In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli

International Nuclear Information System (INIS)

Chatterjee, A.; Bhattacharya, A.K.

1988-01-01

The incorporation of [ 14 C]adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with 60 Co γ-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of γ-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after high doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m -2 ) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as γ-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells. (author)

In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli.

Science.gov (United States)

Chatterjee, A; Bhattacharya, A K

1988-06-01

The incorporation of [14C]adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with 60Co gamma-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of gamma-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after higher doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m-2) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as gamma-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells.

Cytosolic adenylate changes during exercise in prawn muscle

International Nuclear Information System (INIS)

Thebault, M.T.; Raffin, J.P.; Pichon, R.

1994-01-01

31 P NMR and biochemical analysis were used to assess the effect of heavy exercise on cytosolic adenylate levels in Palaemon serratus abdominal muscle. At rest, the MgATP level corresponded to 85.5% of the total ATP content. The cytosolic adenylate concentrations of the prawn muscle are considerably different from that of vertebrates. The percentage of ADP bound to myofilaments was lower in the prawn muscle. Consequently, the level of free cytosolic AMP was greatly higher (thirty fold higher) than in vertebrate muscle. During vigorous work, the concentration of MgATP dropped and the cytosolic AMP accumulated, while the cytosolic adenine nucleotide pool decreased significantly. The phosphorylation potential value and the ATP/ADP ratio, calculated from the cytosolic adenylate, dropped acutely during the whole period of muscular contractions. On the contrary, the adenylate energy charge calculated from the cytosolic adenylate decreased slightly. Therefore, even in muscle displaying no AMP deamination, the adenylate charge is stabilized during exercise by the dynamic changes between cytosolic and bound adenylate species. (author). 21 refs., 2 tabs

Hyperglycemia of Diabetic Rats Decreased by a Glucagon Receptor Antagonist

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Johnson, David G.; Ulichny Goebel, Camy; Hruby, Victor J.; Bregman, Marvin D.; Trivedi, Dev

1982-02-01

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.

Inhibition of [11C]mirtazapine binding by alpha2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain

DEFF Research Database (Denmark)

Smith, Donald F; Dyve, Suzan; Minuzzi, Luciano

2006-01-01

Inhibition of [11C]mirtazapine binding by alpha2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain......Inhibition of [11C]mirtazapine binding by alpha2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain...

Adenylate Cyclase Toxin Subverts Phagocyte Function by RhoA Inhibition and Unproductive Ruffling

Czech Academy of Sciences Publication Activity Database

Kamanová, Jana; Kofroňová, Olga; Mašín, Jiří; Genth, H.; Vojtová, Jana; Linhartová, Irena; Benada, Oldřich; Just, I.; Šebo, Peter

2008-01-01

Roč. 181, č. 8 (2008), s. 5587-5597 ISSN 0022-1767 R&D Projects: GA MŠk 1M0506; GA MŠk 2B06161; GA ČR GA310/08/0447 Grant - others:XE(XE) LSHB-CT-2003-503582 Institutional research plan: CEZ:AV0Z50200510 Keywords : bordetella * adenylate cyclase toxin * rhoa Subject RIV: EC - Immunology Impact factor: 6.000, year: 2008

Adenylate cyclase regulation in the spermatogenic cell plasma membrane: Modulating effects of TPA and TCDD

International Nuclear Information System (INIS)

Beebe, L.E.

1989-01-01

This research was designed to compare the effects of TPA, a phorbol ester, and TCDD in a spermatogenic cell population, a target of TCDD toxicity. Membrane-bound adenylate cyclase activity was used an index of membrane function, and was quantified by the amount of 32 P-cAMP formed from 32 P-ATP following chromatographic separation. Exposure to male germ cells in-vitro to TPA and TCDD followed by direct measurement of enzyme activity was used to investigate the potential of each agent to perturb membrane function. TPA and TCDD consistently inhibited adenylate cyclase activity at the levels of G s -catalytic unit coupling and hormone-receptor activation, as measured by the stimulation of enzyme activity by concomitant addition of forskolin and GTP and FSH and GTP, respectively. The effect on coupling required at least 60 minutes of exposure to TPA or TCDD. Concentration-response curves demonstrated a progressive desensitization with increasing TPA concentration, while TCDD exhibited consistent inhibition over the same concentration range

Dopamine inhibits somatolactin gene expression in tilapia pituitary cells through the dopamine D2 receptors.

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Jiang, Quan; Lian, Anji; He, Qi

2016-07-01

Dopamine (DA) is an important neurotransmitter in the central nervous system of vertebrates and possesses key hypophysiotropic functions. Early studies have shown that DA has a potent inhibitory effect on somatolactin (SL) release in fish. However, the mechanisms responsible for DA inhibition of SL gene expression are largely unknown. To this end, tilapia DA type-1 (D1) and type-2 (D2) receptor transcripts were examined in the neurointermediate lobe (NIL) of the tilapia pituitary by real-time PCR. In tilapia, DA not only was effective in inhibiting SL mRNA levels in vivo and in vitro, but also could abolish pituitary adenylate cyclase-activating polypeptide (PACAP)- and salmon gonadotropin-releasing hormone (sGnRH)-stimulated SL gene expression at the pituitary level. In parallel studies, the specific D2 receptor agonists quinpirole and bromocriptine could mimic the DA-inhibited SL gene expression. Furthermore, the D2 receptor antagonists domperidone and (-)-sulpiride could abolish the SL response to DA or the D2 agonist quinpirole, whereas D1 receptor antagonists SCH23390 and SKF83566 were not effective in this respect. In primary cultures of tilapia NIL cells, D2 agonist quinpirole-inhibited cAMP production could be blocked by co-treatment with the D2 antagonist domperidone and the ability of forskolin to increase cAMP production was also inhibited by quinpirole. Using a pharmacological approach, the AC/cAMP pathway was shown to be involved in quinpirole-inhibited SL mRNA expression. These results provide evidence that DA can directly inhibit SL gene expression at the tilapia pituitary level via D2 receptor through the AC/cAMP-dependent mechanism. Copyright © 2016 Elsevier Inc. All rights reserved.

Kynurenic Acid Inhibits the Electrical Stimulation Induced Elevated Pituitary Adenylate Cyclase-Activating Polypeptide Expression in the TNC

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Tamás Körtési

2018-01-01

Full Text Available BackgroundMigraine is a primary headache of imprecisely known mechanism, but activation of the trigeminovascular system (TS appears to be essential during the attack. Intensive research has recently focused on pituitary adenylate cyclase-activating polypeptide (PACAP and the kynurenine systems as potential pathogenic factors.AimWe investigated the link between these important mediators and the effects of kynurenic acid (KYNA and its synthetic analog (KYNA-a on PACAP expression in the rat trigeminal nucleus caudalis (TNC in a TS stimulation model related to migraine mechanisms.MethodsAdult male Sprague-Dawley rats were pretreated with KYNA, KYNA-a, the NMDA receptor antagonist MK-801, or saline (vehicle. Next, the trigeminal ganglion (TRG was electrically stimulated, the animals were transcardially perfused following 180 min, and the TNC was removed. In the TNC samples, 38 amino acid form of PACAP (PACAP1–38-like radioimmunoactivity was measured by radioimmunoassay, the relative optical density of preproPACAP was assessed by Western blot analysis, and PACAP1–38 mRNA was detected by real-time PCR.Results and conclusionElectrical TRG stimulation resulted in significant increases of PACAP1–38-LI, preproPACAP, and PACAP1–38 mRNA in the TNC. These increases were prevented by the pretreatments with KYNA, KYNA-a, and MK-801. This is the first study to provide evidence for a direct link between PACAP and the kynurenine system during TS activation.

Luteinizing hormone-stimulated pituitary adenylate cyclase-activating polypeptide system and its role in progesterone production in human luteinized granulosa cells.

Science.gov (United States)

Park, Hyun-Jeong; Choi, Bum-Chae; Song, Sang-Jin; Lee, Dong-Sik; Roh, Jaesook; Chun, Sang-Young

2010-01-01

The present study examined the gonadotropin regulation of pituitary adenylate cyclase-activating polypeptide (PACAP) and PACAP type I receptor (PAC(1)-R) expression, and its role in progesterone production in the human luteinized granulosa cells. The stimulation of both PACAP and PAC(1)-R mRNA levels by LH was detected using a competitive reverse transcription-polymerase chain reaction (RT-PCR). PACAP transcript was stimulated by LH reaching maximum levels at 12 hours in a dose dependent manner. LH treatment also stimulated PAC(1)-R mRNA levels within 24 hours. Addition of PACAP-38 (10(-7) M) as well as LH significantly stimulated progesterone production during 48 hours culture. Furthermore, co-treatment with PACAP antagonist partially inhibited LH-stimulated progesterone production. Treatment with vasoactive intestinal peptide, however, did not affect progesterone production. Taken together, the present study demonstrates that LH causes a transient stimulation of PACAP and PAC(1)-R expression and that PACAP stimulates progesterone production in the human luteinized granulosa cells, suggesting a possible role of PACAP as a local ovarian regulator in luteinization.

Interactions of dopaminergic agonists and antagonists with dopaminergic D3 binding sites in rat striatum. Evidence that [3H]dopamine can label a high affinity agonist-binding state of the D1 dopamine receptor

International Nuclear Information System (INIS)

Leff, S.E.; Creese, I.

1985-01-01

The interactions of dopaminergic agonists and antagonists with 3 H-agonist labeled D3 dopaminergic binding sites of rat striatum have been characterized by radioligand-binding techniques. When the binding of [ 3 H]dopamine and [ 3 H]apomorphine to D2 dopamine receptors is blocked by the inclusion of D2 selective concentrations of unlabeled spiroperidol or domperidone, these ligands appear to label selectively the previously termed D3 binding site. Antagonist/[ 3 H]dopamine competition curves are of uniformly steep slope (nH . 1.0), suggesting the presence of a single D3 binding site. The relative potencies of antagonists to inhibit D3 specific [ 3 H]dopamine binding are significantly correlated with their potencies to block D1 dopamine receptors as measured by the inhibition of both dopamine-stimulated adenylate cyclase and [ 3 H]flupentixol-binding activities. The affinities of agonists to inhibit D3 specific [ 3 H]dopamine binding are also correlated with estimates of these agonists affinities for the high affinity binding component of agonist/[ 3 H]flupentixol competition curves. Both D3 specific [ 3 H] dopamine binding and the high affinity agonist-binding component of dopamine/[ 3 H]flupentixol competition curves show a similar sensitivity to guanine nucleotides. Taken together, these data strongly suggest that the D3 binding site is related to a high affinity agonist-binding state of the D1 dopamine receptor

A Simple Luminescent Adenylate-Cyclase Functional Assay for Evaluation of Bacillus anthracis Edema Factor Activity

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Ma’ayan Israeli

2016-08-01

Full Text Available Edema Factor (EF, the toxic sub-unit of the Bacillus anthracis Edema Toxin (ET is a calmodulin-dependent adenylate cyclase whose detrimental activity in the infected host results in severe edema. EF is therefore a major virulence factor of B. anthracis. We describe a simple, rapid and reliable functional adenylate-cyclase assay based on inhibition of a luciferase-mediated luminescence reaction. The assay exploits the efficient adenylate cyclase-mediated depletion of adenosine tri-phosphate (ATP, and the strict dependence on ATP of the light-emitting luciferase-catalyzed luciferin-conversion to oxyluciferin, which can be easily visualized. The assay exhibits a robust EF-dose response decrease in luminescence, which may be specifically reverted by anti-EF antibodies. The application of the assay is exemplified in: (a determining the presence of EF in B. anthracis cultures, or its absence in cultures of EF-defective strains; (b evaluating the anti-EF humoral response in experimental animals infected/vaccinated with B. anthracis; and (c rapid discrimination between EF producing and non-producing bacterial colonies. Furthermore, the assay may be amenable with high-throughput screening for EF inhibitory molecules.

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

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

2013-01-01

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.

GABAA receptor partial agonists and antagonists

DEFF Research Database (Denmark)

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

2015-01-01

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...... antagonists have been essential in defining the tonic current but both remaining issues concerning the GABAARs involved and the therapeutic possibilities of modulating tonic inhibition underline the need for GABAAR antagonists with improved selectivity....

Inhibition of Anaerobic Phosphate Release by Nitric Oxide in Activated Sludge

Science.gov (United States)

Van Niel, E. W. J.; Appeldoorn, K. J.; Zehnder, A. J. B.; Kortstee, G. J. J.

1998-01-01

Activated sludge not containing significant numbers of denitrifying, polyphosphate [poly(P)]-accumulating bacteria was grown in a fill-and-draw system and exposed to alternating anaerobic and aerobic periods. During the aerobic period, poly(P) accumulated up to 100 mg of P · g of (dry) weight. When portions of the sludge were incubated anaerobically in the presence of acetate, 80 to 90% of the intracellular poly(P) was degraded and released as orthophosphate. Degradation of poly(P) was mainly catalyzed by the concerted action of polyphosphate:AMP phosphotransferase and adenylate kinase, resulting in ATP formation. In the presence of 0.3 mM nitric oxide (NO) in the liquid-phase release of phosphate, uptake of acetate, formation of poly-β-hydroxybutyrate, utilization of glycogen, and formation of ATP were severely inhibited or completely abolished. In cell extracts of the sludge, adenylate kinase activity was completely inhibited by 0.15 mM NO. The nature of this inhibition was probably noncompetitive, similar to that with hog adenylate kinase. Activated sludge polyphosphate glucokinase was also completely inhibited by 0.15 mM NO. It is concluded that the inhibitory effect of NO on acetate-mediated phosphate release by the sludge used in this study is due to the inhibition of adenylate kinase in the phosphate-releasing organisms. The inhibitory effect of nitrate and nitrite on phosphate release is probably due to their conversion to NO. The lack of any inhibitory effect of NO on adenylate kinase of the poly(P)-accumulating Acinetobacter johnsonii 210A suggests that this type of organism is not involved in the enhanced biological phosphate removal by the sludges used. PMID:9687452

P2X1 Receptor Antagonists Inhibit HIV-1 Fusion by Blocking Virus-Coreceptor Interactions.

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Giroud, Charline; Marin, Mariana; Hammonds, Jason; Spearman, Paul; Melikyan, Gregory B

2015-09-01

HIV-1 Env glycoprotein-mediated fusion is initiated upon sequential binding of Env to CD4 and the coreceptor CXCR4 or CCR5. Whereas these interactions are thought to be necessary and sufficient to promote HIV-1 fusion, other host factors can modulate this process. Previous studies reported potent inhibition of HIV-1 fusion by selective P2X1 receptor antagonists, including NF279, and suggested that these receptors play a role in HIV-1 entry. Here we investigated the mechanism of antiviral activity of NF279 and found that this compound does not inhibit HIV-1 fusion by preventing the activation of P2X1 channels but effectively blocks the binding of the virus to CXCR4 or CCR5. The notion of an off-target effect of NF279 on HIV-1 fusion is supported by the lack of detectable expression of P2X1 receptors in cells used in fusion experiments and by the fact that the addition of ATP or the enzymatic depletion of ATP in culture medium does not modulate viral fusion. Importantly, NF279 fails to inhibit HIV-1 fusion with cell lines and primary macrophages when added at an intermediate stage downstream of Env-CD4-coreceptor engagement. Conversely, in the presence of NF279, HIV-1 fusion is arrested downstream of CD4 binding but prior to coreceptor engagement. NF279 also antagonizes the signaling function of CCR5, CXCR4, and another chemokine receptor, as evidenced by the suppression of calcium responses elicited by specific ligands and by recombinant gp120. Collectively, our results demonstrate that NF279 is a dual HIV-1 coreceptor inhibitor that interferes with the functional engagement of CCR5 and CXCR4 by Env. Inhibition of P2X receptor activity suppresses HIV-1 fusion and replication, suggesting that P2X signaling is involved in HIV-1 entry. However, mechanistic experiments conducted in this study imply that P2X1 receptor is not expressed in target cells or involved in viral fusion. Instead, we found that inhibition of HIV-1 fusion by a specific P2X1 receptor antagonist, NF

Effects of PTH and Ca2+ on renal adenyl cyclase

International Nuclear Information System (INIS)

Nielsen, S.T.; Neuman, W.F.

1978-01-01

The effects of calcium ion on the adenylate cyclase system was studied in isolated, renal basal-lateral plasma membranes of the rat. Bovine parathyroid hormone (bPTH) and a guanyl triphosphate analogue, Gpp(NH)p were used to stimulate cyclase activity. Under conditions of maximal stimulation, calcium ions inhibited cyclic adenosine monophosphate (cAMP) formation, the formation rate falling exponentially with the calcium concentration. Fifty percent inhibition of either bPTH- or Gpp(NH)p-stimulated activity was given by approximately 50 μM Ca 2+ . Also the Hill coefficient for the inhibition was close to unity in both cases. The concentration of bPTH giving half-maximal stimulation of cAMP formation (1.8 x 10 -8 M) was unchanged by the presence of calcium. These data suggest that calcium acts at some point other than the initial hormone-receptor interaction, presumably decreasing the catalytic efficiency of the enzymic moiety of the membrane complex

Monospecific antibody against Bordetella pertussis Adenylate Cyclase protects from Pertussis

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Yasmeen Faiz Kazi

2012-06-01

Full Text Available Objectives: Acellular pertussis vaccines has been largely accepted world-wide however, there are reports about limitedantibody response against these vaccines suggesting that multiple antigens should be included in acellular vaccinesto attain full protection. The aim of present study was to evaluate the role of Bordetella pertussis adenylate cyclase as aprotective antigen.Materials and methods: Highly mono-specific antibody against adenylate cyclase (AC was raised in rabbits usingnitrocellulose bound adenylate cyclase and the specificity was assessed by immuoblotting. B.pertussis 18-323, wasincubated with the mono-specific serum and without serum as a control. Mice were challenged intra-nasally and pathophysiolgicalresponses were recorded.Results: The production of B.pertussis adenylate cyclase monospecific antibody that successfully recognized on immunoblotand gave protection against fatality (p< 0.01 and lung consolidation (p <0.01. Mouse weight gain showedsignificant difference (p< 0.05.Conclusion: These preliminary results highlight the role of the B.pertussis adenylate cyclase as a potential pertussisvaccine candidate. B.pertussis AC exhibited significant protection against pertussis in murine model. J Microbiol InfectDis 2012; 2(2: 36-43Key words: Pertussis; monospecific; antibody; passive-protection

The central regulation of plant physiology by adenylates.

Science.gov (United States)

Geigenberger, Peter; Riewe, David; Fernie, Alisdair R

2010-02-01

There have been many recent developments concerning the metabolic, transport and signalling functions of adenylates in plants, suggesting new roles for these compounds as central regulators of plant physiology. For example, altering the expression levels of enzymes involved in the equilibration, salvaging, synthesis and transport of adenylates leads to perturbations in storage, growth and stress responses, implying a role for adenylates as important signals. Furthermore, sensing of the internal energy status involves SNF1-related kinases, which control the expression and phosphorylation of key metabolic enzymes. ATP also acts as an apoplastic signalling molecule to control cell growth and pathogen responses. These new results could shed light on the emerging question of whether energy homeostasis in plant cells differs from mechanisms found in microbes and mammals. Copyright 2009 Elsevier Ltd. All rights reserved.

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

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Tiong Cheng Sia

2013-08-01

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.

[Adenylate cyclase from rabbit heart: substrate binding site].

Science.gov (United States)

Perfil'eva, E A; Khropov, Iu V; Khachatrian, L; Bulargina, T V; Baranova, L A

1981-08-01

The effects of 17 ATP analogs on the solubilized rabbit heart adenylate cyclase were studied. The triphosphate chain, position 8 of the adenine base and the ribose residue of the ATP molecule were modified. Despite the presence of the alkylating groups in two former types of the analogs tested, no covalent blocking of the active site of the enzyme was observed. Most of the compounds appeared to be competitive reversible inhibitors. The kinetic data confirmed the importance of the triphosphate chain for substrate binding in the active site of adenylate cyclase. (Formula: See Text) The inhibitors with different substituents in position 8 of the adenine base had a low affinity for the enzyme. The possible orientation of the triphosphate chain and the advantages of anti-conformation of the ATP molecule for their binding in the active site of adenylate cyclase are discussed.

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

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Lorenz Reinhard

2010-05-01

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.

Food restriction modulates β-adrenergic-sensitive adenylate cyclase in rat liver during aging

International Nuclear Information System (INIS)

Katz, M.S.

1988-01-01

Adenylate cyclase activities were studied in rat liver during postmaturational aging of male Fischer 344 rats fed ad libitum or restricted to 60% of the ad libitum intake. Catecholamine-stimulated adenylate cyclase activity increased by 200-300% between 6 and 24-27 mo of age in ad libitum-fed rats, whereas in food-restricted rats catecholamine response increased by only 58-84% between 6 and 30 mo. In ad libitum-fed rats, glucagon-stimulated enzyme activity also increased by 40% between 6 and 12 mo and in restricted rats a similar age-related increase was delayed until 18 mo. β-Adrenergic receptor density increased by 50% between 6 and 24 mo in livers from ad libitum-fed but not food-restricted rats and showed a highly significant correlation with maximal isoproterenol-stimulated adenylate cyclase activity over the postmaturational life span. Age-related increases in unstimulated (basal) adenylate cyclase activity and nonreceptor-mediated enzyme activation were retarded by food restriction. The results demonstrate that food restriction diminishes a marked age-related increase in β-adrenergic-sensitive adenylate cyclase activity of rat liver. Alterations of adrenergic-responsive adenylate cyclase with age and the modulatory effects of food restriction appear to be mediated by changes in both receptor and nonreceptor components of adenylate cyclase

Blocking S1P interaction with S1P1 receptor by a novel competitive S1P1-selective antagonist inhibits angiogenesis

International Nuclear Information System (INIS)

Fujii, Yasuyuki; Ueda, Yasuji; Ohtake, Hidenori; Ono, Naoya; Takayama, Tetsuo; Nakazawa, Kiyoshi; Igarashi, Yasuyuki; Goitsuka, Ryo

2012-01-01

Highlights: ► The effect of a newly developed S1P 1 -selective antagonist on angiogenic responses. ► S1P 1 is a critical component of VEGF-related angiogenic responses. ► S1P 1 -selective antagonist showed in vitro activity to inhibit angiogenesis. ► S1P 1 -selective antagonist showed in vivo activity to inhibit angiogenesis. ► The efficacy of S1P 1 -selective antagonist for anti-cancer therapies. -- Abstract: Sphingosine 1-phosphate receptor type 1 (S1P 1 ) was shown to be essential for vascular maturation during embryonic development and it has been demonstrated that substantial crosstalk exists between S1P 1 and other pro-angiogenic growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor. We developed a novel S1P 1 -selective antagonist, TASP0277308, which is structurally unrelated to S1P as well as previously described S1P 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 1 is a critical component of VEGF-related angiogenic responses and also provide evidence for the efficacy of TASP0277308 for anti-cancer therapies.

Recurrent adenylation domain replacement in the microcystin synthetase gene cluster

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Laakso Kati

2007-10-01

Full Text Available Abstract Background Microcystins are small cyclic heptapeptide toxins produced by a range of distantly related cyanobacteria. Microcystins are synthesized on large NRPS-PKS enzyme complexes. Many structural variants of microcystins are produced simulatenously. A recombination event between the first module of mcyB (mcyB1 and mcyC in the microcystin synthetase gene cluster is linked to the simultaneous production of microcystin variants in strains of the genus Microcystis. Results Here we undertook a phylogenetic study to investigate the order and timing of recombination between the mcyB1 and mcyC genes in a diverse selection of microcystin producing cyanobacteria. Our results provide support for complex evolutionary processes taking place at the mcyB1 and mcyC adenylation domains which recognize and activate the amino acids found at X and Z positions. We find evidence for recent recombination between mcyB1 and mcyC in strains of the genera Anabaena, Microcystis, and Hapalosiphon. We also find clear evidence for independent adenylation domain conversion of mcyB1 by unrelated peptide synthetase modules in strains of the genera Nostoc and Microcystis. The recombination events replace only the adenylation domain in each case and the condensation domains of mcyB1 and mcyC are not transferred together with the adenylation domain. Our findings demonstrate that the mcyB1 and mcyC adenylation domains are recombination hotspots in the microcystin synthetase gene cluster. Conclusion Recombination is thought to be one of the main mechanisms driving the diversification of NRPSs. However, there is very little information on how recombination takes place in nature. This study demonstrates that functional peptide synthetases are created in nature through transfer of adenylation domains without the concomitant transfer of condensation domains.

Thrombin-receptor antagonist vorapaxar in acute coronary syndromes

DEFF Research Database (Denmark)

Tricoci, Pierluigi; Huang, Zhen; Held, Claes

2012-01-01

Vorapaxar is a new oral protease-activated-receptor 1 (PAR-1) antagonist that inhibits thrombin-induced platelet activation.......Vorapaxar is a new oral protease-activated-receptor 1 (PAR-1) antagonist that inhibits thrombin-induced platelet activation....

Maintenance therapy with oxytocin antagonists for inhibiting preterm birth after threatened preterm labour.

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Papatsonis, Dimitri N M; Flenady, Vicki; Liley, Helen G

2013-10-13

In some women, an episode of preterm labour settles and does not result in immediate preterm birth. Subsequent treatment with tocolytic agents such as oxytocin receptor antagonists may then have the potential to prevent the recurrence of preterm labour, prolonging gestation, and preventing the adverse consequences of prematurity for the infant. To assess the effects of maintenance therapy with oxytocin antagonists administered by any route after an episode of preterm labour in order to delay or prevent preterm birth. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 July 2013), sought ongoing and unpublished trials by contacting experts in the field and searched the reference lists of relevant articles. Randomised controlled trials comparing oxytocin antagonists with any alternative tocolytic agent, placebo or no treatment, used for maintenance therapy after an episode of preterm labour. We used the standard methods of The Cochrane Collaboration and the Cochrane Pregnancy and Childbirth Group. Two review authors independently undertook evaluation of methodological quality and extracted trial data. This review includes one trial of 513 women. When compared with placebo, atosiban did not reduce preterm birth before 37 weeks (risk ratio (RR) 0.89; 95% confidence intervals (CI) 0.71 to 1.12), 32 weeks (RR 0.85; 95% CI 0.47 to 1.55), or 28 weeks (RR 0.75; 95% CI 0.28 to 2.01). No difference was shown in neonatal morbidity, or perinatal mortality. There is insufficient evidence to support the use of oxytocin receptor antagonists to inhibit preterm birth after a period of threatened or actual preterm labour. Any future trials using oxytocin antagonists or other drugs as maintenance therapy for preventing preterm birth should examine a variety of important infant outcome measures, including reduction of neonatal morbidity and mortality, and long-term infant follow-up. Future research should also focus on the pathophysiological pathways that

Effect of age and posture on human lymphocyte adenylate cyclase activity.

Science.gov (United States)

Mader, S L; Robbins, A S; Rubenstein, L Z; Tuck, M L; Scarpace, P J

1988-03-01

1. A number of age-related changes have been reported in the catecholamine-adrenoceptor-adenylate cyclase system. Most of the data available on these alterations come from resting subjects; the response to acute stress may provide additional insights into the age effect on these responses. 2. We measured supine and 10 min upright plasma noradrenaline and lymphocyte adenylate cyclase activity in ten healthy elderly subjects (age 66-80 years) and seven healthy young subjects (age 27-34 years). 3. Isoprenaline stimulation of lymphocyte adenylate cyclase activity was not significantly different between supine and upright positions or between elderly and young subjects. There was a marked increase in forskolin-stimulated adenylate cyclase activity in the upright posture in both elderly and young subjects. The increment over supine levels was 70% in the elderly (P less than 0.025) and 73% in the young (P less than 0.05). This enhanced forskolin activity was not seen in two young subjects who became syncopal. 4. These data suggest that enhanced forskolin-stimulated adenylate cyclase activity occurs after 10 min of upright posture in both elderly and young subjects, and may be relevant to immediate blood pressure regulation. We were unable to demonstrate any age-related differences in these acute adrenergic responses.

Mechanism of MenE inhibition by acyl-adenylate analogues and discovery of novel antibacterial agents.

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Matarlo, Joe S; Evans, Christopher E; Sharma, Indrajeet; Lavaud, Lubens J; Ngo, Stephen C; Shek, Roger; Rajashankar, Kanagalaghatta R; French, Jarrod B; Tan, Derek S; Tonge, Peter J

2015-10-27

MenE is an o-succinylbenzoyl-CoA (OSB-CoA) synthetase in the bacterial menaquinone biosynthesis pathway and is a promising target for the development of novel antibacterial agents. The enzyme catalyzes CoA ligation via an acyl-adenylate intermediate, and we have previously reported tight-binding inhibitors of MenE based on stable acyl-sulfonyladenosine analogues of this intermediate, including OSB-AMS (1), which has an IC50 value of ≤25 nM for Escherichia coli MenE. Herein, we show that OSB-AMS reduces menaquinone levels in Staphylococcus aureus, consistent with its proposed mechanism of action, despite the observation that the antibacterial activity of OSB-AMS is ∼1000-fold lower than the IC50 for enzyme inhibition. To inform the synthesis of MenE inhibitors with improved antibacterial activity, we have undertaken a structure-activity relationship (SAR) study stimulated by the knowledge that OSB-AMS can adopt two isomeric forms in which the OSB side chain exists either as an open-chain keto acid or a cyclic lactol. These studies revealed that negatively charged analogues of the keto acid form bind, while neutral analogues do not, consistent with the hypothesis that the negatively charged keto acid form of OSB-AMS is the active isomer. X-ray crystallography and site-directed mutagenesis confirm the importance of a conserved arginine for binding the OSB carboxylate. Although most lactol isomers tested were inactive, a novel difluoroindanediol inhibitor (11) with improved antibacterial activity was discovered, providing a pathway toward the development of optimized MenE inhibitors in the future.

Pharmacological characterization of the dopamine-sensitive adenylate cyclase in cockroach brain: evidence for a distinct dopamine receptor

International Nuclear Information System (INIS)

Orr, G.L.; Gole, J.W.D.; Notman, H.J.; Downer, R.G.H.

1987-01-01

Dopamine increases cyclic AMP production in crude membrane preparations of cockroach brain with plateaus in cyclic AMP production occurring between 1-10 μM and 10 mM. Maximal production of cyclic AMP is 2.25 fold greater than that of control values. Octopamine also increases cyclic AMP production with a Ka of 1.4 μM and maximal production 3.5 fold greater than that of control. 5-Hydroxytryptamine does not increase cyclic AMP production. The effects of octopamine and dopamine are fully additive. The vertebrate dopamine agonists ADTN and epinine stimulate the dopamine-sensitive adenylate cyclase (AC) with Ka values of 4.5 and 0.6 μM respectively and with maximal effectiveness 1.7 fold greater than that of control. The selective D 2 -dopamine agonist LY-171555 stimulates cyclic AMP production to a similar extent with a Ka of 50 μM. Other dopamine agonists have no stimulatory effects. With the exception of mianserin, 3 H-piflutixol is displaced from brain membranes by dopamine antagonists with an order of potency similar to that observed for the inhibition of dopamine-sensitive AC. The results indicate that the octopamine- and dopamine-sensitive AC in cockroach brain can be distinguished pharmacologically and the dopamine receptors coupled to AC have pharmacological characteristics distinct from vertebrate D 1 - and D 2 -dopamine receptors. 33 references, 3 figures, 2 tables

Characterization of beta-adrenergic receptors and adenylate cyclase activity in rat brown fat

International Nuclear Information System (INIS)

Baresi, L.A.; Morley, J.E.; Scarpace, P.J.

1986-01-01

Catecholamines stimulate thermogenesis in rat brown fat through a mechanism which involves binding to the beta-adrenergic receptor (BAR), stimulation of adenylate cyclase (AC) and culminating with uncoupling of mitochondrial respiration from ATP synthesis. The authors characterized BAR, AC and cytochrome (cyt) c oxidase in CDF (F-344) interscapular brown fat. Scatchard analysis of [ 125 ]Iodopindolol binding yields a straight line consistent with a single class of antagonist binding sites with 41.8 +/- 12.0 fmol BAR/mg protein and a K/sub d/ of 118 +/- 15 pM. Binding was both specific and stereospecific. Competition with 1-propranolol (K/sub d/ = 6.7 nM) was 15 times more potent than d-propranolol (K/sub d/ = 103 nM). Competition with isoproterenol (K/sub d/ = 79 nM) was 10 times more potent than epinephrine (K/sub d/ = 820 nM) which was 35 times more potent than norepinephrine (K/sub d/ = 2.9 x 10 -5 M) suggesting predominate beta 2 -type BAR. Cyt c oxidase activity was assessed in brown fat mitochrondrial preparations. The ratio of BAR to cyt c activity was 959 +/- 275 nmol BAR/mol cyc c/min. Isoproterenol (0.1 mM) stimulated AC activity was 24 times GTP (0.1 mM) stimulated AC (98.5 vs 40.7 pmol cAMP/min/mg). NaF-stimulated AC was nine times basal activity (90.5 vs 11.3 pmol cAMP/min/mg). These data demonstrate the presence of a beta- 2 -type BAR coupled to adenylate cyclase in rat brown fat

Optimization of ATP synthase function in mitochondria and chloroplasts via the adenylate kinase equilibrium

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Abir U Igamberdiev

2015-01-01

Full Text Available The bulk of ATP synthesis in plants is performed by ATP synthase, the main bioenergetics engine of cells, operating both in mitochondria and in chloroplasts. The reaction mechanism of ATP synthase has been studied in detail for over half a century; however, its optimal performance depends also on the steady delivery of ATP synthase substrates and the removal of its products. For mitochondrial ATP synthase, we analyze here the provision of stable conditions for (i the supply of ADP and Mg2+, supported by adenylate kinase (AK equilibrium in the intermembrane space, (ii the supply of phosphate via membrane transporter in symport with H+, and (iii the conditions of outflow of ATP by adenylate transporter carrying out the exchange of free adenylates. We also show that, in chloroplasts, AK equilibrates adenylates and governs Mg2+ contents in the stroma, optimizing ATP synthase and Calvin cycle operation, and affecting the import of inorganic phosphate in exchange with triose phosphates. It is argued that chemiosmosis is not the sole component of ATP synthase performance, which also depends on AK-mediated equilibrium of adenylates and Mg2+, adenylate transport and phosphate release and supply.

Benzodiazepine receptor antagonists for hepatic encephalopathy

DEFF Research Database (Denmark)

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

2004-01-01

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....

Natural separation of the acyl-CoA ligase reaction results in a non-adenylating enzyme.

Science.gov (United States)

Wang, Nan; Rudolf, Jeffrey D; Dong, Liao-Bin; Osipiuk, Jerzy; Hatzos-Skintges, Catherine; Endres, Michael; Chang, Chin-Yuan; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N; Shen, Ben

2018-06-04

Acyl-coenzyme A (CoA) ligases catalyze the activation of carboxylic acids via a two-step reaction of adenylation followed by thioesterification. Here, we report the discovery of a non-adenylating acyl-CoA ligase PtmA2 and the functional separation of an acyl-CoA ligase reaction. Both PtmA1 and PtmA2, two acyl-CoA ligases from the biosynthetic pathway of platensimycin and platencin, are necessary for the two steps of CoA activation. Gene inactivation of ptmA1 and ptmA2 resulted in the accumulation of free acid and adenylate intermediates, respectively. Enzymatic and structural characterization of PtmA2 confirmed its ability to only catalyze thioesterification. Structural characterization of PtmA2 revealed it binds both free acid and adenylate substrates and undergoes the established mechanism of domain alternation. Finally, site-directed mutagenesis restored both the adenylation and complete CoA activation reactions. This study challenges the currently accepted paradigm of adenylating enzymes and inspires future investigations on functionally separated acyl-CoA ligases and their ramifications in biology.

Direct demonstration of D1 dopamine receptors in the bovine parathyroid gland using the D1 selective antagonist [125I]-SCH 23982

International Nuclear Information System (INIS)

Monsma, F.J. Jr.; Sibley, D.R.

1989-01-01

The presence of D1 dopamine receptors in the parathyroid gland has been proposed based on the demonstration of dopaminergic regulation of adenylate cyclase activity and parathyroid hormone release in dispersed bovine parathyroid cells. Using a radioiodinated D1 selective antagonist [125I]-SCH 23982, we have now directly labeled and characterized the D1 dopamine receptors in bovine parathyroid gland membranes. [125I]-SCH 23982 binds in a saturable manner with high affinity and low nonspecific binding to membranes prepared from bovine parathyroid glands. D1 dopamine receptors are present in this preparation at a concentration of approximately 130 fMoles/mg protein and [125I]-SCH 23982 binding increases with increasing protein concentration in a linear fashion. Determination of the Kd using the association (k1) and dissociation (k-1) rate constants revealed good agreement with the Kd determined by saturation analysis (390 pM vs. 682 pM, respectively). Inhibition of 0.3 nM [125I]-SCH 23982 binding by a series of dopaminergic antagonists verified the D1 nature of this binding site, exhibiting appropriate affinities and rank order of potency. The competition curves of all antagonists exhibited Hill coefficients that were not significantly different from 1. Inhibition of [125I]-SCH 23982 binding by dopamine and other dopaminergic agonists revealed the presence of high and low affinity agonist binding sites. Addition of 200 microM GppNHp effected a complete conversion of high affinity dopamine binding sites to a homogeneous population of low affinity dopamine sites. The D1 receptors identified in the parathyroid gland with [125I]-SCH 23982 appear to be pharmacologically identical with those previously characterized in the central nervous system

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.

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: y.fujii@po.rd.taisho.co.jp [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)

2012-03-23

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.

