospective virtual screening. Out of 18 virtual hits evaluated in in vitro pharmacological assays, three displayed antagonist activity and the most active compound significantly inhibited morphine-induced antinociception. The new identified chemotypes hold promise for further development into neurochemical tools for studying the MOR or as potential therapeutic lead candidates.

  1. Muscarinic Receptor Agonists and Antagonists

    Directory of Open Access Journals (Sweden)

    David R. Kelly


    Full Text Available A comprehensive review of pharmacological and medical aspects of the muscarinic class of acetylcholine agonists and antagonists is presented. The therapeutic benefits of achieving receptor subtype selectivity are outlined and applications in the treatment of Alzheimer’s disease are discussed. A selection of chemical routes are described, which illustrate contemporary methodology for the synthesis of chiral medicinal compounds (asymmetric synthesis, chiral pool, enzymes. Routes to bicyclic intrannular amines and intramolecular Diels-Alder reactions are highlighted.

  2. Anti-idiotypic antibody: A new strategy for the development of a growth hormone receptor antagonist. (United States)

    Lan, Hainan; Zheng, Xin; Khan, Muhammad Akram; Li, Steven


    In general, traditional growth hormone receptor antagonist can be divided into two major classes: growth hormone (GH) analogues and anti-growth hormone receptor (GHR) antibodies. Herein, we tried to explore a new class of growth hormone receptor (GHR) antagonist that may have potential advantages over the traditional antagonists. For this, we developed a monoclonal anti-idiotypic antibody growth hormone, termed CG-86. A series of experiments were conducted to characterize and evaluate this antibody, and the results from a competitive receptor-binding assay, Enzyme Linked Immunosorbent Assays (ELISA) and epitope mapping demonstrate that CG-86 behaved as a typical Ab2β. Next, we examined its antagonistic activity using in vitro cell models, and the results showed that CG-86 could effectively inhibit growth hormone receptor-mediated signalling and effectively inhibit growth hormone-induced Ba/F3-GHR638 proliferation. In summary, these studies show that an anti-idiotypic antibody (CG-86) has promise as a novel growth hormone receptor antagonist. Furthermore, the current findings also suggest that anti-idiotypic antibody may represent a novel strategy to produce a new class of growth hormone receptor antagonist, and this strategy may be applied with other cytokines or growth factors.

  3. Antagonistic Neural Networks Underlying Differentiated Leadership Roles

    Directory of Open Access Journals (Sweden)

    Richard Eleftherios Boyatzis


    Full Text Available The emergence of two distinct leadership roles, the task leader and the socio-emotional leader, has been documented in the leadership literature since the 1950’s. Recent research in neuroscience suggests that the division between task oriented and socio-emotional oriented roles derives from a fundamental feature of our neurobiology: an antagonistic relationship between two large-scale cortical networks -- the Task Positive Network (TPN and the Default Mode Network (DMN. Neural activity in TPN tends to inhibit activity in the DMN, and vice versa. The TPN is important for problem solving, focusing of attention, making decisions, and control of action. The DMN plays a central role in emotional self-awareness, social cognition, and ethical decision making. It is also strongly linked to creativity and openness to new ideas. Because activation of the TPN tends to suppress activity in the DMN, an over-emphasis on task oriented leadership may prove deleterious to social and emotional aspects of leadership. Similarly, an overemphasis on the DMN would result in difficulty focusing attention, making decisions and solving known problems. In this paper, we will review major streams of theory and research on leadership roles in the context of recent findings from neuroscience and psychology. We conclude by suggesting that emerging research challenges the assumption that role differentiation is both natural and necessary, in particular when openness to new ideas, people, emotions, and ethical concerns are important to success.

  4. Similarities and Distinctions in Actions of Surface-Directed and Classic Androgen Receptor Antagonists.

    Directory of Open Access Journals (Sweden)

    Ji Ho Suh

    Full Text Available The androgen receptor (AR surface-directed antagonist MJC13 inhibits AR function and proliferation of prostate cancer (PC cells. These effects are related to arrest of an AR/chaperone complex in the cytoplasm. Here, we compared MJC13 and classic AR antagonists such as flutamide and bicalutamide. Microarray analysis and confirmatory qRT-PCR reveals that MJC13 and flutamide inhibit dihydrotestosterone (DHT-dependent genes in LNCaP PC cells. Both compounds are equally effective on a genome wide basis and as effective as second generation AR antagonists (MDV3100, ARN-509 at selected genes. MJC13 inhibits AR binding to the prostate specific antigen (PSA promoter more strongly than flutamide, consistent with different mechanisms of action. Examination of efficacy of MJC13 in conditions that reflect aspects castrate resistant prostate cancer (CRPC reveals that it inhibits flutamide activation of an AR mutant (ART877A that emerges during flutamide withdrawal syndrome, but displays greatly restricted gene-specific activity in 22Rv1 cells that express a constitutively active truncated AR and is inactive against glucocorticoid receptor (GR, which can co-opt androgen-dependent signaling networks in CRPC. Importantly, MJC13 inhibits AR interactions with SRC2 and β-catenin in the nucleus and, unlike flutamide, strongly inhibits amplification of AR activity obtained with transfected SRC2 and β-catenin. MJC13 also inhibits DHT and β-catenin-enhanced cell division in LNCaP cells. Thus, a surface-directed antagonist can block AR activity in some conditions in which a classic antagonist fails and may display utility in particular forms of CRPC.

  5. Similarities and Distinctions in Actions of Surface-Directed and Classic Androgen Receptor Antagonists. (United States)

    Suh, Ji Ho; Chattopadhyay, Arundhati; Sieglaff, Douglas H; Storer Samaniego, Cheryl; Cox, Marc B; Webb, Paul


    The androgen receptor (AR) surface-directed antagonist MJC13 inhibits AR function and proliferation of prostate cancer (PC) cells. These effects are related to arrest of an AR/chaperone complex in the cytoplasm. Here, we compared MJC13 and classic AR antagonists such as flutamide and bicalutamide. Microarray analysis and confirmatory qRT-PCR reveals that MJC13 and flutamide inhibit dihydrotestosterone (DHT)-dependent genes in LNCaP PC cells. Both compounds are equally effective on a genome wide basis and as effective as second generation AR antagonists (MDV3100, ARN-509) at selected genes. MJC13 inhibits AR binding to the prostate specific antigen (PSA) promoter more strongly than flutamide, consistent with different mechanisms of action. Examination of efficacy of MJC13 in conditions that reflect aspects castrate resistant prostate cancer (CRPC) reveals that it inhibits flutamide activation of an AR mutant (ART877A) that emerges during flutamide withdrawal syndrome, but displays greatly restricted gene-specific activity in 22Rv1 cells that express a constitutively active truncated AR and is inactive against glucocorticoid receptor (GR), which can co-opt androgen-dependent signaling networks in CRPC. Importantly, MJC13 inhibits AR interactions with SRC2 and β-catenin in the nucleus and, unlike flutamide, strongly inhibits amplification of AR activity obtained with transfected SRC2 and β-catenin. MJC13 also inhibits DHT and β-catenin-enhanced cell division in LNCaP cells. Thus, a surface-directed antagonist can block AR activity in some conditions in which a classic antagonist fails and may display utility in particular forms of CRPC.

  6. Effects of calmodulin antagonists on radiation-induced lipid peroxidation in microsomes

    Energy Technology Data Exchange (ETDEWEB)

    Varshney, R.; Kale, R.K. (Jawaharlal Nehru Univ., New Delhi (India). School of Life Sciences)


    Rat liver microsomes were irradiated with {gamma}-rays at a dose of 1.31 Gy s{sup -1}. The extent of lipid peroxidation, measured in terms of malondialdehyde (MDA) formed, increased with radiation dose. The presence of calmodulin antagonists during irradiation decreased lipid peroxidation. The order of their protective efficiency was: chlorpromazine (CPZ)>promethazine (PMZ)>trimeprazine (TMZ). Their protective effect was diminished in the presence of ferrous (Fe{sup 2+}) ions and was restored on addition of EDTA. However, calmodulin antagonists considerably inhibited radiation-induced lipid peroxidation in the presence of ferric (Fe{sup 3+}) ions. Calmodulin antagonists also decreased the cytochrome P-450 content of microsomes. These results are discussed with respect to their applicability to radiotherapy. A possible mechanism for the inhibition of radiation-induced lipid peroxidation is suggested. (author).

  7. New antagonist agents of neuropeptide y receptors

    Directory of Open Access Journals (Sweden)

    Ignacio Aldana


    Full Text Available In the CNS, NPY has been implicated in obesity and feeding, endocrine function and metabolism. Potent and selective rNPY antagonists will be able to probe the merits of this approach for the treatment of obesity. We report the synthesis and preliminary evaluation of some hydrazide derivatives as antagonists of rNPY.

  8. Reciprocal inhibition in man. (United States)

    Crone, C


    Reciprocal inhibition is the automatic antagonist alpha motor neurone inhibition which is evoked by contraction of the agonist muscle. This so-called natural reciprocal inhibition is a ubiquitous and pronounced phenomenon in man and must be suspected of playing a major role in the control of voluntary movements. The spinal pathways underlying this inhibitory phenomenon were studied. The disynaptic reciprocal Ia inhibitory pathway between the tibial anterior muscle and the soleus alpha motor neurones was identified and described in man. It was shown that the inhibition can be evoked in most healthy subjects at rest, but the degree of inhibition varies considerably from one subject to another. It was concluded that it corresponds to the disynaptic reciprocal Ia inhibitory pathway which has been extensively described in animal experiments. The disynaptic reciprocal inhibition was shown to increase during the dynamic phase of a dorsiflexion movement of the foot, but not during the tonic phase. However, when the peripheral afferent feedback from the contracting muscle was blocked by ischaemia, an increase of the inhibition was revealed also during the tonic phase of the dorsiflexion. The concealment of this increase during unrestrained peripheral feedback from the muscle was thought to be due to the post-activation depression mechanism; a mechanism which was described further and which probably involves reduced transmitter release at Ia afferent terminals as a result of previous activation of these afferent fibers. Hence the hypothesis was supported that alpha motor neurones and the corresponding inhibitory interneurones, which project reciprocal inhibition to the antagonist motor neurones, are activated in parallel during voluntary contraction of agonist muscles. An additional reciprocal inhibitory mechanism, the long latency reciprocal inhibition, was described between the tibial anterior muscle and the soleus alpha motor neurones. It was shown to be evoked by group I

  9. Screening of Antagonistic Bacteria from Phyllosphere towards Tobacco Brown Spot Fungus Alternaria alternata

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chengsheng; KONG Fanyu; LI Duochuan; WANG Jing; WANG Fenglong


    The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties. They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A. alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate (filtrate to fungal spores inocula mixed in proportion 1: 50). These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.

  10. Antagonists of chemoattractants reveal separate receptors for cAMP, folic acid and pterin in Dictyostelium

    NARCIS (Netherlands)

    Haastert, Peter J.M. van; Wit, René J.W. de; Konijn, Theo M.


    Adenosine 3’,5’-monophosphate (cAMP), folic acid and pterin are chemoattractants in the cellular slime molds. The cAMP analog, 3’-amino-cAMP, inhibits a chemotactic reaction to cAMP at a concentration at which the analog is chemotactically inactive. The antagonistic effect of 3’-amino-cAMP on the ch

  11. Behavioural interactions between 5-hydroxytryptophan, neuroleptic agents and 5-HT receptor antagonists in modifying rodent responding to aversive situations.



    1. The ability of 5-hydroxytryptophan, 5-HT2 receptor antagonists and typical and atypical neuroleptic agents to modify behavioural responding to aversive situations was investigated in the mouse light/dark test and rat social interaction. 2. The administration of 5-hydroxytryptophan inhibited rat social interaction and the exploratory behaviour of mice in the light/dark test. 3. The 5-HT2 receptor antagonists, ketanserin, ritanserin, MDL11939, methysergide and RP62203, the neuroleptic agents...

  12. Implications of hedgehog signaling antagonists for cancer therapy

    Institute of Scientific and Technical Information of China (English)

    Jingwu Xie


    The hedgehog(Hh)pathway,initially discovered inDrosophila by two Nobel laureates,Dr.Eric Wieschaus and Dr.Christiane Nusslein-Volhard,is a major regulator for cell differentiation,tissue polarity and cell proliferation.Studies from many laboratories,including ours,reveal activation of this pathway in most basal cell carcinomas and in approximately 30% of extracutaneous human cancers,including medulloblastomas,gastrointestinal,lung,breast and prostate cancers.Thus,it is believed that targeted inhibition of Hh signaling may be effective in treating and preventing many types of human cancers.Even more exciting is the discovery and synthesis of specific signaling antagonists for the Hh pathway,which have significant clinical implications in novel cancer therapeutics.This review discusses the major advances in the current understanding of Hh signaling activation in different types of human cancers,the molecular basis of Hh signaling activation,the major antagonists for Hh signaling inhibition and their potential clinical application in human cancer therapy.

  13. Antagonists of the kappa opioid receptor. (United States)

    Urbano, Mariangela; Guerrero, Miguel; Rosen, Hugh; Roberts, Edward


    The research community has increasingly focused on the development of OPRK antagonists as pharmacotherapies for the treatment of depression, anxiety, addictive disorders and other psychiatric conditions produced or exacerbated by stress. Short-acting OPRK antagonists have been recently developed as a potential improvement over long-acting prototypic ligands including nor-BNI and JDTic. Remarkably the short-acting LY2456302 is undergoing phase II clinical trials for the augmentation of the antidepressant therapy in treatment-resistant depression. This Letter reviews relevant chemical and pharmacological advances in the identification and development of OPRK antagonists.

  14. Antagonistic formation motion of cooperative agents

    Institute of Scientific and Technical Information of China (English)

    卢婉婷; 代明香; 薛方正


    This paper investigates a new formation motion problem of a class of first-order multi-agent systems with antagonis-tic interactions. A distributed formation control algorithm is proposed for each agent to realize the antagonistic formation motion. A sufficient condition is derived to ensure that all agents make an antagonistic formation motion in a distributed manner. It is shown that all agents can be spontaneously divided into several groups, and agents in the same group collab-orate while agents in different groups compete. Finally, a numerical simulation is included to demonstrate our theoretical results.

  15. Histamine H3 receptor antagonist decreases cue-induced alcohol reinstatement in mice. (United States)

    Nuutinen, Saara; Mäki, Tiia; Rozov, Stanislav; Bäckström, Pia; Hyytiä, Petri; Piepponen, Petteri; Panula, Pertti


    We have earlier found that the histamine H3 receptor (H3R) antagonism diminishes motivational aspects of alcohol reinforcement in mice. Here we studied the role of H3Rs in cue-induced reinstatement of alcohol seeking in C57BL/6J mice using two different H3R antagonists. Systemic administration of H3R antagonists attenuated cue-induced alcohol seeking suggesting that H3R antagonists may reduce alcohol craving. To understand how alcohol affects dopamine and histamine release, a microdialysis study was performed on C57BL/6J mice and the levels of histamine, dopamine and dopamine metabolites were measured in the nucleus accumbens. Alcohol administration was combined with an H3R antagonist pretreatment to reveal whether modulation of H3R affects the effects of alcohol on neurotransmitter release. Alcohol significantly increased the release of dopamine in the nucleus accumbens but did not affect histamine release. Pretreatment with H3R antagonist ciproxifan did not modify the effect of alcohol on dopamine release. However, histamine release was markedly increased with ciproxifan. In conclusion, our findings demonstrate that H3R antagonism attenuates cue-induced reinstatement of alcohol seeking in mice. Alcohol alone does not affect histamine release in the nucleus accumbens but H3R antagonist instead increases histamine release significantly suggesting that the mechanism by which H3R antagonist inhibits alcohol seeking found in the present study and the decreased alcohol reinforcement, reward and consumption found earlier might include alterations in the histaminergic neurotransmission in the nucleus accumbens. These findings imply that selective antagonists of H3Rs could be a therapeutic strategy to prevent relapse and possibly diminish craving to alcohol use. This article is part of the Special Issue entitled 'Histamine Receptors'.

  16. Discovery of Isoquinolinoquinazolinones as a Novel Class of Potent PPARγ Antagonists with Anti-adipogenic Effects (United States)

    Jin, Yifeng; Han, Younho; Khadka, Daulat Bikram; Zhao, Chao; Lee, Kwang Youl; Cho, Won-Jea


    Conformational change in helix 12 can alter ligand-induced PPARγ activity; based on this reason, isoquinolinoquinazolinones, structural homologs of berberine, were designed and synthesized as PPARγ antagonists. Computational docking and mutational study indicated that isoquinolinoquinazolinones form hydrogen bonds with the Cys285 and Arg288 residues of PPARγ. Furthermore, SPR results demonstrated strong binding affinity of isoquinolinoquinazolinones towards PPARγ. Additionally, biological assays showed that this new series of PPARγ antagonists more strongly inhibit adipocyte differentiation and PPARγ2-induced transcriptional activity than GW9662. PMID:27695006

  17. Neurokinin-1 receptor antagonists as antitumor drugs in gastrointestinal cancer: A new approach

    Directory of Open Access Journals (Sweden)

    Miguel Muñoz


    Full Text Available Gastrointestinal (GI cancer is the term for a group of cancers affecting the digestive system. After binding to the neurokinin-1 (NK-1 receptor, the undecapeptide substance P (SP regulates GI cancer cell proliferation and migration for invasion and metastasis, and controls endothelial cell proliferation for angiogenesis. SP also exerts an antiapoptotic effect. Both SP and the NK-1 receptor are located in GI tumor cells, the NK-1 receptor being overexpressed. By contrast, after binding to the NK-1 receptor, NK-1 receptor antagonists elicit the inhibition (epidermal growth factor receptor inhibition of the proliferation of GI cancer cells in a concentration-dependent manner, induce the death of GI cancer cells by apoptosis, counteract the Warburg effect, inhibit cancer cell migration (counteracting invasion and metastasis, and inhibit angiogenesis (vascular endothelial growth factor inhibition. NK-1 receptor antagonists are safe and well tolerated. Thus, the NK-1 receptor could be considered as a new target in GI cancer and NK-1 receptor antagonists (eg, aprepitant could be a new promising approach for the treatment of GI cancer.

  18. Discovery and characterization of non-competitive antagonists of group I metabotropic glutamate receptors. (United States)

    Gasparini, F; Floersheim, P; Flor, P J; Heinrich, M; Inderbitzin, W; Ott, D; Pagano, A; Stierlin, C; Stoehr, N; Vranesic, I; Kuhn, R


    We have investigated the mechanism of inhibition of the new group I mGluR antagonists CPCCOEt and MPEP and determined that both compounds have a non-competitive mode of inhibition. Furthermore using chimeric/mutated receptors constructs we have found that these antagonists act at a novel pharmacological site located in the trans-membrane (TM). Specific non-conserved amino acid residues in the TM domain have been identified which are necessary for the inhibition by CPCCOEt and MPEP of the mGlul and mGlu5 receptors, respectively. Using molecular modeling a model of the TM domain was built for both mGlu1 and mGlu5 receptor subtypes. Docking of CPCCOEt and MPEP into their respective model allowed the modelisation of the novel binding site.

  19. Antagonistic action of pitrazepin on human and rat GABAA receptors (United States)

    Demuro, Angelo; Martinez-Torres, Ataulfo; Francesconi, Walter; Miledi, Ricardo


    Pitrazepin, 3-(piperazinyl-1)-9H-dibenz(c,f) triazolo(4,5-a)azepin is a piperazine antagonist of GABA in a variety of electrophysiological and in vitro binding studies involving GABA and glycine receptors. In the present study we have investigated the effects of pitrazepin, and the GABAA antagonist bicuculline, on membrane currents elicited by GABA in Xenopus oocytes injected with rat cerebral cortex mRNA or cDNAs encoding α1β2 or α1β2γ2S human GABAA receptor subunits.The three types of GABAA receptors expressed were reversibly antagonized by bicuculline and pitrazepin in a concentration-dependent manner. GABA dose-current response curves for the three types of receptors were shifted to the right, in a parallel manner, by increasing concentrations of pitrazepin.Schild analyses gave pA2 values of 6.42±0.62, n=4, 6.41±1.2, n=5 and 6.21±1.24, n=6, in oocytes expressing rat cerebral cortex, α1β2 or α1β2γ2S human GABAA receptors respectively (values are given as means±s.e.mean), and the Hill coefficients were all close to unity. All this is consistent with the notion that pitrazepin acts as a competitive antagonist of these GABAA receptors; and that their antagonism by pitrazepin is not strongly dependent on the subunit composition of the receptors here studied.Since pitrazepin has been reported to act also at the benzodiazepine binding site, we studied the effect of the benzodiazepine antagonist Ro 15-1788 (flumazenil) on the inhibition of α1β2γ2S receptors by pitrazepin. Co-application of Ro 15-1788 did not alter the inhibiting effect of pitrazepin. Moreover, pitrazepin did not antagonize the potentiation of GABA-currents by flunitrazepam. All this suggests that pitrazepin does not affect the GABA receptor-chloride channel by interacting with the benzodiazepine receptor site. PMID:10369456

  20. Phenylthiophenecarboxamide antagonists of the olfactory receptor co-receptor subunit from a mosquito.

    Directory of Open Access Journals (Sweden)

    Sisi Chen

    Full Text Available Insects detect environmental chemicals using chemosensory receptors, such as the ORs, a family of odorant-gated ion channels. Insect ORs are multimeric complexes of unknown stoichiometry, formed by a common subunit (the odorant receptor co-receptor subunit, Orco and one of many variable subunits that confer odorant specificity. The recent discovery of Orco directed ligands, including both agonists and antagonists, suggests Orco as a promising target for chemical control of insects. In addition to competitively inhibiting OR activation by Orco agonists, several Orco antagonists have been shown to act through a non-competitive mechanism to inhibit OR activation by odorants. We previously identified a series of Orco antagonists, including N-(4-ethylphenyl-2-thiophenecarboxamide (OX1a, previously referred to as OLC20. Here, we explore the chemical space around the OX1a structure to identify more potent Orco antagonists. Cqui\\Orco+Cqui\\Or21, an OR from Culex quinquefasciatus (the Southern House Mosquito that responds to 3-methylindole (skatole and is thought to mediate oviposition behavior, was expressed in Xenopus oocytes and receptor function assayed by two-electrode voltage clamp electrophysiology. 22 structural analogs of OX1a were screened for antagonism of OR activation by an Orco agonist. By varying the moieties decorating the phenyl and thiophene rings, and altering the distance between the rings, we were able to identify antagonists with improved potency. Detailed examination of three of these compounds (N-mesityl-2-thiophenecarboxamide, N-(4-methylbenzyl-2-thiophenecarboxamide and N-(2-ethylphenyl-3-(2-thienyl-2-propenamide demonstrated competitive inhibition of receptor activation by an Orco agonist and non-competitive inhibition of receptor activation by an odorant. The ability to inhibit OR activation by odorants may be a general property of this class of Orco antagonist, suggesting that odorant mediated behaviors can be manipulated


    Directory of Open Access Journals (Sweden)



    Full Text Available Four fungal isolates from soils obtained from three sites of the oil palm plantations in North Sumatra were found antagonistic to Ganoderma boninense, the causal agent of basal stem rot of oil palm. Penicillium citrinum inhibited the growth of the pathogen and formed a zone of inhibition on the agar media. Trichoderma harzianum BIO - 1 as well as BIO - 2 and T. viride not only repressed the growth of the pathogen but also caused lysis of the hyphae, and the colony was totally overgrown by the antagonists.

  2. Structure-Based Design of a Periplasmic Binding Protein Antagonist that Prevents Domain Closure

    Energy Technology Data Exchange (ETDEWEB)

    Borrok, M. Jack; Zhu, Yimin; Forest, Katrina T.; Kiessling, Laura L.; (UW)


    Many receptors undergo ligand-induced conformational changes to initiate signal transduction. Periplasmic binding proteins (PBPs) are bacterial receptors that exhibit dramatic conformational changes upon ligand binding. These proteins mediate a wide variety of fundamental processes including transport, chemotaxis, and quorum sensing. Despite the importance of these receptors, no PBP antagonists have been identified and characterized. In this study, we identify 3-O-methyl-D-glucose as an antagonist of glucose/galactose-binding protein and demonstrate that it inhibits glucose chemotaxis in E. coli. Using small-angle X-ray scattering and X-ray crystallography, we show that this antagonist acts as a wedge. It prevents the large-scale domain closure that gives rise to the active signaling state. Guided by these results and the structures of open and closed glucose/galactose-binding protein, we designed and synthesized an antagonist composed of two linked glucose residues. These findings provide a blueprint for the design of new bacterial PBP inhibitors. Given the key role of PBPs in microbial physiology, we anticipate that PBP antagonists will have widespread uses as probes and antimicrobial agents.

  3. Dual action of neurokinin-1 antagonists on Mas-related GPCRs (United States)

    Azimi, Ehsan; Reddy, Vemuri B.; Shade, Kai-Ting C.; Anthony, Robert M.; Pereira, Paula Juliana Seadi; Lerner, Ethan A.


    The challenge of translating findings from animal models to the clinic is well known. An example of this challenge is the striking effectiveness of neurokinin-1 receptor (NK-1R) antagonists in mouse models of inflammation coupled with their equally striking failure in clinical investigations in humans. Here, we provide an explanation for this dichotomy: Mas-related GPCRs (Mrgprs) mediate some aspects of inflammation that had been considered mediated by NK-1R. In support of this explanation, we show that conventional NK-1R antagonists have off-target activity on the mouse receptor MrgprB2 but not on the homologous human receptor MRGPRX2. An unrelated tripeptide NK-1R antagonist has dual activity on MRGPRX2. This tripeptide both suppresses itch in mice and inhibits degranulation from the LAD-2 human mast cell line elicited by basic secretagogue activation of MRGPRX2. Antagonists of Mrgprs may fill the void left by the failure of NK-1R antagonists. PMID:27734033

  4. Evodiamine as a novel antagonist of aryl hydrocarbon receptor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hui [State Key Laboratory of Trauma, Burns, and Combined Injury, Department 1, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China); Department of Laboratory Medicine, The Affiliated Tenth People' s Hospital, Tongji University, Shanghai 200072 (China); Tu, Yongjiu; Zhang, Chun; Fan, Xia; Wang, Xi [State Key Laboratory of Trauma, Burns, and Combined Injury, Department 1, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China); Wang, Zhanli [College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014 (China); Liang, Huaping, E-mail: [State Key Laboratory of Trauma, Burns, and Combined Injury, Department 1, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China)


    Research highlights: {yields} Evodiamine interacted with the AhR. {yields} Evodiamine inhibited the specific binding of [{sup 3}H]-TCDD to the AhR. {yields} Evodiamine acts as an antagonist of the AhR. -- Abstract: Evodiamine, the major bioactive alkaloid isolated from Wu-Chu-Yu, has been shown to interact with a wide variety of proteins and modify their expression and activities. In this study, we investigated the interaction between evodiamine and the aryl hydrocarbon receptor (AhR). Molecular modeling results revealed that evodiamine directly interacted with the AhR. Cytosolic receptor binding assay also provided the evidence that evodiamine could interact with the AhR with the K{sub i} value of 28.4 {+-} 4.9 nM. In addition, we observed that evodiamine suppressed the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced nuclear translocation of the AhR and the expression of CYP1A1 dose-dependently. These results suggested that evodiamine was able to bind to the AhR as ligand and exhibit antagonistic effects.

  5. CCR9 Antagonists in the Treatment of Ulcerative Colitis

    Directory of Open Access Journals (Sweden)

    Pirow Bekker


    Full Text Available While it has long been established that the chemokine receptor CCR9 and its ligand CCL25 are essential for the movement of leukocytes into the small intestine and the development of small-intestinal inflammation, the role of this chemokine-receptor pair in colonic inflammation is not clear. Toward this end, we compared colonic CCL25 protein levels in healthy individuals to those in patients with ulcerative colitis. In addition, we determined the effect of CCR9 pharmacological inhibition in the mdr1a−/− mouse model of ulcerative colitis. Colon samples from patients with ulcerative colitis had significantly higher levels of CCL25 protein compared to healthy controls, a finding mirrored in the mdr1a−/− mice. In the mdr1a−/− mice, CCR9 antagonists significantly decreased the extent of wasting and colonic remodeling and reduced the levels of inflammatory cytokines in the colon. These findings indicate that the CCR9:CCL25 pair plays a causative role in ulcerative colitis and suggest that CCR9 antagonists will provide a therapeutic benefit in patients with colonic inflammation.

  6. Suppression of Aldosterone Synthesis and Secretion by Channel Antagonists

    Directory of Open Access Journals (Sweden)

    Keiichi Ikeda


    Full Text Available Aldosterone, a specific mineralocorticoid receptor (MR agonist and a key player in the development of hypertension, is synthesized as a final product of renin-angiotensin-aldosterone system. Hypertension can be generally treated by negating the effects of angiotensin II through the use of angiotensin-converting enzyme inhibitors (ACE-Is or angiotensin II type 1 receptor antagonists (ARBs. However, the efficacy of angiotensin II blockade by such drugs is sometimes diminished by the so-called “aldosterone breakthrough” effect, by which ACE-Is or ARBs (renin-angiotensin system (RAS inhibitors gradually lose their effectiveness against hypertension due to the overproduction of aldosterone, known as primary aldosteronism. Although MR antagonists are used to antagonize the effects of aldosterone, these drugs may, however, give rise to life-threatening adverse actions, such as hyperkalemia, particularly when used in conjunction with RAS inhibitors. Recently, several groups have reported that some dihydropyridine Ca2+ channel blockers (CCBs have inhibitory actions on aldosterone production in in vitro and in the clinical setting. Therefore, the use of such dihydropyridine CCBs to treat aldosterone-related hypertension may prove beneficial to circumvent such therapeutic problems. In this paper, we discuss the mechanism of action of CCBs on aldosterone production and clinical perspectives for CCB use to inhibit MR activity in hypertensive patients.

  7. Intracerebroventricular administration of histamine H3 receptor antagonists decreases seizures in rat models of epilepsia. (United States)

    Harada, C; Hirai, T; Fujii, Y; Harusawa, S; Kurihara, T; Kamei, C


    The effects of histamine H3 antagonists on amygdaloid kindled and maximal electroshock seizures in rats were studied to determine their potential as new antiepileptic drugs. Under pentobarbital anesthesia, rats were fixed to a stereotaxic apparatus and a stainless steel guide cannula for drug administration was implanted into the lateral ventricle. In amygdaloid kindled seizures, electrodes were implanted into the right amygdala and electroencephalogram was recorded bipolarly; stimulation was applied bipolarly every day by a constant current stimulator and continued until a generalized convulsion was obtained. In the maximal electroshock (MES) seizure test, electroconvulsion was induced by stimulating animals through ear-clip electrodes, and the durations of tonic and clonic seizures were measured. Thioperamide, clobenpropit, iodophenpropit, VUF5514, VUF5515 and VUF4929 caused a dose-dependent inhibition of both seizure stage and afterdischarge (AD) duration of amygdaloid kindled seizures. The duration of tonic seizure induced by MES was also inhibited by H3 antagonists, but the duration of clonic seizures were unchanged. Among the H3 antagonists tested, clobenpropit and iodophenpropit were somewhat more potent than the other drugs on amygdaloid kindled seizures and MES seizures, respectively. These results indicate that some H3 antagonists may be useful as antiepileptic drugs, especially for secondary generalized seizures and/or tonic-clonic seizures in humans.

  8. Auxin-Oxylipin Crosstalk: Relationship of Antagonists

    Institute of Scientific and Technical Information of China (English)

    Maik Hoffmann; Mathias Hentrich; Stephan Pollmann


    Phytohormones regulate a wide array of developmental processes throughout the life cycle of plants. Herein, the various plant hormones may interact additively, synergistically, or antagonistically. By their cooperation they create a delicate regulatory network whose net output largely depends on the action of specific phytohormone combinations rather than on the independent activities of separate hormones. While most classical studies of plant hormonal control have focused mainly on the action of single hormones or on the synergistic interaction of hormones in regulating various developmental processes, recent work is beginning to shed light on the crosstalk of nominally antagonistic plant hormones, such as gibberellins and auxins with oxylipins or abscisic acid. In this review, we summarize our current understanding of how two of the first sight antagonistic plant hormones, i.e. auxins and oxylipins,interact in controlling plant responses and development.

  9. Effects of a gonadotropin-releasing hormone antagonist on gonadotropin levels in Masu salmon and Sockeye salmon. (United States)

    Amano, Masafumi; Ikuta, Kazumasa; Kitamura, Shoji


    The salmon gonadotropin-releasing hormone (sGnRH) is considered to be involved in gonadal maturation via gonadotropin (GTH) secretion in salmonid fishes. However, there is no direct evidence for endogenous sGnRH-stimulated GTH secretion in salmonids. In this study, to clarify whether endogenous sGnRH stimulates GTH secretion, we examined the effects of the mammalian GnRH (mGnRH) antagonist [Ac-Delta(3)-Pro(1), 4FD-Phe(2), D-Trp(3,6)]-mGnRH on luteinizing hormone (LH) levels in 0-year-old masu salmon Oncorhynchus masou and sockeye salmon Oncorhynchus nerka. First, the effects of the GnRH antagonist on LH release were examined in 0-year-old precocious male masu salmon. GnRH antagonist treatment for 3 hr significantly inhibited an increase in plasma LH levels that was artificially induced by exogenous sGnRH administration, indicating that the GnRH antagonist is effective in inhibiting LH release from the pituitary. Subsequently, we examined the effect of the GnRH antagonist on LH synthesis in 0-year-old immature sockeye salmon that were pretreated with exogenous testosterone for 42 days to increase the pituitary LH contents; the testosterone treatment did not affect the plasma LH levels. GnRH antagonist treatment slightly but significantly inhibited an increase in the testosterone-stimulated pituitary LH content levels. However, no significant differences in the plasma LH levels were observed between the GnRH antagonist-treated and control groups. These results suggest that endogenous sGnRH is involved in LH secretion in salmonid fishes.

  10. Genetic factors influencing pyrimidine-antagonist chemotherapy

    NARCIS (Netherlands)

    Maring, JG; Groen, HJM; Wachters, FM; Uges, DRA; de Vries, EGE


    Pyrimidine antagonists, for example, 5-fluorouracil (5-FU), cytarabine (ara-C) and gemcitabine (dFdC), are widely used in chemotherapy regimes for colorectal, breast, head and neck, non-small-cell lung cancer, pancreatic cancer and leukaemias. Extensive metabolism is a prerequisite for conversion of

  11. Pharmacology of JB-9315, a new selective histamine H2-receptor antagonist. (United States)

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


    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.

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

    Hansen, Kasper B; Mullasseril, Praseeda; Dawit, Sara; Kurtkaya, Natalie L; Yuan, Hongjie; Vance, Katie M; Orr, Anna G; Kvist, Trine; Ogden, Kevin K; Le, Phuong; Vellano, Kimberly M; Lewis, Iestyn; Kurtkaya, Serdar; Du, Yuhong; Qui, Min; Murphy, T J; Snyder, James P; Bräuner-Osborne, Hans; Traynelis, Stephen F


    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 concentrations of glutamate and glycine to minimize detection of competitive antagonists. The assay is validated by successfully identifying known noncompetitive, but not competitive NMDA receptor antagonists among 1800 screened compounds from two small focused libraries, including the commercially available library of pharmacologically active compounds. Hits from the primary screen are validated through a secondary screen that used two-electrode voltage-clamp recordings on recombinant NMDA receptors expressed in Xenopus laevis oocytes. This strategy identified several novel modulators of NMDA receptor function, including the histamine H3 receptor antagonists clobenpropit and iodophenpropit, as well as the vanilloid receptor transient receptor potential cation channel, subfamily V, member 1 (TRPV1) antagonist capsazepine. These compounds are noncompetitive antagonists and the histamine H3 receptor ligand showed submicromolar potency at NR1/NR2B NMDA receptors, which raises the possibility that compounds can be developed that act with high potency on both glutamate and histamine receptor systems simultaneously. Furthermore, it is possible that some actions attributed to histamine H3 receptor inhibition in vivo may also involve NMDA receptor antagonism.

  13. Characterization of PCS1055, a novel muscarinic M4 receptor antagonist. (United States)

    Croy, Carrie H; Chan, Wai Y; Castetter, Andrea M; Watt, Marla L; Quets, Anne T; Felder, Christian C


    Identification of synthetic ligands selective for muscarinic receptor subtypes has been challenging due to the high sequence identity and structural homology among the five muscarinic acetylcholine receptors. Here, we report the pharmacological characterization of PCS1055, a novel muscarinic M4 receptor antagonist. PCS1055 inhibited radioligand [(3)H]-NMS binding to the M4 receptor with a Ki=6.5nM. Though the potency of PCS1055 is lower than that of pan-muscarinic antagonist atropine, it has better subtype selectivity over previously reported M4-selective reagents such as the muscarinic-peptide toxins (Karlsson et al., 1994; Santiago and Potter, 2001a) at the M1 subtype, and benzoxazine ligand PD102807 at the M3-subtype (Bohme et al., 2002). A detailed head-to-head comparison study using [(3)H]-NMS competitive binding assays characterizes the selectivity profiles of PCS1055 to that of other potent muscarinic-antagonist compounds PD102807, tropicamide, AF-DX-384, pirenzapine, and atropine. In addition to binding studies, the subtype specificity of PCS1055 is also demonstrated by functional receptor activation as readout by GTP-γ-[(35)S] binding. These GTP-γ-[(35)S] binding studies showed that PCS1055 exhibited 255-, 69.1-, 342- and >1000-fold greater inhibition of Oxo-M activity at the M4 versus the M1-, M2(-), M3-or M5 receptor subtypes, respectively. Schild analyses indicates that PCS1055 acts as a competitive antagonist to muscarinic M4 receptor, and confirms the affinity of the ligand to be low nanomolar, Kb=5.72nM. Therefore, PCS1055 represents a new M4-preferring antagonist that may be useful in elucidating the roles of M4 receptor signaling.

  14. Internalization of the chemokine receptor CCR4 can be evoked by orthosteric and allosteric receptor antagonists. (United States)

    Ajram, Laura; Begg, Malcolm; Slack, Robert; Cryan, Jenni; Hall, David; Hodgson, Simon; Ford, Alison; Barnes, Ashley; Swieboda, Dawid; Mousnier, Aurelie; Solari, Roberto


    The chemokine receptor CCR4 has at least two natural agonist ligands, MDC (CCL22) and TARC (CCL17) which bind to the same orthosteric site with a similar affinity. Both ligands are known to evoke chemotaxis of CCR4-bearing T cells and also elicit CCR4 receptor internalization. A series of small molecule allosteric antagonists have been described which displace the agonist ligand, and inhibit chemotaxis. The aim of this study was to determine which cellular coupling pathways are involved in internalization, and if antagonists binding to the CCR4 receptor could themselves evoke receptor internalization. CCL22 binding coupled CCR4 efficiently to β-arrestin and stimulated GTPγS binding however CCL17 did not couple to β-arrestin and only partially stimulated GTPγS binding. CCL22 potently induced internalization of almost all cell surface CCR4, while CCL17 showed only weak effects. We describe four small molecule antagonists that were demonstrated to bind to two distinct allosteric sites on the CCR4 receptor, and while both classes inhibited agonist ligand binding and chemotaxis, one of the allosteric sites also evoked receptor internalization. Furthermore, we also characterize an N-terminally truncated version of CCL22 which acts as a competitive antagonist at the orthosteric site, and surprisingly also evokes receptor internalization without demonstrating any agonist activity. Collectively this study demonstrates that orthosteric and allosteric antagonists of the CCR4 receptor are capable of evoking receptor internalization, providing a novel strategy for drug discovery against this class of target.

  15. 7-Chloroarctinone-b as a new selective PPARγ antagonist potently blocks adipocyte differentiation

    Institute of Scientific and Technical Information of China (English)

    Yong-tao LI; Li LI; Jing CHEN; Tian-cen HU; Jin HUANG; Yue-wei GUO; Hua-liang JIANG; Xu SHEN


    Aim: Peroxisome proliferator-activated receptor gamma (PPARy) is a therapeutic target for obesity, cancer and diabetes mellitus. In order to develop potent lead compounds for obesity treatment, we screened a natural product library for novel PPARy antagonists with inhibitory effects on adipocyte differentiation. Methods: Surface plasmon resonance (SPR) technology and cell-based transactivation assay were used to screen for PPARy antago-nists. To investigate the antagonistic mechanism of the active compound, we measured its effect on PPARy/RXRα heterodimerization and PPARy co-activator recruitment using yeast two-hybrid assay, Gal4/UAS cell-based assay and SPR based assay. The 3T3-L1 cell differentiation assay was used to evaluate the effect of the active compound on adipocyte differentiation. Results: A new thiophene-acetylene type of natural product, 7-chloroarctinone-b (CAB), isolated from the roots of Rhaponticum uniflo-rum, was discovered as a novel PPARγ antagonist capable of inhibiting rosiglitazone-induced PPARγ transcriptional activity. SPR analy-sis suggested that CAB bound tightly to PPARγ and considerably antagonized the potent PPARy agonist rosigtitazone-stimulated PPARγ-LBD/RXRα-LBD binding. Gal4/UAS and yeast two-hybrid assays were used to evaluate the antagonistic activity of CAB on rosiglitazone-induced recruitment of the coactivator for PPARy. CAB could efficiently antagonize both hormone and rosiglitazone-induced adipocyte differentiation in cell culture. Conclusion: CAB shows antagonistic activity to PPARγ and can block the adipocyte differentiation, indicating it may be of potential use as a lead therapeutic compound for obesity.


    Institute of Scientific and Technical Information of China (English)


    Objective. To investigate whether angiotensin II receptor antagonist and endothelin receptor antagonist can improve the nitroglycerin (Nit) tolerance in vivo. Methods. Twenty-four rats were divided into 4 groups (n=6,each): Control group, Nitroglycerin (Nit) group, Nit+ bosentan group and Nit+ losartan group. Nitroglycerin tolerance was induced by 2-day treatment of nitroglycerin patch (0.05 mg/h). AngiotensinⅡ receptor antagonist losartan ( 10 mg· kg- 1· d- 1 ) and endothelin receptor antagonist bosentan ( 100 mg· kg- 1· d- 1 ) were given by gavage for 2 days respectively. Results. The least hypotensive response to sodium nitroprusside (SNP) was observed in Nit group . The effective percentages of hypotensive response to SNP were increased in both Nit+ losartan group and Nit+ bosentan group compared with Nit group [(31.95± 4.45 ) % vs (21.00± 3.69 ) % , P Conclusion. Endothelin receptor antagonist and angiotensin Ⅱ receptor antagonist could prevent against the Nit tolerance .

  17. The substance P/NK-1 receptor system: NK-1 receptor antagonists as anti-cancer drugs

    Indian Academy of Sciences (India)

    Miguel Muñoz; Rafael Coveñas; Francisco Esteban; Maximino Redondo


    The substance P (SP)/neurokinin (NK)-1 receptor system plays an important role in cancer. SP promotes the proliferation of tumour cells, angiogenesis and the migration of tumour cells. We review the involvement of SP, the NK-1 receptor and NK-1 receptor antagonists in cancer. Tumour cells overexpress NK-1 receptors, which are involved in their viability. This overexpression suggests the possibility of specific treatment against tumour cells using NK-1 receptor antagonists, thus promoting a considerable decrease in the side effects of the treatment. This strategy opens up new approaches for cancer treatment, since these antagonists, after binding to their molecular target, induce the death of tumour cells by apoptosis, exert an antiangiogenic action and inhibit the migration of tumour cells. The use of NK-1 receptor antagonists such as aprepitant (used in clinical practice) as antitumour agents could be a promising innovation. The value of aprepitant as an antitumour agent could be determined faster than for less well-known compounds because many studies addressing its safety and characterization have already been completed. The NK-1 receptor may be a promising target in the treatment of cancer; NK-1 receptor antagonists could act as specific drugs against tumour cells; and these antagonists could be new candidate anti-cancer drugs.

  18. Optimization of piperidin-4-yl-urea-containing melanin-concentrating hormone receptor 1 (MCH-R1) antagonists: Reducing hERG-associated liabilities. (United States)

    Berglund, Susanne; Egner, Bryan J; Gradén, Henrik; Gradén, Joakim; Morgan, David G A; Inghardt, Tord; Giordanetto, Fabrizio


    The discovery and optimization of piperidin-4-yl-urea derivatives as MCH-R1 antagonists is herein described. Previous work around the piperidin-4-yl-amides led to the discovery of potent MCH-R1 antagonists. However, high affinity towards the hERG potassium channel proved to be an issue. Different strategies to increase hERG selectivity were implemented and resulted in the identification of piperidin-4-yl-urea compounds as potent MCH-R1 antagonists with minimized hERG inhibition.

  19. The alpha7 nicotinic acetylcholine receptor-selective antagonist, methyllycaconitine, partially protects against beta-amyloid1-42 toxicity in primary neuron-enriched cultures. (United States)

    Martin, Shelley E; de Fiebre, Nancy Ellen C; de Fiebre, Christopher M


    Studies have suggested that the neuroprotective actions of alpha7 nicotinic agonists arise from activation of receptors and not from the extensive desensitization which rapidly follows activation. Here, we report that the alpha7-selective nicotinic antagonist, methyllycaconitine (MLA), protects against beta-amyloid-induced neurotoxicity; whereas the alpha4beta2-selective antagonist, dihydro-beta-erythroidine, does not. These findings suggest that neuroprotective actions of alpha7-acting agents arise from receptor inhibition/desensitization and that alpha7 antagonists may be useful neuroprotective agents.

  20. Mineralocorticoid and glucocorticoid receptor antagonists in animal models of anxiety

    NARCIS (Netherlands)

    Korte, SM; KorteBouws, GAH; Koob, GF; DeKloet, ER; Bohus, B


    The behavioral effects of intracerebroventricular (ICV) administration of a specific mineralocorticoid receptor (MR) antagonist [RU28318 (10-50 ng/2 mu l)], a glucocorticoid receptor (GR) antagonist [RU38486 (1-50 ng/2 mu l)], or both antagonists (50 ng/2 mu l), were studied in two different animal

  1. High affinity retinoic acid receptor antagonists: analogs of AGN 193109. (United States)

    Johnson, A T; Wang, L; Gillett, S J; Chandraratna, R A


    A series of high affinity retinoic acid receptor (RAR) antagonists were prepared based upon the known antagonist AGN 193109 (2). Introduction of various phenyl groups revealed a preference for substitution at the para-position relative to the meta-site. Antagonists with the highest affinities for the RARs possessed hydrophobic groups, however, the presence of polar functionality was also well tolerated.

  2. Novel benzimidazole-based MCH R1 antagonists. (United States)

    Carpenter, Andrew J; Al-Barazanji, Kamal A; Barvian, Kevin K; Bishop, Michael J; Britt, Christy S; Cooper, Joel P; Goetz, Aaron S; Grizzle, Mary K; Hertzog, Donald L; Ignar, Diane M; Morgan, Ronda O; Peckham, Gregory E; Speake, Jason D; Swain, Will R


    The identification of an MCH R1 antagonist screening hit led to the optimization of a class of benzimidazole-based MCH R1 antagonists. Structure-activity relationships and efforts to optimize pharmacokinetic properties are detailed along with the demonstration of the effectiveness of an MCH R1 antagonist in an animal model of obesity.

  3. Molecular characterizations of microbial antagonists and development of bioformulations for management of bacterial wilt of Naga Chilli (Capsicum chinens Jacq. in Assam

    Directory of Open Access Journals (Sweden)

    Lohit Kataki, Kuldeep Talukdar


    Full Text Available Aggressive strains of five different saprophytic antagonists Trichoderma parareesei TPJ-S-1, Trichoderma viride TVJ-S-1, Paecilomyces variotii Isolate-1, Bacillus thuringiensis BTJ-S-1 and Citrobacter farmeri CTJ-S-1 and their consortial formulations were evaluated during 2012-14, for their effectiveness in management of bacterial wilt disease (c. o. Ralstonia solanacearum of Naga chilli (Capsicum chinens Jacq.. The molecular characterization of selected antagonists was undertaken to determine their distinctiveness from their close relatives through sequencing of the 18S & 28S region of ribosomal DNA in case of fungal antagonists and 16S region in case of bacterial antagonists along with its phylogenetic analysis. The antagonistic potential of the five microbes were tested in vitro singly and in consortia against R. solanacearum adopting dual culture method. Altogether 31 treatment combinations were compared; the inhibition zones (mm and percent inhibitions were recorded and analyzed. The highest inhibition (91.47% against R. solanacearum was recorded in consortia of T. parareesei, T. viride and B. thuringiensis followed by the consortia of T. parareesei, T. viride, P. variotii, B. thuringiensis and C. farmeri (82.22%. Quantitative aspect of population dynamics of selected antagonists in three different substrate carrier viz. vermicompost, talcum powder (TP and mustard oil cake (MOC were compared to evaluate their shelf – life at different days of storage

  4. Cetirizine inhibits skin reactions but not mediator release in immediate and developing late-phase allergic cutaneous reactions. A double-blind, placebo-controlled study

    DEFF Research Database (Denmark)

    Nielsen, P N; Skov, P S; Poulsen, Lars K.


    Recent reports have indicated cetirizine, a potent H(1)-receptor antagonist, to possess a number of anti-inflammatory effects, e.g. inhibition of mast cell degranulation and inhibition of leucocyte migration and activation....

  5. [Cutaneous adverse effects of TNFalpha antagonists]. (United States)

    Failla, V; Sabatiello, M; Lebas, E; de Schaetzen, V; Dezfoulian, B; Nikkels, A F


    The TNFalpha antagonists, including adalimumab, etanercept and infliximab, represent a class of anti-inflammatory and immunosuppressive drugs. Although cutaneous adverse effects are uncommon, they are varied. There is no particular risk profile to develop cutaneous adverse effects. The principal acute side effects are injection site reactions and pruritus. The major long term cutaneous side effects are infectious and inflammatory conditions. Neoplastic skin diseases are exceptional. The association with other immunosuppressive agents can increase the risk of developing cutaneous adverse effects. Some adverse effects, such as lupus erythematosus, require immediate withdrawal of the biological treatment, while in other cases temporary withdrawal is sufficient. The majority of the other cutaneous adverse effects can be dealt without interrupting biologic treatment. Preclinical and clinical investigations revealed that the new biologics, aiming IL12/23, IL23 and IL17, present a similar profile of cutaneous adverse effects, although inflammatory skin reactions may be less often encountered compared to TNFalpha antagonists.

  6. Evidence for homogeneity of thromboxane A2 receptor using structurally different antagonists. (United States)

    Swayne, G T; Maguire, J; Dolan, J; Raval, P; Dane, G; Greener, M; Owen, D A


    Nine structurally dissimilar thromboxane antagonists (SQ 29548, ICI 185282, AH 23848, BM 13505 (Daltroban), BM 13177 (Sulotroban), SK&F 88046, L-636499, L-640035 and a Bayer compound SK&F 47821) were studied for activity as thromboxane A2 receptor antagonists. The assays used were inhibition of responses induced by the thromboxane mimetic, U46619, on human washed platelet aggregation, rabbit platelet aggregation, rabbit aortic strip contraction, anaesthetised guinea-pig bronchoconstriction, and a radio-labelled ligand (125I-PTA-OH) binding assay as a measure of affinity for the human platelet receptor. The results of the present study, with activities spanning at least four orders of magnitude along with statistically significant correlations (at least P less than 0.01), strongly suggests that between assays, antagonists and species a homogenous population of thromboxane A2 receptors exists. This finding is in contrast to those of a close series of 13-azapinane antagonists studied by other workers which have suggested receptor heterogeneity.

  7. Therapeutic efficacy and immunological response of CCL5 antagonists in models of contact skin reaction.

    Directory of Open Access Journals (Sweden)

    Miriam Canavese

    Full Text Available Skin-infiltrating T-cells play a predominant role in allergic and inflammatory skin diseases such as atopic dermatitis, psoriasis and allergic contact dermatitis. These T-cells are attracted by several chemotactic factors including the chemokine CCL5/RANTES, a CC chemokine inducing both the migration and activation of specific leukocyte subsets. CCL5 has been found to be associated with various cell-mediated hypersensitive disorders such as psoriasis, atopic dermatitis and irritant contact dermatitis. We have used two antagonists, the first, Met-CCL5, a dual CCR1/CCR5 antagonist and the second, a variant in which GAG binding is abrogated, (44AANA(47-CCL5, which acts as a dominant negative inhibitor of CCL5. The antagonists were tested in two models of contact skin reaction. The first, irritant contact dermatitis (ICD is a pathological non-specific inflammatory skin condition arising from the release of pro-inflammatory cytokines by keratinocytes in response to haptens, usually chemicals. The second, contact hypersensitivity (CHS is a T-cell dependent model, mimicking in part the T-cell-mediated skin diseases such as psoriasis. In both models, the CCL5 antagonists showed therapeutic efficacy by reducing swelling by 50% as well as the reduction of soluble mediators in homogenates derived from challenged ears. These results demonstrate that blocking the receptor or the ligand are both effective strategies to inhibit skin inflammation.

  8. Structure of a stapled peptide antagonist bound to nutlin-resistant Mdm2.

    Directory of Open Access Journals (Sweden)

    Sharon Min Qi Chee

    Full Text Available As key negative regulator of the p53 tumour suppressor, Mdm2 is an attractive therapeutic target. Small molecules such as Nutlin have been developed to antagonise Mdm2, resulting in p53-dependent death of tumour cells. We have recently described a mutation in Mdm2 (M62A, which precludes binding of Nutlin, but not p53. This Nutlin-resistant variant is not, however, refractory to binding and inhibition by stapled peptide antagonists targeting the same region of Mdm2. A detailed understanding of how stapled peptides are recalcitrant to Mdm2 mutations conferring Nutlin-resistance will aid in the further development of potent Mdm2 antagonists. Here, we report the 2.00 Å crystal structure of a stapled peptide antagonist bound to Nutlin resistant Mdm2. The stapled peptide relies on an extended network of interactions along the hydrophobic binding cleft of Mdm2 for high affinity binding. Additionally, as seen in other stapled peptide structures, the hydrocarbon staple itself contributes to binding through favourable interactions with Mdm2. The structure highlights the intrinsic plasticity present in both Mdm2 and the hydrocarbon staple moiety, and can be used to guide future iterations of both small molecules and stapled peptides for improved antagonists of Mdm2.

  9. Dynamics of Antagonistic Potency of Rhodobacter capsulatus PG Lipopolysaccharide against Endotoxin-Induced Effects. (United States)

    Kabanov, D S; Serov, D A; Zubova, S V; Grachev, S V; Prokhorenko, I R


    The dynamics of antagonistic potency of lipopolysaccharide (LPS) isolated from Rhodobacter capsulatus PG on the synthesis of proinflammatory (TNF-α, IL-1β, IL-8, IL-6, IFN-γ) and antiinflammatory (IL-10, IL-1Ra) cytokines induced by highly stimulatory endotoxins from Escherichia coli or Salmonella enterica have been studied. Using human whole blood, we have shown that R. capsulatus PG LPS inhibited most pronouncedly the endotoxin-induced synthesis of TNF-α, IL-1β, IL-8, and IL-6 during the first 6 h after endotoxin challenge. Similarly, the endotoxin-induced release of IFN-γ was abolished by R. capsulatus PG LPS as well (24 h). In contrast to the above-mentioned cytokines, the relatively weak antagonistic activity of R. capsulatus PG LPS against endotoxin-triggered production of IL-6 and IL-8 was revealed. Since R. capsulatus PG LPS displays more potent antagonistic activity against deleterious effects of S. enterica LPS than those of E. coli LPS in the cases of such cytokines as IL-1β (6 and 24 h), IL-6 and IL-8 (4 h), we conclude that the effectiveness of protective action of antagonist is mostly determined by the primary lipid A structure of the employed agonist.

  10. [N-allyl-Dmt1]-endomorphins are micro-opioid receptor antagonists lacking inverse agonist properties. (United States)

    Marczak, Ewa D; Jinsmaa, Yunden; Li, Tingyou; Bryant, Sharon D; Tsuda, Yuko; Okada, Yoshio; Lazarus, Lawrence H


    [N-allyl-Dmt1]-endomorphin-1 and -2 ([N-allyl-Dmt1]-EM-1 and -2) are new selective micro-opioid receptor antagonists obtained by N-alkylation with an allyl group on the amino terminus of 2',6'-dimethyl-L-tyrosine (Dmt) derivatives. To further characterize properties of these compounds, their intrinsic activities were assessed by functional guanosine 5'-O-(3-[35S]thiotriphosphate) binding assays and forskolin-stimulated cyclic AMP accumulation in cell membranes obtained from vehicle, morphine, and ethanol-treated SK-N-SH cells and brain membranes isolated from naive and morphine-dependent mice; their mode of action was compared with naloxone or naltrexone, which both are standard nonspecific opioid-receptor antagonists. [N-allyl-Dmt1]-EM-1 and -2 were neutral antagonists under all of the experimental conditions examined, in contrast to naloxone and naltrexone, which behave as neutral antagonists only in membranes from vehicle-treated cells and mice but act as inverse agonists in membranes from morphine- and ethanol-treated cells as well as morphine-treated mice. Both endomorphin analogs inhibited the naloxone- and naltrexone-elicited withdrawal syndromes from acute morphine dependence in mice. This suggests their potential therapeutic application in the treatment of drug addiction and alcohol abuse without the adverse effects observed with inverse agonist alkaloid-derived compounds that produce severe withdrawal symptoms.

  11. Aminopyrimidine derivatives as adenosine antagonists / Janke Kleynhans


    Kleynhans, Janke


    Aims of this project - The aim of this study was to design and synthesise novel 2-aminopyrimidine derivatives as potential adenosine A1 and A2A receptor antagonists. Background and rationale - Parkinson’s disease is the second most common neurodegenerative disorder (after Alzheimer’s disease) and is characterised by the selective death of the dopaminergic neurons of the nigro-striatal pathway. Distinctive motor symptoms include bradykinesia, muscle rigidity and tremor, while non-m...

  12. The Justification of Antagonistic Response to Wrongdoing


    Goldman, David Michael


    There is a strong Western tradition of opposing angry, hostile, or antagonistic reactions to wrongdoing. In the twentieth century, leaders like Mahatma Gandhi and Dr. Martin Luther King, Jr. counseled responding to wrongdoing with forgiveness and love rather than anger, hate, or vindictiveness.This ideal has taken on an exalted status in Western culture. Gandhi and King are widely regarded as moral saints. And yet sometimes antagonism seems deeply appropriate. Consider a very serious wrong: s...

  13. Antagonistic parent-offspring co-adaptation.

    Directory of Open Access Journals (Sweden)

    Mathias Kölliker

    Full Text Available BACKGROUND: In species across taxa, offspring have means to influence parental investment (PI. PI thus evolves as an interacting phenotype and indirect genetic effects may strongly affect the co-evolutionary dynamics of offspring and parental behaviors. Evolutionary theory focused on explaining how exaggerated offspring solicitation can be understood as resolution of parent-offspring conflict, but the evolutionary origin and diversification of different forms of family interactions remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: In contrast to previous theory that largely uses a static approach to predict how "offspring individuals" and "parental individuals" should interact given conflict over PI, we present a dynamic theoretical framework of antagonistic selection on the PI individuals obtain/take as offspring and the PI they provide as parents to maximize individual lifetime reproductive success; we analyze a deterministic and a stochastic version of this dynamic framework. We show that a zone for equivalent co-adaptation outcomes exists in which stable levels of PI can evolve and be maintained despite fast strategy transitions and ongoing co-evolutionary dynamics. Under antagonistic co-adaptation, cost-free solicitation can evolve as an adaptation to emerging preferences in parents. CONCLUSIONS/SIGNIFICANCE: We show that antagonistic selection across the offspring and parental life-stage of individuals favors co-adapted offspring and parental behavior within a zone of equivalent outcomes. This antagonistic parent-offspring co-adaptation does not require solicitation to be costly, allows for rapid divergence and evolutionary novelty and potentially explains the origin and diversification of the observed provisioning forms in family life.

  14. Agonistic and antagonistic estrogens in licorice root (Glycyrrhiza glabra). (United States)

    Simons, Rudy; Vincken, Jean-Paul; Mol, Loes A M; The, Susan A M; Bovee, Toine F H; Luijendijk, Teus J C; Verbruggen, Marian A; Gruppen, Harry


    The roots of licorice (Glycyrrhiza glabra) are a rich source of flavonoids, in particular, prenylated flavonoids, such as the isoflavan glabridin and the isoflavene glabrene. Fractionation of an ethyl acetate extract from licorice root by centrifugal partitioning chromatography yielded 51 fractions, which were characterized by liquid chromatography-mass spectrometry and screened for activity in yeast estrogen bioassays. One third of the fractions displayed estrogenic activity towards either one or both estrogen receptors (ERs; ERα and ERβ). Glabrene-rich fractions displayed an estrogenic response, predominantly to the ERα. Surprisingly, glabridin did not exert agonistic activity to both ER subtypes. Several fractions displayed higher responses than the maximum response obtained with the reference compound, the natural hormone 17β-estradiol (E(2)). The estrogenic activities of all fractions, including this so-called superinduction, were clearly ER-mediated, as the estrogenic response was inhibited by 20-60% by known ER antagonists, and no activity was found in yeast cells that did not express the ERα or ERβ subtype. Prolonged exposure of the yeast to the estrogenic fractions that showed superinduction did, contrary to E(2), not result in a decrease of the fluorescent response. Therefore, the superinduction was most likely the result of stabilization of the ER, yeast-enhanced green fluorescent protein, or a combination of both. Most fractions displaying superinduction were rich in flavonoids with single prenylation. Glabridin displayed ERα-selective antagonism, similar to the ERα-selective antagonist RU 58668. Whereas glabridin was able to reduce the estrogenic response of E(2) by approximately 80% at 6 × 10(-6) M, glabrene-rich fractions only exhibited agonistic responses, preferentially on ERα.

  15. Novel 3-Oxazolidinedione-6-aryl-pyridinones as Potent, Selective, and Orally Active EP3 Receptor Antagonists. (United States)

    Jin, Jian; Morales-Ramos, Angel; Eidam, Patrick; Mecom, John; Li, Yue; Brooks, Carl; Hilfiker, Mark; Zhang, David; Wang, Ning; Shi, Dongchuan; Tseng, Pei-San; Wheless, Karen; Budzik, Brian; Evans, Karen; Jaworski, Jon-Paul; Jugus, Jack; Leon, Lisa; Wu, Charlene; Pullen, Mark; Karamshi, Bhumika; Rao, Parvathi; Ward, Emma; Laping, Nicholas; Evans, Christopher; Leach, Colin; Holt, Dennis; Su, Xin; Morrow, Dwight; Fries, Harvey; Thorneloe, Kevin; Edwards, Richard


    High-throughput screening and subsequent optimization led to the discovery of novel 3-oxazolidinedione-6-aryl-pyridinones exemplified by compound 2 as potent and selective EP3 antagonists with excellent pharmacokinetic properties. Compound 2 was orally active and showed robust in vivo activities in overactive bladder models. To address potential bioactivation liabilities of compound 2, further optimization resulted in compounds 9 and 10, which maintained excellent potency, selectivity, and pharmacokinetic properties and showed no bioactivation liability in glutathione trapping studies. These highly potent, selective, and orally active EP3 antagonists are excellent tool compounds for investigating and validating potential therapeutic benefits from selectively inhibiting the EP3 receptor.

  16. Estrogen agonist/antagonist properties of dibenzyl phthalate (DBzP) based on in vitro and in vivo assays. (United States)

    Zhang, Zhaobin; Hu, Ying; Zhao, Liang; Li, Jun; Bai, Huicheng; Zhu, Desheng; Hu, Jianying


    The most commonly used phthalates have been banned or restricted for use as plasticizers in toys in some countries because of their endocrine-disrupting properties. Dibenzyl phthalate (DBzP) has been proposed as a possible alternative for the banned/restricted phthalates. In this study, the estrogen agonist/antagonist properties of DBzP were predicted by molecular docking and confirmed by yeast estrogen screen (YES) and immature mouse uterotrophic assays. The YES assay results showed a dose-dependent increase in DBzP estrogen agonist activity from 10⁻⁶ to 10⁻⁴ M, and at concentrations from 1.95×10⁻⁶ M to higher, DBzP significantly inhibited the agonist activity of 10⁻⁹ M 17β-estradiol (E₂), inhibiting 10⁻⁹ M E₂ by 74.5% at its maximum effectiveness. The in vivo estrogen agonist/antagonist activities of DBzP were demonstrated in immature mouse uterotrophic assays. The antagonist activity of DBzP inhibited E₂-induced uterine growth promoted at 40 and 400 μg/kg bw (body weight) (Pestrogen agonist/antagonist potentials of benzyl butyl phthalate (BBP) by YES, and found both were weaker than those of DBzP, suggesting DBzP would be more toxic than BBP and should not be used as an alternative plasticizer.

  17. Procognitive properties of drugs with single and multitargeting H3 receptor antagonist activities. (United States)

    Nikolic, Katarina; Filipic, Slavica; Agbaba, Danica; Stark, Holger


    The histamine H3 receptor (H3 R) is an important modulator of numerous central control mechanisms. Novel lead optimizations for H3 R antagonists/inverse agonists involved studies of structure-activity relationships, cross-affinities, and pharmacokinetic properties of promising ligands. Blockade of inhibitory histamine H3 autoreceptors reinforces histaminergic transmission, while antagonism of H3 heteroreceptors accelerates the corticolimbic liberation of acetylcholine, norepinephrine, glutamate, dopamine, serotonin and gamma-aminobutyric acid (GABA). The H3 R positioned at numerous neurotransmission crossroads indicates therapeutic applications of small-molecule H3 R modulators in a number of psychiatric and neurodegenerative diseases with various clinical candidates available. Dual target drugs displaying H3 R antagonism/inverse agonism with inhibition of acetylcholine esterase (AChE), histamine N-methyltransferase (HMT), or serotonin transporter (SERT) are novel class of procognitive agents. Main chemical diversities, pharmacophores, and pharmacological profiles of procognitive agents acting as H3 R antagonists/inverse agonists and dual H3 R antagonists/inverse agonists with inhibiting activity on AChE, HMT, or SERT are highlighted here.

  18. Antagonist capacity of Newly Isolated Strains of Pseudomonas Fluorescens against Three Important Phytopathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Reynaldo D.L. Cruz-Quiroz


    Full Text Available Problem statement: Phytopatogenic bacteria cause several damages to plants with important economical consequences. They provoke losses of product quality affecting all commercial chain of crops, for this reason, their control is a priority. Approach: We evaluated antagonist capacity of newly isolated Pseudonomas fluorescens strains against three important phytopatogenic bacteria (Clavibacter michiganensis, Xanthomonas axonopodis and Erwinia carotovora. Soils from commercial cropping of Capsicum annum L of several Mexican regions were used to isolate P. fluorescens strains. Results: Isolates producing flourescein were purified on King B agar and biochemically identified. Crude extracts with and without cells were produced in King B broths and their antagonist capacities were evaluated by the plate diffusion procedure on nutritive agar. Conclusion: Obtained results demonstrated that cell free extracts exhibited a limited antagonist capacity in comparison of those extracts with cells, which showed an excellent capacity to inhibit the growth of C. michiganensis, X. axonopodis and E. carotovora, demonstrating the intracellular nature of the bioactive metabolites associated to bacterial growth inhibition.

  19. SOCS1 mimetics and antagonists: a complementary approach to positive and negative regulation of immune function

    Directory of Open Access Journals (Sweden)

    Chulbul M. Ahmed


    Full Text Available Suppressors of cytokine signaling (SOCS are inducible intracellular proteins that play essential regulatory roles in both immune and non-immune function. Of the eight known members, SOCS1 and SOCS3 in conjunction with regulatory T cells play key roles in regulation of the immune system. Molecular tools such as gene transfections and siRNA have played a major role in our functional understanding of the SOCS proteins where a key functional domain of 12 amino acid residues called the kinase inhibitory region (KIR has been identified on SOCS1 and SOCS3. KIR plays a key role in inhibition of the JAK2 tyrosine kinase which in turn plays a key role in cytokine signaling. A peptide corresponding to KIR (SOCS1-KIR bound to the activation loop of JAK2 and inhibited tyrosine phosphorylation of STAT1α transcription factor by JAK2. Cell internalized SOCS1-KIR is a potent therapeutic in the experimental allergic encephalomyelitis (EAE mouse model of multiple sclerosis and showed promise in a psoriasis model and a model of diabetes associated cardiovascular disease. By contrast, a peptide, pJAK2(1001-1013, that corresponds to the activation loop of JAK2 is a SOCS1 antagonist. The antagonist enhanced innate and adaptive immune response against a broad range of viruses including herpes simplex virus, vaccinia virus, and an EMC picornavirus. SOCS mimetics and antagonists are thus potential therapeutics for negative and positive regulation of the immune system.

  20. Antagonistic Effects of Sodium Butyrate and N-(4-Hydroxyphenyl-retinamide on Prostate Cancer

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    Rainer Kuefer


    Full Text Available Butyrates and retinoids are promising antineoplastic agents. Here we analyzed effects of sodium butyrate and N-(4-hydroxyphenyl-retinamide (4-HPR on prostate cancer cells as monotherapy or in combination in vitro and in vivo. Sodium butyrate and 4-HPR induced concentration-dependent growth inhibition in prostate cancer cells in vitro. The isobologram analysis revealed that sodium butyrate and 4-HPR administered together antagonize effects of each other. For the in vivo studies, a water-soluble complex (4-HPR with a cyclodextrin was created. A single dose of sodium butyrate and 4-HPR showed a peak level in chicken plasma within 30 minutes. Both compounds induced inhibition of proliferation and apoptosis in xenografts of the chicken chorioallantoic membrane. Analysis of the cytotoxic effects of the drugs used in combination demonstrated an antagonistic effect on inhibition of proliferation and on induction of apoptosis. Prolonged jun N-terminal kinase phosphorylation induced by sodium butyrate and 4-HPR was strongly attenuated when both compounds were used in combination. Both compounds induced inhibition of NF-κ,B. This effect was strongly antagonized in LNCaP cells when the compounds were used in combination. These results indicate that combinational therapies have to be carefully investigated due to potential antagonistic effects in the clinical setting despite promising results of a monotherapy.


    Institute of Scientific and Technical Information of China (English)

    张建梅; 陈永红; 王晓红; 唐朝枢


    Objective. To investigate whether angiotensin II receptor antagonist and endothelin receptor antagonist can improve the nitroglycerin (Nit) tolerance in vivo. Methods. Twenty-four rats were divided into 4 groups (n =6, each): Control group, Nitroglycerin (Nit) group, Nit + bosentan group and Nit + losartan group. Nitroglycerin tolerance was induced by 2-day treatment ofnitroglycerin patch (0. 05mg/h). Angiotensin I1 receptor antagonist losartan (10mg ·kg-1·d-1) and endothe-lin receptor antagonist bosentan ( 100 mg·kg-1· d-1 ) were given by gavage for 2 days respectively. Results. The least hypotensive response to sodium nitroprusside (SNP) was observed in Nit group. The effec-tive percentages of hypotensive response to SNP were increased in both Nit + losartan group and Nit + bosentangroup compared with Nit group [(31.95±4.45) % vs (21.00±3.69) %, P <0.01and (33. 18±6. 16)% vs (21.00±3.69 ) %, P < 0. 01 , respectivelyl. The maximal vessel relaxation induced by SNP was thesame in 4 different groups but the highest EC50 (concentration which produces 50% of the maximal response toSNP) was found in tolerant group[ (34 ±10) nmol/L, P < 0. 01 ]. The ET-1 amounts in plasma and vasculartissue were markedly increased by 54% and 60% in Nit group compared with those in control group( P<0. 01). The ET-1 amounts in plasma and vascular tissue were decreased by 30% and 37% in Nit + losartangroup compared with those in Nit group ( P < 0.01 ). Conclusion. Endothelin receptor antagonist and angiotensin Ⅱ receptor antagonist could prevent against the Nit tolerance.

  2. Substituted fused bicyclic pyrrolizinones as potent, orally bioavailable hNK1 antagonists. (United States)

    Morriello, Gregori J; Mills, Sander G; Johnson, Tricia; Reibarkh, Mikhail; Chicchi, Gary; DeMartino, Julie; Kurtz, Marc; Davies, P; Tsao, K L C; Zheng, Song; Tong, Xinchun; Carlson, Emma; Townson, Karen; Tattersall, F D; Wheeldon, Alan; Boyce, Susan; Collinson, Neil; Rupniak, Nadia; Moore, Stephen; DeVita, Robert J


    Previous work on human NK(1) (hNK(1)) antagonists in which the core of the structure is a 5,5-fused pyrrolizinone has been disclosed. The structural-activity-relationship studies on simple alpha- and beta-substituted compounds of this series provided several potent and bioavailable hNK(1) antagonists that displayed excellent brain penetration as observed by their good efficacy in the gerbil foot-tapping (GFT) model assay. Several of these compounds exhibited 100% inhibition of the foot-tapping response at 0.1 and 24h with ID(50)'s of less than 1 mpk. One particular alpha-substituted compound (2b) had an excellent pharmacokinetic profile across preclinical species with reasonable in vivo functional activity and minimal ancillary activity.

  3. Synthesis, Optimization, and Evaluation of Novel Small Molecules as Antagonists of WDR5-MLL Interaction. (United States)

    Bolshan, Yuri; Getlik, Matthäus; Kuznetsova, Ekaterina; Wasney, Gregory A; Hajian, Taraneh; Poda, Gennadiy; Nguyen, Kong T; Wu, Hong; Dombrovski, Ludmila; Dong, Aiping; Senisterra, Guillermo; Schapira, Matthieu; Arrowsmith, Cheryl H; Brown, Peter J; Al-Awar, Rima; Vedadi, Masoud; Smil, David


    The WD40-repeat protein WDR5 plays a critical role in maintaining the integrity of MLL complexes and fully activating their methyltransferase function. MLL complexes, the trithorax-like family of SET1 methyltransferases, catalyze trimethylation of lysine 4 on histone 3, and they have been widely implicated in various cancers. Antagonism of WDR5 and MLL subunit interaction by small molecules has recently been presented as a practical way to inhibit activity of the MLL1 complex, and N-(2-(4-methylpiperazin-1-yl)-5-substituted-phenyl) benzamides were reported as potent and selective antagonists of such an interaction. Here, we describe the protein crystal structure guided optimization of prototypic compound 2 (K dis = 7 μM), leading to identification of more potent antagonist 47 (K dis = 0.3 μM).

  4. Screening of antagonistic activity of microorganisms against Colletotrichum acutatum and Colletotrichum gloeosporioides

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    Živković Svetlana


    Full Text Available The antagonistic activities of five biocontrol agents: Trichoderma harzianum, Gliocladium roseum, Bacillus subtilis, Streptomyces noursei and Streptomyces natalensis, were tested in vitro against Colletotrichum acutatum and Colletotrichum gloeosporioides, the causal agents of anthracnose disease in fruit crops. The microbial antagonists inhibited mycelial growth in the dual culture assay and conidial germination of Colletotrichum isolates. The two Streptomyces species exhibited the strongest antagonism against isolates of C. acutatum and C. gloeosporioides. Microscopic examination showed that the most common mode of action was antibiosis. The results of this study identify T. harzianum, G. roseum, B. subtilis, S. natalensis and S. noursei as promising biological control agents for further testing against anthracnose disease in fruits. .

  5. A high-throughput screening assay to identify bacterial antagonists against Fusarium verticillioides. (United States)

    Figueroa-López, Alejandro Miguel; Cordero-Ramírez, Jesús Damián; Quiroz-Figueroa, Francisco Roberto; Maldonado-Mendoza, Ignacio Eduardo


    A high-throughput antagonistic assay was developed to screen for bacterial isolates capable of controlling the maize fungal phytopathogen Fusarium verticillioides. This assay combines a straightforward methodology, in which the fungus is challenged with bacterial isolates in liquid medium, with a novel approach that uses the plant lectin wheat germ agglutinin (WGA) coupled to a fluorophore (Alexa-Fluor® 488) under the commercial name of WGA, Alexa Fluor® 488 conjugate. The assay is performed in a 96-well plate format, which reduces the required laboratory space and streamlines quantitation and automation of the process, making it fast and accurate. The basis of our assay is that fungal biomass can be assessed by WGA, Alexa Fluor® 488 conjugate staining, which recognizes the chitin in the fungal cell wall and thus permits the identification of potential antagonistic bacteria that inhibit fungal growth. This principle was validated by chitin-competition binding assays against WGA, Alexa Fluor® 488 conjugate; confocal laser microscopy confirmed that the fluorescent WGA, Alexa Fluor® 488 conjugate binds to the chitin of the fungal cell wall. The majority of bacterial isolates did not bind to the WGA, Alexa Fluor® 488 conjugate. Furthermore, including washing steps significantly reduced any bacterial staining to background levels, even in the rare cases where bacterial isolates were capable of binding to WGA. Confirmatory conventional agar plate antagonistic assays were also conducted to validate our technique. We are now successfully employing this large-scale antagonistic assay as a pre-screening step for potential fungal antagonists in extensive bacteria collections (on the order of thousands of isolates).

  6. Antagonist profile of ibodutant at the tachykinin NK2 receptor in guinea pig isolated bronchi. (United States)

    Santicioli, Paolo; Meini, Stefania; Giuliani, Sandro; Lecci, Alessandro; Maggi, Carlo Alberto


    In this study we have characterized the pharmacological profile of the non-peptide tachykinin NK2 receptor antagonist ibodutant (MEN15596) in guinea pig isolated main bronchi contractility. The antagonist potency of ibodutant was evaluated using the selective NK2 receptor agonist [βAla(8)]NKA(4-10)-mediated contractions of guinea pig isolated main bronchi. In this assay ibodutant (30, 100 and 300nM) induced a concentration-dependent rightward shift of the [βAla(8)]NKA(4-10) concentration-response curves without affecting the maximal contractile effect. The analysis of the results yielded a Schild-plot linear regression with a slope not different from unity (0.95, 95% c.l. 0.65-1.25), thus indicating a surmountable behaviour. The calculated apparent antagonist potency as pKB value was 8.31±0.05. Ibodutant (0.3-100nM), produced a concentration-dependent inhibition of the nonadrenergic-noncholinergic (NANC) contractile response induced by electrical field stimulation (EFS) of intrinsic airway nerves in guinea pig isolated main bronchi. At the highest concentration tested (100nM) ibodutant almost abolished the EFS-induced bronchoconstriction (95±4% inhibition), the calculated IC50 value was 2.98nM (95% c.l. 1.73-5.16nM). In bronchi from ovalbumin (OVA) sensitized guinea pigs ibodutant (100nM) did not affect the maximal contractile response to OVA, but completely prevented the slowing in the fading of the motor response induced by phosphoramidon pretreatment linked to the endogenous neurokinin A release. Altogether, the present study demonstrate that ibodutant is a potent NK2 receptor antagonist in guinea pig airways.

  7. Lactobacillus acidophilus antagonistic action against pathogenic strains inoculated in the fermented milk

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    Neila Mello Cortez


    Full Text Available With the present study aimed to evaluate the antagonistic action of Lactobacillus acidophilus front of Escherichia coli, Staphylococcus aureus and Listeria monocytogenes. In vitro tests were performed using Petri dishes with MRS agar and the milk fermented with Lactobacillus acidophilus also analyzed the chemistry and physical characteristics of the product during 35 days of storage under refrigeration. It has been observed in vitro formation of inhibition zones, ranging from 6 to 18 mm diameter, compared to the tested pathogens by lactic culture raises, indicating the possibility of producing organic acids, bacteriocins or other growth-inhibiting substances. In the fermented milk prepared, during storage, the probiotic micro-organism tested was able to inhibit the growth of E. coli O157: H7 and L. monocytogenes; and the log cycle reduction of S. aureus.

  8. Evaluation of antagonistic activity of milk fermented with kefir grains of different origins

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    João Paulo Victorino Santos


    Full Text Available In this study, the potential of kefir grains, obtained from three different towns/cities in the Southeast Region of Brazil to inhibit the growth of the five pathogenic microorganisms was evaluated. The samples showed the growth inhibition from 42.80-69.15 for Staphylococcus aureus ATCC 6538, 30.73-59.89 for Escherichia coli ATCC 11229, 44.99-73.05 for Salmonela typhi ATCC 6539, 41.45-54.18 for Listeria monocytogenes ATCC 15313 and 70.38-86.80 for Bacillus cereus RIBO 1222-173-S4. These results indicated that the kefir grains evaluated had antagonistic activity toward the different pathogens tested. The ability to inhibit, although differently depending on the regional microbiota, indicated a potential for their use as a functional food.

  9. Antagonistic Activity of Probiotic Organism Against Vibrio cholerae and Cryptococcus neoformans

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    Vidya, R.


    Full Text Available The microbes are useful in many ways in the modern world. Probiotics one of them, which refers to, acid adherence bacteria in the intestinal cells, are able to survive at low pH and produce large amount of lactic acid. The present investigation deals with the antagonistic activity of Lactobacillus acidophilus organism against pathogens. The organism was isolated from the curd sample. Identification of bacteria was done by various biochemical testing. The present study revealed that L. acidophilus inhibits Vibrio cholerae more efficiently than Streptococcus pneumoniae and Shigella dysentriae. When L. acidophilus and V. cholerae were grown together, L. acidophilus dominated the growth and competitively inhibited the growth of V. cholerae. L. acidophilus was also found to inhibit Cryptococcus neoformans.

  10. Regulating role of acetylcholine and its antagonists in inward rectified K~+ channels from guard cell protoplasts of Vicia faba

    Institute of Scientific and Technical Information of China (English)

    冷强; 花宝光; 郭玉海; 娄成后


    The inward rectified potassium current of Vicia faba guard cell protoplasts treated with acetylcholine (ACh) or the antagonists of its receptors were recorded by employing the patch clamp technique. The results show that ACh at lower concentrations increases the inward K+ current, in contrast, ACh at higher concentrations inhibits it. Treated with d-Tubocurarine (d-Tub), an antagonist of the nicotine ACh receptor (nAChR) inhibits the inward K+ current by 30%. Treated with atropine (Atr), an antagonist of the muscarine (Mus) ACh receptor (mAChR) also inhibits it by 36%. However, if guard cell protoplasts are treated with d-Tub and Atr together, the inward K+ current is inhibited by 60%-75%. Tetraethylammonium chloride (TEA), a strong inhibitor of K+ channels has no effect on the inward K+ current regulated by ACh, suggesting that there are inward K+ channels modulated by AChRs on the membrane of the guard cell protoplasts. These data demonstrate an ACh-regulated mechanism for stomatal movement.

  11. Regulating role of acetylcholine and its antagonists in inward rectified K+ channels from guard cell protoplasts of Vicia faba

    Institute of Scientific and Technical Information of China (English)


    The inward rectified potassium current of Vicia faba guard cell protoplasts treated with acetylcholine (ACh) or the antagonists of its receptors were recorded by employing the patch clamp technique. The results show that ACh at lower concentrations increases the inward K+ current, in contrast, ACh at higher concentrations inhibits it. Treated with d-Tubocurarine (d-Tub), an antagonist of the nicotine ACh receptor (nAChR) inhibits the inward K+ current by 30%. Treated with atropine (Atr), an antagonist of the muscarine (Mus) ACh receptor (mAChR) also inhibits it by 36%.However,if guard cell protoplasts are treated with d-Tub and Atr together, the inward K+ current is inhibited by 60%-75%. Tetraethylammonium chloride (TEA), a strong inhibitor of K+ channels has no effect on the inward K+ current regulated by ACh, suggesting that there are inward K+ channels modulated by AChRs on the membrane of the guard cell protoplasts. These data demonstrate an ACh-regulated mechanism for stomatal movement.


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    Full Text Available A series of laboratory and nursery experiments were conducted specifically to determine the efficacy of 85 strains of Bacillus species and 15 actinomycetes against six fungal pathogens isolated from damped-off agoho. These damping-off fungi were: Fusarium oxysporum Schet., Rhizoctonia solani Kuhn., Phytophthora parasitica Dastur, Pythium debaryanum Hesse, and two unidentified pathogens temporarily designated as Unk 1 and Unk 2. Preliminary test using the agar-plug technique revealed that 18 of the bacterial isolates could suppress two or more of the six damping-off fungi. Fusarium oxysporum was inhibited by 17 bacterial isolates, R. solani by 8 isolates, P. parasitica by 14 isolates and P. debaryanum by 15 isolates. The unidentified damping-off fungi Unk 1 and Unk 2 were inhibited by 13 and 9 isolates, respectively. Further screening using the agar-diffusion method disclosed that 10 isolates were effective antagonists with Bacillus subtilis (Code No. R060, Bacillus sp. (Code No. R071, and Streptomyces sp. (Code No. R086 as the consistent and most effective inhibitors. Application of the three most promising antagonistic bacteria as seed treatment showed that they effectively inhibited the growth of the damping-off fungi in the laboratory as exhibited by an increase in percent germination. Bacillus subtilis however, was not able to antagonize the effect of P. debaryanum in this particular experiment. Seed germination and seedling survival were likewise improved with the application of the three most promising antagonistic bacteria as seed treatment. This was shown after three months under nursery conditions. There were possible mechanisms of control by the antagonistic bacteria against the damping-off fungi. The mycelium and spores of the pathogenic fungus may have been attacked and parasitized by the antagonist when they were simultaneously grown in culture media. There must have been a competitive interaction between the two microorganisms. Any

  13. Sexually antagonistic selection in human male homosexuality.

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    Andrea Camperio Ciani

    Full Text Available Several lines of evidence indicate the existence of genetic factors influencing male homosexuality and bisexuality. In spite of its relatively low frequency, the stable permanence in all human populations of this apparently detrimental trait constitutes a puzzling 'Darwinian paradox'. Furthermore, several studies have pointed out relevant asymmetries in the distribution of both male homosexuality and of female fecundity in the parental lines of homosexual vs. heterosexual males. A number of hypotheses have attempted to give an evolutionary explanation for the long-standing persistence of this trait, and for its asymmetric distribution in family lines; however a satisfactory understanding of the population genetics of male homosexuality is lacking at present. We perform a systematic mathematical analysis of the propagation and equilibrium of the putative genetic factors for male homosexuality in the population, based on the selection equation for one or two diallelic loci and Bayesian statistics for pedigree investigation. We show that only the two-locus genetic model with at least one locus on the X chromosome, and in which gene expression is sexually antagonistic (increasing female fitness but decreasing male fitness, accounts for all known empirical data. Our results help clarify the basic evolutionary dynamics of male homosexuality, establishing this as a clearly ascertained sexually antagonistic human trait.

  14. Sexually antagonistic selection in human male homosexuality. (United States)

    Camperio Ciani, Andrea; Cermelli, Paolo; Zanzotto, Giovanni


    Several lines of evidence indicate the existence of genetic factors influencing male homosexuality and bisexuality. In spite of its relatively low frequency, the stable permanence in all human populations of this apparently detrimental trait constitutes a puzzling 'Darwinian paradox'. Furthermore, several studies have pointed out relevant asymmetries in the distribution of both male homosexuality and of female fecundity in the parental lines of homosexual vs. heterosexual males. A number of hypotheses have attempted to give an evolutionary explanation for the long-standing persistence of this trait, and for its asymmetric distribution in family lines; however a satisfactory understanding of the population genetics of male homosexuality is lacking at present. We perform a systematic mathematical analysis of the propagation and equilibrium of the putative genetic factors for male homosexuality in the population, based on the selection equation for one or two diallelic loci and Bayesian statistics for pedigree investigation. We show that only the two-locus genetic model with at least one locus on the X chromosome, and in which gene expression is sexually antagonistic (increasing female fitness but decreasing male fitness), accounts for all known empirical data. Our results help clarify the basic evolutionary dynamics of male homosexuality, establishing this as a clearly ascertained sexually antagonistic human trait.

  15. Activins and activin antagonists in hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Alev Deli; Emanuel Kreidl; Stefan Santifaller; Barbara Trotter; Katja Seir; Walter Berger; Rolf Schulte-Hermann; Chantal Rodgarkia-Dara; Michael Grusch


    In many parts of the world hepatocellular carcinoma (HCC) is among the leading causes of cancer-related mortality but the underlying molecular pathology is still insufficiently understood. There is increasing evidence that activins, which are members of the transforming growth factor β (TGFβ) superfamily of growth and differentiation factors, could play important roles in liver carcinogenesis. Activins are disulphide-linked homo-or heterodimers formed from four different β subunits termed βA, βB, βC, and βE, respectively. Activin A, the dimer of two βA subunits, is critically involved in the regulation of cell growth, apoptosis, and tissue architecture in the liver, while the hepatic function of other activins is largely unexplored so far. Negative regulators of activin signals include antagonists in the extracellular space like the binding proteins follistatin and FLRG, and at the cell membrane antagonistic co-receptors like Cripto or BAMBI. Additionally, in the intracellular space inhibitory Smads can modulate and control activin activity. Accumulating data suggest that deregulation of activin signals contributes to pathologic conditions such as chronic inflammation, fibrosis and development of cancer. The current article reviews the alterations in components of the activin signaling pathway that have been observed in HCC and discusses their potential significance for liver tumorigenesis.

  16. ETA-receptor antagonists or allosteric modulators?

    DEFF Research Database (Denmark)

    De Mey, Jo G R; Compeer, Matthijs G; Lemkens, Pieter


    The paracrine signaling peptide endothelin-1 (ET1) is involved in cardiovascular diseases, cancer and chronic pain. It acts on class A G-protein-coupled receptors (GPCRs) but displays atypical pharmacology. It binds tightly to ET receptor type A (ET(A)) and causes long-lasting effects. In resista......The paracrine signaling peptide endothelin-1 (ET1) is involved in cardiovascular diseases, cancer and chronic pain. It acts on class A G-protein-coupled receptors (GPCRs) but displays atypical pharmacology. It binds tightly to ET receptor type A (ET(A)) and causes long-lasting effects....... In resistance arteries, the long-lasting contractile effects can only be partly and reversibly relaxed by low-molecular-weight ET(A) antagonists (ERAs). However, the neuropeptide calcitonin-gene-related peptide selectively terminates binding of ET1 to ET(A). We propose that ET1 binds polyvalently to ET(A......) and that ERAs and the physiological antagonist allosterically reduce ET(A) functions. Combining the two-state model and the two-domain model of GPCR function and considering receptor activation beyond agonist binding might lead to better anti-endothelinergic drugs. Future studies could lead to compounds...

  17. Amelioration of cold injury-induced cortical brain edema formation by selective endothelin ETB receptor antagonists in mice.

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    Shotaro Michinaga

    Full Text Available Brain edema is a potentially fatal pathological condition that often occurs in stroke and head trauma. Following brain insults, endothelins (ETs are increased and promote several pathophysiological responses. This study examined the effects of ETB antagonists on brain edema formation and disruption of the blood-brain barrier in a mouse cold injury model (Five- to six-week-old male ddY mice. Cold injury increased the water content of the injured cerebrum, and promoted extravasation of both Evans blue and endogenous albumin. In the injury area, expression of prepro-ET-1 mRNA and ET-1 peptide increased. Intracerebroventricular (ICV administration of BQ788 (ETB antagonist, IRL-2500 (ETB antagonist, or FR139317 (ETA antagonist prior to cold injury significantly attenuated the increase in brain water content. Bolus administration of BQ788, IRL-2500, or FR139317 also inhibited the cold injury-induced extravasation of Evans blue and albumin. Repeated administration of BQ788 and IRL-2500 beginning at 24 h after cold injury attenuated both the increase in brain water content and extravasation of markers. In contrast, FR139317 had no effect on edema formation when administrated after cold injury. Cold injury stimulated induction of glial fibrillary acidic protein-positive reactive astrocytes in the injured cerebrum. Induction of reactive astrocytes after cold injury was attenuated by ICV administration of BQ788 or IRL-2500. These results suggest that ETB receptor antagonists may be an effective approach to ameliorate brain edema formation following brain insults.

  18. Investigating Aging-Related Changes in the Coordination of Agonist and Antagonist Muscles Using Fuzzy Entropy and Mutual Information

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    Wenbo Sun


    Full Text Available Aging alters muscular coordination patterns. This study aimed to investigate aging-related changes in the coordination of agonist and antagonist muscles from two aspects, the activities of individual muscles and the inter-muscular coupling. Eighteen young subjects and 10 elderly subjects were recruited to modulate the agonist muscle activity to track a target during voluntary isometric elbow flexion and extension. Normalized muscle activation and fuzzy entropy (FuzzyEn were applied to depict the activities of biceps and triceps. Mutual information (MI was utilized to measure the inter-muscular coupling between biceps and triceps. The agonist activation decreased and the antagonist activation increased significantly during elbow flexion and extension with aging. FuzzyEn values of agonist electromyogram (EMG were similar between the two age groups. FuzzyEn values of antagonist EMG increased significantly with aging during elbow extension. MI decreased significantly with aging during elbow extension. These results indicated increased antagonist co-activation and decreased inter-muscular coupling with aging during elbow extension, which might result from the reduced reciprocal inhibition and the recruitment of additional cortical-spinal pathways connected to biceps. Based on FuzzyEn and MI, this study provided a comprehensive understanding of the mechanisms underlying the aging-related changes in the coordination of agonist and antagonist muscles.

  19. Receptor residence time trumps drug-likeness and oral bioavailability in determining efficacy of complement C5a antagonists (United States)

    Seow, Vernon; Lim, Junxian; Cotterell, Adam J.; Yau, Mei-Kwan; Xu, Weijun; Lohman, Rink-Jan; Kok, W. Mei; Stoermer, Martin J.; Sweet, Matthew J.; Reid, Robert C.; Suen, Jacky Y.; Fairlie, David P.


    Drug discovery and translation are normally based on optimizing efficacy by increasing receptor affinity, functional potency, drug-likeness (rule-of-five compliance) and oral bioavailability. Here we demonstrate that residence time of a compound on its receptor has an overriding influence on efficacy, exemplified for antagonists of inflammatory protein complement C5a that activates immune cells and promotes disease. Three equipotent antagonists (3D53, W54011, JJ47) of inflammatory responses to C5a (3nM) were compared for drug-likeness, receptor affinity and antagonist potency in human macrophages, and anti-inflammatory efficacy in rats. Only the least drug-like antagonist (3D53) maintained potency in cells against higher C5a concentrations and had a much longer duration of action (t1/2 ~ 20 h) than W54011 or JJ47 (t1/2 ~ 1-3 h) in inhibiting macrophage responses. The unusually long residence time of 3D53 on its receptor was mechanistically probed by molecular dynamics simulations, which revealed long-lasting interactions that trap the antagonist within the receptor. Despite negligible oral bioavailability, 3D53 was much more orally efficacious than W54011 or JJ47 in preventing repeated agonist insults to induce rat paw oedema over 24 h. Thus, residence time on a receptor can trump drug-likeness in determining efficacy, even oral efficacy, of pharmacological agents.

  20. [Vascular calcifications, the hidden side effects of vitamin K antagonists]. (United States)

    Bennis, Youssef; Vengadessane, Subashini; Bodeau, Sandra; Gras, Valérie; Bricca, Giampiero; Kamel, Saïd; Liabeuf, Sophie


    Despite the availability of new oral anticoagulants, vitamin K antagonists (VKA, such as fluindione, acenocoumarol or warfarin) remain currently the goal standard medicines for oral prevention or treatment of thromboembolic disorders. They inhibit the cycle of the vitamin K and its participation in the enzymatic gamma-carboxylation of many proteins. The VKA prevent the activation of the vitamin K-dependent blood clotting factors limiting thus the initiation of the coagulation cascade. But other proteins are vitamin K-dependent and also remain inactive in the presence of VKA. This is the case of matrix Gla-protein (MGP), a protein that plays a major inhibitory role in the development of vascular calcifications. Several experimental and epidemiological results suggest that the use of the VKA could promote the development of vascular calcifications increasing thus the cardiovascular risk. This risk seems to be higher in patients with chronic kidney disease or mellitus diabetes who are more likely to develop vascular calcifications, and may be due to a decrease of the MGP activity. This review aims at summarizing the data currently available making vascular calcifications the probably underestimated side effects of VKA.

  1. Histamine and histamine receptor antagonists in cancer biology. (United States)

    Blaya, Bruno; Nicolau-Galmés, Francesca; Jangi, Shawkat M; Ortega-Martínez, Idoia; Alonso-Tejerina, Erika; Burgos-Bretones, Juan; Pérez-Yarza, Gorka; Asumendi, Aintzane; Boyano, María D


    Histamine has been demonstrated to be involved in cell proliferation, embryonic development, and tumour growth. These various biological effects are mediated through the activation of specific histamine receptors (H1, H2, H3, and H4) that differ in their tissue expression patterns and functions. Although many in vitro and in vivo studies of the modulatory roles of histamine in tumour development and metastasis have been reported, the effect of histamine in the progression of some types of tumours remains controversial; however, recent findings on the role of histamine in the immune system have shed new light on this question. This review focuses on the recent advances in understanding the roles of histamine and its receptors in tumour biology. We report our recent observations of the anti-tumoural effect of H1 histamine antagonists on experimental and human melanomas. We have found that in spite of exogenous histamine stimulated human melanoma cell proliferation, clonogenic ability and migration activity in a dose-dependent manner, the melanoma tumour growth was not modulated by in vivo histamine treatment. On the contrary, terfenadine-treatment in vitro induced melanoma cell death by apoptosis and in vivo terfenadine treatment significantly inhibited tumour growth in murine models. These observations increase our understanding of cancer biology and may inspire novel anticancer therapeutic strategies.

  2. Evaluation of H2 receptor antagonists in chronic idiopathic urticaria

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    Minocha Y


    Full Text Available H1-antagonist (hydroxyzine hydrochloride in dosage of 10 mg-25 mg thrice a day failed to elicit satisfactory response in 60 out of 170 patients of chronic idiopathic urticaria. Additional administration of H2-antagonist (cimetidine in dosage of 200 mg four times a day, in patients not responding earlier to H1-antagonist alones exhibited moderate to good improvement of various parameters of urticaria in approximately 85% patients

  3. Platelet-Activating Factor Antagonists Decrease Follicular Dendritic-Cell Stimulation of Human B Lymphocytes

    Directory of Open Access Journals (Sweden)

    Halickman Isaac


    Full Text Available Abstract Both B-lymphoblastoid cell lines and tonsillar B lymphocytes express receptors for platelet-activating factor (PAF. In lymph node germinal centres, B lymphocytes interact with follicular dendritic cells (FDCs, which present antigen-containing immune complexes to B lymphocytes. FDCs have phenotypic features that are similar to those of stromal cells and monocytes and may therefore be a source of lipid mediators. In this study, we evaluated the effects of the PAF antagonist WEB 2170 on the activation of tonsillar B lymphocytes by FDCs. FDCs were isolated from tonsils by Bovine Serum Albumin (BSA gradient centrifugation. After being cultured for 6 to 10 days, they were incubated with freshly isolated B cells in the presence or absence of the specific PAF receptor antagonist WEB 2170. B-lymphocyte proliferation was assessed by [3H]-thymidine incorporation, and immunoglobulin (Ig G and IgM secretion was assessed by enzyme-linked immunosorbent assay (ELISA. WEB 2170 (10-6 to 10-8 M inhibited [3H]-thymidine incorporation by up to 35% ± 3%. Moreover, the secretion of IgG and IgM was inhibited by up to 50% by WEB 2170 concentrations ranging from 10-6 to 10-8 M. There was no evidence of toxicity by trypan blue staining, and the addition of WEB 2170 to B cells in the absence of FDCs did not inhibit the spontaneous production of IgG or IgM. The effect of the PAF antagonist is primarily on B lymphocytes, as reverse transcription polymerase chain reaction detected little PAF receptor messenger ribonucleic acid (mRNA from FDCs. These data suggest that endogenous production of PAF may be important in the interaction of B lymphocytes with FDCs.

  4. Novel histamine H3-receptor antagonists and partial agonists with a non-aminergic structure


    Nickel, Tobias; Bauer, Ulrich; Schlicker, Eberhard; Kathmann, Markus; Göthert, Manfred; Sasse, Astrid; Stark, Holger; Schunack, Walter


    We determined the affinities of eight novel histamine H3-receptor ligands (ethers and carbamates) for H3-receptor binding sites and their agonistic/antagonistic effects in two functional H3-receptor models. The compounds differ from histamine in that the ethylamine chain is replaced by a propyloxy chain; in the three ethers mentioned below (FUB 335, 373 and 407), R is n-pentyl, 3-methylbutyl and 3,3-dimethylbutyl, respectively.The compounds monophasically inhibited [3H]-Nα-methylhistamine bin...

  5. Altered activation of the antagonist muscle during practice compromises motor learning in older adults


    Chen, Yen-Ting; Kwon, MinHyuk; Fox, Emily J.; Christou, Evangelos A.


    Aging impairs the activation of muscle; however, it remains unclear whether it contributes to deficits in motor learning in older adults. The purpose of this study was to determine whether altered activation of antagonistic muscles in older adults during practice inhibits their ability to transfer a motor task ipsilaterally. Twenty young (25.1 ± 3.9 yr; 10 men, 10 women) and twenty older adults (71.5 ± 4.8 yr; 10 men, 10 women) participated. Half of the subjects practiced 100 trials of a rapi...

  6. Mutually-Antagonistic Interactions in Baseball Networks

    CERN Document Server

    Saavedra, Serguei; McCotter, Trent; Porter, Mason A; Mucha, Peter J


    We formulate the head-to-head matchups between Major League Baseball pitchers and batters from 1954 to 2008 as a bipartite network of mutually-antagonistic interactions. We consider both the full network and single-season networks, which exhibit interesting structural changes over time. We also find that these networks exhibit a significant network structure that is sensitive to baseball's rule changes. We then study a biased random walk on the matchup networks as a simple and transparent way to compare the performance of players who competed under different conditions. We find that a player's position in the network does not correlate with his success in the random walker ranking but instead has a substantial effect on its sensitivity to changes in his own aggregate performance.

  7. Mutually-antagonistic interactions in baseball networks (United States)

    Saavedra, Serguei; Powers, Scott; McCotter, Trent; Porter, Mason A.; Mucha, Peter J.


    We formulate the head-to-head matchups between Major League Baseball pitchers and batters from 1954 to 2008 as a bipartite network of mutually-antagonistic interactions. We consider both the full network and single-season networks, which exhibit structural changes over time. We find interesting structure in the networks and examine their sensitivity to baseball’s rule changes. We then study a biased random walk on the matchup networks as a simple and transparent way to (1) compare the performance of players who competed under different conditions and (2) include information about which particular players a given player has faced. We find that a player’s position in the network does not correlate with his placement in the random walker ranking. However, network position does have a substantial effect on the robustness of ranking placement to changes in head-to-head matchups.

  8. Antagonists of IAP proteins as cancer therapeutics. (United States)

    Dynek, Jasmin N; Vucic, Domagoj


    Inhibitor of apoptosis (IAP) proteins play pivotal roles in cellular survival by blocking apoptosis, modulating signal transduction, and affecting cellular proliferation. Through their interactions with inducers and effectors of apoptosis IAP proteins can effectively suppress apoptosis triggered by diverse stimuli including death receptor signaling, irradiation, chemotherapeutic agents, or growth factor withdrawal. Evasion of apoptosis, in part due to the action of IAP proteins, enhances resistance of cancer cells to treatment with chemotherapeutic agents and contributes to tumor progression. Additionally, IAP genes are known to be subject to amplification, mutation, and chromosomal translocation in human malignancies and autoimmune diseases. In this review we will discuss the role of IAP proteins in cancer and the development of antagonists targeting IAP proteins for cancer treatment.

  9. The Attractiveness of Opposites: Agonists and Antagonists.

    LENUS (Irish Health Repository)

    O'Brien, Tony


    ABSTRACT Opioid-induced bowel dysfunction, of which constipation is the most common aspect, is a major limiting factor in the use of opioids for pain management. The availability of an oral, long-acting formulation of oxycodone and naloxone represents a highly significant development in pain management. The combination of an opioid analgesic with an opioid antagonist offers reliable pain control with a significant reduction in the burden of opioid-induced constipation. This report is adapted from paineurope 2014; Issue 3, ©Haymarket Medical Publications Ltd, and is presented with permission. paineurope is provided as a service to pain management by Mundipharma International, LTD and is distributed free of charge to healthcare professionals in Europe. Archival issues can be accessed via the website: http:\\/\\/ at which European health professionals can register online to receive copies of the quarterly publication.

  10. The NK-1 Receptor Antagonist L-732,138 Induces Apoptosis and Counteracts Substance P-Related Mitogenesis in Human Melanoma Cell Lines

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Miguel, E-mail:; Rosso, Marisa; González-Ortega, Ana [Research Laboratory on Neuropeptides, Virgen del Rocío University Hospital, Sevilla (Spain); Coveñas, Rafael [Institute of Neurosciences of Castilla y León (INCYL), Laboratory of Neuroanatomy of the Peptidergic Systems (Laboratory 14), Salamanca (Spain)


    It has been recently demonstrated that substance P (SP) and neurokinin-1 (NK-1) receptor antagonists induce cell proliferation and cell inhibition in human melanoma cells, respectively. However, the antitumor action of the NK-1 receptor antagonist L-732,138 on such cells is unknown. The aim of this study was to demonstrate an antitumor action of L-732,138 against three human melanoma cell lines (COLO 858, MEL HO, COLO 679). We found that L-732,138 elicits cell growth inhibition in a concentration dependent manner in the melanoma cells studied. Moreover, L-732,138 blocks SP mitogen stimulation. The specific antitumor action of L-732,138 occurred through the NK-1 receptor and melanoma cell death was by apoptosis. These findings indicate that the NK-1 receptor antagonist L-732,138 could be a new antitumor agent in the treatment of human melanoma.

  11. Characterization of a novel small molecule subtype specific estrogen-related receptor alpha antagonist in MCF-7 breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Michael J Chisamore

    Full Text Available BACKGROUND: The orphan nuclear receptor estrogen-related receptor alpha (ERRalpha is a member of the nuclear receptor superfamily. It was identified through a search for genes encoding proteins related to estrogen receptor alpha (ERalpha. An endogenous ligand has not been found. Novel ERRalpha antagonists that are highly specific for binding to the ligand binding domain (LBD of ERRalpha have been recently reported. Research suggests that ERRalpha may be a novel drug target to treat breast cancer and/or metabolic disorders and this has led to an effort to characterize the mechanisms of action of N-[(2Z-3-(4,5-dihydro-1,3-thiazol-2-yl-1,3-thiazolidin-2-yl idene]-5H dibenzo[a,d][7]annulen-5-amine, a novel ERRalpha specific antagonist. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrate this ERRalpha ligand inhibits ERRalpha transcriptional activity in MCF-7 cells by luciferase assay but does not affect mRNA levels measured by real-time RT-PCR. Also, ERalpha (ESR1 mRNA levels were not affected upon treatment with the ERRalpha antagonist, but other ERRalpha (ESRRA target genes such as pS2 (TFF1, osteopontin (SPP1, and aromatase (CYP19A1 mRNA levels decreased. In vitro, the ERRalpha antagonist prevents the constitutive interaction between ERRalpha and nuclear receptor coactivators. Furthermore, we use Western blots to demonstrate ERRalpha protein degradation via the ubiquitin proteasome pathway is increased by the ERRalpha-subtype specific antagonist. We demonstrate by chromatin immunoprecipitation (ChIP that the interaction between ACADM, ESRRA, and TFF1 endogenous gene promoters and ERRalpha protein is decreased when cells are treated with the ligand. Knocking-down ERRalpha (shRNA led to similar genomic effects seen when MCF-7 cells were treated with our ERRalpha antagonist. CONCLUSIONS/SIGNIFICANCE: We report the mechanism of action of a novel ERRalpha specific antagonist that inhibits transcriptional activity of ERRalpha, disrupts the constitutive

  12. Structure of the BTB domain of Keap1 and its interaction with the triterpenoid antagonist CDDO.

    Directory of Open Access Journals (Sweden)

    Anne Cleasby

    Full Text Available The protein Keap1 is central to the regulation of the Nrf2-mediated cytoprotective response, and is increasingly recognized as an important target for therapeutic intervention in a range of diseases involving excessive oxidative stress and inflammation. The BTB domain of Keap1 plays key roles in sensing environmental electrophiles and in mediating interactions with the Cul3/Rbx1 E3 ubiquitin ligase system, and is believed to be the target for several small molecule covalent activators of the Nrf2 pathway. However, despite structural information being available for several BTB domains from related proteins, there have been no reported crystal structures of Keap1 BTB, and this has precluded a detailed understanding of its mechanism of action and interaction with antagonists. We report here the first structure of the BTB domain of Keap1, which is thought to contain the key cysteine residue responsible for interaction with electrophiles, as well as structures of the covalent complex with the antagonist CDDO/bardoxolone, and of the constitutively inactive C151W BTB mutant. In addition to providing the first structural confirmation of antagonist binding to Keap1 BTB, we also present biochemical evidence that adduction of Cys 151 by CDDO is capable of inhibiting the binding of Cul3 to Keap1, and discuss how this class of compound might exert Nrf2 activation through disruption of the BTB-Cul3 interface.