Inhibition of the superantigenic activities of Staphylococcal enterotoxin A by an aptamer antagonist.

Science.gov (United States)

Wang, Kaiyu; Wu, Dong; Chen, Zhuang; Zhang, Xianhui; Yang, Xiangyue; Yang, Chaoyong James; Lan, Xiaopeng

2016-09-01

Staphylococcal enterotoxin A (SEA) is an important component of Staphylococcus aureus pathogenesis. SEA induces T lymphocytes activation and proliferation, resulting in the release of a large number of inflammatory cytokines. Blocking the toxic cascade triggered by SEA may be an effective strategy for the treatment of SEA-induced diseases. Through a systematic evolution of ligands by exponential enrichment process, we obtained an aptamer (S3) that could bind SEA with both high affinity and specificity, with a Kd value 36.93 ± 7.29 nM (n = 3). This aptamer antagonist effectively inhibited SEA-mediated human peripheral blood mononuclear cells proliferation and inflammatory cytokines (IFN-γ, TNF-α, IL-2 and IL-6) secretion. Moreover, PEGylated S3 significantly reduced mortality in murine lethal toxic shock models established by lipopolysaccharide-potentiated SEA. Therefore, this novel aptamer antagonist has the potential to become a new strategy for treating S. aureus infections and SEA-induced diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pituitary adenylate cyclase activating polypeptide induces vascular relaxation and inhibits non-vascular smooth muscle activity in the rabbit female genital tract

DEFF Research Database (Denmark)

Steenstrup, B R; Ottesen, B; Jørgensen, M

1994-01-01

In vitro effects of two bioactive forms of pituitary adenylate cyclase activating polypeptide (PACAP): PACAP-38 and PACAP-27 were studied on rabbit vascular and non-vascular smooth muscle. Segments of the ovarian artery and muscle strips from the fallopian tube were used. Two series of experiment...

Acute inhibition of selected membrane-proximal mouse T cell receptor signaling by mitochondrial antagonists.

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Kwangmi Kim

2009-11-01

Full Text Available T cells absorb nanometric membrane vesicles, prepared from plasma membrane of antigen presenting cells, via dual receptor/ligand interactions of T cell receptor (TCR with cognate peptide/major histocompatibility complex (MHC plus lymphocyte function-associated antigen 1 (LFA-1 with intercellular adhesion molecule 1. TCR-mediated signaling for LFA-1 activation is also required for the vesicle absorption. Exploiting those findings, we had established a high throughput screening (HTS platform and screened a library for isolation of small molecules inhibiting the vesicle absorption. Follow-up studies confirmed that treatments (1 hour with various mitochondrial antagonists, including a class of anti-diabetic drugs (i.e., Metformin and Phenformin, resulted in ubiquitous inhibition of the vesicle absorption without compromising viability of T cells. Further studies revealed that the mitochondrial drug treatments caused impairment of specific membrane-proximal TCR signaling event(s. Thus, activation of Akt and PLC-gamma1 and entry of extracellular Ca(2+ following TCR stimulation were attenuated while polymerization of monomeric actins upon TCR triggering progressed normally after the treatments. Dynamic F-actin rearrangement concurring with the vesicle absorption was also found to be impaired by the drug treatments, implying that the inhibition by the drug treatments of downstream signaling events (and the vesicle absorption could result from lack of directional relocation of signaling and cell surface molecules. We also assessed the potential application of mitochondrial antagonists as immune modulators by probing effects of the long-term drug treatments (24 hours on viability of resting primary T cells and cell cycle progression of antigen-stimulated T cells. This study unveils a novel regulatory mechanism for T cell immunity in response to environmental factors having effects on mitochondrial function.

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

2013-01-01

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 ac...

Characterization of muscarinic receptor subtypes in primary cultures of cerebellar granule cells using specific muscarinic receptor antagonists

International Nuclear Information System (INIS)

McLeskey, S.W.

1989-01-01

In cerebellar granule cell cultures, two muscarinic receptor mediated responses were observed: inhibition of adenylate cyclase (M-AC) and stimulation of phosphoinositide hydrolysis (M-PI). These responses were antagonized by three purported specific muscarinic antagonists: pirenzipine and (-)QNX (specific for M-PI) and methoctramine (specific for M-AC). However, the specificity for the three antagonists in blocking these responses is not comparable to the specificity observed in binding studies on these cells or to that quoted in the literature. Two peaks of molecular sizes were found in these cells corresponding to the two molecular sizes of muscarinic receptive proteins reported in the literature. Muscarinic receptive proteins were alkylated with 3 H-propylbenzilylcholine mustard followed by sodium dodecylsulfate polyacrylamide gel electrophoresis. Pirenzipine and (-)QNX were able to block alkylation of the high molecular size peak, which corresponds to the receptive protein m 3 reported in the literature. Methoctramine was able to block alkylation of a portion of the lower molecular size peak, possibly corresponding to the m 2 and/or m 4 receptive proteins reported in the literature. Studies attempting to show the presence of receptor reserve for either of the two biochemical responses present in these cells by alkylation of the receptive protein with nonradiolabeled propylbenzilylcholine mustard (PBCM) were confounded by specificity of this agent for the lower molecular weight peak of muscarinic receptive protein. Thus the muscarinic receptive proteins coupled to M-AC were alkylated preferentially over the ones coupled to M-PI

Pituitary adenylate cyclase activating peptide (PACAP participates in adipogenesis by activating ERK signaling pathway.

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Tatjana Arsenijevic

Full Text Available Pituitary adenylate cyclase activating peptide (PACAP belongs to the secretin/glucagon/vasoactive intestinal peptide (VIP family. Its action can be mediated by three different receptor subtypes: PAC1, which has exclusive affinity for PACAP, and VPAC1 and VPAC2 which have equal affinity for PACAP and VIP. We showed that all three receptors are expressed in 3T3-L1 cells throughout their differentiation into adipocytes. We established the activity of these receptors by cAMP accumulation upon induction by PACAP. Together with insulin and dexamethasone, PACAP induced adipogenesis in 3T3-L1 cell line. PACAP increased cAMP production within 15 min upon stimulation and targeted the expression and phosphorylation of MAPK (ERK1/2, strengthened by the ERK1/2 phosphorylation being partially or completely abolished by different combinations of PACAP receptors antagonists. We therefore speculate that ERK1/2 activation is crucial for the activation of CCAAT/enhancer- binding protein β (C/EBPβ.

Pituitary adenylate cyclase activating polypeptide and migraine

DEFF Research Database (Denmark)

Zagami, Alessandro S; Edvinsson, Lars; Goadsby, Peter J

2014-01-01

Pituitary adenylate cyclase activating peptide (PACAP) is found in human trigeminocervical complex and can trigger migraine. PACAP levels were measured using a sensitive radioimmunoassay. Stimulation of the superior sagittal sinus (SSS) in cat elevated PACAP levels in cranial blood. Patients...

Mutating the Conserved Q-loop Glutamine 1291 Selectively Disrupts Adenylate Kinase-dependent Channel Gating of the ATP-binding Cassette (ABC) Adenylate Kinase Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and Reduces Channel Function in Primary Human Airway Epithelia.

Science.gov (United States)

Dong, Qian; Ernst, Sarah E; Ostedgaard, Lynda S; Shah, Viral S; Ver Heul, Amanda R; Welsh, Michael J; Randak, Christoph O

2015-05-29

The ATP-binding cassette (ABC) transporter cystic fibrosis transmembrane conductance regulator (CFTR) and two other non-membrane-bound ABC proteins, Rad50 and a structural maintenance of chromosome (SMC) protein, exhibit adenylate kinase activity in the presence of physiologic concentrations of ATP and AMP or ADP (ATP + AMP ⇆ 2 ADP). The crystal structure of the nucleotide-binding domain of an SMC protein in complex with the adenylate kinase bisubstrate inhibitor P(1),P(5)-di(adenosine-5') pentaphosphate (Ap5A) suggests that AMP binds to the conserved Q-loop glutamine during the adenylate kinase reaction. Therefore, we hypothesized that mutating the corresponding residue in CFTR, Gln-1291, selectively disrupts adenylate kinase-dependent channel gating at physiologic nucleotide concentrations. We found that substituting Gln-1291 with bulky side-chain amino acids abolished the effects of Ap5A, AMP, and adenosine 5'-monophosphoramidate on CFTR channel function. 8-Azidoadenosine 5'-monophosphate photolabeling of the AMP-binding site and adenylate kinase activity were disrupted in Q1291F CFTR. The Gln-1291 mutations did not alter the potency of ATP at stimulating current or ATP-dependent gating when ATP was the only nucleotide present. However, when physiologic concentrations of ADP and AMP were added, adenylate kinase-deficient Q1291F channels opened significantly less than wild type. Consistent with this result, we found that Q1291F CFTR displayed significantly reduced Cl(-) channel function in well differentiated primary human airway epithelia. These results indicate that a highly conserved residue of an ABC transporter plays an important role in adenylate kinase-dependent CFTR gating. Furthermore, the results suggest that adenylate kinase activity is important for normal CFTR channel function in airway epithelia. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Comparison between dopamine-stimulated adenylate cyclase and 3H-SCH 23390 binding in rat striatum

International Nuclear Information System (INIS)

Andersen, P.H.; Groenvald, F.C.; Jansen, J.A.

1985-01-01

Methods for measuring 3 H-SCH 23990 binding and dopamine (DA) stimulated adenylate cyclase (AC) were established in identical tissue preparations and under similar experimental conditions. Pharmacological characterization revealed that both assays involved interaction with the D1 receptor or closely associated sites. In order to investigate whether the binding sites for 3 H-SCH 23390 and DA in fact are identical, the antagonistic effects of a variety of pharmacologically active compounds were examined. Surprisingly, the K/sub i/-values obtained from Schild-plot analysis of the antagonism of DA-stimulated AC, were 80-240 times higher than the K/sub i/-values obtained from competition curves of 3 H-SCH 23390 binding. Since both assays were performed under identical conditions, the differences in K/sub i/-values indicate the possibility of different binding sites for DA and 3 H-SCH 23390 or, that DA and 3 -SCH 23390 label different states of the same receptor. 19 references, 7 figures, 2 tables

Inhibition of luminescence and virulence in the black tiger prawn (Penaeus monodon) pathogen Vibrio harveyi by intercellular signal antagonists.

Science.gov (United States)

Manefield, M; Harris, L; Rice, S A; de Nys, R; Kjelleberg, S

2000-05-01

Expression of luminescence in the Penaeus monodon pathogen Vibrio harveyi is regulated by an intercellular quorum sensing mechanism involving the synthesis and detection of two signaling molecules, one of which is N-hydroxy butanoyl-L-homoserine lactone and the other of which is uncharacterized. Indirect evidence has suggested that virulence, associated with a toxic extracellular protein, and luminescence in V. harveyi are coregulated. In this study the effects of an acylated homoserine lactone antagonist produced by the marine alga Delisea pulchra on luminescence and toxin production in a virulent strain of V. harveyi were analyzed. Luminescence and toxin production were both inhibited by the signal antagonist at concentrations that had no impact on growth. Toxin production was found to be prematurely induced in V. harveyi cultures incubated in a 10% conditioned medium. Additionally, a significant reduction in the toxicity of concentrated supernatant extracts from V. harveyi cultures incubated in the presence of the signal antagonist, as measured by in vivo toxicity assays in mice and prawns, was observed. These results suggest that intercellular signaling antagonists have potential utility in the control of V. harveyi prawn infections.

Inhibition of Luminescence and Virulence in the Black Tiger Prawn (Penaeus monodon) Pathogen Vibrio harveyi by Intercellular Signal Antagonists

Science.gov (United States)

Manefield, Michael; Harris, Lachlan; Rice, Scott A.; de Nys, Rocky; Kjelleberg, Staffan

2000-01-01

Expression of luminescence in the Penaeus monodon pathogen Vibrio harveyi is regulated by an intercellular quorum sensing mechanism involving the synthesis and detection of two signaling molecules, one of which is N-hydroxy butanoyl-l-homoserine lactone and the other of which is uncharacterized. Indirect evidence has suggested that virulence, associated with a toxic extracellular protein, and luminescence in V. harveyi are coregulated. In this study the effects of an acylated homoserine lactone antagonist produced by the marine alga Delisea pulchra on luminescence and toxin production in a virulent strain of V. harveyi were analyzed. Luminescence and toxin production were both inhibited by the signal antagonist at concentrations that had no impact on growth. Toxin production was found to be prematurely induced in V. harveyi cultures incubated in a 10% conditioned medium. Additionally, a significant reduction in the toxicity of concentrated supernatant extracts from V. harveyi cultures incubated in the presence of the signal antagonist, as measured by in vivo toxicity assays in mice and prawns, was observed. These results suggest that intercellular signaling antagonists have potential utility in the control of V. harveyi prawn infections. PMID:10788385

Adenylate Kinase and AMP Signaling Networks: Metabolic Monitoring, Signal Communication and Body Energy Sensing

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Andre Terzic

2009-04-01

Full Text Available Adenylate kinase and downstream AMP signaling is an integrated metabolic monitoring system which reads the cellular energy state in order to tune and report signals to metabolic sensors. A network of adenylate kinase isoforms (AK1-AK7 are distributed throughout intracellular compartments, interstitial space and body fluids to regulate energetic and metabolic signaling circuits, securing efficient cell energy economy, signal communication and stress response. The dynamics of adenylate kinase-catalyzed phosphotransfer regulates multiple intracellular and extracellular energy-dependent and nucleotide signaling processes, including excitation-contraction coupling, hormone secretion, cell and ciliary motility, nuclear transport, energetics of cell cycle, DNA synthesis and repair, and developmental programming. Metabolomic analyses indicate that cellular, interstitial and blood AMP levels are potential metabolic signals associated with vital functions including body energy sensing, sleep, hibernation and food intake. Either low or excess AMP signaling has been linked to human disease such as diabetes, obesity and hypertrophic cardiomyopathy. Recent studies indicate that derangements in adenylate kinase-mediated energetic signaling due to mutations in AK1, AK2 or AK7 isoforms are associated with hemolytic anemia, reticular dysgenesis and ciliary dyskinesia. Moreover, hormonal, food and antidiabetic drug actions are frequently coupled to alterations of cellular AMP levels and associated signaling. Thus, by monitoring energy state and generating and distributing AMP metabolic signals adenylate kinase represents a unique hub within the cellular homeostatic network.

Characterization of cutaneous vascular permeability induced by platelet-activating factor in guinea pigs and rats and its inhibition by a platelet-activating factor receptor antagonist

International Nuclear Information System (INIS)

Hwang, S.B.; Li, C.L.; Lam, M.H.; Shen, T.Y.

1985-01-01

Mechanisms of platelet-activating factor (PAF)-induced increases of cutaneous vascular permeability in guinea pigs and in rats were further explored. PAF so far is the most potent vasoactive mediator, being more than 1000-fold more potent than histamine and bradykinin in both species. In guinea pigs, there is a time delay of 5 to 10 minutes before PAF action, whereas, in the rat, the increased vasopermeability occurs immediately following the intradermal PAF injection. Relative vasoactive potencies of PAF and several structure-related analogues in both species correlate very well with their relative inhibition of the binding of 3 H-PAF to specific receptor sites on isolated rabbit platelet plasma membranes and their aggregatory abilities of rabbit platelets. Furthermore, the PAF-induced cutaneous vascular permeability is inhibitable by a competitive specific PAF receptor antagonist, kadsurenone, suggesting that binding of PAF to its specific receptor site is the first step to initiate its action of increased cutaneous vascular permeability. Several pure cyclooxygenase inhibitors, including indomethacin, diflunisal, and flurbiprofen, and the dual cyclooxygenase/lipoxygenase inhibitor, BW755C, but not the histamine antagonists, inhibit the PAF-induced vasopermeability in guinea pigs. The inhibition by indomethacin or BW755C can be fully reversed by coinjection intradermally with PAF and prostaglandin E1 but not leukotriene B4. Also, prostaglandin E1 but not leukotriene B4 enhances the guinea pig in vivo response to PAF in this model. However, in rats, none of the cyclooxygenase inhibitors, histamine antagonists, or BW755C inhibit the PAF effect of cutaneous phenomena

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.

The pimeloyl-CoA synthetase BioW defines a new fold for adenylate-forming enzymes

Energy Technology Data Exchange (ETDEWEB)

Estrada, Paola; Manandhar, Miglena; Dong, Shi-Hui; Deveryshetty, Jaigeeth; Agarwal, Vinayak; Cronan, John E.; Nair, Satish K.

2017-04-17

Reactions that activate carboxylates through acyl-adenylate intermediates are found throughout biology and include acyl- and aryl-CoA synthetases and tRNA synthetases. Here we describe the characterization of Aquifex aeolicus BioW, which represents a new protein fold within the superfamily of adenylating enzymes. Substrate-bound structures identified the enzyme active site and elucidated the mechanistic strategy for conjugating CoA to the seven-carbon α,ω-dicarboxylate pimelate, a biotin precursor. Proper position of reactive groups for the two half-reactions is achieved solely through movements of active site residues, as confirmed by site-directed mutational analysis. The ability of BioW to hydrolyze adenylates of noncognate substrates is reminiscent of pre-transfer proofreading observed in some tRNA synthetases, and we show that this activity can be abolished by mutation of a single residue. These studies illustrate how BioW can carry out three different biologically prevalent chemical reactions (adenylation, thioesterification, and proofreading) in the context of a new protein fold.

MDM2 Antagonists Counteract Drug-Induced DNA Damage

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Anna E. Vilgelm

2017-10-01

Full Text Available Antagonists of MDM2-p53 interaction are emerging anti-cancer drugs utilized in clinical trials for malignancies that rarely mutate p53, including melanoma. We discovered that MDM2-p53 antagonists protect DNA from drug-induced damage in melanoma cells and patient-derived xenografts. Among the tested DNA damaging drugs were various inhibitors of Aurora and Polo-like mitotic kinases, as well as traditional chemotherapy. Mitotic kinase inhibition causes mitotic slippage, DNA re-replication, and polyploidy. Here we show that re-replication of the polyploid genome generates replicative stress which leads to DNA damage. MDM2-p53 antagonists relieve replicative stress via the p53-dependent activation of p21 which inhibits DNA replication. Loss of p21 promoted drug-induced DNA damage in melanoma cells and enhanced anti-tumor activity of therapy combining MDM2 antagonist with mitotic kinase inhibitor in mice. In summary, MDM2 antagonists may reduce DNA damaging effects of anti-cancer drugs if they are administered together, while targeting p21 can improve the efficacy of such combinations.

Fasitibant chloride, a kinin B2 receptor antagonist, and dexamethasone interact to inhibit carrageenan-induced inflammatory arthritis in rats

Science.gov (United States)

Valenti, Claudio; Giuliani, Sandro; Cialdai, Cecilia; Tramontana, Manuela; Maggi, Carlo Alberto

2012-01-01

BACKGROUND AND PURPOSE Bradykinin, through the kinin B2 receptor, is involved in inflammatory processes related to arthropathies. B2 receptor antagonists inhibited carrageenan-induced arthritis in rats in synergy with anti-inflammatory steroids. The mechanism(s) underlying this drug interaction was investigated. EXPERIMENTAL APPROACH Drugs inhibiting inflammatory mediators released by carrageenan were injected, alone or in combination, into the knee joint of pentobarbital anaesthetized rats 30 min before intra-articular administration of carrageenan. Their effects on the carrageenan-induced inflammatory responses (joint pain, oedema and neutrophil recruitment) and release of inflammatory mediators (prostaglandins, IL-1β, IL-6 and the chemokine GRO/CINC-1), were assessed after 6 h. KEY RESULTS The combination of fasitibant chloride (MEN16132) and dexamethasone was more effective than each drug administered alone in inhibiting knee joint inflammation and release of inflammatory mediators. Fasitibant chloride, MK571, atenolol, des-Arg9-[Leu8]-bradykinin (B2 receptor, leukotriene, catecholamine and B1 receptor antagonists, respectively) and dexketoprofen (COX inhibitor), reduced joint pain and, except for the latter, also diminished joint oedema. A combination of drugs inhibiting joint pain (fasitibant chloride, des-Arg9-[Leu8]-bradykinin, dexketoprofen, MK571 and atenolol) and oedema (fasitibant chloride, des-Arg9-[Leu8]-bradykinin, MK571 and atenolol) abolished the respective inflammatory response, producing inhibition comparable with that achieved with the combination of fasitibant chloride and dexamethasone. MK571 alone was able to block neutrophil recruitment. CONCLUSIONS AND IMPLICATIONS Bradykinin-mediated inflammatory responses to intra-articular carrageenan were not controlled by steroids, which were not capable of preventing bradykinin effects either by direct activation of the B2 receptor, or through the indirect effects mediated by release of eicosanoids

Chronic changes in pituitary adenylate cyclase-activating polypeptide and related receptors in response to repeated chemical dural stimulation in rats.

Science.gov (United States)

Han, Xun; Ran, Ye; Su, Min; Liu, Yinglu; Tang, Wenjing; Dong, Zhao; Yu, Shengyuan

2017-01-01

Background Preclinical experimental studies revealed an acute alteration of pituitary adenylate cyclase-activating polypeptide in response to a single activation of the trigeminovascular system, which suggests a potential role of pituitary adenylate cyclase-activating polypeptide in the pathogenesis of migraine. However, changes in pituitary adenylate cyclase-activating polypeptide after repeated migraine-like attacks in chronic migraine are not clear. Therefore, the present study investigated chronic changes in pituitary adenylate cyclase-activating polypeptide and related receptors in response to repeated chemical dural stimulations in the rat. Methods A rat model of chronic migraine was established by repeated chemical dural stimulations using an inflammatory soup for a different numbers of days. The pituitary adenylate cyclase-activating polypeptide levels were quantified in plasma, the trigeminal ganglia, and the trigeminal nucleus caudalis using radioimmunoassay and Western blotting in trigeminal ganglia and trigeminal nucleus caudalis tissues. Western blot analysis and real-time polymerase chain reaction were used to measure the protein and mRNA expression of pituitary adenylate cyclase-activating polypeptide-related receptors (PAC1, VPAC1, and VPAC2) in the trigeminal ganglia and trigeminal nucleus caudalis to identify changes associated with repetitive applications of chemical dural stimulations. Results All rats exhibited significantly decreased periorbital nociceptive thresholds to repeated inflammatory soup stimulations. Radioimmunoassay and Western blot analysis demonstrated significantly decreased pituitary adenylate cyclase-activating polypeptide levels in plasma and trigeminal ganglia after repetitive chronic inflammatory soup stimulation. Protein and mRNA analyses of pituitary adenylate cyclase-activating polypeptide-related receptors demonstrated significantly increased PAC1 receptor protein and mRNA expression in the trigeminal ganglia, but not

Role of MbtH-like Proteins in the Adenylation of Tyrosine during Aminocoumarin and Vancomycin Biosynthesis*

Science.gov (United States)

Boll, Björn; Taubitz, Tatjana; Heide, Lutz

2011-01-01

MbtH-like proteins consist of ∼70 amino acids and are encoded in the biosynthetic gene clusters of non-ribosomally formed peptides and other secondary metabolites derived from amino acids. Recently, several MbtH-like proteins have been shown to be required for the adenylation of amino acid in non-ribosomal peptide synthesis. We now investigated the role of MbtH-like proteins in the biosynthesis of the aminocoumarin antibiotics novobiocin, clorobiocin, and simocyclinone D8 and of the glycopeptide antibiotic vancomycin. The tyrosine-adenylating enzymes CloH, SimH, and Pcza361.18, involved in the biosynthesis of clorobiocin, simocyclinone D8, and vancomycin, respectively, required the presence of MbtH-like proteins in a 1:1 molar ratio, forming heterotetrameric complexes. In contrast, NovH, involved in novobiocin biosynthesis, showed activity in the absence of MbtH-like proteins. Comparison of the active centers of CloH and NovH showed only one amino acid to be different, i.e. Leu-383 versus Met-383. Mutation of this amino acid in CloH (L383M) indeed led to MbtH-independent adenylating activity. All investigated tyrosine-adenylating enzymes exhibited remarkable promiscuity for MbtH-like proteins from different pathways and organisms. YbdZ, the MbtH-like protein from the expression host Escherichia coli, was found to bind to adenylating enzymes during expression and to influence their biochemical properties markedly. Therefore, the use of ybdZ-deficient expression hosts is important in biochemical studies of adenylating enzymes. PMID:21890635

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

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Nayyar Ahmed

2015-05-01

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.

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

2008-01-01

At the onset of dorsiflexion disynaptic reciprocal inhibition (DRI) of soleus motoneurons is increased to prevent activation of the antagonistic plantar flexors. This is caused by descending facilitation of transmission in the DRI pathway. Because the risk of eliciting stretch reflexes in the ankle...... of the ankle dorsiflexor muscles 3 times a week for 4 wk. Test sessions were conducted before, shortly after, and 2 wk after the training period. The rate of torque development measured at 30, 50, 100, and 200 ms after onset of voluntary explosive isometric dorsiflexion increased by 24-33% (P

A cost-effective method for Illumina small RNA-Seq library preparation using T4 RNA ligase 1 adenylated adapters

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Chen Yun-Ru

2012-09-01

Full Text Available Abstract Background Deep sequencing is a powerful tool for novel small RNA discovery. Illumina small RNA sequencing library preparation requires a pre-adenylated 3’ end adapter containing a 5’,5’-adenyl pyrophosphoryl moiety. In the absence of ATP, this adapter can be ligated to the 3’ hydroxyl group of small RNA, while RNA self-ligation and concatenation are repressed. Pre-adenylated adapters are one of the most essential and costly components required for library preparation, and few are commercially available. Results We demonstrate that DNA oligo with 5’ phosphate and 3’ amine groups can be enzymatically adenylated by T4 RNA ligase 1 to generate customized pre-adenylated adapters. We have constructed and sequenced a small RNA library for tomato (Solanum lycopersicum using the T4 RNA ligase 1 adenylated adapter. Conclusion We provide an efficient and low-cost method for small RNA sequencing library preparation, which takes two days to complete and costs around $20 per library. This protocol has been tested in several plant species for small RNA sequencing including sweet potato, pepper, watermelon, and cowpea, and could be readily applied to any RNA samples.

Bordetella adenylate cyclase toxin: a unique combination of a pore-forming moiety with a cell-invading adenylate cyclase enzyme

Czech Academy of Sciences Publication Activity Database

Mašín, Jiří; Osička, Radim; Bumba, Ladislav; Šebo, Peter

2015-01-01

Roč. 73, č. 8 (2015) ISSN 2049-632X R&D Projects: GA ČR GAP302/12/0460; GA ČR GA15-09157S; GA ČR(CZ) GA15-11851S Institutional support: RVO:61388971 Keywords : adenylate cyclase toxin * membrane penetration * pore-formation Subject RIV: EE - Microbiology, Virology Impact factor: 2.483, year: 2015

Evaluation of antagonistic fungi against charcoal rot of sunflower ...

African Journals Online (AJOL)

In vitro, sensitivity of Macrophomina phaseolina (Tassi) Goid determined through inhibition zone technique to various antagonistic fungi viz., Aspergillus niger, Aspergillus flavus, Trichoderma viride, Trichoderma harzianum and Penicillium capsulatum amended into PDA medium. All the antagonists reduced the colony ...

Synthesis and preliminary evaluation of [3H]PSB-0413, a selective antagonist radioligand for platelet P2Y12 receptors.

Science.gov (United States)

El-Tayeb, Ali; Griessmeier, Kerstin J; Müller, Christa E

2005-12-15

The selective antagonist radioligand [(3)H]2-propylthioadenosine-5'-adenylic acid (1,1-dichloro-1-phosphonomethyl-1-phosphonyl) anhydride ([(3)H]PSB-0413) was prepared by catalytic hydrogenation of its propargyl precursor with a high specific radioactivity of 74Ci/mmol. In preliminary saturation binding studies, [(3)H]PSB-0413 showed high affinity for platelet P2Y(12) receptors with a K(D) value of 4.57nM. Human platelets had a high density of P2Y(12) receptors exhibiting a B(max) value of 7.66pmol/mg of protein.

Structural and Functional Studies of Fatty Acyl Adenylate Ligases from E. coli and L. pneumophila

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z.; Swaminathan, S.; Zhou, R.; Sauder, J. M.; Tonge, P. J.; Burley, S. K.

2011-02-18

Fatty acyl-AMP ligase (FAAL) is a new member of a family of adenylate-forming enzymes that were recently discovered in Mycobacterium tuberculosis. They are similar in sequence to fatty acyl-coenzyme A (CoA) ligases (FACLs). However, while FACLs perform a two-step catalytic reaction, AMP ligation followed by CoA ligation using ATP and CoA as cofactors, FAALs produce only the acyl adenylate and are unable to perform the second step. We report X-ray crystal structures of full-length FAAL from Escherichia coli (EcFAAL) and FAAL from Legionella pneumophila (LpFAAL) bound to acyl adenylate, determined at resolution limits of 3.0 and 1.85 {angstrom}, respectively. The structures share a larger N-terminal domain and a smaller C-terminal domain, which together resemble the previously determined structures of FAAL and FACL proteins. Our two structures occur in quite different conformations. EcFAAL adopts the adenylate-forming conformation typical of FACLs, whereas LpFAAL exhibits a unique intermediate conformation. Both EcFAAL and LpFAAL have insertion motifs that distinguish them from the FACLs. Structures of EcFAAL and LpFAAL reveal detailed interactions between this insertion motif and the interdomain hinge region and with the C-terminal domain. We suggest that the insertion motifs support sufficient interdomain motions to allow substrate binding and product release during acyl adenylate formation, but they preclude CoA binding, thereby preventing CoA ligation.

Human fat cell alpha-2 adrenoceptors. I. Functional exploration and pharmacological definition with selected alpha-2 agonists and antagonists

International Nuclear Information System (INIS)

Galitzky, J.; Mauriege, P.; Berlan, M.; Lafontan, M.

1989-01-01

This study was undertaken to investigate more fully the pharmacological characteristics of the human fat cell alpha-2 adrenoceptor. Biological assays were performed on intact isolated fat cells while radioligand binding studies were carried out with [ 3 H]yohimbine in membranes. These pharmacological studies brought: (1) a critical definition of the limits of the experimental conditions required for the exploration of alpha-2 adrenergic responsiveness on human fat cells and membranes; (2) an improvement in the pharmacological definition of the human fat cell postsynaptic alpha-2 adrenoceptor. Among alpha-2 agonists, UK-14,304 was the most potent and the relative order of potency was: UK-14,304 greater than p-aminoclonidine greater than clonidine = B-HT 920 greater than rilmenidine. For alpha-2 antagonists, the potency order was: yohimbine greater than idazoxan greater than SK ampersand F-86,466 much greater than benextramine; (3) a description of the impact of benextramine (irreversible alpha-1/alpha-2 antagonist) on human fat cell alpha-2 adrenergic receptors and on human fat cell function; the drug inactivates the alpha-2 adrenergic receptors with a minor impact on beta adrenergic receptors and without noticeable alterations of fat cell function as assessed by preservation of beta adrenergic and Al-adenosine receptor-mediated lipolytic responses; and (4) a definition of the relationship existing between alpha-2 adrenergic receptor occupancy, inhibition of adenylate cyclase activity and antilipolysis with full and partial agonists. The existence of a receptor reserve must be taken into account when evaluating alpha-2 adrenergic receptor distribution and regulation of human fat cells

The Antidepressant 5-HT2A Receptor Antagonists Pizotifen and Cyproheptadine Inhibit Serotonin-Enhanced Platelet Function

Science.gov (United States)

Lin, Olivia A.; Karim, Zubair A.; Vemana, Hari Priya; Espinosa, Enma V. P.; Khasawneh, Fadi T.

2014-01-01

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 EMD 281014, their

Thyroid-stimulating immunoglobulins in Hashimoto's thyroiditis measured by radioreceptor assay and adenylate cyclase stimulation and their relationship to HLA-D alleles

International Nuclear Information System (INIS)

Bliddal, H.; Bech, K.; Feldt-Rasmussen, U.; Thomsen, M.; Ryder, L.P.; Hansen, J.M.; Siersbaek-Nielsen, K.; Friis, T.

1982-01-01

The relationship between thyroid-stimulating immunoglobulins, measured by both radioreceptor assay and adenylate cyclase stimulation, and the HLA alleles was studied in 41 patients with Hashimoto's thyroiditis. TSH binding-inhibiting immunoglobulins (TBII) were detected in 9 (22%) patients, and human thyroid adenylate cyclase-stimulating immunoglobulins (HTACS) were found in 21 (51%) patients. Only 2 patients were positive in both assays, and an inverse relationship was observed between TBII and HTACS. In the 21 HTACS-positive patients, HLA-Dw5 was found in 1 subject, compared to 8 of the 20 HTACS-negative patients (P < 0.01), while 4 of the 9 TBII-positive patients had HLA-Dw5 compared to 5 of the 32 TBII-negative subjects (P = 0.09).No significant relations were observed between the presence of HTACS or TBII and HLA-Dw3 or HLA-B8. It is concluded that TBII and HTACS are produced independently in Hashimoto's thyroiditis, and that the production of these autoantibodies seems to be related to the HLA-D region in this disease

Mechanistic Insights from the Crystal Structure of Bacillus subtilis o-Succinylbenzoyl-CoA Synthetase Complexed with the Adenylate Intermediate.

Science.gov (United States)

Chen, Yaozong; Jiang, Yiping; Guo, Zhihong

2016-12-06

o-Succinylbenzoyl-CoA (OSB-CoA) synthetase, or MenE, catalyzes an essential step in vitamin K biosynthesis and is a valuable drug target. Like many other adenylating enzymes, it changes its structure to accommodate substrate binding, catalysis, and product release along the path of a domain alternation catalytic mechanism. We have determined the crystal structure of its complex with the adenylation product, o-succinylbenzoyl-adenosine monophosphate (OSB-AMP), and captured a new postadenylation state. This structure presents unique features such as a strained conformation for the bound adenylate intermediate to indicate that it represents the enzyme state after completion of the adenylation reaction but before release of the C domain in its transition to the thioesterification conformation. By comparison to the ATP-bound preadenylation conformation, structural changes are identified in both the reactants and the active site to allow inference about how these changes accommodate and facilitate the adenylation reaction and to directly support an in-line backside attack nucleophilic substitution mechanism for the first half-reaction. Mutational analysis suggests that the conserved His196 plays an important role in desolvation of the active site rather than stabilizing the transition state of the adenylation reaction. In addition, comparison of the new structure with a previously determined OSB-AMP-bound structure of the same enzyme allows us to propose a release mechanism of the C domain in its alteration to form the thioesterification conformation. These findings allow us to better understand the domain alternation catalytic mechanism of MenE as well as many other adenylating enzymes.

Structural basis of the interaction of MbtH-like proteins, putative regulators of nonribosomal peptide biosynthesis, with adenylating enzymes.

Science.gov (United States)

Herbst, Dominik A; Boll, Björn; Zocher, Georg; Stehle, Thilo; Heide, Lutz

2013-01-18

The biosynthesis of nonribosomally formed peptides (NRPs), which include important antibiotics such as vancomycin, requires the activation of amino acids through adenylate formation. The biosynthetic gene clusters of NRPs frequently contain genes for small, so-called MbtH-like proteins. Recently, it was discovered that these MbtH-like proteins are required for some of the adenylation reactions in NRP biosynthesis, but the mechanism of their interaction with the adenylating enzymes has remained unknown. In this study, we determined the structure of SlgN1, a 3-methylaspartate-adenylating enzyme involved in the biosynthesis of the hybrid polyketide/NRP antibiotic streptolydigin. SlgN1 contains an MbtH-like domain at its N terminus, and our analysis defines the parameters required for an interaction between MbtH-like domains and an adenylating enzyme. Highly conserved tryptophan residues of the MbtH-like domain critically contribute to this interaction. Trp-25 and Trp-35 form a cleft on the surface of the MbtH-like domain, which accommodates the alanine side chain of Ala-433 of the adenylating domain. Mutation of Ala-433 to glutamate abolished the activity of SlgN1. Mutation of Ser-23 of the MbtH-like domain to tyrosine resulted in strongly reduced activity. However, the activity of this S23Y mutant could be completely restored by addition of the intact MbtH-like protein CloY from another organism. This suggests that the interface found in the structure of SlgN1 is the genuine interface between MbtH-like proteins and adenylating enzymes.

Adenylate Nucleotides and 2,3-Biphosphoglycerate Concentration in Erythrocytes of Growing Wielkopolska Stallions

OpenAIRE

M. Suska; E. Skotnicka; W. Dudzińska; W. Orowicz; M. Brzezinska

2006-01-01

The aim of this study was to examine the relationships between the concentrations of adenylate nucleotides (ATP, ADP, AMP), total nucleotide pool (TAN), adenylate energy charge (AEC) and 2,3-biphosphoglycerate (2,3-BPG) in the erythrocytes of young horses in the period of their rapid growth and development. The studies were conducted on 10 young Wielkopolska breed stallions for two years; Group A: 1-month-old, Group B: 3-month-old, Group C: 6-month-old, Group D: 1-year-old, and Group E: 2-yea...

FGFR antagonist induces protective autophagy in FGFR1-amplified breast cancer cell

International Nuclear Information System (INIS)

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

2016-01-01

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. -- Highlights: •FGFR1 antagonist inhibits cell viability in FGFR1-amplified breast cancer cells. •FGFR1 antagonist induces autophagy in FGFR1-amplified breast cancer cells. •FGFR1 antagonist-induced autophagy is protective. •FGFR1 antagonist induces autophagy by inhibiting Akt/mTOR pathway.