  13. Diversity and Antagonistic Activity of Actinomycete Strains From Myristica Swamp Soils Against Human Pathogens

    Directory of Open Access Journals (Sweden)

    Varghese Rlnoy


    Full Text Available Under the present investigation Actinomycetes were isolated from the soils of Myristica swamps of southern Western Ghats and the antagonistic activity against different human bacterial pathogens was evaluated. Results of the present study revealed that Actinomycetes population in the soils of Myristica swamp was spatially and seasonally varied. Actinomycetes load was varied from 24×104 to 71×103, from 129×103 to 40×103 and from 31×104 to 84×103 in post monsoon, monsoon and pre monsoon respectively. A total of 23 Actinomycetes strains belonging to six genera were isolated from swamp soils. Identification of the isolates showed that most of the isolates belonged to the genus Streptomyces (11, followed by Nocardia (6, Micromonospora (3, Pseudonocardia (1, Streptosporangium (1, and Nocardiopsis (1. Antagonistic studies revealed that 91.3% of Actinomycete isolates were active against one or more tested pathogens, of that 56.52% exhibited activity against Gram negative and 86.95% showed activity against Gram positive bacteria. 39.13% isolates were active against all the bacterial pathogens selected and its inhibition zone diameter was also high. 69.5% of Actinomycetes were exhibited antibacterial activity against Listeria followed by Bacillus cereus (65.21%, Staphylococcus (60.86%, Vibrio cholera (52.17%, Salmonella (52.17% and E. coli (39.13%. The results indicate that the Myristica swamp soils of Southern Western Ghats might be a remarkable reserve of Actinomycetes with potential antagonistic activity.

  14. FGFR antagonist induces protective autophagy in FGFR1-amplified breast cancer cell. (United States)

    Chen, Yi; Xie, Xiaoyan; Li, Xinyi; Wang, Peiqi; Jing, Qian; Yue, Jiaqi; Liu, Yang; Cheng, Zhong; Li, Jingyi; Song, Haixing; Li, Guoyu; Liu, Rui; Wang, Jinhui


    Breast cancer, representing approximately 30% of all gynecological cancer cases diagnosed yearly, is a leading cause of cancer-related mortality for women. Amplification of FGFR1 is frequently observed in breast cancers and is associated with poor prognosis. Though FGFRs have long been considered as anti-cancer drug targets, and a cluster of FGFR antagonists are currently under clinical trials, the precise cellular responses under the treatment of FGFR antagonists remains unclear. Here, we show that PD166866, an FGFR1-selective inhibitor, inhibits proliferation and triggers anoikis in FGFR1-amplified breast cancer cell lines. Notably, we demonstrate that PD166866 induces autophagy in FGFR1-amplified breast cancer cell lines, while blockage of autophagy by Atg5 knockdown further enhances the anti-proliferative activities of PD166866. Moreover, mechanistic study reveals that PD166866 induces autophagy through repressing Akt/mTOR signaling pathway. Together, the present study provides new insights into the molecular mechanisms underlying the anti-tumor activities of FGFR antagonists, and may further assist the FGFRs-based drug discovery.

  15. Altered activation of the antagonist muscle during practice compromises motor learning in older adults. (United States)

    Chen, Yen-Ting; Kwon, MinHyuk; Fox, Emily J; Christou, Evangelos A


    Aging impairs the activation of muscle; however, it remains unclear whether it contributes to deficits in motor learning in older adults. The purpose of this study was to determine whether altered activation of antagonistic muscles in older adults during practice inhibits their ability to transfer a motor task ipsilaterally. Twenty young (25.1 ± 3.9 yr; 10 men, 10 women) and twenty older adults (71.5 ± 4.8 yr; 10 men, 10 women) participated. Half of the subjects practiced 100 trials of a rapid goal-directed task with ankle dorsiflexion and were tested 1 day later with elbow flexion (transfer). The rest did not perform any ankle practice and only performed the task with elbow flexion. The goal-directed task consisted of rapid movement (180 ms) to match a spatiotemporal target. For each limb, we recorded the EMG burst activity of the primary agonist and antagonist muscles. The rate of improvement during task acquisition (practice) was similar for young and older adults (P > 0.3). In contrast, only young adults were able to transfer the task to the upper limb. Specifically, young adults who practiced ankle dorsiflexion exhibited ∼30% (P movement error and ∼60% (P adults who received equal practice and young adults who did not receive any ankle dorsiflexion practice. These results provide novel evidence that the deficient motor learning in older adults may be related to a differential activation of the antagonist muscle, which compromises their ability to acquire the task during practice.

  16. Personalized medicine: theranostics (therapeutics diagnostics) essential for rational use of tumor necrosis factor-alpha antagonists. (United States)

    Bendtzen, Klaus


    With the discovery of the central pathogenic role of tumor necrosis factor (TNF)-alpha in many immunoinflammatory diseases, specific inhibition of this pleiotropic cytokine has revolutionized the treatment of patients with several non-infectious inflammatory disorders. As a result, genetically engineered anti-TNF-alpha antibody constructs now constitute one of the heaviest medicinal expenditures in many countries. All currently used TNF antagonists may dramatically lower disease activity and, in some patients, induce remission. Unfortunately, however, not all patients respond favorably, and safety can be severely impaired by immunogenicity, i.e., the ability of a drug to induce anti-drug antibodies (ADA). Assessment of ADA is therefore an important component of the evaluation of drug safety in both pre-clinical and clinical studies and in the process of developing less immunogenic and safer biopharmaceuticals. Therapeutics diagnostics, also called theranostics, i.e., monitoring functional drug levels and neutralizing ADA in the circulation, is central to more effective use of biopharmaceuticals. Hence, testing-based strategies rather than empirical dose-escalation may provide more cost-effective use of TNF antagonists as this allows therapies tailored according to individual requirements rather than the current universal approach to diagnosis. The objective of the present review is to discuss the reasons for recommending theranostics to implement an individualized use of TNF antagonists and to highlight some of the methodological obstacles that have obscured cost-effective ways of using these therapies.

  17. Low-dose prazosin in combination with 5-HT6 antagonist PRX-07034 has antipsychotic effects. (United States)

    Abraham, Renny; Nirogi, Ramakrishna; Shinde, Anil; Irupannanavar, Shantaveer


    An extensive amount of research has focused on the development of new pharmacological agents to treat schizophrenia. Varying from person to person, schizophrenia is a heterogeneous disease with symptoms of positive, negative, and cognitive deficits. PRX-07034, a 5-hydroxytryptamine6 (5-HT6) receptor antagonist has been evaluated for its potential in treating obesity and cognitive deficits. This study evaluated PRX-07034 (0.1, 0.3, and 1.0 mg/kg body mass, by intraperitoneal (i.p.) injection), in combination with a low dose of prazosin (0.3 mg/kg, i.p.), for its antipsychotic potential. The research utilized a stereotypy assay, an open field test, an object recognition task, and prepulse inhibition. Dizocilpine, a non-competitive N-methyl-d-aspartate (NMDA) antagonist, was also administered in the above-mentioned assays as a psychomimetic. The combination of PRX-07034 and prazosin alleviated stereotypy and hyperlocomotor activity while enhancing memory in an object recognition task, and reversed sensory-gating deficits induced by dizocilpine. Examination of the medial prefrontal cortex revealed that a combination of PRX-07034 and prazosin reduced the dizocilpine-mediated increase of 5-HT. These results suggest that the combination of a 5-HT6 antagonist with low doses of prazosin could have therapeutic potential in the treatment of schizophrenia.


    NARCIS (Netherlands)



    The absence of selective antagonists makes receptor characterization difficult, and largely dependent on the use of agonists. However, there has been considerable debate as to whether certain drugs acting at G protein-coupled receptors are better described as agonists, partial agonists or antagonist

  19. Gonadotrophin-releasing hormone antagonists for assisted reproductive technology

    NARCIS (Netherlands)

    Al-Inany, Hesham G.; Youssef, Mohamed A.; Ayeleke, Reuben Olugbenga; Brown, Julie; Lam, Wai Sun; Broekmans, Frank J.


    Background: Gonadotrophin-releasing hormone (GnRH) antagonists can be used to prevent a luteinizing hormone (LH) surge during controlled ovarian hyperstimulation (COH) without the hypo-oestrogenic side-effects, flare-up, or long down-regulation period associated with agonists. The antagonists direct

  20. Antagonistic and Bargaining Games in Optimal Marketing Decisions (United States)

    Lipovetsky, S.


    Game theory approaches to find optimal marketing decisions are considered. Antagonistic games with and without complete information, and non-antagonistic games techniques are applied to paired comparison, ranking, or rating data for a firm and its competitors in the market. Mix strategy, equilibrium in bi-matrix games, bargaining models with…

  1. Optimisation of GnRH antagonist use in ART

    NARCIS (Netherlands)

    Hamdine, O.


    This thesis focuses on the optimisation of controlled ovarian stimulation for IVF using exogenous FSH and GnRH antagonist co-treatment, by studying the timing of the initiation of GnRH antagonist co-medication and the role of ovarian reserve markers in optimising ovarian response and reproductive ou

  2. Functional potencies of dopamine agonists and antagonists at human dopamine D₂ and D₃ receptors. (United States)

    Tadori, Yoshihiro; Forbes, Robert A; McQuade, Robert D; Kikuchi, Tetsuro


    We measured the functional agonist potencies of dopamine agonists including antiparkinson drugs, and functional antagonist potencies of antipsychotics at human dopamine D(2) and D(3) receptors. In vitro pharmacological assessment included inhibition of forskolin-stimulated cAMP accumulation and the reversal of dopamine-induced inhibition in clonal Chinese hamster ovary cells expressing low and high densities of human dopamine D(2L) and D(2S) receptors (hD(2L)-Low, hD(2L)-High, hD(2S)-Low and hD(2S)-High, respectively) and human dopamine D(3) Ser-9 and D(3) Gly-9 receptors (hD(3)-Ser-9 and hD(3)-Gly-9, respectively). Cabergoline, bromocriptine, pergolide, (±)-7-hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT), talipexole, pramipexole, R-(+)-trans-3,4,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3-b]-1,4-oxazin-9-olhydrochloride (PD128907) and ropinirole behaved as dopamine D(2) and D(3) receptor full agonists and showed higher potencies in hD(2L)-High and hD(2S)-High compared to hD(2L)-Low and hD(2S)-Low. In hD(3)-Ser-9 and hD(3)-Gly-9 compared to hD(2L)-Low and hD(2S)-Low, dopamine, ropinirole, PD128907, and pramipexole potencies were clearly higher; talipexole and 7-OH-DPAT showed slightly higher potencies; pergolide showed slightly lower potency; and, cabergoline and bromocriptine potencies were lower. Aripiprazole acted as an antagonist in hD(2L)-Low; a low intrinsic activity partial agonist in hD(2S)-Low; a moderate partial agonist in hD(3)-Ser-9 and hD(3)-Gly-9; a robust partial agonist in hD(2L)-High; and a full agonist in hD(2S)-High. Amisulpride, sulpiride and perphenazine behaved as preferential antagonists; and chlorpromazine and asenapine behaved as modest preferential antagonists; whereas fluphenazine, haloperidol, and blonanserin behaved as non-preferential antagonists in hD(2S)-Low and hD(2S)-High compared to hD(3)-Ser-9 and hD(3)-Gly-9. These findings may help to elucidate the basis of therapeutic benefit observed with these drugs, with

  3. Early, but not late therapy with a vasopressin V-1a-antagonist ameliorates the development of renal damage after 5/6 nephrectomy

    NARCIS (Netherlands)

    Windt, Willemijn A. K. M.; Tahara, Atsua; Kluppel, Alex C. A.; de Zeeuw, Dick; Henning, Robert H.; van Dokkum, Richard P. E.


    Introduction. Vasopressin, mainly through the VIA-receptor, is thought to be a major player in the maintenance of hyperfiltration. Its inhibition could therefore lead to a decrease in progression of chronic renal failure. To this end, the effect of the vasopressin V-1a-receptor-selective antagonist,

  4. Early, but not late therapy with a vasopressin V1a-antagonist ameliorates the development of renal damage after 5/6 nephrectomy

    NARCIS (Netherlands)

    Windt, Willemijn A K M; Tahara, Atsua; Kluppel, Alex C A; de Zeeuw, Dick; Henning, Robert H; van Dokkum, Richard P E


    INTRODUCTION: Vasopressin, mainly through the V1a-receptor, is thought to be a major player in the maintenance of hyperfiltration. Its inhibition could therefore lead to a decrease in progression of chronic renal failure. To this end, the effect of the vasopressin V1a-receptor-selective antagonist,

  5. Histamine and histamine-receptor antagonists modify gene expression and biosynthesis of interferon gamma in peripheral human blood mononuclear cells and in CD19-depleted cell subsets

    NARCIS (Netherlands)

    Horváth, B V; Szalai, C; Mándi, Y; László, V; Radvány, Z; Darvas, Z; Falus, A


    The effect of histamine and histamine antagonists was examined on gene expression and biosynthesis of bacterial endotoxin (LPS) induced interferon gamma (IFNgamma) both in human peripheral mononuclear cells (PMBC) and in T-cell enriched fractions. We found, that histamine inhibited the LPS induced t

  6. Draft Genome Sequence of Rhizobium sp. Strain TBD182, an Antagonist of the Plant-Pathogenic Fungus Fusarium oxysporum, Isolated from a Novel Hydroponics System Using Organic Fertilizer (United States)

    Fujiwara, Kazuki; Someya, Nobutaka; Shinohara, Makoto


    ABSTRACT Rhizobium sp. strain TBD182, isolated from a novel hydroponics system, is an antagonistic bacterium that inhibits the mycelial growth of Fusarium oxysporum but does not eliminate the pathogen. We report the draft genome sequence of TBD182, which may contribute to elucidation of the molecular mechanisms of its fungistatic activity. PMID:28302768

  7. Up-regulation of reciprocal inhibition by explosive strength training

    DEFF Research Database (Denmark)

    Geertsen, Svend Sparre; Jensen, Jesper Lundbye; Nielsen, Jens Bo

    At the onset of dorsiflexion disynaptic reciprocal inhibition (DRI) of soleus motoneurones is increased in order to prevent activation of the antagonistic plantarflexors. This is caused by descending facilitation of transmission in the DRI pathway. Since the risk of eliciting stretch reflexes...

  8. Dihydromorphine-peptide hybrids with delta receptor agonistic and mu receptor antagonistic actions

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.B.; Medzihradsky, F.; Woods, J.H.


    The actions of two morphine derivatives with short peptide side chains were evaluated upon the contraction of the isolated mouse vas deferens and upon displacement of /sup 3/H-etorphine from rat brain membranes. NIH-9833 (N-(6,14-endoetheno-7,8-dihydromorphine-7-alpha-carbonyl)-L-phenylalanyl-L-leucine ethyl ester HCl) was a potent agonist upon the vas deferens. Its EC50 for inhibition of the twitch was 1.2 +/- 0.1 nM. Both naltrexone (10/sup -7/ M) a relatively nonselective opioid antagonist, and ICI-174864 (10/sup -/' M) a highly selective delta receptor antagonist, blocked the actions of NIH-9833 which indicates that this drug is a delta receptor agonist. In contrast, NIH-9835 (N-(6,14-endoetheno-7,8-dihydromorphine-7-alpha-carbonyl)-L-glycyl-L-phenylalanyl-L-leucine ethyl ester HCl), which differs from NIH-9835 by the presence of a single amino acid residue, was devoid of opioid agonistic activity but was a potent antagonist of the inhibitory actions on the vas deferens of morphine and sufentanil. NIH-9833 and NIH-9835 were potent displacers of /sup 3/H-etorphine from rat cerebral membranes with EC50's of 0.58 nM and 1.7 nM, respectively. The observation that addition of a single glycyl group changes a dihydromorphine-peptide analog from a potent delta receptor agonist to an equally potent mu receptor antagonist suggests that the two receptor sites might be structurally quite similar.

  9. Serotonin receptor antagonists discriminate between PKA- and PKC-mediated plasticity in aplysia sensory neurons. (United States)

    Dumitriu, Bogdan; Cohen, Jonathan E; Wan, Qin; Negroiu, Andreea M; Abrams, Thomas W


    Highly selective serotonin (5-hydroxytryptamine, 5-HT) receptor antagonists developed for mammals are ineffective in Aplysia due to the evolutionary divergence of neurotransmitter receptors and because the higher ionic strength of physiological saline for marine invertebrates reduces antagonist affinity. It has therefore been difficult to identify antagonists that specifically block individual signaling cascades initiated by 5-HT. We studied two broad-spectrum 5-HT receptor antagonists that have been characterized biochemically in Aplysia CNS: methiothepin and spiperone. Methiothepin is highly effective in inhibiting adenylyl cyclase (AC)-coupled 5-HT receptors in Aplysia. Spiperone, which blocks phospholipase C (PLC)-coupled 5-HT receptors in mammals, does not block AC-coupled 5-HT receptors in Aplysia. In electrophysiological studies, we explored whether methiothepin and spiperone can be used in parallel to distinguish between the AC-cAMP and PLC-protein kinase C (PKC) modulatory cascades that are initiated by 5-HT. 5-HT-induced broadening of the sensory neuron action potential in the presence of tetraethylammonium/nifedipine, which is mediated by modulation of the S-K+ currents, was used an assay for the AC-cAMP cascade. Spike broadening initiated by 5 microM 5-HT was unaffected by 100 microM spiperone, whereas it was effectively blocked by 100 microM methiothepin. Facilitation of highly depressed sensory neuron-to-motor neuron synapses by 5-HT was used as an assay for the PLC-PKC cascade. Spiperone completely blocked facilitation of highly depressed synapses by 5 microM 5-HT. In contrast, methiothepin produced a modest, nonsignificant, reduction in the facilitation of depressed synapses. Interestingly, these experiments revealed that the PLC-PKC cascade undergoes desensitization during exposure to 5-HT.

  10. Vaninolol: a new selective beta 1-adrenoceptor antagonist derived from vanillin. (United States)

    Wu, B N; Hwang, T L; Liao, C F; Chen, I J


    The beta-adrenoceptor blocking properties of vaninolol ((+/-)4-[4'-(2-hydroxy-3-tert-butyl-aminopropoxy)-3'-methoxyphenyl]- 3-buten-2-one), derived from vanillin, were first investigated under in vivo and in vitro conditions. Vaninolol (0.1, 0.5, 1.0 mg/kg, i.v.), as well as propranolol, produced a dose-dependent bradycardia response and a sustained pressor action in urethane-anesthetized normotensive rats. Vaninolol inhibited the tachycardia effects induced by (-)isoproterenol, but had no blocking effect on the arterial pressor responses induced by phenylephrine. These findings suggested that vaninolol possessed beta-adrenergic blocking activity, but was without alpha-adrenergic blocking activity. In isolated guinea-pig tissues, vaninolol antagonized (-)isoproterenol-induced positive inotropic and chronotropic effects of the atria and tracheal relaxation responses in a concentration-dependent manner. The parallel shift to the right of the concentration-response curve of (-)isoproterenol suggested that vaninolol was a beta-adrenoceptor competitive antagonist. The effect of vaninolol was more potent on the atria than on tracheal tissues, indicating it had some beta 1-adrenoceptor selectivity. On the other hand, the order of the hydrophilicity was atenolol > vaninolol > propranolol. In addition, vaninolol had a mild direct cardiac depression at high concentrations and was without intrinsic sympathomimetic activity (ISA). Furthermore, binding characteristics of vaninolol and other beta-adrenoceptor antagonists were evaluated in [3H]dihydroalprenolol binding to guinea-pig ventricular membranes. The order of potency of beta-adrenoceptor antagonists in competing for the binding sites was (-)propranolol > vaninolol > or = atenolol. In conclusion, vaninolol was found to be a selective beta 1-adrenoceptor antagonist with relatively low lipophilicity in comparison with propranolol, devoid of ISA, and had a mild myocardial depressant effect.

  11. Anxiolytic-like effects of mGlu1 and mGlu5 receptor antagonists in rats. (United States)

    Pietraszek, Małgorzata; Sukhanov, Ilia; Maciejak, Piotr; Szyndler, Janusz; Gravius, Andreas; Wisłowska, Aleksandra; Płaźnik, Adam; Bespalov, Anton Y; Danysz, Wojciech


    The purpose of the present study was to compare anxiolytic activity of the metabotropic glutamate receptor 1 (mGlu) antagonist, EMQMCM ((3-ethyl-2-methyl-quinolin-6-yl)-(4-methoxy-cyclohexyl)-methanone methanesulfonate) and the mGlu5 receptor antagonist MTEP ([(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine) and MPEP (2-methyl-6-(phenylethynyl)pyridine) in animal models of anxiety. In the elevated plus maze, diazepam (1 mg/kg), but not the mGlu1 or mGlu5 receptor antagonists induced anxiolytic-like effects. Meanwhile, MTEP (2.5 and 5 mg/kg), EMQMCM (5 mg/kg), and diazepam (2 mg/kg) all significantly inhibited fear potentiated startle. In the contextual fear conditioning test, MTEP (1.25 and 2.5 but not 5 mg/kg) and EMQMCM (0.6 to 5 mg/kg) attenuated freezing responding. In the Geller-Seifter conflict test, MPEP (1 and 3 mg/kg), MTEP (3 mg/kg), chlordiazepoxide (10 and 20 mg/kg) and midazolam (1 mg/kg) all facilitated punished responding, while ECMQCM failed to produce any significant effects up to 3 mg/kg dose. To summarise, the present data further support a significant anxiolytic potential of group I mGlu receptor antagonists, while suggesting the effects of mGlu1 receptor antagonists may depend on the experimental procedure and may be qualitatively different from those of mGlu5 receptor antagonists.

  12. Screening and identification of receptor antagonist for shiga toxin from random peptides displayed on filamentous bacteriophages

    Institute of Scientific and Technical Information of China (English)

    韩照中; 苏国富; 黄翠芬


    The bacteriophage clones which can bind with shiga toxin B subunit (StxB) and inhibit cytotoxicity of shiga toxin were obtained by using antibody capturing method from a 15-mer random peptide library displayed on the surface of bacteriophage fd. Among them, one peptide encoded by the random DNA region of a selected bacteriophage (A12) was synthesized and tested in vitro and in vivo, where the peptide competed with the receptor of shiga toxin to bind StxB, and inhibited the cytotoxicity and enterotoxicity of shiga toxin. The peptide can also block other apparently unrelated StxB binding bacteriophage (A3), which suggests that there are overlapping StxB interaction sites for those ligands with different sequences. The results provide a demonstration of bacteriophage display to screen peptide ligands for a small and/or unable biotinylated molecule by antibodies-capturing strategy, and take the lead for the development of receptor antagonists for shiga toxin.

  13. The estrogen antagonist ICI 182,780 reduces cancellous bone volume in female rats. (United States)

    Gallagher, A; Chambers, T J; Tobias, J H


    Although estrogen is thought to protect the skeleton by inhibiting bone resorption, we have also found that in the rat, estrogen stimulates cancellous bone formation. However, the extent to which the various skeletal actions of estrogen are mediated by classical estrogen receptors remains unclear. Although estrogen receptor antagonists such as tamoxifen have been used to study this question, interpretation of the results is complicated by the fact that this agent also acts as a partial estrogen agonist. However, the recent development of estrogen antagonists devoid of agonist activity provides an opportunity to explore this question further. We, therefore, investigated the effect of administration of the pure estrogen antagonist ICI 182,780 on the skeleton of adult female rats. We found that ICI 182,780 reduced bone volume at the proximal tibial metaphysis by approximately 30%, associated with an increase in osteoclast surface. We then investigated the effect of ICI 182,780 on the anabolic action of estrogen. We used ovariectomized rats treated with 3-amino-1-hydroxypropylidene-1-bisphosphonate to inhibit bone resorption, thereby preventing any increase in bone formation as a result of the stimulation of bone resorption due to estrogen deficiency. 17 beta-Estradiol (1 micrograms/kg) stimulated cancellous bone formation in such animals by approximately 8-fold; this increase was abolished when ICI 182,780 was also given. In contrast, ICI 182,780 affected neither longitudinal nor periosteal tibial growth in either intact animals or ovariectomized rats given estradiol or vehicle. We conclude that ICI 182,780 reduces cancellous bone volume in the rat by antagonizing estrogen's actions on bone formation and resorption, suggesting that these processes are both mediated by classical estrogen receptors.

  14. The Hypocretin/Orexin Antagonist Almorexant Promotes Sleep Without Impairment of Performance in Rats

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    Stephen R Morairty


    Full Text Available The hypocretin receptor (HcrtR antagonist almorexant (ALM has potent hypnotic actions but little is known about neurocognitive performance in the presence of ALM. HcrtR antagonists are hypothesized to induce sleep by disfacilitation of wake-promoting systems whereas GABAA receptor modulators such as zolpidem (ZOL induce sleep through general inhibition of neural activity. To test the hypothesis that less functional impairment results from HcrtR antagonist-induced sleep, we evaluated the performance of rats in the Morris Water Maze in the presence of ALM vs. ZOL. Performance in spatial reference memory (SRM and spatial working memory (SWM tasks were assessed during the dark period after equipotent sleep-promoting doses (100 mg/kg, po following undisturbed and sleep deprivation (SD conditions. ALM-treated rats were indistinguishable from vehicle (VEH-treated rats for all SRM performance measures (distance travelled, latency to enter, time within, and number of entries into, the target quadrant after both the undisturbed and 6 h SD conditions. In contrast, rats administered ZOL showed impairments in all parameters measured compared to VEH or ALM in the undisturbed conditions. Following SD, ZOL-treated rats also showed impairments in all measures. ALM-treated rats were similar to VEH-treated rats for all SWM measures (velocity, time to locate the platform and success rate at finding the platform within 60 s after both the undisturbed and SD conditions. In contrast, ZOL-treated rats showed impairments in velocity and in the time to locate the platform. Importantly, ZOL rats only completed the task 23-50% of the time while ALM and VEH rats completed the task 79-100% of the time. Thus, following equipotent sleep-promoting doses, ZOL impaired rats in both memory tasks while ALM rats performed at levels comparable to VEH rats. These results are consistent with the hypothesis that less impairment results from HcrtR antagonism than from GABAA


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    Full Text Available Rice is an important crop, widely affected by quite a number of diseases that results in higher yield losses. Among the fungal diseases, blast incited by Pyricularia oryzae is a major disease. The biological method of plant disease management seems to be an alternative to chemical fungicides in managing the blast disease. A new bio control agent viz., Serratia marcescens appears to be an ideal agent for the control of P. oryzae, because it produces chitinolytic enzymes which causes degradation of the fungal cell walls, induction of plant defence reaction and certain antifungal low molecular weight molecules. A study was undertaken to investigate the effect of a new bio control agent like S. marcescens against P. oryzae. The talc based formulation of S. marcescens (@ 1.0, 1.5, 2.0 and 2.5 kg/ha was sprayed on old IR 50 rice plants in fields. Out of the six-bio protectants tested, S. marcescens was found very effective against P. oryzae under in vitro conditions. S. marcescens could be isolated from shoots as well as roots emerging from the treated seeds and the plant parts from treated seeds inhibited P. oryzae. The antagonist S. marcescens survived in the phyllosphere even 80 days after spray. The results revealed that rice blast control was achieved by spraying S. marcescens @ 1.0 kg/ha. The increasing dose of talc-based inoculum when applied on foliage increased the phyllosphere population of S. marcescens and controlled rice blast. The maximum disease control was achieved when inoculum was applied at 2.5 kg/ha.

  16. Synthesis and evaluation of orally active small molecule HIV-1 Nef antagonists. (United States)

    Emert-Sedlak, Lori A; Loughran, H Marie; Shi, Haibin; Kulp, John L; Shu, Sherry T; Zhao, Jielu; Day, Billy W; Wrobel, Jay E; Reitz, Allen B; Smithgall, Thomas E


    The HIV-1 Nef accessory factor enhances viral replication and promotes immune system evasion of HIV-infected cells, making it an attractive target for drug discovery. Recently we described a novel class of diphenylpyrazolodiazene compounds that bind directly to Nef in vitro and inhibit Nef-dependent HIV-1 infectivity and replication in cell culture. However, these first-generation Nef antagonists have several structural liabilities, including an azo linkage that led to poor oral bioavailability. The azo group was therefore replaced with either a one- or two-carbon linker. The resulting set of non-azo analogs retained nanomolar binding affinity for Nef by surface plasmon resonance, while inhibiting HIV-1 replication with micromolar potency in cell-based assays without cytotoxicity. Computational docking studies show that these non-azo analogs occupy the same predicted binding site within the HIV-1 Nef dimer interface as the original azo compound. Computational methods also identified a hot spot for inhibitor binding within this site that is defined by conserved HIV-1 Nef residues Asp108, Leu112, and Pro122. Pharmacokinetic evaluation of the non-azo B9 analogs in mice showed that replacement of the azo linkage dramatically enhanced oral bioavailability without substantially affecting plasma half-life or clearance. The improved oral bioavailability of non-azo diphenylpyrazolo Nef antagonists provides a starting point for further drug lead optimization in support of future efficacy testing in animal models of HIV/AIDS.

  17. Effect of SDF-1/Cxcr4 Signaling Antagonist AMD3100 on Bone Mineralization in Distraction Osteogenesis. (United States)

    Xu, Jia; Chen, Yuanfeng; Liu, Yang; Zhang, Jinfang; Kang, Qinglin; Ho, Kiwai; Chai, Yimin; Li, Gang


    Distraction osteogenesis (DO) is a widely applied technique in orthopedics surgery, which involves rapid stem cell migration, homing, and differentiation. Interactions between the chemokine receptor Cxcr4 and its ligand, stromal derived factor-1 (SDF-1), regulate hematopoietic stem cell trafficking to the ischemic area and induce their subsequent differentiation. Here, we examined SDF-1 expression and further investigated the role of SDF-1/Cxcr4 signaling antagonist AMD3100 during bone regeneration in rat DO model. The results showed that expression levels of SDF-1 and osteogenic genes were higher in DO zones than in the fracture zones, and SDF-1 expression level was the highest at the termination of the distraction phase. Radiological, mechanical, and histological analyses demonstrated that the local administration of AMD3100 (400 μM) to DO rats significantly inhibited new bone formation. In the rat bone marrow mesenchymal stem cells culture, comparing to the group treated with osteogenic induction medium, AMD3100 supplement led to a considerable decrease in the expression of alkaline phosphatase and early osteogenic marker genes. However, the amount of calcium deposits in rat MSCs did not differ between the groups. Therefore, our study demonstrated that the DO process induced higher expression of SDF-1, which collated to rapid induction of callus formation. Local application of SDF-1/Cxcr4 signaling antagonist AMD3100 significantly inhibited bone mineralization and osteogenesis in DO, which may represent a potential therapeutic approach to the enhancement of bone consolidation in patients undergoing DO.

  18. Salvianolic Acid A, as a Novel ETA Receptor Antagonist, Shows Inhibitory Effects on Tumor in Vitro. (United States)

    Zhang, Qiao; Wang, Shifeng; Yu, Yangyang; Sun, Shengnan; Zhang, Yuxin; Zhang, Yanling; Yang, Wei; Li, Shiyou; Qiao, Yanjiang


    Endothelin-1 (ET-1) autocrine and paracrine signaling modulate cell proliferation of tumor cells by activating its receptors, endothelin A receptor (ETAR) and endothelin B receptor (ETBR). Dysregulation of ETAR activation promotes tumor development and progression. The potential of ETAR antagonists and the dual-ETAR and ETBR antagonists as therapeutic approaches are under preclinical and clinical studies. Salvianolic acid A (Sal A) is a hydrophilic polyphenolic derivative isolated from Salvia miltiorrhiza Bunge (Danshen), which has been reported as an anti-cancer and cardio-protective herbal medicine. In this study, we demonstrate that Sal A inhibits ETAR activation induced by ET-1 in both recombinant and endogenous ETAR expression cell lines. The IC50 values were determined as 5.7 µM in the HEK293/ETAR cell line and 3.14 µM in HeLa cells, respectively. Furthermore, our results showed that Sal A suppressed cell proliferation and extended the doubling times of multiple cancer cells, including HeLa, DU145, H1975, and A549 cell lines. In addition, Sal A inhibited proliferation of DU145 cell lines stimulated by exogenous ET-1 treatment. Moreover, the cytotoxicity and cardio-toxicity of Sal A were assessed in human umbilical vein endothelial cells (HUVEC) and Human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs), which proved that Sal A demonstrates no cytotoxicity or cardiotoxicity. Collectively, our findings indicate that Sal A is a novel anti-cancer candidate through targeting ETAR.

  19. Alpha 2-adrenoceptor antagonist potencies of two hydroxylated metabolites of yohimbine. (United States)

    Berlan, M.; Le Verge, R.; Galitzky, J.; Le Corre, P.


    1. The alpha 2-adrenoceptor antagonist capacities of two hydroxylated metabolites of yohimbine in man (10-OH-yohimbine and 11-OH-yohimbine) were investigated on the alpha 2-adrenoceptors of human platelets and adipocytes and compared to those of yohimbine. 2. Yohimbine and 11-OH-yohimbine exhibited similar alpha 2-adrenoceptor affinity in biological studies i.e. inhibition of adrenaline-induced platelet aggregation and inhibition of UK14304-induced antilipolysis in adipocytes. 3. Yohimbine and the two metabolites displaced [3H]-RX 821002 binding with equivalent affinities in platelet and adipocyte membranes with the following order of potency: yohimbine > 11-OH-yohimbine > 10-OH-yohimbine. However, when binding studies were carried out in binding buffer supplemented with 5% albumin, the apparent affinity of yohimbine was reduced about 10 fold and was similar to that of 11-OH-yohimbine. 4. Yohimbine and its metabolites were bound to different extents to plasma proteins, the bound fraction being 82%, 43% and 32% respectively for yohimbine, 11-OH-yohimbine and 10-OH-yohimbine. 5. These results show that the main hydroxylated metabolite of yohimbine in man (11-OH-yohimbine) possesses alpha 2-adrenoceptor antagonist properties. The discrepancies found in binding studies (i.e. 10 fold lower affinity of 11-OH-yohimbine than yohimbine for alpha 2-adrenoceptors but similar capacities in blocking biological alpha 2-adrenoceptor effects in cells) are attributable to the higher degree of binding of yohimbine to plasma protein. PMID:8097957

  20. Antiasthmatic activity of a novel thromboxane A2 antagonist, S-1452, in guinea pigs. (United States)

    Arimura, A; Asanuma, F; Kurosawa, A; Harada, M


    We examined the effect of a potent thromboxane (Tx) A2 receptor antagonist, calcium (1R, 2S, 3S, 4S)-(5Z)-7-(((phenylsulfonyl)amino)bicyclo[2.2.1] hept-2-yl)-5-heptenoate dihydrate (S-1452), on antigen- and various allergic-spasmogen-induced contractions of guinea pig lung parenchymal strips and on the increase in insufflation pressure, an index of bronchoconstriction, in anesthetized guinea pigs. In isolated guinea pig lung parenchymal strips, S-1452 showed competitive antagonism of the contractile activity of U-46619, a TxA2 mimetic, with a pA2 value of 8.9. The compound also inhibited the contraction induced by prostaglandin (PG) D2 and PGF2 alpha, but a TxA2 synthetase inhibitor, OKY-046, did not. In contrast, both drugs inhibited not only leukotriene (LT) D4-induced contraction but also antigen-induced contraction in the presence of a histamine antagonist. In anesthetized guinea pigs, oral administration of S-1452 markedly inhibited the bronchoconstrictions induced by intravenous injection of U-46619, PGD2, PGF2 alpha, LTD4 and platelet-activating factor (PAF) with ED50 values of 0.006, 0.031, 0.112, 0.033 and 0.115 mg/kg, respectively, but OKY-046 inhibited only that by LTD4 and PAF. Additionally, bronchoconstriction following intravenous injection of antigen was almost completely suppressed by S-1452 (0.1 mg/kg) and partially by OKY-046 (300 mg/kg) in passively sensitized guinea pigs which were treated with diphenydramine and propranolol. The inhibitory effect of S-1452 against U-46619-induced broncho-constriction persisted up to 7 h after oral administration.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Fine Tuning of a Type 1 Interferon Antagonist.

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    Victoria Urin

    Full Text Available Type I interferons are multi-potent cytokines that serve as first line of defense against viruses and other pathogens, posses immunomudolatory functions and elicit a growth inhibitory response. In recent years it has been shown that interferons are also detrimental, for example in lupus, AIDS, tuberculosis and cognitive decline, highlighted the need to develop interferon antagonists. We have previously developed the antagonist IFN-1ant, with much reduced binding to the IFNAR1 receptor and enhanced binding to IFNAR2. Here, we further tune the IFN-1ant by producing three additional antagonists based on IFN-1ant but with altered activity profiles. We show that in all three cases the antiproliferative activity of interferons is blocked and the induction of gene transcription of immunomudolatory and antiproliferative associated genes are substantially decreased. Conversely, each of the new antagonists elicits a different degree of antiviral response, STAT phosphorylation and related gene induction. Two of the new antagonists promote decreased activity in relation to the original IFN-1ant, while one of them promotes increased activity. As we do not know the exact causes of the detrimental effects of IFNs, the four antagonists that were produced and analyzed provide the opportunity to investigate the extent of antagonistic and agonistic activity optimal for a given condition.

  2. Nalmefene: radioimmunoassay for a new opioid antagonist. (United States)

    Dixon, R; Hsiao, J; Taaffe, W; Hahn, E; Tuttle, R


    A specific radioimmunoassay (RIA) has been developed for the quantitation of a new opioid antagonist, nalmefene, in human plasma. The method employs a rabbit antiserum to an albumin conjugate of naltrexone-6-(O-carboxymethyl)oxime and [3H]naltrexone as the radioligand. Assay specificity was achieved by extraction of nalmefene from plasma at pH 9 into ether prior to RIA. The procedure has a limit of sensitivity of 0.2 ng/mL of nalmefene using a 0.5-mL sample of plasma for analysis. The intra- and interassay coefficients of variation did not exceed 5.6 and 11%, respectively. The specificity of the RIA was established by demonstrating excellent agreement (r = 0.99) with a less sensitive and more time consuming HPLC procedure in the analysis of clinical plasma samples. The use of the RIA for the pharmacokinetic evaluation of nalmefene is illustrated with plasma concentration profiles of the drug in humans following intravenous and oral administration.

  3. Multiple Targeting Approaches on Histamine H3 Receptor Antagonists. (United States)

    Khanfar, Mohammad A; Affini, Anna; Lutsenko, Kiril; Nikolic, Katarina; Butini, Stefania; Stark, Holger


    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.

  4. Multiple Targeting Approaches on Histamine H3 Receptor Antagonists

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    Mohammad eKhanfar


    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.

  5. Identification of a novel conformationally constrained glucagon receptor antagonist. (United States)

    Lee, Esther C Y; Tu, Meihua; Stevens, Benjamin D; Bian, Jianwei; Aspnes, Gary; Perreault, Christian; Sammons, Matthew F; Wright, Stephen W; Litchfield, John; Kalgutkar, Amit S; Sharma, Raman; Didiuk, Mary T; Ebner, David C; Filipski, Kevin J; Brown, Janice; Atkinson, Karen; Pfefferkorn, Jeffrey A; Guzman-Perez, Angel


    Identification of orally active, small molecule antagonists of the glucagon receptor represents a novel treatment paradigm for the management of type 2 diabetes mellitus. The present work discloses novel glucagon receptor antagonists, identified via conformational constraint of current existing literature antagonists. Optimization of lipophilic ligand efficiency (LLE or LipE) culminated in enantiomers (+)-trans-26 and (-)-trans-27 which exhibit good physicochemical and in vitro drug metabolism profiles. In vivo, significant pharmacokinetic differences were noted with the two enantiomers, which were primarily driven through differences in clearance rates. Enantioselective oxidation by cytochrome P450 was ruled out as a causative factor for pharmacokinetic differences.

  6. New potential uroselective NO-donor alpha1-antagonists. (United States)

    Boschi, Donatella; Tron, Gian Cesare; Di Stilo, Antonella; Fruttero, Roberta; Gasco, Alberto; Poggesi, Elena; Motta, Gianni; Leonardi, Amedeo


    A recent uroselective alpha(1)-adrenoceptor antagonist, REC15/2739, has been joined with nitrooxy and furoxan NO-donor moieties to give new NO-donor alpha(1)-antagonists. All the compounds studied proved to be potent and selective ligands of human cloned alpha(1a)-receptor subtype. Derivatives 6 and 7 were able to relax the prostatic portion of rat vas deferens contracted by (-)-noradrenaline because of both their alpha(1A)-antagonist and their NO-donor properties.

  7. Screening and Identification of Cotton Verticillium Wilt Antagonistic Bacteria Strain 7-30%棉花黄萎病拮抗细菌7-30菌株的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    雷白时; 姜军坡; 王伟; 张冬冬; 王全; 朱宝成


    [Objective]The aim of this study was to screen the antagonistic spore-forming bacteria of Verticillium dahliae and identify its physiological and biochemical characteristics. [Method]Taking the cotton verticillium wilt pathogen Verticillium dahliae V-190 as the test microorganism, the antagonistic spore-forming bacteria were screened. Through the preliminary screening and secondary screening, an antagonistic bacteria strain 7-30 with stronger antibacterial activity was obtained, and its morphological characteristics, physiological and biochemical characteristics were also identified. [Result]84 antagonistic bacteria strains were isolated from soil in various places by the preliminary screening. Especially, 18 strains with better antagonistic ability were screened again, so an antagonistic bacteria strain 7-30 with the diameter of inhibition zone 18.9 mm and stronger antibacterial activity was obtained. According to its morphological characteristics, physiological and biochemical characteristics, the antagonistic bacteria strain 7-30 was identified as Bacillus subtilis primarily. [Conclusion]The strain 7-30 was obtained as the antagonistic spore-forming bacteria of Verticillium dahliae.

  8. Cerebellar cortical inhibition and classical eyeblink conditioning. (United States)

    Bao, Shaowen; Chen, Lu; Kim, Jeansok J; Thompson, Richard F


    The cerebellum is considered a brain structure in which memories for learned motor responses (e.g., conditioned eyeblink responses) are stored. Within the cerebellum, however, the relative importance of the cortex and the deep nuclei in motor learning/memory is not entirely clear. In this study, we show that the cerebellar cortex exerts both basal and stimulus-activated inhibition to the deep nuclei. Sequential application of a gamma-aminobutyric acid type A receptor (GABA(A)R) agonist and a noncompetitive GABA(A)R antagonist allows selective blockade of stimulus-activated inhibition. By using the same sequential agonist and antagonist methods in behaving animals, we demonstrate that the conditioned response (CR) expression and timing are completely dissociable and involve different inhibitory inputs; although the basal inhibition modulates CR expression, the conditioned stimulus-activated inhibition is required for the proper timing of the CR. In addition, complete blockade of cerebellar deep nuclear GABA(A)Rs prevents CR acquisition. Together, these results suggest that different aspects of the memories for eyeblink CRs are encoded in the cerebellar cortex and the cerebellar deep nuclei.

  9. A novel urotensin II receptor antagonist, KR-36996, improved cardiac function and attenuated cardiac hypertrophy in experimental heart failure. (United States)

    Oh, Kwang-Seok; Lee, Jeong Hyun; Yi, Kyu Yang; Lim, Chae Jo; Park, Byung Kil; Seo, Ho Won; Lee, Byung Ho


    Urotensin II and its receptor are thought to be involved in various cardiovascular diseases such as heart failure, pulmonary hypertension and atherosclerosis. Since the regulation of the urotensin II/urotensin II receptor offers a great potential for therapeutic strategies related to the treatment of cardiovascular diseases, the study of selective and potent antagonists for urotensin II receptor is more fascinating. This study was designed to determine the potential therapeutic effects of a newly developed novel urotensin II receptor antagonist, N-(1-(3-bromo-4-(piperidin-4-yloxy)benzyl)piperidin-4-yl)benzo[b]thiophene-3-carboxamide (KR-36996), in experimental models of heart failure. KR-36996 displayed a high binding affinity (Ki=4.44±0.67nM) and selectivity for urotensin II receptor. In cell-based study, KR-36996 significantly inhibited urotensin II-induced stress fiber formation and cellular hypertrophy in H9c2UT cells. In transverse aortic constriction-induced cardiac hypertrophy model in mice, the daily oral administration of KR-36996 (30mg/kg) for 14 days significantly decreased left ventricular weight by 40% (Preceptor antagonist could efficiently attenuate both cardiac hypertrophy and dysfunction in experimental heart failure. KR-36996 may be useful as an effective urotensin II receptor antagonist for pharmaceutical or clinical applications.

  10. In vitro antagonistic growth effects of Lactobacillus fermentum and Lactobacillus salivarius and their fermentative broth on periodontal pathogens

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    Ling-Ju Chen


    Full Text Available As lactobacilli possess an antagonistic growth property, these bacteria may be beneficial as bioprotective agents for infection control. However, whether the antagonistic growth effects are attributed to the lactobacilli themselves or their fermentative broth remains unclear. The antagonistic growth effects of Lactobacillus salivarius and Lactobacillus fermentum as well as their fermentative broth were thus tested using both disc agar diffusion test and broth dilution method, and their effects on periodontal pathogens, including Streptococcus mutans, Streptococcus sanguis, and Porphyromonas gingivalisin vitro at different concentrations and for different time periods were also compared. Both Lactobacillus salivarius and Lactobacillus fermentum and their concentrated fermentative broth were shown to inhibit significantly the growth of Streptococcus mutans, Streptococcus sanguis, and Porphyromonas gingivalis, althoughdifferent inhibitory effects were observed for different pathogens. The higher the counts of lactobacilli and the higher the folds of concentrated fermentative broth, the stronger the inhibitory effects are observed. The inhibitory effect is demonstrated to be dose-dependent. Moreover, for the lactobacilli themselves, Lactobacillus fermentum showed stronger inhibitory effects than Lactobacillus salivarius. However, the fermentative broth of Lactobacillus fermentum showed weaker inhibitory effects than that of Lactobacillus salivarius. These data suggested that lactobacilli and their fermentative broth exhibit antagonistic growth activity, and consumption of probiotics or their broth containing lactobacilli may benefit oral health.

  11. Accelerated habit formation following amphetamine exposure is reversed by D1, but enhanced by D2, receptor antagonists

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    Andrew John Dudley Nelson


    Full Text Available Repeated exposure to the psychostimulant amphetamine has been shown to disrupt goal-directed instrumental actions and promote the early and abnormal development of goal-insensitive habitual responding (Nelson and Killcross, 2006. To investigate the neuropharmacological specificity of this effect as well as restore goal-directed responding in animals with pre-training amphetamine exposure, animals were treated with the non-selective dopamine antagonist α-flupenthixol, the selective D1 antagonist SCH 23390 or the selective D2 antagonist eticlopride, prior to instrumental training (3 sessions. Subsequently, the reinforcer was paired with LiCL-induced gastric-malaise and animals were given a test of goal-sensitivity both in extinction and reacquisition. The effect of these dopaminergic antagonists on the sensitivity of lever press performance to outcome devaluation was assessed in animals with pre-training exposure to amphetamine (Experiments 1a-1c or in non-sensitized animals (Experiment 2. Both α-flupenthixol and SCH23390 reversed accelerated habit formation following amphetamine sensitization. However, eticlopride appeared to enhance this effect and render instrumental performance compulsive as these animals were unable to inhibit responding both in extinction and reacquisition, even though a consumption test confirmed they had acquired an aversion to the reinforcer. These findings demonstrate that amphetamine induced-disruption of goal-directed behaviour is mediated by activity at distinct dopamine receptor subtypes and may represent a putative model of the neurochemical processes involved in the loss of voluntary control over behaviour.

  12. The Comparison of Antagonistic Effects of Normal Vaginal Lactobacilli and Some Commonly used Antibiotics on Isolated Bacteria of Uterine Infections in Dairy Cows

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    Pouya Dini


    Full Text Available Uterine infections are one of the major reproductive complications during postpartum. The antibiotics and antiseptic agents used in the treatment of postpartum infections have residues in food, induce bacterial resistance, increase the financial costs and cause failure in defense mechanism of host. On the other hand, nowadays the administration of probiotics is considered as an alternative method for the prevention and treatment of infections. Therefore, preventive treatment with probiotic product could decrease the usage of antibiotic and bring advantages in dairy farm systems. The objective of this study was screening of the antagonistic properties of isolated vaginal Lactic Acid Bacteria (LAB against the most prevalent bacteria in uterine infections in order to investigate their probiotic potentials as an alternative approach for prevention of uterine infections. LAB were isolated from sampling of cranial part of vagina during estrus phase and luteal phase of Holstein dairy cattle and pathogens bacteria were isolated from merits and endometritis specimens which referred to our veterinary laboratory. The antagonistic activity of isolated LAB against uterine pathogens was tested by Agar spot test. Antibiotic susceptibilities of pathogenic strains to commonly used antibiotics were investigated by using disc diffusion method. Inhibition zones around both the probiotic spots and the antibiotic discs were classified to weak, moderate and strong categories and their antagonistic efficacies were compared. Isolated LAB had antagonistic effects against all the pathogenic strains including both gram negative and gram positive, Arcanobacterium pyogenes and Pseudomonas aeroginosa were the most sensitive bacteria (with 12.60 and 14 mm an average inhibition zone, respectively. LAB had the least antagonistic effects on Clostridium perfringens (3.6 mm of an average inhibition zone. Comparing the antagonistic efficacies, the percentages of overall

  13. The pharmacological properties of lipophilic calcium antagonists. (United States)

    van Zwieten, P A


    Several types of calcium antagonists (CA) (verapamil, diltiazem, nifedipine and related drugs) may be used as antihypertensives. In practice, the dihydropyridines (nifedipine and related drugs) are the CA used most frequently as antihypertensives. Apart from the lowering of blood pressure CA may lead to other, theoretically beneficial, effects: regression of left ventricular and vascular hypertrophy, renal protection, weak natriuretic, weak antiplatelet, anti-ischaemic and antiatherogenic activity. Several new dihydropyridine CA have been introduced in recent years. The advantages of the newer compounds, such as amlodipine, felodipine, isradipine, lacidipine and lercanidipine, may include: vasoselectivity, hence little or no cardiodepressant activity; an improved kinetic profile, resulting in a slow onset and long duration of action, fewer side-effects such as reflex tachycardia and headache, owing to the slow onset of the antihypertensive action. For a few newer CA a predominant effect on specialized circulatory beds (renal, coronary and cerebral) has been claimed. The new CA, which are clearly lipophilic, deserve special attention. Owing to the lipophilic character of such compounds considerable concentration occurs in lipid-containing membrane depots. The CA thus concentrated are slowly released from these depots and, subsequently, reach their targets, the L-type calcium channels. This phenomenon explains both the slow onset and the long duration of action of these CA. Owing to the slow onset of action reflex tachycardia is virtually absent. The long duration of action allows satisfactory control of blood pressure in hypertensives by means of a single daily dose. A few lipophilic dihydropyridine CA are vasoselective. This property implies that at therapeutic, vasodilatory dosages no cardiodepressant activity occurs. Lercanidipine is a recently introduced example of a lipophilic and vasoselective dihydropyridine CA. It is an effective vasodilator

  14. Preclinical development of a novel class of CXCR4 antagonist impairing solid tumors growth and metastases.

    Directory of Open Access Journals (Sweden)

    Luigi Portella

    Full Text Available The CXCR4/CXCL12 axis plays a role in cancer metastases, stem cell mobilization and chemosensitization. Proof of concept for efficient CXCR4 inhibition has been demonstrated in stem cell mobilization prior to autologous transplantation in hematological malignancies. Nevertheless CXCR4 inhibitors suitable for prolonged use as required for anticancer therapy are not available. To develop new CXCR4 antagonists a rational, ligand-based approach was taken, distinct from the more commonly used development strategy. A three amino acid motif (Ar-Ar-X in CXCL12, also found in the reverse orientation (X-Ar-Ar in the vMIP-II inhibitory chemokine formed the core of nineteen cyclic peptides evaluated for inhibition of CXCR4-dependent migration, binding, P-ERK1/2-induction and calcium efflux. Peptides R, S and I were chosen for evaluation in in vivo models of lung metastases (B16-CXCR4 and KTM2 murine osteosarcoma cells and growth of a renal cells xenograft. Peptides R, S, and T significantly reduced the association of the 12G5-CXCR4 antibody to the receptor and inhibited CXCL12-induced calcium efflux. The four peptides efficiently inhibited CXCL12-dependent migration at concentrations as low as 10 nM and delayed CXCL12-mediated wound healing in PES43 human melanoma cells. Intraperitoneal treatment with peptides R, I or S drastically reduced the number of B16-CXCR4-derived lung metastases in C57/BL mice. KTM2 osteosarcoma lung metastases were also reduced in Balb/C mice following CXCR4 inhibition. All three peptides significantly inhibited subcutaneous growth of SN12C-EGFP renal cancer cells. A novel class of CXCR4 inhibitory peptides was discovered. Three peptides, R, I and S inhibited lung metastases and primary tumor growth and will be evaluated as anticancer agents.


    Directory of Open Access Journals (Sweden)

    B. B. Gegenava


    Full Text Available The role of aldosterone in pathophysiological processes is considered. The effects of the selective antagonist of mineralocorticoid receptor eplerenone are analyzed. The advantages of eplerenone compared with spironolactone are discussed.

  16. Secondary prevention with calcium antagonists after acute myocardial infarction

    DEFF Research Database (Denmark)

    Hansen, J F


    Experimental studies have demonstrated that the 3 calcium antagonists nifedipine, diltiazem, and verapamil have a comparable effect in the prevention of myocardial damage during ischaemia. Secondary prevention trials after acute myocardial infarction, which aimed at improving survival...

  17. Perampanel: A Selective AMPA Antagonist for Treating Seizures


    Krauss, Gregory L.


    Perampanel is a selective, noncompetitive AMPA receptor antagonist that has recently been approved for treating localization-related epilepsy. This article reviews the pharmacology, clinical development, efficacy, and safety/tolerability of perampanel.

  18. Complications of TNF-α antagonists and iron homeostasis (United States)

    TNF-α is a central regulator of inflammation and its blockade downregulates other proinflammatory cytokines, chemokines, and growth factors. Subsequently, TNF-α antagonists are currently used in treatment regimens directed toward several inflammatory diseases. Despite a beneficia...

  19. Effects of L-type Ca2+ channel antagonists on in vitro excystment of Paragonimus ohirai metacercariae induced by sodium cholate. (United States)

    Ikeda, Teruaki


    The inhibitory effects of L-type Ca2+ channel antagonists on Na cholate-induced in vitro excystment (CIIE) of Paragonimus ohirai metacercariae were studied. At concentrations of 10 microM, nicardipine and nimodipine inhibited CIIE completely and by approximately 92%, respectively. Nitrendipine and (+/-)-verapamil inhibited CIIE by about one half and one third, respectively. Nifedipine and diltiazem did not inhibit CIIE significantly. At higher concentrations, nitrendipine at 20 microM completely inhibited CIIE, and (+/-)-verapamil at 40 microM inhibited CIIE by 93%. Nifedipine and diltiazem inhibited CIIE only slightly and little, respectively, even at 40 microM. Complete inhibition by nicardipine at 10 microM required preincubation of metacercariae with the antagonist for 15 min. The inhibitory effects of nicardipine and nimodipine were reversible, and most of the nimodipine-treated metacercariae could excyst within 1 h after being washed, but the nicardipine-treated ones started to excyst 1 h after washing. Nicardipine suppressed the active movement of encysted juveniles evoked by Na cholate, whereas nimodipine did not suppress this significantly. These results suggested that L-type Ca2+ channels appeared to be involved in CIIE of P. ohirai metacercariae and that the inhibitory effect of the channels was due primarily to factors other than the inhibition of muscular activity, probably involving the secretion and release of enzymes lytic against the metacercarial cyst wall.

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

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen


    from such studies are currently accumulating and suggest that the histamine-2 receptor antagonists have potential beneficial effects in the treatment of certain malignant, autoimmune and skin diseases, either alone or in combination with other drugs. The beneficial effect of histamine-2 receptor...... antagonists as adjuvant single drugs to reduce trauma-, blood transfusion- and sepsis-induced immunosuppression has led to research in combined treatment regimens in major surgery, particularly, of patients operated on for malignant diseases....

  1. Structure-activity relationships of benzothiazole GPR35 antagonists. (United States)

    Abdalhameed, Manahil M; Zhao, Pingwei; Hurst, Dow P; Reggio, Patricia H; Abood, Mary E; Croatt, Mitchell P


    The first structure-activity relationships for a benzothiazole scaffold acting as an antagonist at GPR35 is presented. Analogues were designed based on a lead compound that was previously determined to have selective activity as a GPR35 antagonist. The synthetic route was modular in nature to independently explore the role of the middle and both ends of the scaffold. The activities of the analogues illustrate the importance of all three segments of the compound.

  2. Deficiency of interleukin-1 receptor antagonist responsive to anakinra. (United States)

    Schnellbacher, Charlotte; Ciocca, Giovanna; Menendez, Roxanna; Aksentijevich, Ivona; Goldbach-Mansky, Raphaela; Duarte, Ana M; Rivas-Chacon, Rafael


    We describe a 3-month-old infant who presented to our institution with interleukin (IL)-1 receptor antagonist deficiency (DIRA), which consists of neutrophilic pustular dermatosis, periostitis, aseptic multifocal osteomyelitis, and persistently high acute-phase reactants. Skin findings promptly improved upon initiation of treatment with anakinra (recombinant human IL-1 receptor antagonist), and the bony lesions and systemic inflammation resolved with continued therapy.

  3. Multiple Targeting Approaches on Histamine H3 Receptor Antagonists


    Mohammad eKhanfar; Anna eAffini; Kiril eLutsenko; Katarina eNikolic; Stefania eButini; Holger eStark


    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...

  4. Interleukin-2 receptor antagonists as induction therapy after heart transplantation

    DEFF Research Database (Denmark)

    Møller, Christian H; Gustafsson, Finn; Gluud, Christian;


    About half of the transplantation centers use induction therapy after heart transplantation. Interleukin-2 receptor antagonists (IL-2Ras) are used increasingly for induction therapy. We conducted a systematic review of randomized trials assessing IL-2Ras.......About half of the transplantation centers use induction therapy after heart transplantation. Interleukin-2 receptor antagonists (IL-2Ras) are used increasingly for induction therapy. We conducted a systematic review of randomized trials assessing IL-2Ras....

  5. Bone morphogenetic protein antagonist noggin promotes skin tumorigenesis via stimulation of the Wnt and Shh signaling pathways. (United States)

    Sharov, Andrey A; Mardaryev, Andrei N; Sharova, Tatyana Y; Grachtchouk, Marina; Atoyan, Ruzanna; Byers, H Randolph; Seykora, John T; Overbeek, Paul; Dlugosz, Andrzej; Botchkarev, Vladimir A


    Bone morphogenetic proteins (BMPs) play pivotal roles in the regulation of skin development. To study the role of BMPs in skin tumorigenesis, BMP antagonist noggin was used to generate keratin 14-targeted transgenic mice. In contrast to wild-type mice, transgenic mice developed spontaneous hair follicle-derived tumors, which resemble human trichofolliculoma. Global gene expression profiles revealed that in contrast to anagen hair follicles of wild-type mice, tumors of transgenic mice showed stage-dependent increases in the expression of genes encoding the selected components of Wnt and Shh pathways. Specifically, expression of the Wnt ligands increased at the initiation stage of tumor formation, whereas expression of the Wnt antagonist and tumor suppressor Wnt inhibitory factor-1 decreased, as compared with fully developed tumors. In contrast, expression of the components of Shh pathway increased in fully developed tumors, as compared with the tumor placodes. Consistent with the expression data, pharmacological treatment of transgenic mice with Wnt and Shh antagonists resulted in the stage-dependent inhibition of tumor initiation, and progression, respectively. Furthermore, BMP signaling stimulated Wnt inhibitory factor-1 expression and promoter activity in cultured tumor cells and HaCaT keratinocytes, as well as inhibited Shh expression, as compared with the corresponding controls. Thus, tumor suppressor activity of the BMPs in skin epithelium depends on the local concentrations of noggin and is mediated at least in part via stage-dependent antagonizing of Wnt and Shh signaling pathways.

  6. Dopamine antagonists and brief vision distinguish lens-induced- and form-deprivation-induced myopia. (United States)

    Nickla, Debora L; Totonelly, Kristen


    In eyes wearing negative lenses, the D2 dopamine antagonist spiperone was only partly effective in preventing the ameliorative effects of brief periods of vision (Nickla et al., 2010), in contrast to reports from studies using form-deprivation. The present study was done to directly compare the effects of spiperone, and the D1 antagonist SCH-23390, on the two different myopiagenic paradigms. 12-day old chickens wore monocular diffusers (form-deprivation) or -10 D lenses attached to the feathers with matching rings of Velcro. Each day for 4 days, 10 μl intravitreal injections of the dopamine D2/D4 antagonist spiperone (5 nmoles) or the D1 antagonist SCH-23390, were given under isoflurane anesthesia, and the diffusers (n = 16; n = 5, respectively) or lenses (n = 20; n = 6) were removed for 2 h immediately after. Saline injections prior to vision were done as controls (form-deprivation: n = 11; lenses: n = 10). Two other saline-injected groups wore the lenses (n = 12) or diffusers (n = 4) continuously. Axial dimensions were measured by high frequency A-scan ultrasonography at the start, and on the last day immediately prior to, and 3 h after the injection. Refractive errors were measured at the end of the experiment using a Hartinger's refractometer. In form-deprived eyes, spiperone, but not SCH-23390, prevented the ocular growth inhibition normally effected by the brief periods of vision (change in vitreous chamber depth, spiperone vs saline: 322 vs 211 μm; p = 0.01). By contrast, neither had any effect on negative lens-wearing eyes given similar unrestricted vision (210 and 234 μm respectively, vs 264 μm). The increased elongation in the spiperone-injected form-deprived eyes did not, however, result in a myopic shift, probably due to the inhibitory effect of the drug on anterior chamber growth (drug vs saline: 96 vs 160 μm; p < 0.01). Finally, spiperone inhibited the vision-induced transient choroidal thickening in form-deprived eyes, while SCH-23390 did not

  7. Intrathecal injection of glutamate receptor antagonists/agonist selectively attenuated rat pain-related behaviors induced by the venom of scorpion Buthus martensi Karsch. (United States)

    Liu, Tong; Pang, Xue-Yan; Bai, Zhan-Tao; Chai, Zhi-Fang; Jiang, Feng; Ji, Yong-Hua


    The present study investigated the involvement of spinal glutamate receptors in the induction and maintenance of the pain-related behaviors induced by the venom of scorpion Buthus martensi Karsch (BmK). (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5-10-imine hydrogen maleate (MK-801; 40nmol; a non-competitive NMDA receptor antagonist), 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 40nmol; a non-NMDA receptor antagonist), dl-amino-3-phosphonopropionic acid (dl-AP3; 100nmol; a group I metabotropic glutamate receptor antagonist) and 4-aminopyrrolidine-2,4-dicarboxylate (APDC; 100nmol; a group II metabotropic glutamate receptor agonist) were employed. On intrathecal injection of glutamate receptor antagonists/agonist before BmK venom administration by 10min, BmK venom-induced spontaneous nociceptive responses could be suppressed by all tested agents. Primary thermal hyperalgesia could be inhibited by MK-801 and dl-AP3, while bilateral mechanical hyperalgesia could be inhibited by CNQX and dl-AP3 and contralateral mechanical hyperalgesia could be inhibited by APDC. On intrathecal injection of glutamate receptor antagonists/agonist after BmK venom injection by 4.5h, primary thermal hyperalgesia could be partially reversed by all tested agents, while bilateral mechanical hyperalgesia could only be inhibited by APDC. The results suggest that the role of spinal glutamate receptors may be different on the various manifestations of BmK venom-induced pain-related behaviors.

  8. Antagonistic crosstalk between NF-κB and SIRT1 in the regulation of inflammation and metabolic disorders. (United States)

    Kauppinen, Anu; Suuronen, Tiina; Ojala, Johanna; Kaarniranta, Kai; Salminen, Antero


    Recent studies have indicated that the regulation of innate immunity and energy metabolism are connected together through an antagonistic crosstalk between NF-κB and SIRT1 signaling pathways. NF-κB signaling has a major role in innate immunity defense while SIRT1 regulates the oxidative respiration and cellular survival. However, NF-κB signaling can stimulate glycolytic energy flux during acute inflammation, whereas SIRT1 activation inhibits NF-κB signaling and enhances oxidative metabolism and the resolution of inflammation. SIRT1 inhibits NF-κB signaling directly by deacetylating the p65 subunit of NF-κB complex. SIRT1 stimulates oxidative energy production via the activation of AMPK, PPARα and PGC-1α and simultaneously, these factors inhibit NF-κB signaling and suppress inflammation. On the other hand, NF-κB signaling down-regulates SIRT1 activity through the expression of miR-34a, IFNγ, and reactive oxygen species. The inhibition of SIRT1 disrupts oxidative energy metabolism and stimulates the NF-κB-induced inflammatory responses present in many chronic metabolic and age-related diseases. We will examine the molecular mechanisms of the antagonistic signaling between NF-κB and SIRT1 and describe how this crosstalk controls inflammatory process and energy metabolism. In addition, we will discuss how disturbances in this signaling crosstalk induce the appearance of chronic inflammation in metabolic diseases.

  9. Structure of neuroblastoma suppressor of tumorigenicity 1 (NBL1): insights for the functional variability across bone morphogenetic protein (BMP) antagonists. (United States)

    Nolan, Kristof; Kattamuri, Chandramohan; Luedeke, David M; Angerman, Elizabeth B; Rankin, Scott A; Stevens, Mariana L; Zorn, Aaron M; Thompson, Thomas B


    Bone morphogenetic proteins (BMPs) are antagonized through the action of numerous extracellular protein antagonists, including members from the differential screening-selected gene aberrative in neuroblastoma (DAN) family. In vivo, misregulation of the balance between BMP signaling and DAN inhibition can lead to numerous disease states, including cancer, kidney nephropathy, and pulmonary arterial hypertension. Despite this importance, very little information is available describing how DAN family proteins effectively inhibit BMP ligands. Furthermore, our understanding for how differences in individual DAN family members arise, including affinity and specificity, remains underdeveloped. Here, we present the structure of the founding member of the DAN family, neuroblastoma suppressor of tumorigenicity 1 (NBL1). Comparing NBL1 to the structure of protein related to Dan and Cerberus (PRDC), a more potent BMP antagonist within the DAN family, a number of differences were identified. Through a mutagenesis-based approach, we were able to correlate the BMP binding epitope in NBL1 with that in PRDC, where introduction of specific PRDC amino acids in NBL1 (A58F and S67Y) correlated with a gain-of-function inhibition toward BMP2 and BMP7, but not GDF5. Although NBL1(S67Y) was able to antagonize BMP7 as effectively as PRDC, NBL1(S67Y) was still 32-fold weaker than PRDC against BMP2. Taken together, this data suggests that alterations in the BMP binding epitope can partially account for differences in the potency of BMP inhibition within the DAN family.

  10. Effects of α-adrenoreceptor antagonists on apoptosis and proliferation of pancreatic cancer cells in vitro

    Institute of Scientific and Technical Information of China (English)

    Su-Gang Shen; Dong Zhang; Heng-Tong Hu; Jun-Hui Li; Zheng Wang; Qing-Yong Ma


    AIM: To discuss the expression of α-adrenoreceptors in pancreatic cancer cell lines PC-2 and PC-3 and the effects of α1- and α2-adrenoreceptor antagonists, yohimbine and urapidil hydrochloride, on the cell lines in vitro.METHODS: We cultured the human ductal pancreatic adenocarcinoma cell lines PC-2 and PC-3 and analyzed the mRNA expression of α1- and α2-adrenergic receptors by reverse transcription polymerase chain reaction (RT-PCR).The effects of yohimbine and urapidil hydrochloride on cell proliferation were assessed by 3-(4,5-dimethylthiasol-2-yl)2,4,-diphenyltetrazolium bromide (MTT) assay. Apoptosis was detected using the terminal deoxyribonucleoticlyl transferase (TdT)-mediated biotin-16-dUTP nick-end labeling (TUNEL) assay and flow cytometry (FCM).RESULTS: PC-2 expressed rnRNA in α1- and α2-adrenoreceptors. MTT assays showed that urapidil hydrochloride had no effect on PC-3 cell lines. However,exposure to urapidil hydrochloride increased DNA synthesis in PC-2 cell lines as compared to the control group. PC-2 cell lines were sensitive to both drugs. The proliferation of the 2 cell lines was inhibited by yohimbine.Cell proliferation was inhibited by yohimbine via apoptosis induction.CONCLUSION: The expression of α1-and α2-adrenoreceptors is different in PC-2 and PC-3 cell lines,which might be indicative of their different functions. Theα2-adrenoceptor antagonist, yohimbine, can inhibit the proliferation of both cell lines and induce their apoptosis,suggesting that yohimbine can be used as an anticancer drug for apoptosis of PC-2 and PC-3 cells.

  11. Dietary component isorhamnetin is a PPARγ antagonist and ameliorates metabolic disorders induced by diet or leptin deficiency. (United States)

    Zhang, Yu; Gu, Ming; Cai, Wujie; Yu, Lijing; Feng, Li; Zhang, Lu; Zang, Qingqing; Wang, Yahui; Wang, Dongshan; Chen, Hui; Tong, Qingchun; Ji, Guang; Huang, Cheng


    Studies on peroxisome proliferator-activated receptor (PPAR)-γ ligands have been focused on agonists. However, PPARγ activation may induce obesity and nonalcoholic fatty liver disease (NAFLD), one of the most challenging medical conditions. Here, we identified that isorhamnetin, a naturally occurring compound in fruits and vegetables and the metabolite of quercetin, is a novel antagonist of PPARγ. Isorhamnetin treatment inhibited the adipocyte differentiation induced by the PPARγ agonist rosiglitazone, reduced obesity development and ameliorated hepatic steatosis induced by both high-fat diet treatment and leptin deficiency. Our results suggest that dietary supplement of isorhamnetin may be beneficial to prevent obesity and steatosis and PPARγ antagonists may be useful to treat hepatic steatosis.

  12. Medicinal chemistry of small molecule CCR5 antagonists for blocking HIV-1 entry: a review of structural evolution. (United States)

    Tian, Ye; Zhang, Dujuan; Zhan, Peng; Liu, Xinyong


    CCR5, a member of G protein-coupled receptors superfamily, plays an important role in the HIV-1 entry process. Antagonism of this receptor finally leads to the inhibition of R5 strains of HIV entry into the human cells. The identification of CCR5 antagonists as antiviral agents will provide more option for HAART. Now, more than a decade after the first small molecule CCR5 inhibitor was discovered, great achievements have been made. In this article, we will give a brief introduction of several series of small molecule CCR5 antagonists, focused on their appealing structure evolution, essential SAR information and thereof the enlightenment of strategies on CCR5 inhibitors design.

  13. Design and Synthesis of a Series of Pyrido[2,3-d]pyrimidine Derivatives as CCR4 Antagonists

    Directory of Open Access Journals (Sweden)

    Ying Wang


    Full Text Available A series of pyrido[2,3-d]pyrimidine derivatives were designed and synthesized based on known CC chemokine receptor 4 (CCR4 antagonists. The activities of all the newly synthesized compounds were evaluated using a chemotaxis inhibition assay. Compound 6b was proven to be a potent CCR4 antagonist that can block cell chemotaxis induced by macrophage-derived chemokine (MDC, thymus and activation regulated chemokine (TARC, and CKLF1, the natural ligands of CCR4. In addition, compound 6b is more effective than budesonide in the murine rhinitis model. The intravenous injection LD50 of compound 6b is 175 mg/kg and the oral LD50 is greater than 2,000 mg/kg.

  14. Identification of putative steroid receptor antagonists in bottled water: combining bioassays and high-resolution mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Martin Wagner

    Full Text Available Endocrine disrupting chemicals (EDCs are man-made compounds interfering with hormone signaling and thereby adversely affecting human health. Recent reports provide evidence for the presence of EDCs in commercially available bottled water, including steroid receptor agonists and antagonists. However, since these findings are based on biological data the causative chemicals remain unidentified and, therefore, inaccessible for toxicological evaluation. Thus, the aim of this study is to assess the antiestrogenic and antiandrogenic activity of bottled water and to identify the causative steroid receptor antagonists. We evaluated the antiestrogenic and antiandrogenic activity of 18 bottled water products in reporter gene assays for human estrogen receptor alpha and androgen receptor. Using nontarget high-resolution mass spectrometry (LTQ-Orbitrap Velos, we acquired corresponding analytical data. We combined the biological and chemical information to determine the exact mass of the tentative steroid receptor antagonist. Further MS(n experiments elucidated the molecule's structure and enabled its identification. We detected significant antiestrogenicity in 13 of 18 products. 16 samples were antiandrogenic inhibiting the androgen receptor by up to 90%. Nontarget chemical analysis revealed that out of 24520 candidates present in bottled water one was consistently correlated with the antagonistic activity. By combining experimental and in silico MS(n data we identified this compound as di(2-ethylhexyl fumarate (DEHF. We confirmed the identity and biological activity of DEHF and additional isomers of dioctyl fumarate and maleate using authentic standards. Since DEHF is antiestrogenic but not antiandrogenic we conclude that additional, yet unidentified EDCs must contribute to the antagonistic effect of bottled water. Applying a novel approach to combine biological and chemical analysis this is the first study to identify so far unknown EDCs in bottled water

  15. Identification of Putative Steroid Receptor Antagonists in Bottled Water: Combining Bioassays and High-Resolution Mass Spectrometry (United States)

    Wagner, Martin; Schlüsener, Michael P.; Ternes, Thomas A.; Oehlmann, Jörg


    Endocrine disrupting chemicals (EDCs) are man-made compounds interfering with hormone signaling and thereby adversely affecting human health. Recent reports provide evidence for the presence of EDCs in commercially available bottled water, including steroid receptor agonists and antagonists. However, since these findings are based on biological data the causative chemicals remain unidentified and, therefore, inaccessible for toxicological evaluation. Thus, the aim of this study is to assess the antiestrogenic and antiandrogenic activity of bottled water and to identify the causative steroid receptor antagonists. We evaluated the antiestrogenic and antiandrogenic activity of 18 bottled water products in reporter gene assays for human estrogen receptor alpha and androgen receptor. Using nontarget high-resolution mass spectrometry (LTQ-Orbitrap Velos), we acquired corresponding analytical data. We combined the biological and chemical information to determine the exact mass of the tentative steroid receptor antagonist. Further MSn experiments elucidated the molecule’s structure and enabled its identification. We detected significant antiestrogenicity in 13 of 18 products. 16 samples were antiandrogenic inhibiting the androgen receptor by up to 90%. Nontarget chemical analysis revealed that out of 24520 candidates present in bottled water one was consistently correlated with the antagonistic activity. By combining experimental and in silico MSn data we identified this compound as di(2-ethylhexyl) fumarate (DEHF). We confirmed the identity and biological activity of DEHF and additional isomers of dioctyl fumarate and maleate using authentic standards. Since DEHF is antiestrogenic but not antiandrogenic we conclude that additional, yet unidentified EDCs must contribute to the antagonistic effect of bottled water. Applying a novel approach to combine biological and chemical analysis this is the first study to identify so far unknown EDCs in bottled water. Notably

  16. Discovery of aryl ureas and aryl amides as potent and selective histamine H3 receptor antagonists for the treatment of obesity (part II). (United States)

    Gao, Zhongli; Hurst, William J; Guillot, Etienne; Czechtizky, Werngard; Lukasczyk, Ulrike; Nagorny, Raisa; Pruniaux, Marie-Pierre; Schwink, Lothar; Sanchez, Juan Antonio; Stengelin, Siegfried; Tang, Lei; Winkler, Irvin; Hendrix, James A; George, Pascal G


    A novel series of histamine H3 receptor (H3R) antagonists was derived from an arylurea lead series (1) via bioisosteric replacement of the urea functionality by an amide linkage. The arylamide series was optimized through SAR studies by a broad variation of substituents in the left-hand side benzoyl residue (analogs 2a-2ag) or replacement of the benzoyl moiety by heteroarylcarbonyl residues (analogs 5a-5n). Compounds 2p and 2q were identified within the series as potent and selective H3R antagonists/inverse agonists with acceptable overall profile. Compound 2q was orally active in food intake inhibition in diet-induced obese (DIO) mice. Compound 2q represents a novel H3R antagonist template with improved in vitro potency and oral efficacy and has its merits as a new lead for further optimization.

  17. Acute inhibition of corticosteroidogenesis by inhibitors of calmodulin action. (United States)

    Carsia, R V; Moyle, W R; Wolff, D J; Malamed, S


    To identify the possible role of calmodulin in ACTH function, we tested the ability of chlorpromazine (CP) and other calmodulin antagonists to inhibit steroidogenesis of isolated adrenocortical cells of the rat. CP reversibly inhibited maximal ACTH-induced corticosterone (B) production. The presence of the drug did not alter the ED50 of ACTH stimulation (3.2 X 10(3) pg/ml), suggesting that it inhibited ACTH-induced steroidogenesis in a noncompetitive manner. The CP concentration required for half-maximal inhibition was 8.2 microM, a value close to the dissociation constant of the CP-calmodulin complex (5.3 microM). Concentrations greater than 40 microM resulted in complete inhibition. Similar concentrations of CP inhibited ACTH-induced cAMP accumulation in a dose-dependent manner, indicating an effect of the drug on early events in ACTH action. In addition, CP also apparently acted at a site distal to the point of cAMP formation, as shown by the finding that it inhibited cAMP-induced B production. CP inhibition of ACTH-induced B production was independent of the Ca2+ concentration, suggesting that the drug did not compete with Ca2+ directly. Concentrations of CP greater than 20 microM inhibited protein synthesis as measured by leucine incorporation into cellular proteins. Thus, although the inhibitory effect of high concentrations of CP on steroidogenesis might be explained by an effect on protein synthesis, the inhibition seen at 10 microM appeared to be independent of protein synthesis. Other antagonists of calmodulin action inhibited maximal ACTH-induced B production with the following relative potencies: trifluoperazine greater than CP greater than haloperidol greater than chlordiazepoxide. This order is similar to that reported for inhibition of calmodulin-activated phosphodiesterase and for binding to calmodulin. These findings suggest that calmodulin may modulate the effect of ACTH on steroidogenesis at multiple sites.

  18. Antagonist properties of Conus parius peptides on N-methyl-D-aspartate receptors and their effects on CREB signaling.

    Directory of Open Access Journals (Sweden)

    Shailaja Kunda

    Full Text Available Three members of a family of small neurotoxic peptides from the venom of Conus parius, conantokins (Con Pr1, Pr2, and Pr3, function as antagonists of N-methyl-D-aspartate receptors (NMDAR. We report structural characterizations of these synthetic peptides, and also demonstrate their antagonistic properties toward ion flow through NMDAR ion channels in primary neurons. ConPr1 and ConPr2 displayed moderate increases in α-helicity after addition of Mg(2+. Native apo-ConPr3 possessed an α-helical conformation, and the helicity increased only slightly on addition of Mg(2+. Additionally, these peptides diminished NMDA/Gly-mediated currents and intracellular Ca(2+ (iCa(2+ influx in mature rat primary hippocampal neurons. Electrophysiological data showed that these peptides displayed slower antagonistic properties toward the NMDAR than conantokins from other species of cone snails, e.g., ConT and ConG. Furthermore, to demonstrate selectivity of the C. parius-derived conantokins towards specific NMDAR subunits, cortical neurons from GluN2A(-/- and GluN2B(-/- mice were utilized. Robust inhibition of NMDAR-mediated stimulation in GluN2A(-/--derived mouse neurons, as compared to those isolated from GluN2B(-/--mouse brains, was observed, suggesting a greater selectivity of these antagonists towards the GluN2B subunit. These C. parius conantokins mildly inhibited NMDAR-induced phosphorylation of CREB at Ser(133, suggesting that the peptides modulated iCa(2+ entry and, thereby, activation of CREB, a transcription factor that is required for maintaining long-term synaptic activity. Our data mechanistically show that while these peptides effectively antagonize NMDAR-directed current and iCa(2+ influx, receptor-coupled CREB signaling is maintained. The consequence of sustained CREB signaling is improved neuronal plasticity and survival during neuropathologies.

  19. Antagonist properties of Conus parius peptides on N-methyl-D-aspartate receptors and their effects on CREB signaling. (United States)

    Kunda, Shailaja; Cheriyan, John; Hur, Michael; Balsara, Rashna D; Castellino, Francis J


    Three members of a family of small neurotoxic peptides from the venom of Conus parius, conantokins (Con) Pr1, Pr2, and Pr3, function as antagonists of N-methyl-D-aspartate receptors (NMDAR). We report structural characterizations of these synthetic peptides, and also demonstrate their antagonistic properties toward ion flow through NMDAR ion channels in primary neurons. ConPr1 and ConPr2 displayed moderate increases in α-helicity after addition of Mg(2+). Native apo-ConPr3 possessed an α-helical conformation, and the helicity increased only slightly on addition of Mg(2+). Additionally, these peptides diminished NMDA/Gly-mediated currents and intracellular Ca(2+) (iCa(2+)) influx in mature rat primary hippocampal neurons. Electrophysiological data showed that these peptides displayed slower antagonistic properties toward the NMDAR than conantokins from other species of cone snails, e.g., ConT and ConG. Furthermore, to demonstrate selectivity of the C. parius-derived conantokins towards specific NMDAR subunits, cortical neurons from GluN2A(-/-) and GluN2B(-/-) mice were utilized. Robust inhibition of NMDAR-mediated stimulation in GluN2A(-/-)-derived mouse neurons, as compared to those isolated from GluN2B(-/-)-mouse brains, was observed, suggesting a greater selectivity of these antagonists towards the GluN2B subunit. These C. parius conantokins mildly inhibited NMDAR-induced phosphorylation of CREB at Ser(133), suggesting that the peptides modulated iCa(2+) entry and, thereby, activation of CREB, a transcription factor that is required for maintaining long-term synaptic activity. Our data mechanistically show that while these peptides effectively antagonize NMDAR-directed current and iCa(2+) influx, receptor-coupled CREB signaling is maintained. The consequence of sustained CREB signaling is improved neuronal plasticity and survival during neuropathologies.

  20. Neuroprotective and memory-related actions of novel alpha-7 nicotinic agents with different mixed agonist/antagonist properties. (United States)

    Meyer, E M; Tay, E T; Zoltewicz, J A; Meyers, C; King, M A; Papke, R L; De Fiebre, C M


    The goals of this study were to develop compounds that were selective and highly efficacious agonists at alpha-7 receptors, while varying in antagonist activity; and to test the hypothesis that these compounds had memory-related and neuroprotective actions associated with both agonist and antagonist alpha-7 receptor activities. Three compounds were identified; E,E-3-(cinnamylidene)anabaseine (3-CA), E,E-3-(2-methoxycinnamylidene) anabaseine (2-MeOCA) and E,E-3-(4-methoxycinnamylidene) anabaseine (4-MeOCA) each displaced [125I]alpha-bungarotoxin binding from rat brain membranes and activated rat alpha-7 receptors in a Xenopus oocyte expression system fully efficaciously. The potency series for binding and receptor activation was 2-MeOCA > 4-MeOCA = 3-CA and 2-MeOCA = 3-CA > 4-MeOCA, respectively. No compound significantly activated oocyte-expressed alpha-4beta-2 receptors. Although each cinnamylidene-anabaseine caused a long-term inhibition of alpha-7 receptors, as measured by ACh-application 5 min later, this inhibition ranged considerably, from less than 20% (3-CA) to 90% (2-MeOCA) at an identical concentration (10 microM). These compounds improved passive avoidance behavior in nucleus basalis lesioned rats, with 2-MeOCA most potent in this respect. In contrast, only 3-CA was neuroprotective against neurite loss during nerve growth factor deprivation in differentiated rat pheochromocytoma (PC12) cells. Choline, an efficacious alpha-7 agonist without antagonist activity, was also protective in this model. These results suggest that the neurite-protective action of alpha-7 receptor agonists may be more sensitive to potential long-term antagonist properties than acute behavioral actions are.

  1. CRF receptor antagonist astressin-B reverses and prevents alopecia in CRF over-expressing mice.

    Directory of Open Access Journals (Sweden)

    Lixin Wang

    Full Text Available Corticotropin-releasing factor (CRF signaling pathways are involved in the stress response, and there is growing evidence supporting hair growth inhibition of murine hair follicle in vivo upon stress exposure. We investigated whether the blockade of CRF receptors influences the development of hair loss in CRF over-expressing (OE-mice that display phenotypes of Cushing's syndrome and chronic stress, including alopecia. The non-selective CRF receptors antagonist, astressin-B (5 µg/mouse injected peripherally once a day for 5 days in 4-9 months old CRF-OE alopecic mice induced pigmentation and hair re-growth that was largely retained for over 4 months. In young CRF-OE mice, astressin-B prevented the development of alopecia that occurred in saline-treated mice. Histological examination indicated that alopecic CRF-OE mice had hair follicle atrophy and that astressin-B revived the hair follicle from the telogen to anagen phase. However, astressin-B did not show any effect on the elevated plasma corticosterone levels and the increased weights of adrenal glands and visceral fat in CRF-OE mice. The selective CRF₂ receptor antagonist, astressin₂-B had moderate effect on pigmentation, but not on hair re-growth. The commercial drug for alopecia, minoxidil only showed partial effect on hair re-growth. These data support the existence of a key molecular switching mechanism triggered by blocking peripheral CRF receptors with an antagonist to reset hair growth in a mouse model of alopecia associated with chronic stress.

  2. Antagonistic effect of Pseudomonas aeruginosa isolates from various ecological niches on Vibrio species pathogenic to crustaceans

    Institute of Scientific and Technical Information of China (English)

    Prabhakaran Priyaja; Puthumana Jayesh; Neil Scolastin Correya; Balachandran Sreelakshmi; Naduthalmuriparambil S Sudheer; Rosamma Philip; Isaac Sarogeni Bright Singh


    Objective: To abrogate pathogenic vibrios in aquaculture by testing the potential of Pseudomonas isolates from fresh water, brackish and marine environments as probiotics.Methods:Antagonistic activity of the compound against 7 Vibrio spp. was performed. Influence of salinity on the production of pyocyanin and the toxicity was done through the compound using brine shrimp lethality assay. Molecular characterization was performed to confirm that the isolates werePseudomonas aeruginosa. Results: Salinity was found to regulate the levels of pyocyanin production, with 5-10 g/L as the optimum. All Pseudomonas isolates grew at salinities ranging from 5 to 70 g/L. Isolates of marine origin produced detectable levels of pyocyanin up to 45 g/L salinity. Brackish and freshwater isolates ceased to produce pyocyanin at salinities above 30 g/L and 20 g/L, respectively. Culture supernatants of all 5 Pseudomonas isolates possessed the ability to restrict the growth of Vibrio spp. and maximum antagonistic effect on Vibrio harveyi was obtained when they were grown at salinities of 5 to 10 g/L. The marine isolate MCCB117, even when grown at a salinity of 45 g/L possessed the ability to inhibit Vibrio spp.Conclusions:Purification and structural elucidation of antagonistic compound were carried out. ideal for application in freshwater, MCCB102 and MCCB103 in brackish water and MCCB117 and The present investigation showed that Pseudomonas aeruginosa MCCB119 would be MCCB118 in marine aquaculture systems as putative probiotics in the management of vibrios.

  3. Inhibition of glioblastoma cell proliferation, migration and invasion by the proteasome antagonist carfilzomib. (United States)

    Areeb, Zammam; Stylli, Stanley S; Ware, Thomas M B; Harris, Nicole C; Shukla, Lipi; Shayan, Ramin; Paradiso, Lucia; Li, Bo; Morokoff, Andrew P; Kaye, Andrew H; Luwor, Rodney B


    Glioblastoma multiforme is the most aggressive and lethal tumor of the central nervous system with limited treatment strategies on offer, and as such the identification of effective novel therapeutic agents is paramount. To examine the efficacy of proteasome inhibitors, we tested bortezomib, carfilzomib, nafamostat mesylate, gabexate mesylate and acetylsalicylic acid on glioblastoma cell viability, migration and invasion. Both bortezomib and carfilzomib produced significant reduction of cell viability, while nafamostat mesylate, gabexate mesylate and acetylsalicylic acid did not. Subsequent testing showed that carfilzomib significantly reduced cell viability at nM concentrations. Carfilzomib also reduced cell migration, secretion and activation of MMP2 and also cell invasion of all four glioblastoma cells tested. In summary, carfilzomib represents a novel, yet FDA-approved agent for the treatment of glioblastoma multiforme.

  4. Increased central facilitation of antagonist reciprocal inhibition at the onset of dorsiflexion following explosive strength training

    DEFF Research Database (Denmark)

    Geertsen, Svend Sparre; Jensen, Jesper Lundbye; Nielsen, Jens Bo


    was measured as the depression of the soleus H reflex following conditioning stimulation of the peroneal nerve (1.1 x motor threshold) at an interval of 2-3 ms. At the onset of dorsiflexion the amount of DRI measured relative to DRI at rest increased significantly from 6% before the training to 22% after...

  5. Novel CXCR3/CXCR7-Directed Biological Antagonist for Inhibition of Breast Cancer Progression (United States)


    the role of CXCR4 in BrCa progression. 4 Figure 2. CXCR7 (G protein-independent) cell-signaling pathways. The GPCR , CXCR7 is hypothesized to... antibody responses. Aim Two will characterize the mechanisms of mut-CXCL11-Ig that modulate BrCa progression in the presence and absence of docetaxel...and iv) Micromet. Imagestream analysis of protein expression and localization: PE/Cy5 conjugated anti-human CXCR4 antibody (clone#12G5) was purchased

  6. Novel CXCR3/CXCR7-Directed Biological Antagonist for Inhibition of Breast Cancer Progression (United States)


    purchased from Biolegend, Inc. Polyclonal rabbit anti-CXCR7 antibody was purchased from GeneTex, Inc and conjugated with a donkey -anti-rabbit-FITC antibody... donkey -anti-rabbit-FITC and PE/Cy5 anti-human CXCR4 antibody. After staining, cells were washed with FACS buffer and analyzed. 7-AAD was used to...MCF-7 and MDA-MB-231 cell lines were stained with polyclonal-rabbit anti-CXCR7 antibody conjugated with donkey -anti-rabbit-FITC and PE/Cy5 anti

  7. Penicillium expansum versus antagonist yeasts and patulin degradation in vitro

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    Alexandre Rodrigo Coelho


    Full Text Available Taking into account the preliminary antagonistic/biodegradation property showed by Pichia membranifaciens and Sporobolomyces roseus, which decreased the initial patulin concentration of 588.4 to 290.0 µg/mL, ability of P. ohmeri 158 in biocontrol against Penicillium expansum and patulin decrease in vitro was performed. The culture supernatant of P. ohmeri 158 was effective against 66.17% micelial growth, indicating antibiosis related with the killer phenomenon. The initial patulin concentration of 223 µg in the presence of P. ohmeri 158 cells was decreased over 83% of the original concentration, when incubated at 25ºC/2 days and > 99% after 5 days incubation time, with undetectable patulin level after 15 days. The initial pH 4.0 decreased to pH 3.3 along 15 days experiment, suggesting that patulin decrease was an active process and a consequence of yeast metabolism. The results suggested that P. ohmeri 158 could be a promising alternative for the inhibition of P. expansum growth and patulin degradation.Considerando o antagonismo e degradação de patulina detectados em Pichia membranifaciens e Sporobolomyces roseus no estudo preliminar, este trabalho avaliou o efeito antagônico de Pichia ohmeri 158 no desenvolvimento de Penicillium expansum e a degradação de patulina "in vitro". O sobrenadante do cultivo de P. ohmeri 158 inibiu 66,17% do desenvolvimento micelial, indicando antibiose relacionada ao fator killer. A concentração inicial de patulina (223 µg na presença de células íntegras de P. ohmeri foi reduzida em mais de 83% após dois dias de incubação a 25ºC e superior a 99% após 5 dias, com níveis indetectáveis no 15º dia. O decréscimo do pH 4,0 inicial para pH 3,3 sugeriu que a eliminação de patulina é um processo ativo e uma conseqüência do metabolismo da levedura. Os resultados obtidos concluem que P. ohmeri 158 é uma alternativa promissora na inibição do desenvolvimento de P. expansum e na degradação de

  8. Identification of atropine- and P2X1 receptor antagonist-resistant, neurogenic contractions of the urinary bladder. (United States)

    Kennedy, Charles; Tasker, Paul N; Gallacher, Gemma; Westfall, Timothy D


    Acetylcholine and ATP are excitatory cotransmitters in parasympathetic nerves. We used P2X1 receptor antagonists to further characterize the purinergic component of neurotransmission in isolated detrusor muscle of guinea pig urinary bladder. In the presence of atropine (1 microM) and prazosin (100 nM), pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) (0.1-100 microM) and suramin (1-300 microM) inhibited contractions evoked by 4 Hz nerve stimulation in a concentration-dependent manner (IC50 of 6.9 and 13.4 microM, respectively). Maximum inhibition was 50-60%, which was unaffected by coadministration of the ectonucleotidase inhibitor ARL67156 (6-N,N-diethyl-D-beta,gamma-dibromomethyleneATP) (100 microM). The remaining responses were abolished by tetrodotoxin (1 microM). PPADS and suramin also reduced contractions to exogenous ATP (300 microM) by 40-50%, but abolished those to the P2X1 agonist alpha,beta-methyleneATP (alpha,beta-meATP) (1 microM). The P2X1 antagonists reactive blue 2, NF279 (8,8'-[carbonylbis(imino-4,1-phenylenecarbonylimino-4,1-phenylenecarbonylimino)] bis-1,3,5-naphthalenetrisulfonic acid), MRS2159 (pyridoxal-alpha5-phosphate-6-phenylazo-4'-carboxylic acid) (100 microM), and NF449 [4,4',4,4-(carbonylbis(imino-5,1,3-benzenetriylbis(carbonylimino)))tetrakis-benzene-1,3-disulfonic acid] (3 microM) abolished contractions to alpha,beta-meATP (1 microM; n = 4-5), but only reduced contractions evoked by 4 Hz nerve stimulation by approximately 40-60% (n = 4-6) and ATP by 30-60% (n = 4-7). However, prolonged exposure to alpha,beta-meATP (50 microM) abolished contractions evoked by all three stimuli (n = 5-12). PPADS (100 microM) and suramin (300 microM) reduced the peak neurogenic contraction of the mouse urinary bladder to 30-40% of control. At the same concentrations, the P2X1 antagonists abolished the nonadrenergic, purinergic component of neurogenic contractions in the guinea pig vas deferens (n = 4-5). Thus, P2X1 receptor antagonists inhibit

  9. A pharmacophore model for dopamine D4 receptor antagonists (United States)

    Boström, Jonas; Gundertofte, Klaus; Liljefors, Tommy


    A pharmacophore model for dopamine D4 antagonists has been developed on the basis of a previously reported dopamine D2 model. By using exhaustive conformational analyses (MM3* force field and the GB/SA hydration model) and least-squares molecular superimposition studies, a set of eighteen structurally diverse high affinity D4 antagonists have successfully been accommodated in the D4 pharmacophore model. Enantioselectivities may be rationalized by conformational energies required for the enantiomers to adopt their proposed bioactive conformations. The pharmacophore models for antagonists at the D4 and D2 receptor subtypes have been compared in order to get insight into molecular properties of importance for D2/D4 receptor selectivity. It is concluded that the bioactive conformations of antagonists at the two receptor subtypes are essentially identical. Receptor essential volumes previously identified for the D2 receptor are shown to be present also in the D4 receptor. In addition, a novel receptor essential volume in the D4 receptor, not present in the D2 receptor, has been identified. This feature may be exploited for the design of D4 selective antagonists. However, it is concluded that the major determinant for D2/D4 selectivity is the nature of the interactions between the receptor and aromatic ring systems. The effects of the electronic properties of these ring systems on the affinities for the two receptor subtypes differ substantially.

  10. A novel BLyS antagonist peptide designed based on the 3-D complex structure of BCMA and BLyS. (United States)

    Sun, Jian; Feng, Jiannan; Li, Yan; Shen, Beifen


    B lymphocyte stimulator (BLyS) is a member of tumor necrosis factor (TNF) family. Because of its roles in autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and Sjogren syndrome (SS), BLyS antagonists have been tested to treat SLE- and RA-like symptoms in mice and obtained optimistic results. So far, reported BLyS antagonists were mostly decoyed BLyS receptors or anti-BLyS antibodies. In this study, a novel BLyS antagonist peptide, PT, was designed based on the modeling 3-D complex structure of BCMA and BLyS. The interaction mode of PT with BLyS was analyzed theoretically. The results of competitive ELISA demonstrated that PT could inhibit the binding of BCMA-Fc and anti-BLyS antibody to BLyS in vitro. In addition, PT could partly block the proliferating activity of BLyS on mice splenocytes. The BLyS antagonizing activity of PT was significant (p<0.05). This study highlights the possibility of using BLyS antagonist peptide to neutralize BLyS activity. Further optimization of PT with computer-guided molecular design method to enhance its biopotency may be useful in developing new BLyS antagonists to treat BLyS-related autoimmune diseases.

  11. Blockade of catecholamine-induced growth by adrenergic and dopaminergic receptor antagonists in Escherichia coli O157:H7, Salmonella enterica and Yersinia enterocolitica

    Directory of Open Access Journals (Sweden)

    Lyte Mark


    Full Text Available Abstract Background The ability of catecholamines to stimulate bacterial growth was first demonstrated just over a decade ago. Little is still known however, concerning the nature of the putative bacterial adrenergic and/or dopaminergic receptor(s to which catecholamines (norepinephrine, epinephrine and dopamine may bind and exert their effects, or even whether the binding properties of such a receptor are similar between different species. Results Use of specific catecholamine receptor antagonists revealed that only α, and not β, adrenergic antagonists were capable of blocking norepinephrine and epinephrine-induced growth, while antagonism of dopamine-mediated growth was achieved with the use of a dopaminergic antagonist. Both adrenergic and dopaminergic antagonists were highly specific in their mechanism of action, which did not involve blockade of catecholamine-facilitated iron-acquisition. Use of radiolabeled norepinephrine suggested that the adrenergic antagonists could be acting by inhibiting catecholamine uptake. Conclusion The present data demonstrates that the ability of a specific pathogen to respond to a particular hormone is dependent upon the host anatomical region in which the pathogen causes disease as well as the neuroanatomical specificity to which production of the particular hormone is restricted; and that both are anatomically coincidental to each other. As such, the present report suggests that pathogens with a high degree of exclusivity to the gastrointestinal tract have evolved response systems to neuroendocrine hormones such as norepinephrine and dopamine, but not epinephrine, which are found with the enteric nervous system.

  12. Effects of GABA receptor antagonists on thresholds of P23H rat retinal ganglion cells to electrical stimulation of the retina (United States)

    Jensen, Ralph J.; Rizzo, Joseph F., III


    An electronic retinal prosthesis may provide useful vision for patients suffering from retinitis pigmentosa (RP). In animal models of RP, the amount of current needed to activate retinal ganglion cells (RGCs) is higher than in normal, healthy retinas. In this study, we sought to reduce the stimulation thresholds of RGCs in a degenerate rat model (P23H-line 1) by blocking GABA receptor mediated inhibition in the retina. We examined the effects of TPMPA, a GABAC receptor antagonist, and SR95531, a GABAA receptor antagonist, on the electrically evoked responses of RGCs to biphasic current pulses delivered to the subretinal surface through a 400 µm diameter electrode. Both TPMPA and SR95531 reduced the stimulation thresholds of ON-center RGCs on average by 15% and 20% respectively. Co-application of the two GABA receptor antagonists had the greatest effect, on average reducing stimulation thresholds by 32%. In addition, co-application of the two GABA receptor antagonists increased the magnitude of the electrically evoked responses on average three-fold. Neither TPMPA nor SR95531, applied alone or in combination, had consistent effects on the stimulation thresholds of OFF-center RGCs. We suggest that the effects of the GABA receptor antagonists on ON-center RGCs may be attributable to blockage of GABA receptors on the axon terminals of ON bipolar cells.

  13. Pyrazole antagonists of the CB1 receptor with reduced brain penetration. (United States)

    Fulp, Alan; Zhang, Yanan; Bortoff, Katherine; Seltzman, Herbert; Snyder, Rodney; Wiethe, Robert; Amato, George; Maitra, Rangan


    Type 1 cannabinoid receptor (CB1) antagonists might be useful for treating obesity, liver disease, metabolic syndrome, and dyslipidemias. Unfortunately, inhibition of CB1 in the central nervous system (CNS) produces adverse effects, including depression, anxiety and suicidal ideation in some patients, which led to withdrawal of the pyrazole inverse agonist rimonabant (SR141716A) from European markets. Efforts are underway to produce peripherally selective CB1 antagonists to circumvent CNS-associated adverse effects. In this study, novel analogs of rimonabant (1) were explored in which the 1-aminopiperidine group was switched to a 4-aminopiperidine, attached at the 4-amino position (5). The piperidine nitrogen was functionalized with carbamates, amides, and sulfonamides, providing compounds that are potent inverse agonists of hCB1 with good selectivity for hCB1 over hCB2. Select compounds were further studied using in vitro models of brain penetration, oral absorption and metabolic stability. Several compounds were identified with predicted minimal brain penetration and good metabolic stability. In vivo pharmacokinetic testing revealed that inverse agonist 8c is orally bioavailable and has vastly reduced brain penetration compared to rimonabant.

  14. Antagonistic spindle motors and MAPs regulate metaphase spindle length and chromosome segregation. (United States)

    Syrovatkina, Viktoriya; Fu, Chuanhai; Tran, Phong T


    Metaphase describes a phase of mitosis where chromosomes are attached and oriented on the bipolar spindle for subsequent segregation at anaphase. In diverse cell types, the metaphase spindle is maintained at characteristic constant length [1-3]. Metaphase spindle length is proposed to be regulated by a balance of pushing and pulling forces generated by distinct sets of spindle microtubules (MTs) and their interactions with motors and MT-associated proteins (MAPs). Spindle length is further proposed to be important for chromosome segregation fidelity, as cells with shorter- or longer-than-normal metaphase spindles, generated through deletion or inhibition of individual mitotic motors or MAPs, showed chromosome segregation defects. To test the force-balance model of spindle length control and its effect on chromosome segregation, we applied fast microfluidic temperature control with live-cell imaging to monitor the effect of deleting or switching off different combinations of antagonistic force contributors in the fission yeast metaphase spindle. We show that the spindle midzone proteins kinesin-5 cut7p and MT bundler ase1p contribute to outward-pushing forces and that the spindle kinetochore proteins kinesin-8 klp5/6p and dam1p contribute to inward-pulling forces. Removing these proteins individually led to aberrant metaphase spindle length and chromosome segregation defects. Removing these proteins in antagonistic combination rescued the defective spindle length and in some combinations also partially rescued chromosome segregation defects.

  15. X-ray structures define human P2X3 receptor gating cycle and antagonist action (United States)

    Mansoor, Steven E.; Lü, Wei; Oosterheert, Wout; Shekhar, Mrinal; Tajkhorshid, Emad; Gouaux, Eric


    P2X receptors are trimeric, non-selective cation channels activated by ATP that have important roles in the cardiovascular, neuronal and immune systems. Despite their central function in human physiology and although they are potential targets of therapeutic agents, there are no structures of human P2X receptors. The mechanisms of receptor desensitization and ion permeation, principles of antagonism, and complete structures of the pore-forming transmembrane domains of these receptors remain unclear. Here we report X-ray crystal structures of the human P2X3 receptor in apo/resting, agonist-bound/open-pore, agonist-bound/closed-pore/desensitized and antagonist-bound/closed states. The open state structure harbours an intracellular motif we term the ‘cytoplasmic cap’, which stabilizes the open state of the ion channel pore and creates lateral, phospholipid-lined cytoplasmic fenestrations for water and ion egress. The competitive antagonists TNP-ATP and A-317491 stabilize the apo/resting state and reveal the interactions responsible for competitive inhibition. These structures illuminate the conformational rearrangements that underlie P2X receptor gating and provide a foundation for the development of new pharmacological agents.

  16. MDM2 antagonist Nutlin-3a potentiates antitumour activity of cytotoxic drugs in sarcoma cell lines

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    Lothe Ragnhild A


    Full Text Available Abstract Background Frequent failure and severe side effects of current sarcoma therapy warrants new therapeutic approaches. The small-molecule MDM2 antagonist Nutlin-3a activates the p53 pathway and efficiently induces apoptosis in tumours with amplified MDM2 gene and overexpression of MDM2 protein. However, the majority of human sarcomas have normal level of MDM2 and the therapeutic potential of MDM2 antagonists in this group is still unclear. We have investigated if Nutlin-3a could be employed to augment the response to traditional therapy and/or reduce the genotoxic burden of chemotherapy. Methods A panel of sarcoma cell lines with different TP53 and MDM2 status were treated with Nutlin-3a combined with Doxorubicin, Methotrexate or Cisplatin, and their combination index determined. Results Clear synergism was observed when Doxorubicin and Nutlin-3a were combined in cell lines with wild-type TP53 and amplified MDM2, or with Methotrexate in both MDM2 normal and amplified sarcoma cell lines, allowing for up to tenfold reduction of cytotoxic drug dose. Interestingly, Nutlin-3a seemed to potentiate the effect of classical drugs as Doxorubicin and Cisplatin in cell lines with mutated TP53, but inhibited the effect of Methotrexate. Conclusion The use of Nutlin in combination with classical sarcoma chemotherapy shows promising preclinical potential, but since clear biomarkers are still lacking, clinical trials should be followed up with detailed tumour profiling.

  17. Lack of Association Between IL-1 Receptor Antagonist Gene 86bp VNTR Polymorphism and Leiomyoma

    Directory of Open Access Journals (Sweden)

    Mohammadoo Khorasani


    Full Text Available Background Uterine leiomyoma (ULs is the most common gynecological tumor and a significant health concern for many women .The interleukin-1 receptor antagonist (IL-1Ra is a naturally occurring cytokine inhibiting interleukin- 1 (IL-1 activity by binding to the IL-1 receptors without signal transduction. Objectives The aim of this study was to investigate the association between interleukin-1 receptor antagonist gene variable number of tandem repeat (VNTR polymorphism and ULs in women of the South- East of Iran. Patients and Methods A total number of 99 patients with leiomyoma and 102 controls were studied. Genotyping of IL-1Ra (VNTR polymorphism was determined by gel electrophoresis after PCR amplification. Frequency of alleles and genotypes in patients and control group was statistically analyzed using χ2 test or fisher exact test. Results The frequency of alleles 1, 2 and 3 of IL-1Ra VNTR polymorphism were %71, %27 and %22 in control group and %74, %20 and %6 in the ULs patients, respectively and there were no significant differences between these two groups. No statistically significant differences were observed between the frequency of IL-1Ra genotypes in the study and control groups. Conclusions This study showed that 86bp VNTR polymorphism of IL-1Ra gene is not associated with leiomyoma in the studied population.

  18. Synergism of ochratoxin B and calcium-channel antagonist verapamil caused mitochondrial dysfunction. (United States)

    Chatopadhyay, Pronobesh; Tariang, Banlumlang; Agnihotri, Amit; Veer, Vijay


    We examined the mechanism by which the ochratoxin B induced interaction with calcium-channel antagonist verapamil and mitochondrial dysfunction of the rat trachea in vitro experiment. The tracheas were cut into 2-3 mm wide rings and suspended in a tissue bath. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. Verapamil (1 × 10(-6) M) produced a concentration-dependent contraction response in rat's tracheal rings pre-contracted by acetylcholine. Incubation of rat's tracheal rings with the ochratoxin B significantly potentiated the contraction responses of verapamil. Verapamil and OTB accelerate the overloading of Ca(2+) in tracheal smooth muscle contributes the tissue toxicity as shown in electron microscopy and mitochondrial enzymes, through a mechanism that could involve perturbations of Ca(2+) homeostasis. These results proved that ochratoxin B is a potential vasoconstrictor mycotoxin with the presence of calcium-channel antagonist. In conclusion, disturbance of Ca(2+) homeostasis caused by OTA and plays a significant role in produces toxicity through mitochondrial enzyme inhibition.

  19. Antimicrobial activity of extracellular metabolites from antagonistic bacteria isolated from potato (Solanum phureja crops

    Directory of Open Access Journals (Sweden)

    Sinar David Granada García


    Full Text Available Microorganisms for biological control are capable of producing active compounds that inhibit the development of phytopathogens, constituting a promising tool toob tain active principles that could replace synthetic pesticides. This study evaluatedtheability of severalpotentialbiocontrol microorganismsto produce active extracellular metabolites. In vitro antagonistic capability of 50 bacterial isolates from rhizospheric soils of "criolla" potato (Solanum phureja was tested through dual culture in this plant with different plant pathogenic fungi and bacteria. Isolates that showed significantly higher antagonistic activity were fermented in liquid media and crude extracts from the supernatants had their biological activities assessed by optical density techniques. Inhibitory effecton tested pathogens was observed for concentrations between 0.5% and 1% of crude extracts. There was a correlation between the antimicrobial activity of extracts and the use of nutrient-rich media in bacteria fermentation. Using a bioguided method, a peptidic compound, active against Fusarium oxysporum, was obtained from the 7ANT04 strain (Pyrobaculum sp.. Analysis by nuclear magnetic resonance and liquid chromatography coupled to mass detector evidenced an 11-amino acid compound. Bioinformatic software using raw mass data confirmed the presence of a cyclic peptide conformed by 11 mostly non-standard amino acids.