FGFR antagonist induces protective autophagy in FGFR1-amplified breast cancer cell

Energy Technology Data Exchange (ETDEWEB)

Chen, Yi [The School of Biomedical Sciences, Chengdu Medical College, Chengdu 610083 (China); Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Chengdu (China); Xie, Xiaoyan; Li, Xinyi; Wang, Peiqi [State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University (China); Jing, Qian; Yue, Jiaqi; Liu, Yang [The School of Biomedical Sciences, Chengdu Medical College, Chengdu 610083 (China); Cheng, Zhong [Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Chengdu (China); Li, Jingyi, E-mail: li--jingyi@hotmail.com [The School of Biomedical Sciences, Chengdu Medical College, Chengdu 610083 (China); Song, Haixing [The School of Biomedical Sciences, Chengdu Medical College, Chengdu 610083 (China); Li, Guoyu, E-mail: liguoyulisa@163.com [School of Pharmacy, Shihezi University, Shihezi 832003 (China); Liu, Rui, E-mail: liurui_scu@hotmail.com [State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University (China); Wang, Jinhui [School of Pharmacy, Shihezi University, Shihezi 832003 (China)

2016-05-20

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. -- Highlights: •FGFR1 antagonist inhibits cell viability in FGFR1-amplified breast cancer cells. •FGFR1 antagonist induces autophagy in FGFR1-amplified breast cancer cells. •FGFR1 antagonist-induced autophagy is protective. •FGFR1 antagonist induces autophagy by inhibiting Akt/mTOR pathway.

A novel thromboxane receptor antagonist, nstpbp5185, inhibits platelet aggregation and thrombus formation in animal models.

Science.gov (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

2016-08-01

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.

Adenylate cyclase regulates elongation of mammalian primary cilia

International Nuclear Information System (INIS)

Ou, Young; Ruan, Yibing; Cheng, Min; Moser, Joanna J.; Rattner, Jerome B.; Hoorn, Frans A. van der

2009-01-01

The primary cilium is a non-motile microtubule-based structure that shares many similarities with the structures of flagella and motile cilia. It is well known that the length of flagella is under stringent control, but it is not known whether this is true for primary cilia. In this study, we found that the length of primary cilia in fibroblast-like synoviocytes, either in log phase culture or in quiescent state, was confined within a range. However, when lithium was added to the culture to a final concentration of 100 mM, primary cilia of synoviocytes grew beyond this range, elongating to a length that was on average approximately 3 times the length of untreated cilia. Lithium is a drug approved for treating bipolar disorder. We dissected the molecular targets of this drug, and observed that inhibition of adenylate cyclase III (ACIII) by specific inhibitors mimicked the effects of lithium on primary cilium elongation. Inhibition of GSK-3β by four different inhibitors did not induce primary cilia elongation. ACIII was found in primary cilia of a variety of cell types, and lithium treatment of these cell types led to their cilium elongation. Further, we demonstrate that different cell types displayed distinct sensitivities to the lithium treatment. However, in all cases examined primary cilia elongated as a result of lithium treatment. In particular, two neuronal cell types, rat PC-12 adrenal medulla cells and human astrocytes, developed long primary cilia when lithium was used at or close to the therapeutic relevant concentration (1-2 mM). These results suggest that the length of primary cilia is controlled, at least in part, by the ACIII-cAMP signaling pathway.

Adenylate cyclase regulates elongation of mammalian primary cilia

Energy Technology Data Exchange (ETDEWEB)

Ou, Young; Ruan, Yibing; Cheng, Min; Moser, Joanna J. [Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1 (Canada); Rattner, Jerome B. [Department of Cell Biology and Anatomy, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1 (Canada); Hoorn, Frans A. van der, E-mail: fvdhoorn@ucalgary.ca [Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1 (Canada)

2009-10-01

The primary cilium is a non-motile microtubule-based structure that shares many similarities with the structures of flagella and motile cilia. It is well known that the length of flagella is under stringent control, but it is not known whether this is true for primary cilia. In this study, we found that the length of primary cilia in fibroblast-like synoviocytes, either in log phase culture or in quiescent state, was confined within a range. However, when lithium was added to the culture to a final concentration of 100 mM, primary cilia of synoviocytes grew beyond this range, elongating to a length that was on average approximately 3 times the length of untreated cilia. Lithium is a drug approved for treating bipolar disorder. We dissected the molecular targets of this drug, and observed that inhibition of adenylate cyclase III (ACIII) by specific inhibitors mimicked the effects of lithium on primary cilium elongation. Inhibition of GSK-3{beta} by four different inhibitors did not induce primary cilia elongation. ACIII was found in primary cilia of a variety of cell types, and lithium treatment of these cell types led to their cilium elongation. Further, we demonstrate that different cell types displayed distinct sensitivities to the lithium treatment. However, in all cases examined primary cilia elongated as a result of lithium treatment. In particular, two neuronal cell types, rat PC-12 adrenal medulla cells and human astrocytes, developed long primary cilia when lithium was used at or close to the therapeutic relevant concentration (1-2 mM). These results suggest that the length of primary cilia is controlled, at least in part, by the ACIII-cAMP signaling pathway.

Adenylate cyclase toxin-hemolysin relevance for pertussis vaccines

Czech Academy of Sciences Publication Activity Database

Šebo, Peter; Osička, Radim; Mašín, Jiří

2014-01-01

Roč. 13, č. 10 (2014), s. 1215-1227 ISSN 1476-0584 R&D Projects: GA ČR GA13-14547S; GA ČR(CZ) GAP302/11/0580; GA ČR GAP302/12/0460 Institutional support: RVO:61388971 Keywords : adenylate cyclase toxin * antigen delivery * Bordetella pertussis Subject RIV: EE - Microbiology, Virology Impact factor: 4.210, year: 2014

Activation of the pacidamycin PacL adenylation domain by MbtH-like proteins.

Science.gov (United States)

Zhang, Wenjun; Heemstra, John R; Walsh, Christopher T; Imker, Heidi J

2010-11-23

Nonribosomal peptide synthetase (NRPS) assembly lines are major avenues for the biosynthesis of a vast array of peptidyl natural products. Several hundred bacterial NRPS gene clusters contain a small (∼70-residue) protein belonging to the MbtH family for which no function has been defined. Here we show that two strictly conserved Trp residues in MbtH-like proteins contribute to stimulation of amino acid adenylation in some NRPS modules. We also demonstrate that adenylation can be stimulated not only by cognate MbtH-like proteins but also by homologues from disparate natural product pathways.

Thyroid-stimulating immunoglobulins in Hashimoto's thyroiditis measured by radioreceptor assay and adenylate cyclase stimulation and their relationship to HLA-D alleles

Energy Technology Data Exchange (ETDEWEB)

Bliddal, H. (Frederiksberg Hospital, Copenhagen, Denmark); Bech, K.; Feldt-Rasmussen, U.; Thomsen, M.; Ryder, L.P.; Hansen, J.M.; Siersbaek-Nielsen, K.; Friis, T.

1982-11-01

The relationship between thyroid-stimulating immunoglobulins, measured by both radioreceptor assay and adenylate cyclase stimulation, and the HLA alleles was studied in 41 patients with Hashimoto's thyroiditis. TSH binding-inhibiting immunoglobulins (TBII) were detected in 9 (22%) patients, and human thyroid adenylate cyclase-stimulating immunoglobulins (HTACS) were found in 21 (51%) patients. Only 2 patients were positive in both assays, and an inverse relationship was observed between TBII and HTACS. In the 21 HTACS-positive patients, HLA-Dw5 was found in 1 subject, compared to 8 of the 20 HTACS-negative patients (P < 0.01), while 4 of the 9 TBII-positive patients had HLA-Dw5 compared to 5 of the 32 TBII-negative subjects (P = 0.09).No significant relations were observed between the presence of HTACS or TBII and HLA-Dw3 or HLA-B8. It is concluded that TBII and HTACS are produced independently in Hashimoto's thyroiditis, and that the production of these autoantibodies seems to be related to the HLA-D region in this disease.

Age-associated alterations in hepatic β-adrenergic receptor/adenylate cyclase complex

International Nuclear Information System (INIS)

Graham, S.M.; Herring, P.A.; Arinze, I.J.

1987-01-01

The effect of age on catecholamine regulation of hepatic glycogenolysis and on hepatic adenylate cyclase was studied in male rats up to 24 mo of age. Epinephrine and norepinephrine stimulated glycogenolysis in isolated hepatocytes at all age groups studied. Isoproterenol, however, stimulated glycogenolysis only at 24 mo. In isolated liver membranes, usual activators of adenylate cyclase increased the activity of the enzyme considerably more in membranes from 24-mo-old rats than in membranes from either 3- or 22-mo-old rats. The Mn 2+ -dependent activity of the cyclase was increased by 2.9-fold in 3-mo-old animals and ∼ 5.7-fold in 24-mo-old rats, indicating a substantial age-dependent increase in the intrinsic activity of the catalytic unit. The density of the β-adrenergic receptor, as measured by the binding of [ 125 I]-iodocyanopindolol to plasma membranes, was 5-8 fmol/mg protein in rats aged 3-12 mo but increased to 19 fmol/mg protein in 24-mo-old rats. Computer-aided analysis of isoproterenol competition of the binding indicated a small age-dependent increase in the proportion of β-receptors in the high-affinity state. These observations suggest that β-receptor-mediated hepatic glycogenolysis in the aged rat is predicated upon increases in the density of β-receptors as well as increased intrinsic activity of the catalytic unit of adenylate cyclase

Adrenergic receptors inhibit TRPV1 activity in the dorsal root ganglion neurons of rats.

Science.gov (United States)

Matsushita, Yumi; Manabe, Miki; Kitamura, Naoki; Shibuya, Izumi

2018-01-01

Transient receptor potential vanilloid type 1 (TRPV1) is a polymodal receptor channel that responds to multiple types of stimuli, such as heat, acid, mechanical pressure and some vanilloids. Capsaicin is the most commonly used vanilloid to stimulate TRPV1. TRPV1 channels are expressed in dorsal root ganglion neurons that extend to Aδ- and C-fibers and have a role in the transduction of noxious inputs to the skin into the electrical signals of the sensory nerve. Although noradrenergic nervous systems, including the descending antinociceptive system and the sympathetic nervous system, are known to modulate pain sensation, the functional association between TRPV1 and noradrenaline in primary sensory neurons has rarely been examined. In the present study, we examined the effects of noradrenaline on capsaicin-evoked currents in cultured dorsal root ganglion neurons of the rat by the whole-cell voltage clamp method. Noradrenaline at concentrations higher than 0.1 pM significantly reduced the amplitudes of the inward capsaicin currents recorded at -60 mV holding potential. This inhibitory action was reversed by either yohimbine (an α2 antagonist, 10 nM) or propranolol (a β antagonist, 10 nM). The α2 agonists, clonidine (1 pM) and dexmedetomidine (1 pM) inhibited capsaicin currents, and yohimbine (1 nM) reversed the effects of clonidine. The inhibitory action of noradrenaline was not seen in the neurons pretreated with pertussis toxin (100 μg/ml for 24 h) and the neurons dialyzed intracellularly with guanosine 5'- [β-thio] diphosphate (GDPβS, 200 μM), the catalytic subunit of protein kinase A (250 U/ml) or okadaic acid (1 μM). These results suggest that noradrenaline directly acts on dorsal root ganglion neurons to inhibit the activity of TRPV1 depending on the activation of α2-adrenoceptors followed by the inhibition of the adenylate cyclase/cAMP/protein kinase A pathway.

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

2013-01-01

B1 targeting peptide, termed Herfin-1, was designed based on a model of the tertiary structure of the EGF-EGFR ternary complex. The binding kinetics of this peptide were determined employing surface plasmon resonance analyses. ErbB1-4 expression and phosphorylation in human glioblastoma cell lines U...... processing. RESULTS: The present study shows that Herfin-1 functions as an ErbB1 antagonist. It binds to the extracellular domain of ErbB1 with a KD value of 361 nM. In U87 and U118 cells, both expressing high levels of ErbB1, Herfin-1 inhibits EGF-induced ErbB1 phosphorylation and cell migration....... Additionally, Herfin-1 was found to increase neurite outgrowth in cerebellar granule neurons, likely through the inhibition of a sustained weak ErbB1 activation. CONCLUSIONS: Targeting the ErbB1 receptor dimerization interface is a promising strategy to inhibit receptor activation in ErbB1-expressing glioma...

Effects of ionizing radiation and cysteamine (MEA) on activity of mouse spleen adenyl cyclase

International Nuclear Information System (INIS)

Soltysiak-Pawluczuk, D.; Bitny-Szlachto, S.

1976-01-01

In mice X-irradiated with doses of 200 R and 400 R, there was a substantial increase in spleen adenyl cyclase activity; there was similar activation by MEA. In mice given MEA before irradiation, an additive effect of radiation and the radioprotective drug was observed. On the other hand, a dose of 800 R given either alone or after pre-treatment with MEA failed to elicit any change in cyclase activity. The results indicate the importance of the adenyl cyclase system in the response of cells to irradiation and action of MEA. (author)

Regarding the unitary theory of agonist and antagonist action at presynaptic adrenoceptors.

Science.gov (United States)

Kalsner, S; Abdali, S A

2001-06-01

1. The linkage between potentiation of field stimulation-induced noradrenaline release and blockade of the presynaptic inhibitory effect of exogenous noradrenaline by a presynaptic antagonist was examined in superfused rabbit aorta preparations. 2. Rauwolscine clearly potentiated the release of noradrenaline in response to 100 pulses at 2 Hz but reduced the capacity of noradrenaline to inhibit transmitter release to a questionable extent, and then only when comparisons were made with untreated, rather then to rauwolscine-treated, controls. 3. Aortic preparations exposed for 60 min to rauwolscine followed by superfusion with antagonist-free Krebs for 60 min retained the potentiation of stimulation-induced transmitter release but no antagonism of the noradrenaline-induced inhibition could be detected at either of two noradrenaline concentrations when comparisons were made with rauwolscine treated controls. 4. Comparisons of the inhibitory effect of exogenous noradrenaline (1.8 x 10-6 M) on transmitter efflux in the presence and absence of rauwolscine pretreatment revealed that the antagonist enhanced rather than antagonized the presynaptic inhibition by noradrenaline. 5 It is concluded that the unitary hypothesis that asserts that antagonist enhancement of transmitter release and its blockade of noradrenaline induced inhibition are manifestations of a unitary event are not supportable.

Modulation of receptors and adenylate cyclase activity during sucrose feeding, food deprivation, and cold exposure

International Nuclear Information System (INIS)

Scarpace, P.J.; Baresi, L.A.; Morley, J.E.

1987-01-01

Thermogenesis in brown adipose tissue (BAT) serves as a regulator of body temperature and weight maintenance. Thermogenesis can be stimulated by catecholamine activation of adenylate cyclase through the β-adrenergic receptor. To investigate the effects of sucrose feeding, food deprivation, and cold exposure on the β-adrenergic pathway, adenylate cyclase activity and β-adrenergic receptors were assessed in rat BAT after 2 wk of sucrose feeding, 2 days of food deprivation, or 2 days of cold exposure. β-Adrenergic receptors were identified in BAT using [ 125 I]iodocyanopindolol. Binding sites had the characteristics of mixed β 1 - and β 2 -type adrenergic receptors at a ratio of 60/40. After sucrose feeding or cold exposure, there was the expected increase in BAT mitochondrial mass as measured by total cytochrome-c oxidase activity but a decrease in β-adrenergic receptor density due to a loss of the β 1 -adrenergic subtype. This BAT β-adrenergic receptor downregulation was tissue specific, since myocardial β-adrenergic receptors were unchanged with either sucrose feeding or cold exposure. Forskolin-stimulated adenylate cyclase activity increased in BAT after sucrose feeding or cold exposure but not after food deprivation. These data suggest that in BAT, sucrose feeding or cold exposure result in downregulation of β-adrenergic receptors and that isoproterenol-stimulated adenylate cyclase activity was limited by receptor availability

A comprehensive survey of 3′ animal miRNA modification events and a possible role for 3′ adenylation in modulating miRNA targeting effectiveness

OpenAIRE

Burroughs, A. Maxwell; Ando, Yoshinari; de Hoon, Michiel J.L.; Tomaru, Yasuhiro; Nishibu, Takahiro; Ukekawa, Ryo; Funakoshi, Taku; Kurokawa, Tsutomu; Suzuki, Harukazu; Hayashizaki, Yoshihide; Daub, Carsten O.

2010-01-01

Animal microRNA sequences are subject to 3′ nucleotide addition. Through detailed analysis of deep-sequenced short RNA data sets, we show adenylation and uridylation of miRNA is globally present and conserved across Drosophila and vertebrates. To better understand 3′ adenylation function, we deep-sequenced RNA after knockdown of nucleotidyltransferase enzymes. The PAPD4 nucleotidyltransferase adenylates a wide range of miRNA loci, but adenylation does not appear to affect miRNA stability on a...

Carbobenzoxy amino acids: Structural requirements for cholecystokinin receptor antagonist activity

International Nuclear Information System (INIS)

Maton, P.N.; Sutliff, V.E.; Jensen, R.T.; Gardner, J.D.

1985-01-01

The authors used dispersed acini prepared from guinea pig pancreas to examine 28 carbobenzoxy (CBZ) amino acids for their abilities to function as cholecystokinin receptor antagonists. All amino acid derivatives tested, except for CBZ-alanine, CBZ-glycine, and N alpha-CBZ- lysine, were able to inhibit the stimulation of amylase secretion caused by the C-terminal octapeptide of cholecystokinin. In general, there was a good correlation between the ability of a carbobenzoxy amino acid to inhibit stimulated amylase secretion and the ability of the amino acid derivative to inhibit binding of 125 I-cholecystokinin. The inhibition of cholecystokinin-stimulated amylase secretion was competitive, fully reversible, and specific for those secretagogues that interact with the cholecystokinin receptor. The potencies with which the various carbobenzoxy amino acids inhibited the action of cholecystokinin varied 100-fold and CBZ-cystine was the most potent cholecystokinin receptor antagonist. This variation in potency was primarily but not exclusively a function of the hydrophobicity of the amino acid side chain

Regulation of the beta-adrenergic receptor-adenylate cyclase complex of 3T3-L1 fibroblasts by sodium butyrate

International Nuclear Information System (INIS)

Stadel, J.M.; Poksay, K.S.; Nakada, M.T.; Crooke, S.T.

1986-01-01

Mouse 3T3-L1 fibroblasts contain beta-adrenergic receptors (BAR), predominantly of the B 1 subtype. Incubation of these cells with 2-10 mM sodium butyrate (SB) for 24-48 hr results in a switch in the BAR subtype from B 1 to B 2 and promotes a 1.5 to 2.5 fold increase in total BAR number. Other short chain acids were not as effective as SB in promoting changes in BAR. BAR were assayed in membranes prepared from the 3T3-L1 cells using the radiolabeled antagonist [ 125 I]-cyanopindolol and the B 2 selective antagonist ICI 118.551. BAR subtype switch was confirmed functionally by measuring cellular cAMP accumulation in response to agonists. The structure and amount of the alpha subunits of the guanine nucleotide regulatory proteins N/sub s/ and N/sub i/ were determined by ADP-ribosylation using 32 P-NAD and either cholera toxin or pertussis toxin for labeling of the respective subunits. Preincubation of cells with 5 mM SB for 48 hr resulted in a 2-3 fold increase in the labeling of the alpha subunits of both N/sub s/ and N/sub i/. A protein of M/sub r/ = 44,000 showed enhanced labeling by cholera toxin following SB treatment of the cells. These data indicate SB concomitantly regulates expression of BAR subtype and components of the adenylate cyclase in 3T3-L1 cells

Adenylate kinase amplification of ATP bioluminescence for hygiene monitoring in the food and beverage industry.

Science.gov (United States)

Corbitt, A J; Bennion, N; Forsythe, S J

2000-06-01

Fourteen food residues, Escherichia coli O157:H7 and Staphylococcus aureus on stainless steel surfaces were detected using a combined assay with adenylate kinase as a cellular marker and ATP bioluminescence. The limit of sensitivity ranged from 0.02 to 708 microg for minced meat and broccoli, respectively. Both methods gave the same detection limit (105 cfu) for E. coli and Staph. aureus on stainless steel surfaces. The combined adenylate kinase-ATP assay is applicable to monitor the hygiene of work surfaces, especially those prone to contamination by meat and vegetable residues.

Antagonistic studies and hyphal interactions of the new antagonist Aspergillus piperis against some phytopathogenic fungi in vitro in comparison with Trichoderma harzianum.

Science.gov (United States)

El-Debaiky, Samah A

2017-12-01

The present study represents, for the first time, the detailed studies about the hyphal interactions of Aspergillus piperis, as a new antagonist, against some isolated plant pathogenic fungi (Alternaria alternata, Alternaria solani, Botrytis cinerea, Sclerotium cepivorum and Sclerotinia sclerotiorum) in vitro. The bio-controlling capability of A. piperis against the tested phytopathogens was tested using the dual culture method. This experiment revealed that A. piperis had antagonistic activity and reduced the growth of the tested phytopathogens and grew over their mycelia in the paired plates. Also, several antagonistic mechanisms were recorded, in this study, between A. piperis and the tested phytopathogens using the microscopic examination. The bio-controlling activity and the antagonistic mechanisms exhibited by the new antagonist, A. piperis were compared with those obtained by the common antagonist, Trichoderma harzianum against the same phytopathogens. The obtained results showed that, A. piperis was more effective than T. harzianum in inhibiting all the tested species in the dual culture plates. The best result was 81.85% inhibition percentage against S. sclerotiorum by A. piperis while, T. harzianum exhibits only 45.18%. Moreover, several antagonistic mechanisms and hyphal interactions were investigated among the hyphae of both A.piperis and T. harzianum and the hyphae of the tested phytopathogens. These mechanisms were summarized as; mycoparasitism (coiling and penetration of the hyphae) and antibiosis in the form of lysis of the hyphal cells and spores, denaturation and breaking of the hyphae. The indirect interaction (antibiosis) and the direct mycoparasitism were observed by A. piperis against all the tested phytopathogens, but it attacked the hyphae and conidiophores of A. alternata by only the antibiosis interaction. The microscopic examination revealed also that T. harzianum attacked the tested phytopathogens by both antibiosis and mycoparasitism

Pituitary Adenylate Cyclase-Activating Polypeptide Disrupts Motivation, Social Interaction, and Attention in Male Sprague Dawley Rats.

Science.gov (United States)

Donahue, Rachel J; Venkataraman, Archana; Carroll, F Ivy; Meloni, Edward G; Carlezon, William A

2016-12-15

Severe or prolonged stress can trigger psychiatric illnesses including mood and anxiety disorders. Recent work indicates that pituitary adenylate cyclase-activating polypeptide (PACAP) plays an important role in regulating stress effects. In rodents, exogenous PACAP administration can produce persistent elevations in the acoustic startle response, which may reflect anxiety-like signs including hypervigilance. We investigated whether PACAP causes acute or persistent alterations in behaviors that reflect other core features of mood and anxiety disorders (motivation, social interaction, and attention). Using male Sprague Dawley rats, we examined if PACAP (.25-1.0 µg, intracerebroventricular infusion) affects motivation as measured in the intracranial self-stimulation test. We also examined if PACAP alters interactions with a conspecific in the social interaction test. Finally, we examined if PACAP affects performance in the 5-choice serial reaction time task, which quantifies attention and error processing. Dose-dependent disruptions in motivation, social interaction, and attention were produced by PACAP, as reflected by increases in reward thresholds, decreases in social behaviors, and decreases in correct responses and alterations in posterror accuracy. Behavior normalized quickly in the intracranial self-stimulation and 5-choice serial reaction time task tests but remained dysregulated in the social interaction test. Effects on attention were attenuated by the corticotropin-releasing factor receptor-1 antagonist antalarmin but not the κ opioid receptor antagonist JDTic. Our findings suggest that PACAP affects numerous domains often dysregulated in mood and anxiety disorders, but that individual signs depend on brain substrates that are at least partially independent. This work may help to devise therapeutics that mitigate specific signs of these disorders. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

The fungus-growing termite Macrotermes natalensis harbors bacillaene-producing Bacillus sp. that inhibit potentially antagonistic fungi

DEFF Research Database (Denmark)

Um, Soohyun; Fraimout, Antoine; Sapountzis, Panagiotis

2013-01-01

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......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...

Inhibition of Ebola and Marburg Virus Entry by G Protein-Coupled Receptor Antagonists.

Science.gov (United States)

Cheng, Han; Lear-Rooney, Calli M; Johansen, Lisa; Varhegyi, Elizabeth; Chen, Zheng W; Olinger, Gene G; Rong, Lijun

2015-10-01

Filoviruses, consisting of Ebola virus (EBOV) and Marburg virus (MARV), are among the most lethal infectious threats to mankind. Infections by these viruses can cause severe hemorrhagic fevers in humans and nonhuman primates with high mortality rates. Since there is currently no vaccine or antiviral therapy approved for humans, there is an urgent need to develop prophylactic and therapeutic options for use during filoviral outbreaks and bioterrorist attacks. One of the ideal targets against filoviral infection and diseases is at the entry step, which is mediated by the filoviral glycoprotein (GP). In this report, we screened a chemical library of small molecules and identified numerous inhibitors, which are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs, including histamine receptors, 5-HT (serotonin) receptors, muscarinic acetylcholine receptor, and adrenergic receptor. These inhibitors can effectively block replication of both infectious EBOV and MARV, indicating a broad antiviral activity of the GPCR antagonists. The time-of-addition experiment and microscopic studies suggest that GPCR antagonists block filoviral entry at a step following the initial attachment but prior to viral/cell membrane fusion. These results strongly suggest that GPCRs play a critical role in filoviral entry and GPCR antagonists can be developed as an effective anti-EBOV/MARV therapy. Infection of Ebola virus and Marburg virus can cause severe illness in humans with a high mortality rate, and currently there is no FDA-approved vaccine or therapeutic treatment available. The 2013-2015 epidemic in West Africa underscores a lack of our understanding in the infection and pathogenesis of these viruses and the urgency of drug discovery and development. In this study, we have identified numerous inhibitors that are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs. These inhibitors can effectively block replication of both infectious

Assay method for organic calcium antagonist drugs and a kit for such an assay

International Nuclear Information System (INIS)

Snyder, S. H.; Gould, R. J.

1985-01-01

A method for measuring the level of organic calcium antagonist drug in a body fluid comprises preparing a mixture of a radioactive calcium antagonist drug, a body fluid containing a calcium antagonist drug and a calcium antagonist receptor material, measuring the radioactivity of the radioactive calcium antagonist drug bound to said calcium antagonist receptor material and deriving the concentration of the calcium antagonist drug in the body fluid from a standard curve indicating the concentration of calcium antagonist drug versus inhibition of binding of said radioactive calcium antagonist drug to said receptor sites caused by the calcium antagonist drug in said body fluid. A kit for measuring the level of an organic calcium drug comprises a receptacle containing a radioactive calcium antagonist drug, a calcium antagonist receptor material and a standard amount of a nonradioactive calcium antagonist drug

Inhibition of growth of experimental prostate cancer with sustained delivery systems (microcapsules and microgranules) of the luteinizing hormone-releasing hormone antagonist SB-75.

Science.gov (United States)

Korkut, E; Bokser, L; Comaru-Schally, A M; Groot, K; Schally, A V

1991-02-01

Inhibitory effects of the sustained delivery systems (microcapsules and microgranules) of a potent antagonist of luteinizing hormone-releasing hormone N-Ac-[3-(2-naphthyl)-D-alanine1, 4-chloro-D-phenylalanine2, 3-(3-pyridyl)-D-alanine3, D-citrulline6, D-alanine10]LH-RH (SB-75) on the growth of experimental prostate cancers were investigated. In the first experiment, three doses of a microcapsule preparation releasing 23.8, 47.6, and 71.4 micrograms of antagonist SB-75 per day were compared with microcapsules of agonist [D-Trp6]LH-RH liberating 25 micrograms/day in rats bearing Dunning R3327H transplantable prostate carcinoma. During 8 weeks of treatment, tumor growth was decreased by [D-Trp6]LH-RH and all three doses of SB-75 as compared to untreated controls. The highest dose of SB-75 (71.4 micrograms/day) caused a greater inhibition of prostate cancer growth than [D-Trp6]LH-RH as based on measurement of tumor volume and percentage change in tumor volume. Doses of 23.8 and 47.6 micrograms of SB-75 per day induced a partial and submaximal decrease, respectively, in tumor weight and volume. Tumor doubling time was the longest (50 days) with the high dose of SB-75 vs. 15 days for controls. The body weights were unchanged. The weights of testes, seminal vesicles, and ventral prostate were greatly reduced in all three groups that received SB-75, and testosterone levels were decreased to nondetectable values in the case of the two higher doses of SB-75. LH levels were also diminished. Similar results were obtained in the second experiment, in which the animals were treated for a period of 8 weeks with microgranules of SB-75. Therapy with microgranules of SB-75 significantly decreased tumor growth as measured by the final tumor volume, the percentage change from the initial tumor volume, and the reduction in tumor weight. The results indicate that antagonist SB-75, released from sustained delivery systems, can produce a state of chemical castration and effectively

Human adenylate kinases – classification, structure, physiological and pathological importance

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Magdalena Wujak

2015-01-01

Full Text Available Adenylate kinase (AK, EC 2.7.4.3 is a ubiquitous phosphotransferase which catalyzes the reversible transfer of high-energy β – and γ-phosphate groups between nucleotides. All classified AKs show a similar structure: they contain a large central CORE region, nucleoside monophosphate and triphosphate binding domains (NMPbd and NTPbd and the LID domain. Analysis of amino acid sequence similarity revealed the presence of as many as nine human AK isoenzymes, which demonstrate different organ-tissue and intercellular localization. Among these kinases, only two, AK1 and AK2, fulfill the structural and functional criterion by the highest affinity for adenine nucleotides and the utilization of only AMP or dAMP as phosphate acceptors. Human AK isoenzymes are involved in nucleotide homeostasis and monitor disturbances of cell energy charge. Participating in large regulatory protein complexes, AK supplies high energy substrates for controlling the functions of channels and transporters as well as ligands for extracellular P2 nucleotide receptors. In pathological conditions AK can take over the function of other kinases, such as creatine kinase in oxygen-depleted myocardium. Directed mutagenesis and genetic studies of diseases (such as aleukocytosis, hemolytic anemia, primary ciliary dyskinesia (PCD link the presence and activity of AK with etiology of these disturbances. Moreover, AK participates in regulation of differentiation and maturation of cells as well as in apoptosis and oncogenesis. Involvement of AK in a wide range of processes and the correlation between AK and etiology of diseases support the medical potential for the use of adenylate kinases in the diagnosis and treatment of certain diseases. This paper summarizes the current knowledge on the structure, properties and functions of human adenylate kinase.

Neuromodulation of reciprocal glutamatergic inhibition between antagonistic motoneurons by 5-hydroxytryptamine (5-HT) in crayfish walking system.

Science.gov (United States)

Pearlstein, E; Clarac, F; Cattaert, D

1998-01-23

In an in vitro preparation of the crayfish thoracic locomotor system, paired intracellular recordings were performed from antagonistic depressor (Dep) and levator (Lev) motoneurons (MNs) that control the second joint of walking legs. Connections between these two groups of MNs consist mainly of inhibitory connections and weak electrotonic synapses. Injection of depolarizing current into a Lev MN results in a hyperpolarization in a Dep MN, and vice versa. This reciprocal glutamatergic inhibition, is not changed in the presence of the sodium channel blocker tetrodotoxin (TTX) and therefore is likely supported by a direct connection between MNs. By contrast, reciprocal inhibition is largely reduced in the presence of 5-hydroxytryptamine (5-HT; 10 microM). Direct micro-application of glutamate pressure-ejected close to an intracellularly recorded MN, evoked an inhibitory response in that MN, accompanied by a decrease of input resistance. These two effects were dramatically reduced in the presence of 5-HT. Thus 5-HT could be involved in mechanisms of dynamic reconfigurations of the neural network controlling leg movements in crayfish.

Adenylate cyclase regulation in intact cultured myocardial cells

International Nuclear Information System (INIS)

Marsh, J.D.; Roberts, D.J.

1987-01-01

To examine the coupling of cardiac cell-surface β-adrenergic receptors to adenylate cyclase activation and contractile response, the authors studied this receptor-effector response system in monolayers of spontaneously contracting chick embryo ventricular cells under physiological conditions. The hydrophilic ligand 3 H-CGP12177 identified uniformly high-agonist affinity β-adrenergic receptors. Isoproterenol-stimulated cyclic AMP (cAMP) accumulation with 50% effective concentration at (EC 50 ) = 12.1 nM and augmented contractile response with EC 50 = 6 nM under identical conditions. One micromolar isoproterenol induced receptor loss from the cell surface with t/sub 1/2/ = 13.2 min; under identical conditions cAMP content declined with t/sub 1/2/ = 13.5 min and contractile response with t/sub 1/2/ = 20.7 min. After agonist removal cAMP response recovered with t/sub 1/2/ = 15.7 min and receptors with t/sub 1/2/ = 24.7 min. Sixty minutes after agonist removal there was recovery of 52% of maximal cAMP responsiveness and 82% of the initial number of receptors; receptor occupancy was associated with 78% of initial contractile response. Agonist affinity for cell-surface receptors was changed only modestly by agonist exposure. They conclude that for this system there is relatively close coupling between high-affinity receptors, adenylate cyclase stimulation, and contractile response

Irradiation inactivation studies of the dopamine D1 receptor and dopamine-stimulated adenylate cyclase in rat striatum

International Nuclear Information System (INIS)

Anderson, P.H.; Nielson, M.

1987-01-01

In frozen rat striatal tissue, exposed to 10 MeV electrons from a linear accelerator, the sizes of the dopamine (DA) D 1 receptor and the DA sensitive adenylate cyclase complex were determined using target size analysis. The number of D 1 receptors (labelled by [ 3 H]SCH 23390)declined monoexponentially with increasing radiation intensity, yielding a molecular weight (mol. wt.) of 80kDa. Also the activity of the catalytic unit (C) of the adenylate cyclase (as measured by forskolin stimulation), decreased monoexponentially however with a mol. wt. of 145 kDa. Both basal, DA- and flouride (F - ) stimulated activity declined in a concave downward fashion with a limiting mol. wt. of 134, 138 and 228 kDa respectively. It was estimated that the basal and DA - stimulated activity originated from an enzyme complex with a mol. wt. of 325 kDa a value close to the combined size of R G S + C. These data suggest that F - stimulation of the adenylate cyclase, which occurs by a G S activation, does not cause disassociation of G S into the α S and βγ subunits. Further, the AA-regulated adenylate cyclase apparently exists as a complex consisting of RG S and C; the mechanisms of hormonal activation is dissociation of C from this complex

Inhibition of neurotensin-stimulated mast cell secretion and carboxypeptidase A activity by the peptide inhibitor of carboxypeptidase A and neurotensin-receptor antagonist SR 48692.

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Miller, L A; Cochrane, D E; Feldberg, R S; Carraway, R E

1998-06-01

Neurotensin (NT), a peptide found in brain and several peripheral tissues, is a potent stimulus for mast cell secretion and its actions are blocked by the specific NT receptor antagonist, SR 48692. Subsequent to stimulation, NT is rapidly degraded by mast cell carboxypeptidase A (CPA). In the experiments described here, we tested for the involvement of CPA activity in the activation of mast cell secretion by the peptide, NT. Mast cells were isolated from the peritoneal and pleural cavities of rats, purified over metrizamide gradients and incubated at 37 degrees C in Locke solution or Locke containing the appropriate inhibitors. For some experiments, media derived from mast cells stimulated by compound 48/80 were used as a source of mast cell CPA activity. Treatment of mast cells with the highly specific peptide inhibitor of CPA derived from potato (PCI) inhibited histamine release in response to NT and NT8-13 (the biologically active region of NT). This inhibition required some 20 min to develop and was only partially reversed by a 20-min wash period. PCI (10 microM) did not inhibit histamine release in response to NT1-12, bradykinin, compound 48/80, the calcium ionophore, A23187, or anti-IgE serum. PCI also inhibited mast cell CPA activity. SR 48692, a highly selective antagonist of the brain NT receptor and of NT-stimulated mast cell secretion, also inhibited mast cell CPA activity as well as bovine pancreatic CPA activity in a concentration-dependent manner. It is suggested that the mast cell binding site for NT and the active site for CPA may share similar characteristics. The results are discussed in terms of NT mechanism of action on the mast cell.

Construction, purification, and characterization of a chimeric TH1 antagonist

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Javier-González Luís

2006-05-01

Full Text Available Abstract Background TH1 immune response antagonism is a desirable approach to mitigate some autoimmune and inflammatory reactions during the course of several diseases where IL-2 and IFN-γ are two central players. Therefore, the neutralization of both cytokines could provide beneficial effects in patients suffering from autoimmune or inflammatory illnesses. Results A chimeric antagonist that can antagonize the action of TH1 immunity mediators, IFN-γ and IL-2, was designed, engineered, expressed in E. coli, purified and evaluated for its in vitro biological activities. The TH1 antagonist molecule consists of the extracellular region for the human IFNγ receptor chain 1 fused by a four-aminoacid linker peptide to human 60 N-terminal aminoacid residues of IL-2. The corresponding gene fragments were isolated by RT-PCR and cloned in the pTPV-1 vector. E. coli (W3110 strain was transformed with this vector. The chimeric protein was expressed at high level as inclusion bodies. The protein was partially purified by pelleting and washing. It was then solubilized with strong denaturant and finally refolded by gel filtration. In vitro biological activity of chimera was demonstrated by inhibition of IFN-γ-dependent HLA-DR expression in Colo 205 cells, inhibition of IFN-γ antiproliferative effect on HEp-2 cells, and by a bidirectional effect in assays for IL-2 T-cell dependent proliferation: agonism in the absence versus inhibition in the presence of IL-2. Conclusion TH1 antagonist is a chimeric protein that inhibits the in vitro biological activities of human IFN-γ, and is a partial agonist/antagonist of human IL-2. With these attributes, the chimera has the potential to offer a new opportunity for the treatment of autoimmune and inflammatory diseases.