  20. 土壤拮抗细菌的分离与抗植物病原真菌活性初步研究%Preliminary Study on Isolating Antagonistic Bacteria f rom Soil and Antagonistic Activity Against Plant Pathogens

    Institute of Scientific and Technical Information of China (English)

    刘春来; 李新民; 王爽; 夏吉星; 杨帆; 刘宇; 苏宝华


    为了分离筛选出土壤中对植物病原真菌具有拮抗作用的细菌,以4种土传病害病原菌为诱导菌株,采用土壤颗粒撒布法,从不同生态区农田土壤样本中分离得到55株拮抗细菌菌株。测定了部分拮抗菌株及发酵滤液对植物病原菌的拮抗作用。结果表明:分离获得的细菌菌株对病原真菌均表现出一定程度的抑制作用,其中对菜豆根腐病菌(Fusarium solani)、小麦赤霉病菌(Fusarium graminearum)、番茄枯萎病菌(Fusarium oxysporum)菌丝抑制率达60%以上的拮抗菌株,分别有1、12和8株。9株拮抗菌发酵滤液对大豆菌核病菌(Sclerotinia sclerotiorum)、水稻稻瘟病菌(Pyricularia grisea)、玉米大斑病菌(Setosphaeria turcica)、小麦根腐病菌(Bipolaris sorokiniana)、水稻恶苗病菌(Fusarium moniliforme)和马铃薯早疫病菌(Alternaria so‐lani)6种植物病原菌表现出较高的抑菌效果,其中YS7菌株发酵产物对玉米大斑病菌、小麦根腐病菌、水稻恶苗病菌均表现较强的抑菌活性,对玉米大斑病菌抑菌圈直径最大达到了56.2 mm。从抗菌谱上看,27株拮抗菌株代谢产物对4种以上的拮抗对象表现有抑菌活性,表明拮抗菌株代谢产物具有较为广谱的抑菌效果。%In order to screen antagonistic bacteria in soil for plant pathogens bio‐control .55 antagonistic bacteria strains were isolated from soil samples in different ecological regions by the soil sprinkling method baited with 4 soil borne diseases .Part of antagonistic bacteria strains were evaluated for the antagonistic activity against plant pathogens .The result showed that more than 60% mycelial inhibition against Fusarium solani ,Fusarium graminearum ,Fusarium oxysporum were 1 ,12 and 8 stains ,respectively .Fermentation filtrate of 9 antagonis‐tic bacteria strains showed higher inhibition effect for Sclerotinia sclerotiorum ,Pyricularia grisea

  1. Differential effects of platelets and platelet inhibition by ticagrelor on TLR2- and TLR4-mediated inflammatory responses

    NARCIS (Netherlands)

    Tunjungputri, R.N.; Ven, A.J.A.M. van der; Riksen, N.P.; Rongen, G.A.P.J.M.; Tacke, S.; Berg, T.N.A. van den; Fijnheer, R.; Gomes, M.E.; Dinarello, C.A.; Veerdonk, F.L. van de; Gasem, M.H.; Netea, M.G.; Joosten, L.A.B.; Groot, P.G. de; Mast, Q. de


    Platelets and platelet-monocyte interaction play an important role in inflammation. Both pro- and anti-inflammatory effects of platelet inhibition have been reported in animal models. This study aimed to investigate the effect of platelets and platelet inhibition by the new P2Y12 receptor antagonist

  2. Nitric oxide-dependent antiplatelet action of AT1-receptor antagonists in a pulmonary thromboembolism in mice. (United States)

    Matys, Tomasz; Kucharewicz, Iwona; Pawlak, Robert; Chabielska, Ewa; Domaniewski, Tomasz; Buczko, Wlodzimierz


    The aim of this study was to determine whether AT1-receptor antagonists could inhibit platelet activation-dependent pulmonary thromboembolism in mice and to investigate the involvement of nitric oxide in this action. Losartan, its active metabolite EXP3174, and valsartan given intraperitoneally 1 hour before the thrombotic challenge (in doses of 3, 10, or 30 mg/kg) protected mice from death or hind-limb paralysis in response to intravenous injection of a mixture of collagen and epinephrine; losartan was effective in all doses used, whereas EXP3174 and valsartan reduced mortality only in the two higher doses. The protective action of EXP3174 and valsartan was abolished when nitric oxide synthase was inhibited with l-NAME, whereas that of losartan was only partially reduced. Moreover, only losartan protected mice from death caused by intravenous injection of the thromboxane A2 mimetic U46619 and this action was preserved in l-NAME-pretreated animals. Our results demonstrate the ability of AT1-receptor antagonists to inhibit platelet activation in vivo in a nitric oxide-dependent mechanism. Stronger antiplatelet activity of losartan, most likely due to its blockade of thromboxane A2/prostaglandin H2 receptor, could be of potential clinical relevance, particularly in conditions in which synthesis of endogenous nitric oxide is impaired.

  3. The Apolipoprotein E Antagonistic Pleiotropy Hypothesis: Review and Recommendations

    Directory of Open Access Journals (Sweden)

    Elizabeth R. Tuminello


    Full Text Available Research on apolipoprotein E (APOE has consistently revealed a relationship between the gene's ε4 allele and risk for development of Alzheimer's disease (AD. However, research with younger populations of ε4 carriers has suggested that the APOE ε4 allele may in fact be beneficial in earlier ages and may only confer risk of cognitive decline later in life. Accordingly, we and others have proposed that APOE may represent an example of antagonistic pleiotropy. Antagonistic pleiotropy is an evolutionary biology concept that proposes certain genes or alleles that may differentially impact fitness during different life stages. We critically review this hypothesis in light of new research of the impact of APOE on cognition and neural integrity across the lifespan. We provide recommendations for the revision of the antagonistic pleiotropy hypothesis of APOE and suggest important avenues for future research in this area.

  4. Discovery of the improved antagonistic prolactin variants by library screening. (United States)

    Liu, Yun; Gong, Wei; Breinholt, Jens; Nørskov-Lauritsen, Leif; Zhang, Jinchao; Ma, Qinhong; Chen, Jianhe; Panina, Svetlana; Guo, Wei; Li, Tengkun; Zhang, Jingyuan; Kong, Meng; Liu, Zibing; Mao, Jingjing; Christensen, Leif; Hu, Sean; Wang, Lingyun


    Prolactin (PRL), a potent growth stimulator of the mammary epithelium, has been suggested to be a factor contributing to the development and progression of breast and prostate cancer. Several PRL receptor (PRLR) antagonists have been identified in the past decades, but their in vivo growth inhibitory potency was restricted by low receptor affinity, rendering them pharmacologically unattractive for clinical treatment. Thus, higher receptor affinity is essential for the development of improved PRLR antagonistic variants with improved in vivo potency. In this study, we generated Site 1 focused protein libraries of human G129R-PRL mutants and screened for those with increased affinity to the human PRLR. By combining the mutations with enhanced affinities for PRLR, we identified a novel G129R-PRL variant with mutations at Site 1 that render nearly 50-fold increase in the antagonistic potency in vitro.


    Directory of Open Access Journals (Sweden)



    Full Text Available Schizophyllum commune Fr., is one of the important fungi, causes brown germ and seed rot of oil palm. Biodiversity of antagonistic bacteria from oil palm plantations in Peninsular Malaysia is expected to support in development of biopesticide. Isolation with liquid assay and screening antagonistic bacteria using dual culture assay were carried out in the bioexploration. A total of 265 bacterial isolates from plant parts of oil palm screened 52 antagonistic bacterial isolates against 5. commune. Bacterial isolates were identified by using Biolog* Identification System i.e. Bacillus macroccanus, B. thermoglucosidasius, Burkholderia cepacia, B. gladioli, B. multivorans, B pyrrocinia, B. spinosa, Corynebacterium agropyri, C. misitidis, Enterobacter aerogenes, Microbacterium testaceum, Pseudomonas aeruginosa, P. citronellolis, Rhodococcus rhodochrous, Serratia ficaria, Serratia sp., S. marcescens, Staphylococcus sciuri, Sternotrophomonas maltophilia.

  6. Neuroprotective Effects of Glutamate Antagonists and Extracellular Acidity (United States)

    Kaku, David A.; Giffard, Rona G.; Choi, Dennis W.


    Glutamate antagonists protect neurons from hypoxic injury both in vivo and in vitro, but in vitro studies have not been done under the acidic conditions typical of hypoxia-ischemia in vivo. Consistent with glutamate receptor antagonism, extracellular acidity reduced neuronal death in murine cortical cultures that were deprived of oxygen and glucose. Under these acid conditions, N-methyl-D-aspartate and α-amino-3-hydroxy-5-methyl-4-isox-azolepropionate-kainate antagonists further reduced neuronal death, such that some neurons tolerated prolonged oxygen and glucose deprivation almost as well as did astrocytes. Neuroprotection induced by this combination exceeded that induced by glutamate antagonists alone, suggesting that extracellular acidity has beneficial effects beyond the attenuation of ionotropic glutamate receptor activation.

  7. First Irish birth following IVF therapy using antagonist protocol.

    LENUS (Irish Health Repository)

    Mocanu, E V


    BACKGROUND: During in vitro fertilization (IVF), the prevention of a premature LH surge was traditionally achieved using a gonadotrophin releasing hormone agonist (GnRH-a), and more recently, a GnRH antagonist. AIMS: We report a case of a 37 year old treated using the GnRH antagonist in a second completed cycle of IVF. METHODS: IVF was performed for primary infertility of 5-year duration due to frozen pelvis secondary to endometriosis. RESULTS: Following controlled ovarian hyperstimulation, oocyte recovery and fertilization, cleavage and transfer of two zygotes, a pregnancy established. A twin gestation was diagnosed at 7-weeks scan and pregnancy ended with the delivery of twin girls by emergency caesarean section. CONCLUSION: This is a first report of a delivery following IVF using the antagonist protocol in Ireland. Such therapy is patient friendly and its use should be introduced on a larger scale in clinical practice.

  8. Ursolic acid, an antagonist for transforming growth factor (TGF)-beta1. (United States)

    Murakami, Shigeru; Takashima, Hajime; Sato-Watanabe, Mariko; Chonan, Sumi; Yamamoto, Koji; Saitoh, Masako; Saito, Shiuji; Yoshimura, Hiromitsu; Sugawara, Koko; Yang, Junshan; Gao, Nannan; Zhang, Xinggao


    Transforming growth factor-beta (TGF-beta), a multifunctional cytokine which is involved in extracellular matrix modulation, has a major role in the pathogenesis and progression of fibrotic diseases. We now report the effects of ursolic acid on TGF-beta1 receptor binding and TGF-beta1-induced cellular functions in vitro. Ursolic acid inhibited [(125)I]-TGF-beta1 receptor binding to Balb/c 3T3 mouse fibroblasts with an IC(50) value of 6.9+/-0.8 microM. Ursolic acid dose-dependently recovered reduced proliferation of Minc Mv1Lu cells in the presence of 5 nM of TGF-beta1 and attenuated TGF-beta1-induced collagen synthesis and production in human fibroblasts. Molecular dynamics simulations suggest that ursolic acid may interact with the hydrophobic region of the dimeric interface and thereby inhibit the binding of TGF-beta1 to its receptor. All these findings taken together show that ursolic acid functions as an antagonist for TGF-beta1. This is the first report to show that a small molecule can inhibit TGF-beta1 receptor binding and influence functions of TGF-beta1.

  9. P2Y12-ADP receptor antagonists: Days of future and past

    Institute of Scientific and Technical Information of China (English)

    Marc Laine; Franck Paganelli; Laurent Bonello


    Antiplatelet therapy is the cornerstone of the therapeutic arsenal in coronary artery disease.Thanks to a better understanding in physiology,pharmacology and pharmacogenomics huge progress were made in the field of platelet reactivity inhibition thus allowing theexpansion of percutaneous coronary intervention.Stent implantation requires the combination of two antiplatelet agents acting in a synergistic way.Asprin inhibit the cyclo-oxygenase pathway of platelet activation while clopidogrel is a P2Y12 adenosine diphosphate(ADP)-receptor antagonist.This dual antiplatelet therapy has dramatically improved the prognosis of stented patients.However,due to pharmacological limitations of clopidogrel(interindividual variability in its biological efficacy,slow onset of action,mild platelet reactivity inhibition)ischemic recurrences remained high following stent implantation especially in acute coronary syndrome patients.Thus,more potent P2Y12-ADP receptor inhibitors were developped including prasugrel,ticagrelor and more recently cangrelor to overcome these pitfalls.These new agents reduced the rate of thrombotic events in acute coronary syndrome patients at the cost of an increased bleeding risk.The abundance in antiplatelet agents allow us to tailor our strategy based on the thrombotic/bleeding profile of each patient.Recently,the ACCOAST trial cast a doubt on the benefit of pre treatment in non-ST segment elevation acute coronary syndrome.The aim of the present review is to summarize the results of the main studies dealing with antiplatelet therapy in stented/acute coronary syndromes patients.

  10. JB-9322, a new selective histamine H2-receptor antagonist with potent gastric mucosal protective properties. (United States)

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


    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.

  11. Antagonistic action of Lactobacillus spp. against Staphylococcus aureus in cheese from Mompox - Colombia

    Directory of Open Access Journals (Sweden)

    Piedad M. Montero Castillo


    Full Text Available In the food industry, food preservation techniquesthat do not use chemical products are becoming more common.Therefore, the aim of this research was to evaluate the antagonisticactivity (antibiosis of lactic-acid bacterial strains againstpathogenic microorganisms. Lactic-acid bacterial strains wereisolated from layered cheese and a commercial product (yogurt;and the same was done with pathogenic bacteria solely fromlayered cheese. The lactic-acid bacterial strains were identified asspecies from the Lactobacilli family, while the pathogenic bacteriafrom layered cheese were identified as Micrococcaceae familyspecies (Staphylococcus aureus. Subsequently, in the sameculture medium, bacteria of each species were sowed in order todetermine the inhibitory activity ability of the Lactic Acid Bacteria(BAL As a result, the highly antagonistic activity of the Lactobacilli(inhibition halos were larger than 0.5 centimeters in diameteragainst isolated pathogenic microorganisms was demonstrated.

  12. Characterization of SB-269970-A, a selective 5-HT7 receptor antagonist


    Hagan, Jim J.; Price, Gary W; Jeffrey, Phillip; Deeks, Nigel J; Stean, Tania; Piper, David; Smith, Martin I; Upton, Neil; Medhurst, Andrew D; Middlemiss, Derek N; Riley, Graham J; Lovell, Peter J; Bromidge, Steven M; Thomas, David R.


    The novel 5-HT7 receptor antagonist, SB-269970-A, potently displaced [3H]-5-CT from human 5-HT7(a) (pKi 8.9±0.1) and 5-HT7 receptors in guinea-pig cortex (pKi 8.3±0.2).5-CT stimulated adenylyl cyclase activity in 5-HT7(a)/HEK293 membranes (pEC50 7.5±0.1) and SB-269970-A (0.03–1 μM) inhibited the 5-CT concentration-response with no significant alteration in the maximal response. The pA2 (8.5±0.2) for SB-269970-A agreed well with the pKi determined from [3H]-5-CT binding studies.5-CT-stimulated...

  13. Enhanced bradycardia induced by beta-adrenoceptor antagonists in rats pretreated with isoniazid. (United States)

    Vidrio, H; Sánchez-Salvatori, M A; Medina, M


    High doses of isoniazid increase hypotension induced by vasodilators and change the accompanying reflex tachycardia to bradycardia, an interaction attributed to decreased synthesis of brain gamma-aminobutyric acid (GABA). In the present study, the possible enhancement by isoniazid of bradycardia induced by beta-adrenoceptor antagonists was determined in rats anaesthetised with chloralose-urethane. Isoniazid significantly increased bradycardia after propranolol, pindolol, labetalol and atenolol, as well as after clonidine, but not after hexamethonium or carbachol. Enhancement was not observed in rats pretreated with methylatropine or previously vagotomised. These results are compatible with interference by isoniazid with GABAergic inhibition of cardiac parasympathetic tone. Such interference could be exerted centrally, possibly at the nucleus ambiguus, or peripherally at the sinus node.

  14. Development and characterization of high affinity leptins and leptin antagonists. (United States)

    Shpilman, Michal; Niv-Spector, Leonora; Katz, Meirav; Varol, Chen; Solomon, Gili; Ayalon-Soffer, Michal; Boder, Eric; Halpern, Zamir; Elinav, Eran; Gertler, Arieh


    Leptin is a pleiotropic hormone acting both centrally and peripherally. It participates in a variety of biological processes, including energy metabolism, reproduction, and modulation of the immune response. So far, structural elements affecting leptin binding to its receptor remain unknown. We employed random mutagenesis of leptin, followed by selection of high affinity mutants by yeast surface display and discovered that replacing residue Asp-23 with a non-negatively charged amino acid leads to dramatically enhanced affinity of leptin for its soluble receptor. Rational mutagenesis of Asp-23 revealed the D23L substitution to be most effective. Coupling the Asp-23 mutation with alanine mutagenesis of three amino acids (L39A/D40A/F41A) previously reported to convert leptin into antagonist resulted in potent antagonistic activity. These novel superactive mouse and human leptin antagonists (D23L/L39A/D40A/F41A), termed SMLA and SHLA, respectively, exhibited over 60-fold increased binding to leptin receptor and 14-fold higher antagonistic activity in vitro relative to the L39A/D40A/F41A mutants. To prolong and enhance in vivo activity, SMLA and SHLA were monopegylated mainly at the N terminus. Administration of the pegylated SMLA to mice resulted in a remarkably rapid, significant, and reversible 27-fold more potent increase in body weight (as compared with pegylated mouse leptin antagonist), because of increased food consumption. Thus, recognition and mutagenesis of Asp-23 enabled construction of novel compounds that induce potent and reversible central and peripheral leptin deficiency. In addition to enhancing our understanding of leptin interactions with its receptor, these antagonists enable in vivo study of the role of leptin in metabolic and immune processes and hold potential for future therapeutic use in disease pathologies involving leptin.

  15. Development and Characterization of High Affinity Leptins and Leptin Antagonists* (United States)

    Shpilman, Michal; Niv-Spector, Leonora; Katz, Meirav; Varol, Chen; Solomon, Gili; Ayalon-Soffer, Michal; Boder, Eric; Halpern, Zamir; Elinav, Eran; Gertler, Arieh


    Leptin is a pleiotropic hormone acting both centrally and peripherally. It participates in a variety of biological processes, including energy metabolism, reproduction, and modulation of the immune response. So far, structural elements affecting leptin binding to its receptor remain unknown. We employed random mutagenesis of leptin, followed by selection of high affinity mutants by yeast surface display and discovered that replacing residue Asp-23 with a non-negatively charged amino acid leads to dramatically enhanced affinity of leptin for its soluble receptor. Rational mutagenesis of Asp-23 revealed the D23L substitution to be most effective. Coupling the Asp-23 mutation with alanine mutagenesis of three amino acids (L39A/D40A/F41A) previously reported to convert leptin into antagonist resulted in potent antagonistic activity. These novel superactive mouse and human leptin antagonists (D23L/L39A/D40A/F41A), termed SMLA and SHLA, respectively, exhibited over 60-fold increased binding to leptin receptor and 14-fold higher antagonistic activity in vitro relative to the L39A/D40A/F41A mutants. To prolong and enhance in vivo activity, SMLA and SHLA were monopegylated mainly at the N terminus. Administration of the pegylated SMLA to mice resulted in a remarkably rapid, significant, and reversible 27-fold more potent increase in body weight (as compared with pegylated mouse leptin antagonist), because of increased food consumption. Thus, recognition and mutagenesis of Asp-23 enabled construction of novel compounds that induce potent and reversible central and peripheral leptin deficiency. In addition to enhancing our understanding of leptin interactions with its receptor, these antagonists enable in vivo study of the role of leptin in metabolic and immune processes and hold potential for future therapeutic use in disease pathologies involving leptin. PMID:21119198

  16. Fevipiprant (QAW039), a Slowly Dissociating CRTh2 Antagonist with the Potential for Improved Clinical Efficacy. (United States)

    Sykes, David A; Bradley, Michelle E; Riddy, Darren M; Willard, Elizabeth; Reilly, John; Miah, Asadh; Bauer, Carsten; Watson, Simon J; Sandham, David A; Dubois, Gerald; Charlton, Steven J


    Here we describe the pharmacologic properties of a series of clinically relevant chemoattractant receptor-homologous molecules expressed on T-helper type 2 (CRTh2) receptor antagonists, including fevipiprant (NVP-QAW039 or QAW039), which is currently in development for the treatment of allergic diseases. [(3)H]-QAW039 displayed high affinity for the human CRTh2 receptor (1.14 ± 0.44 nM) expressed in Chinese hamster ovary cells, the binding being reversible and competitive with the native agonist prostaglandin D2(PGD2). The binding kinetics of QAW039 determined directly using [(3)H]-QAW039 revealed mean kinetic on (kon) and off (koff) values for QAW039 of 4.5 × 10(7)M(-1)min(-1)and 0.048 minute(-1), respectively. Importantly, thekoffof QAW039 (half-life = 14.4 minutes) was >7-fold slower than the slowest reference compound tested, AZD-1981. In functional studies, QAW039 behaved as an insurmountable antagonist of PGD2-stimulated [(35)S]-GTPγS activation, and its effects were not fully reversed by increasing concentrations of PGD2after an initial 15-minute incubation period. This behavior is consistent with its relatively slow dissociation from the human CRTh2 receptor. In contrast for the other ligands tested this time-dependent effect on maximal stimulation was fully reversed by the 15-minute time point, whereas QAW039's effects persisted for >180 minutes. All CRTh2 antagonists tested inhibited PGD2-stimulated human eosinophil shape change, but importantly QAW039 retained its potency in the whole-blood shape-change assay relative to the isolated shape change assay, potentially reflective of its relatively slower off rate from the CRTh2 receptor. QAW039 was also a potent inhibitor of PGD2-induced cytokine release in human Th2 cells. Slow CRTh2 antagonist dissociation could provide increased receptor coverage in the face of pathologic PGD2concentrations, which may be clinically relevant.

  17. Interleukin-1-receptor antagonist in type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Larsen, Claus M; Faulenbach, Mirjam; Vaag, Allan


    BACKGROUND: The expression of interleukin-1-receptor antagonist is reduced in pancreatic islets of patients with type 2 diabetes mellitus, and high glucose concentrations induce the production of interleukin-1beta in human pancreatic beta cells, leading to impaired insulin secretion, decreased cell...... proliferation, and apoptosis. METHODS: In this double-blind, parallel-group trial involving 70 patients with type 2 diabetes, we randomly assigned 34 patients to receive 100 mg of anakinra (a recombinant human interleukin-1-receptor antagonist) subcutaneously once daily for 13 weeks and 36 patients to receive...

  18. Barnidipine, a long-acting slow onset calcium antagonist. (United States)

    Korstanje, C


    Barnidipine is a stereochemically pure dihydropyridine calcium antagonist with a high potency. The drug showed a slow onset and long-lasting vasorelaxating effect in vitro, and strong antihypertensive activity in hypertension models. Barnidipine was shown to have a high vasoselectivity and offered protection in cardiac and renal ischaemia models. The in vitro drug:drug interaction profile suggests a low potential for clinically relevant interactions with concomitant medication. It can be anticipated that barnidipine is an attractive calcium antagonist, offering good blood pressure control without compensatory baroreflex activity.

  19. Hyperglycemia of Diabetic Rats Decreased by a Glucagon Receptor Antagonist (United States)

    Johnson, David G.; Ulichny Goebel, Camy; Hruby, Victor J.; Bregman, Marvin D.; Trivedi, Dev


    The glucagon analog [l-Nα-trinitrophenylhistidine, 12-homoarginine]-glucagon (THG) was examined for its ability to lower blood glucose concentrations in rats made diabetic with streptozotocin. In vitro, THG is a potent antagonist of glucagon activation of the hepatic adenylate cyclase assay system. Intravenous bolus injections of THG caused rapid decreases (20 to 35 percent) of short duration in blood glucose. Continuous infusion of low concentrations of the inhibitor led to larger sustained decreases in blood glucose (30 to 65 percent). These studies demonstrate that a glucagon receptor antagonist can substantially reduce blood glucose levels in diabetic animals without addition of exogenous insulin.

  20. Salvianolic Acid A, as a Novel ETA Receptor Antagonist, Shows Inhibitory Effects on Tumor in Vitro

    Directory of Open Access Journals (Sweden)

    Qiao Zhang


    Full Text Available Endothelin-1 (ET-1 autocrine and paracrine signaling modulate cell proliferation of tumor cells by activating its receptors, endothelin A receptor (ETAR and endothelin B receptor (ETBR. Dysregulation of ETAR activation promotes tumor development and progression. The potential of ETAR antagonists and the dual-ETAR and ETBR antagonists as therapeutic approaches are under preclinical and clinical studies. Salvianolic acid A (Sal A is a hydrophilic polyphenolic derivative isolated from Salvia miltiorrhiza Bunge (Danshen, which has been reported as an anti-cancer and cardio-protective herbal medicine. In this study, we demonstrate that Sal A inhibits ETAR activation induced by ET-1 in both recombinant and endogenous ETAR expression cell lines. The IC50 values were determined as 5.7 µM in the HEK293/ETAR cell line and 3.14 µM in HeLa cells, respectively. Furthermore, our results showed that Sal A suppressed cell proliferation and extended the doubling times of multiple cancer cells, including HeLa, DU145, H1975, and A549 cell lines. In addition, Sal A inhibited proliferation of DU145 cell lines stimulated by exogenous ET-1 treatment. Moreover, the cytotoxicity and cardio-toxicity of Sal A were assessed in human umbilical vein endothelial cells (HUVEC and Human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs, which proved that Sal A demonstrates no cytotoxicity or cardiotoxicity. Collectively, our findings indicate that Sal A is a novel anti-cancer candidate through targeting ETAR.

  1. Rational design of an auxin antagonist of the SCF(TIR1) auxin receptor complex. (United States)

    Hayashi, Ken-ichiro; Neve, Joshua; Hirose, Masakazu; Kuboki, Atsuhito; Shimada, Yukihisa; Kepinski, Stefan; Nozaki, Hiroshi


    The plant hormone auxin is a master regulator of plant growth and development. By regulating rates of cell division and elongation and triggering specific patterning events, indole 3-acetic acid (IAA) regulates almost every aspect of plant development. The perception of auxin involves the formation of a ternary complex consisting of an F-box protein of the TIR1/AFB family of auxin receptors, the auxin molecule, and a member the Aux/IAA family of co-repressor proteins. In this study, we identified a potent auxin antagonist, α-(phenylethyl-2-oxo)-IAA, as a lead compound for TIR1/AFB receptors by in silico virtual screening. This molecule was used as the basis for the development of a more potent TIR1 antagonist, auxinole (α-[2,4-dimethylphenylethyl-2-oxo]-IAA), using a structure-based drug design approach. Auxinole binds TIR1 to block the formation of the TIR1-IAA-Aux/IAA complex and so inhibits auxin-responsive gene expression. Molecular docking analysis indicates that the phenyl ring in auxinole would strongly interact with Phe82 of TIR1, a residue that is crucial for Aux/IAA recognition. Consistent with this predicted mode of action, auxinole competitively inhibits various auxin responses in planta. Additionally, auxinole blocks auxin responses of the moss Physcomitrella patens, suggesting activity over a broad range of species. Our works not only substantiates the utility of chemical tools for plant biology but also demonstrates a new class of small molecule inhibitor of protein-protein interactions common to mechanisms of perception of other plant hormones, such as jasmonate, gibberellin, and abscisic acid.

  2. Structure of CC chemokine receptor 2 with orthosteric and allosteric antagonists

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yi; Qin, Ling; Ortiz Zacarías, Natalia V.; de Vries, Henk; Han, Gye Won; Gustavsson, Martin; Dabros, Marta; Zhao, Chunxia; Cherney, Robert J.; Carter, Percy; Stamos, Dean; Abagyan, Ruben; Cherezov, Vadim; Stevens, Raymond C.; IJzerman, Adriaan P.; Heitman, Laura H.; Tebben, Andrew; Kufareva, Irina; Handel , Tracy M. (Vertex Pharm); (Leiden-MC); (USC); (BMS); (UCSD)


    CC chemokine receptor 2 (CCR2) is one of 19 members of the chemokine receptor subfamily of human class A G-protein-coupled receptors. CCR2 is expressed on monocytes, immature dendritic cells, and T-cell subpopulations, and mediates their migration towards endogenous CC chemokine ligands such as CCL2 (ref. 1). CCR2 and its ligands are implicated in numerous inflammatory and neurodegenerative diseases2 including atherosclerosis, multiple sclerosis, asthma, neuropathic pain, and diabetic nephropathy, as well as cancer3. These disease associations have motivated numerous preclinical studies and clinical trials4 (see in search of therapies that target the CCR2–chemokine axis. To aid drug discovery efforts5, here we solve a structure of CCR2 in a ternary complex with an orthosteric (BMS-681 (ref. 6)) and allosteric (CCR2-RA-[R]7) antagonist. BMS-681 inhibits chemokine binding by occupying the orthosteric pocket of the receptor in a previously unseen binding mode. CCR2-RA-[R] binds in a novel, highly druggable pocket that is the most intracellular allosteric site observed in class A G-protein-coupled receptors so far; this site spatially overlaps the G-protein-binding site in homologous receptors. CCR2-RA-[R] inhibits CCR2 non-competitively by blocking activation-associated conformational changes and formation of the G-protein-binding interface. The conformational signature of the conserved microswitch residues observed in double-antagonist-bound CCR2 resembles the most inactive G-protein-coupled receptor structures solved so far. Like other protein–protein interactions, receptor–chemokine complexes are considered challenging therapeutic targets for small molecules, and the present structure suggests diverse pocket epitopes that can be exploited to overcome obstacles in drug design.

  3. A Comparative Docking Study of Anibamine as the First Natural Product CCR5 Antagonist in CCR5 Homology Models



    Anibamine, a novel pyridine quaternary alkaloid recently isolated from Aniba sp., has been found to effectively bind to the chemokine receptor CCR5 with an IC50 at 1 μM in competition with 125I-gp120, an HIV viral envelope protein binding to CCR5 with high affinity. Since CCR5, a G-protein-coupled receptor, is an essential co-receptor for the human immunodeficiency virus type I (HIV-1) entry to host cells, a CCR5 antagonist that inhibits the cellular entry of HIV-1 provides a new therapy choi...

  4. Filamentous fungi isolated from grape marc as antagonists of Botrytis cinerea

    Directory of Open Access Journals (Sweden)

    Jovičić-Petrović Jelena P.


    Full Text Available In this paper we report on the isolation and identification of three filamentous fungi from grape marc, and antifungal effect of their cell-free culture filtrates on the growth of Botrytis cinerea, causal agent of gray mold. Grape marc is a waste material that has been used as soil amendment in sustainable agriculture. Isolates originating from grape marc were identified on the basis of morphological features and internal transcribed spacer rDNA or β-tubulin gene sequencing. The presence of three different species, Penicillium paneum, Penicillium chrysogenum and Aspergillus fumigatus has been detected expressing different effect on the growth of B. cinerea. The effect of crude culture filtrates of selected fungi on B. cinerea growth was tested. Heat sensitivity of the established inhibition effect was examined by autoclaving the crude culture filtrate prior to testing. Additional aim was to determine whether antifungal effect was influenced by previous exposure to B. cinerea in dual liquid cultures. Crude culture filtrate of A. fumigatus K16/2 showed the lowest suppression of B. cinerea growth. A maximal percentage inhibition achieved within the study was 38.2%, 39.8% and 23.8 for crude filtrates of P. paneum K7/1, P. chrysogenum K11/1 and A. fumigatus K16/2, respectively. Presence of B. cinerea in dual liquid culture induced significant increase in antifungal capacity of the culture filtrates in comparison to pure culture filtrates of the chosen isolates. The antifungal activity of all of the isolates’ culture filtrates retained after heat treatment suggesting the presence of some thermostable antifungal metabolites. The results indicate the complexity and specificity of the interaction between filamentous fungi and B. cinerea. Grape marc is a good source for isolation od B. cinerea fungal antagonists and their antifungal metabolites. Specificity of fungal-fungal interactions suggests that further research on the antagonistic mechanisms and


    Directory of Open Access Journals (Sweden)

    Samikan Krishnakumar


    Full Text Available Indigenous rhizosphere soil samples were collected during study period (October 2011 – March 2012 of different crop plant from Thiruvannamalai District, Tamilnadu, India for the enumeration of Phosphate solubilizing microorganisms (PSMs. Efficient phosphate solubilizing bacteria, fungi and heterotrophic bacteria were enumerated. Maximum heterotrophic bacterial populations (19.4 X105, phosphate solubilizing bacteria (4.7 X 105 were recorded in the month of February and phosphate solubilizing fungi (3.9 X 102 were documented in the month of December in rhizosphere soil of ground nut. Minimum bacterial populations (14.3 X 105 were observed in rhizosphere soil of chilli in the month of March. Lowest phosphate solubilizing bacteria (1.2 X105 and phosphate solubilzing fungi (1.2 X 102 were observed in rhizosphere soil of paddy during the month of October. Phosphate solubilizing bacteria Pseudomonassp. - BS1, Bacillus sp. – BS2, Micrococcus sp. – BS3 and fungi Aspergillus sp. – FS1, Penicillium sp. – FS2.and Trichoderma sp. – FS3 were identified. Pseudomonas sp. - BS1. exhibited maximum solubilizing efficiency (SE and solubilizing index (SI of 300.0 and 4.0 respectively. In fungi Aspergillus sp. – FS1 showed a maximum solubilizing efficiency (SE and solubilizing index(SI of 283.3 and 3.8 respectively. Antagonistic activity of P-solubilizing Pseudomonassp. - BS1 was deliberated against selected fungal plant pathogens. Among pathogens studied Aspergillus sp. showed a maximum inhibition activity (16 mm and minimum activity (12 mm was observed against Fusarium sp. Moreover inhibition efficiency (IE and inhibition index (II of Pseudomonas sp. - BS1. also calculated base on the antagonistic activity. Aspergillus sp. exhibited highest inhibition efficiency and inhibition index of 166.6 and 3.6 respectively.

  6. Vasoactive intestinal peptide antagonist treatment during mouse embryogenesis impairs social behavior and cognitive function of adult male offspring. (United States)

    Hill, Joanna M; Cuasay, Katrina; Abebe, Daniel T


    Vasoactive intestinal peptide (VIP) is a regulator of rodent embryogenesis during the period of neural tube closure. VIP enhanced growth in whole cultured mouse embryos; treatment with a VIP antagonist during embryogenesis inhibited growth and development. VIP antagonist treatment during embryogenesis also had permanent effects on adult brain chemistry and impaired social recognition behavior in adult male mice. The neurological deficits of autism appear to be initiated during neural tube closure and social behavior deficits are among the key characteristics of this disorder that is more common in males and is frequently accompanied by mental retardation. The current study examined the blockage of VIP during embryogenesis as a model for the behavioral deficits of autism. Treatment of pregnant mice with a VIP antagonist during embryonic days 8 through 10 had no apparent effect on the general health or sensory or motor capabilities of adult offspring. However, male offspring exhibited reduced sociability in the social approach task and deficits in cognitive function, as assessed through cued and contextual fear conditioning. Female offspring did not show these deficiencies. These results suggest that this paradigm has usefulness as a mouse model for aspects of autism as it selectively impairs male offspring who exhibit the reduced social behavior and cognitive dysfunction seen in autism. Furthermore, the study indicates that the foundations of some aspects of social behavior are laid down early in mouse embryogenesis, are regulated in a sex specific manner and that interference with embryonic regulators such as VIP can have permanent effects on adult social behavior.

  7. Effects of calcium channel antagonists on the induction of nitric oxide synthase in cultured cells by immunostimulants. (United States)

    Hattori, Y; Kasai, K; So, S; Hattori, S; Banba, N; Shimoda, S


    We investigated whether calcium channel antagonists would alter the induction of nitric oxide (NO) synthesis by bacterial lipopolysaccharide (LPS) alone or in combination with interferon-gamma (IFN gamma) in cultured J774 macrophages, rat vascular smooth muscle cells, rat renal mesangial cells, and rat cardiac myocytes. The induction of NO synthesis was determined by measuring nitrite, the stable end-product. The dihydropyridine calcium channel antagonists, nifedipine, manidipine, nitrendipine, benidipine, barnidipine, perdipine, and nilvadipine all reduced the LPS-induced nitrite production in a dose-dependent manner, each with a differing half-maximal inhibitory concentration, in cultured J774 macrophages. Nifedipine also inhibited nitrite production in vascular smooth muscle cells, mesangial cells, and cardiac myocytes. The half-maximal inhibitory concentrations of nifedipine were ranked as follows: smooth muscle cells < mesangial cells < cardiac myocytes. Diltiazem, at nontoxic concentrations, had no effect on the nitrite formation in the three cell types. Verapamil markedly increased the formation of nitrite in cardiac myocytes in response to LPS and IFN gamma, but not in vascular smooth muscle or mesangial cells. Exposure of cardiac myocytes to LPS and IFN gamma caused the expression of NO synthase mRNA that was significantly increased by verapamil. Thus, certain calcium channel antagonists modulate NO synthesis by altering the induction of NO synthase.

  8. Effects of a 5-HT3 antagonist, ondansetron, on fasting and postprandial small bowel water content assessed by magnetic resonance imaging



    Abstract Background 5-HT3 antagonists have been shown to be effective in relieving symptoms of IBS-D. Using a recently validated MRI method we have demonstrated reduced fasting small bowel water content (SBWC) in IBS-D associated with accelerated small bowel transit. We hypothesized that slowing of transit with ondansetron would lead to an increase in SBWC by inhibiting fasting motility. Aim To assess the effects of ondansetron compared with placebo in healthy volunteers o...

  9. Cross-domain inhibition of TACE ectodomain

    DEFF Research Database (Denmark)

    Tape, Christopher J; Willems, Sofie H; Dombernowsky, Sarah L;


    Proteolytic release from the cell surface is an essential activation event for many growth factors and cytokines. TNF-a converting enzyme (TACE) is a membrane-bound metalloprotease responsible for solubilizing many pathologically significant membrane substrates and is an attractive therapeutic...... target for the treatment of cancer and arthritis. Prior attempts to antagonize cell-surface TACE activity have focused on small-molecule inhibition of the metalloprotease active site. Given the highly conserved nature of metalloprotease active sites, this paradigm has failed to produce a truly specific...... individual antibody variable domains to desired epitopes. The resulting "cross-domain" human antibody is a previously undescribed selective TACE antagonist and provides a unique alternative to small-molecule metalloprotease inhibition....

  10. 5-Hydroxytryptamine3 receptor antagonists and cardiac side effects

    DEFF Research Database (Denmark)

    Brygger, Louise; Herrstedt, Jørn


    INTRODUCTION: 5-Hydroxytryptamine3-receptor antagonists (5-HT3-RA) are the most widely used antiemetics in oncology, and although tolerability is high, QTC prolongation has been observed in some patients. AREAS COVERED: The purpose of this article is to outline the risk of cardiac adverse events...

  11. Voltage-Gated Calcium Channel Antagonists and Traumatic Brain Injury

    Directory of Open Access Journals (Sweden)

    Bruce Lyeth


    Full Text Available Traumatic brain injury (TBI is a leading cause of death and disability in the United States. Despite more than 30 years of research, no pharmacological agents have been identified that improve neurological function following TBI. However, several lines of research described in this review provide support for further development of voltage gated calcium channel (VGCC antagonists as potential therapeutic agents. Following TBI, neurons and astrocytes experience a rapid and sometimes enduring increase in intracellular calcium ([Ca2+]i. These fluxes in [Ca2+]i drive not only apoptotic and necrotic cell death, but also can lead to long-term cell dysfunction in surviving cells. In a limited number of in vitro experiments, both L-type and N-type VGCC antagonists successfully reduced calcium loads as well as neuronal and astrocytic cell death following mechanical injury. In rodent models of TBI, administration of VGCC antagonists reduced cell death and improved cognitive function. It is clear that there is a critical need to find effective therapeutics and rational drug delivery strategies for the management and treatment of TBI, and we believe that further investigation of VGCC antagonists should be pursued before ruling out the possibility of successful translation to the clinic.

  12. How Hybrid Organizations Turn Antagonistic Assets into Complementarities

    DEFF Research Database (Denmark)

    Hockerts, Kai


    This article focuses on people excluded from traditional markets as employees, producers, or consumers on the grounds that they lack the appropriate skills. It describes the processes through which these perceived liabilities can be overcome by so-called hybrid organizations. Hybrids pursue expli...... for complementarities, and by creating demands for antagonistic assets, or by using partnerships....

  13. Serotonin 2A receptor antagonists for treatment of schizophrenia

    DEFF Research Database (Denmark)

    Ebdrup, Bjørn Hylsebeck; Rasmussen, Hans; Arnt, Jørn;


    Introduction: All approved antipsychotic drugs share an affinity for the dopamine 2 (D2) receptor; however, these drugs only partially ameliorate the symptoms of schizophrenia. It is, therefore, of paramount importance to identify new treatment strategies for schizophrenia. Areas covered: Preclin......Introduction: All approved antipsychotic drugs share an affinity for the dopamine 2 (D2) receptor; however, these drugs only partially ameliorate the symptoms of schizophrenia. It is, therefore, of paramount importance to identify new treatment strategies for schizophrenia. Areas covered...... receptor antagonists is evaluated. Moreover, the investigational pipeline of major pharmaceutical companies is examined and an Internet search conducted to identify other pharmaceutical companies investigating 5-HT2A receptor antagonists for the treatment of schizophrenia. Expert opinion: 5-HT2A receptor...... antagonists appear to assume an intermediate position by being marginally superior to placebo but inferior to conventional antipsychotic drugs. Three previous 5-HT2A receptor antagonists have been discontinued after Phase II or III trials, and available Phase IIa data on the remaining 5-HT2A receptor...

  14. Facilitative and antagonistic interactions between plant viruses in mixed infections. (United States)

    Syller, Jerzy


    Mixed infections of plant viruses are common in nature, and a number of important virus diseases of plants are the outcomes of interactions between causative agents. Multiple infections lead to a variety of intrahost virus-virus interactions, many of which may result in the generation of variants showing novel genetic features, and thus change the genetic structure of the viral population. Hence, virus-virus interactions in plants may be of crucial significance for the understanding of viral pathogenesis and evolution, and consequently for the development of efficient and stable control strategies. The interactions between plant viruses in mixed infections are generally categorized as synergistic or antagonistic. Moreover, mixtures of synergistic and antagonistic interactions, creating usually unpredictable biological and epidemiological consequences, are likely to occur in plants. The mechanisms of some of these are still unknown. This review aims to bring together the current knowledge on the most commonly occurring facilitative and antagonistic interactions between related or unrelated viruses infecting the same host plant. The best characterized implications of these interactions for virus-vector-host relationships are included. The terms 'synergism' and 'helper dependence' for facilitative virus-virus interactions, and 'cross-protection' and 'mutual exclusion' for antagonistic interactions, are applied in this article.

  15. Determinants of effective, safe and convenient vitamin K antagonist use

    NARCIS (Netherlands)

    Kooistra, Hilde Afra Margaretha


    Vitamin K antagonists (VKA) are frequently used anticoagulants. They are very effective in preventing atrial fibrillation related strokes and recurrent venous thrombosis. However, it can be difficult to achieve an optimal balance between the efficacy and side effects (bleeding), as the dose response

  16. Reversal strategies for vitamin K antagonists in acute intracerebral hemorrhage

    NARCIS (Netherlands)

    Parry-Jones, A.R.; Napoli, M. Di; Goldstein, J.N.; Schreuder, F.H.; Tetri, S.; Tatlisumak, T.; Yan, B.; Nieuwenhuizen, K.M.; Dequatre-Ponchelle, N.; Lee-Archer, M.; Horstmann, S.; Wilson, D.; Pomero, F.; Masotti, L.; Lerpiniere, C.; Godoy, D.A.; Cohen, A.S.; Houben, R.; Al-Shahi Salman, R.; Pennati, P.; Fenoglio, L.; Werring, D.; Veltkamp, R.; Wood, E.; Dewey, H.M.; Cordonnier, C.; Klijn, C.J.M.; Meligeni, F.; Davis, S.M.; Huhtakangas, J.; Staals, J.; Rosand, J.; Meretoja, A.


    OBJECTIVE: There is little evidence to guide treatment strategies for intracerebral hemorrhage on vitamin K antagonists (VKA-ICH). Treatments utilized in clinical practice include fresh frozen plasma (FFP) and prothrombin complex concentrate (PCC). Our aim was to compare case fatality with different

  17. Reversal strategies for vitamin K antagonists in acute intracerebral hemorrhage

    NARCIS (Netherlands)

    Parry-Jones, Adrian R.; Di Napoli, Mario; Goldstein, Joshua N.; Schreuder, Floris H B M; Tetri, Sami; Tatlisumak, Turgut; Yan, Bernard; Van Nieuwenhuizen, Koen M.; Dequatre-Ponchelle, Nelly; Lee-Archer, Matthew; Horstmann, Solveig; Wilson, Duncan; Pomero, Fulvio; Masotti, Luca; Lerpiniere, Christine; Godoy, Daniel Agustin; Cohen, Abigail S.; Houben, Rik; Al-Shahi Salman, Rustam; Pennati, Paolo; Fenoglio, Luigi; Werring, David; Veltkamp, Roland; Wood, Edith; Dewey, Helen M.; Cordonnier, Charlotte; Klijn, Catharina J M; Meligeni, Fabrizio; Davis, Stephen M.; Huhtakangas, Juha; Staals, Julie; Rosand, Jonathan; Meretoja, Atte


    Objective There is little evidence to guide treatment strategies for intracerebral hemorrhage on vitamin K antagonists (VKA-ICH). Treatments utilized in clinical practice include fresh frozen plasma (FFP) and prothrombin complex concentrate (PCC). Our aim was to compare case fatality with different

  18. Bronchoprotection with a leukotriene receptor antagonist in asthmatic preschool children

    DEFF Research Database (Denmark)

    Bisgaard, H; Nielsen, K G


    We hypothesized that a leukotriene receptor antagonist (LTRA) could provide bronchoprotection against the cold, dry air-induced response in asthmatic preschool children. In a randomized, double-blind, placebo-controlled crossover study, we examined the effect of the specific LTRA montelukast at 5...

  19. Does intergenerational social mobility affect antagonistic attitudes towards ethnic minorities?

    NARCIS (Netherlands)

    Tolsma, J.; Graaf, N.D. de; Quillian, L.


    Up till now, no study satisfactorily addressed the effect of social mobility on antagonistic attitudes toward ethnic minorities. In this contribution, we investigate the effect of educational and class intergenerational mobility on ethnic stereotypes, ethnic threat, and opposition to ethnic intermar

  20. Komplikationer til langtidsbehandling med vitamin K-antagonister

    DEFF Research Database (Denmark)

    May, O; Garne, E; Mickley, H


    Long-term treatment with vitamin K antagonists (vKA) frequently involves complications. The commonest complication is haemorrhage and cases of serious haemorrhage are stated in the literature to occur with a frequency per 1,000 treatment years of 12-108, of which 2-17 are fatal. The majority...

  1. Myofascial force transmission via extramuscular pathways occurs between antagonistic muscles. (United States)

    Huijing, Peter A; Baan, Guus C


    Most often muscles (as organs) are viewed as independent actuators. To test if this is true for antagonistic muscles, force was measured simultaneously at: (1) the proximal and distal tendons of the extensor digitorum muscle (EDL) to quantify any proximo-distal force differences, as an indicator of myofascial force transmission, (2) at the distal tendons of the whole antagonistic peroneal muscle group (PER) to test if effects of EDL length changes are present and (3) at the proximal end of the tibia to test if myofascially transmitted force is exerted there. EDL length was manipulated either at the proximal or distal tendons. This way equal EDL lengths are attained at two different positions of the muscle with respect to the tibia and antagonistic muscles. Despite its relatively small size, lengthening of the EDL changed forces exerted on the tibia and forces exerted by its antagonistic muscle group. Apart from its extramuscular myofascial connections, EDL has no connections to either the tibia or these antagonistic muscles. Proximal EDL lengthening increased distal muscular forces (active PER DeltaF approximately +1.7%), but decreased tibial forces (passive from 0.3 to 0 N; active DeltaF approximately -5%). Therefore, it is concluded that these antagonistic muscles do not act independently, because of myofascial force transmission between them. Such a decrease in tibial force indicates release of pre-strained connections. Distal EDL lengthening had opposite effects (tripling passive force exerted on tibia; active PER force DeltaF approximately -3.6%). It is concluded that the length and relative position of the EDL is a co-determinant of passive and active force exerted at tendons of nearby antagonistic muscle groups. These results necessitate a new view of the locomotor apparatus, which needs to take into account the high interdependence of muscles and muscle fibres as force generators, as well as proximo-distal force differences and serial and parallel

  2. Accumulation of Deleterious Mutations Near Sexually Antagonistic Genes

    Directory of Open Access Journals (Sweden)

    Tim Connallon


    Full Text Available Mutation generates a steady supply of genetic variation that, while occasionally useful for adaptation, is more often deleterious for fitness. Recent research has emphasized that the fitness effects of mutations often differ between the sexes, leading to important evolutionary consequences for the maintenance of genetic variation and long-term population viability. Some forms of sex-specific selection—i.e., stronger purifying selection in males than females—can help purge a population’s load of female-harming mutations and promote population growth. Other scenarios—e.g., sexually antagonistic selection, in which mutations that harm females are beneficial for males—inflate genetic loads and potentially dampen population viability. Evolutionary processes of sexual antagonism and purifying selection are likely to impact the evolutionary dynamics of different loci within a genome, yet theory has mostly ignored the potential for interactions between such loci to jointly shape the evolutionary genetic basis of female and male fitness variation. Here, we show that sexually antagonistic selection at a locus tends to elevate the frequencies of deleterious alleles at tightly linked loci that evolve under purifying selection. Moreover, haplotypes that segregate for different sexually antagonistic alleles accumulate different types of deleterious mutations. Haplotypes that carry female-benefit sexually antagonistic alleles preferentially accumulate mutations that are primarily male harming, whereas male-benefit haplotypes accumulate mutations that are primarily female harming. The theory predicts that sexually antagonistic selection should shape the genomic organization of genetic variation that differentially impacts female and male fitness, and contribute to sexual dimorphism in the genetic basis of fitness variation.

  3. Ubiquitination profiling identifies sensitivity factors for IAP antagonist treatment. (United States)

    Varfolomeev, Eugene; Izrael-Tomasevic, Anita; Yu, Kebing; Bustos, Daisy; Goncharov, Tatiana; Belmont, Lisa D; Masselot, Alexandre; Bakalarski, Corey E; Kirkpatrick, Donald S; Vucic, Domagoj


    Evasion of cell death is one crucial capability acquired by tumour cells to ward-off anti-tumour therapies and represents a fundamental challenge to sustaining clinical efficacy for currently available agents. Inhibitor of apoptosis (IAP) proteins use their ubiquitin E3 ligase activity to promote cancer cell survival by mediating proliferative signalling and blocking cell death in response to diverse stimuli. Using immunoaffinity enrichment and MS, ubiquitination sites on thousands of proteins were profiled upon initiation of cell death by IAP antagonists in IAP antagonist-sensitive and -resistant breast cancer cell lines. Our analyses identified hundreds of proteins with elevated levels of ubiquitin-remnant [K-GG (Lys-Gly-Gly)] peptides upon activation of cell death by the IAP antagonist BV6. The majority of these were observed in BV6-sensitive, but not-resistant, cells. Among these were known pro-apoptotic regulators, including CYC (cytochrome c), RIP1 (receptor-interacting protein 1) and a selection of proteins known to reside in the mitochondria or regulate NF-κB (nuclear factor κB) signalling. Analysis of early time-points revealed that IAP antagonist treatment stimulated rapid ubiquitination of NF-κB signalling proteins, including TRAF2 [TNF (tumour necrosis factor) receptor-associated factor 2], HOIL-1 (haem-oxidized iron-regulatory protein 2 ubiquitin ligase-1), NEMO (NF-κB essential modifier), as well as c-IAP1 (cellular IAP1) auto-ubiquitination. Knockdown of several NF-κB pathway members reduced BV6-induced cell death and TNF production in sensitive cell lines. Importantly, RIP1 was found to be constitutively ubiquitinated in sensitive breast-cancer cell lines at higher basal level than in resistant cell lines. Together, these data show the diverse and temporally defined roles of protein ubiquitination following IAP-antagonist treatment and provide critical insights into predictive diagnostics that may enhance clinical efficacy.

  4. Estrogenic effects of the new opioid antagonist naltrexone-estrone azine on pituitary luteinizing hormone secretion in ovariectomized rats. (United States)

    Armeanu, M C; van Dieten, J A; Kolb, V M; Schoemaker, J; de Koning, J


    The effect of the new opioid antagonist naltrexone-estrone azine (EH-NX) on pituitary luteinizing hormone (LH) secretion in the ovariectomized rat was studied. EH-NX is a hybrid between the steroid component estrone and the opioid antagonist naltrexone (NX). It is a potent and long-acting opioid antagonist in vitro and in vivo, but its effect upon in vivo LH secretion has not been tested before. The aims of the study were to investigate whether, unlike naltrexone, EH-NX can stimulate LH secretion without the need of additional estrogen pretreatment and whether EH-NX has peripheral estrogenic effects upon the uterine weight, when administered chronically to long-term ovariectomized rats. Female rats were injected subcutaneously with EH-NX 21 days after ovariectomy. The effects of EH-NX injections on LH secretion were compared to the effects of NX and estrone hydrazone (EH) alone, or in combination, with or without estradiol-benzoate (EB) pretreatment. Inhibition of LH secretion and uterine proliferation were observed in rats treated chronically with EH-NX in dosages of 0.250 mg/kg bw and higher. These effects were similar to those caused by EH and EB. In short-term OVX rats EH-NX appeared to act faster than EH. In contrast to NX, no stimulatory effect on LH secretion was seen with EH-NX in EB primed OVX rats. These results surprisingly demonstrate that EH-NX behaves like an estrogen and not like an opioid antagonist. The unexpected pharmacological profile of this new drug may open up doors for several medical applications.