Pituitary adenylate cyclase activating polypeptide (PACAP signalling exerts chondrogenesis promoting and protecting effects: implication of calcineurin as a downstream target.

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Tamás Juhász

Full Text Available Pituitary adenylate cyclase activating polypeptide (PACAP is an important neurotrophic factor influencing differentiation of neuronal elements and exerting protecting role during traumatic injuries or inflammatory processes of the central nervous system. Although increasing evidence is available on its presence and protecting function in various peripheral tissues, little is known about the role of PACAP in formation of skeletal components. To this end, we aimed to map elements of PACAP signalling in developing cartilage under physiological conditions and during oxidative stress. mRNAs of PACAP and its receptors (PAC1,VPAC1, VPAC2 were detectable during differentiation of chicken limb bud-derived chondrogenic cells in micromass cell cultures. Expression of PAC1 protein showed a peak on days of final commitment of chondrogenic cells. Administration of either the PAC1 receptor agonist PACAP 1-38, or PACAP 6-38 that is generally used as a PAC1 antagonist, augmented cartilage formation, stimulated cell proliferation and enhanced PAC1 and Sox9 protein expression. Both variants of PACAP elevated the protein expression and activity of the Ca-calmodulin dependent Ser/Thr protein phosphatase calcineurin. Application of PACAPs failed to rescue cartilage formation when the activity of calcineurin was pharmacologically inhibited with cyclosporine A. Moreover, exogenous PACAPs prevented diminishing of cartilage formation and decrease of calcineurin activity during oxidative stress. As an unexpected phenomenon, PACAP 6-38 elicited similar effects to those of PACAP 1-38, although to a different extent. On the basis of the above results, we propose calcineurin as a downstream target of PACAP signalling in differentiating chondrocytes either in normal or pathophysiological conditions. Our observations imply the therapeutical perspective that PACAP can be applied as a natural agent that may have protecting effect during joint inflammation and/or may promote

Twisted gastrulation, a BMP antagonist, exacerbates podocyte injury.

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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.

The effects of sex and neonatal stress on pituitary adenylate cyclase-activating peptide expression.

Science.gov (United States)

Mosca, E V; Rousseau, J P; Gulemetova, R; Kinkead, R; Wilson, R J A

2015-02-01

What is the central question of this study? Does sex or neonatal stress affect the expression of pituitary adenylate cyclase-activating peptide or its receptors? What is the main finding and its importance? Neonatal-maternal separation stress has little long-lasting effect on the expression of pituitary adenylate cyclase-activating peptide or its receptors, but sex differences exist in these genes between males and females at baseline. Sex differences in classic stress hormones have been studied in depth, but pituitary adenylate cyclase-activating peptide (PACAP), recently identified as playing a critical role in the stress axes, has not. Here we studied whether baseline levels of PACAP differ between sexes in various stress-related tissues and whether neonatal-maternal separation stress has a sex-dependent effect on PACAP gene expression in stress pathways. Using quantitative RT-PCR, we found sex differences in PACAP and PACAP receptor gene expression in several respiratory and/or stress-related tissues, while neonatal-maternal separation stress did little to affect PACAP signalling in adult animals. We propose that sex differences in PACAP expression are likely to contribute to differences between males and females in responses to stress. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

The small-molecule IAP antagonist AT406 inhibits pancreatic cancer cells in vitro and in vivo

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Jiang, Yongsheng; Meng, Qinghua [Department of General Surgery, Jinan Central Hospital of Shandong University, Jinan (China); Chen, Bo [Department of Biliary and Pancreatic Surgery, East Hospital Affiliated to Tongji University in Shanghai, Shanghai (China); Shen, Haiyu; Yan, Bing [Department of General Surgery, Jinan Central Hospital of Shandong University, Jinan (China); Sun, Baoyou, E-mail: sunbaoyou_sdu@yeah.net [Department of General Surgery, Shandong Provincial Hospital Affiliated to Shandong University, No.9677 Jing-Shi Road, Jinan 250014 (China)

2016-09-09

In the present study, we tested the anti-pancreatic cancer activity by AT406, a small-molecule antagonist of IAP (inhibitor of apoptosis proteins). In established (Panc-1 and Mia-PaCa-2 lines) and primary human pancreatic cancer cells, treatment of AT406 significantly inhibited cell survival and proliferation. Yet, same AT406 treatment was non-cytotoxic to pancreatic epithelial HPDE6c7 cells. AT406 increased caspase-3/-9 activity and provoked apoptosis in the pancreatic cancer cells. Reversely, AT406′ cytotoxicity in these cells was largely attenuated with pre-treatment of caspase inhibitors. AT406 treatment caused degradation of IAP family proteins (cIAP1 and XIAP) and release of cytochrome C, leaving Bcl-2 unaffected in pancreatic cancer cells. Bcl-2 inhibition (by ABT-737) or shRNA knockdown dramatically sensitized Panc-1 cells to AT406. In vivo, oral administration of AT406 at well-tolerated doses downregulated IAPs (cIAP1/XIAP) and inhibited Panc-1 xenograft tumor growth in severe combined immunodeficient (SCID) nude mice. Together, our preclinical results suggest that AT406 could be further evaluated as a promising anti-pancreatic cancer agent. - Highlights: • AT406 is cytotoxic to established/primary human pancreatic cancer cells. • AT406 provokes caspase-dependent apoptosis in pancreatic cancer cells. • AT406 causes degradation of key IAPs and promotes cytochrome C release. • Bcl-2 inhibition or knockdown dramatically sensitizes Panc-1 cells to AT406. • Oral administration of AT406 inhibits Panc-1 tumor growth in SCID nude mice.

The small-molecule IAP antagonist AT406 inhibits pancreatic cancer cells in vitro and in vivo

International Nuclear Information System (INIS)

Jiang, Yongsheng; Meng, Qinghua; Chen, Bo; Shen, Haiyu; Yan, Bing; Sun, Baoyou

2016-01-01

In the present study, we tested the anti-pancreatic cancer activity by AT406, a small-molecule antagonist of IAP (inhibitor of apoptosis proteins). In established (Panc-1 and Mia-PaCa-2 lines) and primary human pancreatic cancer cells, treatment of AT406 significantly inhibited cell survival and proliferation. Yet, same AT406 treatment was non-cytotoxic to pancreatic epithelial HPDE6c7 cells. AT406 increased caspase-3/-9 activity and provoked apoptosis in the pancreatic cancer cells. Reversely, AT406′ cytotoxicity in these cells was largely attenuated with pre-treatment of caspase inhibitors. AT406 treatment caused degradation of IAP family proteins (cIAP1 and XIAP) and release of cytochrome C, leaving Bcl-2 unaffected in pancreatic cancer cells. Bcl-2 inhibition (by ABT-737) or shRNA knockdown dramatically sensitized Panc-1 cells to AT406. In vivo, oral administration of AT406 at well-tolerated doses downregulated IAPs (cIAP1/XIAP) and inhibited Panc-1 xenograft tumor growth in severe combined immunodeficient (SCID) nude mice. Together, our preclinical results suggest that AT406 could be further evaluated as a promising anti-pancreatic cancer agent. - Highlights: • AT406 is cytotoxic to established/primary human pancreatic cancer cells. • AT406 provokes caspase-dependent apoptosis in pancreatic cancer cells. • AT406 causes degradation of key IAPs and promotes cytochrome C release. • Bcl-2 inhibition or knockdown dramatically sensitizes Panc-1 cells to AT406. • Oral administration of AT406 inhibits Panc-1 tumor growth in SCID nude mice.

Antagonist Anti-CD28 Therapeutics for the Treatment of Autoimmune Disorders

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Bernard Vanhove

2017-11-01

Full Text Available The effector functions of T lymphocytes are responsible for most autoimmune disorders and act by directly damaging tissues or by indirectly promoting inflammation and antibody responses. Co-stimulatory and co-inhibitory T cell receptor molecules are the primary pharmacological targets that enable interference with immune-mediated diseases. Among these, selective CD28 antagonists have drawn special interest, since they tip the co-stimulation/co-inhibition balance towards efficiently inhibiting effector T cells while promoting suppression by pre-existing regulatory T-cells. After having demonstrated outstanding therapeutic efficacy in multiple models of autoimmunity, inflammation and transplantation, and safety in phase-I studies in humans, selective CD28 antagonists are currently in early clinical development for the treatment of systemic lupus erythematous and rheumatoid arthritis. Here, we review the available proof of concept studies for CD28 antagonists in autoimmunity, with a special focus on the mechanisms of action.

Antagonistic properties of microogranisms associated with cassava ...

African Journals Online (AJOL)

The antagonistic properties of indigenous microflora from cassava starch, flour and grated cassava were investigated using the conventional streak, novel ring and well diffusion methods. Antagonism was measured by zone of inhibition between the fungal plug and bacterial streak/ring. Bacillus species were more effective ...

A comprehensive survey of 3' animal miRNA modification events and a possible role for 3' adenylation in modulating miRNA targeting effectiveness.

Science.gov (United States)

Burroughs, A Maxwell; Ando, Yoshinari; de Hoon, Michiel J L; Tomaru, Yasuhiro; Nishibu, Takahiro; Ukekawa, Ryo; Funakoshi, Taku; Kurokawa, Tsutomu; Suzuki, Harukazu; Hayashizaki, Yoshihide; Daub, Carsten O

2010-10-01

Animal microRNA sequences are subject to 3' nucleotide addition. Through detailed analysis of deep-sequenced short RNA data sets, we show adenylation and uridylation of miRNA is globally present and conserved across Drosophila and vertebrates. To better understand 3' adenylation function, we deep-sequenced RNA after knockdown of nucleotidyltransferase enzymes. The PAPD4 nucleotidyltransferase adenylates a wide range of miRNA loci, but adenylation does not appear to affect miRNA stability on a genome-wide scale. Adenine addition appears to reduce effectiveness of miRNA targeting of mRNA transcripts while deep-sequencing of RNA bound to immunoprecipitated Argonaute (AGO) subfamily proteins EIF2C1-EIF2C3 revealed substantial reduction of adenine addition in miRNA associated with EIF2C2 and EIF2C3. Our findings show 3' addition events are widespread and conserved across animals, PAPD4 is a primary miRNA adenylating enzyme, and suggest a role for 3' adenine addition in modulating miRNA effectiveness, possibly through interfering with incorporation into the RNA-induced silencing complex (RISC), a regulatory role that would complement the role of miRNA uridylation in blocking DICER1 uptake.

Inhibition of deprivation-induced food intake by GABA(A) antagonists: roles of the hypothalamic, endocrine and alimentary mechanisms.

Science.gov (United States)

Kamatchi, Ganesan L; Rathanaswami, Palaniswami

2012-07-01

The role of gamma amino butyric acid A receptors/neurons of the hypothalamic, endocrine and alimentary systems in the food intake seen in hunger was studied in 20 h food-deprived rats. Food deprivation decreased blood glucose, serum insulin and produced hyperphagia. The hyperphagia was inhibited by subcutaneous or ventromedial hypothalamic administration of gamma amino butyric acid A antagonists picrotoxin or bicuculline. Although results of blood glucose was variable, insulin level was increased by picrotoxin or bicuculline. In contrast, lateral hypothalamic administration of these agents failed to reproduce the above changes. Subcutaneous administration of picrotoxin or bicuculline increased gastric content, decreased gastric motility and small bowel transit. In contrast, ventromedial or lateral hypothalamic administration of picrotoxin or bicuculline failed to alter the gastric content but decreased the small bowel transit. The results of alimentary studies suggest that gamma amino butyric acid neurons of both ventromedial and lateral hypothalamus selectively regulate small bowel transit but not the gastric content. It may be concluded that ventromedial hypothalamus plays a dominant role in the regulation of food intake and that picrotoxin or bicuculline inhibited food intake by inhibiting gamma amino butyric acid receptors of the ventromedial hypothalamus, increasing insulin level and decreasing the gut motility.

Mesophilic and hyperthermophilic adenylate kinases differ in their tolerance to random fragmentation.

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Segall-Shapiro, Thomas H; Nguyen, Peter Q; Dos Santos, Edgardo D; Subedi, Saurav; Judd, Justin; Suh, Junghae; Silberg, Jonathan J

2011-02-11

The extent to which thermostability influences the location of protein fragmentation sites that allow retention of function is not known. To evaluate this, we used a novel transposase-based approach to create libraries of vectors that express structurally-related fragments of Bacillus subtilis adenylate kinase (BsAK) and Thermotoga neapolitana adenylate kinase (TnAK) with identical modifications at their termini, and we selected for variants in each library that complement the growth of Escherichia coli with a temperature-sensitive adenylate kinase (AK). Mutants created using the hyperthermophilic TnAK were found to support growth with a higher frequency (44%) than those generated from the mesophilic BsAK (6%), and selected TnAK mutants complemented E. coli growth more strongly than homologous BsAK variants. Sequencing of functional clones from each library also identified a greater dispersion of fragmentation sites within TnAK. Nondisruptive fission sites were observed within the AMP binding and core domains of both AK homologs. However, only TnAK contained sites within the lid domain, which undergoes dynamic fluctuations that are critical for catalysis. These findings implicate the flexible lid domain as having an increased sensitivity to fission events at physiological temperatures. In addition, they provide evidence that comparisons of nondisruptive fission sites in homologous proteins could be useful for finding dynamic regions whose conformational fluctuations are important for function, and they show that the discovery of protein fragments that cooperatively function in mesophiles can be aided by the use of thermophilic enzymes as starting points for protein design. Copyright © 2010 Elsevier Ltd. All rights reserved.

Metabolites produced by antagonistic microbes inhibit the principal avocado pathogens in vitro

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Sara Ramírez R.

2015-04-01

Full Text Available The demand for Hass avocado in the global market exceeds the supply by over 50%. Colombia has a remarkable advantage as a producer in the region due to its high yields. However, the productivity of this crop can be seriously affected by diseases such as root rot, caused by Phytophthora cinnamomi, postharvest body rot and stem end rot, caused by Colletotrichum sp. and Phomopsis sp., respectively. The potential of 76 bacterial isolates obtained from avocado rhizosphere to produce inhibitory metabolites against avocado's pathogens was evaluated. The antagonistic effect of the rhizobacteria against P. cinnamomi, Colletotrichum sp. and Phomopsis sp. was tested through dual cultures. Thirty-six percent of the tested isolates presented inhibition halos against P. cinnamomi, 36% against Colletotrichum sp. and 67% against Phomopsis sp. Additionally, three isolates were selected for fermentation tests using different broth cultures. The extracts obtained from fermentations in the minimal medium of isolates ARP5.1 and AED06 showed inhibitory activity against the evaluated pathogens, but this effect was not observed with the AED26 extract. The media supplemented with copper chloride did not enhance activity of the extracts. These results suggest that using microbial metabolic extracts is a viable alternative for controlling avocado pathogens in vitro.

Low-molecular weight fractions of Japanese soy sauce act as a RAGE antagonist via inhibition of RAGE trafficking to lipid rafts.

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Munesue, Seiichi; Yamamoto, Yasuhiko; Urushihara, Ryouta; Inomata, Kouhei; Saito, Hidehito; Motoyoshi, So; Watanabe, Takuo; Yonekura, Hideto; Yamamoto, Hiroshi

2013-12-01

Advanced glycation end-products (AGE) have been implicated in aging and the pathogenesis of diabetic complications, inflammation, Alzheimer's disease, and cancer. AGE engage the cell surface receptor for AGE (RAGE), which in turn elicits intracellular signaling, leading to activation of NF-κB to cause deterioration of tissue homeostasis. AGE are not only formed within our bodies but are also derived from foods, endowing them with flavor. In the present study, we assessed the agonistic/antagonistic effects of food-derived AGE on RAGE signaling in a reporter assay system and found that low-molecular weight AGE can antagonize the action of AGE-BSA. Foods tested were Japanese soy sauce, coffee, cola, and red wine, all of which showed fluorescence characteristics of AGE. Soy sauce and coffee contained N(ε)-carboxymethyl-lysine (CML). Soy sauce, coffee, and red wine inhibited the RAGE ligand-induced activation of NF-κB, whereas cola had no effect on the ligand induction of NF-κB. The liquids were then fractionated into high-molecular weight (HMW) fractions and low-molecular weight (LMW) fractions. Soy sauce-, coffee-, and red wine-derived LMW fractions consistently inhibited the RAGE ligand induction of NF-κB, whereas the HMW fractions of these foods activated RAGE signaling. Using the LMW fraction of soy sauce as a model food-derived RAGE antagonist, we performed a plate-binding assay and found that the soy sauce LMW fractions competitively inhibited AGE-RAGE association. Further, this fraction significantly reduced AGE-dependent monocyte chemoattractant protein-1 (MCP-1) secretion from murine peritoneal macrophages. The LMF from soy sauce suppressed the AGE-induced RAGE trafficking to lipid rafts. These results indicate that small components in some, if not all, foods antagonize RAGE signaling and could exhibit beneficial effects on RAGE-related diseases.

Identification of ligand-selective peptidic ActRIIB-antagonists using phage display technology

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Kotaro Sakamoto

2017-09-01

Full Text Available ActRIIB (activin receptor type-2B is an activin receptor subtype constitutively expressed in the whole body, playing a role in cellular proliferation, differentiation, and metabolism. For its various physiological activities, ActRIIB interacts with activin and multiple other ligands including myostatin (MSTN, growth differentiation factor 11 (GDF11, and bone morphogenetic protein 9 (BMP9. Notably, the protein-protein interaction (PPI between ActRIIB and MSTN negatively controls muscular development. Therefore, this PPI has been targeted for effective treatment of muscle degenerative diseases such as muscular dystrophy and sarcopenia. Here, we report the identification of ligand-selective peptidic ActRIIB-antagonists by phage display technology. Our peptides bound to the extracellular domain of ActRIIB, inhibited PPIs between ActRIIB expressed on the cell surface and its ligands, and subsequently suppressed activation of Smad that serves as the downstream signal of the ActRIIB pathway. Interestingly, these peptidic antagonists displayed different ligand selectivities; the AR2mini peptide inhibited multiple ligands (activin A, MSTN, GDF11, and BMP9, AR9 inhibited MSTN and GDF11, while AR8 selectively inhibited MSTN. This is the first report of artificial peptidic ActRIIB-antagonists possessing ligand-selectivity.

31P NMR Spectroscopy Revealed Adenylate kinase-like Activity and Phosphotransferase-like Activity from F1-ATPase of Escherichia coli

International Nuclear Information System (INIS)

Kim, Hyun Won

2011-01-01

Adenylate kinase-like activity and phosphotransferase-like activity from F 1 -ATPase of Escherichia coli was revealed by 31 P NMR spectroscopy. Incubation of F 1 -ATPase with ADP in the presence of Mg 2+ shows the appearance of 31 P resonances from AMP and Pi, suggesting generation of AMP and ATP by adenylate kinase-like activity and the subsequent hydrolysis to Pi. Incubation of F1-ATPase with ADP in the presence of methanol shows additional peak from methyl phosphate, suggesting phosphotransferase-like activity of F 1 -ATPase. Both adenylate kinase-like activity and phosphotransferase-like activity has not been reported from F 1 -ATPase of Escherichia coli. 31 P NMR could be a valuable tool for the investigation of phosphorous related enzyme

Drug safety is a barrier to the discovery and development of new androgen receptor antagonists.

Science.gov (United States)

Foster, William R; Car, Bruce D; Shi, Hong; Levesque, Paul C; Obermeier, Mary T; Gan, Jinping; Arezzo, Joseph C; Powlin, Stephanie S; Dinchuk, Joseph E; Balog, Aaron; Salvati, Mark E; Attar, Ricardo M; Gottardis, Marco M

2011-04-01

Androgen receptor (AR) antagonists are part of the standard of care for prostate cancer. Despite the almost inevitable development of resistance in prostate tumors to AR antagonists, no new AR antagonists have been approved for over a decade. Treatment failure is due in part to mutations that increase activity of AR in response to lower ligand concentrations as well as to mutations that result in AR response to a broader range of ligands. The failure to discover new AR antagonists has occurred in the face of continued research; to enable progress, a clear understanding of the reasons for failure is required. Non-clinical drug safety studies and safety pharmacology assays were performed on previously approved AR antagonists (bicalutamide, flutamide, nilutamide), next generation antagonists in clinical testing (MDV3100, BMS-641988), and a pre-clinical drug candidate (BMS-501949). In addition, non-clinical studies with AR mutant mice, and EEG recordings in rats were performed. Non-clinical findings are compared to disclosures of clinical trial results. As a drug class, AR antagonists cause seizure in animals by an off-target mechanism and are found in vitro to inhibit GABA-A currents. Clinical trials of candidate next generation AR antagonists identify seizure as a clinical safety risk. Non-clinical drug safety profiles of the AR antagonist drug class create a significant barrier to the identification of next generation AR antagonists. GABA-A inhibition is a common off-target activity of approved and next generation AR antagonists potentially explaining some side effects and safety hazards of this class of drugs. Copyright © 2010 Wiley-Liss, Inc.

Inhibition of tumor metastasis by a growth factor receptor bound protein 2 Src homology 2 domain-binding antagonist.

Science.gov (United States)

Giubellino, Alessio; Gao, Yang; Lee, Sunmin; Lee, Min-Jung; Vasselli, James R; Medepalli, Sampath; Trepel, Jane B; Burke, Terrence R; Bottaro, Donald P

2007-07-01

Metastasis, the primary cause of death in most forms of cancer, is a multistep process whereby cells from the primary tumor spread systemically and colonize distant new sites. Blocking critical steps in this process could potentially inhibit tumor metastasis and dramatically improve cancer survival rates; however, our understanding of metastasis at the molecular level is still rudimentary. Growth factor receptor binding protein 2 (Grb2) is a widely expressed adapter protein with roles in epithelial cell growth and morphogenesis, as well as angiogenesis, making it a logical target for anticancer drug development. We have previously shown that a potent antagonist of Grb2 Src homology-2 domain-binding, C90, blocks growth factor-driven cell motility in vitro and angiogenesis in vivo. We now report that C90 inhibits metastasis in vivo in two aggressive tumor models, without affecting primary tumor growth rate. These results support the potential efficacy of this compound in reducing the metastatic spread of primary solid tumors and establish a critical role for Grb2 Src homology-2 domain-mediated interactions in this process.

The Cultivation of Antagonistic Bacteria in Irradiated Sludge for Biological Control of Soft Rot Erwinias : Screening of Antagonistic Bacteria for biological Control of Soft Rot Erwinias

International Nuclear Information System (INIS)

Sermkiattipong, Ng.; Sangsuk, L; Rattanapiriyakul, P; Dejsirilert, S.; Thaveechai, N.

1998-01-01

Pure cultures of 57 bacterial isolates for antagonistic activity screening were isolated from three areas of soft rot infested vegetable soil and 58 isolates were obtained from commercial seed compost and seed compost product of Division of Soil and Water Conservation, Department of Land Development. A total of 115 bacterial isolates were evaluated for antagonizing activity against Erwinia carotovora subsp. atroceptica in vitro. Out of them, 18 isolates were antagonists by showing zone of inhibition ranging from 1 to 17 mm by diameter. Most of antagonistic bacteria were identified as Bacillus spp. whereas only one isolate was Pseudomonas vesicularis

Carbon adaptation influence the antagonistic ability of ...

African Journals Online (AJOL)

Influences of carbon adaptation on antagonistic activities of three Pseudomonas aeruginosa strains V4, V7 and V10 against Fusarium oxysporum f. sp. melonis were determined in this study. Results from this study showed that the P. aeruginosa strains and their adapted strains significantly inhibited the growth of mycelium ...

[D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P, a potent bombesin antagonist in murine Swiss 3T3 cells, inhibits the growth of human small cell lung cancer cells in vitro.

OpenAIRE

Woll, P J; Rozengurt, E

1988-01-01

In the search for a more potent bombesin antagonist, we found [D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P to be effective in mouse fibroblasts and to inhibit the growth of small cell lung cancer, a tumor that secretes bombesin-like peptides that may act as autocrine growth factors. In murine Swiss 3T3 cells, [D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P proved to be a bombesin antagonist as judged by the following criteria: (i) inhibition of DNA synthesis induced by gastrin-releasing peptide and ot...

Antagonistic Activity of Lactobacillus reuteri Strains on the Adhesion Characteristics of Selected Pathogens.

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Singh, Tejinder P; Kaur, Gurpreet; Kapila, Suman; Malik, Ravinder K

2017-01-01

Adhesion ability of probiotics is the key factor that decides their colonization in the gastrointestinal tract and potential to inhibit pathogens. Therefore, adhesion ability can be considered as a key determinant for probiotic efficacy. Presents study documents the antagonistic activity of viable/untreated, Lithium chloride (LiCl) treated or heat-killed forms of eight probiotic Lactobacillus reuteri strains on the adhesion characteristics of selected pathogens. All strains investigated were able to adhere to Caco-2 cells. L. reuteri strains tested were able to inhibit and displace ( P strain L. reuteri LR6 showed the strongest adhesion and pathogen inhibition ability among the eight L. reuteri strains tested. In addition, the abilities to inhibit and to displace adhered pathogens depended on both the probiotic and the pathogen strains tested suggesting the involvement of various mechanisms. The adhesion and antagonistic potential of the probiotic strains were significantly decreased upon exposure to 5 M LiCl, showing that surface molecules, proteinaceous in nature, are involved. The heat-killed forms of the probiotic L. reuteri strains also inhibited the attachment of selected pathogens to Caco-2 cells. In conclusion, in vitro assays showed that L. reuteri strains, as viable or heat-killed forms, are adherent to Caco-2 cells and are highly antagonistic to pathogens tested in which surface associated proteins play an important role.

Identification of Adenyl Cyclase Activity in a Disease Resistance Protein in Arabidopsis thaliana

KAUST Repository

Hussein, Rana

2012-01-01

center motif. In an attempt to prove that this candidate has adenyl cyclases activity in vitro, the coding sequence of the putative AC catalytic domain of this protein was cloned and expressed in E. coli and the recombinant protein was purified

Preparation and Characterization of an Antibody Antagonist That Targets the Porcine Growth Hormone Receptor

Directory of Open Access Journals (Sweden)

Huanzhong Cui

2016-10-01

Full Text Available A series of antagonists specifically targeting growth hormone receptors (GHR in different species, such as humans, rats, bovines, and mice, have been designed; however, there are currently no antagonists that target the porcine growth hormone (GH. Therefore, in this study, we developed and characterized a porcine GHR (pGHR antibody antagonist (denoted by AN98 via the hybridoma technique. The results from enzyme-linked immunosorbent assay, fluorescence activated cell sorter, indirect immunoinfluscent assay, and competitive receptor binding analysis showed that AN98 could specifically recognize pGHR, and further experiments indicated that AN98 could effectively inhibit pGH-induced signalling in CHO-pGHR cells and porcine hepatocytes. In addition, AN98 also inhibited GH-induced insulin-like growth factor-1 (IGF-1 secretion in porcine hepatocytes. In summary, these findings indicated that AN98, as a pGHR-specific antagonist, has potential applications in pGH-pGHR-related research on domestic pigs.

New antagonists of LHRH. II. Inhibition and potentiation of LHRH by closely related analogues.

Science.gov (United States)

Bajusz, S; Csernus, V J; Janaky, T; Bokser, L; Fekete, M; Schally, A V

1988-12-01

Modifications of the previously described LHRH antagonists, [Ac-D-Nal(2)1, D-Phe(4Cl)2, D-Trp3, D-Cit6, D-Ala10]LHRH and the corresponding D-Hci6 analogue, have been made to alter the hydrophobicity of the N-terminal acetyl-tripeptide portion. Substitution of D-Trp3 with the less hydrophobic D-Pal(3) had only marginal effects on the antagonistic activities and receptor binding potencies of the D-Cit/D-Hci6 analogues, but it appeared to further improve the toxicity lowering effect of D-Cit/D-Hci6 substitution. Antagonists containing D-Pal(3)3 and D-Cit/D-Hci6 residues, i.e. [Ac-D-Nal(2)1, D-Phe(4Cl)2, D-Pal(3)3, D-Cit6, D-Ala10]LHRH (SB-75) and [Ac-D-Nal(2)1, D-Phe(4Cl)2, D-Pal(3)3, D-Hci6, D-Ala10]LHRH (SB-88), were completely free of the toxic effects, such as cyanosis and respiratory depression leading to death, which have been observed in rats with the D-Trp3, D-Arg6 antagonist and related antagonists. Replacement of the N-acetyl group with the hydrophilic carbamoyl group caused a slight decrease in antagonistic activities, particularly in vitro. Introduction of urethane type acyl group such as methoxycarbonyl (Moc) or t-butoxycarbonyl (Boc) led to analogues that showed LHRH-potentiating effect. The increase in potency induced by these analogues, e.g. [Moc-D-Nal(2)1, D-Phe(4Cl)2, D-Trp3, D-Cit6, D-Ala10]LHRH and [Boc-D-Phe1, D-Phe(4Cl)2, D-Pal(3)3, D-Cit6, D-Ala10]LHRH, was 170-260% and persisted for more than 2 h when studied in a superfused rat pituitary system.

Interaction between Ca++-channel antagonists and α2-adrenergic receptors in rabbit ileal cell membrane

International Nuclear Information System (INIS)

Homeidan, F.R.; Wicks, J.; Cusolito, S.; El-Sabban, M.E.; Sharp, G.W.G.; Donowitz, M.

1986-01-01

An interaction between Ca ++ -channel antagonists and the α 2 -adrenergic receptor on active electrolyte transport was demonstrated in rabbit ileum. Clonidine, an α 2 -agonist, stimulated NaCl absorption apparently by Ca ++ -channel antagonism since it inhibited 45 Ca ++ uptake across the basolateral membrane and decreased total ileal calcium content. This stimulation was inhibited by the Ca ++ -channel antagonists dl- and l-verapamil and cadmium but not by nifedipine. The binding of 3 H-yohimbine, a specific α 2 -adrenergic antagonist, was studied on purified ileal cell membranes using a rapid filtration technique. dl-Verapamil and Cd ++ inhibited the specific binding of 3 H-yohimbine over the same concentration range in which they affected transport. In contrast, nifedipine had no effect on binding, just as it had no effect on clonidine-stimulated NaCl absorption. These data demonstrate that there is an interaction between Ca ++ -channels and α 2 -adrenergic receptors in ileal basolateral membranes. Some Ca ++ -channel antagonists alter α 2 -adrenergic binding to the receptor and α 2 -agonist binding leads to changes in Ca ++ entry. A close spatial relationship between the Ca ++ -channel and the α 2 -receptor could explain the data

Effects of sigma(1) receptor ligand MS-377 on D(2) antagonists-induced behaviors.

Science.gov (United States)

Karasawa, Jun-ichi; Takahashi, Shinji; Takagi, Kaori; Horikomi, Kazutoshi

2002-10-01

(R)-(+)-1-(4-Chlorophenyl)-3-[4-(2-methoxyethyl)piperazin-1-yl]methyl-2-pyrrolidinone L-tartrate (MS-377) is a novel antipsychotic agent with selective and high affinity for sigma(1) receptor. The present study was carried out to clarify the interaction of MS-377 with dopamine D(2) receptor antagonists (D(2) antagonists) in concurrent administration, and then the involvement of sigma receptors in the interaction. The effects of MS-377 on haloperidol- or sultopride-induced inhibition of apomorphine-induced climbing behavior and catalepsy were investigated in mice and rats, respectively. In addition, the effects of (+)-SKF-10,047 and SA4503, both of which are sigma receptor agonists, and WAY-100,635, which is a 5-HT(1A) receptor antagonist, on the interaction due to the concurrent use were also investigated. MS-377 potentiated the inhibitory effects of haloperidol or sultopride on apomorphine-induced climbing behavior in a dose-dependent manner. In contrast, MS-377 did not affect the catalepsy induction by these drugs. The potentiation of the inhibitory effects of haloperidol or sultopride on apomorphine-induced climbing behavior by MS-377 was not inhibited by WAY-100,635, but was inhibited by (+)-SKF-10,047 and SA4503. These findings showed that MS-377 potentiates the efficacy of D(2) antagonists, but it does not deteriorate the adverse effect. Moreover, sigma(1) receptors are involved in this potentiation of the efficacy of D(2) antagonists by MS-377.

Pituitary Adenylate-Cyclase Activating Polypeptide Regulates Hunger- and Palatability-Induced Binge Eating

Directory of Open Access Journals (Sweden)

Matthew M. Hurley

2016-08-01

Full Text Available While pituitary adenylate cyclase activating polypeptide (PACAP signaling in the hypothalamic ventromedial nuclei (VMN has been shown to regulate feeding, a challenge in unmasking a role for this peptide in obesity is that excess feeding can involve numerous mechanisms including homeostatic (hunger and hedonic-related (palatability drives. In these studies, we first isolated distinct feeding drives by developing a novel model of binge behavior in which homeostatic-driven feeding was temporally separated from feeding driven by food palatability. We found that stimulation of the VMN, achieved by local microinjections of AMPA, decreased standard chow consumption in food-restricted rats (e.g., homeostatic feeding; surprisingly, this manipulation failed to alter palatable food consumption in satiated rats (e.g., hedonic feeding. In contrast, inhibition of the nucleus accumbens (NAc, through local microinjections of GABA receptor agonists baclofen and muscimol, decreased hedonic feeding without altering homeostatic feeding. PACAP microinjections produced the site-specific changes in synaptic transmission needed to decrease feeding via VMN or NAc circuitry. PACAP into the NAc mimicked the actions of GABA agonists by reducing hedonic feeding without altering homeostatic feeding. In contrast, PACAP into the VMN mimicked the actions of AMPA by decreasing homeostatic feeding without affecting hedonic feeding. Slice electrophysiology recordings verified PACAP excitation of VMN neurons and inhibition of NAc neurons. These data suggest that the VMN and NAc regulate distinct circuits giving rise to unique feeding drives, but that both can be regulated by the neuropeptide PACAP to potentially curb excessive eating stemming from either drive.

Pharmacological differences between the D-2 autoreceptor and the D-1 dopamine receptor in rabbit retina

International Nuclear Information System (INIS)

Dubocovich, M.L.; Weiner, N.

1985-01-01

The effect of dopamine receptor agonists and antagonists was studied on the calcium-dependent release of [ 3 H]dopamine elicited by field stimulation at 3 Hz for a duration of 1 min (20 mA, 2 msec) from the rabbit retina in vitro and on adenylate cyclase activity in homogenates of rabbit retina. The relative order of potency of dopamine receptor agonists to inhibit the stimulation-evoked [ 3 H]dopamine release was pergolide greater than bromocriptine greater than apomorphine greater than LY 141865 greater than N,N-di-n-propyldopamine greater than or equal to dopamine. The relative order of potencies of dopamine receptor antagonists to increase [ 3 H]dopamine release was: S-sulpiride greater than or equal to domperidone greater than or equal to spiroperidol greater than metoclopramide greater than fluphenazine greater than or equal to R-sulpiride. alpha-Flupenthixol (0.01-1 microM) and (+)-butaclamol (0.01-1 microM) did not increase [ 3 H]dopamine overflow when added alone, but they antagonized the concentration-dependent inhibitory effect of apomorphine (0.1-10 microM). These results suggest that the dopamine inhibitory autoreceptor involved in the modulation of dopamine release from the rabbit retina possesses the pharmacological characteristics of a D-2 dopamine receptor. Maximal stimulation by 30 microM dopamine resulted in a 3-fold increase in adenylate cyclase activity with half-maximal stimulation occurring at a concentration of 2.46 microM. Apomorphine and pergolide elicited a partial stimulation of adenylate cyclase activity. However, at low concentrations both compounds were more potent than dopamine

Antiallergic effects of H1-receptor antagonists.

Science.gov (United States)

Baroody, F M; Naclerio, R M

2000-01-01

The primary mechanism of antihistamine action in the treatment of allergic diseases is believed to be competitive antagonism of histamine binding to cellular receptors (specifically, the H1-receptors), which are present on nerve endings, smooth muscles, and glandular cells. This notion is supported by the fact that structurally unrelated drugs antagonize the H1-receptor and provide clinical benefit. However, H1-receptor antagonism may not be their sole mechanism of action in treating allergic rhinitis. On the basis of in vitro and animal experiments, drugs classified as H1-receptor antagonists have long been recognized to have additional pharmacological properties. Most first-generation H1-antihistamines have anticholinergic, sedative, local anaesthetic, and anti-5-HT effects, which might favourably affect the symptoms of the allergic response but also contribute to side-effects. These additional properties are not uniformly distributed among drugs classified as H1-receptor antagonists. Azatadine, for example, inhibits in vitro IgE-mediated histamine and leukotriene (LT) release from mast cells and basophils. In human challenge models, terfenadine, azatadine, and loratadine reduce IgE-mediated histamine release. Cetirizine reduces eosinophilic infiltration at the site of antigen challenge in the skin, but not the nose. In a nasal antigen challenge model, cetirizine pretreatment did not affect the levels of histamine and prostaglandin D2 recovered in postchallenge lavages, whereas the levels of albumin, N-tosyl-L-arginine methyl ester (TAME) esterase activity, and LTs were reduced. Terfenadine, cetirizine, and loratadine blocked allergen-induced hyperresponsiveness to methacholine. In view of the complexity of the pathophysiology of allergy, a number of H1 antagonists with additional properties are currently under development for allergic diseases. Mizolastine, a new H1-receptor antagonist, has been shown to have additional actions that should help reduce the

Anti-HIV Effect of Liposomes Bearing CXCR4 Receptor Antagonist ...