  5. Glutamate and Opioid Antagonists Modulate Dopamine Levels Evoked by Innately Attractive Male Chemosignals in the Nucleus Accumbens of Female Rats (United States)

    Sánchez-Catalán, María-José; Orrico, Alejandro; Hipólito, Lucía; Zornoza, Teodoro; Polache, Ana; Lanuza, Enrique; Martínez-García, Fernando; Granero, Luis; Agustín-Pavón, Carmen


    Sexual chemosignals detected by vomeronasal and olfactory systems mediate intersexual attraction in rodents, and act as a natural reinforcer to them. The mesolimbic pathway processes natural rewards, and the nucleus accumbens receives olfactory information via glutamatergic projections from the amygdala. Thus, the aim of this study was to investigate the involvement of the mesolimbic pathway in the attraction toward sexual chemosignals. Our data show that female rats with no previous experience with males or their chemosignals display an innate preference for male-soiled bedding. Focal administration of the opioid antagonist β-funaltrexamine into the posterior ventral tegmental area does not affect preference for male chemosignals. Nevertheless, exposure to male-soiled bedding elicits an increase in dopamine efflux in the nucleus accumbens shell and core, measured by microdialysis. Infusion of the opioid antagonist naltrexone in the accumbens core does not significantly affect dopamine efflux during exposure to male chemosignals, although it enhances dopamine levels 40 min after withdrawal of the stimuli. By contrast, infusion of the glutamate antagonist kynurenic acid in the accumbens shell inhibits the release of dopamine and reduces the time that females spend investigating male-soiled bedding. These data are in agreement with previous reports in male rats showing that exposure to opposite-sex odors elicits dopamine release in the accumbens, and with data in female mice showing that the behavioral preference for male chemosignals is not affected by opioidergic antagonists. We hypothesize that glutamatergic projections from the amygdala into the accumbens might be important to modulate the neurochemical and behavioral responses elicited by sexual chemosignals in rats. PMID:28280461

  6. Cultivable bacteria populations associated with leaves of banana and plantain plants and their antagonistic activity against Mycosphaerella fijiensis. (United States)

    Ceballos, Isabel; Mosquera, Sandra; Angulo, Mónica; Mira, John J; Argel, Luz Edith; Uribe-Velez, Daniel; Romero-Tabarez, Magally; Orduz-Peralta, Sergio; Villegas, Valeska


    Mycosphaerella fijiensis is the etiological agent of Black Sigatoka, a fungal disease that affects production of banana and plantain crops in tropical regions. The sizes of cultivable epiphytic and endophytic bacterial populations, aerobic endospore forming bacteria (AEFB), and antagonist bacteria against M. fijiensis isolated from three Musa spp. cultivars from Urabá (Colombia) were studied, in order to find a suitable screening strategy to isolate antagonistic bacteria. Most of the variability found in the epiphytic and endophytic bacterial community sizes among fruit trees was explained by the cultivar differences. We found population sizes ranging from 1.25 × 10(3) to 9.64 × 10(5) CFU/g of fresh leaf and found that 44 % of total cultivable bacteria belong to the AEFB group. We isolated 648 AEFB from three different cultivars and assessed their antagonistic activity against M. fijiensis using the cell-free supernatant obtained from bacterial liquid cultures in three different in vitro assays. Five percent of those bacteria showed higher percent inhibition than the positive control Bacillus subtilis UA321 has (percent inhibition = 84 ± 5) in the screening phase. Therefore, they were selected as antagonistic bacteria against the pathogen. The strains with the highest percentage of antagonism were found in older leaves for the three cultivars, given support to recommend this group of leaves for future samplings. Some of these isolated bacteria affected the mycelium and ascospores morphology of the fungus. They also presented in vitro characteristics related to a successful colonization of the phylloplane such as indolic compounds, surfactant production, and biofilm formation, which makes them possible, potential candidates as biological control agents.

  7. Identification and Characterization of MEDI4736, an Antagonistic Anti-PD-L1 Monoclonal Antibody. (United States)

    Stewart, Ross; Morrow, Michelle; Hammond, Scott A; Mulgrew, Kathy; Marcus, Danielle; Poon, Edmund; Watkins, Amanda; Mullins, Stefanie; Chodorge, Matthieu; Andrews, John; Bannister, David; Dick, Emily; Crawford, Nicola; Parmentier, Julie; Alimzhanov, Marat; Babcook, John S; Foltz, Ian N; Buchanan, Andrew; Bedian, Vahe; Wilkinson, Robert W; McCourt, Matthew


    Programmed cell-death 1 ligand 1 (PD-L1) is a member of the B7/CD28 family of proteins that control T-cell activation. Many tumors can upregulate expression of PD-L1, inhibiting antitumor T-cell responses and avoiding immune surveillance and elimination. We have identified and characterized MEDI4736, a human IgG1 monoclonal antibody that binds with high affinity and specificity to PD-L1 and is uniquely engineered to prevent antibody-dependent cell-mediated cytotoxicity. In vitro assays demonstrate that MEDI4736 is a potent antagonist of PD-L1 function, blocking interaction with PD-1 and CD80 to overcome inhibition of primary human T-cell activation. In vivo MEDI4736 significantly inhibits the growth of human tumors in a novel xenograft model containing coimplanted human T cells. This activity is entirely dependent on the presence of transplanted T cells, supporting the immunological mechanism of action for MEDI4736. To further determine the utility of PD-L1 blockade, an anti-mouse PD-L1 antibody was investigated in immunocompetent mice. Here, anti-mouse PD-L1 significantly improved survival of mice implanted with CT26 colorectal cancer cells. The antitumor activity of anti-PD-L1 was enhanced by combination with oxaliplatin, which resulted in increased release of HMGB1 within CT26 tumors. Taken together, our results demonstrate that inhibition of PD-L1 function can have potent antitumor activity when used as monotherapy or in combination in preclinical models, and suggest it may be a promising therapeutic approach for the treatment of cancer. MEDI4736 is currently in several clinical trials both alone and in combination with other agents, including anti-CTLA-4, anti-PD-1, and inhibitors of IDO, MEK, BRAF, and EGFR.

  8. Design, synthesis, and structure-activity relationship of novel CCR2 antagonists. (United States)

    Kothandaraman, Shankaran; Donnely, Karla L; Butora, Gabor; Jiao, Richard; Pasternak, Alexander; Morriello, Gregori J; Goble, Stephen D; Zhou, Changyou; Mills, Sander G; Maccoss, Malcolm; Vicario, Pasquale P; Ayala, Julia M; Demartino, Julie A; Struthers, Mary; Cascieri, Margaret A; Yang, Lihu


    A series of novel 1-aminocyclopentyl-3-carboxyamides incorporating substituted tetrahydropyran moieties have been synthesized and subsequently evaluated for their antagonistic activity against the human CCR2 receptor. Among them analog 59 was found to posses potent antagonistic activity.

  9. Estrogen inhibits corticotropin-releasing hormone production in primary human placental cells

    Institute of Scientific and Technical Information of China (English)

    唐晓露; 倪鑫; 由振东; 何平; 惠宁; 顾清; 孙刚


    Objective: To study the inhibition effects of estrogen on the production of corticotropin-releasing hormone in human placental cells. Methods: Primary cultured placental cells were treated by ICI182, 780, a complete ER antagonist, and Tamoxifen, an ERα-mixed agonist/antagonist and ERβ antagonist for 24 h. The supernatant was havested for the radioimmunoassay of CRH. Results: 17β-estradiol inhibited the secretion of corticotropin-releasing hormone in human placental (P<0.05). ICI182, 780 stimulated the secretion of corticotropin-releasing hormone in human placental (P<0.05). Conclusion: Estrogen represses the synthesis and secretion of corticotropin-releasing hormone in human placental, which is possibly mediated by ERα.

  10. Transmitters and pathways mediating inhibition of spinal itch-signaling neurons by scratching and other counterstimuli.

    Directory of Open Access Journals (Sweden)

    Tasuku Akiyama

    Full Text Available Scratching relieves itch, but the underlying neural mechanisms are poorly understood. We presently investigated a role for the inhibitory neurotransmitters GABA and glycine in scratch-evoked inhibition of spinal itch-signaling neurons in a mouse model of chronic dry skin itch. Superficial dorsal horn neurons ipsilateral to hindpaw dry skin treatment exhibited a high level of spontaneous firing that was significantly attenuated by cutaneous scratching, pinch and noxious heat. Scratch-evoked inhibition was nearly abolished by spinal delivery of the glycine antagonist, strychnine, and was markedly attenuated by respective GABA(A and GABA(B antagonists bicuculline and saclofen. Scratch-evoked inhibition was also significantly attenuated (but not abolished by interruption of the upper cervical spinal cord, indicating the involvement of both segmental and suprasegmental circuits that engage glycine- and GABA-mediated inhibition of spinal itch-signaling neurons by noxious counterstimuli.

  11. Cannabinoid receptor-2 selective antagonist negatively regulates receptor activator of nuclear factor kappa B ligand mediated osteoclastogenesis

    Institute of Scientific and Technical Information of China (English)

    GENG De-chun; XU Yao-zeng; YANG Hui-lin; ZHU Guang-ming; WANG Xian-bin; ZHU Xue-song


    Background The cannabinoid receptor-2 (CB2) is important for bone remodeling. In this study, we investigated the effects of CB2 selective antagonist (AM630) on receptor activator of nuclear factor kappa B (RANK) ligand (RANKL)induced osteoclast differentiation and the underlying signaling pathway using a monocyte-macrophage cell line-RAW264.7.Methods RAW264.7 was cultured with RANKL for 6 days and then treated with AM630 for 24 hours. Mature osteoclasts were measured by tartrate-resistant acid phosphatase (TRAP) staining using a commercial kit. Total ribonucleic acid (RNA)was isolated and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was done to examine the expression of RANK, cathepsin K (CPK) and nuclear factor kappa B (NF-κB). The extracellular signal-regulated kinase (ERK),phosphorylation of ERK (P-ERK) and NF-κB production were tested by Western blotting. The effect of AM630 on RAW264.7 viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay.Results AM630 did not affect the viability of RAW264.7. However, this CB2 selective antagonist markedly inhibited osteoclast formation and the inhibition rate was dose-dependent. The dose of >100 nmol/L could reduce TRAP positive cells to the levels that were significantly lower than the control. AM630 suppressed the expression of genes associated with osteoclast differentiation and activation, such as RANK and CPK. An analysis of a signaling pathway showed that AM630 inhibited the RANKL-induced activation of ERK, but not NF-κB.Conclusion AM630 could inhibit the osteoclastogenesis from RAW264.7 induced with RANKL.

  12. Effect of two human growth hormone receptor antagonists on glomerulosclerosis in streptozotocin-induced diabetic rats

    Institute of Scientific and Technical Information of China (English)

    Wei LI; Shui-xian SHEN; Li-hua ZHU; En-bi WANG; Zeng-can YE; Jun LIN; Li-he GUO; Fei-hong LUO; Xi-hong LIU; Xin FANG


    AIM: To explore the feasibility of human growth hormone (hGH) receptor antagonist in the treatment of end-stage diabetic renal complications. METHODS: Two hGH mutants, hGHA1 (Cys-hGH-dell-4, G120R, K168A, E174A,C182S, de1186-191) and hGHA2 (hGH-H21A, G120R, E174A) were expressed in E coli. The IC50 (Mean±SD)values for the mutants for inhibiting 125I-hGH binding to rabbit growth hormone receptor were (65±10) ng for hGHA1, (27±5.6) ng for hGHA2, and (10±0.6) ng for wild type hGH, respectively. RESULTS: After treatment for 12 weeks, the renal histology analysis showed that treatment with hGHA2 at 4 mg/kg body weight daily markedly suppressed glomerulosclerosis in streptozotocin-induced diabetic Sprague-Dawley (SD) rats; hGHA1 at the same dosage slightly increased the renal damage compared with saline; while wild type hGH at 1 U/kg body weight daily severely worsened the glomerulo-sclerosis in diabetic SD rats. CONCLUSION: The data indicated that hGHA2 inhibited the end-stage glomerulosclerosis in diabetic rats, but hGHA1 mildly increased the glomerulosclerosis.

  13. Isolation of maize soil and rhizosphere bacteria with antagonistic activity against Aspergillus flavus and Fusarium verticillioides. (United States)

    Palumbo, Jeffrey D; O'Keeffe, Teresa L; Abbas, Hamed K


    Bacterial isolates from Mississippi maize field soil and maize rhizosphere samples were evaluated for their potential as biological control agents against Aspergillus flavus and Fusarium verticillioides. Isolated strains were screened for antagonistic activities in liquid coculture against A. flavus and on agar media against A. flavus and F. verticillioides. We identified 221 strains that inhibited growth of both fungi. These bacteria were further differentiated by their production of extracellular enzymes that hydrolyzed chitin and yeast cell walls and by production of antifungal metabolites. Based on molecular and nutritional identification of the bacterial strains, the most prevalent genera isolated from rhizosphere samples were Burkholderia and Pseudomonas, and the most prevalent genera isolated from nonrhizosphere soil were Pseudomonas and Bacillus. Less prevalent genera included Stenotrophomonas, Agrobacterium, Variovorax, Wautersia, and several genera of coryneform and enteric bacteria. In quantitative coculture assays, strains of P. chlororaphis and P. fluorescens consistently inhibited growth of A. flavus and F. verticillioides in different media. These results demonstrate the potential for developing individual biocontrol agents for simultaneous control of the mycotoxigenic A. flavus and F. verticillioides.

  14. Pharmacological profiling an abundantly expressed schistosome serotonergic GPCR identifies nuciferine as a potent antagonist

    Directory of Open Access Journals (Sweden)

    John D. Chan


    Full Text Available 5-hydroxytryptamine (5-HT is a key regulator of muscle contraction in parasitic flatworms. In Schistosoma mansoni, the myoexcitatory action of 5-HT is effected through activation of a serotonergic GPCR (Sm.5HTRL, prioritizing pharmacological characterization of this target for anthelmintic drug discovery. Here, we have examined the effects of several aporphine alkaloids on the signaling activity of a heterologously expressed Sm.5HTRL construct using a cAMP biosensor assay. Four structurally related natural products – nuciferine, D-glaucine, boldine and bulbocapnine – were demonstrated to block Sm.5HTRL evoked cAMP generation with the potency of GPCR blockade correlating well with the ability of each drug to inhibit contractility of schistosomule larvae. Nuciferine was also effective at inhibiting both basal and 5-HT evoked motility of adult schistosomes. These data advance our understanding of structure-affinity relationships at Sm.5HTRL, and demonstrate the effectiveness of Sm.5HTRL antagonists as hypomotility-evoking drugs across different parasite life cycle stages.

  15. Biocontrol of Fusarium graminearum Growth and Deoxynivalenol Production in Wheat Kernels with Bacterial Antagonists

    Directory of Open Access Journals (Sweden)

    Cuijuan Shi


    Full Text Available Fusarium graminearum is the main causal pathogen affecting small-grain cereals, and it produces deoxynivalenol, a kind of mycotoxin, which displays a wide range of toxic effects in human and animals. Bacterial strains isolated from peanut shells were investigated for their activities against F. graminearum by dual-culture plate and tip-culture assays. Among them, twenty strains exhibited potent inhibition to the growth of F. graminearum, and the inhibition rates ranged from 41.41% to 54.55% in dual-culture plate assay and 92.70% to 100% in tip-culture assay. Furthermore, eighteen strains reduced the production of deoxynivalenol by 16.69% to 90.30% in the wheat kernels assay. Finally, the strains with the strongest inhibitory activity were identified by morphological, physiological, biochemical methods and also 16S rDNA and gyrA gene analysis as Bacillus amyloliquefaciens. The current study highlights the potential application of antagonistic microorganisms and their metabolites in the prevention of fungal growth and mycotoxin production in wheat kernels. As a biological strategy, it might avoid safety problems and nutrition loss which always caused by physical and chemical strategies.

  16. Antagonistic control of social versus repetitive self-grooming behaviors by separable amygdala neuronal subsets. (United States)

    Hong, Weizhe; Kim, Dong-Wook; Anderson, David J


    Animals display a range of innate social behaviors that play essential roles in survival and reproduction. While the medial amygdala (MeA) has been implicated in prototypic social behaviors such as aggression, the circuit-level mechanisms controlling such behaviors are not well understood. Using cell-type-specific functional manipulations, we find that distinct neuronal populations in the MeA control different social and asocial behaviors. A GABAergic subpopulation promotes aggression and two other social behaviors, while neighboring glutamatergic neurons promote repetitive self-grooming, an asocial behavior. Moreover, this glutamatergic subpopulation inhibits social interactions independently of its effect to promote self-grooming, while the GABAergic subpopulation inhibits self-grooming, even in a nonsocial context. These data suggest that social versus repetitive asocial behaviors are controlled in an antagonistic manner by inhibitory versus excitatory amygdala subpopulations, respectively. These findings provide a framework for understanding circuit-level mechanisms underlying opponency between innate behaviors, with implications for their perturbation in psychiatric disorders.

  17. Nicalin and its binding partner Nomo are novel Nodal signaling antagonists. (United States)

    Haffner, Christof; Frauli, Mélanie; Topp, Stephanie; Irmler, Martin; Hofmann, Kay; Regula, Jörg T; Bally-Cuif, Laure; Haass, Christian


    Nodals are signaling factors of the transforming growth factor-beta (TGFbeta) superfamily with a key role in vertebrate development. They control a variety of cell fate decisions required for the establishment of the embryonic body plan. We have identified two highly conserved transmembrane proteins, Nicalin and Nomo (Nodal modulator, previously known as pM5), as novel antagonists of Nodal signaling. Nicalin is distantly related to Nicastrin, a component of the Alzheimer's disease-associated gamma-secretase, and forms a complex with Nomo. Ectopic expression of both proteins in zebrafish embryos causes cyclopia, a phenotype that can arise from a defect in mesendoderm patterning mediated by the Nodal signaling pathway. Accordingly, downregulation of Nomo resulted in an increase in anterior axial mesendoderm and the development of an enlarged hatching gland. Inhibition of Nodal signaling by ectopic expression of Lefty was rescued by reducing Nomo levels. Furthermore, Nodal- as well as Activin-induced signaling was inhibited by Nicalin and Nomo in a cell-based reporter assay. Our data demonstrate that the Nicalin/Nomo complex antagonizes Nodal signaling during mesendodermal patterning in zebrafish.

  18. Kinetic profiling an abundantly expressed planarian serotonergic GPCR identifies bromocriptine as a perdurant antagonist

    Directory of Open Access Journals (Sweden)

    John D. Chan


    Full Text Available The diversity and uniqueness of flatworm G protein coupled receptors (GPCRs provides impetus for identifying ligands useful as tools for studying flatworm biology, or as therapeutics for treating diseases caused by parasitic flatworm infections. To catalyse this discovery process, technologies optimized for mammalian GPCR high throughput screening need be transposed for screening flatworm GPCRs. Here, we demonstrate the utility of a genetically encoded cAMP biosensor for resolving the properties of an abundantly expressed planarian serotonergic GPCR (S7.1R. Application of this methodology resolved the real time kinetics of GPCR modulation by ligands and demonstrated a marked difference in the kinetic action of antagonists at S7.1R. Notably, bromocriptine caused a protracted inhibition of S7.1R activity in vitro and a protracted paralysis of planarian movement, replicating the effect of S7.1R in vivo RNAi. The lengthy inhibition of function caused by bromocriptine at this abundantly expressed GPCR provides a useful tool to ablate serotonergic signaling in vivo, and is a noteworthy feature for exploitation as an anthelmintic vulnerability.

  19. Design and discovery of 1,3-benzodiazepines as novel dopamine antagonists. (United States)

    Zhu, Zhaoning; Sun, Zhong-Yue; Ye, Yuanzan; McKittrick, Brian; Greenlee, William; Czarniecki, Michael; Fawzi, Ahmad; Zhang, Hongtao; Lachowicz, Jean E


    A series of novel 1,3-benzodiazapine based D1 antagonists was designed according to the understanding of pharmacophore models derived from SCH 23390 (1b), a potent and selective D1 antagonist. The new design features an achiral cyclic-amidine that maintains desired basicity. Solid phase synthesis was developed for SAR development of the novel dopamine antagonists.

  20. Biased small-molecule ligands for selective inhibition of HIV-1 cell entry via CCR5

    DEFF Research Database (Denmark)

    Berg, Christian; Spiess, Katja; von Lüttichau, Hans Rudolf;


    Since the discovery of HIV's use of CCR5 as the primary coreceptor in fusion, the focus on developing small-molecule receptor antagonists for inhibition hereof has only resulted in one single drug, Maraviroc. We therefore investigated the possibility of using small-molecule CCR5 agonists as HIV-1...

  1. How microelectrode array-based chick forebrain neuron biosensors respond to glutamate NMDA receptor antagonist AP5 and GABAA receptor antagonist musimol

    Directory of Open Access Journals (Sweden)

    Serena Y. Kuang


    Full Text Available We have established a long-term, stable primary chick forebrain neuron (FBN culture on a microelectrode array platform as a biosensor system for neurotoxicant screening and for neuroelectrophysiological studies for multiple purposes. This paper reports some of our results, which characterize the biosensor pharmacologically. Dose-response experiments were conducted using NMDA receptor antagonist AP5 and GABAA receptor agonist musimol (MUS. The chick FBN biosensor (C-FBN-biosensor responds to the two agents in a pattern similar to that of rodent counterparts; the estimated EC50s (the effective concentration that causes 50% inhibition of the maximal effect are 2.3 μM and 0.25 μM, respectively. Intercultural and intracultural reproducibility and long-term reusability of the C-FBN-biosensor are addressed and discussed. A phenomenon of sensitization of the biosensor that accompanies intracultural reproducibility in paired dose-response experiments for the same agent (AP5 or MUS is reported. The potential application of the C-FBN-biosensor as an alternative to rodent biosensors in shared sensing domains (NMDA receptor and GABAA receptor is suggested.

  2. Lead optimization studies of cinnamic amide EP2 antagonists. (United States)

    Ganesh, Thota; Jiang, Jianxiong; Yang, Myung-Soon; Dingledine, Ray


    Prostanoid receptor EP2 can play a proinflammatory role, exacerbating disease pathology in a variety of central nervous system and peripheral diseases. A highly selective EP2 antagonist could be useful as a drug to mitigate the inflammatory consequences of EP2 activation. We recently identified a cinnamic amide class of EP2 antagonists. The lead compound in this class (5d) displays anti-inflammatory and neuroprotective actions. However, this compound exhibited moderate selectivity to EP2 over the DP1 prostanoid receptor (∼10-fold) and low aqueous solubility. We now report compounds that display up to 180-fold selectivity against DP1 and up to 9-fold higher aqueous solubility than our previous lead. The newly developed compounds also display higher selectivity against EP4 and IP receptors and a comparable plasma pharmacokinetics. Thus, these compounds are useful for proof of concept studies in a variety of models where EP2 activation is playing a deleterious role.

  3. Anti-antimicrobial peptides: folding-mediated host defense antagonists. (United States)

    Ryan, Lloyd; Lamarre, Baptiste; Diu, Ting; Ravi, Jascindra; Judge, Peter J; Temple, Adam; Carr, Matthew; Cerasoli, Eleonora; Su, Bo; Jenkinson, Howard F; Martyna, Glenn; Crain, Jason; Watts, Anthony; Ryadnov, Maxim G


    Antimicrobial or host defense peptides are innate immune regulators found in all multicellular organisms. Many of them fold into membrane-bound α-helices and function by causing cell wall disruption in microorganisms. Herein we probe the possibility and functional implications of antimicrobial antagonism mediated by complementary coiled-coil interactions between antimicrobial peptides and de novo designed antagonists: anti-antimicrobial peptides. Using sequences from native helical families such as cathelicidins, cecropins, and magainins we demonstrate that designed antagonists can co-fold with antimicrobial peptides into functionally inert helical oligomers. The properties and function of the resulting assemblies were studied in solution, membrane environments, and in bacterial culture by a combination of chiroptical and solid-state NMR spectroscopies, microscopy, bioassays, and molecular dynamics simulations. The findings offer a molecular rationale for anti-antimicrobial responses with potential implications for antimicrobial resistance.

  4. Churg-Strauss syndrome associated with leukotriene receptor antagonists (LTRA). (United States)

    Cuchacovich, R; Justiniano, M; Espinoza, L R


    Churg-Strauss syndrome (CSS) is a rare vasculitic disorder that generally occurs in patients with bronchial asthma. CSS is being increasingly recognized in asthmatic patients treated with leukotriene receptor antagonists. However, the nature of this relationship remains to be elucidated. The present report describes three asthmatic patients who developed clinical manifestations highly suggestive of CSS, although one patient lacked the presence of eosinophilia. The patient, however, exhibited biopsy-proven cutaneous necrotizing vasculitis, which improved after withdrawal of montelukast. The second patient presented with systemic constitutional signs including fever, malaise, arthralgias, clinical jaundice, peripheral blood eosinophilia, and biopsy-proven eosinophilic hepatitis. The third patient also had circulating eosinophilia, scleritis, and arthritis. All patients improved after discontinuation of the leukotriene receptor antagonist (montelukast).

  5. Potential Clinical Implications of the Urotensin II Receptor Antagonists

    Directory of Open Access Journals (Sweden)

    Emilie Kane


    Full Text Available Urotensin-II (UII, which binds to its receptor UT, plays an important role in the heart, kidneys, pancreas, adrenal gland and CNS. In the vasculature, it acts as a potent endothelium-independent vasoconstrictor and endothelium-dependent vasodilator. In disease states, this constriction-dilation equilibrium is disrupted. There is an upregulation of the UII system in heart disease, metabolic syndrome and kidney failure. The increase in UII release and UT expression suggest that UII system may be implicated in the pathology and pathogenesis of these diseases by causing an increase in ACAT-1 activity leading to SMC proliferation and foam cell infiltration, insulin resistance (DMII, as well as inflammation, high blood pressure and plaque formation. Recently, UT antagonists such as SB-611812, palosuran, and most recently a piperazino-isoindolinone based antagonist have been developed in the hope of better understanding the UII system and treating its associated diseases.

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

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen


    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 proliferation and angiogenesis. Specific histamine receptors have been identified on the surface of bone marrow cells, immune competent cells, endothelial cells, fibroblasts, and also on malignant cells. This has prompted research in regulation by specific histamine receptor agonists and antagonists. Results...... from such studies are currently accumulating and suggest that the histamine-2 receptor antagonists have potential beneficial effects in the treatment of certain malignant, autoimmune and skin diseases, either alone or in combination with other drugs. The beneficial effect of histamine-2 receptor...

  7. Are peripheral opioid antagonists the solution to opioid side effects?

    LENUS (Irish Health Repository)

    Bates, John J


    Opioid medication is the mainstay of therapy for severe acute and chronic pain. Unfortunately, the side effects of these medications can affect patient comfort and safety, thus limiting their proven therapeutic potential. Whereas the main analgesic effects of opioids are centrally mediated, many of the common side effects are mediated via peripheral receptors. Novel peripheral opioid antagonists have been recently introduced that can block the peripheral actions of opioids without affecting centrally mediated analgesia. We review the clinical and experimental evidence of their efficacy in ameliorating opioid side effects and consider what further information might be useful in defining their role. IMPLICATIONS: The major analgesic effects of opioid medication are mediated within the brain and spinal cord. Many of the side effects of opioids are caused by activation of receptors outside these areas. Recently developed peripherally restricted opioid antagonists have the ability to block many opioid side effects without affecting analgesia.

  8. Non-imidazole histamine NO-donor H3-antagonists. (United States)

    Tosco, Paolo; Bertinaria, Massimo; Di Stilo, Antonella; Cena, Clara; Fruttero, Roberta; Gasco, Alberto


    Recently a series of H3-antagonists related to Imoproxifan was realised (I); in these products the oxime substructure of the lead was constrained in NO-donor furoxan systems and in the corresponding furazan derivatives. In this paper, a new series of compounds derived from I by substituting the imidazole ring with the ethoxycarbonylpiperazino moiety present in the non-imidazole H3-ligand A-923 is described. For all the products synthesis and preliminary pharmacological characterisation, as well as their hydrophilic-lipophilic balance, are reported. The imidazole ring replacement generally results in a decreased H3-antagonist activity with respect to the analogues of series I and, in some cases, induces relaxing effects on the electrically contracted guinea-pig ileum, probably due to increased affinity for other receptor systems.

  9. Exploring details about structure requirements based on novel CGRP receptor antagonists urethanamide, aspartate, succinate and pyridine derivatives by in silico methods (United States)

    Li, Yan; He, Haoran; Wang, Jinghui; Han, Chunxiao; Feng, Jiaqi; Zhang, Shuwei; Yang, Ling


    The migraine never fails to afflict individuals in the world that knows no lack of such cases. CGRP (calcitonin gene-related peptide) is found closely related to migraine and olcegepant (BIBN4096) is effective in alleviating the pain. In our work, the combination of ligand- and receptor-based three-dimensional quantitative structure-activity relationship (3D-QSAR) studies along with molecular docking was applied to provide us insights about how urethanamide, pyridine and aspartate and succinate derivatives (novel CGRP receptor antagonists) play a part in inhibiting the activity of CGRP receptor. The optimal CoMSIA model shows the Q2 of 0.505, R2ncv of 0.992 and its accurate predictive ability was confirmed by checking out an independent test set which gave R2pred value of 0.885. Besides, the 3D contour maps help us identify how different groups affect the antagonist activity while connecting to some key positions. In addition, the docking analysis shows the binding site emerging as the distorted “V” shape and including two binding pockets: one of them is hydrophobic, fixing the structural part 3 of compound 80, the other anchors the part 1 of compound 80. The docking analysis also shows the interaction mechanism between compound 80 and CGRP receptor, similar to the interaction between olcegepant and CGRP receptor. The findings derived from this work reveal the mechanism of related antagonists and facilitate the future rational design of novel antagonists with higher potency.

  10. Selection of Antagonistic Fungi to Species of Pathogens on Camellia oleifera%油茶病原菌拮抗菌筛选

    Institute of Scientific and Technical Information of China (English)

    卢东升; 产帅; 代兵


    通过拮抗实验,研究了59个野菊内生真菌菌株对油茶炭疽病及油茶稍枯病病原菌的拮抗性.结果表明:89.8%供试真菌菌株对油茶病原菌孢子萌发或菌丝生长有抑制作用.拮抗菌株在代谢过程中能产生抑制病原菌生长发育的抑菌物质,这些物质存在于菌丝内或分泌于菌丝外.筛选得到2个油荼病原菌强拮抗菌株,大茎点霉菌Y11和Y29.%Through antagonistic test,the antagonistic characteristics of 59 endophytic fungus strains from Chrysanthemum indicum to two species of pathogens on Camellia oleifera were studied. The results showed that 89. 8% strains of the endophytic fungi tested can inhibit the spore bourgeon and hypha growth of the pathogen on Camellia oleifera. The antagonistic fungus strains could produce some substances,existed in hypha cells or excreted out of mycelium, to restrain fungi. Two strains of endophytic fungi,Yll and Y29,having strong antagonistic characteristic were gained by selection.

  11. Bone morphogenetic protein antagonist gremlin 1 is widely expressed by cancer-associated stromal cells and can promote tumor cell proliferation (United States)

    Sneddon, Julie B.; Zhen, Hanson H.; Montgomery, Kelli; van de Rijn, Matt; Tward, Aaron D.; West, Robert; Gladstone, Hayes; Chang, Howard Y.; Morganroth, Greg S.; Oro, Anthony E.; Brown, Patrick O.


    Although tissue microenvironments play critical roles in epithelial development and tumorigenesis, the factors mediating these effects are poorly understood. In this work, we used a genomic approach to identify factors produced by cells in the microenvironment of basal cell carcinoma (BCC) of the skin, one of the most common human cancers. The global gene expression programs of stromal cell cultures derived from human BCCs showed consistent, systematic differences from those derived from nontumor skin. The gene most consistently expressed at a higher level in BCC tumor stromal cells compared with those from nontumor skin was GREMLIN 1, which encodes a secreted antagonist of the bone morphogenetic protein (BMP) pathway. BMPs and their antagonists are known to play a crucial role in stem and progenitor cell biology as regulators of the balance between expansion and differentiation. Consistent with the hypothesis that BMP antagonists might have a similar role in cancer, we found GREMLIN 1 expression in the stroma of human BCC tumors but not in normal skin in vivo. Furthermore, BMP 2 and 4 are expressed by BCC cells. Ex vivo, BMP inhibits, and Gremlin 1 promotes, proliferation of cultured BCC cells. We further found that GREMLIN 1 is expressed by stromal cells in many carcinomas but not in the corresponding normal tissue counterparts that we examined. Our data suggest that BMP antagonists may be important constituents of tumor stroma, providing a favorable microenvironment for cancer cell survival and expansion in many cancers. cancer biology | stem cell regulation | tissue microenvironment | tumor stroma

  12. Antagonistic activity of dairy lactobacilli against gram-foodborne pathogens - doi: 10.4025/actascitechnol.v36i1.18776

    Directory of Open Access Journals (Sweden)

    Marco Geria


    Full Text Available Thirty-five strains of lactic acid bacteria were isolated from artisanal raw milk cheese, presumptively identified and tested against one dairy Escherichia coli strain. Six lactobacilli, exhibiting antagonistic activity, were identified at the species level and their action was evaluated against four strains of Gram-foodborne pathogens (Escherichia coli O26, Escherichia coli O157:H7, Salmonella spp. 1023, and Salmonella Typhimurium and the control strain Escherichia coli ATCC 45922. The antagonistic activity was determined by spot method and the inhibition zones were measured by Autodesk AutoCAD 2007. Three strains, all Lactobacillus paracasei, were active against all the pathogens; the other strains, all Lactobacillus plantarum, showed antagonistic activity against some pathogens. This study highlights the intense and different antagonistic activity induced by lactobacilli against various foodborne pathogens thus demonstrating that using selected lactic acid bacteria strains as adjunct cultures could be an effective strategy to prevent the development of foodborne pathogens in artisanal raw milk cheeses, and thus improving their safety.

  13. Enhanced Chronic Pain Management Utilizing Chemokine Receptor Antagonists (United States)


    Center for Substance Abuse Research Lewis Katz School of Medicine at Temple University 3500 N, Broad Street Philadelphia, PA 19140 AND ADDRESS(ES) 8...processes), affect the ability of opioid drugs to counteract pain. We predicted that one way of increasing the effectiveness of the pain-relieving... drugs would be to eliminate or reduce the activity of the chemokines by administering chemokine receptor antagonists (CRAs). The blockade of one or

  14. Potent and orally efficacious benzothiazole amides as TRPV1 antagonists. (United States)

    Besidski, Yevgeni; Brown, William; Bylund, Johan; Dabrowski, Michael; Dautrey, Sophie; Harter, Magali; Horoszok, Lucy; Hu, Yin; Johnson, Dean; Johnstone, Shawn; Jones, Paul; Leclerc, Sandrine; Kolmodin, Karin; Kers, Inger; Labarre, Maryse; Labrecque, Denis; Laird, Jennifer; Lundström, Therese; Martino, John; Maudet, Mickaël; Munro, Alexander; Nylöf, Martin; Penwell, Andrea; Rotticci, Didier; Slaitas, Andis; Sundgren-Andersson, Anna; Svensson, Mats; Terp, Gitte; Villanueva, Huascar; Walpole, Christopher; Zemribo, Ronald; Griffin, Andrew M


    Benzothiazole amides were identified as TRPV1 antagonists from high throughput screening using recombinant human TRPV1 receptor and structure-activity relationships were explored to pinpoint key pharmacophore interactions. By increasing aqueous solubility, through the attachment of polar groups to the benzothiazole core, and enhancing metabolic stability, by blocking metabolic sites, the drug-like properties and pharmokinetic profiles of benzothiazole compounds were sufficiently optimized such that their therapeutic potential could be verified in rat pharmacological models of pain.

  15. Epiminocyclohepta[b]indole analogs as 5-HT6 antagonists

    DEFF Research Database (Denmark)

    Henderson, Alan J; Guzzo, Peter R; Ghosh, Animesh;


    A new series of epiminocyclohepta[b]indoles with potent 5-HT(6) antagonist activity were discovered and optimized using in vitro protocols. One compound from this series was progressed to advanced pharmacokinetic (PK) studies followed by 5-HT(6) receptor occupancy studies. The compound was found...... to have excellent oral absorption, a highly favorable PK profile and demonstrated pharmacodynamic interaction with the 5-HT(6) receptor as shown by ex vivo autoradiography....

  16. Mineralocorticoid receptor antagonists: emerging roles in cardiovascular medicine


    Funder JW


    John W FunderPrince Henry's Institute, Clayton, Victoria, AustraliaAbstract: Spironolactone was first developed over 50 years ago as a potent mineralocorticoid receptor (MR) antagonist with undesirable side effects; it was followed a decade ago by eplerenone, which is less potent but much more MR-specific. From a marginal role as a potassium-sparing diuretic, spironolactone was shown to be an extraordinarily effective adjunctive agent in the treatment of progressive heart failure, as ...

  17. Functioning of peripheral Ia pathways in infants with typical development: responses in antagonist muscle pairs. (United States)

    Teulier, Caroline; Ulrich, Beverly D; Martin, Bernard


    In muscle responses of proprioceptive origin, including the stretch/tendon reflex (T-reflex), the corresponding reciprocal excitation and irradiation to distant muscles have been described from newborn infants to older adults. However, the functioning of other responses mediated primarily by Ia-afferents has not been investigated in infants. Understanding the typical development of these multiple pathways is critical to determining potential problems in their development in populations affected by neurological disease, such as spina bifida or cerebral palsy. Hence, the goal of the present study was to quantify the excitability of Ia-mediated responses in lower limb muscles of infants with typical development. These responses were elicited by mechanical stimulation applied to the distal tendons of the gastrocnemius-soleus (GS), tibialis anterior (TA) and quadriceps (QAD) muscles of both legs in twelve 2- to 10-month-old infants and recorded simultaneously in antagonist muscle pairs by surface EMG. Tendon taps alone elicited responses in either, both or neither muscle. The homonymous response (T-reflex) was less frequent in the TA than the GS or QAD muscle. An 80 Hz vibration superimposed on tendon taps induced primarily an inhibition of monosynaptic responses; however, facilitation also occurred in either muscle of the recorded pair. These responses were not influenced significantly by age or gender. Vibration alone produced a tonic reflex response in the vibrated muscle (TVR) and/or the antagonist muscle (AVR). However, for the TA muscle the TVR was more frequently elicited in older than younger infants. High variability was common to all responses. Overall, the random distribution and inconsistency of muscle responses suggests that the gain of Ia-mediated feedback is unstable. We propose that during infancy the central nervous system needs to learn to set stable feedback gain, or destination of proprioceptive assistance, based on their use during functional

  18. Antagonistic effects of atipamezole and yohimbine on xylazine-induced diuresis in healthy dogs. (United States)

    Talukder, Hasanuzzaman; Hikasa, Yoshiaki; Matsuu, Aya; Kawamura, Hiroe


    The aim of this study was to investigate and compare the antagonistic effects of atipamezole and yohimbine on xylazine-induced diuresis in healthy dogs. Five healthy male beagles were assigned to each of the 8 treatment groups in a randomized design at 1-week intervals in the same dog. One group was not medicated. The dogs in the other groups received 2 mg/kg xylazine intramuscularly (IM) and a treatment of saline (control), 50, 100 or 300 microg/kg of each atipamezole or yohimbine IM 0.5 hr later. Urine and blood samples were collected 11 times over the course of 24 hr. Urine volume, pH, specific gravity and creatinine values; osmolality, electrolyte and arginine vasopressin (AVP) values in both urine and plasma; and plasma atrial natriuretic peptide (ANP) concentration were measured. Both atipamezole and yohimbine antagonized xylazine-induced diuresis. The reversal effect of yohimbine was more potent, but not dose-dependent at the tested doses, in contrast with atipamezole. Both atipamezole and yohimbine exhibited similar potency in reversing the decreases in urine specific gravity, osmolality, creatinine, sodium and chloride concentrations and the increase in the plasma potassium concentration induced by xylazine. Both also inhibited xylazine-induced diuresis without significantly altering the hormonal profile in the dogs. A higher dose of atipamezole tended to increase the plasma ANP concentration. This may not be due only to actions mediated by alpha(2)-adrenoceptors. Both drugs can be used as antagonistic agents against xylazine-induced diuresis in healthy dogs.

  19. Definition of critical periods for Hedgehog pathway antagonist-induced holoprosencephaly, cleft lip, and cleft palate.

    Directory of Open Access Journals (Sweden)

    Galen W Heyne

    Full Text Available The Hedgehog (Hh signaling pathway mediates multiple spatiotemporally-specific aspects of brain and face development. Genetic and chemical disruptions of the pathway are known to result in an array of structural malformations, including holoprosencephaly (HPE, clefts of the lip with or without cleft palate (CL/P, and clefts of the secondary palate only (CPO. Here, we examined patterns of dysmorphology caused by acute, stage-specific Hh signaling inhibition. Timed-pregnant wildtype C57BL/6J mice were administered a single dose of the potent pathway antagonist vismodegib at discrete time points between gestational day (GD 7.0 and 10.0, an interval approximately corresponding to the 15th to 24th days of human gestation. The resultant pattern of facial and brain dysmorphology was dependent upon stage of exposure. Insult between GD7.0 and GD8.25 resulted in HPE, with peak incidence following exposure at GD7.5. Unilateral clefts of the lip extending into the primary palate were also observed, with peak incidence following exposure at GD8.875. Insult between GD9.0 and GD10.0 resulted in CPO and forelimb abnormalities. We have previously demonstrated that Hh antagonist-induced cleft lip results from deficiency of the medial nasal process and show here that CPO is associated with reduced growth of the maxillary-derived palatal shelves. By defining the critical periods for the induction of HPE, CL/P, and CPO with fine temporal resolution, these results provide a mechanism by which Hh pathway disruption can result in "non-syndromic" orofacial clefting, or HPE with or without co-occurring clefts. This study also establishes a novel and tractable mouse model of human craniofacial malformations using a single dose of a commercially available and pathway-specific drug.

  20. Identification and characterization of a selective allosteric antagonist of human P2X4 receptor channels. (United States)

    Ase, Ariel R; Honson, Nicolette S; Zaghdane, Helmi; Pfeifer, Tom A; Séguéla, Philippe


    P2X4 is an ATP-gated nonselective cation channel highly permeable to calcium. There is increasing evidence that this homomeric purinoceptor, which is expressed in several neuronal and immune cell types, is involved in chronic pain and inflammation. The current paucity of unambiguous pharmacological tools available to interrogate or modulate P2X4 function led us to pursue the search for selective antagonists. In the high-throughput screen of a compound library, we identified the phenylurea BX430 (1-(2,6-dibromo-4-isopropyl-phenyl)-3-(3-pyridyl)urea, molecular weight = 413), with antagonist properties on human P2X4-mediated calcium uptake. Patch-clamp electrophysiology confirmed direct inhibition of P2X4 currents by extracellular BX430, with submicromolar potency (IC50 = 0.54 µM). BX430 is highly selective, having virtually no functional impact on all other P2X subtypes, namely, P2X1-P2X3, P2X5, and P2X7, at 10-100 times its IC50. Unexpected species differences were noticed, as BX430 is a potent antagonist of zebrafish P2X4 but has no effect on rat and mouse P2X4 orthologs. The concentration-response curve for ATP on human P2X4 in the presence of BX430 shows an insurmountable blockade, indicating a noncompetitive allosteric mechanism of action. Using a fluorescent dye uptake assay, we observed that BX430 also effectively suppresses ATP-evoked and ivermectin-potentiated membrane permeabilization induced by P2X4 pore dilation. Finally, in single-cell calcium imaging, we validated its selective inhibitory effects on native P2X4 channels at the surface of human THP-1 cells that were differentiated into macrophages. In summary, this ligand provides a novel molecular probe to assess the specific role of P2X4 in inflammatory and neuropathic conditions, where ATP signaling has been shown to be dysfunctional.

  1. Approaches to the rational design of selective melanocortin receptor antagonists (United States)

    Hruby, Victor J; Cai, Minying; Nyberg, Joel; Muthu, Dhanasekaran


    Introduction When establishing the physiological roles of specific receptors in normal and disease states, it is critical to have selective antagonist ligands for each receptor in a receptor system with several subtypes. The melanocortin receptors have five subtypes referred to as the melanocortin 1 receptor, melanocortin 2 receptor, melanocortin 3 receptor, melanocortin 4 receptor and melanocortin 5 receptor, and they are of critical importance for many aspects of human health and disease. Areas covered This article reviews the current efforts to design selective antagonistic ligands for the five human melanocortin receptors summarizing the currently published orthosteric and allosteric antagonists for each of these receptors. Expert opinion Though there has been progress, there are still few drugs available that address the many significant biological activities and diseases that are associated with these receptors, which is possibly due to the lack of receptor selectivity that these designed ligands are currently showing. The authors believe that further studies into the antagonists’ 3D conformational and topographical properties in addition to future mutagenesis studies will provide greater insight into these ligands which could play a role in the treatment of various diseases in the future. PMID:22646078

  2. Synergistic and antagonistic drug combinations depend on network topology. (United States)

    Yin, Ning; Ma, Wenzhe; Pei, Jianfeng; Ouyang, Qi; Tang, Chao; Lai, Luhua


    Drug combinations may exhibit synergistic or antagonistic effects. Rational design of synergistic drug combinations remains a challenge despite active experimental and computational efforts. Because drugs manifest their action via their targets, the effects of drug combinations should depend on the interaction of their targets in a network manner. We therefore modeled the effects of drug combinations along with their targets interacting in a network, trying to elucidate the relationships between the network topology involving drug targets and drug combination effects. We used three-node enzymatic networks with various topologies and parameters to study two-drug combinations. These networks can be simplifications of more complex networks involving drug targets, or closely connected target networks themselves. We found that the effects of most of the combinations were not sensitive to parameter variation, indicating that drug combinational effects largely depend on network topology. We then identified and analyzed consistent synergistic or antagonistic drug combination motifs. Synergistic motifs encompass a diverse range of patterns, including both serial and parallel combinations, while antagonistic combinations are relatively less common and homogenous, mostly composed of a positive feedback loop and a downstream link. Overall our study indicated that designing novel synergistic drug combinations based on network topology could be promising, and the motifs we identified could be a useful catalog for rational drug combination design in enzymatic systems.

  3. IAP antagonists sensitize murine osteosarcoma cells to killing by TNFα (United States)

    Shekhar, Tanmay M.; Miles, Mark A.; Gupte, Ankita; Taylor, Scott; Tascone, Brianna; Walkley, Carl R.; Hawkins, Christine J.


    Outcomes for patients diagnosed with the bone cancer osteosarcoma have not improved significantly in the last four decades. Only around 60% of patients and about a quarter of those with metastatic disease survive for more than five years. Although DNA-damaging chemotherapy drugs can be effective, they can provoke serious or fatal adverse effects including cardiotoxicity and therapy-related cancers. Better and safer treatments are therefore needed. We investigated the anti-osteosarcoma activity of IAP antagonists (also known as Smac mimetics) using cells from primary and metastatic osteosarcomas that arose spontaneously in mice engineered to lack p53 and Rb expression in osteoblast-derived cells. The IAP antagonists SM-164, GDC-0152 and LCL161, which efficiently target XIAP and cIAPs, sensitized cells from most osteosarcomas to killing by low levels of TNFα but not TRAIL. RIPK1 expression levels and activity correlated with sensitivity. RIPK3 levels varied considerably between tumors and RIPK3 was not required for IAP antagonism to sensitize osteosarcoma cells to TNFα. IAP antagonists, including SM-164, lacked mutagenic activity. These data suggest that drugs targeting XIAP and cIAP1/2 may be effective for osteosarcoma patients whose tumors express abundant RIPK1 and contain high levels of TNFα, and would be unlikely to provoke therapy-induced cancers in osteosarcoma survivors. PMID:27129149

  4. Histamine H1 antagonists and clinical characteristics of febrile seizures

    Directory of Open Access Journals (Sweden)

    Zolaly MA


    Full Text Available Mohammed A ZolalyDepartment of Pediatrics, College of Medicine, Taibah University, Al-Madinah Al-Munawarah, Kingdom of Saudi ArabiaBackground: The purpose of this study was to determine whether seizure susceptibility due to antihistamines is provoked in patients with febrile seizures.Methods: The current descriptive study was carried out from April 2009 to February 2011 in 250 infants and children who visited the Madinah Maternity and Children's Hospital as a result of febrile convulsions. They were divided into two groups according to administration of antihistamines at the onset of fever.Results: Detailed clinical manifestations were compared between patients with and without administration of antihistamines. The time from fever detection to seizure onset was significantly shorter in the antihistamine group than that in the nonantihistamine group, and the duration of seizures was significantly longer in the antihistamine group than in the nonantihistamine group. No significant difference was found in time from fever detection to seizure onset or seizure duration between patients who received a first-generation antihistamine and those who received a second-generation antihistamine.Conclusion: Due to their central nervous system effects, H1 antagonists should not be administered to patients with febrile seizures and epilepsy. Caution should be exercised regarding the use of histamine H1 antagonists in young infants, because these drugs could potentially disturb the anticonvulsive central histaminergic system.Keywords: antihistamine, nonantihistamine, histamine H1 antagonist, febrile seizures

  5. Receptor discrimination and control of agonist-antagonist binding. (United States)

    Tallarida, R J


    The law of mass action is the common model for the interaction of agonist and antagonist compounds with cellular receptors. Parameters of the interaction, obtained from functional and radioligand-binding studies, allow discrimination and subtyping of receptors and aid in understanding specific mechanisms. This article reviews the theory and associated mathematical models and graphical transformations of data that underlie the determination of receptor parameters. The main theory assumes that agonist and antagonist compounds bind to cells that have a fixed number of receptors and provides the framework for obtaining drug-receptor parameters from data and their graphical transformations. Conditions that produce a change in receptor number, a newer concept in pharmacology, can have an important effect on the parameter values derived in the usual way. This review concludes with a discussion of the quantitative study of receptor-mediated feedback control of endogenous ligands, a very new topic with potentially important implications for understanding antagonist effectiveness, loss of control, and chaos in regulated mass action binding.

  6. Newer calcium channel antagonists and the treatment of hypertension. (United States)

    Cummins, D F


    Calcium channel antagonists have become popular medications for the management of hypertension. These agents belong to the diphenylalkylamine, benzothiazepine, dihydropyridine, or tetralol chemical classes. Although the medications share a common pharmacological mechanism in reducing peripheral vascular resistance, clinical differences between the sub-classes can be linked to structural profiles. This heterogeneity is manifested by differences in vascular selectivity, effects on cardiac conduction and adverse events. The lack of differentiation between calcium channel antagonists in clinical trials has contributed to uncertainty associated with their impact on morbidity and mortality. Data from more recent studies in specific patient populations underscores the importance of investigating these antihypertensives as individual agents. A proposed therapeutic classification system suggests that newer agents should share the slow onset and long-acting antihypertensive effect of amlodipine. Additionally, a favourable trough-to-peak ratio has been recommended as an objective measurement of efficacy. The newer drugs, barnidipine and lacidipine, have a therapeutic profile similar to amlodipine, but trough-to-peak ratios are not substantially greater than the recommended minimum of 0.50. Aranidipine, cilnidipine and efonidipine have unique pharmacological properties that distinguish them from traditional dihydropyridines. Although clinical significance is unconfirmed, these newer options may be beneficial for patients with co-morbid conditions that preclude use of older antagonists.

  7. Kappa opioid receptor antagonist and N-methyl-D- aspartate receptor antagonist affect dynorphin- induced spinal cord electrophysiologic impairment

    Institute of Scientific and Technical Information of China (English)

    Yu Chen; Liangbi Xiang; Jun Liu; Dapeng Zhou; Hailong Yu; Qi Wang; Wenfeng Han; Weijian Ren


    The latencies of motor- and somatosensory-evoked potentials were prolonged to different degrees, and wave amplitude was obviously decreased, after injection of dynorphin into the rat subarachnoid cavity.The wave amplitude and latencies of motor- and somatosensory-evoked potentials were significantly recovered at 7 and 14 days after combined injection of dynorphin and either the kappa opioid receptor antagonist nor-binaltorphimine or the N-methyl-D-aspartate receptor antagonist MK-801.The wave amplitude and latency were similar in rats after combined injection of dynorphin and nor-binaltorphimine or MK-801.These results suggest that intrathecal injection of dynorphin causes damage to spinal cord function.Prevention of N-methyl-D-aspartate receptor or kappa receptor activation lessened the injury to spinal cord function induced by dynorphin.

  8. Anti free radical action of calcium antagonists and H1 and H2 receptors antagonists in neoplastic disease. (United States)

    della Rovere, F; Broccio, M; Granata, A; Zirilli, A; Brugnano, L; Artemisia, A; Broccio, G


    The blood of the subjects suffering from Neoplastic Disease (ND) shows phenomena of membrane peroxidation due to the presence of Free Radicals (FRs), in a quantity much greater than the one observed in the blood of healthy subjects. This can be detected either by calculating the time necessary for the formation of "Heinz bodies" (Hbs), (p < 0.00001) after oxidative stress of the blood in vitro with acetylphenylidrazine (APH), or by calculating the methemoglobin (metHb) quantity that forms after the same treatment (P < 0.00001). The statistical analyses we carried out showed that metHb formation was not affected by age, sex, smoking habits, red blood cell number, Hb, Ht or tumor staging. In this study, by using equal parameters of investigation, we noted that the blood of the subjects with ND who were previously treated with calcium-antagonists drugs and with antagonists of H1 and H2 receptors, gave results completely superimposable on the results obtained from healthy subjects, implying that the treatment had avoided the increase of FRs. Therefore we concluded that calcium-antagonists and the antagonists of the H1 and H2 receptors behave as antioxidant substances, having decreased the FRs damaging activity on the cellular membranes, thus controlling, although to a limited degree, the pejorative evolution of the disease. It is also important to remember that investigations into the ND, even possible screenings, must take into account the above said data, submitting the subjects under investigation to a pharmacological wash out, particularly with those substances which, are considered to be scavengers of FRs. Some of these substances are investigated in this work.

  9. Conformational studies of 3-amino-1-alkyl-cyclopentane carboxamide CCR2 antagonists leading to new spirocyclic antagonists. (United States)

    Pasternak, Alexander; Goble, Stephen D; Doss, George A; Tsou, Nancy N; Butora, Gabor; Vicario, Pasquale P; Ayala, Julia Marie; Struthers, Mary; Demartino, Julie A; Mills, Sander G; Yang, Lihu


    In an effort to shed light on the active binding conformation of our 3-amino-1-alkyl-cyclopentane carboxamide CCR2 antagonists, we prepared several conformationally constrained analogs resulting from backbone cyclization. Evaluation of CCR2 binding affinities for these analogs gave insight into the optimal relative positions of the piperidine and benzylamide moieties while simultaneously leading to the discovery of a new, potent lead type based upon a spirocyclic acetal scaffold.