African Journals Online (AJOL)

Keywords: Antagonist, CXCR4, Liposomes, Receptor, Inflammation, HIV. Tropical Journal of ... receptors and inhibits HIV-1 entry mediated through CCR3, CCR5, and ..... circulation, facilitating HIV-targeted drug delivery. By tissue distribution ...

Pre-treatment with Toll-like receptor 4 antagonist inhibits lipopolysaccharide-induced preterm uterine contractility, cytokines, and prostaglandins in rhesus monkeys

Science.gov (United States)

Adams Waldorf, Kristina M.; Persing, David; Novy, Miles J.; Sadowsky, Drew W.; Gravett, Michael G.

2009-01-01

Intra-uterine infection, which occurs in the majority of early preterm births, triggers an immune response culminating in preterm labor. We hypothesized that blockade of lipopolysaccharide (LPS)-induced immune responses by a Toll-like receptor 4 antagonist (TLR4A) would prevent elevations in amniotic fluid (AF) cytokines, prostaglandins, and uterine contractility. Chronically catheterized rhesus monkeys at 128-147 days gestation received intra-amniotic infusions of either: 1) saline (n=6), 2) LPS (0.15-10μg; n=4), or 3) TLR4A pre-treatment with LPS (10 μg) one hour later (n=4). AF cytokines, prostaglandins, and uterine contractility were compared using oneway ANOVA with Bonferroni-adjusted pairwise comparisons. Compared to saline controls, LPS induced significant elevations in AF IL-8, TNF-α, PGE2, PGF2α, and uterine contractility (p<0.05). In contrast, TLR4A pre-treatment inhibited LPS-induced uterine activity and was associated with significantly lower AF IL-8, TNF-α, PGE2, and PGF2α versus LPS alone (p<0.05). Toll-like receptor antagonists, together with antibiotics, may delay or prevent infection-associated preterm birth. PMID:18187405

Structural studies of Schistosoma mansoni adenylate kinases

International Nuclear Information System (INIS)

Marques, I.A.; Pereira, H.M.; Garrat, R.C.

2012-01-01

Full text: Parasitic diseases are a major cause of death in developing countries, however receive little or no attention from pharmaceutical companies for the development of novel therapies. In this respect, the Center for Structural Molecular Biology (CBME) of the Institute of Physics of Sao Carlos (IFSC / USP) has developed expertise in all stages of the development of active compounds against target enzymes from parasitic diseases. The present work focuses on the adenylate kinase enzymes (ADK's) from Schistosoma mansoni. These enzymes are widely distributed and catalyze the reaction of phosphoryl exchange between nucleotides in the reaction 2ADP to ATP + AMP, which is critical for the cells life cycle. Due to the particular property of the reaction catalyzed, the ADK's are recognized as reporters of the cells energetic state, translating small changes in the balance between ATP and ADP into a large change in concentration of AMP. The genome of S. mansoni was recently sequenced by the Sanger Center in England. On performing searches for genes encoding adenylate kinases we found two such genes. The corresponding gene products were named ADK1 (197 residues) and ADK2 (239 residues), and the two sequences share only 28 percent identity. Both have been cloned into the pET-28a(+)vector, expressed in E. coli and purified. Preliminary tests of activity have been performed only for ADK1 showing it to be catalytically active. Crystallization trials were performed for both proteins and thus far, crystals of ADK1 have been obtained which diffract to 2.05 at the LNLS beamline MX2 and the structure solved by molecular replacement. Understanding, at the atomic level, the function of these enzymes may help in the development of specific inhibitors and may provide tools for developing diagnostic tests for schistosomiasis. (author)

A homolog of the vertebrate pituitary adenylate cyclase-activating polypeptide is both necessary and instructive for the rapid formation of associative memory in an invertebrate.

Science.gov (United States)

Pirger, Zsolt; László, Zita; Kemenes, Ildikó; Tóth, Gábor; Reglodi, Dóra; Kemenes, György

2010-10-13

Similar to other invertebrate and vertebrate animals, cAMP-dependent signaling cascades are key components of long-term memory (LTM) formation in the snail Lymnaea stagnalis, an established experimental model for studying evolutionarily conserved molecular mechanisms of long-term associative memory. Although a great deal is already known about the signaling cascades activated by cAMP, the molecules involved in the learning-induced activation of adenylate cyclase (AC) in Lymnaea remained unknown. Using matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy in combination with biochemical and immunohistochemical methods, recently we have obtained evidence for the existence of a Lymnaea homolog of the vertebrate pituitary adenylate cyclase-activating polypeptide (PACAP) and for the AC-activating effect of PACAP in the Lymnaea nervous system. Here we first tested the hypothesis that PACAP plays an important role in the formation of robust LTM after single-trial classical food-reward conditioning. Application of the PACAP receptor antagonist PACAP6-38 around the time of single-trial training with amyl acetate and sucrose blocked associative LTM, suggesting that in this "strong" food-reward conditioning paradigm the activation of AC by PACAP was necessary for LTM to form. We found that in a "weak" multitrial food-reward conditioning paradigm, lip touch paired with sucrose, memory formation was also dependent on PACAP. Significantly, systemic application of PACAP at the beginning of multitrial tactile conditioning accelerated the formation of transcription-dependent memory. Our findings provide the first evidence to show that in the same nervous system PACAP is both necessary and instructive for fast and robust memory formation after reward classical conditioning.

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

2012-01-01

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...

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.

Anti-idiotypic antibody: A new strategy for the development of a growth hormone receptor antagonist.

Science.gov (United States)

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

2015-11-01

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

D-2 dopamine receptor activation reduces free [3H]arachidonate release induced by hypophysiotropic peptides in anterior pituitary cells

International Nuclear Information System (INIS)

Canonico, P.L.

1989-01-01

Dopamine reduces the stimulation of intracellular [ 3 H]arachidonate release produced by the two PRL-stimulating peptides angiotensin-II and TRH. This effect is concentration dependent and is mediated by stimulation of D-2 dopamine receptors. D-2 receptor agonists (bromocriptine, dihydroergocryptine, and dihydroergocristine) inhibit the release of fatty acid induced by angiotensin-II with a potency that parallels their ability to inhibit PRL release in vitro. Conversely, the selective D-2 receptor antagonist L-sulpiride completely prevents dopamine's effect, whereas SCH 23390 (a D-1 receptor antagonist) is ineffective. The inhibitory action of dopamine does not seem to be consequent to an action on the adenylate cyclase-cAMP system, as 8-bromo-cAMP (1 mM) does not affect either basal or dopamine-inhibited [ 3 H]arachidonate release. However, a 24-h pertussis toxin pretreatment significantly reduces the action of dopamine on fatty acid release. Collectively, these results suggest that D-2 dopamine receptor-mediated inhibition of intracellular [ 3 H]arachidonate release requires the action of a GTP-binding protein, but is not a consequence of an inhibitory action on cAMP levels

Accelerated evolution of the pituitary adenylate cyclase-activating polypeptide precursor gene during human origin

DEFF Research Database (Denmark)

Wang, Yin-Qiu; Qian, Ya-Ping; Yang, Su

2005-01-01

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide abundantly expressed in the central nervous system and involved in regulating neurogenesis and neuronal signal transduction. The amino acid sequence of PACAP is extremely conserved across vertebrate species, indicating a...

Mechanism of adenylate kinase: Site-directed mutagenesis versus x-ray and NMR

International Nuclear Information System (INIS)

Tsai, Mingdaw; Yan, Honggao

1991-01-01

Controversy is an integral part of scientific research and is often a precursor to the truth. However, this lesson has been learned in a very hard way in the case of the structure-function relationship of adenylate kinase (AK), which catalyzes the interconversion between MgATP+AMP and MgADP+ADP. While this small kinase has been considered a model kinase and the enzyme-substrate interaction of AK was among the first investigated by X-ray crystallography and NMR the substrate binding sites deduced from the early studies by these two powerful techniques (termed the X-ray model and the NMR model, respectively) were dramatically different. Ironically, both models have had substantial impact on researchers in related fields. The problems have finally been dealt with since 1987 by the interplay between site-directed mutagenesis, X-ray, and NMR. The purpose of this review is not only to summarize the current knowledge in the structure-function relationship of adenylate kinase but also to accurately document and critically analyze historical developments in the hope that history will not be repeated

Adenylate control contributes to thermal acclimation of sugar maple fine-root respiration in experimentally warmed soil.

Science.gov (United States)

Jarvi, Mickey P; Burton, Andrew J

2018-03-01

We investigated the occurrence of and mechanisms responsible for acclimation of fine-root respiration of mature sugar maple (Acer saccharum) after 3+ years of experimental soil warming (+4 to 5 °C) in a factorial combination with soil moisture addition. Potential mechanisms for thermal respiratory acclimation included changes in enzymatic capacity, as indicated by root N concentration; substrate limitation, assessed by examining nonstructural carbohydrates and effects of exogenous sugar additions; and adenylate control, examined as responses of root respiration to a respiratory uncoupling agent. Partial acclimation of fine-root respiration occurred in response to soil warming, causing specific root respiration to increase to a much lesser degree (14% to 26%) than would be expected for a 4 to 5 °C temperature increase (approximately 55%). Acclimation was greatest when ambient soil temperature was warmer or soil moisture availability was low. We found no evidence that enzyme or substrate limitation caused acclimation but did find evidence supporting adenylate control. The uncoupling agent caused a 1.4 times greater stimulation of respiration in roots from warmed soil. Sugar maple fine-root respiration in warmed soil was at least partially constrained by adenylate use, helping constrain respiration to that needed to support work being performed by the roots. © 2017 John Wiley & Sons Ltd.

Pituitary adenylate cyclase-activating polypeptide stimulates renin secretion via activation of PAC1 receptors

DEFF Research Database (Denmark)

Hautmann, Matthias; Friis, Ulla G; Desch, Michael

2007-01-01

Besides of its functional role in the nervous system, the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) is involved in the regulation of cardiovascular function. Therefore, PACAP is a potent vasodilator in several vascular beds, including the renal vasculature. Because...

A comprehensive survey of 3′ animal miRNA modification events and a possible role for 3′ adenylation in modulating miRNA targeting effectiveness

Science.gov (United States)

Burroughs, A. Maxwell; Ando, Yoshinari; de Hoon, Michiel J.L.; Tomaru, Yasuhiro; Nishibu, Takahiro; Ukekawa, Ryo; Funakoshi, Taku; Kurokawa, Tsutomu; Suzuki, Harukazu; Hayashizaki, Yoshihide; Daub, Carsten O.

2010-01-01

Animal microRNA sequences are subject to 3′ nucleotide addition. Through detailed analysis of deep-sequenced short RNA data sets, we show adenylation and uridylation of miRNA is globally present and conserved across Drosophila and vertebrates. To better understand 3′ adenylation function, we deep-sequenced RNA after knockdown of nucleotidyltransferase enzymes. The PAPD4 nucleotidyltransferase adenylates a wide range of miRNA loci, but adenylation does not appear to affect miRNA stability on a genome-wide scale. Adenine addition appears to reduce effectiveness of miRNA targeting of mRNA transcripts while deep-sequencing of RNA bound to immunoprecipitated Argonaute (AGO) subfamily proteins EIF2C1–EIF2C3 revealed substantial reduction of adenine addition in miRNA associated with EIF2C2 and EIF2C3. Our findings show 3′ addition events are widespread and conserved across animals, PAPD4 is a primary miRNA adenylating enzyme, and suggest a role for 3′ adenine addition in modulating miRNA effectiveness, possibly through interfering with incorporation into the RNA-induced silencing complex (RISC), a regulatory role that would complement the role of miRNA uridylation in blocking DICER1 uptake. PMID:20719920

Quantification of potassium levels in cells treated with Bordetella adenylate cyclase toxin

Czech Academy of Sciences Publication Activity Database

Wald, Tomáš; Petry-Podgorska, Inga; Fišer, Radovan; Matoušek, Tomáš; Dědina, Jiří; Osička, Radim; Šebo, Peter; Mašín, Jiří

2014-01-01

Roč. 450, APR 2014 (2014), s. 57-62 ISSN 0003-2697 R&D Projects: GA ČR(CZ) GAP302/11/0580; GA ČR GA13-14547S; GA ČR GAP302/12/0460 Institutional support: RVO:61388971 ; RVO:68081715 Keywords : Potassium * Adenylate cyclase toxin * RTX Subject RIV: CE - Biochemistry Impact factor: 2.219, year: 2014

An anti-CCR5 monoclonal antibody and small molecule CCR5 antagonists synergize by inhibiting different stages of human immunodeficiency virus type 1 entry

International Nuclear Information System (INIS)

Safarian, Diana; Carnec, Xavier; Tsamis, Fotini; Kajumo, Francis; Dragic, Tatjana

2006-01-01

HIV-1 coreceptors are attractive targets for novel antivirals. Here, inhibition of entry by two classes of CCR5 antagonists was investigated. We confirmed previous findings that HIV-1 isolates vary greatly in their sensitivity to small molecule inhibitors of CCR5-mediated entry, SCH-C and TAK-779. In contrast, an anti-CCR5 monoclonal antibody (PA14) similarly inhibited entry of diverse viral isolates. Sensitivity to small molecules was V3 loop-dependent and inversely proportional to the level of gp120 binding to CCR5. Moreover, combinations of the MAb and small molecules were highly synergistic in blocking HIV-1 entry, suggesting different mechanisms of action. This was confirmed by time course of inhibition experiments wherein the PA14 MAb and small molecules were shown to inhibit temporally distinct stages of CCR5 usage. We propose that small molecules inhibit V3 binding to the second extracellular loop of CCR5, whereas PA14 preferentially inhibits subsequent events such as CCR5 recruitment into the fusion complex or conformational changes in the gp120-CCR5 complex that trigger fusion. Importantly, our findings suggest that combinations of CCR5 inhibitors with different mechanisms of action will be central to controlling HIV-1 infection and slowing the emergence of resistant strains

Third Acivity of Bordetella Adenylate Cyclase (AC) Toxin-Hemolysin

Czech Academy of Sciences Publication Activity Database

Fišer, Radovan; Mašín, Jiří; Basler, Marek; Krůšek, Jan; Špuláková, V.; Konopásek, Ivo; Šebo, Peter

2007-01-01

Roč. 282, č. 5 (2007), s. 2808-2820 ISSN 0021-9258 R&D Projects: GA MŠk 1M0506; GA AV ČR IAA5020406 Grant - others:XE(XE) LSHB-CT-2003-503582; Univerzita Karlova(CZ) 146/2005/B-BIO Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z50110509 Source of funding: R - rámcový projekt EK ; V - iné verejné zdroje Keywords : bordetella * adenylate cyclase toxin * enzymatic aktivity Subject RIV: EE - Microbiology, Virology Impact factor: 5.581, year: 2007

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

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Qing Li

2016-06-01

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.

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

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Carina J. Bleickardt

2012-01-01

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.

Initiation of proteolysis of yeast fructose-1,6-bisphosphatase by pH-control of adenylate cyclase

International Nuclear Information System (INIS)

Holzer, H.; Purwin, C.; Pohlig, G.; Scheffers, W.A.; Nicolay, K.

1986-01-01

Addition of fermentable sugars or uncouplers such as CCCP to resting yeast cells grown on glucose initiates phosphorylation of fructose-1,6-bisphosphatase (FBPase). There is good evidence that phosphorylation marks FBPase for proteolytic degradation. 31 P-NMR measurements of the cytosolic pH of yeast cells demonstrated a decrease of the cytosolic pH from 7.0 to 6.5 after addition of glucose or CCCP to starved yeast. Activity of adenylate cyclase in permeabilized yeast cells increases 2-3-fold when the pH is lowered from 7.0 to 6.5. It is concluded that pH controlled activation of adenylate cyclase causes the previously described increase in cyclic AMP which leads to phosphorylation of FBPase and finally to proteolysis of FBPase

Recent progress in the development of small-molecule glucagon receptor antagonists.

Science.gov (United States)

Sammons, Matthew F; Lee, Esther C Y

2015-10-01

The endocrine hormone glucagon stimulates hepatic glucose output via its action at the glucagon receptor (GCGr) in the liver. In the diabetic state, dysregulation of glucagon secretion contributes to abnormally elevated hepatic glucose output. The inhibition of glucagon-induced hepatic glucose output via antagonism of the GCGr using small-molecule ligands is a promising mechanism for improving glycemic control in the diabetic state. Clinical data evaluating the therapeutic potential of small-molecule GCGr antagonists is currently emerging. Recently disclosed clinical data demonstrates the potential efficacy and possible therapeutic limitations of small-molecule GCGr antagonists. Recent pre-clinical work on the development of GCGr antagonists is also summarized. Copyright © 2015 Elsevier Ltd. All rights reserved.

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: wangmw@mail.shcnc.ac.cn [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)

2010-01-15

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.

Characterization of a novel non-steroidal glucocorticoid receptor antagonist

International Nuclear Information System (INIS)

Li, Qun-Yi; Zhang, Meng; Hallis, Tina M.; DeRosier, Therese A.; Yue, Jian-Min; Ye, Yang; Mais, Dale E.; Wang, Ming-Wei

2010-01-01

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 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.

Angiotensin II potentiates prostaglandin stimulation of cyclic AMP levels in intact bovine adrenal medulla cells but not adenylate cyclase in permeabilized cells.

Science.gov (United States)

Boarder, M R; Plevin, R; Marriott, D B

1988-10-25

The level of cyclic AMP in primary cultures of bovine adrenal medulla cells is elevated by prostaglandin E1. Angiotensin II is commonly reported to act on receptors linked to phosphoinositide metabolism or to inhibition of adenylate cyclase. We have investigated the effect of angiotensin II on prostaglandin E1-stimulated cyclic AMP levels in these primary cultures. Rather than reducing cyclic AMP levels, we have found that angiotensin II powerfully potentiates prostaglandin E1-stimulated cyclic AMP accumulation in intact cells, both in the presence and absence of phosphodiesterase inhibitors. The 50% maximal response was similar to that for stimulation of phosphoinositide breakdown by angiotensin II in these cultures. The potentiation of stimulated cyclic AMP levels was seen, although to a smaller maximum, with the protein kinase C (Ca2+/phospholipid-dependent enzyme) activating phorbol ester tetradecanoyl phorbolacetate and with the synthetic diacylglycerol 1-oleoyl-2-acetylglycerol; pretreatment (24 h) with active phorbol ester, which would be expected to diminish protein kinase C levels, attenuated the angiotensin II potentiation of cyclic AMP. Using digitonin-permeabilized cells we showed that adenylate cyclase activity was stimulated by prostaglandin E1 with the same dose-response relationship as was cyclic AMP accumulation in intact cells, but the permeabilized cells showed no response to angiotensin II. The results are discussed with respect to the hypothesis that the angiotensin II influence on cyclic AMP levels is mediated, in part, by diacylglycerol stimulation of protein kinase C.

Adenylate cyclase toxin promotes internalisation of integrins and raft components and decreases macrophage adhesion capacity.

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César Martín

Full Text Available Bordetella pertussis, the bacterium that causes whooping cough, secretes an adenylate cyclase toxin (ACT that must be post-translationally palmitoylated in the bacterium cytosol to be active. The toxin targets phagocytes expressing the CD11b/CD18 integrin receptor. It delivers a catalytic adenylate cyclase domain into the target cell cytosol producing a rapid increase of intracellular cAMP concentration that suppresses bactericidal functions of the phagocyte. ACT also induces calcium fluxes into target cells. Biochemical, biophysical and cell biology approaches have been applied here to show evidence that ACT and integrin molecules, along with other raft components, are rapidly internalized by the macrophages in a toxin-induced calcium rise-dependent process. The toxin-triggered internalisation events occur through two different routes of entry, chlorpromazine-sensitive receptor-mediated endocytosis and clathrin-independent internalisation, maybe acting in parallel. ACT locates into raft-like domains, and is internalised, also in cells devoid of receptor. Altogether our results suggest that adenylate cyclase toxin, and maybe other homologous pathogenic toxins from the RTX (Repeats in Toxin family to which ACT belongs, may be endowed with an intrinsic capacity to, directly and efficiently, insert into raft-like domains, promoting there its multiple activities. One direct consequence of the integrin removal from the cell surface of the macrophages is the hampering of their adhesion ability, a fundamental property in the immune response of the leukocytes that could be instrumental in the pathogenesis of Bordetella pertussis.

Adenylate cyclase toxin promotes internalisation of integrins and raft components and decreases macrophage adhesion capacity.

Science.gov (United States)

Martín, César; Uribe, Kepa B; Gómez-Bilbao, Geraxane; Ostolaza, Helena

2011-02-23

Bordetella pertussis, the bacterium that causes whooping cough, secretes an adenylate cyclase toxin (ACT) that must be post-translationally palmitoylated in the bacterium cytosol to be active. The toxin targets phagocytes expressing the CD11b/CD18 integrin receptor. It delivers a catalytic adenylate cyclase domain into the target cell cytosol producing a rapid increase of intracellular cAMP concentration that suppresses bactericidal functions of the phagocyte. ACT also induces calcium fluxes into target cells. Biochemical, biophysical and cell biology approaches have been applied here to show evidence that ACT and integrin molecules, along with other raft components, are rapidly internalized by the macrophages in a toxin-induced calcium rise-dependent process. The toxin-triggered internalisation events occur through two different routes of entry, chlorpromazine-sensitive receptor-mediated endocytosis and clathrin-independent internalisation, maybe acting in parallel. ACT locates into raft-like domains, and is internalised, also in cells devoid of receptor. Altogether our results suggest that adenylate cyclase toxin, and maybe other homologous pathogenic toxins from the RTX (Repeats in Toxin) family to which ACT belongs, may be endowed with an intrinsic capacity to, directly and efficiently, insert into raft-like domains, promoting there its multiple activities. One direct consequence of the integrin removal from the cell surface of the macrophages is the hampering of their adhesion ability, a fundamental property in the immune response of the leukocytes that could be instrumental in the pathogenesis of Bordetella pertussis.

Development of specific dopamine D-1 agonists and antagonists

International Nuclear Information System (INIS)

Sakolchai, S.

1987-01-01

To develop potentially selective dopamine D-1 agonists and to investigate on the structural requirement for D-1 activity, the derivatives of dibenzocycloheptadiene are synthesized and pharmacologically evaluated. The target compounds are 5-aminomethyl-10,11-dihydro-1,2-dihydroxy-5H-dibenzo[a,d]cycloheptene hydrobromide 10 and 9,10-dihydroxy-1,2,3,7,8,12b-hexahydrobenzo[1,2]cyclohepta[3,4,5d,e]isoquinoline hydrobromide 11. In a dopamine-sensitive rat retinal adenylate cyclase assay, a model for D-1 activity, compound 10 is essentially inert for both agonist and antagonist activity. In contrast, compound 11 is approximately equipotent to dopamine in activation of the D-1 receptor. Based on radioligand and binding data, IC 50 of compound 11 for displacement of 3 H-SCH 23390, a D-1 ligand, is about 7 fold less than that for displacement of 3 H-spiperone, a D-2 ligand. These data indicate that compound 11 is a potent selective dopamine D-1 agonist. This study provides a new structural class of dopamine D-1 acting agent: dihydroxy-benzocycloheptadiene analog which can serve as a lead compound for further drug development and as a probe for investigation on the nature of dopamine D-1 receptor

Characterization of a novel serotonin receptor coupled to adenylate cyclase in the hybrid neuroblastoma cell line NCB. 20

Energy Technology Data Exchange (ETDEWEB)

Conner, D.A.

1988-01-01

Pharmacological characterization of the serotonin activation of adenylate cyclase in membrane preparation using over 40 serotonergic and non-serotonergic compounds demonstrated that the receptor mediating the response was distinct from previously described mammalian serotonin receptors. Agonist activity was only observed with tryptamine and ergoline derivatives. Potent antagonism was observed with several ergoline derivatives and with compounds such as mianserin and methiothepine. A comparison of the rank order of potency of a variety of compounds for the NCB.20 cell receptor with well characterized mammalian and non-mammalian serotonin receptors showed a pharmacological similarity, but not identity, with the mammalian 5-HT{sub 1C} receptor, which modulates phosphatidylinositol metabolism, and with serotonin receptors in the parasitic trematodes Fasciola hepatica and Schistosoma mansoni, which are coupled to adenylate cyclase. Equilibrium binding analysis utilizing ({sup 3}H)serotonin, ({sup 3}H)lysergic acid diethylamide or ({sup 3}H)dihydroergotamine demonstrated that there are no abundant high affinity serotonergic sites, which implies that the serotonin activation of adenylate cyclase is mediated by receptors present in low abundance. Incubation of intact NCB.20 cells with serotinin resulted in a time and concentration dependent desensitization of the serotonin receptor.

Characterization of a novel serotonin receptor coupled to adenylate cyclase in the hybrid neuroblastoma cell line NCB.20

International Nuclear Information System (INIS)

Conner, D.A.

1988-01-01

Pharmacological characterization of the serotonin activation of adenylate cyclase in membrane preparation using over 40 serotonergic and non-serotonergic compounds demonstrated that the receptor mediating the response was distinct from previously described mammalian serotonin receptors. Agonist activity was only observed with tryptamine and ergoline derivatives. Potent antagonism was observed with several ergoline derivatives and with compounds such as mianserin and methiothepine. A comparison of the rank order of potency of a variety of compounds for the NCB.20 cell receptor with well characterized mammalian and non-mammalian serotonin receptors showed a pharmacological similarity, but not identity, with the mammalian 5-HT 1C receptor, which modulates phosphatidylinositol metabolism, and with serotonin receptors in the parasitic trematodes Fasciola hepatica and Schistosoma mansoni, which are coupled to adenylate cyclase. Equilibrium binding analysis utilizing [ 3 H]serotonin, [ 3 H]lysergic acid diethylamide or [ 3 H]dihydroergotamine demonstrated that there are no abundant high affinity serotonergic sites, which implies that the serotonin activation of adenylate cyclase is mediated by receptors present in low abundance. Incubation of intact NCB.20 cells with serotinin resulted in a time and concentration dependent desensitization of the serotonin receptor

Adenylate cyclase activity in fish gills in relation to salt adaptation

International Nuclear Information System (INIS)

Guibbolini, M.E.; Lahlou, B.

1987-01-01

The influence of salt adaptation on specific adenylate cyclase activity (measured by conversion of [α- 32 P] - ATP into [α- 32 P] - cAMP) was investigated in gill plasma membranes of rainbow trout (Salmo gairdneri) adapted to various salinities (deionized water, DW; fresh water, FW; 3/4 sea water, 3/4 SW; sea water, SW) and in sea water adapted- mullet (Mugil sp.). Basal activity declined by a factor of 2 in trout with increasing external salinity (pmoles cAMP/mg protein/10 min: 530 in DW, 440 in FW, 340 in 3/4 SW; 250 in SW) and was very low in SW adapted-mullet: 35. The Km for ATP was similar (0.5 mM) in both FW adapted- and SW adapted- trout in either the absence (basal activity) or in the presence of stimulating agents (isoproterenol; NaF) while the Vm varied. Analysis of stimulation ratios with respect to basal levels of the enzyme showed that hormones and pharmacological substances (isoproterenol, NaF) display a greater potency in high salt than in low salt adapted- fish gills. In contrast, salt adaptation did not have any effect on the regulation of adenylate cyclase by PGE 1 . These results are interpreted in relation to the general process of osmoregulation. 27 references, 6 figures

Effects of matrix metalloproteinase inhibitor doxycycline and CD147 antagonist peptide-9 on gallbladder carcinoma cell lines.

Science.gov (United States)

Wang, Shihang; Liu, Chao; Liu, Xinjiang; He, Yanxin; Shen, Dongfang; Luo, Qiankun; Dong, Yuxi; Dong, Haifeng; Pang, Zhigang

2017-10-01

Gallbladder carcinoma is the most common and aggressive malignancy of the biliary tree and highly expresses CD147, which is closely related to disease prognosis in a variety of human cancers. Doxycycline exhibited anti-tumor properties in many cancer cells. CD147 antagonist peptide-9 is a polypeptide and can specifically bind to CD147. The effect of these two drugs on gallbladder cancer cells has not been studied. The aim of this study is to investigate the effect of doxycycline and antagonist peptide-9 on gallbladder carcinoma cells and the possible mechanism of inhibition on cancer cell of doxycycline. To investigate the effects of doxycycline and antagonist peptide-9 on gallbladder carcinoma cells (GBC-SD and SGC-996), cell proliferation, CD147 expression, and early-stage apoptosis rate were measured after treated with doxycycline. Matrix metalloproteinase-2 and matrix metalloproteinase-9 activities were measured after treated with different concentrations of doxycycline, antagonist peptide-9, and their combination. The results demonstrated that doxycycline inhibited cell proliferation, reduced CD147 expression level, and induced an early-stage apoptosis response in GBC-SD and SGC-996 cells. The matrix metalloproteinase-2 and matrix metalloproteinase-9 activities were inhibited by antagonist peptide-9 and doxycycline, and the inhibitory effects were enhanced by combined drugs in gallbladder carcinoma cell lines. Taken together, doxycycline showed inhibitory effects on gallbladder carcinoma cell lines and reduced the expression of CD147, and this may be the mechanism by which doxycycline inhibits cancer cells. This study provides new information and tries to implement the design of adjuvant therapy method for gallbladder carcinoma.

The role of transcriptional regulation in maintaining the availability of mycobacterial adenylate cyclases

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Sarah J. Casey

2014-03-01

Full Text Available Mycobacterium species have a complex cAMP regulatory network indicated by the high number of adenylate cyclases annotated in their genomes. However the need for a high level of redundancy in adenylate cyclase genes remains unknown. We have used semiquantitiative RT-PCR to examine the expression of eight Mycobacterium smegmatis cyclases with orthologs in the human pathogen Mycobacterium tuberculosis, where cAMP has recently been shown to be important for virulence. All eight cyclases were transcribed in all environments tested, and only four demonstrated environmental-mediated changes in transcription. M. smegmatis genes MSMEG_0545 and MSMEG_4279 were upregulated during starvation conditions while MSMEG_0545 and MSMEG_4924 were downregulated in H2O2 and MSMEG_3780 was downregulated in low pH and starvation. Promoter fusion constructs containing M. tuberculosis H37Rv promoters showed consistent regulation compared to their M. smegmatis orthologs. Overall our findings indicate that while low levels of transcriptional regulation occur, regulation at the mRNA level does not play a major role in controlling cellular cyclase availability in a given environment.

Liaison of 3H 5-HT and adenyl cyclasic activation induced by the 5-HT in preparations of brain glial membranes

International Nuclear Information System (INIS)

Fillion, Gilles; Beaudoin, Dominique; Rousselle, J.-C.; Jacob, Joseph

1980-01-01

Purified glial membrane preparations have been isolated from horse brain striatum. Tritiated 5-HT bound to these membranes with a high affinity (K(D)=10 nM); the corresponding bindings is reversible and appears specific of the serotoninergic structure. In parallel, 5-HT activates an adenylate cyclase with a low affinity (K(D)=1 μM). The sites involved in this binding and in this adenylate cyclase activation appear different from the serotoninergic sites reported in the neuronal membrane preparations [fr

A substance P antagonist, [D-Pro2, D-Trp7,9]SP, inhibits inflammatory responses in the rabbit eye

International Nuclear Information System (INIS)

Holmdahl, G.; Hakanson, R.; Leander, S.; Rosell, S.; Folkers, K.; Sundler, F.

1981-01-01

Neurogenic factors released by antidromic nerve stimulation are thought to be in part responsible for the vasodilation and breakdown of the blood-aqueous barrier that follows trauma to the eye. Substance P is one candidate for the mediation of the inflammatory response since it is thought to be a neurotransmitter in sensory afferents and since exogenous substance P is capable of eliciting a response characteristic of inflammation. In rabbits, intravitreal or topical application onto the eye of a specific substance P antagonist, [d-Pro2, D-Trp7,9]SP, inhibited not only the irritant effects of exogenous substance P but also the inflammatory response to a standardized trauma (infrared irradiation of the iris). These observations suggest that substance P, or a related peptide, is a neurogenic mediator of the inflammatory response in the eye

The effects of isatin (indole-2, 3-dione on pituitary adenylate cyclase-activating polypeptide-induced hyperthermia in rats

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Tóth Gábor

2002-02-01

Full Text Available Abstract Background Previous studies have demonstrated that centrally administered natriuretic peptides and pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38 have hyperthermic properties. Isatin (indole-2, 3-dione is an endogenous indole that has previously been found to inhibit hyperthermic effects of natriuretic peptides. In this study the aim was to investigate the effects of isatin on thermoregulatory actions of PACAP-38, in rats. Results One μg intracerebroventricular (icv. injection of PACAP-38 had hyperthermic effect in male, Wistar rats, with an onset of the effect at 2 h and a decline by the 6th h after administration. Intraperitoneal (ip. injection of different doses of isatin (25-50 mg/kg significantly decreased the hyperthermic effect of 1 μg PACAP-38 (icv., whereas 12.5 mg/kg isatin (ip. had no inhibiting effect. Isatin alone did not modify the body temperature of the animals. Conclusion The mechanisms that participate in the mediation of the PACAP-38-induced hyperthermia may be modified by isatin. The capability of isatin to antagonize the hyperthermia induced by all members of the natriuretic peptide family and by PACAP-38 makes it unlikely to be acting directly on receptors for natriuretic peptides or on those for PACAP in these hyperthermic processes.

Effect of inhibition of microsomal Ca(2+)-ATPase on cytoplasmic calcium and enzyme secretion in pancreatic acini.

Science.gov (United States)

Metz, D C; Pradhan, T K; Mrozinski, J E; Jensen, R T; Turner, R J; Patto, R J; Gardner, J D

1994-01-13

We used thapsigargin (TG), 2,5-di-tert-butyl-1,4-benzohydroquinone (BHQ) and cyclopiazonic acid (CPA), each of which inhibits microsomal Ca(2+)-ATPase, to evaluate the effects of this inhibition on cytoplasmic free calcium ([Ca2+]i) and secretagogue-stimulated enzyme secretion in rat pancreatic acini. Using single-cell microspectrofluorimetry of fura-2-loaded acini we found that all three agents caused a sustained increase in [Ca2+]i by mobilizing calcium from inositol-(1,4,5)-trisphosphate-sensitive intracellular calcium stores and by promoting influx of extracellular calcium. Concentrations of all three agents that increased [Ca2+]i potentiated the stimulation of enzyme secretion caused by secretagogues that activate adenylate cyclase but inhibited the stimulation of enzyme secretion caused by secretagogues that activate phospholipase C. With BHQ, potentiation of adenylate cyclase-mediated enzyme secretion occurred immediately whereas inhibition of phospholipase C-mediated enzyme secretion occurred only after several min of incubation. In addition, the effects of BHQ and CPA on both [Ca2+]i and secretagogue-stimulated enzyme secretion were reversed completely by washing whereas the actions of TG could not be reversed by washing. Concentrations of BHQ in excess of those that caused maximal changes in [Ca2+]i inhibited all modes of stimulated enzyme secretion by a mechanism that was apparently unrelated to changes in [Ca2+]i. Finally, in contrast to the findings with TG and BHQ, CPA inhibited bombesin-stimulated enzyme secretion over a range of concentrations that was at least 10-fold lower than the range of concentrations over which CPA potentiated VIP-stimulated enzyme secretion.

Adenylate kinase I does not affect cellular growth characteristics under normal and metabolic stress conditions.

NARCIS (Netherlands)

Bruin, W.C.C. de; Oerlemans, F.T.J.J.; Wieringa, B.

2004-01-01

Adenylate kinase (AK)-catalyzed phosphotransfer is essential in the maintenance of cellular energetic economy in cells of fully differentiated tissues with highly variable energy demand, such as muscle and brain. To investigate if AK isoenzymes have a comparable function in the energy-demand

Benzodiazepine receptor antagonists for acute and chronic hepatic encephalopathy

DEFF Research Database (Denmark)

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

2001-01-01

The pathogenesis of hepatic encephalopathy is unknown. It has been suggested that liver failure leads to the accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition which may progress to coma. Several trials have assessed benzodiazepine receptor...... antagonists for hepatic encephalopathy, but the results are conflicting....

Amine-free melanin-concentrating hormone receptor 1 antagonists: Novel 1-(1H-benzimidazol-6-yl)pyridin-2(1H)-one derivatives and design to avoid CYP3A4 time-dependent inhibition.

Science.gov (United States)

Igawa, Hideyuki; Takahashi, Masashi; Shirasaki, Mikio; Kakegawa, Keiko; Kina, Asato; Ikoma, Minoru; Aida, Jumpei; Yasuma, Tsuneo; Okuda, Shoki; Kawata, Yayoi; Noguchi, Toshihiro; Yamamoto, Syunsuke; Fujioka, Yasushi; Kundu, Mrinalkanti; Khamrai, Uttam; Nakayama, Masaharu; Nagisa, Yasutaka; Kasai, Shizuo; Maekawa, Tsuyoshi

2016-06-01

Melanin-concentrating hormone (MCH) is an attractive target for antiobesity agents, and numerous drug discovery programs are dedicated to finding small-molecule MCH receptor 1 (MCHR1) antagonists. We recently reported novel pyridine-2(1H)-ones as aliphatic amine-free MCHR1 antagonists that structurally featured an imidazo[1,2-a]pyridine-based bicyclic motif. To investigate imidazopyridine variants with lower basicity and less potential to inhibit cytochrome P450 3A4 (CYP3A4), we designed pyridine-2(1H)-ones bearing various less basic bicyclic motifs. Among these, a lead compound 6a bearing a 1H-benzimidazole motif showed comparable binding affinity to MCHR1 to the corresponding imidazopyridine derivative 1. Optimization of 6a afforded a series of potent thiophene derivatives (6q-u); however, most of these were found to cause time-dependent inhibition (TDI) of CYP3A4. As bioactivation of thiophenes to form sulfoxide or epoxide species was considered to be a major cause of CYP3A4 TDI, we introduced electron withdrawing groups on the thiophene and found that a CF3 group on the ring or a Cl adjacent to the sulfur atom helped prevent CYP3A4 TDI. Consequently, 4-[(5-chlorothiophen-2-yl)methoxy]-1-(2-cyclopropyl-1-methyl-1H-benzimidazol-6-yl)pyridin-2(1H)-one (6s) was identified as a potent MCHR1 antagonist without the risk of CYP3A4 TDI, which exhibited a promising safety profile including low CYP3A4 inhibition and exerted significant antiobesity effects in diet-induced obese F344 rats. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigation of the pathophysiological mechanisms of migraine attacks induced by pituitary adenylate cyclase-activating polypeptide-38

DEFF Research Database (Denmark)

Amin, Faisal Mohammad; Hougaard, Anders; Schytz, Henrik W

2014-01-01

Pituitary adenylate cyclase-activating polypeptide-38 (PACAP38) and vasoactive intestinal polypeptide are structurally and functionally closely related but show differences in migraine-inducing properties. Mechanisms responsible for the difference in migraine induction are unknown. Here, for the ...

Tye7 regulates yeast Ty1 retrotransposon sense and antisense transcription in response to adenylic nucleotides stress.

Science.gov (United States)

Servant, Géraldine; Pinson, Benoit; Tchalikian-Cosson, Aurélie; Coulpier, Fanny; Lemoine, Sophie; Pennetier, Carole; Bridier-Nahmias, Antoine; Todeschini, Anne Laure; Fayol, Hélène; Daignan-Fornier, Bertrand; Lesage, Pascale

2012-07-01

Transposable elements play a fundamental role in genome evolution. It is proposed that their mobility, activated under stress, induces mutations that could confer advantages to the host organism. Transcription of the Ty1 LTR-retrotransposon of Saccharomyces cerevisiae is activated in response to a severe deficiency in adenylic nucleotides. Here, we show that Ty2 and Ty3 are also stimulated under these stress conditions, revealing the simultaneous activation of three active Ty retrotransposon families. We demonstrate that Ty1 activation in response to adenylic nucleotide depletion requires the DNA-binding transcription factor Tye7. Ty1 is transcribed in both sense and antisense directions. We identify three Tye7 potential binding sites in the region of Ty1 DNA sequence where antisense transcription starts. We show that Tye7 binds to Ty1 DNA and regulates Ty1 antisense transcription. Altogether, our data suggest that, in response to adenylic nucleotide reduction, TYE7 is induced and activates Ty1 mRNA transcription, possibly by controlling Ty1 antisense transcription. We also provide the first evidence that Ty1 antisense transcription can be regulated by environmental stress conditions, pointing to a new level of control of Ty1 activity by stress, as Ty1 antisense RNAs play an important role in regulating Ty1 mobility at both the transcriptional and post-transcriptional stages.

Reversible switching of fluorophore property based on intrinsic conformational transition of adenylate kinase during its catalytic cycle.

Science.gov (United States)

Fujii, Akira; Hirota, Shun; Matsuo, Takashi

2013-07-17

Adenylate kinase shows a conformational transition (OPEN and CLOSED forms) during substrate binding and product release to mediate the phosphoryl transfer between ADP and ATP/AMP. The protein motional characteristics will be useful to construct switching systems of fluorophore properties caused by the catalytic cycle of the enzyme. This paper demonstrates in situ reversible switching of a fluorophore property driven by the conformational transition of the enzyme. The pyrene-conjugated mutant adenylate kinase is able to switch the monomer/excimer emission property of pyrene on addition of ADP or P(1)P(5)-di(adenosine-5')pentaphosphate (Ap5A, a transition state analog). The observation under the dilute condition (~0.1 μM) indicates that the emission spectral change was caused by the motion of a protein molecule and not led by protein-protein interactions through π-π stacking of pyrene rings. The switching can be reversibly conducted by using hexokinase-coupling reaction. The fashion of the changes in emission intensities at various ligand concentrations is different between ADP, Mg(2+)-bound ADP, and Mg(2+)-bound Ap5A. The emission property switching is repeatable by a sequential addition of a substrate in a one-pot process. It is proposed that the property of a synthetic molecule on the enzyme surface is switchable in response to the catalytic cycle of adenylate kinase.

Secreted Wnt antagonists in leukemia: A road yet to be paved.

Science.gov (United States)

Pehlivan, Melek; Çalışkan, Ceyda; Yüce, Zeynep; Sercan, Hakki Ogun

2018-03-28

Wnt signaling has been a topic of research for many years for its diverse and fundamental functions in physiological (such as embryogenesis, organogenesis, proliferation, tissue repair and cellular differentiation) and pathological (carcinogenesis, congenital/genetic diseases, and tissue degeneration) processes. Wnt signaling pathway aberrations are associated with both solid tumors and hematological malignancies. Unregulated Wnt signaling observed in malignancies may be due to a wide spectrum of abnormalities, from mutations in the genes of key players to epigenetic modifications of Wnt antagonists. Of these, Wnt antagonists are gaining significant attention for their potential of being targets for treatment and inhibition of Wnt signaling. In this review, we discuss and summarize the significance of Wnt signaling antagonists in the pathogenesis and treatment of hematological malignancies. Copyright © 2018 Elsevier Ltd. All rights reserved.

The growth hormone-releasing hormone (GHRH) antagonist JV-1-36 inhibits proliferation and survival of human ectopic endometriotic stromal cells (ESCs) and the T HESC cell line.

Science.gov (United States)

Annunziata, Marta; Grande, Cristina; Scarlatti, Francesca; Deltetto, Francesco; Delpiano, Elena; Camanni, Marco; Ghigo, Ezio; Granata, Riccarda

2010-08-01

To determine the effect of the GHRH antagonist JV-1-36 on proliferation and survival of primary ectopic human endometriotic stromal cells (ESCs) and the T HESC cell line. Prospective laboratory study. University hospital. 22 women with endometriosis (aged 34.8+/-5.7 years) undergoing therapeutic laparoscopy. Eutopic (n=10) and ectopic (n=22) endometrial tissues were collected from women who underwent therapeutic laparoscopic surgery for endometriosis (stage III/IV). Expression of GHRH, GHRH receptor (GHRH-R) and GHRH-R splice variant (SV) 1 mRNA was determined by reverse-transcription polymerase chain reaction (RT-PCR). The ESC proliferation was assessed by 5-bromo-2-deoxyuridine incorporation, cell survival by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and Trypan blue assay. The T HESC survival was evaluated by MTT, cyclic adenosine monophosphate (cAMP) levels by ELISA, extracellular signal-regulated kinases 1 and 2 (ERK1/2) phosphorylation by Western blot, and insulin-like growth factor (IGF)-2 mRNA by real-time PCR. The ESCs and T HESCs, but not normal endometrial tissues, expressed GHRH-R mRNA; SV1 mRNA was determined in normal endometrial tissues, ESCs, and T HESCs; GHRH mRNAwas found in T HESCs; JV-1-36 inhibited ESC proliferation and ESC and T HESC survival. In T HESCs, JV-1-36 reduced cAMP production and ERK1/2 phosphorylation but had no effect on IGF-2 mRNA expression. The GHRH antagonist JV-1-36 inhibits endometriotic cell proliferation and survival, suggesting that GHRH antagonist may represent promising tools for treatment of endometriosis. Copyright (c) 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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

1998-02-01

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

Identification of Receptor Ligands and Receptor Subtypes Using Antagonists in a Capillary Electrophoresis Single-Cell Biosensor Separation System

Science.gov (United States)

Fishman, Harvey A.; Orwar, Owe; Scheller, Richard H.; Zare, Richard N.

1995-08-01

A capillary electrophoresis system with single-cell biosensors as a detector has been used to separate and identify ligands in complex biological samples. The power of this procedure was significantly increased by introducing antagonists that inhibited the cellular response from selected ligand-receptor interactions. The single-cell biosensor was based on the ligand-receptor binding and G-protein-mediated signal transduction pathways in PC12 and NG108-15 cell lines. Receptor activation was measured as increases in cytosolic free calcium ion concentration by using fluorescence microscopy with the intracellular calcium ion indicator fluo-3 acetoxymethyl ester. Specifically, a mixture of bradykinin (BK) and acetylcholine (ACh) was fractionated and the components were identified by inhibiting the cellular response with icatibant (HOE 140), a selective antagonist to the BK B_2 receptor subtype (B_2BK), and atropine, an antagonist to muscarinic ACh receptor subtypes. Structurally related forms of BK were also identified based on inhibiting B_2BK receptors. Applications of this technique include identification of endogenous BK in a lysate of human hepatocellular carcinoma cells (Hep G2) and screening for bioactivity of BK degradation products in human blood plasma. The data demonstrate that the use of antagonists with a single-cell biosensor separation system aids identification of separated components and receptor subtypes.

Identification of Adenyl Cyclase Activity in a Disease Resistance Protein in Arabidopsis thaliana

KAUST Repository

Hussein, Rana

2012-11-01

Cyclic nucleotide, cAMP, is an important signaling molecule in animals and plants. However, in plants the enzymes that synthesize this second messenger, adenyl cyclases (ACs), remain elusive. Given the physiological importance of cAMP in signaling, particularly in response to biotic and abiotic stresses, it is thus important to identify and characterize ACs in higher plants. Using computational approaches, a disease resistance protein from Arabidopsis thaliana, At3g04220 was found to have an AC catalytic center motif. In an attempt to prove that this candidate has adenyl cyclases activity in vitro, the coding sequence of the putative AC catalytic domain of this protein was cloned and expressed in E. coli and the recombinant protein was purified. The nucleotide cyclase activity of the recombinant protein was examined using cyclic nucleotide enzyme immunoassays. In parallel, the expression of At3g04220 was measured in leaves under three different stress conditions in order to determine under which conditions the disease resistance protein could function. Results show that the purified recombinant protein has Mn2+ dependent AC activity in vitro, and the expression analysis supports a role for At3g04220 and cAMP in plant defense.

Highly potent antagonists of luteinizing hormone-releasing hormone free of edematogenic effects.

Science.gov (United States)

Bajusz, S; Kovacs, M; Gazdag, M; Bokser, L; Karashima, T; Csernus, V J; Janaky, T; Guoth, J; Schally, A V

1988-03-01

To eliminate the undesirable edematogenic effect of the luteinizing hormone-releasing hormone (LH-RH) antagonists containing basic D amino acids at position 6, exemplified by [Ac-D-Phe(pCl)1,2,D-Trp3,D-Arg6,D-Ala10]LH-RH [Phe(pCl) indicates 4-chlorophenylalanine], analogs with D-ureidoalkyl amino acids such as D-citrulline (D-Cit) or D-homocitrulline (D-Hci) at position 6 were synthesized and tested in several systems in vitro and in vivo. HPLC analysis revealed that the overall hydrophobicity of the D-Cit/D-Hci6 analogs was similar to that of the basic D-Arg6 antagonists. In vitro, most of the analogs completely inhibited LH-RH-mediated luteinizing hormone release in perfused rat pituitary cell systems at an antagonist to LH-RH molar ratio of 5:1. In vivo, the most active peptides, [Ac-D-Nal(2)1,D-Phe(pCl)2,D-Trp3,D-Cit6,D-Ala10]LH-RH [Nal(2) indicates 3-(2-naphthyl)alanine] and its D-Hci6 analog, caused 100% inhibition of ovulation in cycling rats in doses of 3 micrograms and suppressed the luteinizing hormone level in ovariectomized female rats for 47 hr when administered at doses of 25 micrograms. Characteristically, these peptides did not exert any edematogenic effects even at 1.5 mg/kg. These properties of the D-Cit/D-Hci6 antagonists may make them useful clinically.

Design and Synthesis of Fluorescent Acyclic Nucleoside Phosphonates as Potent Inhibitors of Bacterial Adenylate Cyclases

Czech Academy of Sciences Publication Activity Database

Břehová, Petra; Šmídková, Markéta; Skácel, Jan; Dračínský, Martin; Mertlíková-Kaiserová, Helena; Velasquez, M. P. S.; Watts, V. J.; Janeba, Zlatko

2016-01-01

Roč. 11, č. 22 (2016), s. 2534-2546 ISSN 1860-7179 R&D Projects: GA MV VG20102015046; GA MŠk LO1302 Institutional support: RVO:61388963 Keywords : adenylate cyclase toxin * acyclic nucleoside phosphonates * anthranilic acid Subject RIV: CC - Organic Chemistry Impact factor: 3.225, year: 2016

AM-37 and ST-36 Are Small Molecule Bombesin Receptor Antagonists

OpenAIRE

Terry W. Moody; Nicole Tashakkori; Samuel A. Mantey; Paola Moreno; Irene Ramos-Alvarez; Marcello Leopoldo; Robert T. Jensen

2017-01-01

While peptide antagonists for the gastrin-releasing peptide receptor (BB2R), neuromedin B receptor (BB1R), and bombesin (BB) receptor subtype-3 (BRS-3) exist, there is a need to develop non-peptide small molecule inhibitors for all three BBR. The BB agonist (BA)1 binds with high affinity to the BB1R, BB2R, and BRS-3. In this communication, small molecule BBR antagonists were evaluated using human lung cancer cells. AM-37 and ST-36 inhibited binding to human BB1R, BB2R, and BRS-3 with similar ...

Antagonistic activity Trichoderma harzianum Rifai on the causal agent of rice blast (Pyricularia grisea Sacc.

Directory of Open Access Journals (Sweden)

Ernesto Juniors Pérez Torres

2017-10-01

Full Text Available With the objective to evaluate the antagonistic activity of T. harzianum (strain A-34 on the causal agent of rice blast (P. grisea, were developed several in vitro experiments. It was evaluated the biocontrol mechanisms such as competition through mounted the percent inhibition of radial growth of hyphae of P. grisea from 24 to 240 hours and the antagonistic capacity. In addition, was evaluated micoparasitism to inclination the observation of events Microscopy winding, penetration, vacuolization, lysis, and antibiosis by observing 24 hours a confrontation between the hyphae of the phytopathogenic fungus and biological control agent. It was obtained at 120 hours 100 % inhibition of micelial growth of causal agent, what corresponded with the degree 1 of antagonistic capacity (scale and is recorded as a hyperparasitic action on P. grisea. It was evidenced an antibiotic effect of metabolites produced by T. harzianum (strain A-34 to 24 hours of confrontation, where there was time interaction between the hyphae of microorganisms with 14,3 % inhibition, also was evidence the micoparasitism events by penetration, vacuolization and lysis in the cells of phytopathogenic fungus. These results demonstrated the ability of T. harzianum (strain A-34 on causal agent of rice blast (P. grisea.

The discovery of tropane-derived CCR5 receptor antagonists.

Science.gov (United States)

Armour, Duncan R; de Groot, Marcel J; Price, David A; Stammen, Blanda L C; Wood, Anthony; Perros, Manos; Burt, Catherine

2006-04-01

The development of compound 1, a piperidine-based CCR5 receptor antagonist with Type I CYP2D6 inhibition, into the tropane-derived analogue 5, is described. This compound, which is devoid of CYP2D6 liabilities, is a highly potent ligand for the CCR5 receptor and has broad-spectrum activity against a range of clinically relevant HIV isolates. The identification of human ether a-go-go-related gene channel inhibition within this series is described and the potential for QTc interval prolongation discussed. Furthermore, structure activity relationship (SAR) around the piperidine moiety is also described.

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

LENUS (Irish Health Repository)

Dooley, Ruth

2012-02-01

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

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

LENUS (Irish Health Repository)

Dooley, Ruth

2011-08-22

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

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

Directory of Open Access Journals (Sweden)

Hatt Hanns

2011-08-01

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

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

Science.gov (United States)

Yamamoto, Kouichi; Okui, Rikuya; Yamatodani, Atsushi

2018-04-12

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

ANTAGONISTIC EFFECT OF FOUR FUNGAL ISOLATES TO GANODERMA BONINENSE, THE CAUSAL AGENT OF BASAL STEM ROT OF OIL PALM

Directory of Open Access Journals (Sweden)

OKKY SETYAWATI DHARMAPUTRA

1990-01-01

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.

Pituitary adenylate cyclase 1 receptor internalization and endosomal signaling mediate the pituitary adenylate cyclase activating polypeptide-induced increase in guinea pig cardiac neuron excitability.

Science.gov (United States)

Merriam, Laura A; Baran, Caitlin N; Girard, Beatrice M; Hardwick, Jean C; May, Victor; Parsons, Rodney L

2013-03-06

After G-protein-coupled receptor activation and signaling at the plasma membrane, the receptor complex is often rapidly internalized via endocytic vesicles for trafficking into various intracellular compartments and pathways. The formation of signaling endosomes is recognized as a mechanism that produces sustained intracellular signals that may be distinct from those generated at the cell surface for cellular responses including growth, differentiation, and survival. Pituitary adenylate cyclase activating polypeptide (PACAP; Adcyap1) is a potent neurotransmitter/neurotrophic peptide and mediates its diverse cellular functions in part through internalization of its cognate G-protein-coupled PAC1 receptor (PAC1R; Adcyap1r1). In the present study, we examined whether PAC1R endocytosis participates in the regulation of neuronal excitability. Although PACAP increased excitability in 90% of guinea pig cardiac neurons, pretreatment with Pitstop 2 or dynasore to inhibit clathrin and dynamin I/II, respectively, suppressed the PACAP effect. Subsequent addition of inhibitor after the PACAP-induced increase in excitability developed gradually attenuated excitability with no changes in action potential properties. Likewise, the PACAP-induced increase in excitability was markedly decreased at ambient temperature. Receptor trafficking studies with GFP-PAC1 cell lines demonstrated the efficacy of Pitstop 2, dynasore, and low temperatures at suppressing PAC1R endocytosis. In contrast, brefeldin A pretreatments to disrupt Golgi vesicle trafficking did not blunt the PACAP effect, and PACAP/PAC1R signaling still increased neuronal cAMP production even with endocytic blockade. Our results demonstrate that PACAP/PAC1R complex endocytosis is a key step for the PACAP modulation of cardiac neuron excitability.

Different strictuctural requirements for adenylate cyclase toxin interactions with erythrocyte and liposome membranes

Czech Academy of Sciences Publication Activity Database

Mašín, Jiří; Konopásek, I.; Svobodová, J.; Šebo, Peter

2004-01-01

Roč. 1660, - (2004), s. 144-154 ISSN 0005-2736 R&D Projects: GA AV ČR IPP1050128; GA AV ČR IAA5020907 Grant - others:GA Howard Hughes Medical Institut(US) 55000334; GA(XE) QLK2-CT-1999-00556 Institutional research plan: CEZ:AV0Z5020903 Keywords : bordetella pertussis * adenylate cyclase toxin * membrane interaction Subject RIV: EE - Microbiology, Virology Impact factor: 3.441, year: 2004

Bordetella adenylate cyclase toxin is a unique ligand of the integrin complement receptor 3

Czech Academy of Sciences Publication Activity Database

Osička, Radim; Osičková, Adriana; Hasan, Shakir; Bumba, Ladislav; Černý, Jiří; Šebo, Peter

2015-01-01

Roč. 4, DEC 9 (2015) ISSN 2050-084X R&D Projects: GA ČR(CZ) GAP302/11/0580; GA ČR(CZ) GA15-11851S; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 ; RVO:86652036 Keywords : E. coli * adenylate cyclase toxin * biochemistry Subject RIV: CE - Biochemistry Impact factor: 8.282, year: 2015

Synthesis of alpha-Branched Acyclic Nucleoside Phosphonates as Potential Inhibitors of Bacterial Adenylate Cyclases

Czech Academy of Sciences Publication Activity Database

Frydrych, Jan; Skácel, Jan; Šmídková, Markéta; Mertlíková-Kaiserová, Helena; Dračínský, Martin; Gnanasekaran, Ramachandran; Lepšík, Martin; Soto-Velasquez, M.; Watts, V. J.; Janeba, Zlatko

2018-01-01

Roč. 13, č. 2 (2018), s. 199-206 ISSN 1860-7179 R&D Projects: GA MV VG20102015046; GA ČR(CZ) GBP208/12/G016; GA MŠk LO1302 Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonates * adenylate cyclase toxin * bisamidates * Bordetella pertussis * prodrugs Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 3.225, year: 2016

Effect of drugs on lipid methylation, receptor-adenylate cyclase coupling and cyclic AMP secretion in Dictyostelium discoideum

NARCIS (Netherlands)

Van Waarde, Aren; Van Haastert, P.J.M.

1986-01-01

Intercellular communication in Dictyostelium discoldeum takes place by means of cyclic AMP-induced cyclic AMP-synthesis and secretion. Since phospholipid methylation has been suggested to play a role in receptor-adenylate cyclase coupling, we examined the effects of transmethylation inhibitors on

The inhibition of cholera toxin-induced 5-HT release by the 5-HT3 receptor antagonist, granisetron, in the rat

Science.gov (United States)

Turvill, J L; Connor, P; Farthing, M J G

2000-01-01

The secretagogue 5-hydroxytryptamine (5-HT) is implicated in the pathophysiology of cholera. 5-HT released from enterochromaffin cells after cholera toxin exposure is thought to activate non-neuronally (5-HT2 dependent) and neuronally (5-HT3 dependent) mediated water and electrolyte secretion. CT-secretion can be reduced by preventing the release of 5-HT. Enterochromaffin cells possess numerous receptors that, under basal conditions, modulate 5-HT release. These include basolateral 5-HT3 receptors, the activation of which is known to enhance 5-HT release. Until now, 5-HT3 receptor antagonists (e.g. granisetron) have been thought to inhibit cholera toxin-induced fluid secretion by blockading 5-HT3 receptors on secretory enteric neurones. Instead we postulated that they act by inhibiting cholera toxin-induced enterochromaffin cell degranulation. Isolated intestinal segments in anaesthetized male Wistar rats, pre-treated with granisetron 75 μg kg−1, lidoocaine 6 mg kg−1 or saline, were instilled with a supramaximal dose of cholera toxin or saline. Net fluid movement was determined by small intestinal perfusion or gravimetry and small intestinal and luminal fluid 5-HT levels were determined by HPLC with fluorimetric detection. Intraluminal 5-HT release was proportional to the reduction in tissue 5-HT levels and to the onset of water and electrolyte secretion, suggesting that luminal 5-HT levels reflect enterochromaffin cell activity. Both lidocaine and granisetron inhibited fluid secretion. However, granisetron alone, and proportionately, reduced 5-HT release. The simultaneous inhibition of 5-HT release and fluid secretion by granisetron suggests that 5-HT release from enterochromaffin cells is potentiated by endogenous 5-HT3 receptors. The accentuated 5-HT release promotes cholera toxin-induced fluid secretion. PMID:10882387

Application of adenylate energy charge to problems of environmental impact assessment in aquatic organisms

Science.gov (United States)

Ivanovici, A. M.

1980-03-01

Various physiological and biochemical methods have been proposed for assessing the effects of environmental perturbation on aquatic organisms. The success of these methods as diagnostic tools has, however, been limited. This paper proposes that adenylate energy charge overcomes some of these limitations. The adenylate energy charge (AEC) is calculated from concentrations of adenine nucleotides ([ATP+½ADP]/[ATP+ADP+AMP]), and is a reflection of metabolic potential available to an organism. Several features of this method are: correlation of specific values with physiological condition or growth state, a defined range of values, fast response times and high precision. Several examples from laboratory and field experiments are given to demonstrate these features. The test organisms used (mollusc species) were exposed to a variety of environmental perturbations, including salinity reduction, hydrocarbons and low doses of heavy metal. The studies performed indicate that the energy charge may be a useful measure in the assessment of environmental impact. Its use is restricted, however, as several limitations exist which need to be fully evaluated. Further work relating values to population characteristics of multicellular organisms needs to be completed before the method can become a predictive tool for management.

Forskolin- and dihydroalprenolol (DHA) binding sites and adenylate cyclase activity in heart of rats fed diets containing different oils

International Nuclear Information System (INIS)

Alam, S.Q.; Ren, Y.F.; Alam, B.S.

1987-01-01

The purpose of the present investigation was to determine if dietary lipids can induce changes in the adenylate cyclase system in rat heart. Three groups of male young Sprague-Dawley rats were fed for 6 weeks diets containing 10% corn oil (I), 8% coconut oil + 2% corn oil (II) or 10% menhaden oil (III). Adenylate cyclase activity (basal, fluoride-, isoproterenol-, and forskolin-stimulated) was higher in heart homogenates of rats in group III than in the other two groups. Concentration of the [ 3 H]-forskolin binding sites in the cardiac membranes were significantly higher in rats fed menhaden oil. The values (pmol/mg protein) were 4.8 +/- 0.2 (I), 4.5 +/- 0.7 (II) and 8.4 +/- 0.5 (III). There was no significant difference in the affinity of the forskolin binding sites among the 3 dietary groups. When measured at different concentrations of forskolin, the adenylate cyclase activity in cardiac membranes of rats fed menhaden oil was higher than in the other 2 groups. Concentrations of the [ 3 H]DHA binding sites were slightly higher but their affinity was lower in cardiac membranes of rats fed menhaden oil. The results suggest that diets containing fish oil increase the concentration of the forskolin binding sites and may also affect the characteristics of the β-adrenergic receptor in rat heart

Interaction of Bordetella adenylate cyclase toxin with complement receptor 3 involves multivalent glycan binding

Czech Academy of Sciences Publication Activity Database

Hasan, Shakir; Osičková, Adriana; Bumba, Ladislav; Novák, Petr; Šebo, Peter; Osička, Radim

2015-01-01

Roč. 589, č. 3 (2015), s. 374-379 ISSN 0014-5793 R&D Projects: GA ČR(CZ) GAP302/11/0580; GA ČR(CZ) GA15-09157S; GA ČR(CZ) GA15-11851S Institutional support: RVO:61388971 Keywords : Adenylate cyclase toxin * CD11b/CD18 * Complement receptor type 3 Subject RIV: CE - Biochemistry Impact factor: 3.519, year: 2015

Influence of histamine and serotonin antagonists on the growth of xenografted human colorectal tumors.

Science.gov (United States)

Barkla, D H; Tutton, P J

1981-12-01

Four lines of human colorectal cancer were established and serially propagated as subcutaneous xenographs in immunosuppressed inbred CBA/Lac mice. Established xenografts were then used to investigate the influence of a serotonin antagonist (BW 501c) and a histamine H2 receptor antagonists (Cimetidine) on xenograft growth. The growth of each of the four tumor lines was significantly inhibited by BW 501c throughout the treatment, whereas the growth of only two tumor lines was significantly inhibited by Cimetidine treatment. The response of individual tumor lines was not predictable on the basis of either tumor histopathology or the natural growth rate of the untreated xenograft. A number of alternative, but not mutually exclusive, hypotheses are suggested to explain the results. One hypothesis proposes that colorectal tumors are composed of subpopulations of tumor cells that are variously dependent on or independent of amine hormones. Another hypothesis is that tumor cells exhibit temporal changes in hormone sensitivity to amine hormones during treatment. Finally, it is suggested that serotonin and/or histamine H2 antagonists may be useful in preventing the repopulation of colorectal carcinomas following antineoplastic therapy with the use of conventional drugs.

Dual orexin receptor antagonist 12 inhibits expression of proteins in neurons and glia implicated in peripheral and central sensitization.

Science.gov (United States)

Cady, R J; Denson, J E; Sullivan, L Q; Durham, P L

2014-06-06

Sensitization and activation of trigeminal nociceptors is implicated in prevalent and debilitating orofacial pain conditions including temporomandibular joint (TMJ) disorders. Orexins are excitatory neuropeptides that function to regulate many physiological processes and are reported to modulate nociception. To determine the role of orexins in an inflammatory model of trigeminal activation, the effects of a dual orexin receptor antagonist (DORA-12) on levels of proteins that promote peripheral and central sensitization and changes in nocifensive responses were investigated. In adult male Sprague-Dawley rats, mRNA for orexin receptor 1 (OX₁R) and receptor 2 (OX₂R) were detected in trigeminal ganglia and spinal trigeminal nucleus (STN). OX₁R immunoreactivity was localized primarily in neuronal cell bodies in the V3 region of the ganglion and in laminas I-II of the STN. Animals injected bilaterally with complete Freund's adjuvant (CFA) in the TMJ capsule exhibited increased expression of P-p38, P-ERK, and lba1 in trigeminal ganglia and P-ERK and lba1 in the STN at 2 days post injection. However, levels of each of these proteins in rats receiving daily oral DORA-12 were inhibited to near basal levels. Similarly, administration of DORA-12 on days 3 and 4 post CFA injection in the TMJ effectively inhibited the prolonged stimulated expression of protein kinase A, NFkB, and Iba1 in the STN on day 5 post injection. While injection of CFA mediated a nocifensive response to mechanical stimulation of the orofacial region at 2h and 3 and 5 days post injection, treatment with DORA-12 suppressed the nocifensive response on day 5. Somewhat surprisingly, nocifensive responses were again observed on day 10 post CFA stimulation in the absence of daily DORA-12 administration. Our results provide evidence that DORA-12 can inhibit CFA-induced stimulation of trigeminal sensory neurons by inhibiting expression of proteins associated with sensitization of peripheral and central

A marine bacterium, Micrococcus MCCB 104, antagonistic to vibrios in prawn larval rearing systems.

Science.gov (United States)

Jayaprakash, N S; Pai, S Somnath; Anas, A; Preetha, R; Philip, Rosamma; Singh, I S Bright

2005-12-30

A marine bacterium, Micrococcus MCCB 104, isolated from hatchery water, demonstrated extracellular antagonistic properties against Vibrio alginolyticus, V. parahaemolyticus, V. vulnificus, V. fluviallis, V. nereis, V. proteolyticus, V. mediterranei, V cholerae and Aeromonas sp., bacteria associated with Macrobrachium rosenbergii larval rearing systems. The isolate inhibited the growth of V. alginolyticus during co-culture. The antagonistic component of the extracellular product was heat-stable and insensitive to proteases, lipase, catalase and alpha-amylase. Micrococcus MCCB 104 was demonstrated to be non-pathogenic to M. rosenbergii larvae.

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

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Jianhui Liu

2015-01-01

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.

Structural Studies of Archaealthermophilic Adenylate Kinase; TOPICAL

International Nuclear Information System (INIS)

Konisky, J.

2002-01-01

Through this DOE-sponsored program Konisky has studied the evolution and molecular biology of microbes that live in extreme environments. The emphasis of this work has been the determination of the structural features of thermophilic enzymes that allow them to function optimally at near 100 C. The laboratory has focused on a comparative study of adenylate kinase (ADK), an enzyme that functions to interconvert adenine nucleotides. Because of the close phylogenetic relatedness of members of the Methanococci, differences in the structure of their ADKs will be dominated by structural features that reflect contributions to their optimal temperature for activity, rather than differences due to phylogenetic divergence. We have cloned, sequenced and modeled the secondary structure for several methanococcal ADKs. Using molecular modeling threading approaches that are based on the solved structure for the porcine ADK, we have also proposed a general low resolution three dimensional structure for each of the methanococcal enzymes. These analyses have allowed us to propose structural features that confer hyperthermoactivity to those enzymes functioning in the hyperthermophilic members of the Methanococci. Using protein engineering methodologies, we have tested our hypotheses by examining the effects of selective structural changes on thermoactivity. Despite possessing between 68-81% sequence identity, the methanococcal AKs had significantly different stability against thermal denaturation, with melting points ranging from 69-103 C. The construction of several chimerical AKs by linking regions of the MVO and MJA AKs demonstrated the importance of cooperative interactions between amino- and carboxyl-terminal regions in influencing thermostability. Addition of MJA terminal fragments to the MVO AK increased thermal stability approximately 20 C while maintaining 88% of the mesophilic sequence. Further analysis using structural models suggested that hydrophobic interactions are

Adrenalectomy mediated alterations in adrenergic activation of adenylate cyclase in rat liver

International Nuclear Information System (INIS)

El-Refai, M.; Chan, T.

1986-01-01

Adrenalectomy caused a large increase in the number of β-adrenergic binding sites on liver plasma membranes as measured by 125 I-iodocyanopindolol (22 and 102 fmol/mg protein for control and adrenalectomized (ADX) rats). Concomitantly an increase in the number of binding sites for 3 H-yohimbine was also observed (104 and 175 fmol/mg protein for control and adx membranes). Epinephrine-stimulated increase in cyclic AMP accumulation in isolated hepatocytes were greater in cells from ADX rats. This increase in β-adrenergic mediated action was much less than what may be expected as a result of the increase in the β-adrenergic binding in ADX membranes. In addition phenoxybenzamine (10 μM) further augmented this action of epinephrine in both control and ADX cells. To test the hypothesis that the increase in the number of the inhibitory α 2 -adrenergic receptors in adrenalectomy is responsible for the muted β-adrenergic response, the authors injected rats with pertussis toxin (PT). This treatment may cause the in vivo ribosylation of the inhibitory binding protein (Ni). Adenylate cyclase (AC) activity in liver plasma membranes prepared from treated and untreated animals was measured. In contrast with control rats, treatment of ADX rats with PT resulted in a significant increase in the basal activity of AC (5.5 and 7.7 pmol/mg protein/min for untreated and treated rats respectively). Isoproterenol (10 μM), caused AC activity to increase to 6.5 and 8.4 pmol/mg protein/min for membranes obtained from ADX untreated and ADX treated rats respectively. The α-adrenergic antagonists had no significant effect on the β-adrenergic-mediated activation of AC in liver plasma membranes from PT treated control and ADX rats. The authors conclude that the β-adrenergic activation of AC is attenuated by Ni protein both directly and as a result of activation of α-adrenergic receptors

Mutation in the β-hairpin of the Bordetella pertussis adenylate cyclase toxin modulates N-lobe conformation in calmodulin

International Nuclear Information System (INIS)

Springer, Tzvia I.; Goebel, Erich; Hariraju, Dinesh; Finley, Natosha L.

2014-01-01

Highlights: • Bordetella pertussis adenylate cyclase toxin modulates bi-lobal structure of CaM. • The structure and stability of the complex rely on intermolecular associations. • A novel mode of CaM-dependent activation of the adenylate cyclase toxin is proposed. - Abstract: Bordetella pertussis, causative agent of whooping cough, produces an adenylate cyclase toxin (CyaA) that is an important virulence factor. In the host cell, the adenylate cyclase domain of CyaA (CyaA-ACD) is activated upon association with calmodulin (CaM), an EF-hand protein comprised of N- and C-lobes (N-CaM and C-CaM, respectively) connected by a flexible tether. Maximal CyaA-ACD activation is achieved through its binding to both lobes of intact CaM, but the structural mechanisms remain unclear. No high-resolution structure of the intact CaM/CyaA-ACD complex is available, but crystal structures of isolated C-CaM bound to CyaA-ACD shed light on the molecular mechanism by which this lobe activates the toxin. Previous studies using molecular modeling, biochemical, and biophysical experiments demonstrate that CyaA-ACD’s β-hairpin participates in site-specific interactions with N-CaM. In this study, we utilize nuclear magnetic resonance (NMR) spectroscopy to probe the molecular association between intact CaM and CyaA-ACD. Our results indicate binding of CyaA-ACD to CaM induces large conformational perturbations mapping to C-CaM, while substantially smaller structural changes are localized primarily to helices I, II, and IV, and the metal-binding sites in N-CaM. Site-specific mutations in CyaA-ACD’s β-hairpin structurally modulate N-CaM, resulting in conformational perturbations in metal binding sites I and II, while no significant structural modifications are observed in C-CaM. Moreover, dynamic light scattering (DLS) analysis reveals that mutation of the β-hairpin results in a decreased hydrodynamic radius (R h ) and reduced thermal stability in the mutant complex. Taken together

Mutation in the β-hairpin of the Bordetella pertussis adenylate cyclase toxin modulates N-lobe conformation in calmodulin

Energy Technology Data Exchange (ETDEWEB)

Springer, Tzvia I.; Goebel, Erich; Hariraju, Dinesh [Department of Microbiology, Miami University, Oxford, OH 45056 (United States); Finley, Natosha L., E-mail: finleynl@miamioh.edu [Department of Microbiology, Miami University, Oxford, OH 45056 (United States); Cell, Molecular, and Structural Biology Program, Miami University, Oxford, OH 45056 (United States)

2014-10-10

Highlights: • Bordetella pertussis adenylate cyclase toxin modulates bi-lobal structure of CaM. • The structure and stability of the complex rely on intermolecular associations. • A novel mode of CaM-dependent activation of the adenylate cyclase toxin is proposed. - Abstract: Bordetella pertussis, causative agent of whooping cough, produces an adenylate cyclase toxin (CyaA) that is an important virulence factor. In the host cell, the adenylate cyclase domain of CyaA (CyaA-ACD) is activated upon association with calmodulin (CaM), an EF-hand protein comprised of N- and C-lobes (N-CaM and C-CaM, respectively) connected by a flexible tether. Maximal CyaA-ACD activation is achieved through its binding to both lobes of intact CaM, but the structural mechanisms remain unclear. No high-resolution structure of the intact CaM/CyaA-ACD complex is available, but crystal structures of isolated C-CaM bound to CyaA-ACD shed light on the molecular mechanism by which this lobe activates the toxin. Previous studies using molecular modeling, biochemical, and biophysical experiments demonstrate that CyaA-ACD’s β-hairpin participates in site-specific interactions with N-CaM. In this study, we utilize nuclear magnetic resonance (NMR) spectroscopy to probe the molecular association between intact CaM and CyaA-ACD. Our results indicate binding of CyaA-ACD to CaM induces large conformational perturbations mapping to C-CaM, while substantially smaller structural changes are localized primarily to helices I, II, and IV, and the metal-binding sites in N-CaM. Site-specific mutations in CyaA-ACD’s β-hairpin structurally modulate N-CaM, resulting in conformational perturbations in metal binding sites I and II, while no significant structural modifications are observed in C-CaM. Moreover, dynamic light scattering (DLS) analysis reveals that mutation of the β-hairpin results in a decreased hydrodynamic radius (R{sub h}) and reduced thermal stability in the mutant complex. Taken

Combination cancer chemotherapy with one compound: pluripotent bradykinin antagonists.