  10. The selective 5-HT1A receptor antagonist WAY-100635 inhibits neuronal activity of the ventromedial prefrontal cortex in a rodent model of Parkinson' s disease%选择性5-HT1A受体拮抗剂WAY-100635抑制帕金森病模型大鼠腹内侧前额叶皮质的神经活动

    Institute of Scientific and Technical Information of China (English)

    曹健; 刘健; 张巧俊; 王涛; 王爽; 韩玲娜; 李强


    目的 腹内侧前额叶皮质在随意运动的起始和控制、情感以及认知中具有重要作用.然而,黑质-纹状体通路变性后腹内侧前额叶皮质的神经活动和5-HT1A受体的作用仍不清楚.本研究观察了6-羟基多巴胺(6-hydroxydopamine,6-OHDA)损毁黑质致密部(substantia nigra pars compacta,SNc)后大鼠腹内侧前额叶皮质神经活动的变化和体循环给予选择性5-HT1A受体拮抗剂WAY-100635后神经元活动的改变.方法 采用在体玻璃微电极细胞外记录方法,记录正常大鼠和SNc单侧损毁大鼠的腹内侧前额叶皮质神经元的活动.结果 6-OHDA损毁SNc大鼠的腹内侧前额叶皮质神经元放电频率显著增加,放电形式没有明显改变.体循环给予WAY-100635(0.1 mg/kg,i.v.)不改变正常大鼠腹内侧前额叶皮质神经元的平均放电频率和放电形式,而显著降低了SNc损毁大鼠前额叶皮质神经元的平均放电频率.结论 黑质-纹状体通路的变性可导致腹内侧前额叶皮质神经活动增强,5-HT1A受体拮抗剂WAY-100635可以抑制这种活动增强,提示可能存在腹内侧前额叶皮质5-HT1A受体功能失调.%Objective The ventral part of the medial prefrontal cortex (mPFC) plays an important role in initiation and control of voluntary movement, mood and cognition. However, after the degeneration of the nigrostriatal pathway, the neuronal activity of the ventral mPFC and the role of serotonin1A (5-hydroxytryptamine, 5-HT1A) receptors in the firing of the neurons are still unknown. The present study is to investigate the change of neuronal activity in the ventral mPFC and the effect of systemic administration of the selective 5-HT1A receptor antagonist WAY- 100635 on the activity of the neurons in normal and 6-hydroxydopamine (6-OHDA)-lesioned rats. Methods Single unit responses were recorded extracellularly with glass microelectrodes from ventral mPFC neurons in normal rats and 6-OHDA unilaterally lesiond rats in vivo

  11. The Administration of Levocabastine, a NTS2 Receptor Antagonist, Modifies Na(+), K(+)-ATPase Properties. (United States)

    Gutnisky, Alicia; López Ordieres, María Graciela; Rodríguez de Lores Arnaiz, Georgina


    Neurotensin behaves as a neuromodulator or as a neurotransmitter interacting with NTS1 and NTS2 receptors. Neurotensin in vitro inhibits synaptosomal membrane Na(+), K(+)-ATPase activity. This effect is prevented by administration of SR 48692 (antagonist for NTS1 receptor). The administration of levocabastine (antagonist for NTS2 receptor) does not prevent Na(+), K(+)-ATPase inhibition by neurotensin when the enzyme is assayed with ATP as substrate. Herein levocabastine effect on Na(+), K(+)-ATPase K(+) site was explored. For this purpose, levocabastine was administered to rats and K(+)-p-nitrophenylphosphatase (K(+)-p-NPPase) activity in synaptosomal membranes and [(3)H]-ouabain binding to cerebral cortex membranes were assayed in the absence (basal) and in the presence of neurotensin. Male Wistar rats were administered with levocabastine (50 μg/kg, i.p., 30 min) or the vehicle (saline solution). Synaptosomal membranes were obtained from cerebral cortex by differential and gradient centrifugation. The activity of K(+)-p-NPPase was determined in media laking or containing ATP plus NaCl. In such phosphorylating condition enzyme behaviour resembles that observed when ATP hydrolyses is recorded. In the absence of ATP plus NaCl, K(+)-p-NPPase activity was similar for levocabastine or vehicle injected (roughly 11 μmole hydrolyzed substrate per mg protein per hour). Such value remained unaltered by the presence of 3.5 × 10(-6) M neurotensin. In the phosphorylating medium, neurotensin decreased (32 %) the enzyme activity in membranes obtained from rats injected with the vehicle but failed to alter those obtained from rats injected with levocabastine. Levocabastine administration enhanced (50 %) basal [(3)H]-ouabain binding to cerebral cortex membranes but failed to modify neurotensin inhibitory effect on this ligand binding. It is concluded that NTS2 receptor blockade modifies the properties of neuronal Na(+), K(+)-ATPase and that neurotensin effect on Na(+), K

  12. Expression and Efficient One-Step Chromatographic Purification of a Soluble Antagonist for Human Leukemia Inhibitory Factor Receptor in Escherichia coli. (United States)

    Kim, Eun-Yeong; Choi, Hee-Jung; Chung, Tae-Wook; Jang, Se Bok; Kim, Kibong; Ha, Ki-Tae


    Leukemia inhibitory factor (LIF) is a member of the IL-6 cytokine family, having pleiotropic actions such as maintaining stem cell pluripotency and enabling blastocyst implantation. Because the action of LIF is mediated by a ligand-receptor interaction with the LIF receptor (LIF-R), an antagonist for LIF-R has been developed to inhibit LIF-induced signaling. In this study, we present a novel method for the production and purification of an antagonist to human LIF-R (hLA). His-tagged hLA was expressed in E. coli, and simple purification methods without any endopeptidase cleavage were designed. In addition, we determined the optimal temperature conditions for enhancing the production of soluble hLA. Finally, the bioactivity of His-tagged hLA was examined using STAT3 phosphorylation and receptivity of human endometrial ECC-1 cells. Our strategy provides a rapid and efficient method to produce biologically active recombinant hLA.

  13. Topical non-peptide antagonists of sensory neurotransmitters substance P and CGRP do not modify patch test and prick test reactions

    DEFF Research Database (Denmark)

    Wallengren, Joanna; Edvinsson, Lars


    developed. Their effect on the skin barrier was measured in terms of transepidermal water loss (TEWL) while permeation was calculated using permeation coefficients. Patch tests in patients allergic to nickel and prick test reactions to histamine were used as models. None of the treatments increased TEWL...... vasoconstriction in the skin but did not change the infiltration of nickel reactions. None of the treatments influenced the nickel patch test induced pruritus. The data suggest that the topical application of non-peptide antagonists penetrates the skin but does not inhibit contact dermatitis or pruritus.......Immunologic responses in the skin can be modulated by such neurotransmitters of sensory nerve fibers as substance P (SP) and calcitonin gene-related peptide (CGRP). The first-generation receptor antagonists were peptides with large molecules and had to be injected intracutaneously. The aim...

  14. Isolation of bacteria producing chitinase and inhibiting growth of Rhizoctonia solani

    Institute of Scientific and Technical Information of China (English)


    @@ Five bacteria strains with higher chitinase activity were isolated by using a technique of enriched cell wall of R. solani. All of them showed inhibiting effect on the growth of R. solani. Being cultured 3 d, strain CH-1 showed higher chitinase activity on the chitin plate. The diameter of the transparent circle reached 8.7 mm (4 replications) . In the antagonistic test to R. solani in PDA plate, the circle was 18.1 mm. It was also observed that the antagonistic ability of some strains was not consistent with the chitinase activity (Table 1). It may be connected with the secretion of chitinase at different culture situations.

  15. Does protein binding modulate the effect of angiotensin II receptor antagonists?

    Directory of Open Access Journals (Sweden)

    Marc P Maillard


    Full Text Available IntroductionAngiotensin II AT 1-receptor antagonists are highly bound to plasma proteins (≥ 99%. With some antagonists, such as DuP-532, the protein binding was such that no efficacy of the drug could be demonstrated clinically. Whether protein binding interferes with the efficacy of other antagonists is not known. We have therefore investigated in vitro how plasma proteins may affect the antagonistic effect of different AT1-receptor antagonists.MethodsA radio-receptor binding assay was used to analyse the interaction between proteins and the ability of various angiotensin II (Ang II antagonists to block AT1-receptors. In addition, the Biacore technology, a new technique which enables the real-time monitoring of binding events between two molecules, was used to evaluate the dissociation rate constants of five AT1-receptor antagonists from human serum albumin.ResultsThe in vitro AT 1-antagonistic effects of different Ang II receptor antagonists were differentially affected by the presence of human plasma, with rightward shifts of the IC50 ranging from one to several orders of magnitude. The importance of the shift correlates with the dissociation rate constants of these drugs from albumin. Our experiments also show that the way that AT1-receptor antagonists bind to proteins differs from one compound to another. These results suggest that the interaction with plasma proteins appears to modulate the efficacy of some Ang II antagonists.ConclusionAlthough the high binding level of Ang II receptor antagonist to plasma proteins appears to be a feature common to this class of compounds, the kinetics and characteristics of this binding is of great importance. With some antagonists, protein binding interferes markedly with their efficacy to block AT1-receptors.

  16. Classification and virtual screening of androgen receptor antagonists. (United States)

    Li, Jiazhong; Gramatica, Paola


    Computational tools, such as quantitative structure-activity relationship (QSAR), are highly useful as screening support for prioritization of substances of very high concern (SVHC). From the practical point of view, QSAR models should be effective to pick out more active rather than inactive compounds, expressed as sensitivity in classification works. This research investigates the classification of a big data set of endocrine-disrupting chemicals (EDCs)-androgen receptor (AR) antagonists, mainly aiming to improve the external sensitivity and to screen for potential AR binders. The kNN, lazy IB1, and ADTree methods and the consensus approach were used to build different models, which improve the sensitivity on external chemicals from 57.1% (literature) to 76.4%. Additionally, the models' predictive abilities were further validated on a blind collected data set (sensitivity: 85.7%). Then the proposed classifiers were used: (i) to distinguish a set of AR binders into antagonists and agonists; (ii) to screen a combined estrogen receptor binder database to find out possible chemicals that can bind to both AR and ER; and (iii) to virtually screen our in-house environmental chemical database. The in silico screening results suggest: (i) that some compounds can affect the normal endocrine system through a complex mechanism binding both to ER and AR; (ii) new EDCs, which are nonER binders, but can in silico bind to AR, are recognized; and (iii) about 20% of compounds in a big data set of environmental chemicals are predicted as new AR antagonists. The priority should be given to them to experimentally test the binding activities with AR.

  17. Sexually antagonistic "zygotic drive" of the sex chromosomes.

    Directory of Open Access Journals (Sweden)

    William R Rice


    Full Text Available Genomic conflict is perplexing because it causes the fitness of a species to decline rather than improve. Many diverse forms of genomic conflict have been identified, but this extant tally may be incomplete. Here, we show that the unusual characteristics of the sex chromosomes can, in principle, lead to a previously unappreciated form of sexual genomic conflict. The phenomenon occurs because there is selection in the heterogametic sex for sex-linked mutations that harm the sex of offspring that does not carry them, whenever there is competition among siblings. This harmful phenotype can be expressed as an antagonistic green-beard effect that is mediated by epigenetic parental effects, parental investment, and/or interactions among siblings. We call this form of genomic conflict sexually antagonistic "zygotic drive", because it is functionally equivalent to meiotic drive, except that it operates during the zygotic and postzygotic stages of the life cycle rather than the meiotic and gametic stages. A combination of mathematical modeling and a survey of empirical studies is used to show that sexually antagonistic zygotic drive is feasible, likely to be widespread in nature, and that it can promote a genetic "arms race" between the homo- and heteromorphic sex chromosomes. This new category of genomic conflict has the potential to strongly influence other fundamental evolutionary processes, such as speciation and the degeneration of the Y and W sex chromosomes. It also fosters a new genetic hypothesis for the evolution of enigmatic fitness-reducing traits like the high frequency of spontaneous abortion, sterility, and homosexuality observed in humans.

  18. [The antagonistic effect of aspirin on the expression of prostaglandin participation in the antihypertensive activity of ACE inhibitors]. (United States)

    Alimento, M; Campodonico, J; Santambrogio, G; Rossi, M; Trabattoni, D; Celeste, F; Guazzi, M


    ACE-inhibitors antagonize both angiotensin production and bradykinin breakdown, resulting in enhancement of vasodilating prostaglandin release. This provides an explanation for the experimental observation that cycloxygenase blockers (such as aspirin or indomethacin) may counteract the antihypertensive efficacy of the ACE-inhibitors; it may be also possible that hypertensive patients taking aspirin as an antiplatelet agent may fail to benefit from ACE-inhibition. This study was aimed at: evaluating the magnitude and incidence of the inhibitory phenomenon; defining the minimal aspirin dosage that produces an antagonistic effect, as well as the possible reasons for a different individual susceptibility. We have studied untreated patients with mild (10 cases, Group 1), moderate (16 cases, Group 2) or severe (26 cases, Group 3) hypertension. The ACE-inhibitor enalapril was used at doses of 10 mg bid (groups 1 and 2) or 20 mg bid (Group 3). Active drug treatment periods had a 5-day duration. A daily dose of aspirin of 100 mg had no effect on the antihypertensive efficacy of enalapril. On the contrary, when a dose of 300 mg was used, 60, 57 and 50% of patients in Group 1, 2 and 3, respectively, showed a > 20% restraint of the mean arterial pressure fall with enalapril (20% was the lower arbitrary limit for defining antagonism). Inhibition was independent of the sequence of drug administration. In these patients counteraction averaged 60, 70 and 90%, respectively. In them, and not in the remaining patients in each group, aspirin substantially attenuated the renin rise elicited by ACE-inhibition. These data suggest that: a dosage of 100 mg aspirin is devoid of any inhibitory effect; more that 50% of ACE inhibited patients are, at least in the short term, susceptible to the action of 300 mg aspirin, regardless of the severity of hypertension; counteraction is seemingly mediated through a prostaglandin inhibition and depends on the individual predominance of prostaglandin

  19. Platelet reactivity after administration of third generation P2Y12-antagonists does not depend on body weight in contrast to clopidogrel. (United States)

    Olivier, Christoph B; Schnabel, Katharina; Weber, Susanne; Zhou, Qian; Bode, Christoph; Moser, Martin; Diehl, Philipp


    The current standard of antiplatelet therapy for patients with myocardial infarction (MI) includes the P2Y12-receptor antagonist clopidogrel, prasugrel or ticagrelor. While it has been shown that platelet reactivity after clopidogrel administration depends on factors such as body weight, it is not known if these factors have an effect on the activity of prasugrel or ticagrelor. Thus, this study aimed to analyse factors associated with high residual platelet reactivity after administration of third generation P2Y12-antagonists compared to clopidogrel. In a single centre registry the antiplatelet effect of clopidogrel, prasugrel or ticagrelor was investigated by aggregometry in patients after MI. To assess the overall capacity of platelet aggregation whole blood was induced with thrombin receptor activating peptide (TRAP; 32 µM). To specifically quantify the effect of P2Y12-antagonists, blood was stimulated with 6.4 µM adenosine diphophosphate (ADP). Relative ADP induced aggregation (r-ADP-agg) was defined as the ADP-TRAP-ratio to reflect an individual degree of P2Y12-dependent platelet inhibition. Platelet function of 238 patients was analysed [clopidogrel (n = 58), prasugrel (n = 65), ticagrelor (n = 115)]. It was found that the r-ADP-agg correlated significantly with body weight in patients after clopidogrel administration (r = 0.423; p clopidogrel, platelet reactivity after administration of prasugrel or ticagrelor does not depend on body weight in patients after MI. Hence, our mechanistic data support the results of large clinical trials indicating that patients with high body weight do not need to be treated with increased doses of third generation P2Y12-antagonists to achieve sufficient platelet inhibition (registry for patients after myocardial infarction treated with antiplatelet agents; DRKS00003146).

  20. Fenobam: a clinically validated nonbenzodiazepine anxiolytic is a potent, selective, and noncompetitive mGlu5 receptor antagonist with inverse agonist activity. (United States)

    Porter, Richard H P; Jaeschke, Georg; Spooren, Will; Ballard, Theresa M; Büttelmann, Bernd; Kolczewski, Sabine; Peters, Jens-Uwe; Prinssen, Eric; Wichmann, Jürgen; Vieira, Eric; Mühlemann, Andreas; Gatti, Silvia; Mutel, Vincent; Malherbe, Pari


    Fenobam [N-(3-chlorophenyl)-N'-(4,5-dihydro-1-methyl-4-oxo-1H-imidazole-2-yl)urea] is an atypical anxiolytic agent with unknown molecular target that has previously been demonstrated both in rodents and human to exert anxiolytic activity. Here, we report that fenobam is a selective and potent metabotropic glutamate (mGlu)5 receptor antagonist acting at an allosteric modulatory site shared with 2-methyl-6-phenylethynyl-pyridine (MPEP), the protypical selective mGlu5 receptor antagonist. Fenobam inhibited quisqualate-evoked intracellular calcium response mediated by human mGlu5 receptor with IC(50) = 58 +/- 2 nM. It acted in a noncompetitive manner, similar to MPEP and demonstrated inverse agonist properties, blocking 66% of the mGlu5 receptor basal activity (in an over expressed cell line) with an IC(50) = 84 +/- 13 nM. [(3)H]Fenobam bound to rat and human recombinant receptors with K(d) values of 54 +/- 6 and 31 +/- 4 nM, respectively. MPEP inhibited [(3)H]fenobam binding to human mGlu5 receptors with a K(i) value of 6.7 +/- 0.7 nM, indicating a common binding site shared by both allosteric antagonists. Fenobam exhibits anxiolytic activity in the stress-induced hyperthermia model, Vogel conflict test, Geller-Seifter conflict test, and conditioned emotional response with a minimum effective dose of 10 to 30 mg/kg p.o. Furthermore, fenobam is devoid of GABAergic activity, confirming previous reports that fenobam acts by a mechanism distinct from benzodiazepines. The non-GABAergic activity of fenobam, coupled with its robust anxiolytic activity and reported efficacy in human in a double blind placebo-controlled trial, supports the potential of developing mGlu5 receptor antagonists with an improved therapeutic window over benzodiazepines as novel anxiolytic agents.

  1. Discovery of dopamine D₄ receptor antagonists with planar chirality. (United States)

    Sanna, Fabrizio; Ortner, Birgit; Hübner, Harald; Löber, Stefan; Tschammer, Nuska; Gmeiner, Peter


    Employing the D4 selective phenylpiperazine 2 as a lead compound, planar chiral analogs with paracyclophane substructure were synthesized and evaluated for their ability to bind and activate dopamine receptors. The study revealed that the introduction of a [2.2]paracyclophane moiety is tolerated by dopamine receptors of the D2 family. Subtype selectivity for D4 and ligand efficacy depend on the absolute configuration of the test compounds. Whereas the achiral single-layered lead 2 and the double-layered paracyclophane (R)-3 showed partial agonist properties, the enantiomer (S)-3 behaved as a neutral antagonist.

  2. Lymphocyte homing antagonists in the treatment of inflammatory bowel diseases. (United States)

    Saruta, Masayuki; Papadakis, Konstantinos A


    Lymphocyte homing antagonists represent promising therapeutic agents for the treatment of idiopathic inflammatory bowel disease (IBD). Several critical molecules involved in the recruitment of inflammatory cells in the intestine, including integrins and chemokine receptors, have been successfully targeted for the treatment of IBD. These agents have shown great promise for the induction and maintenance of remission for both Crohn disease and ulcerative colitis. This article discusses currently approved prototypic agents for the treatment of IBD (natalizumab, anti-α4 integrin; vedolizumab, anti-α4β7 integrin), and several other agents in the same class currently under development.

  3. The opiate antagonist, naltrexone, in the treatment of trichotillomania

    DEFF Research Database (Denmark)

    Grant, Jon E; Odlaug, Brian Lawrence; Schreiber, Liana R N;


    Trichotillomania (TTM) is characterized by repetitive hair pulling resulting in hair loss. Data on the pharmacological treatment of TTM are limited. This study examined the opioid antagonist, naltrexone, in adults with TTM who had urges to pull their hair. Fifty-one individuals with TTM were...... improved with naltrexone (P = 0.026). Subjects taking naltrexone with a family history of addiction showed a greater numerical reduction in the urges to pull, although it was not statistically significant. Future studies will have to examine whether pharmacological modulation of the opiate system may...

  4. Estrogen Receptor Agonists and Antagonists in the Yeast Estrogen Bioassay. (United States)

    Wang, Si; Bovee, Toine F H


    Cell-based bioassays can be used to predict the eventual biological activity of a substance on a living organism. In vitro reporter gene bioassays are based on recombinant vertebrate cell lines or yeast strains and especially the latter are easy-to-handle, cheap, and fast. Moreover, yeast cells do not express estrogen, androgen, progesterone or glucocorticoid receptors, and are thus powerful tools in the development of specific reporter gene systems that are devoid of crosstalk from other hormone pathways. This chapter describes our experience with an in-house developed RIKILT yeast estrogen bioassay for testing estrogen receptor agonists and antagonists, focusing on the applicability of the latter.

  5. Control of Wilt and Rot Pathogens of Tomato by Antagonistic Pink Pigmented Facultative Methylotrophic Delftia lacustris and Bacillus spp. (United States)

    Janahiraman, Veeranan; Anandham, Rangasamy; Kwon, Soon W.; Sundaram, Subbiah; Karthik Pandi, Veeranan; Krishnamoorthy, Ramasamy; Kim, Kiyoon; Samaddar, Sandipan; Sa, Tongmin


    The studies on the biocontrol potential of pink pigmented facultative methylotrophic (PPFM) bacteria other than the genus Methylobacterium are scarce. In the present study, we report three facultative methylotrophic isolates; PPO-1, PPT-1, and PPB-1, respectively, identified as Delftia lacustris, Bacillus subtilis, and Bacillus cereus by 16S rRNA gene sequence analysis. Hemolytic activity was tested to investigate the potential pathogenicity of isolates to plants and humans, the results indicates that the isolates PPO-1, PPT-1, and PPB-1 are not pathogenic strains. Under in vitro conditions, D. lacustris PPO-1, B. subtilis PPT-1, and B. cereus PPB-1 showed direct antagonistic effect by inhibiting the mycelial growth of fungal pathogens; Fusarium oxysporum f. sp. lycopersici (2.15, 2.05, and 1.95 cm), Sclerotium rolfsii (2.14, 2.04, and 1.94 cm), Pythium ultimum (2.12, 2.02, and 1.92 cm), and Rhizoctonia solani (2.18, 2.08, and 1.98 cm) and also produced volatile inhibitory compounds. Under plant growth chamber condition methylotrophic bacterial isolates; D. lacustris PPO-1, B. subtilis PPT-1, and B. cereus PPB-1 significantly reduced the disease incidence of tomato. Under greenhouse condition, D. lacustris PPO-1, B. subtilis PPT-1, and B. cereus PPB-1 inoculated tomato plants, when challenged with F. oxysporum f. sp. lycopersici, S. rolfsii, P. ultimum, and R. solani, increased the pathogenesis related proteins (β-1,3-glucanase and chitinase) and defense enzymes (phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, and catalase) on day 5 after inoculation. In the current study, we first report the facultative methylotrophy in pink pigmented D. lacustris, B. subtilis, and B. cereus and their antagonistic potential against fungal pathogens. Direct antagonistic and ISR effects of these isolates against fungal pathogens of tomato evidenced their possible use as a biocontrol agent. PMID:27872630

  6. Inhibitory effects of antagonists of growth hormone-releasing hormone on growth and invasiveness of PC3 human prostate cancer. (United States)

    Muñoz-Moreno, Laura; Arenas, M Isabel; Schally, Andrew V; Fernández-Martínez, Ana B; Zarka, Elías; González-Santander, Marta; Carmena, María J; Vacas, Eva; Prieto, Juan C; Bajo, Ana M


    New approaches are needed to the therapy of advanced prostate cancer. This study determined the effect of growth hormone-releasing hormone (GHRH) antagonists, JMR-132 and JV-1-38 on growth of PC3 tumors as well as on angiogenesis and metastasis through the evaluation of various factors that contribute largely to the progression of prostate cancer. Human PC3 androgen-independent prostate cancer cells were injected subcutaneously into nude mice. The treatment with JMR-132 (10 μg/day) or JV-1-38 (20 μg/day) lasted 41 days. We also evaluated the effects of JMR-132 and JV-1-38 on proliferation, cell adhesion and migration in PC-3 cells in vitro. Several techniques (Western blot, reverse transcription polymerase chain reaction, immunohistochemistry, ELISA and zymography) were used to evaluate the expression levels of GHRH receptors and its splice variants, GHRH, vascular endothelial growth factor (VEGF), hypoxia inducible factor (HIF)-1α, metalloproteinases (MMPs) -2 and -9, β-catenin and E-cadherin. GHRH antagonists suppressed the proliferation of PC-3 cells in vitro and significantly inhibited growth of PC3 tumors. After treatment with these analogues, we found an increase in expression of GHRH receptor accompanied by a decrease of GHRH levels, a reduction in both VEGF and HIF-1α expression and in active forms of MMP-2 and MMP-9, a significant increase in levels of membrane-associated β-catenin and a significant decline in E-cadherin. These results support that the blockade of GHRH receptors can modulate elements involved in angiogenesis and metastasis. Consequently, GHRH antagonists could be considered as suitable candidates for therapeutic trials in the management of androgen-independent prostate cancer.

  7. Antiproliferative effect of growth hormone-releasing hormone (GHRH antagonist on ovarian cancer cells through the EGFR-Akt pathway

    Directory of Open Access Journals (Sweden)

    Varga Jozsef


    Full Text Available Abstract Background Antagonists of growth hormone-releasing hormone (GHRH are being developed for the treatment of various human cancers. Methods MTT assay was used to test the proliferation of SKOV3 and CaOV3. The splice variant expression of GHRH receptors was examined by RT-PCR. The expression of protein in signal pathway was examined by Western blotting. siRNA was used to block the effect of EGFR. Results In this study, we investigated the effects of a new GHRH antagonist JMR-132, in ovarian cancer cell lines SKOV3 and CaOV3 expressing splice variant (SV1 of GHRH receptors. MTT assay showed that JMR-132 had strong antiproliferative effects on SKOV3 and CaOV3 cells in both a time-dependent and dose-dependent fashion. JMR-132 also induced the activation and increased cleaved caspase3 in a time- and dose-dependent manner in both cell lines. In addition, JMR-132 treatments decreased significantly the epidermal growth factor receptor (EGFR level and the phosphorylation of Akt (p-Akt, suggesting that JMR-132 inhibits the EGFR-Akt pathway in ovarian cancer cells. More importantly, treatment of SKOV3 and CaOV3 cells with 100 nM JMR-132 attenuated proliferation and the antiapoptotic effect induced by EGF in both cell lines. After the knockdown of the expression of EGFR by siRNA, the antiproliferative effect of JMR-132 was abolished in SKOV3 and CaOV3 cells. Conclusions The present study demonstrates that the inhibitory effect of the GHRH antagonist JMR-132 on proliferation is due, in part, to an interference with the EGFR-Akt pathway in ovarian cancer cells.

  8. Suppression of human prostate cancer cell growth by alpha1-adrenoceptor antagonists doxazosin and terazosin via induction of apoptosis. (United States)

    Kyprianou, N; Benning, C M


    Recent evidence from our laboratory has demonstrated that alpha1-adrenoceptor antagonists doxazosin and terazosin induced apoptosis in prostate epithelial and smooth muscle cells in patients with benign prostatic hypertrophy (BPH; J. Urol., 159: 1810-1815, 1998; J. Urol., 161: 2002-2007, 1999). In this study, we investigated the biological action of three alpha1-adrenoceptor antagonists, doxazosin, terazosin, and tamsulosin, against prostate cancer cell growth. The antigrowth effect of the three alpha1-adrenoceptor antagonists was examined in two human prostate cancer cell lines, PC-3 and DU-145, and a prostate smooth muscle cell primary culture, SMC-1, on the basis of: (a) cell viability assay; (b) rate of DNA synthesis; and (c) induction of apoptosis. Our results indicate that treatment of prostate cancer cells with doxazosin or terazosin results in a significant loss of cell viability, via induction of apoptosis in a dose-dependent manner, whereas tamsulosin had no effect on prostate cell growth. Neither doxazosin nor terazosin exerted a significant effect on the rate of cell proliferation in prostate cancer cells. Exposure to phenoxybenzamine, an irreversible inhibitor of alpha1-adrenoceptors, does not abrogate the apoptotic effect of doxazosin or terazosin against human prostate cancer or smooth muscle cells. This suggests that the apoptotic activity of doxazosin and terazosin against prostate cells is independent of their capacity to antagonize alpha1-adrenoceptors. Furthermore, an in vivo efficacy trial demonstrated that doxazosin administration (at tolerated pharmacologically relevant doses) in SCID mice bearing PC-3 prostate cancer xenografts resulted in a significant inhibition of tumor growth. These findings demonstrate the ability of doxazosin and terazosin (but not tamsulosin) to suppress prostate cancer cell growth in vitro and in vivo by inducing apoptosis without affecting cell proliferation. This evidence provides the rationale for targeting both

  9. Control of wilt and rot pathogens of tomato by antagonistic pink pigmented facultative methylotrophic Delftia lacustris and Bacillus spp.

    Directory of Open Access Journals (Sweden)

    Veeranan Janahiraman


    Full Text Available The studies on the biocontrol potential of pink pigmented facultative methylotrophic (PPFM bacteria other than the genus Methylobacterium are scarce. In the present study, we report three facultative methylotrophic isolates; PPO-1, PPT-1 and PPB-1, respectively identified as Delftia lacustris, Bacillus subtilis and Bacillus cereus by 16S rRNA gene sequence analysis. Hemolytic activity was tested to investigate the potential pathogenicity of isolates to plants and humans, the results indicates that the isolates PPO-1, PPT-1 and PPB-1 are not pathogenic strains. Under in vitro conditions, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 showed direct antagonistic effect by inhibiting the mycelial growth of fungal pathogens; Fusarium oxysporum f. sp. lycopersici (2.15, 2.05 and 1.95 cm, Sclerotium rolfsii (2.14, 2.04 and1.94 cm, Pythium ultimum (2.12, 2.02 and 1.92cm, and Rhizoctonia solani (2.18, 2.08 and 1.98 cm and also produced volatile inhibitory compounds. Under plant growth chamber condition methylotrophic bacterial isolates; D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 significantly reduced the disease incidence of tomato. Under greenhouse condition, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 inoculated tomato plants, when challenged with F. oxysporum f. sp. lycopersici, S. rolfsii, P. ultimum and R. solani, increased the pathogenesis related proteins (β-1, 3-glucanase and chitinase and defense enzymes (phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, and catalase on day 5 after inoculation. In the current study, we first report the facultative methylotrophy in pink pigmented Delftia lacustris, B. subtilis, and B. cereus and their antagonistic potential against fungal pathogens. Direct antagonistic and ISR effects of these isolates against fungal pathogens of tomato evidenced their possible use as a biocontrol agent.

  10. Volatile organic compounds: a potential direct long-distance mechanism for antagonistic action of Fusarium oxysporum strain MSA 35. (United States)

    Minerdi, Daniela; Bossi, Simone; Gullino, Maria Lodovica; Garibaldi, Angelo


    Fusarium oxysporum MSA35 [wild-type (WT) strain] is an antagonistic Fusarium that lives in association with a consortium of bacteria belonging to the genera Serratia, Achromobacter, Bacillus and Stenotrophomonas in an Italian soil suppressive to Fusarium wilt. Typing experiments and virulence tests provided evidence that the F. oxysporum isolate when cured of the bacterial symbionts [the cured (CU) form], is pathogenic, causing wilt symptoms identical to those caused by F. oxysporum f. sp. lactucae. Here, we demonstrate that small volatile organic compounds (VOCs) emitted from the WT strain negatively influence the mycelial growth of different formae speciales of F. oxysporum. Furthermore, these VOCs repress gene expression of two putative virulence genes in F. oxysporum lactucae strain Fuslat10, a fungus against which the WT strain MSA 35 has antagonistic activity. The VOC profile of the WT and CU fungus shows different compositions. Sesquiterpenes, mainly caryophyllene, were present in the headspace only of WT MSA 35. No sesquiterpenes were found in the volatiles of ectosymbiotic Serratia sp. strain DM1 and Achromobacter sp. strain MM1. Bacterial volatiles had no effects on the growth of the different ff. spp. of F. oxysporum examined. Hyphae grownwithVOCfrom WT F. oxysporum f. sp. lactucae strain MSA 35 were hydrophobic whereas those grown without VOCs were not, suggesting a correlation between the presence of volatiles in the atmosphere and the phenotype of the mycelium. This is the first report of VOC production by antagonistic F. oxysporum MSA35 and their effects on pathogenic F. oxysporum. The results obtained in this work led us to propose a new potential direct long-distance mechanism for antagonism by F. oxysporum MSA 35 mediated by VOCs. Antagonism could be the consequence of both reduction of pathogen mycelial growth and inhibition of pathogen virulence gene expression.

  11. The design of orally bioavailable 2, 5-diketopiperazine oxytocin antagonists: from concept to clinical candidate for premature labor. (United States)

    Borthwick, Alan D; Liddle, John


    A short, efficient and highly stereoselective synthesis has been developed for a series of 6-indanyl-3-alkyl-7-aryl/heterocyclic-(3R, 6R, 7R)-2, 5-diketopiperazine amides that are potent and selective oxytocin (OT) antagonists. Property-based design using an estimate of human oral absorption enabled focus to be directed to those templates with the greatest chance of delivering high bioavailability in humans. This led to the 2', 4'-difluorophenyl dimethylamide 40, a highly potent (pK(i) =9.2) and selective OT antagonist (>1,000-fold selectivity vs. the human vasopressin receptors V1a, V2, and V1b) with good oral bioavailability (>50%) in the rat and dog. Increased solubility and an improved Cyp450 profile was achieved with a range of 2'-substituted 7-(1',3'-oxazol-4'-yl)-(3R,6R,7R)-2,5-diketopiperazine amides and branching at the α-carbon of the 3-butyl group led to a superior rat pharmacokinetic profile that resulted in the discovery of the 2'-methyl-1',3'-oxazol-4'-yl morpholine amide derivative 74 GSK221149A (Retosiban), which had the best oral exposure and bioavailability in the rat. Retosiban has sub-nanomolar affinity (K(i) =0.65 nM) for the oxytocin receptor with >1400-fold selectivity over the closely related vasopressin receptors. It has good solubility, low protein binding and has a good Cyp450 profile with no significant inhibition IC(50) >100 µM. Retosiban is >15-fold more potent at the human oxytocin receptor than atosiban (a marketed i.v, peptide OT antagonist) and it has been shown to be an effective tocolytic by i.v. and by oral administration in rats, and was selected for progression as a potential clinical candidate for preterm labor.

  12. Influenza A virus does not encode a tetherin antagonist with Vpu-like activity and induces IFN-dependent tetherin expression in infected cells.

    Directory of Open Access Journals (Sweden)

    Michael Winkler

    Full Text Available The interferon-induced host cell factor tetherin inhibits release of human immunodeficiency virus (HIV from the plasma membrane of infected cells and is counteracted by the HIV-1 protein Vpu. Influenza A virus (FLUAV also buds from the plasma membrane and is not inhibited by tetherin. Here, we investigated if FLUAV encodes a functional equivalent of Vpu for tetherin antagonism. We found that expression of the FLUAV protein NS1, which antagonizes the interferon (IFN response, did not block the tetherin-mediated restriction of HIV release, which was rescued by Vpu. Similarly, tetherin-mediated inhibition of HIV release was not rescued by FLUAV infection. In contrast, FLUAV infection induced tetherin expression on target cells in an IFN-dependent manner. These results suggest that FLUAV escapes the antiviral effects of tetherin without encoding a tetherin antagonist with Vpu-like activity.

  13. Investigation on inhibition of biological effects of endothelin

    Institute of Scientific and Technical Information of China (English)

    田青; 赵东; 张继峰; 高连如; 刘胜昔; 杨军; 苏静怡; 张肇康; 汤健; 唐朝枢


    The effects of a series of substances on the biological function of endothelin (ET) are reported. The substances used are: synthetic inhibitors of endothelium derived relaxing factors (EDRFs), inhibitor of big-endothelin converting enzyme phosphoramidon, antiserum of endothelin, antagonists of endothelin A receptor BQ123 and JKC301, and two Chinese anti-snake venom herb medicines Lobelia radians Thumb and Taris polyphylla Smith var. chinensis (Franch) Hara. The results showed that inhibiting the production of nitric oxide (NO) could stimulate ET release from vascular endothelium, elevate plasma ET and increase blood pressure. These changes could be reversed by L-arginine (L-Arg), the substrate of nitric oxide synthase (NOS). The amount of ET released by arterial endothelium could be increased or inhibited by inhibiting or stimulating the synthesis of prostacyclin (PGI2). The plasma ET level and blood pressure in both SHR and WKY rats could be decreased by giving phosphoramidon (PhR). The above results i

  14. A maraviroc-resistant HIV-1 with narrow cross-resistance to other CCR5 antagonists depends on both N-terminal and extracellular loop domains of drug-bound CCR5. (United States)

    Tilton, John C; Wilen, Craig B; Didigu, Chukwuka A; Sinha, Rohini; Harrison, Jessamina E; Agrawal-Gamse, Caroline; Henning, Elizabeth A; Bushman, Frederick D; Martin, Jeffrey N; Deeks, Steven G; Doms, Robert W


    CCR5 antagonists inhibit HIV entry by binding to a coreceptor and inducing changes in the extracellular loops (ECLs) of CCR5. In this study, we analyzed viruses from 11 treatment-experienced patients who experienced virologic failure on treatment regimens containing the CCR5 antagonist maraviroc (MVC). Viruses from one patient developed high-level resistance to MVC during the course of treatment. Although resistance to one CCR5 antagonist is often associated with broad cross-resistance to other agents, these viruses remained sensitive to most other CCR5 antagonists, including vicriviroc and aplaviroc. MVC resistance was dependent upon mutations within the V3 loop of the viral envelope (Env) protein and was modulated by additional mutations in the V4 loop. Deep sequencing of pretreatment plasma viral RNA indicated that resistance appears to have occurred by evolution of drug-bound CCR5 use, despite the presence of viral sequences predictive of CXCR4 use. Envs obtained from this patient before and during MVC treatment were able to infect cells expressing very low CCR5 levels, indicating highly efficient use of a coreceptor. In contrast to previous reports in which CCR5 antagonist-resistant viruses interact predominantly with the N terminus of CCR5, these MVC-resistant Envs were also dependent upon the drug-modified ECLs of CCR5 for entry. Our results suggest a model of CCR5 cross-resistance whereby viruses that predominantly utilize the N terminus are broadly cross-resistant to multiple CCR5 antagonists, whereas viruses that require both the N terminus and antagonist-specific ECL changes demonstrate a narrow cross-resistance profile.

  15. Effect of transient receptor potential vanilloid 1 (TRPV1) receptor antagonist compounds SB705498, BCTC and AMG9810 in rat models of thermal hyperalgesia measured with an increasing-temperature water bath. (United States)

    Tékus, Valéria; Bölcskei, Kata; Kis-Varga, Agnes; Dézsi, László; Szentirmay, Eva; Visegrády, András; Horváth, Csilla; Szolcsányi, János; Petho, Gábor


    The transient receptor potential vanilloid 1 (TRPV1) receptor is activated by noxious heat, various endogenous mediators and exogenous irritants. The aim of the present study was to compare three TRPV1 receptor antagonists (SB705498, BCTC and AMG9810) in rat models of heat hyperalgesia. The behavioural noxious heat threshold, defined as the lowest temperature evoking nocifensive reaction, was measured with an increasing-temperature water bath. The effects of TRPV1 receptor antagonists were assessed in thermal hyperalgesia induced by the TRPV1 agonist resiniferatoxin (RTX), mild heat injury (51 degrees C, 20s) or plantar incision in rats. The control heat threshold was 43.2+/-0.4 degrees C. RTX induced an 8-10 degrees C decrease in heat threshold which was dose-dependently inhibited by oral pre-treatment with any of the TRPV1 receptor antagonists with a minimum effective dose of 1mg/kg. The mild heat injury-evoked 7-8 degrees C heat threshold drop was significantly reversed by all three antagonists injected i.p. as post-treatment. The minimum effective doses were as follows: SB705498 10, BCTC 3 and AMG9810 1mg/kg. Plantar incision-induced heat threshold drop (7-8 degrees C) was dose-dependently diminished by an oral post-treatment with any of the antagonists with minimum effective doses of 10, 3 and 3mg/kg, respectively. Assessment of RTX hyperalgesia by measurement of the paw withdrawal latency with a plantar test apparatus yielded 30 mg/kg minimum effective dose for each antagonist. In conclusion, measurement of the noxious heat threshold with the increasing-temperature water bath is suitable to sensitively detect the effects of TRPV1 receptor antagonists in thermal hyperalgesia models.

  16. SAR110894, a potent histamine H₃-receptor antagonist, displays procognitive effects in rodents. (United States)

    Griebel, Guy; Pichat, Philippe; Pruniaux, Marie-Pierre; Beeské, Sandra; Lopez-Grancha, Mati; Genet, Elisabeth; Terranova, Jean-Paul; Castro, Antonio; Sánchez, Juan Antonio; Black, Mark; Varty, Geoffrey B; Weiner, Ina; Arad, Michal; Barak, Segev; De Levie, Amaya; Guillot, Etienne


    SAR110894 is a novel histamine H₃-R ligand, displaying high and selective affinity for human, rat or mouse H₃-Rs. SAR110894 is a potent H₃-R antagonist at native receptors, reversing R-α-methylhistamine-induced inhibition of electrical field stimulation contraction in the guinea-pig ileum. Additionally, SAR110894 inhibited constitutive GTPγS binding at human H₃-Rs demonstrating inverse agonist properties. In behavioral models addressing certain aspects of cognitive impairment associated with schizophrenia (CIAS) and attention deficit/hyperactivity disorder (ADHD), SAR110894 improved memory performances in several variants of the object recognition task in mice (0.3-3 mg/kg, p.o.) or rats (0.3-1 mg/kg, p.o.). Moreover, SAR110894 (1 mg/kg, p.o.) reversed a deficit in working memory in the Y-maze test, following an acute low dose of phencyclidine (PCP) (0.5 mg/kg, i.p.) in mice sensitized by repeated treatment with a high dose of PCP (10 mg/kg, i.p.). In the latent inhibition (LI) model, SAR110894 potentiated LI in saline-treated rats (1 and 3 mg/kg, i.p.) and reversed abnormally persistent LI induced by neonatal nitric oxide synthase (NOS) inhibition in rodents (0.3-3 mg/kg, i.p.). In a social novelty discrimination task in rats, SAR110894 attenuated selective attention deficit induced by neonatal PCP treatment (3 and 10 mg/kg, p.o.) or a parametric modification of the procedure (3 and 10 mg/kg, p.o.). SAR110894 showed efficacy in several animal models related to the cognitive deficits in Alzheimer's disease (AD). It prevented the occurrence of episodic memory deficit induced by scopolamine in rats (0.01-10 mg/kg, p.o.) or by the central infusion of the toxic amyloid fragment β₂₅₋₃₅ in the object recognition test in mice (1 and 3 mg/kg, p.o.). Altogether, these findings suggest that SAR110894 may be of therapeutic interest for the treatment of the cognitive symptoms of AD, schizophrenia and certain aspects of ADHD.

  17. The evolution of histamine H₃ antagonists/inverse agonists. (United States)

    Lebois, Evan P; Jones, Carrie K; Lindsley, Craig W


    This article describes our efforts along with recent advances in the development, biological evaluation and clinical proof of concept of small molecule histamine H₃ antagonists/inverse agonists. The H3 receptor is a presynaptic autoreceptor within the Class A GPCR family, but also functions as a heteroreceptor modulating levels of neurotransmitters such as dopamine, acetylcholine, norepinephrine, serotonin, GABA and glutamate. Thus, H₃R has garnered a great deal of interest from the pharmaceutical industry for the possible treatment of obesity, epilepsy, sleep/wake, schizophrenia, Alzheimer's disease, neuropathic pain and ADHD. Within the two main classes of H₃ ligands, both imidazole and non-imidazole derived, have shown sufficient potency and specificity which culminated with efficacy in preclinical models for various CNS disorders. Importantly, conserved elements have been identified within the small molecule H₃ ligand scaffolds that resulted in a highly predictive pharmacophore model. Understanding of the pharmacophore model has allowed several groups to dial H₃R activity into scaffolds designed for other CNS targets, and engender directed polypharmacology. Moreover, Abbott, GSK, Pfizer and several others have reported positive Phase I and/or Phase II data with structurally diverse H₃R antagonists/inverse agonists.

  18. CGRP antagonists and antibodies for the treatment of migraine. (United States)

    Vécsei, László; Szok, Délia; Csáti, Anett; Tajti, János


    Introduction: Migraine is a highly devastating neurovascular disorder that affects up to 16% of the population worldwide. In spite of intensive research, its origin remains enigmatic with no therapeutic option appropriate for all migraine patients. One of the leading hypotheses is related to the function of the calcitonin gene-related peptide (CGRP). Regardless, the pharmaceutical options currently applied for the acute and prophylactic treatment of migraine are not appropriate for all migraine patients. Areas covered: This article is based on a literature review using the PubMed database and highlights the CGRP theory of the pathomechanism of migraine. Expert opinion: Since migraine is a CGRP-related disorder, it appeared obvious to develop CGRP receptor antagonists that exert high efficacy, both intravenously and orally. Unfortunately, the frequent use of these antagonists results in an elevated liver transaminase level. In an attempt to bypass these harmful side effects, efforts should be made to modify these pharmacons. The use of fully humanized monoclonal antibodies (mAbs) that target CGRP and its receptors may also be possible. However, while Phase I and II clinical trials are promising, a long-term follow-up of these therapies is still needed.

  19. Rogue sperm indicate sexually antagonistic coevolution in nematodes.

    Directory of Open Access Journals (Sweden)

    Ronald E Ellis


    Full Text Available Intense reproductive competition often continues long after animals finish mating. In many species, sperm from one male compete with those from others to find and fertilize oocytes. Since this competition occurs inside the female reproductive tract, she often influences the outcome through physical or chemical factors, leading to cryptic female choice. Finally, traits that help males compete with each other are sometimes harmful to females, and female countermeasures may thwart the interests of males, which can lead to an arms race between the sexes known as sexually antagonistic coevolution. New studies from Caenorhabditis nematodes suggest that males compete with each other by producing sperm that migrate aggressively and that these sperm may be more likely to win access to oocytes. However, one byproduct of this competition appears to be an increased probability that these sperm will go astray, invading the ovary, prematurely activating oocytes, and sometimes crossing basement membranes and leaving the gonad altogether. These harmful effects are sometimes observed in crosses between animals of the same species but are most easily detected in interspecies crosses, leading to dramatically lowered fitness, presumably because the competitiveness of the sperm and the associated female countermeasures are not precisely matched. This mismatch is most obvious in crosses involving individuals from androdioecious species (which have both hermaphrodites and males, as predicted by the lower levels of sperm competition these species experience. These results suggest a striking example of sexually antagonistic coevolution and dramatically expand the value of nematodes as a laboratory system for studying postcopulatory interactions.

  20. Human homosexuality: a paradigmatic arena for sexually antagonistic selection? (United States)

    Camperio Ciani, Andrea; Battaglia, Umberto; Zanzotto, Giovanni


    Sexual conflict likely plays a crucial role in the origin and maintenance of homosexuality in our species. Although environmental factors are known to affect human homosexual (HS) preference, sibling concordances and population patterns related to HS indicate that genetic components are also influencing this trait in humans. We argue that multilocus, partially X-linked genetic factors undergoing sexually antagonistic selection that promote maternal female fecundity at the cost of occasional male offspring homosexuality are the best candidates capable of explaining the frequency, familial clustering, and pedigree asymmetries observed in HS male proband families. This establishes male HS as a paradigmatic example of sexual conflict in human biology. HS in females, on the other hand, is currently a more elusive phenomenon from both the empirical and theoretical standpoints because of its fluidity and marked environmental influence. Genetic and epigenetic mechanisms, the latter involving sexually antagonistic components, have been hypothesized for the propagation and maintenance of female HS in the population. However, further data are needed to truly clarify the evolutionary dynamics of this trait.

  1. Comparative proteome analysis of two antagonist Bacillus subtilis strains. (United States)

    Zhang, C X; Zhao, X; Han, F; Yang, M F; Chen, H; Chida, T; Shen, S H


    Natural wild-type strains of Bacillus subtilis are extensively used in agriculture as biocontrol agents for plants. This study examined two antagonist B. subtilis strains, KB-1111 and KB-1122, and the results illustrated that KB-1122 was a more potent inhibitor of the indicator pathogen than KB- 1111. Thus, to investigate the intrinsic differences between the two antagonist strains under normal culture conditions, samples of KB-1111 and KB-1122 were analyzed using MALDI-TOF-MS. The main differences were related to 20 abundant intracellular and 17 extracellular proteins. When searching the NCBI database, a number of the differentially expressed proteins were identified, including 11 cellular proteins and 10 secretory proteins. Among these proteins, class III stress-response-related ATPase, aconitate hydratase, alpha-amylase precursor, and a secretory protein, endo-1, 4-beta-glucanase, were differentially expressed by the two strains. These results are useful to comprehend the intrinsic differences between the antagonism of KB-1111 and KB-1122.

  2. Effects of oral cetirizine, a selective H1 antagonist, on allergen- and exercise-induced bronchoconstriction in subjects with asthma.

    LENUS (Irish Health Repository)

    Gong, H


    The protective efficacy of oral cetirizine, a selective and potent H1-receptor antagonist, against the immediate bronchoconstrictive response to allergen inhalation and exercise challenge was evaluated in 16 subjects with stable, predominantly mild asthma. The subjects underwent double-blind, crossover pretreatments in randomized order in two separate protocols with (1) three daily oral doses of 20 mg of cetirizine and placebo, followed by allergen inhalation, and (2) single oral doses of cetirizine (5, 10, and 20 mg), albuterol (4 mg), and placebo, followed by exercise with cold-air inhalation. Cetirizine failed to decrease bronchial sensitivity to inhaled allergen in eight of 10 subjects. Neither cetirizine nor albuterol uniformly inhibited exercise-induced bronchoconstriction. Serum concentrations of cetirizine were consistent with systemic H1-blocking activity. Modest bronchodilation occurred after administration of cetirizine and albuterol before exercise but not after the third dose of cetirizine in the allergen protocol. One subject developed moderate drowsiness during multiple dosing with cetirizine. Thus, cetirizine, in the doses studied, is not uniformly effective in preventing allergen- or exercise-induced bronchoconstriction. Histamine is one of many mediators participating in immediate asthmatic responses, and selective H1 antagonists do not completely block these airway events. However, cetirizine may still clinically benefit some patients with asthma, such as patients with allergic rhinitis or urticaria.

  3. Blockade of murine T cell activation by antagonists of P2Y6 and P2X7 receptors. (United States)

    Tsukimoto, Mitsutoshi; Tokunaga, Akihiro; Harada, Hitoshi; Kojima, Shuji


    Extracellular nucleotides and their metabolites activate ionotropic P2X and metabotropic P2Y receptors on the surface of various types of cells. Here, we investigated the involvement of P2X and P2Y receptor-mediated signaling in TCR-dependent T cell activation. Murine T cells were activated by stimulation of TCR, and both CD25 expression and interleukin (IL)-2 production were observed in activated T cells. Ecto-nucleotidase apyrase and P2Y6 antagonist MRS2578 significantly blocked the increases of both CD25 expression and IL-2 production, and P2X7 antagonists A438079 and oxidized ATP inhibited IL-2 production rather than CD25 expression, suggesting the involvement of P2Y6 and P2X7 receptors in different processes of T cell activation. MRS2578 also blocked TCR-dependent elevation of cytosolic Ca2+ in T cells. The P2X7 and P2Y6 receptors were expressed in murine CD4 T cells. In conclusion, our results indicate that activation of P2Y6 and P2X7 receptors contributes to T cell activation via TCR.

  4. 5-HT reuptake inhibitors with 5-HT(1B/1D) antagonistic activity: a new approach toward efficient antidepressants. (United States)

    Matzen, L; van Amsterdam, C; Rautenberg, W; Greiner, H E; Harting, J; Seyfried, C A; Böttcher, H


    As part of our research program toward new, potential antidepressants, a series of unsymmetrical ureas has been prepared and evaluated as 5-HT reuptake inhibitors with 5-HT(1B/1D) antagonistic activities. The design of these compounds was based on coupling of various indole derivatives, previously shown to inhibit 5-HT reuptake, to three different aniline moieties, which are part of known 5-HT(1B/1D) ligands. Binding experiments in rat frontal cortex using [(125)I]iodocyanopindolol, in calf striatum using [(3)H]5-HT, and in rat hippocampus using [(3)H]8-OH-DPAT as radioligands, respectively, revealed significantly higher affinity at the 5-HT(1B) receptor as compared to the affinities for the 5-HT(1A) and 5-HT(1D) receptors for a number of compounds, among them 4-(5-fluoro-1H-indol-3-yl)piperidine-1-carboxylic acid [4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide (5), the corresponding 4-fluoro-1H-indol-3-yl analogue 21a, and the corresponding 6-fluoro-1H-indol-3-yl analogue 21b. Conformational restriction of the aniline moiety in 5 only slightly enhanced the 5-HT(1B) affinity, whereas introduction of an aniline moiety with higher conformational flexibility resulted in a less potent 5-HT(1B) receptor ligand as compared to 5. The functional 5-HT(1B/1D) antagonistic activity was investigated using the rabbit saphenous vein model as well as the [(3)H]5-HT release from guinea pig cortical slices. All new compounds tested in the rabbit saphenous vein model were shown to antagonize the sumatriptan-evoked contractile responses with pA(2) values ranging from 7.3 to 8.7. These observations were consistent with the results of the cortical slice model, in which the ureas were found to block the sumatriptan-induced inhibition of potassium-evoked [(3)H]5-HT release. The 5-HT reuptake inhibition of the ureas determined in rat brain synaptosomes was found to be either increased or decreased as compared to the uncoupled indole derivatives indicating that the reuptake inhibition

  5. Activation of GABA B receptors in the anterior pituitary inhibits prolactin and luteinizing hormone secretion. (United States)

    Lux-Lantos, V; Rey, E; Libertun, C


    Previous work from our laboratory showed that baclofen could lower serum prolactin (PRL) levels acting at the central nervous system. The present experiments were designed to evaluate whether the gamma-aminobutyric acid B agonist was also effective in inhibiting hormone release at the pituitary level. In monolayer cultures of adenohypophyseal dispersed cells, baclofen inhibited basal PRL secretion after 1 or 2 h of incubation. This inhibition was significantly abolished by three antagonists: phaclofen, 3-aminopropyl-phosphonic acid and 4-aminobutylphosphonic acid. Furthermore, baclofen inhibited the thyrotropin-releasing hormone-induced PRL release in a concentration-dependent manner. With regard to gonadotropin secretion, baclofen was unable to modify basal luteinizing hormone (LH) secretion, but significantly inhibited the LH-releasing hormone-induced LH release. These results show that baclofen, in addition to its central neuroendocrine effects, inhibits pituitary hormone secretion, under basal and/or stimulated conditions, by direct action at the pituitary level.