Science.gov (United States)

Stewart, John M; Gera, Lajos; Chan, Daniel C; York, Eunice J; Simkeviciene, Vitalija; Bunn, Paul A; Taraseviciene-Stewart, Laimute

2005-08-01

Lung and prostate cancers are major health problems worldwide. Treatments with standard chemotherapy agents are relatively ineffective. Combination chemotherapy gives better treatment than a single agent because the drugs can inhibit the cancer in different pathways, but new therapeutic agents are needed for the treatment of both tumor types. Bradykinin (BK) antagonists offer advantages of combination therapy in one compound. These promising multitargeted anti-cancer compounds selectively stimulate apoptosis in cancers and also inhibit both angiogenesis and matrix metalloprotease (MMP) action in treated lung and prostate tumors in nude mice. The highly potent, metabolism-resistant bradykinin antagonist peptide dimer, B-9870 [SUIM-(DArg-Arg-Pro-Hyp-Gly-Igl-Ser-DIgl-Oic-Arg)2] (SUIM=suberimidyl; Hyp=4-hydroxyproline; Igl=alpha-(2-indanyl)glycine; Oic=octahydroindole-2-carboxylic acid) and its non-peptide mimetic, BKM-570 [2,3,4,5,6-pentafluorocinnamoyl-(o-2,6-dichlorobenzyl)-L-tyrosine-N-(4-amino-2,2,6,6-tetramethylpiperidyl)amide] are superior to the widely used but toxic chemotherapeutic drugs cisplatin and taxotere. In certain combinations, they act synergistically with standard anti-cancer drugs. Due to its structure and biological activity, BKM-570 is an attractive lead compound for derivatization and evaluation for lung and prostate cancer drugs.

Involvement of endogenous antioxidant systems in the protective activity of pituitary adenylate cyclase-activating polypeptide against hydrogen peroxide-induced oxidative damages in cultured rat astrocytes.

Science.gov (United States)

Douiri, Salma; Bahdoudi, Seyma; Hamdi, Yosra; Cubì, Roger; Basille, Magali; Fournier, Alain; Vaudry, Hubert; Tonon, Marie-Christine; Amri, Mohamed; Vaudry, David; Masmoudi-Kouki, Olfa

2016-06-01

Astroglial cells possess an array of cellular defense mechanisms, including superoxide dismutase (SOD) and catalase antioxidant enzymes, to prevent damages caused by oxidative stress. Nevertheless, astroglial cell viability and functionality can be affected by significant oxidative stress. We have previously shown that pituitary adenylate cyclase-activating polypeptide (PACAP) is a potent glioprotective agent that prevents hydrogen peroxide (H2 O2 )-induced apoptosis in cultured astrocytes. The purpose of this study was to investigate the potential protective effect of PACAP against oxidative-generated alteration of astrocytic antioxidant systems. Incubation of cells with subnanomolar concentrations of PACAP inhibited H2 O2 -evoked reactive oxygen species accumulation, mitochondrial respiratory burst, and caspase-3 mRNA level increase. PACAP also stimulated SOD and catalase activities in a concentration-dependent manner, and counteracted the inhibitory effect of H2 O2 on the activity of these two antioxidant enzymes. The protective action of PACAP against H2 O2 -evoked inhibition of antioxidant systems in astrocytes was protein kinase A, PKC, and MAP-kinase dependent. In the presence of H2 O2 , the SOD blocker NaCN and the catalase inhibitor 3-aminotriazole, both suppressed the protective effects of PACAP on SOD and catalase activities, mitochondrial function, and cell survival. Taken together, these results indicate that the anti-apoptotic effect of PACAP on astroglial cells can account for the activation of endogenous antioxidant enzymes and reduction in respiration rate, thus preserving mitochondrial integrity and preventing caspase-3 expression provoked by oxidative stress. Considering its powerful anti-apoptotic and anti-oxidative properties, the PACAPergic signaling system should thus be considered for the development of new therapeutical approaches to cure various pathologies involving oxidative neurodegeneration. We propose the following cascade for the

Alteration in adenylate cyclase response to aminergic stimulation following neonatal x-irradiation

International Nuclear Information System (INIS)

Chronister, R.B.; Palmer, G.C.; Gerbrandt, L.

1980-01-01

X-irradiation of the rat neonatal hippocampus produces severe alterations in the architectonic features of the mature hippocampus. The most prominent alteration is a marked depletion of the granule cells of the dentate gyrus, with a subsequent realignment of CA 4 cells. The present data also show that norepinephrine (NE), dopamine and histamine stimulation of adenylate cyclase activity is severely attenuated in the hippocampi of irradiated animals. This failure suggests that the NE fibers of irradiated subjects, although normal in content of NE, are not functional in some of their NE-effector actions

Biochemical Characterization of Putative Adenylate Dimethylallyltransferase and Cytokinin Dehydrogenase from Nostoc sp. PCC 7120.

Science.gov (United States)

Frébortová, Jitka; Greplová, Marta; Seidl, Michael F; Heyl, Alexander; Frébort, Ivo

2015-01-01

Cytokinins, a class of phytohormones, are adenine derivatives common to many different organisms. In plants, these play a crucial role as regulators of plant development and the reaction to abiotic and biotic stress. Key enzymes in the cytokinin synthesis and degradation in modern land plants are the isopentyl transferases and the cytokinin dehydrogenases, respectively. Their encoding genes have been probably introduced into the plant lineage during the primary endosymbiosis. To shed light on the evolution of these proteins, the genes homologous to plant adenylate isopentenyl transferase and cytokinin dehydrogenase were amplified from the genomic DNA of cyanobacterium Nostoc sp. PCC 7120 and expressed in Escherichia coli. The putative isopentenyl transferase was shown to be functional in a biochemical assay. In contrast, no enzymatic activity was detected for the putative cytokinin dehydrogenase, even though the principal domains necessary for its function are present. Several mutant variants, in which conserved amino acids in land plant cytokinin dehydrogenases had been restored, were inactive. A combination of experimental data with phylogenetic analysis indicates that adenylate-type isopentenyl transferases might have evolved several times independently. While the Nostoc genome contains a gene coding for protein with characteristics of cytokinin dehydrogenase, the organism is not able to break down cytokinins in the way shown for land plants.

Catecholamine-induced desensitization of adenylate cyclase coupled β-adrenergic receptors in turkey erythrocytes: evidence for a two-step mechanism

International Nuclear Information System (INIS)

Stadel, J.M.; Rebar, R.; Crooke, S.T.

1987-01-01

Preincubation of turkey erythrocytes with isoproterenol is associated with (1) 50-60% attenuation of agonist-stimulated adenylate cyclase activity, (2) altered mobility of the β-adrenergic receptor on sodium dodecyl sulfate-polyacrylamide gels, and (3) increased phosphorylation of the β-adrenergic receptor. Using a low-cross-linked polyacrylamide gel, the β-adrenergic receptor protein from isoproterenol-desensitized cells, labeled with 32 P or with the photoaffinity label 125 I-(p-azidobenzyl)carazolol, can be resolved into a doublet (M/sub r/ similarly ordered 37,000 and M/sub r/ similarly ordered 41,000) as compared to a single M/sub r/ similarly ordered 37,000 β-adrenergic receptor protein from control erythrocytes. The appearance of the doublet was dependent on the concentration of agonist used to desensitize the cells. Incubation of erythrocytes with dibutyryl-cAMP did not promote formation of the doublet but decreased agonist-stimulated adenylate cyclase activity 40-50%. Limited-digestion peptide maps of 32 P-labeled β-adrenergic receptors using papain revealed a unique phosphopeptide in the larger molecular weight band (M/sub r/ similarly ordered 41,000) of the doublet from the agonist-desensitized preparation that was absent in the peptide maps of the smaller band (M/sub r/ similarly ordered 37,000), as well as control or dibutyryl-cAMP-desensitized receptor. These data provide evidence that maximal agonist-induced desensitization of adenylate cyclase coupled β-adrenergic receptors in turkey erythrocytes occurs by a two-step mechanism

Involvement of PPAR-γ in the neuroprotective and anti-inflammatory effects of angiotensin type 1 receptor inhibition: effects of the receptor antagonist telmisartan and receptor deletion in a mouse MPTP model of Parkinson's disease

Directory of Open Access Journals (Sweden)

Garrido-Gil Pablo

2012-02-01

Full Text Available Abstract Background Several recent studies have shown that angiotensin type 1 receptor (AT1 antagonists such as candesartan inhibit the microglial inflammatory response and dopaminergic cell loss in animal models of Parkinson's disease. However, the mechanisms involved in the neuroprotective and anti-inflammatory effects of AT1 blockers in the brain have not been clarified. A number of studies have reported that AT1 blockers activate peroxisome proliferator-activated receptor gamma (PPAR γ. PPAR-γ activation inhibits inflammation, and may be responsible for neuroprotective effects, independently of AT1 blocking actions. Methods We have investigated whether oral treatment with telmisartan (the most potent PPAR-γ activator among AT1 blockers provides neuroprotection against dopaminergic cell death and neuroinflammation, and the possible role of PPAR-γ activation in any such neuroprotection. We used a mouse model of parkinsonism induced by the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP and co-administration of the PPAR-γ antagonist GW9662 to study the role of PPAR-γ activation. In addition, we used AT1a-null mice lesioned with MPTP to study whether deletion of AT1 in the absence of any pharmacological effect of AT1 blockers provides neuroprotection, and investigated whether PPAR-γ activation may also be involved in any such effect of AT1 deletion by co-administration of the PPAR-γ antagonist GW9662. Results We observed that telmisartan protects mouse dopaminergic neurons and inhibits the microglial response induced by administration of MPTP. The protective effects of telmisartan on dopaminergic cell death and microglial activation were inhibited by co-administration of GW9662. Dopaminergic cell death and microglial activation were significantly lower in AT1a-null mice treated with MPTP than in mice not subjected to AT1a deletion. Interestingly, the protective effects of AT1 deletion were also inhibited by co

Molecular approaches to contraceptive development

Indian Academy of Sciences (India)

Unknown

drugs; PACAP, pituitary adenyl cyclase activating peptide; PK, progesterone receptor; RA, retinoic acid. ... Institute for Research in Reproduction, JM Street, Parel, Mumbai 400 012, India .... antagonistic properties devoid of side effects such as.

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.

Antagonistic Activity of Probiotic Organism Against Vibrio cholerae and Cryptococcus neoformans

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Vidya, R.

2010-01-01

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.

Novel high-throughput screening system for identifying STAT3-SH2 antagonists

International Nuclear Information System (INIS)

Uehara, Yutaka; Mochizuki, Masato; Matsuno, Kenji; Haino, Takeharu; Asai, Akira

2009-01-01

Constitutive activation of the oncogenic transcription factor STAT3 frequently occurs in various human malignancies. STAT3 activation involves dimerization via intermolecular pTyr-SH2 interaction. Thus, antagonizing this interaction is a feasible approach to inhibit STAT3 activation for cancer therapy. In order to identify selective STAT3 inhibitors, we developed a biochemical HTS system based on AlphaScreen technology, which measures the abilities of test compounds to antagonize pTyr-SH2 interactions. We screened our chemical libraries using this system and identified 5,15-diphenylporphyrin (5,15-DPP) as a selective STAT3-SH2 antagonist. Selective inhibition of STAT3 nuclear translocation and DNA biding activity was observed in cells treated with 5,15-DPP. IL-6-dependent dimerization of STAT3, c-myc promoter binding and c-myc protein expression were all suppressed by 5,15-DPP, whereas no decrement in either expression or phosphorylation level of STAT3 was observed. Thus, the HTS assay system represented herein may be useful for identifying novel STAT3-SH2 antagonists.

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.

2001-01-01

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.......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....

In vivo PTH provokes apical NHE3 and NaPi2 redistribution and Na-K-ATPase inhibition

DEFF Research Database (Denmark)

Zhang, Y; Norian, J M; Magyar, C E

1999-01-01

and to determine whether the same cellular signals drive the changes in apical and basolateral transporters. PTH-(1-34) (20 U), which couples to adenylate cyclase (AC), phospholipase C (PLC), and phospholipase A2 (PLA2), or [Nle8,18,Tyr34]PTH-(3-34) (10 U), which couples to PLC and PLA2 but not AC, were given....../diuresis and NHE3 and NaPi2 internalization, and that Na-K-ATPase inhibition is not secondary to depressed apical Na+ transport....

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

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Živković Svetlana

2010-01-01

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. .

Segments Crucial for Membrane Translocation and Pore-forming Activity of Bordetella Adenylate Cyclase Toxin

Czech Academy of Sciences Publication Activity Database

Basler, Marek; Knapp, O.; Mašín, Jiří; Fišer, R.; Maier, E.; Benz, R.; Šebo, Peter; Osička, Radim

2007-01-01

Roč. 282, č. 17 (2007), s. 12419-12429 ISSN 0021-9258 R&D Projects: GA MŠk 1M0506; GA AV ČR IAA5020406 Grant - others:XE(XE) European Union 6th FP contract LSHB-CT-2003-503582 THERAVAC Institutional research plan: CEZ:AV0Z50200510 Source of funding: R - rámcový projekt EK Keywords : bordetella * adenylate cyclase toxin * ac membrane translocation Subject RIV: EE - Microbiology, Virology Impact factor: 5.581, year: 2007

Effects of sevoflurane on adenylate cyclase and phosphodiesterases activity in brain of rats

International Nuclear Information System (INIS)

Feng Changdong; Yang Jianping; Dai Tijun

2009-01-01

Objective: To investigate the effects of sevoflurane on c adenylate cyclase (AC) and phosphodiesterases (PDE) activity in the cerebrocortex, hippocampus and brain stem of rats, and to examine the role of cAMP in sevoflurane anesthesia. Methods: Fourty SD rats were delaminately designed and allocated randomly to 5 groups inhaling 1.5% sevoflurane i.e., no recovery (recovery group, n=8) and one hour after righting reflexrecovery (aware group, n=8). The brain tissues were rapidly dissected into cerebrocortex and hippocampus and brain stem.Then the adenylate cyclase and phosphodiesterases activity were assessed. Results: So far as the activity of AC is concerned, compared with the control group, the activity of AC in the cerebrocortex, hippocampus and brain stem brain stem of induction group and anesthesia group, the cerebrocortex, and hippocampus in the recovery group were significantly increased; compared with those in the anesthesia group, the activity of AC in the cerebrocortex, hippocampus and brain stem of aware group were significantly decreased (P<0.05); For the activity of PDE, compared with the control group, the activity of PDE in the cerebrocortex, hippocampus and brain stem in the induction group and anesthesia group was significantly decreased, compared with that in anesthesia group, the activity of PDE in the cerebrocortex, hippocampus and brain stem of recovery group and aware group was significantly increased (P<0.05). Conclusion: cAMP may play an important role in sevoflurane anesthesia. (authors)

Heterosubtypic protection against influenza A induced by adenylate cyclase toxoids delivering conserved HA2 subunit of hemagglutinin

Czech Academy of Sciences Publication Activity Database

Staneková, Z.; Adkins, Irena; Kosová, Martina; Janulíková, J.; Šebo, Peter; Varečková, E.

2013-01-01

Roč. 97, č. 1 (2013), s. 24-35 ISSN 0166-3542 R&D Projects: GA ČR GA310/08/0447; GA ČR GP310/09/P582 Institutional support: RVO:61388971 Keywords : Bordetella adenylate cyclase toxoid * Influenza A infection * Cross-protection Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 3.434, year: 2013

Amidate Prodrugs of 9-[2-(Phosphonomethoxy)Ethyl]Adenine as Inhibitors of Adenylate Cyclase Toxin from Bordetella pertussis

Czech Academy of Sciences Publication Activity Database

Šmídková, Markéta; Dvořáková, Alexandra; Tloušťová, Eva; Česnek, Michal; Janeba, Zlatko; Mertlíková-Kaiserová, Helena

2014-01-01

Roč. 58, č. 2 (2014), s. 664-671 ISSN 0066-4804 R&D Projects: GA MV VG20102015046 Grant - others:OPPC(XE) CZ.2.16/3.1.00/24016 Institutional support: RVO:61388963 Keywords : Bordetella pertussis * adenylate cyclase toxin * ACT * inhibitors * PMEA * amidate prodrugs Subject RIV: CC - Organic Chemistry Impact factor: 4.476, year: 2014

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

Directory of Open Access Journals (Sweden)

Miguel Muñoz

2010-04-01

Full Text Available 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.

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: mmunoz@cica.es; 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)

2010-04-20

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.

Structure-Function Relationships Underlying the Capacity of Bordetella Adenylate Cyclase Toxin to Disarm Host Phagocytes

Czech Academy of Sciences Publication Activity Database

Novák, Jakub; Černý, Ondřej; Osičková, Adriana; Linhartová, Irena; Mašín, Jiří; Bumba, Ladislav; Šebo, Peter; Osička, Radim

2017-01-01

Roč. 9, č. 10 (2017), s. 1-28, č. článku 300. E-ISSN 2072-6651 R&D Projects: GA ČR GA15-09157S; GA ČR(CZ) GA16-05919S; GA MŠk(CZ) LM2015064; GA MZd(CZ) NV16-28126A Institutional support: RVO:61388971 Keywords : adenylate cyclase toxin * Bordetella * cAMP Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.030, year: 2016

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

International Nuclear Information System (INIS)

McCormick, Patrick N.; Kapur, Shitij; Seeman, Philip; Wilson, Alan A.

2008-01-01

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 [ 11 C](+)-PHNO ([ 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 [ 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 [ 11 C](+)-PHNO and [ 3 H]raclopride. Rats were sacrificed 60 min after radiotracer injection. Striatum, cerebellum and plasma samples were counted for 11 C and 3 H. The specific binding ratio {SBR, i.e., [%ID/g (striatum)-%ID/g (cerebellum)]/(%ID/g (cerebellum)} was used as the outcome measure. Results: In response to D2 antagonists, partial agonist or full agonist, [ 11 C](+)-PHNO and [ 3 H]raclopride SBRs responded indistinguishably in terms of both ED 50 and Hill slope (e.g., (-)-NPA ED 50 values are 0.027 and 0.023 mg/kg for [ 11 C](+)-PHNO and [ 3 H]raclopride, respectively). In response to AMPH challenge, [ 11 C](+)-PHNO and [ 3 H]raclopride SBRs were inhibited to the same degree. Conclusions: We have shown that the SBRs of [ 11 C](+)-PHNO- and [ 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 applicability of the D2 two-state model, as described by in vitro binding experiments

Molecular requirements for inhibition of the chemokine receptor CCR8--probe-dependent allosteric interactions

DEFF Research Database (Denmark)

Rummel, Pia Cwarzko; Arfelt, K N; Baumann, L

2012-01-01

Here we present a novel series of CCR8 antagonists based on a naphthalene-sulfonamide structure. This structure differs from the predominant pharmacophore for most small-molecule CC-chemokine receptor antagonists, which in fact activate CCR8, suggesting that CCR8 inhibition requires alternative...

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

Science.gov (United States)

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

2004-10-01

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.

Adenylate Cyclases of Trypanosoma brucei, Environmental Sensors and Controllers of Host Innate Immune Response.

Science.gov (United States)

Salmon, Didier

2018-04-25

Trypanosoma brucei , etiological agent of Sleeping Sickness in Africa, is the prototype of African trypanosomes, protozoan extracellular flagellate parasites transmitted by saliva ( Salivaria ). In these parasites the molecular controls of the cell cycle and environmental sensing are elaborate and concentrated at the flagellum. Genomic analyses suggest that these parasites appear to differ considerably from the host in signaling mechanisms, with the exception of receptor-type adenylate cyclases (AC) that are topologically similar to receptor-type guanylate cyclase (GC) of higher eukaryotes but control a new class of cAMP targets of unknown function, the cAMP response proteins (CARPs), rather than the classical protein kinase A cAMP effector (PKA). T. brucei possesses a large polymorphic family of ACs, mainly associated with the flagellar membrane, and these are involved in inhibition of the innate immune response of the host prior to the massive release of immunomodulatory factors at the first peak of parasitemia. Recent evidence suggests that in T. brucei several insect-specific AC isoforms are involved in social motility, whereas only a few AC isoforms are involved in cytokinesis control of bloodstream forms, attesting that a complex signaling pathway is required for environmental sensing. In this review, after a general update on cAMP signaling pathway and the multiple roles of cAMP, I summarize the existing knowledge of the mechanisms by which pathogenic microorganisms modulate cAMP levels to escape immune defense.

Adenylate Cyclases of Trypanosoma brucei, Environmental Sensors and Controllers of Host Innate Immune Response

Directory of Open Access Journals (Sweden)

Didier Salmon

2018-04-01

Full Text Available Trypanosoma brucei, etiological agent of Sleeping Sickness in Africa, is the prototype of African trypanosomes, protozoan extracellular flagellate parasites transmitted by saliva (Salivaria. In these parasites the molecular controls of the cell cycle and environmental sensing are elaborate and concentrated at the flagellum. Genomic analyses suggest that these parasites appear to differ considerably from the host in signaling mechanisms, with the exception of receptor-type adenylate cyclases (AC that are topologically similar to receptor-type guanylate cyclase (GC of higher eukaryotes but control a new class of cAMP targets of unknown function, the cAMP response proteins (CARPs, rather than the classical protein kinase A cAMP effector (PKA. T. brucei possesses a large polymorphic family of ACs, mainly associated with the flagellar membrane, and these are involved in inhibition of the innate immune response of the host prior to the massive release of immunomodulatory factors at the first peak of parasitemia. Recent evidence suggests that in T. brucei several insect-specific AC isoforms are involved in social motility, whereas only a few AC isoforms are involved in cytokinesis control of bloodstream forms, attesting that a complex signaling pathway is required for environmental sensing. In this review, after a general update on cAMP signaling pathway and the multiple roles of cAMP, I summarize the existing knowledge of the mechanisms by which pathogenic microorganisms modulate cAMP levels to escape immune defense.

Naftopidil inhibits 5-hydroxytryptamine-induced bladder contraction in rats.

Science.gov (United States)

Sakai, Takumi; Kasahara, Ken-ichi; Tomita, Ken-ichi; Ikegaki, Ichiro; Kuriyama, Hiroshi

2013-01-30

Naftopidil is an α(1D) and α(1A) subtype-selective α(1)-adrenoceptor antagonist that has been used to treat lower urinary tract symptoms of benign prostatic hyperplasia. In this study, we investigated the effects of naftopidil on 5-hydroxytryptamine (5-HT)-induced rat bladder contraction (10(-8)-10(-4) M). Naftopidil (0.3, 1, and 3 μM) inhibited 5-HT-induced bladder contraction in a concentration-dependent manner. On the other hand, other α(1)-adrenoceptor antagonists, tamsulosin, silodosin or prazosin, did not inhibit 5-HT-induced bladder contraction. The 5-HT-induced bladder contraction was inhibited by both ketanserin and 4-(4-fluoronaphthalen-1-yl)-6-propan-2-ylpyrimidin-2-amine (RS127445), serotonin 5-HT(2A) and 5-HT(2B) receptor antagonists, respectively. In addition, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and α-methyl-5-HT, 5-HT(2A) and 5-HT(2) receptor agonists, respectively, induced bladder contraction. The 5-HT-induced bladder contraction was not inhibited by N-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-N-pyridin-2-yl-cyclohexanecarboxamide (WAY-100635), [1-[2[(methylsulfonyl)amino]ethyl]-4-piperidinyl]methyl-1-methyl-1H-indole-3-carboxylate (GR113808) or (R)-3-[2-[2-(4-methylpiperidin-1-yl)ethyl]pyrrolidine-1-sulphonyl]phenol (SB269970), 5-HT(1A), 5-HT(4) and 5-HT(7) receptor antagonists, respectively. Naftopidil inhibited both the 5-HT(2A) and 5-HT(2) receptor agonists-induced bladder contractions. Naftopidil binds to the human 5-HT(2A) and 5-HT(2B) receptors with pKi values of 6.55 and 7.82, respectively. These results suggest that naftopidil inhibits 5-HT-induced bladder contraction via blockade of the 5-HT(2A) and 5-HT(2B) receptors in rats. Furthermore, 5-HT-induced bladder contraction was enhanced in bladder strips obtained from bladder outlet obstructed rats, with this contraction inhibited by naftopidil. The beneficial effects of naftopidil on storage symptoms such as urinary frequency and nocturia in patients with benign

Isolation, identification, and biocontrol of antagonistic bacterium against Botrytis cinerea after tomato harvest

Directory of Open Access Journals (Sweden)

Jun-Feng Shi

Full Text Available ABSTRACT Tomato is one of the most important vegetables in the world. Decay after harvest is a major issue in the development of tomato industry. Currently, the most effective method for controlling decay after harvest is storage of tomato at low temperature combined with usage of chemical bactericide; however, long-term usage of chemical bactericide not only causes pathogen resistance but also is harmful for human health and environment. Biocontrol method for the management of disease after tomato harvest has great practical significance. In this study, antagonistic bacterium B-6-1 strain was isolated from the surface of tomato and identified as Enterobacter cowanii based on morphological characteristics and physiological and biochemical features combined with sequence analysis of 16SrDNA and ropB gene and construction of dendrogram. Effects of different concentrations of antagonistic bacterium E. cowanii suspension on antifungal activity after tomato harvest were analyzed by mycelium growth rate method. Results revealed that antifungal activity was also enhanced with increasing concentrations of antagonistic bacterium; inhibitory rates of 1 × 105 colony-forming units (cfu/mL antagonistic bacterial solution on Fusarium verticillioides, Alternaria tenuissima, and Botrytis cinerea were 46.31%, 67.48%, and 75.67%, respectively. By using in vivo inoculation method, it was further confirmed that antagonistic bacterium could effectively inhibit the occurrence of B. cinerae after tomato harvest, biocontrol effect of 1 × 109 cfu/mL zymotic fluid reached up to 95.24%, and antagonistic bacterium E. cowanii has biocontrol potential against B. cinerea after harvest of fruits and vegetables.

Decreased angiogenesis and arthritic disease in rabbits treated with an αvβ3 antagonist

Science.gov (United States)

Storgard, Chris M.; Stupack, Dwayne G.; Jonczyk, Alfred; Goodman, Simon L.; Fox, Robert I.; Cheresh, David A.

1999-01-01

Rheumatoid arthritis (RA) is an inflammatory disease associated with intense angiogenesis and vascular expression of integrin αvβ3. Intra-articular administration of a cyclic peptide antagonist of integrin αvβ3 to rabbits with antigen-induced arthritis early in disease resulted in inhibition of synovial angiogenesis and reduced synovial cell infiltrate, pannus formation, and cartilage erosions. These effects were not associated with lymphopenia or impairment of leukocyte function. Furthermore, when administered in chronic, preexisting disease, the αvβ3 antagonist effectively diminished arthritis severity and was associated with a quantitative increase in apoptosis of the angiogenic blood vessels. Therefore, angiogenesis appears to be a central factor in the initiation and persistence of arthritic disease, and antagonists of integrin αvβ3 may represent a novel therapeutic strategy for RA. PMID:9884333

Selective splitting of 3'-adenylated dinucleoside polyphosphates by specific enzymes degrading dinucleoside polyphosphates.

Science.gov (United States)

Guranowski, Andrzej; Sillero, Antonio; Günther Sillero, María Antonia

2003-01-01

Several 3'-[(32)P]adenylated dinucleoside polyphosphates (Np(n)N'p*As) were synthesized by the use of poly(A) polymerase (Sillero MAG et al., 2001, Eur J Biochem.; 268: 3605-11) and three of them, ApppA[(32)P]A or ApppAp*A, AppppAp*A and GppppGp*A, were tested as potential substrates of different dinucleoside polyphosphate degrading enzymes. Human (asymmetrical) dinucleoside tetraphosphatase (EC 3.6.1.17) acted almost randomly on both AppppAp*A, yielding approximately equal amounts of pppA + pAp*A and pA + pppAp*A, and GppppGp*, yielding pppG + pGp*A and pG + pppGp*A. Narrow-leafed lupin (Lupinus angustifolius) tetraphosphatase acted preferentially on the dinucleotide unmodified end of both AppppAp*A (yielding 90% of pppA + pAp*A and 10 % of pA + pppAp*A) and GppppGp*A (yielding 89% pppG + pGp*A and 11% of pG + pppGp*A). (Symmetrical) dinucleoside tetraphosphatase (EC 3.6.1.41) from Escherichia coli hydrolyzed AppppAp*A and GppppGp*A producing equal amounts of ppA + ppAp*A and ppG + ppGp*A, respectively, and, to a lesser extent, ApppAp*A producing pA + ppAp*A. Two dinucleoside triphosphatases (EC 3.6.1.29) (the human Fhit protein and the enzyme from yellow lupin (Lupinus luteus)) and dinucleoside tetraphosphate phosphorylase (EC 2.7.7.53) from Saccharomyces cerevisiae did not degrade the three 3'-adenylated dinucleoside polyphosphates tested.

Docosahexaenoic acid alters Gsα localization in lipid raft and potentiates adenylate cyclase.

Science.gov (United States)

Zhu, Zhuoran; Tan, Zhoubin; Li, Yan; Luo, Hongyan; Hu, Xinwu; Tang, Ming; Hescheler, Jürgen; Mu, Yangling; Zhang, Lanqiu

2015-01-01

Supplementation with docosahexaenoic acid (DHA), an ω-3 polyunsaturated fatty acid (PUFA), recently has become popular for the amelioration of depression; however the molecular mechanism of DHA action remains unclear. The aim of this study was to investigate the mechanism underlying the antidepressant effect of DHA by evaluating Gsα localization in lipid raft and the activity of adenylate cyclase in an in vitro glioma cell model. Lipid raft fractions from C6 glioma cells treated chronically with DHA were isolated by sucrose gradient ultracentrifugation. The content of Gsα in lipid raft was analyzed by immunoblotting and colocalization of Gsα with lipid raft was subjected to confocal microscopic analysis. The intracellular cyclic adenosine monophosphate (cAMP) level was determined by cAMP immunoassay kit. DHA decreased the amount of Gsα in lipid raft, whereas whole cell lysate Gsα was not changed. Confocal microscopic analysis demonstrated that colocalization of Gsα with lipid raft was decreased, whereas DHA increased intracellular cAMP accumulation in a dose-dependent manner. Interestingly, we found that DHA increased the lipid raft level, instead of disrupting it. The results of this study suggest that DHA may exert its antidepressant effect by translocating Gsα from lipid raft and potentiating the activity of adenylate cyclase. Importantly, the reduced Gsα in lipid raft by DHA is independent of disruption of lipid raft. Overall, the study provides partial preclinical evidence supporting a safe and effective therapy using DHA for depression. Copyright © 2015 Elsevier Inc. All rights reserved.

Discovery, synthesis, selectivity modulation and DMPK characterization of 5-azaspiro[2.4]heptanes as potent orexin receptor antagonists.

Science.gov (United States)

Stasi, Luigi Piero; Artusi, Roberto; Bovino, Clara; Buzzi, Benedetta; Canciani, Luca; Caselli, Gianfranco; Colace, Fabrizio; Garofalo, Paolo; Giambuzzi, Silvia; Larger, Patrice; Letari, Ornella; Mandelli, Stefano; Perugini, Lorenzo; Pucci, Sabrina; Salvi, Matteo; Toro, PierLuigi

2013-05-01

Starting from a orexin 1 receptor selective antagonist 4,4-disubstituted piperidine series a novel potent 5-azaspiro[2.4]heptane dual orexin 1 and orexin 2 receptor antagonist class has been discovered. SAR and Pharmacokinetic optimization of this series is herein disclosed. Lead compound 15 exhibits potent activity against orexin 1 and orexin 2 receptors along with low cytochrome P450 inhibition potential, good brain penetration and oral bioavailability in rats. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pore formation by the Bordetella adenylate cyclase toxin in lipid bilayer membranes: Role of voltage and pH

Czech Academy of Sciences Publication Activity Database

Knapp, O.; Maier, E.; Mašín, Jiří; Šebo, Peter; Benz, R.

2008-01-01

Roč. 1778, č. 1 (2008), s. 260-269 ISSN 0005-2736 R&D Projects: GA AV ČR(CZ) IAA5020406 Grant - others:XE(XE) QLK2-CT-1999-00556 Institutional research plan: CEZ:AV0Z50200510 Keywords : adenylate cyclase toxin * act * voltage Subject RIV: EE - Microbiology, Virology Impact factor: 4.180, year: 2008

Presynaptic inhibition of spontaneous acetylcholine release induced by adenosine at the mouse neuromuscular junction.

Science.gov (United States)

De Lorenzo, Silvana; Veggetti, Mariela; Muchnik, Salomón; Losavio, Adriana

2004-05-01

1. At the mouse neuromuscular junction, adenosine (AD) and the A(1) agonist 2-chloro-N(6)-cyclopentyl-adenosine (CCPA) induce presynaptic inhibition of spontaneous acetylcholine (ACh) release by activation of A(1) AD receptors through a mechanism that is still unknown. To evaluate whether the inhibition is mediated by modulation of the voltage-dependent calcium channels (VDCCs) associated with tonic secretion (L- and N-type VDCCs), we measured the miniature end-plate potential (mepp) frequency in mouse diaphragm muscles. 2. Blockade of VDCCs by Cd(2+) prevented the effect of the CCPA. Nitrendipine (an L-type VDCC antagonist) but not omega-conotoxin GVIA (an N-type VDCC antagonist) blocked the action of CCPA, suggesting that the decrease in spontaneous mepp frequency by CCPA is associated with an action on L-type VDCCs only. 3. As A(1) receptors are coupled to a G(i/o) protein, we investigated whether the inhibition of PKA or the activation of PKC is involved in the presynaptic inhibition mechanism. Neither N-(2[p-bromocinnamylamino]-ethyl)-5-isoquinolinesulfonamide (H-89, a PKA inhibitor), nor 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine (H-7, a PKC antagonist), nor phorbol 12-myristate 13-acetate (PHA, a PKC activator) modified CCPA-induced presynaptic inhibition, suggesting that these second messenger pathways are not involved. 4. The effect of CCPA was eliminated by the calmodulin antagonist N-(6-aminohexil)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) and by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid-acetoxymethyl ester epsilon6TDelta-BM, which suggests that the action of CCPA to modulate L-type VDCCs may involve Ca(2+)-calmodulin. 5. To investigate the action of CCPA on diverse degrees of nerve terminal depolarization, we studied its effect at different external K(+) concentrations. The effect of CCPA on ACh secretion evoked by 10 mm K(+) was prevented by the P/Q-type VDCC antagonist omega-agatoxin IVA. 6. CCPA failed to

Viability of D283 medulloblastoma cells treated with a histone deacetylase inhibitor combined with bombesin receptor antagonists.

Science.gov (United States)

Jaeger, Mariane; Ghisleni, Eduarda C; Fratini, Lívia; Brunetto, Algemir L; Gregianin, Lauro José; Brunetto, André T; Schwartsmann, Gilberto; de Farias, Caroline B; Roesler, Rafael

2016-01-01

Medulloblastoma (MB) comprises four distinct molecular subgroups, and survival remains particularly poor in patients with Group 3 tumors. Mutations and copy number variations result in altered epigenetic regulation of gene expression in Group 3 MB. Histone deacetylase inhibitors (HDACi) reduce proliferation, promote cell death and neuronal differentiation, and increase sensitivity to radiation and chemotherapy in experimental MB. Bombesin receptor antagonists potentiate the antiproliferative effects of HDACi in lung cancer cells and show promise as experimental therapies for several human cancers. Here, we examined the viability of D283 cells, which belong to Group 3 MB, treated with an HDACi alone or combined with bombesin receptor antagonists. D283 MB cells were treated with different doses of the HDACi sodium butyrate (NaB), the neuromedin B receptor (NMBR) antagonist BIM-23127, the gastrin releasing peptide receptor (GRPR) antagonist RC-3095, or combinations of NaB with each receptor antagonist. Cell viability was examined by cell counting. NaB alone or combined with receptor antagonists reduced cell viability at all doses tested. BIM-23127 alone did not affect cell viability, whereas RC-3095 at an intermediate dose significantly increased cell number. Although HDACi are promising agents to inhibit MB growth, the present results provide preliminary evidence that combining HDACi with bombesin receptor antagonists is not an effective strategy to improve the effects of HDACi against MB cells.

Comparative analysis of oligonucleotide primers for high-throughput screening of genes encoding adenylation domains of nonribosomal peptide synthetases in actinomycetes

Czech Academy of Sciences Publication Activity Database

Bakal, Tomáš; Goo, K.-S.; Najmanová, Lucie; Plháčková, Kamila; Kadlčík, Stanislav; Ulanová, Dana

2015-01-01

Roč. 108, č. 5 (2015), s. 1267-1274 ISSN 0003-6072 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : Nonribosomal peptide synthetase * Adenylation domain * Actinomycetes Subject RIV: EE - Microbiology, Virology Impact factor: 1.944, year: 2015

Evidence that diclofenac and celecoxib are thyroid hormone receptor beta antagonists.