  6. LINGO-1 antagonist promotes functional recovery and axonal sprouting after spinal cord injury. (United States)

    Ji, Benxiu; Li, Mingwei; Wu, Wu-Tian; Yick, Leung-Wah; Lee, Xinhua; Shao, Zhaohui; Wang, Joy; So, Kwok-Fai; McCoy, John M; Pepinsky, R Blake; Mi, Sha; Relton, Jane K


    LINGO-1 is a CNS-specific protein and a functional component of the NgR1/p75/LINGO-1 and NgR1/TAJ(TROY)/LINGO-1 signaling complexes that mediate inhibition of axonal outgrowth. These receptor complexes mediate the axonal growth inhibitory effects of Nogo, myelin-associated glycoprotein (MAG) and oligodendrocyte-myelin glycoprotein (OMgp) via RhoA activation. Soluble LINGO-1 (LINGO-1-Fc), which acts as an antagonist of these pathways by blocking LINGO-1 binding to NgR1, was administered to rats after dorsal or lateral hemisection of the spinal cord. LINGO-1-Fc treatment significantly improved functional recovery, promoted axonal sprouting and decreased RhoA activation and increased oligodendrocyte and neuronal survival after either rubrospinal or corticospinal tract transection. These experiments demonstrate an important role for LINGO-1 in modulating axonal outgrowth in vivo and that treatment with LINGO-1-Fc can significantly enhance recovery after spinal cord injury.

  7. Associations of interleukin (IL)-1β, IL-1 receptor antagonist, and IL-10 with dental caries. (United States)

    Cogulu, Dilsah; Onay, Huseyin; Ozdemir, Yasemin; I Aslan, Gulcin; Ozkinay, Ferda; Kutukculer, Necil; Eronat, Cemal


    Streptococcus mutans is important in dental caries. Although the role of cytokines in the pathogenesis of dental caries is not clear, components of S. mutans were found to stimulate production of pro-inflammatory cytokines. We examined the associations of interleukin (IL)-1β, IL-1 receptor antagonist (IL-1ra), and IL-10 with dental caries. Unstimulated whole saliva and blood samples were obtained from 108 children aged 6-12 years with high caries (decayed, missing, or filled teeth [dmft/DMFT] index >4, n = 37), moderate caries (dmft/DMFT = 1-4, n = 37), or caries-free (dmft/DMFT = 0, n = 34). S. mutans level was classified as low (caries was not correlated with salivary or serum concentrations of the studied cytokines. S. mutans level positively correlated with saliva IL-1β concentration and inversely correlated with saliva IL-1ra concentration. There was no correlation of IL-1β, IL-1ra, or IL-10 gene polymorphisms with dental caries. S. mutans is important in stimulating saliva IL-1β and inhibiting IL-1ra. Future studies of associations between cytokines and dental caries should investigate additional cytokines and enroll a larger number of participants.

  8. LSD1 and HY5 Antagonistically Regulate Red Light induced-Programmed Cell Death in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Tingting eChai


    Full Text Available Programmed cell death (PCD in plant is triggered by abiotic and biotic stress. Light-dependent PCD is unique to plants. Light-induced PCD also requires reactive oxygen species (ROS and salicylic acid (SA. In this study, lesion simulating disease1 (LSD1 and elongated hypocotyl 5 (HY5 perform opposite roles to regulate excess red light (RL-triggered PCD associated with ROS and SA production. Under RL, the lsd1 mutant released more ROS and SA and displayed a stronger cell death rate than the hy5 mutant. It was shown that active LSD1 converted into inactive form by changing the redox status of the plastoquinone pool, and HY5 interacted with phytochrome B (phyB to promote PCD in response to RL. LSD1 inhibited the enhanced disease susceptibility 1 (EDS1 expression by upregulating SR1, whereas HY5 enhanced the enhanced EDS1 expression by binding to the G-box of the EDS1 promoter. This study suggested that LSD1 and HY5 antagonistically modulated EDS1-dependent ROS and SA signaling; thus, PCD was mediated in response to RL.

  9. LSD1 and HY5 antagonistically regulate red light induced-programmed cell death in Arabidopsis. (United States)

    Chai, Tingting; Zhou, Jun; Liu, Jian; Xing, Da


    Programmed cell death (PCD) in plant is triggered by abiotic and biotic stress. Light-dependent PCD is unique to plants. Light-induced PCD also requires reactive oxygen species (ROS) and salicylic acid (SA). In this study, lesion simulating disease1 (LSD1) and elongated hypocotyl 5 (HY5) perform opposite roles to regulate excess red light (RL)-triggered PCD associated with ROS and SA production. Under RL, the lsd1 mutant released more ROS and SA and displayed a stronger cell death rate than the hy5 mutant. It was shown that active LSD1 converted into inactive form by changing the redox status of the plastoquinone pool, and HY5 interacted with phytochrome B (phyB) to promote PCD in response to RL. LSD1 inhibited the enhanced disease susceptibility 1 (EDS1) expression by upregulating SR1, whereas HY5 enhanced the enhanced EDS1 expression by binding to the G-box of the EDS1 promoter. This study suggested that LSD1 and HY5 antagonistically modulated EDS1-dependent ROS and SA signaling; thus, PCD was mediated in response to RL.

  10. DREAM (Downstream Regulatory Element Antagonist Modulator contributes to synaptic depression and contextual fear memory

    Directory of Open Access Journals (Sweden)

    Wu Long-Jun


    Full Text Available Abstract The downstream regulatory element antagonist modulator (DREAM, a multifunctional Ca2+-binding protein, binds specifically to DNA and several nucleoproteins regulating gene expression and with proteins outside the nucleus to regulate membrane excitability or calcium homeostasis. DREAM is highly expressed in the central nervous system including the hippocampus and cortex; however, the roles of DREAM in hippocampal synaptic transmission and plasticity have not been investigated. Taking advantage of transgenic mice overexpressing a Ca2+-insensitive DREAM mutant (TgDREAM, we used integrative methods including electrophysiology, biochemistry, immunostaining, and behavior tests to study the function of DREAM in synaptic transmission, long-term plasticity and fear memory in hippocampal CA1 region. We found that NMDA receptor but not AMPA receptor-mediated current was decreased in TgDREAM mice. Moreover, synaptic plasticity, such as long-term depression (LTD but not long-term potentiation (LTP, was impaired in TgDREAM mice. Biochemical experiments found that DREAM interacts with PSD-95 and may inhibit NMDA receptor function through this interaction. Contextual fear memory was significantly impaired in TgDREAM mice. By contrast, sensory responses to noxious stimuli were not affected. Our results demonstrate that DREAM plays a novel role in postsynaptic modulation of the NMDA receptor, and contributes to synaptic plasticity and behavioral memory.

  11. Antagonistic and synergistic effects of light irradiation on the effects of copper on Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Cheloni, Giulia; Cosio, Claudia; Slaveykova, Vera I., E-mail:


    Highlights: • Light intensity and spectral composition affect Cu uptake and effects to C. reinhardtii. • High light (HL) reduced Cu effect on growth inhibition, oxidative stress and damage. • HL in combination with Cu up-regulated genes involved in the antioxidant responses. • HL with increased UVB radiation exacerbated Cu uptake and Cu-induced toxic effects. - Abstract: The present study showed the important role of light intensity and spectral composition on Cu uptake and effects on green alga Chlamydomonas reinhardtii. High-intenisty light (HL) increased cellular Cu concentrations, but mitigated the Cu-induced decrease in chlorophyll fluorescence, oxidative stress and lipid peroxidation at high Cu concentrations, indicating that Cu and HL interact in an antagonistic manner. HL up-regulated the transcription of genes involved in the antioxidant response in C. reinhardtii and thus reduced the oxidative stress upon exposure to Cu and HL. Combined exposure to Cu and UVBR resulted in an increase of cellular Cu contents and caused severe oxidative damage to the cells. The observed effects were higher than the sum of the effects corresponding to exposure to UVBR or Cu alone suggesting a synergistic interaction.

  12. Histamine and Skin Barrier: Are Histamine Antagonists Useful for the Prevention or Treatment of Atopic Dermatitis? (United States)

    De Benedetto, Anna; Yoshida, Takeshi; Fridy, Sade; Park, Joo-Eun S; Kuo, I-Hsin; Beck, Lisa A


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

  13. Antagonistic cross-regulation between Wnt and Hedgehog signalling pathways controls post-embryonic retinal proliferation. (United States)

    Borday, Caroline; Cabochette, Pauline; Parain, Karine; Mazurier, Nicolas; Janssens, Sylvie; Tran, Hong Thi; Sekkali, Belaïd; Bronchain, Odile; Vleminckx, Kris; Locker, Morgane; Perron, Muriel


    Continuous neurogenesis in the adult nervous system requires a delicate balance between proliferation and differentiation. Although Wnt/β-catenin and Hedgehog signalling pathways are thought to share a mitogenic function in adult neural stem/progenitor cells, it remains unclear how they interact in this process. Adult amphibians produce retinal neurons from a pool of neural stem cells localised in the ciliary marginal zone (CMZ). Surprisingly, we found that perturbations of the Wnt and Hedgehog pathways result in opposite proliferative outcomes of neural stem/progenitor cells in the CMZ. Additionally, our study revealed that Wnt and Hedgehog morphogens are produced in mutually exclusive territories of the post-embryonic retina. Using genetic and pharmacological tools, we found that the Wnt and Hedgehog pathways exhibit reciprocal inhibition. Our data suggest that Sfrp-1 and Gli3 contribute to this negative cross-regulation. Altogether, our results reveal an unexpected antagonistic interplay of Wnt and Hedgehog signals that may tightly regulate the extent of neural stem/progenitor cell proliferation in the Xenopus retina.

  14. Treatment of digital ulcers in systemtic sclerosis with endothelin-1 receptor antagonist (bosentan

    Directory of Open Access Journals (Sweden)

    V. Grattagliano


    Full Text Available In systemic sclerosis (SSc occurrence of recurrent digital ulcers (DU is cause of pain and functional disability of hands. Treatment with vasodilator agents, such as calcium channel blockers, ACE inhibitors, prostanoids, has not shown to be an effective therapy. There is evidence that endotelin-1 (ET-1 is a key mediator in regulation of vascular tone and its enhanced production in SSc is believed to lead to vasoconstriction, vessel remodelling, local ischemia and ulcers of fingertips. Recently, an oral endothelin receptor antagonist, bosentan, has been proved to be effective in the treatment of SSc associated pulmonar arterial hypertension (PAH and to decrease the development of new DU in patients with SSc. In this study, we assessed the occurrence of new DU in eight patients with SSc associated PAH and one SSc patient with recurrent DU refractory to standard vasodilatation therapy. All patients received bosentan at dosage of 62.5 mg bid for 4 weeks and 125 mg bid thereafter for one year. All patients had 3-4 DU of hands at baseline and one patients had also ulcers at lower limbs. In seven out of nine patients we did not record the occurrence of new DU and we also observed a 50% reduction of existing DU, whereas new DU occurred only in two patients. These data suggest that ET-1 plays a key role in DU induction in SSc patients and that ET-1 inhibition by bosentan can be an effective therapeutic strategy.

  15. Interaction and modulation of two antagonistic cell wall enzymes of mycobacteria.

    Directory of Open Access Journals (Sweden)

    Erik C Hett

    Full Text Available Bacterial cell growth and division require coordinated cell wall hydrolysis and synthesis, allowing for the removal and expansion of cell wall material. Without proper coordination, unchecked hydrolysis can result in cell lysis. How these opposing activities are simultaneously regulated is poorly understood. In Mycobacterium tuberculosis, the resuscitation-promoting factor B (RpfB, a lytic transglycosylase, interacts and synergizes with Rpf-interacting protein A (RipA, an endopeptidase, to hydrolyze peptidoglycan. However, it remains unclear what governs this synergy and how it is coordinated with cell wall synthesis. Here we identify the bifunctional peptidoglycan-synthesizing enzyme, penicillin binding protein 1 (PBP1, as a RipA-interacting protein. PBP1, like RipA, localizes both at the poles and septa of dividing cells. Depletion of the ponA1 gene, encoding PBP1 in M. smegmatis, results in a severe growth defect and abnormally shaped cells, indicating that PBP1 is necessary for viability and cell wall stability. Finally, PBP1 inhibits the synergistic hydrolysis of peptidoglycan by the RipA-RpfB complex in vitro. These data reveal a post-translational mechanism for regulating cell wall hydrolysis and synthesis through protein-protein interactions between enzymes with antagonistic functions.

  16. Antagonistic action of Bacillus subtilis strain SG6 on Fusarium graminearum. (United States)

    Zhao, Yueju; Selvaraj, Jonathan Nimal; Xing, Fuguo; Zhou, Lu; Wang, Yan; Song, Huimin; Tan, Xinxin; Sun, Lichao; Sangare, Lancine; Folly, Yawa Minnie Elodie; Liu, Yang


    Fusarium graminearum causes Fusarium head blight (FHB), a devastating disease that leads to extensive yield and quality loss of wheat and barley. Bacteria isolated from wheat kernels and plant anthers were screened for antagonistic activity against F. graminearum. Based on its in vitro effectiveness, strain SG6 was selected for characterization and identified as Bacillus subtilis. B. subtilis SG6 exhibited a high antifungal effect on the mycelium growth, sporulation and DON production of F. graminearum with the inhibition rate of 87.9%, 95.6% and 100%, respectively. In order to gain insight into biological control effect in situ, we applied B. subtilis SG6 at anthesis through the soft dough stage of kernel development in field test. It was revealed that B. subtilis SG6 significantly reduced disease incidence (DI), FHB index and DON (P ≤ 0.05). Further, ultrastructural examination shows that B. subtilis SG6 strain induced stripping of F. graminearum hyphal surface by destroying the cellular structure. When hypha cell wall was damaged, the organelles and cytoplasm inside cell would exude, leading to cell death. The antifungal activity of SG6 could be associated with the coproduction of chitinase, fengycins and surfactins.

  17. Discovery of novel protease activated receptors 1 antagonists with potent antithrombotic activity in vivo. (United States)

    Perez, Michel; Lamothe, Marie; Maraval, Catherine; Mirabel, Etienne; Loubat, Chantal; Planty, Bruno; Horn, Clemens; Michaux, Julien; Marrot, Sebastien; Letienne, Robert; Pignier, Christophe; Bocquet, Arnaud; Nadal-Wollbold, Florence; Cussac, Didier; de Vries, Luc; Le Grand, Bruno


    Protease activated receptors (PARs) or thrombin receptors constitute a class of G-protein-coupled receptors (GPCRs) implicated in the activation of many physiological mechanisms. Thus, thrombin activates many cell types such as vascular smooth muscle cells, leukocytes, endothelial cells, and platelets via activation of these receptors. In humans, thrombin-induced platelet aggregation is mediated by one subtype of these receptors, termed PAR1. This article describes the discovery of new antagonists of these receptors and more specifically two compounds: 2-[5-oxo-5-(4-pyridin-2-ylpiperazin-1-yl)penta-1,3-dienyl]benzonitrile 36 (F 16618) and 3-(2-chlorophenyl)-1-[4-(4-fluorobenzyl)piperazin-1-yl]propenone 39 (F 16357), obtained after optimization. Both compounds are able to inhibit SFLLR-induced human platelet aggregation and display antithrombotic activity in an arteriovenous shunt model in the rat after iv or oral administration. Furthermore, these compounds are devoid of bleeding side effects often observed with other types of antiplatelet drugs, which constitutes a promising advantage for this new class of antithrombotic agents.

  18. The muscle relaxant thiocolchicoside is an antagonist of GABAA receptor function in the central nervous system. (United States)

    Carta, Mario; Murru, Luca; Botta, Paolo; Talani, Giuseppe; Sechi, GianPietro; De Riu, PierLuigi; Sanna, Enrico; Biggio, Giovanni


    Thiocolchicoside (TCC) is used clinically for its muscle relaxant, anti-inflammatory, and analgesic properties, and it has been shown to interact with gamma-aminobutyric acid (GABA) type A receptors (GABAARs) and strychnine-sensitive glycine receptors in the rat central nervous system. In contrast to a proposed agonistic action at these two types of inhibitory receptors, pharmacological evidence has shown that, under certain conditions, TCC manifests convulsant activity in animals and humans. We now show that the phasic and tonic GABAAR-mediated currents recorded from Purkinje cells and granule neurons, respectively, in parasagittal cerebellar slices from adult male rats were inhibited by TCC in a concentration-dependent manner. The median inhibitory concentrations of TCC for these effects were approximately 0.15 and approximately 0.9 microM, respectively. TCC did not potentiate GABABR-mediated currents in hippocampal slices, suggesting that its muscle relaxant action is not mediated by GABABRs. Intraperitoneal injection of TCC in rats either alone or in combination with negative modulators of GABAergic transmission revealed convulsant and proconvulsant actions of this drug. Our data, consistent with clinical observations of the epileptogenic effect of this compound, suggest that TCC is a potent competitive antagonist of GABAAR function.

  19. Identification of VDR Antagonists among Nuclear Receptor Ligands Using Virtual Screening

    Directory of Open Access Journals (Sweden)

    Kelly Teske


    Full Text Available Herein, we described the development of two virtual screens to identify new vitamin D receptor (VDR antagonists among nuclear receptor (NR ligands. Therefore, a database of 14330 nuclear receptor ligands and their NR affinities was assembled using the online available “Binding Database.” Two different virtual screens were carried out in conjunction with a reported VDR crystal structure applying a stringent and less stringent pharmacophore model to filter docked NR ligand conformations. The pharmacophore models were based on the spatial orientation of the hydroxyl functionalities of VDR's natural ligands 1,25(OH2D3 and 25(OH2D3. The first virtual screen identified 32 NR ligands with a calculated free energy of VDR binding of more than -6.0 kJ/mol. All but nordihydroguaiaretic acid (NDGA are VDR ligands, which inhibited the interaction between VDR and coactivator peptide SRC2-3 with an IC50 value of 15.8 μM. The second screen identified 162 NR ligands with a calculated free energy of VDR binding of more than -6.0 kJ/mol. More than half of these ligands were developed to bind VDR followed by ERα/β ligands (26%, TRα/β ligands (7%, and LxRα/β ligands (7%. The binding between VDR and ERα ligand H6036 as well as TRα/β ligand triiodothyronine and a homoserine analog thereof was confirmed by fluorescence polarization.

  20. Antagonistic action of Bacillus subtilis strain SG6 on Fusarium graminearum.

    Directory of Open Access Journals (Sweden)

    Yueju Zhao

    Full Text Available Fusarium graminearum causes Fusarium head blight (FHB, a devastating disease that leads to extensive yield and quality loss of wheat and barley. Bacteria isolated from wheat kernels and plant anthers were screened for antagonistic activity against F. graminearum. Based on its in vitro effectiveness, strain SG6 was selected for characterization and identified as Bacillus subtilis. B. subtilis SG6 exhibited a high antifungal effect on the mycelium growth, sporulation and DON production of F. graminearum with the inhibition rate of 87.9%, 95.6% and 100%, respectively. In order to gain insight into biological control effect in situ, we applied B. subtilis SG6 at anthesis through the soft dough stage of kernel development in field test. It was revealed that B. subtilis SG6 significantly reduced disease incidence (DI, FHB index and DON (P ≤ 0.05. Further, ultrastructural examination shows that B. subtilis SG6 strain induced stripping of F. graminearum hyphal surface by destroying the cellular structure. When hypha cell wall was damaged, the organelles and cytoplasm inside cell would exude, leading to cell death. The antifungal activity of SG6 could be associated with the coproduction of chitinase, fengycins and surfactins.

  1. Cyclic lipopeptide profile of three Bacillus subtilis strains; antagonists of Fusarium head blight. (United States)

    Dunlap, Christopher A; Schisler, David A; Price, Neil P; Vaughn, Steven F


    The objective of the study was to identify the lipopetides associated with three Bacillus subtilis strains. The strains are antagonists of Gibberella zeae, and have been shown to be effective in reducing Fusarium head blight in wheat. The lipopeptide profile of three B. subtilis strains (AS43.3, AS43.4, and OH131.1) was determined using mass spectroscopy. Strains AS43.3 and AS43.4 produced the anti-fungal lipopeptides from the iturin and fengycin family during the stationary growth phase. All three strains produced the lipopeptide surfactin at different growth times. Strain OH131.1 only produced surfactin under these conditions. The antifungal activity of the culture supernatant and individual lipopeptides was determined by the inhibition of G. zeae. Cell-free supernatant from strains AS43.3 and AS43.4 demonstrated strong antibiosis of G. zeae, while strain OH131.1 had no antibiosis activity. These results suggest a different mechanism of antagonism for strain OH131.1, relative to AS43.3 and AS43.4.

  2. Emerging role of orexin antagonists in insomnia therapeutics: An update on SORAs and DORAs. (United States)

    Kumar, Anil; Chanana, Priyanka; Choudhary, Supriti


    The pharmacological management of insomnia has lately become a challenge for researchers worldwide. As per the third International Classification of Sleep disorders (ICSD-3) insomnia can be defined as a state with repeated difficulty in sleep initiation, duration, consolidation, or quality that occurs despite adequate opportunity and circumstances for sleep, and results in some form of daytime impairment. The conventional treatments approved for management of insomnia were benzodiazepines (BZDs) (estazolam, quazepam, triazolam, flurazepam and temazepam) and non-BZDs, also known as z-drugs (zaleplon, zolpidem, and eszopiclone), tricyclic antidepressant (TCA) doxepin as well as melatonin agonists, e.g. ramelteon. But the potential of these agents to address sleep problems has been limited due to substantial side effects associated with them like hangover, dependence and tolerance, rebound insomnia, muscular atonia, inhibition of respiratory system, cognitive dysfunctions, and increased anxiety. Recently, orexin neuropeptides have been identified as regulators of transition between wakefulness and sleep and documented to aid an initial transitory effect towards wakefulness by activating cholinergic/monoaminergic neural pathways of the ascending arousal system. This has led to the development of orexin peptides and receptors, as possible therapeutic targets for the treatment of sleep disorders with the advantage of having lesser side effects as compared to conventional treatments. The present review focuses on the orexin peptides and receptors signifying their physiological profile as well as the development of orexin receptor antagonists as novel strategies in sleep medicine.

  3. Pharmacokinetic and pharmacodynamic interactions between almorexant, a dual orexin receptor antagonist, and desipramine. (United States)

    Cruz, Hans G; Hay, Justin L; Hoever, Petra; Alessi, Federica; te Beek, Erik T; van Gerven, Joop M A; Dingemanse, Jasper


    Almorexant is a dual orexin receptor antagonist (DORA) with sleep-enabling effects in humans. Insomnia is often associated with mental health problems, including depression. Hence, potential interactions with antidepressants deserve attention. Desipramine was selected as a model drug because it is mainly metabolized by CYP2D6, which is inhibited by almorexant in vitro. A single-center, randomized, placebo-controlled, two-way crossover study in 20 healthy male subjects was conducted to evaluate the pharmacokinetic and pharmacodynamic interactions between almorexant and desipramine. Almorexant 200mg or matching placebo (double-blind) was administered orally once daily in the morning for 10 days, and a single oral dose of 50mg desipramine (open-label) was administered on Day 5. Almorexant increased the exposure to desipramine 3.7-fold, suggesting that almorexant is a moderate inhibitor of desipramine metabolism through inhibition of CYP2D6. Conversely, desipramine showed no relevant effects on the pharmacokinetics of almorexant. Pharmacodynamic evaluations indicated that almorexant alone reduced visuomotor coordination, postural stability, and alertness, and slightly increased calmness. Desipramine induced a reduction in subjective alertness and an increase in pupil/iris ratio. Despite the increase in exposure to desipramine, almorexant and desipramine in combination showed the same pharmacodynamic profile as almorexant alone, except for prolonging reduced alertness and preventing the miotic effect of almorexant. Co-administration also prolonged the mydriatic effect of desipramine. Overall, repeated administration of almorexant alone or with single-dose desipramine was well tolerated. The lack of a relevant interaction with antidepressants, if confirmed for other DORAs, would be a key feature for a safer class of hypnotics.

  4. Effects of the estrogen receptor antagonist fulvestrant on F344 rat prolactinoma models. (United States)

    Cao, Lei; Gao, Hua; Gui, Songbai; Bai, Giwei; Lu, Runchun; Wang, Fei; Zhang, Yazhuo


    The relationship between estrogen and prolactinoma is well documented. But the anti-tumor effects of a pure estrogen receptor antagonist fulvestrant on prolactinomas, especially in vivo, and the possible mechanisms are still unclear. Therefore, the aim of this study was to evaluate the effects of fulvestrant and the involvement of the Wnt signaling pathway on rat prolactinoma models. Forty female F344 rat prolactinoma models were established by subcutaneous administration of 10 mg 17β-estradiol for 6 weeks. Rats were intramuscularly injected with fulvestrant (0, 0.5, 3, 20, 40 mg/kg), and tumor size, weight and serum prolactin (PRL) levels were evaluated before and after fulvestrant treatment at 3, 7 and 14 days. Expression of estrogen receptor α (ERα), β-catenin and Wnt inhibitory factor-1 (WIF-1) in prolactinomas was measured using quantitative PCR and western blotting, and methylation of the WIF-1 promoter was investigated using pyrosequencing. Tumor size, weight and serum PRL levels were inhibited in dose-dependent and time-dependent manners after fulvestrant treatments. β-catenin expression was downregulated but WIF-1 expression was upregulated following fulvestrant treatment. The methylation of the CpG site of the WIF-1 promoter was negatively correlated to the expression of WIF-1. In addition, the anti-cell proliferation of fulvestrant on GH3 cells was partly disrupted by Wnt signaling pathway agonist SB 216763. In conclusion, fulvestrant inhibited tumor proliferation and PRL secretion of prolactinomas via ERα, and the Wnt signaling pathway was involved in this anti-tumor effect. Therefore, fulvestrant may be a potential new drug for prolactinomas.

  5. N-methyl-D-aspartate antagonist activity of alpha- and beta-sulfallorphans. (United States)

    Shukla, V K; Lemaire, S


    Resolved equatorial (alpha) and axial (beta) forms of S-allylmorphinans, alpha-sulfallorphan and beta-sulfallorphan, were tested for their ability to compete with the binding of phencyclidine and sigma receptor ligands to mouse brain membranes and to antagonize N-methyl-D-aspartate (NMDA)-induced convulsions in mice. alpha- and beta-sulfallorphans displayed distinct binding affinities for phencyclidine and sigma sites, inhibiting the binding of [3H]-(5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten++ +-5, 10-imine ([3H]MK-801) with Ki values of 2.32 and 0.13 microM and that of [3H](+)-pentazocine with Ki values of 1.97 and 1.61 microM, respectively. Intracerebroventricular administration of these compounds in mice caused dose-dependent inhibitions of NMDA-induced convulsions, but did not affect convulsions induced by (R,S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), kainic acid and bicuculline. alpha- and beta-sulfallorphans blocked the convulsive activity of NMDA (1 nmol/mouse; intracerebroventricular) with ED50 values of 0.48 and 0.015 nmol/mouse, as compared with 0.55, 0.039 and 0.013 nmol/mouse for dextrorphan, MK-801 and (+/-)3-(2-carboxypiperazine-4yl)propyl-1-proprionic acid, respectively. The structurally related compound, dextrallorphan, significantly but less potently blocked NMDA-induced convulsions (ED60, 2.68 nmol/mouse). At the protective doses, alpha- and beta-sulfallorphans markedly reduced NMDA- and AMPA-induced mortality without inducing locomotion and falling behavior. These results indicate that alpha- and beta-sulfallorphans are potent and selective NMDA antagonists devoid of motor side effects at protective doses.

  6. Synergetic and Antagonistic Effects of Cadmium on Adsorption of Atrazine on Surficial Sediments

    Institute of Scientific and Technical Information of China (English)

    LI Yu; GAO Qian; WANG Xiao-li; DONG De-ming; WANG Ao


    Co-contamination of atrazine(AT) and cadmium(Cd) on the surficial sediments(SSs) and natural suface coating samples(NSCSs) was investigated via thermodynamic adsorption experiments.The results show that surface coatings have a stronger ability to adsorb AT owing to their higher active components compared with surficial sediments.Synergetic and antagonistic effects of Cd on the adsorption of AT were observed.Cd at a lower concentration(≤4.0 mg/L) in the solid/liquid phase enhanced AT adsorption onto the surficiai sediments(surface coatings),while the adsorption of AT would be inhibited at a Cd concentration of more than 8.0 mg/L:AT coordinates strongly to Cd,and AT-Cd complexes seem to be more strongly adsorbed on sediments than AT alone,and at the adsorption of AT can take place on the sites where Cd has been previously adsorbed and Cd acts as a bridge for the interaction between sediments and AT.With the increase of Cd concentration,the superfluous Cd may hold much more adsorption sites and thus inhibits the adsorption of AT.Meanwhile,the effects of co-existed AT on Cd adsorption on SSs(NSCSs)were insignificant since Cd has a stronger competitive ability to be absorbed on SSs(NSCSs).The present study could be useful in predicting interactions of the metal ions with herbicides and potentially aid the design of remediation strategies for contaminated sediments and groundwater.

  7. Actions of dopamine antagonists on stimulated striatal and limbic dopamine release: an in vivo voltammetric study.


    Stamford, J. A.; Kruk, Z L; Millar, J.


    1. Fast cyclic voltammetry at carbon fibre microelectrodes was used to study the effects of several dopamine antagonists upon stimulated dopamine release in the rat striatum and nucleus accumbens. 2. In both nuclei, stimulated dopamine release was increased by D2-receptor-selective and mixed D1/D2-receptor antagonists. The D1-selective antagonist SCH 23390 had no effect. 3. Striatal and limbic dopamine release were elevated by cis- but not trans-flupenthixol. 4. The 'atypical' neuroleptics (c...

  8. 大豆疫霉拮抗菌株的筛选与鉴定%Screening and Identification of Antagonistic Strain against Phytophthora sojae

    Institute of Scientific and Technical Information of China (English)

    付红梅; 李森; 檀根甲; 王子迎; 赵平生


    [ Objective] The paper was to .screen the antagonistic strain against Phytophthora sojae with biocontrol potential, and provide basis for searching control measures and designing new control strategies against P. sojae. [ Method] The rhizosphere soil of soybean was collected from three different places in Heilongiang Province, and various soil microorganisms were isolated. Dual culture method was used to screen the microorganism with antagonistic effect against P. sojae. On this basis, the growth inhibition rate of the microorganism with stronger antagonistic effect against P. sojae was determined, and its control effect against P. sojae was also measured. [ Result ] A strain of bacterium with relatively good antagonistic effect was isolated from soil, and named as strain B048. Dual test showed that the growth inhibition rate of antagonistic bacterium B048 against P. sojae reached 97.5%. Antagonistic endurance tests showed that the width of inhibition zone was still 20.0 mm after dual culture with P. sojae for 21 d. In potting experiment, the control effect of B048 against P. sojae was 100%. The antagonistic bacterium was primarily identified to be Bacillus pumilus through morphology and 16S rDNA sequence analysis. [ Conclusion] The antagonistic bacterium B048 had good prospect to be developed as the biocontrol bacterium against P. sojae.%[目的]筛选具有生防潜力的大豆疫霉拮抗菌,为寻找病害防控措施、设计新的疫病控制策略提供基础.[方法]从黑龙江省3个不同地区采集大豆根围土壤样本并分离各类土壤微生物,采用对峙培养法筛选出对大豆疫霉有拮抗作用的微生物,并在此基础上测定拮抗力较强微生物对大豆疫霉菌的生长抑制率及其对大豆疫病的控制作用.[结果]从土壤中分离得到1株拮抗效果相对较好的细菌,命名为B048菌株.对峙试验结果显示,拮抗细菌B048菌株对大豆疫霉的生长抑制率达97.5%;拮抗持久力测定显示,

  9. r-bPiDI, an α6β2* Nicotinic Receptor Antagonist, Decreases Nicotine-Evoked Dopamine Release and Nicotine Reinforcement (United States)

    Beckmann, Joshua S.; Meyer, Andrew C.; Pivavarchyk, M.; Horton, David B.; Zheng, Guangrong; Smith, Andrew M.; Wooters, Thomas E.; McIntosh, J. Michael; Crooks, Peter A.; Bardo, Michael T.


    α6β2* nicotinic acetylcholine receptors (nACh Rs) expressed by dopaminergic neurons mediate nicotine-evoked dopamine (DA) release and nicotine reinforcement. α6β2* antagonists inhibit these effects of nicotine, such that α6β2* receptors serve as therapeutic targets for nicotine addiction. The present research assessed the neuropharmacology of 1,10-bis(3-methyl-5,6-dihydropyridin-1(2H)-yl)decane (r-bPiDI), a novel small-molecule, tertiary amino analog of its parent compound, N,N-decane-1,10-diyl-bis-3-picolinium diiodide (bPiDI). bPiDI was previously shown to inhibit both nicotine-evoked DA release and the reinforcing effects of nicotine. In the current study, r-bPiDI inhibition of [3H]nicotine and [3H]methyllyca-conitine binding sites was evaluated to assess interaction with the recognition binding sites on α4β2* and α7* nAChRs, respectively. Further, r-bPiDI inhibition of nicotine-evoked DA release in vitro in the absence and presence of α-conotoxin MII and following chronic in vivo nicotine administration were determined. The ability of r-bPiDI to decrease nicotine self-administration and food-maintained responding was also assessed. Results show that r-bPiDI did not inhibit [3H]nicotine or [3H]methylly-caconitine binding, but potently (IC50 = 37.5 nM) inhibited nicotine-evoked DA release from superfused striatal slices obtained from either drug naïve rats or from those repeatedly treated with nicotine. r-bPiDI inhibition of nicotine-evoked DA release was not different in the absence or presence of α-conotoxin MII, indicating that r-bPiDI acts as a potent, selective α6β2* nAChR antagonist. Acute systemic administration of r-bPiDI specifically decreased nicotine self-administration by 75 %, and did not alter food-maintained responding, demonstrating greater specificity relative to bPiDI and bPiDDB, as well as the tertiary amino analog r-bPiDDB. The current work describes the discovery of r-bPiDI, a tertiary amino, α-conotoxin MII-like small molecule

  10. Synthesis and Dual Histamine H1 and H2 Receptor Antagonist Activity of Cyanoguanidine Derivatives



    Premedication with a combination of histamine H1 receptor (H1R) and H2 receptor (H2R) antagonists has been suggested as a prophylactic principle, for instance, in anaesthesia and surgery. Aiming at pharmacological hybrids combining H1R and H2R antagonistic activity, a series of cyanoguanidines 14–35 was synthesized by linking mepyramine-type H1R antagonist substructures with roxatidine-, tiotidine-, or ranitidine-type H2R antagonist moieties. N-desmethylmepyramine was connected via a poly-met...

  11. Effect of YM218, a nonpeptide vasopressin V(1A) receptor-selective antagonist, on rat mesangial cell hyperplasia and hypertrophy. (United States)

    Tahara, Atsuo; Tsukada, Junko; Tomura, Yuichi; Suzuki, Takeshi; Yatsu, Takeyuki; Shibasaki, Masayuki


    Mesangial cell growth constitutes a key feature of progressive glomerular injury. Vasopressin (AVP), a potent peptide vasoconstrictor, acts on mesangial cells through the V(1A) receptors, inducing contraction and cell proliferation. This study examined the effects of YM218, a nonpeptide AVP V(1A) receptor-selective antagonist, on the mitogenic and hypertrophic effects of AVP in rat mesangial cells. When added to mesangial cells whose growth was arrested, AVP concentration-dependently induced hyperplasia and hypertrophy. YM218 potently prevented AVP-induced hyperplasia and hypertrophy of these cells. Furthermore, AVP stimulated endothelin (ET)-1 secretion from mesangial cells in a concentration-dependent manner and this effect was potently inhibited by YM218. ET-1 also induced hyperplasia and hypertrophy in mesangial cells and this effect was completely abolished by ET(A) receptor-selective antagonist YM598. In addition, AVP-induced hyperplasia and hypertrophy were partly inhibited by YM598. These results suggest that AVP may modulate mesangial cell growth not only by its direct action but also through the stimulation of ET-1 secretion. YM218 displays high potency in inhibiting the AVP-induced physiologic responses of mesangial cells via the V(1A) receptors and is a potent pharmacologic probe for investigating the physiologic and pathophysiologic roles of AVP in several renal diseases.

  12. N-terminal mono-PEGylation of growth hormone antagonist: correlation of PEG size and pharmacodynamic behavior. (United States)

    Wu, Ling; Ho, Sa V; Wang, Wei; Gao, Jianping; Zhang, Guifeng; Su, Zhiguo; Hu, Tao


    Growth hormone antagonist (GHA), an analog of growth hormone (GH), can inhibit GH action and treat acromegaly. However, GHA suffers from a short plasma half-life of 15-20 min that has limited its clinical application. PEGylation, conjugation with polyethylene glycol (PEG), can increase the plasma half-life of GHA. Single PEG attachment (mono-PEGylation) at N-terminus of GHA has the advantages of product homogeneity and minimization of the bioactivity loss. Conjugation of large PEG molecule may increase the plasma half-life but could potentially decrease the bioactivity of GHA, due to the steric shielding effect of PEG. Thus, N-terminal mono-PEGylation of GHA with 20 kDa and 40 kDa PEG were used to look for a balance of the two competing factors. Sedimentation velocity analysis suggested that 40 kDa PEG was more efficient than 20 kDa PEG to elongate the molecular shape of the conjugate. As reflected by marginal suppression of insulin-like growth factor I (IGF-I), GHA conjugated with 40 kDa PEG was statistically indistinguishable from the saline solution that could not inhibit GH action. In contrast, GHA conjugated with 20kDa PEG can apparently inhibit GH action, as reflected by IGF-I suppression of 30-43%. Thus, our work demonstrated the effective therapeutic potency of N-terminally mono-PEGylated GHA.

  13. Hedgehog signaling antagonist promotes regression of both liver fibrosis and hepatocellular carcinoma in a murine model of primary liver cancer.

    Directory of Open Access Journals (Sweden)

    George M Philips

    Full Text Available OBJECTIVE: Chronic fibrosing liver injury is a major risk factor for hepatocarcinogenesis in humans. Mice with targeted deletion of Mdr2 (the murine ortholog of MDR3 develop chronic fibrosing liver injury. Hepatocellular carcinoma (HCC emerges spontaneously in such mice by 50-60 weeks of age, providing a model of fibrosis-associated hepatocarcinogenesis. We used Mdr2(-/- mice to investigate the hypothesis that activation of the hedgehog (Hh signaling pathway promotes development of both liver fibrosis and HCC. METHODS: Hepatic injury and fibrosis, Hh pathway activation, and liver progenitor populations were compared in Mdr2(-/- mice and age-matched wild type controls. A dose finding experiment with the Hh signaling antagonist GDC-0449 was performed to optimize Hh pathway inhibition. Mice were then treated with GDC-0449 or vehicle for 9 days, and effects on liver fibrosis and tumor burden were assessed by immunohistochemistry, qRT-PCR, Western blot, and magnetic resonance imaging. RESULTS: Unlike controls, Mdr2(-/- mice consistently expressed Hh ligands and progressively accumulated Hh-responsive liver myofibroblasts and progenitors with age. Treatment of aged Mdr2-deficient mice with GDC-0449 significantly inhibited hepatic Hh activity, decreased liver myofibroblasts and progenitors, reduced liver fibrosis, promoted regression of intra-hepatic HCCs, and decreased the number of metastatic HCC without increasing mortality. CONCLUSIONS: Hh pathway activation promotes liver fibrosis and hepatocarcinogenesis, and inhibiting Hh signaling safely reverses both processes even when fibrosis and HCC are advanced.

  14. Kynurenic acid as an antagonist of α7 nicotinic acetylcholine receptors in the brain: facts and challenges. (United States)

    Albuquerque, Edson X; Schwarcz, Robert


    Kynurenic acid (KYNA), a major tryptophan metabolite, is a glutamate receptor antagonist, which is also reported to inhibit α7 nicotinic acetylcholine receptors (α7nAChRs). Due to variations in experimental approaches, controversy has arisen regarding the ability of KYNA to directly influence α7nAChR function. Here we summarize current concepts of KYNA neurobiology and review evidence pertaining to the proposed role of KYNA as an endogenous modulator of α7nAChRs and synaptic transmission. As dysfunction of α7nAChRs plays a major role in the pathophysiology of central nervous system disorders, elucidation of KYNA's action on this receptor subtype has significant therapeutic implications.

  15. Integrated effect of microbial antagonist, organic amendment and fungicide in controlling seedling mortality (Rhizoctonia solani) and improving yield in pea (Pisum sativum L.). (United States)

    Akhter, Wasira; Bhuiyan, Mohamed Khurshed Alam; Sultana, Farjana; Hossain, Mohamed Motaher


    The study evaluated the comparative performance of a few microbial antagonists, organic amendments and fungicides and their integration for the management of seedling mortality (Rhizoctonia solani Kühn) and yield improvement in pea (Pisum sativum L.). Before setting the experiment in field microplots, a series of in vitro and in vivo experiments were conducted to select a virulent isolate of R. solani, an effective antagonistic isolate of Trichoderma harzianum, a fungitoxic organic amendment and an appropriate fungicide. A greenhouse pathogenicity test compared differences in seedling mortality in pea inoculated by four isolates of R. solani and identified the isolate RS10 as the most virulent one. Among the 20 isolates screened in dual culture assay on PDA, T. harzianum isolate T-3 was found to show the highest (77.22%) inhibition of the radial growth of R. solani. A complete inhibition (100.00%) of colony growth of R. solani was observed when fungicide Bavistin 50 WP and Provax-200 at the rate of 100 and 250 ppm, respectively, were used, while Provax-200 was found to be highly compatible with T. harzianum. Mustard oilcake gave maximum inhibition (60.28%) of the radial growth of R. solani at all ratios, followed by sesame oilcake and tea waste. Integration of soil treatment with T. harzianum isolate T-3 and mustard oilcake and seed treatment with Provax-200 appeared to be significantly superior in reducing seedling mortality and improving seed yield in pea in comparison to any single or dual application of them in the experimental field. The research results will help growers develop integrated disease management strategies for the control of Rhizoctonia disease in pea. The research results show the need for an integrating selective microbial antagonist, organic amendment and fungicide to achieve appropriate management of seedling mortality (R. solani) and increase of seed yield in pea.

  16. Antagonistic Effect of Gut Bacteria in the Hybrid Carniolan Honey Bee, Apis Mellifera Carnica, Against Ascosphaera Apis, the Causal Organism of Chalkbrood Disease

    Directory of Open Access Journals (Sweden)

    Omar Mohamed O. M.


    Full Text Available The objective of this study was to isolate and characterize bacterial strains associated with the gut of the hybrid Carniolan honey bee, Apis mellifera carnica, and to determine their in vitro and in vivo potential against Ascosphaera apis, the causal organism of chalkbrood disease, with the purpose of exploring feasible biological control. Six bacterial strains were isolated from healthy worker honey bees by culture-dependent methods. Six fungal strains (A3, A4, A7, A8, A9, and A15 of A. apis were isolated from larvae suffering from chalkbrood disease on Yeast-Glucose-Starch agar (YGPSA medium. All bacteria were identified by a combination of morphology, Gram stain, and 16S rRNA sequence analysis, and fungal strains were identified by morphology and 5.8S rRNA. In vitro and in vivo inhibition assays were carried out to determine the ability of bacterial isolates to inhibit A. apis, the causal agent of chalkbrood disease. The analysis of 16S rRNA sequences revealed that four bacterial strains (B2, B4, B10, and B100 belong to Bacillus subtilis species, and two strains (P1 and P5 belong to Pseudomonas fluorescence. Significant differences in antagonistic activity of all bacterial strains were observed. B. subtilis isolate B2 showed the highest antagonistic activity, as measured by the inhibition zone against A. apis, followed by the P1 strain of P. fluorescence. SEM analysis also supports the antagonistic activity of these bacteria against A. apis. This study provides a theoretical basis for biological control of honey bee chalkbrood disease.

  17. Sepsis Strengthens Antagonistic Actions of Neostigmine on Rocuronium in a Rat Model of Cecal Ligation and Puncture

    Institute of Scientific and Technical Information of China (English)

    Jin Wu; Tian Jin; Hong Wang; Shi-Tong Li


    Background:The antagonistic actions of anticholinesterase drugs on non-depolarizing muscle relaxants are theoretically related to the activity ofacetylcholinesterase (AChE) in the neuromuscular junction (NMJ).However,till date the changes of AChE activity in the NMJ during sepsis have not been directly investigated.We aimed to investigate the effects of sepsis on the antagonistic actions ofneostigmine on rocuronium (Roc) and the underlying changes of AChE activity in the NMJ in a rat model of cecal ligation and puncture (CLP).Methods:A total of 28 male adult Sprague-Dawley rats were randomized to undergo a sham surgery (the sham group,n =12) or CLP (the septic group,n =16).After 24 h,the time-response curves of the antagonistic actions of 0.1 or 0.5 μmol/L of neostigmine on Roc (10 μmol/L)-depressed diaphragm twitch tension were measured.Meanwhile,the activity of AChE in the NMJ was detected using a modified Karnovsky and Roots method.The mRNA levels of the primary transcript and the type T transcript of AChE (AChET) in the diaphragm were determined by real-time reverse transcription-polymerase chain reaction.Results:Four of 16 rats in the septic group died within 24 h.The time-response curves of both two concentrations ofneostigmine in the septic group showed significant upward shifts from those in the sham group (P < 0.001 for 0.1 μmol/L;P =0.009 for 0.5 μmol/L).Meanwhile,the average optical density of AChE in the NMJ in the septic group was significantly lower than that in the sham group (0.517 ± 0.045 vs.1.047 ± 0.087,P < 0.001).The AChE and AChET mRNA expression levels in the septic group were significantly lower than those in the sham group (P =0.002 for AChE;P =0.00l for AChET).Conclusions:Sepsis strengthened the antagonistic actions ofneostigmine on Roc-depressed twitch tension of the diaphragm by inhibiting the activity of AChE in the NMJ.The reduced content of AChE might be one of the possible causes of the decreased AChE activity in the NMJ.

  18. Misoprostol inhibits gastric mucosal release of endogenous prostaglandin E2 and thromboxane B2 in healthy volunteers

    DEFF Research Database (Denmark)

    Mertz-Nielsen, A; Eskerod, O; Bukhave, K;


    antagonists in preventing ulcer relapse. It could be that prostaglandin analogues inhibit gastric mucosal synthesis or release of endogenous eicosanoids, thereby abrogating their own effects. This study, therefore, examined how a single therapeutic dose (200 micrograms) of misoprostol, a synthetic analogue....... These data show that misoprostol inhibits gastric mucosal synthesis of prostanoids. Decreased concentrations, or even a changed profile, of native eicosanoids modulating the release of inflammatory mediators from immune cells might explain why prostaglandin analogues have a comparatively poor clinical...

  19. Meta-diamide insecticides acting on distinct sites of RDL GABA receptor from those for conventional noncompetitive antagonists. (United States)

    Nakao, Toshifumi; Banba, Shinich; Nomura, Michikazu; Hirase, Kangetsu


    The RDL GABA receptor is an attractive target of insecticides. Here we demonstrate that meta-diamides [3-benzamido-N-(4-(perfluoropropan-2-yl)phenyl)benzamides] are a distinct class of RDL GABA receptor antagonists showing high insecticidal activity against Spodoptera litura. We also suggest that the mode of action of the meta-diamides is distinct from that of conventional noncompetitive antagonists (NCAs), such as fipronil, picrotoxin, lindane, dieldrin, and α-endosulfan. Using a membrane potential assay, we examined the effects of the meta-diamide 3-benzamido-N-(2-bromo-4-(perfluoropropan-2-yl)-6-(trifluoromethyl)phenyl)-2-fluorobenzamide (meta-diamide 7) and NCAs on mutant Drosophila RDL GABA receptors expressed in Drosophila Mel-2 cells. NCAs had little or no inhibitory activity against at least one of the three mutant receptors (A2'S, A2'G, and A2'N), which were reported to confer resistance to NCAs. In contrast, meta-diamide 7 inhibited all three A2' mutant receptors, at levels comparable to its activity with the wild-type receptor. Furthermore, the A2'S·T6'V mutation almost abolished the inhibitory effects of all NCAs. However, meta-diamide 7 inhibited the A2'S・T6'S mutant receptor at the same level as its activity with the wild-type receptor. In contrast, a G336M mutation in the third transmembrane domain of the RDL GABA receptor abolished the inhibitory activities of meta-diamide 7, although the G336M mutation had little effect on the inhibitory activities of conventional NCAs. Molecular modeling studies also suggested that the binding site of meta-diamides was different from those of NCAs. Meta-diamide insecticides are expected to be prominent insecticides effective against A2' mutant RDL GABA receptors with a different mode of action.

  20. In vitro and in vivo pharmacological characterization of BIIL 284, a novel and potent leukotriene B(4) receptor antagonist. (United States)

    Birke, F W; Meade, C J; Anderskewitz, R; Speck, G A; Jennewein, H M


    BIIL 284 is a new LTB(4) receptor antagonist. It is a prodrug and has negligible binding to the LTB(4) receptor. However, ubiquitous esterases metabolize BIIL 284 to the active metabolites BIIL 260 and BIIL 315, the glucuronidated form of BIIL 260. Both metabolites have high affinity to the LTB(4) receptor on isolated human neutrophil cell membranes with K(i) values of 1.7 and 1.9 nM, respectively. On vital human neutrophilic granulocytes K(i) was around 1 nM. BIIL 260 and BIIL 315 interact with the LTB(4) receptor in a saturable, reversible, and competitive manner. BIIL 260 and its glucuronide BIIL 315 also potently inhibited LTB(4)-induced intracellular Ca(2+) release in human neutrophils (IC(50) values of 0.82 and 0.75 nM, respectively) as measured with Fura-2. High efficacy of BIIL 284 has been demonstrated in various in vivo models. BIIL 284 inhibited LTB(4)-induced mouse ear inflammation with ED(50) = 0.008 mg/kg p.o., LTB(4)-induced transdermal chemotaxis in guinea pigs with ED(50) = 0.03 mg/kg p.o., LTB(4)-induced neutropenia in various species (monkey: ED(50) = 0.004 mg/kg p.o.), and LTB(4)-induced Mac1-expression in monkeys (ED(50) = 0.05 mg/kg p.o. in Tylose). Full blockade of LTB(4) receptors over 24 h was achieved by 0.3 mg/kg BIIL 284 after single oral dose as measured by LTB(4)-induced neutropenia or Mac1-expression in the monkey model. BIIL 284 is an unusually potent and long-acting orally active LTB(4) antagonist, and is therefore under clinical development as a novel anti-inflammatory principle.

  1. Clinical experience in Europe with uroselective alpha1-antagonists. (United States)

    Debruyne, F M; Van der Poel, H G


    alpha1-Adrenoreceptors are thought to be involved in prostate smooth muscle contractions and could hence play a role in the dynamic component of intravesical obstruction associated with symptomatic BPH. Consequently, since the mid-eighties alpha receptor blocking agents have been used for the treatment of BPH. Non-selective alpha blockers are usually associated with systemic side-effects which resulted in an exclusion or withdrawal of many patients from this form of treatment. With the availability of so-called uroselective alpha blockers the management picture has changed since it was anticipated that these compounds cause lesser side-effects with at least the same, or even better, efficacy. Comparative clinical studies are essential for determining the eventual advantages of the uroselective alpha1-antagonists and a large number of such studies have been performed worldwide studying the various available compounds. European studies with terazosin showed clear superiority of the drug over the placebo while causing only limited side-effects. Various other studies using alpha-blocking agents such as doxazosin, tamsulosin and alfuzosin yielded identical results. Especially with tamsulosin and alfuzosin, the side-effects were comparable with those encountered in the placebo group. About 7% of the patients using tamsulosin experienced retrograde ejaculation in one study which did not occur in the alfuzosin studies. Important studies in Europe have also investigated the value of a combination of an alpha blocker with a 5alpha-reductase inhibitor. Comparable studies in which both alfuzosin and doxazosin were combined with the 5alpha-reductase inhibitor Proscar have shown that a combination is not superior to a blocker monotherapy and especially in the ALFIN study the results show that alfuzosin monotherapy is superior to Proscar in the management of symptomatic BPH. European studies have evaluated Quality of Life, sexuality as well as socio-economical outcome of the

  2. Histamine in the locus coeruleus promotes descending noradrenergic inhibition of neuropathic hypersensitivity. (United States)

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


    Among brain structures receiving efferent projections from the histaminergic tuberomammillary nucleus is the pontine locus coeruleus (LC) involved in descending noradrenergic control of pain. Here we studied whether histamine in the LC is involved in descending regulation of neuropathic hypersensitivity. Peripheral neuropathy was induced by unilateral spinal nerve ligation in the rat with a chronic intracerebral and intrathecal catheter for drug administrations. Mechanical hypersensitivity in the injured limb was assessed by monofilaments. Heat nociception was assessed by determining radiant heat-induced paw flick. Histamine in the LC produced a dose-related (1-10μg) mechanical antihypersensitivity effect (maximum effect at 15min and duration of effect 30min), without influence on heat nociception. Pretreatment of LC with zolantidine (histamine H2 receptor antagonist), but not with pyrilamine (histamine H1 receptor antagonist), and spinal administration of atipamezole (an α2-adrenoceptor antagonist), prazosine (an α1-adrenoceptor antagonist) or bicuculline (a GABAA receptor antagonist) attenuated the antihypersensitivity effect of histamine. The histamine-induced antihypersensitivity effect was also reduced by pretreatment of LC with fadolmidine, an α2-adrenoceptor agonist inducing autoinhibition of noradrenergic cell bodies. Zolantidine or pyrilamine alone in the LC failed to influence pain behavior, while A-960656 (histamine H3 receptor antagonist) suppressed hypersensitivity. A plausible explanation for these findings is that histamine, due to excitatory action mediated by the histamine H2 receptor on noradrenergic cell bodies, promotes descending spinal α