Science.gov (United States)

Zloh, Mire; Perez-Diaz, Noelia; Tang, Leslie; Patel, Pryank; Mackenzie, Louise S

2016-02-01

Long term use of NSAIDs is linked to side effects such as gastric bleeding and myocardial infarction. Use of in silico methods and pharmacology to investigate the potential for NSAIDs diclofenac, celecoxib and naproxen to bind to nuclear receptors. In silico screening predicted that both diclofenac and celecoxib has the potential to bind to a number of different nuclear receptors; docking analysis confirmed a theoretical ability for diclofenac and celecoxib but not naproxen to bind to TRβ. Results from TRβ luciferase reporter assays confirmed that both diclofenac and celecoxib display TRβ antagonistic properties; celecoxib, IC50 3.6 × 10(-6)M, and diclofenac IC50 5.3 × 10(-6)M, comparable to the TRβ antagonist MLS (IC50 3.1 × 10(-6)M). In contrast naproxen, a cardio-sparing NSAID, lacked TRβ antagonist effects. In order to determine the effects of NSAIDs in whole organ in vitro, we used isometric wire myography to measure the changes to Triiodothyronine (T3) induced vasodilation of rat mesenteric arteries. Incubation of arteries in the presence of the TRβ antagonist MLS000389544 (10(-5)M), as well as diclofenac (10(-5)M) and celecoxib (10(-5)M) but not naproxen significantly inhibited T3 induced vasodilation compared to controls. These results highlight the benefits of computational chemistry methods used to retrospectively analyse well known drugs for side effects. Using in silico and in vitro methods we have shown that both celecoxib and diclofenac but not naproxen exhibit off-target TRβ antagonist behaviour, which may be linked to their detrimental side effects. Copyright © 2016 Elsevier Inc. All rights reserved.

Inhibition of radiation-induced polyuria by histamine receptor antagonists

Energy Technology Data Exchange (ETDEWEB)

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

1986-03-01

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

Inhibition of radiation-induced polyuria by histamine receptor antagonists

International Nuclear Information System (INIS)

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

1986-01-01

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

Antagonist profile of ibodutant at the tachykinin NK2 receptor in guinea pig isolated bronchi.

Science.gov (United States)

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

2013-10-24

In this study we have characterized the pharmacological profile of the non-peptide tachykinin NK 2 receptor antagonist ibodutant (MEN15596) in guinea pig isolated main bronchi contractility. The antagonist potency of ibodutant was evaluated using the selective NK 2 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 pK B 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 IC 50 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 NK 2 receptor antagonist in guinea pig airways. © 2013 Published by Elsevier B.V.

Prokaryotic adenylate cyclase toxin stimulates anterior pituitary cells in culture

International Nuclear Information System (INIS)

Cronin, M.J.; Evans, W.S.; Rogol, A.D.; Weiss, A.A.; Thorner, M.O.; Orth, D.N.; Nicholson, W.E.; Yasumoto, T.; Hewlett, E.L.

1986-01-01

Bordetella pertussis synthesis a variety of virulence factors including a calmodulin-dependent adenylate cyclase (AC) toxin. Treatment of anterior pituitary cells with this AC toxin resulted in an increase in cellular cAMP levels that was associated with accelerated exocytosis of growth hormone (GH), prolactin, adrenocorticotropic hormone (ACTH), and luteinizing hormone (LH). The kinetics of release of these hormones, however, were markedly different; GH and prolactin were rapidly released, while LH and ACTH secretion was more gradually elevated. Neither dopamine agonists nor somatostatin changes the ability of AC toxin to generate cAMP (up to 2 h). Low concentrations of AC toxin amplified the secretory response to hypophysiotrophic hormones. The authors conclude that bacterial AC toxin can rapidly elevate cAMP levels in anterior pituitary cells and that it is the response that explains the subsequent acceleration of hormone release

An α4β1 integrin antagonist decreases airway inflammation in ovalbumin-exposed mice

Science.gov (United States)

Kenyon, Nicholas J.; Liu, Ruiwu; O’Roark, Erin M.; Huang, Wenzhe; Peng, Li; Lam, Kit S.

2008-01-01

Inhibition of the α4 subunit of both the α4β1 and α4β7 integrins has shown promise in decreasing airway inflammation and airway hyperresponsiveness in various animal models. We hypothesized that a novel, high-affinity α4β1 antagonist (LLP2A) would decrease the migration of eosinophils to the lung and ameliorate the airway hyperresponsiveness in a mouse model of ovalbumin-induced airway inflammation. To test this hypothesis, we administered LLP2A, or scrambled LLP2A (a negative control), prior to exposure of sensitized BALB/c mice to ovalbumin aerosol. We can partially prevent, or reverse, the airway inflammatory response, but not airways hyperresponsiveness, by treatment of mice with LLP2A, a synthetic peptidomimetic α4β1 antagonist LLP2A. Specifically engineered, PEGylated (PEG) formulations of this antagonist further reduce the airway inflammatory response to ovalbumin lbumin, presumably by improving the circulating half-life of the drug. PMID:19103195

Engineering the Substrate Specificity of the DhbE Adenylation Domain by Yeast Cell Surface Display

OpenAIRE

Zhang, Keya; Nelson, Kathryn M.; Bhuripanyo, Karan; Grimes, Kimberly D.; Zhao, Bo; Aldrich, Courtney C.; Yin, Jun

2013-01-01

The adenylation (A) domains of nonribosomal peptide synthetases (NRPSs) activate aryl acids or amino acids to launch their transfer through the NRPS assembly line for the biosynthesis of many medicinally important natural products. In order to expand the substrate pool of NRPSs, we developed a method based on yeast cell surface display to engineer the substrate specificities of the A-domains. We acquired A-domain mutants of DhbE that have 11- and 6-fold increases in kcat/Km with nonnative sub...

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

Directory of Open Access Journals (Sweden)

João Paulo Victorino Santos

2013-10-01

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.

Radiation inactivation of multimeric enzymes: application to subunit interactions of adenylate cyclase

International Nuclear Information System (INIS)

Verkman, A.S.; Skorecki, K.L.; Ausiello, D.A.

1986-01-01

Radiation inactivation has been applied extensively to determine the molecular weight of soluble enzyme and receptor systems from the slope of a linear ln (activity) vs. dose curve. Complex nonlinear inactivation curves are predicted for multimeric enzyme systems, composed of distinct subunits in equilibrium with multimeric complexes. For the system A1 + A2----A1A2, with an active A1A2 complex (associative model), the ln (activity) vs. dose curve is linear for high dissociation constant, K. If a monomer, A1, has all the enzyme activity (dissociative model), the ln (activity) vs. dose curve has an activation hump at low radiation dose if the inactive subunit, A2, has a higher molecular weight than A1 and has upward concavity when A2 is smaller than A1. In general, a radiation inactivation model for a multistep mechanism for enzyme activation fulfills the characteristics of an associative or dissociative model if the reaction step forming active enzyme is an associative or dissociative reaction. Target theory gives the molecular weight of the active enzyme subunit or complex from the limiting slope of the ln (activity) vs. dose curve at high radiation dose. If energy transfer occurs among subunits in the multimer, the ln (activity) vs. dose curve is linear for a single active component and is concave upward for two or more active components. The use of radiation inactivation as a method to determine enzyme size and multimeric subunit assembly is discussed with specific application to the hormone-sensitive adenylate cyclase system. It is shown that the complex inactivation curves presented in the accompanying paper can be used select the best mechanism out of a series of seven proposed mechanisms for the activation of adenylate cyclase by hormone

Nonpeptidic urotensin-II receptor antagonists I: in vitro pharmacological characterization of SB-706375

Science.gov (United States)

Douglas, Stephen A; Behm, David J; Aiyar, Nambi V; Naselsky, Diane; Disa, Jyoti; Brooks, David P; Ohlstein, Eliot H; Gleason, John G; Sarau, Henry M; Foley, James J; Buckley, Peter T; Schmidt, Dulcie B; Wixted, William E; Widdowson, Katherine; Riley, Graham; Jin, Jian; Gallagher, Timothy F; Schmidt, Stanley J; Ridgers, Lance; Christmann, Lisa T; Keenan, Richard M; Knight, Steven D; Dhanak, Dashyant

2005-01-01

SB-706375 potently inhibited [125I]hU-II binding to both mammalian recombinant and ‘native' UT receptors (Ki 4.7±1.5 to 20.7±3.6 nM at rodent, feline and primate recombinant UT receptors and Ki 5.4±0.4 nM at the endogenous UT receptor in SJRH30 cells). Prior exposure to SB-706375 (1 μM, 30 min) did not alter [125I]hU-II binding affinity or density in recombinant cells (KD 3.1±0.4 vs 5.8±0.9 nM and Bmax 3.1±1.0 vs 2.8±0.8 pmol mg−1) consistent with a reversible mode of action. The novel, nonpeptidic radioligand [3H]SB-657510, a close analogue of SB-706375, bound to the monkey UT receptor (KD 2.6±0.4 nM, Bmax 0.86±0.12 pmol mg−1) in a manner that was inhibited by both U-II isopeptides and SB-706375 (Ki 4.6±1.4 to 17.6±5.4 nM) consistent with the sulphonamides and native U-II ligands sharing a common UT receptor binding domain. SB-706375 was a potent, competitive hU-II antagonist across species with pKb 7.29–8.00 in HEK293-UT receptor cells (inhibition of [Ca2+]i-mobilization) and pKb 7.47 in rat isolated aorta (inhibition of contraction). SB-706375 also reversed tone established in the rat aorta by prior exposure to hU-II (Kapp∼20 nM). SB-706375 was a selective U-II antagonist with ⩾100-fold selectivity for the human UT receptor compared to 86 distinct receptors, ion channels, enzymes, transporters and nuclear hormones (Ki/IC50>1 μM). Accordingly, the contractile responses induced in isolated aortae by KCl, phenylephrine, angiotensin II and endothelin-1 were unaltered by SB-706375 (1 μM). In summary, SB-706375 is a high-affinity, surmountable, reversible and selective nonpeptide UT receptor antagonist with cross-species activity that will assist in delineating the pathophysiological actions of U-II in mammals. PMID:15852036

Isolation and characterization of a novel analyte from Bacillus subtilis SC-8 antagonistic to Bacillus cereus.

Science.gov (United States)

Lee, Nam Keun; Yeo, In-Cheol; Park, Joung Whan; Kang, Byung-Sun; Hahm, Young Tae

2010-09-01

In this study, an effective substance was isolated from Bacillus subtilis SC-8, which was obtained from traditionally fermented soybean paste, cheonggukjang. The substance was purified by HPLC, and its properties were analyzed. It had an adequate antagonistic effect on Bacilluscereus, and its spectrum of activity was narrow. When tested on several gram-negative and gram-positive foodborne pathogenic bacteria such as Salmonella enterica, Salmonella enteritidis, Staphylococcus aureus, and Listeria monocytogenes, no antagonistic effect was observed. Applying the derivative from B. subtilis SC-8 within the same genus did not inhibit the growth of major soybean-fermenting bacteria such as Bacillus subtilis, Bacillus licheniformis, and Bacillus amyloquefaciens. The range of pH stability of the purified antagonistic substance was wide (from 4.0 to >10.0), and the substance was thermally stable up to 60 degrees C. In the various enzyme treatments, the antagonistic activity of the purified substance was reduced with proteinase K, protease, and lipase; its activity was partially destroyed with esterase. Spores of B. cereus did not grow at all in the presence of 5mug/mL of the purified antagonistic substance. The isolated antagonistic substance was thought to be an antibiotic-like lipopeptidal compound and was tentatively named BSAP-254 because it absorbed to UV radiation at 254nm. Copyright 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-03-15

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

The effect of propofol on CA1 pyramidal cell excitability and GABAA-mediated inhibition in the rat hippocampal slice.

Science.gov (United States)

Albertson, T E; Walby, W F; Stark, L G; Joy, R M

1996-05-24

An in vitro paired-pulse orthodromic stimulation technique was used to examine the effects of propofol on excitatory afferent terminals, CA1 pyramidal cells and recurrent collateral evoked inhibition in the rat hippocampal slice. Hippocampal slices 400 microns thick were perfused with oxygenated artificial cerebrospinal fluid, and electrodes were placed in the CA1 region to record extracellular field population spike (PS) or excitatory postsynaptic potential (EPSP) responses to stimulation of Schaffer collateral/commissural fibers. Gamma-aminobutyric acid (GABA)-mediated recurrent inhibition was measured using a paired-pulse technique. The major effect of propofol (7-28 microM) was a dose and time dependent increase in the intensity and duration of GABA-mediated inhibition. This propofol effect could be rapidly and completely reversed by exposure to known GABAA antagonists, including picrotoxin, bicuculline and pentylenetetrazol. It was also reversed by the chloride channel antagonist, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). It was not antagonized by central (flumazenil) or peripheral (PK11195) benzodiazepine antagonists. Reversal of endogenous inhibition was also noted with the antagonists picrotoxin and pentylenetetrazol. Input/output curves constructed using stimulus propofol caused only a small enhancement of EPSPs at higher stimulus intensities but had no effect on PS amplitudes. These studies are consistent with propofol having a GABAA-chloride channel mechanism causing its effect on recurrent collateral evoked inhibition in the rat hippocampal slice.

Effect of different forms of adenylate cyclase toxin of Bordetella pertussis on protection afforded by an acellular pertussis vaccine in a murine model.

Science.gov (United States)

Cheung, Gordon Y C; Xing, Dorothy; Prior, Sandra; Corbel, Michael J; Parton, Roger; Coote, John G

2006-12-01

Four recombinant forms of the cell-invasive adenylate cyclase toxin (CyaA) of Bordetella pertussis were compared for the ability to enhance protection against B. pertussis in mice when coadministered with an acellular pertussis vaccine (ACV). The four forms were as follows: fully functional CyaA, a CyaA form lacking adenylate cyclase enzymatic activity (CyaA*), and the nonacylated forms of these toxins, i.e., proCyaA and proCyaA*, respectively. None of these forms alone conferred significant (P > 0.05) protection against B. pertussis in a murine intranasal challenge model. Mice immunized with ACV alone showed significant (P protection was only significant (P protection provided by CyaA* was due to an augmentation of both Th1 and Th2 immune responses to B. pertussis antigens.

New trends in combined use of gonadotropin-releasing hormone antagonists with gonadotropins or pulsatile gonadotropin-releasing hormone in ovulation induction and assisted reproductive technologies.

Science.gov (United States)

Gordon, K; Danforth, D R; Williams, R F; Hodgen, G D

1992-10-01

The use of gonadotropin-releasing hormone agonists as adjunctive therapy with gonadotropins for ovulation induction in in vitro fertilization and other assisted reproductive technologies has become common clinical practice. With the recent advent of potent gonadotropin-releasing hormone antagonists free from the marked histamine-release effects that stymied earlier compounds, an attractive alternative method may be available. We have established the feasibility of combining gonadotropin-releasing hormone antagonist-induced inhibition of endogenous gonadotropins with exogenous gonadotropin therapy for ovulation induction in a nonhuman primate model. Here, the principal benefits to be gained from using the gonadotropin-releasing hormone antagonist rather than the gonadotropin-releasing hormone agonist are the immediate inhibition of pituitary gonadotropin secretion without the "flare effect," which brings greater safety and convenience for patients and the medical team and saves time and money. We have also recently demonstrated the feasibility of combining gonadotropin-releasing hormone antagonist with pulsatile gonadotropin-releasing hormone therapy for the controlled restoration of gonadotropin secretion and gonadal steroidogenesis culminating in apparently normal (singleton) ovulatory cycles. This is feasible only with gonadotropin-releasing hormone antagonists because, unlike gonadotropin-releasing hormone agonists, they achieve control of the pituitary-ovarian axis without down regulation of the gonadotropin-releasing hormone receptor system. This capacity to override gonadotropin-releasing hormone antagonist-induced suppression of pituitary-ovarian function may allow new treatment modalities to be employed for women who suffer from chronic hyperandrogenemia with polycystic ovarian disease.

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.

1999-01-01

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

Antagonistic activity of dairy lactobacilli against gram-foodborne pathogens - doi: 10.4025/actascitechnol.v36i1.18776

Directory of Open Access Journals (Sweden)

Marco Geria

2014-01-01

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.

Evodiamine as a novel antagonist of aryl hydrocarbon receptor

International Nuclear Information System (INIS)

Yu, Hui; Tu, Yongjiu; Zhang, Chun; Fan, Xia; Wang, Xi; Wang, Zhanli; Liang, Huaping

2010-01-01

Research highlights: → Evodiamine interacted with the AhR. → Evodiamine inhibited the specific binding of [ 3 H]-TCDD to the AhR. → 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 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.

Pituitary adenylate cyclase-activating polypeptide: occurrence and relaxant effect in female genital tract

DEFF Research Database (Denmark)

Steenstrup, B R; Alm, P; Hannibal, J

1995-01-01

The distribution, localization, and smooth muscle effects of pituitary adenylate cyclase-activating polypeptide (PACAP) were studied in the human female genital tract. The concentrations of PACAP-38 and PACAP-27 were measured by radioimmunoassays, and both peptides were found throughout the genital...... was observed. The findings suggest a smooth muscle regulatory role of PACAP in the human female reproductive tract....... tract. The highest concentrations of PACAP-38 were detected in the ovary, the upper part of vagina, and the perineum. The concentrations of PACAP-27 were generally low, in some regions below the detection limit and in other regions 1 to 5% of the PACAP-38 concentrations. Immunocytochemistry revealed...

Antipathy of Trichoderma against Sclerotium rolfsii Sacc.: Evaluation of Cell Wall-Degrading Enzymatic Activities and Molecular Diversity Analysis of Antagonists.

Science.gov (United States)

Hirpara, Darshna G; Gajera, Harsukh P; Hirpara, Hitesh Z; Golakiya, Balubhai A

2017-01-01

The fungus Trichoderma is a teleomorph of the Hypocrea genus and associated with biological control of plant diseases. The microscopic, biochemical, and molecular characterization of Trichoderma was carried out and evaluated for in vitro antagonistic activity against the fungal pathogen Sclerotium rolfsii causing stem rot disease in groundnut. In total, 11 isolates of Trichoderma were examined for antagonism at 6 and 12 days after inoculation (DAI). Out of 11, T. virens NBAII Tvs12 evidenced the highest (87.91%) growth inhibition of the test pathogen followed by T. koningii MTCC 796 (67.03%), T. viride NBAII Tv23 (63.74%), and T. harzianum NBAII Th1 (60.44%). Strong mycoparasitism was observed in the best antagonist Tvs12 strain during 6-12 DAI. The specific activity of cell wall-degrading enzymes - chitinase and β-1,3-glucanase - was positively correlated with growth inhibition of the test pathogen. In total, 18 simple sequence repeat (SSR) polymorphisms were reported to amplify 202 alleles across 11 Trichoderma isolates. The average polymorphism information content for SSR markers was found to be 0.80. The best antagonist Tvs 12 was identified with 7 unique SSR alleles amplified by 5 SSR markers. Clustering patterns of 11 Trichoderma strains showed the best antagonist T. virens NBAII Tvs 12 outgrouped with a minimum 3% similarity from the rest of Trichoderma. © 2017 S. Karger AG, Basel.

XIAP antagonist embelin inhibited proliferation of cholangiocarcinoma cells.

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Cody J Wehrkamp

Full Text Available Cholangiocarcinoma cells are dependent on antiapoptotic signaling for survival and resistance to death stimuli. Recent mechanistic studies have revealed that increased cellular expression of the E3 ubiquitin-protein ligase X-linked inhibitor of apoptosis (XIAP impairs TRAIL- and chemotherapy-induced cytotoxicity, promoting survival of cholangiocarcinoma cells. This study was undertaken to determine if pharmacologic antagonism of XIAP protein was sufficient to sensitize cholangiocarcinoma cells to cell death. We employed malignant cholangiocarcinoma cell lines and used embelin to antagonize XIAP protein. Embelin treatment resulted in decreased XIAP protein levels by 8 hours of treatment with maximal effect at 16 hours in KMCH and Mz-ChA-1 cells. Assessment of nuclear morphology demonstrated a concentration-dependent increase in nuclear staining. Interestingly, embelin induced nuclear morphology changes as a single agent, independent of the addition of TNF-related apoptosis inducing ligand (TRAIL. However, caspase activity assays revealed that increasing embelin concentrations resulted in slight inhibition of caspase activity, not activation. In addition, the use of a pan-caspase inhibitor did not prevent nuclear morphology changes. Finally, embelin treatment of cholangiocarcinoma cells did not induce DNA fragmentation or PARP cleavage. Apoptosis does not appear to contribute to the effects of embelin on cholangiocarcinoma cells. Instead, embelin caused inhibition of cell proliferation and cell cycle analysis indicated that embelin increased the number of cells in S and G2/M phase. Our results demonstrate that embelin decreased proliferation in cholangiocarcinoma cell lines. Embelin treatment resulted in decreased XIAP protein expression, but did not induce or enhance apoptosis. Thus, in cholangiocarcinoma cells the mechanism of action of embelin may not be dependent on apoptosis.

Facilitation of soleus but not tibialis anterior motor evoked potentials before onset of antagonist contraction

DEFF Research Database (Denmark)

Geertsen, Svend Sparre; Zuur, Abraham Theodore; Nielsen, Jens Bo

2008-01-01

Objective: It is well documented that corticospinal projections to motoneurons of one muscle inhibit antagonist motoneurons through collaterals to reciprocally organized spinal inhibitory interneurons. During and just prior to dorsiflexion of the ankle, soleus motoneurons are thus inhibited...... the MEP is evoked. Methods: Seated subjects (n=11) were instructed to react to an auditory cue by contracting either the tibialis anterior (TA) or soleus muscle of the left ankle to 30% of their maximal dorsiflexion voluntary contraction (MVC) or plantar flexion MVC, respectively. Focal TMS at 1.2 x motor...

Bisamidate Prodrugs of 2-Substituted 9-[2-(Phosphonomethoxy)ethyl]adenine (PMEA, adefovir) as Selective Inhibitors of Adenylate Cyclase Toxin from Bordetella pertussis

Czech Academy of Sciences Publication Activity Database

Česnek, Michal; Jansa, Petr; Šmídková, Markéta; Mertlíková-Kaiserová, Helena; Dračínský, Martin; Brust, T. F.; Pávek, P.; Trejtnar, F.; Watts, V. J.; Janeba, Zlatko

2015-01-01

Roč. 10, č. 8 (2015), s. 1351-1364 ISSN 1860-7179 R&D Projects: GA MV VG20102015046 Institutional support: RVO:61388963 Keywords : adenylate cyclase toxin * bisamidates * Bordetella pertussis * nucleosides * phosphonates Subject RIV: CC - Organic Chemistry Impact factor: 2.980, year: 2015

Effects of casoxin 4 on morphine inhibition of small animal intestinal contractility and gut transit in the mouse

Directory of Open Access Journals (Sweden)

Glen S Patten

2011-02-01

Full Text Available Glen S Patten1,2, Richard J Head1, Mahinda Y Abeywardena1,21CSIRO Preventative Health National Research Flagship, Adelaide, Australia; 2CSIRO Food and Nutritional Sciences, Adelaide, AustraliaBackground and aims: Chronic opioid analgesia has the debilitating side-effect of constipation in human patients. The major aims of this study were to: 1 characterize the opioid-specific antagonism of morphine-induced inhibition of electrically driven contraction of the small intestine of mice, rats, and guinea pigs; and 2 test if the oral delivery of small milk-derived opioid antagonist peptides could block morphine-induced inhibition of intestinal transit in mice.Methods: Mouse, rat, and guinea pig intact ileal sections were electrically stimulated to contract and inhibited with morphine in vitro. Morphine inhibition was then blocked by opioid subtype antagonists in the mouse and guinea pig. Using a polymeric dye, Poly R-478, the opioid antagonists casoxin 4 and lactoferroxin A were tested orally for blocking activity of morphine inhibition of gut transit in vivo by single or double gavage techniques.Results: The guinea pig tissue was more sensitive to morphine inhibition compared with the mouse or the rat (IC50 [half maximal inhibitory concentration] values as nmol/L ± SEM were 34 ± 3, 230 ± 13, and 310 ± 14 respectively (P < 0.01. The inhibitory influence of opioid agonists (IC50 in electrically driven ileal mouse preparations were DADLE ([D-Ala2, D-Leu5]-enkephalin ≥ met-enkephalin ≥ dynorphin A ≥ DAMGO ([D-Ala2, N-Me-Phe4, Gly-ol5]-enkephalin > morphine > morphiceptin as nmol/L 13.9, 17.3, 19.5, 23.3, 230, and 403 respectively. The mouse demonstrated predominantly Κ- and δ-opioid receptor activity with a smaller µ-opioid receptor component. Both mouse and guinea pig tissue were sensitive to casoxin 4 antagonism of morphine inhibition of contraction. In contrast to naloxone, relatively high oral doses of the µ-opioid receptor antagonists

Mifepristone inhibits extracellular matrix formation in uterine leiomyoma.

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Patel, Amrita; Malik, Minnie; Britten, Joy; Cox, Jeris; Catherino, William H

2016-04-01

To characterize the efficacy of mifepristone treatment on extracellular matrix (ECM) production in leiomyomas. Laboratory study. University research laboratory. None. Treatment of human immortalized two-dimensional (2D) and three-dimensional (3D) leiomyoma and myometrial cells with mifepristone and the progestin promegestone (R5020). Expression of COL1A1, fibronectin, versican variant V0, and dermatopontin in treated leiomyoma cells by Western blot analysis and confirmatory immunohistochemistry staining of treated 3D cultures. Treatment with progestin stimulated production of COL1A1, fibronectin, versican, and dermatopontin. Mifepristone treatment inhibited protein production of these genes, most notably with versican expression. Combination treatment with both the agonist and antagonist further inhibited protein expression of these genes. Immunohistochemistry performed on 3D cultures demonstrated generalized inhibition of ECM protein concentration. Our study demonstrated that the progesterone agonist R5020 directly stimulated extracellular matrix components COL1A1, fibronectin, versican, and dermatopontin production in human leiomyoma cells. Progesterone antagonist mifepristone decreased protein production of these genes to levels comparable with untreated leiomyoma cells. Published by Elsevier Inc.

Transmitters and pathways mediating inhibition of spinal itch-signaling neurons by scratching and other counterstimuli.

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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.

AM-37 and ST-36 Are Small Molecule Bombesin Receptor Antagonists.

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Moody, Terry W; Tashakkori, Nicole; Mantey, Samuel A; Moreno, Paola; Ramos-Alvarez, Irene; Leopoldo, Marcello; Jensen, Robert T

2017-01-01

While peptide antagonists for the gastrin-releasing peptide receptor (BB 2 R), neuromedin B receptor (BB 1 R), and bombesin (BB) receptor subtype-3 (BRS-3) exist, there is a need to develop non-peptide small molecule inhibitors for all three BBR. The BB agonist (BA)1 binds with high affinity to the BB 1 R, BB 2 R, and BRS-3. In this communication, small molecule BBR antagonists were evaluated using human lung cancer cells. AM-37 and ST-36 inhibited binding to human BB 1 R, BB 2 R, and BRS-3 with similar affinity ( K i = 1.4-10.8 µM). AM-13 and AM-14 were approximately an order of magnitude less potent than AM-37 and ST-36. The ability of BA1 to elevate cytosolic Ca 2+ in human lung cancer cells transfected with BB 1 R, BB 2 R, and BRS-3 was antagonized by AM-37 and ST-36. BA1 increased tyrosine phosphorylation of the EGFR and ERK in lung cancer cells, which was blocked by AM-37 and ST-36. AM-37 and ST-36 reduced the growth of lung cancer cells that have BBR. The results indicate that AM-37 and ST-36 function as small molecule BB receptor antagonists.

Differential involvement of dopamine D-1 and D-2 receptors in the circling behaviour induced by apomorphine, SK & F 38393, pergolide and LY 171555 in 6-hydroxydopamine-lesioned rats.

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Arnt, J; Hyttel, J

1985-01-01

The antagonistic effect of dopamine (DA) D-1 and D-2 antagonists against circling behaviour induced by various DA agonists in 6-OHDA-lesioned rats has been investigated. DA D-1/D-2 selectivity of agonists in vitro was measured by the stimulatory effect on DA-sensitive adenylate cyclase in rat striatal homogenates (D-1), the inhibitory effect on electrically-induced release of 3H-DA in rabbit striatal slices (D-2) and the affinity to 3H-piflutixol (D-1) and 3H-spiroperidol (D-2) binding sites in rat striatal membranes. The contralateral circling behaviour induced by the DA D-1 agonist SK & F 38393 was blocked by the DA D-1 antagonist, SCH 23390, and by the mixed DA D-1/D-2 antagonist cis(Z)-flupentixol, but was not influenced by the DA D-2 antagonists spiroperidol and clebopride. In contrast, circling behaviour induced by the preferential DA D-2 agonists pergolide and LY 171555 was blocked by clebopride, spiroperidol, and cis(Z)-flupentixol, but weakly or not influenced by SCH 23390. Apomorphine-induced circling behaviour was blocked by cis(Z)-flupentixol, partially antagonized by SCH 23390 and clebopride but not inhibited by spiroperidol, although the time-course of circling was changed. Combinations of SCH 23390 with spiroperidol or clebopride in low doses completely blocked the effect of apomorphine. These results indicate that DA D-1 and D-2 receptors mediate circling behaviour through separate mechanisms which can be independently manipulated with respective agonists and antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)

Discovery of MK-3697: a selective orexin 2 receptor antagonist (2-SORA) for the treatment of insomnia.

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Roecker, Anthony J; Reger, Thomas S; Mattern, M Christa; Mercer, Swati P; Bergman, Jeffrey M; Schreier, John D; Cube, Rowena V; Cox, Christopher D; Li, Dansu; Lemaire, Wei; Bruno, Joseph G; Harrell, C Meacham; Garson, Susan L; Gotter, Anthony L; Fox, Steven V; Stevens, Joanne; Tannenbaum, Pamela L; Prueksaritanont, Thomayant; Cabalu, Tamara D; Cui, Donghui; Stellabott, Joyce; Hartman, George D; Young, Steven D; Winrow, Christopher J; Renger, John J; Coleman, Paul J

2014-10-15

Orexin receptor antagonists have demonstrated clinical utility for the treatment of insomnia. The majority of clinical efforts to date have focused on the development of dual orexin receptor antagonists (DORAs), small molecules that antagonize both the orexin 1 and orexin 2 receptors. Our group has recently disclosed medicinal chemistry efforts to identify highly potent, orally bioavailable selective orexin 2 receptor antagonists (2-SORAs) that possess acceptable profiles for clinical development. Herein we report additional SAR studies within the 'triaryl' amide 2-SORA series focused on improvements in compound stability in acidic media and time-dependent inhibition of CYP3A4. These studies resulted in the discovery of 2,5-disubstituted isonicotinamide 2-SORAs such as compound 24 that demonstrated improved stability and TDI profiles as well as excellent sleep efficacy across species. Copyright © 2014 Elsevier Ltd. All rights reserved.

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) in the circulation after sumatriptan

DEFF Research Database (Denmark)

Hansen, Jakob Møller; Fahrenkrug, Jan; Petersen, Jesper Troensegaard

2013-01-01

The origin of migraine pain is still elusive, but increasingly researchers focus on the neuropeptides in the perivascular space of cranial vessels as important mediators of nociceptive input during migraine attacks. The parasympathetic neurotransmitters, pituitary adenylate cyclase activating...... peptide-38 (PACAP38) and vasoactive intestinal peptide (VIP) may be released from parasympathetic fibres and activate sensory nerve fibres during migraine attacks. Triptans are effective and well tolerated in acute migraine management but the exact mechanism of action is still debated. Triptans might...

Albumin, in the Presence of Calcium, Elicits a Massive Increase in Extracellular Bordetella Adenylate Cyclase Toxin.

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Gonyar, Laura A; Gray, Mary C; Christianson, Gregory J; Mehrad, Borna; Hewlett, Erik L

2017-06-01

Pertussis (whooping cough), caused by Bordetella pertussis , is resurging in the United States and worldwide. Adenylate cyclase toxin (ACT) is a critical factor in establishing infection with B. pertussis and acts by specifically inhibiting the response of myeloid leukocytes to the pathogen. We report here that serum components, as discovered during growth in fetal bovine serum (FBS), elicit a robust increase in the amount of ACT, and ≥90% of this ACT is localized to the supernatant, unlike growth without FBS, in which ≥90% is associated with the bacterium. We have found that albumin, in the presence of physiological concentrations of calcium, acts specifically to enhance the amount of ACT and its localization to the supernatant. Respiratory secretions, which contain albumin, promote an increase in amount and localization of active ACT that is comparable to that elicited by serum and albumin. The response to albumin is not mediated through regulation of ACT at the transcriptional level or activation of the Bvg two-component system. As further illustration of the specificity of this phenomenon, serum collected from mice that lack albumin does not stimulate an increase in ACT. These data, demonstrating that albumin and calcium act synergistically in the host environment to increase production and release of ACT, strongly suggest that this phenomenon reflects a novel host-pathogen interaction that is central to infection with B. pertussis and other Bordetella species. Copyright © 2017 American Society for Microbiology.

Sepsis Strengthens Antagonistic Actions of Neostigmine on Rocuronium in a Rat Model of Cecal Ligation and Puncture

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Jin Wu

2016-01-01

Conclusions: Sepsis strengthened the antagonistic actions of neostigmine 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.

Antagonistic Activity of Lactobacillus reuteri Strains on the Adhesion Characteristics of Selected Pathogens

OpenAIRE

Singh, Tejinder P.; Kaur, Gurpreet; Kapila, Suman; Malik, Ravinder K.

2017-01-01

Adhesion ability of probiotics is the key factor that decides their colonization in the gastrointestinal tract and potential to inhibit pathogens. Therefore, adhesion ability can be considered as a key determinant for probiotic efficacy. Presents study documents the antagonistic activity of viable/untreated, Lithium chloride (LiCl) treated or heat-killed forms of eight probiotic Lactobacillus reuteri strains on the adhesion characteristics of selected pathogens. All strains investigated were ...

Prolonged inhibition of luteinizing hormone and testosterone levels in male rats with the luteinizing hormone-releasing hormone antagonist SB-75.

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Bokser, L; Bajusz, S; Groot, K; Schally, A V

1990-09-01

Inhibitory effects of the potent antagonist of luteinizing hormone-releasing hormone N-Ac-[3-(2-naphthyl)-D-alanine1,4-chloro-D-phenylalanine2,3- (3-pyridyl)-D- alanine3,D-citrulline6,D-alanine10]luteinizing hormone-releasing hormone (SB-75) free of edematogenic effects were investigated in male rats. In a study to determine the effect on luteinizing hormone levels in castrated male rats, SB-75 was injected s.c. in doses of 0.625, 1.25, 2.5, 5.0, and 10 micrograms. Blood samples were taken at different intervals for 48 hr. All doses of SB-75 significantly decreased luteinizing hormone levels for greater than 6 hr (P less than 0.01); this inhibition lasted for greater than 24 hr (P less than 0.01) with a dose of 5.0 micrograms and greater than 48 hr with 10 micrograms (P less than 0.05). Serum testosterone levels were also measured in intact male rats injected with SB-75 in doses of 25, 50, and 100 micrograms. All doses produced a dramatic fall in testosterone to castration levels 6 hr after injection (P less than 0.01); this inhibition of serum testosterone was maintained for greater than 72 hr, but only the 100-micrograms dose could keep testosterone in the castration range for greater than 24 hr (P less than 0.01). In another study using a specific RIA, we obtained the pharmacokinetic release pattern of SB-75 from two sustained delivery formulations of SB-75 pamoate microgranules and examined their effect on serum testosterone. After a single i.m. injection of 20 mg of one batch of microgranules, a large peak corresponding to SB-75 at 45.8 ng/ml was observed, corresponding to the "burst" effect. Levels of the analog decreased to 19.6 ng/ml on day 2, gradually reached a concentration of 4.7 ng/ml on day 7, and kept declining thereafter. Testosterone levels were reduced on day 1 (P less than 0.01) and were maintained at low values for greater than 7 days (P less than 0.05). In rats injected with 10 mg of SB-75 pamoate microgranules of the second batch, SB-75 serum

Activity of adenylate cyclase in plasma membranes of pulmonary tissue remote times following nonlethal gamma-irradiation of rats

International Nuclear Information System (INIS)

Slozhenkina, L.V.; Ruda, V.P.; Ushakova, T.E.; Kuzin, A.M.

1990-01-01

Basal and stimulated activity of adenylate cyclase (cyclizing ATP-pyrophosphate lyase, E.C. 4.6.1.1., AC) in plasma membranes of pumonary tissye was being studied during a year after fractionated irradiation of rats (2 Gyx3). Basal and hormone-stimulated activity of AC was shown to vary significantly from normal 6 and 12 months after irradiation. The exposed membranes responded differently to AC activation by isoproterenol and F -

5-HT1A receptor antagonists reduce food intake and body weight by reducing total meals with no conditioned taste aversion.

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Dill, M Joelle; Shaw, Janice; Cramer, Jeff; Sindelar, Dana K

2013-11-01

Serotonin acts through receptors controlling several physiological functions, including energy homeostasis regulation and food intake. Recent experiments demonstrated that 5-HT1A receptor antagonists reduce food intake. We sought to examine the microstructure of feeding with 5-HT1A receptor antagonists using a food intake monitoring system. We also examined the relationship between food intake, inhibition of binding and pharmacokinetic (PK) profiles of the antagonists. Ex vivo binding revealed that, at doses used in this study to reduce food intake, inhibition of binding of a 5-HT1A agonist by ~40% was reached in diet-induced obese (DIO) mice with a trend for higher binding in DIO vs. lean animals. Additionally, PK analysis detected levels from 2 to 24h post-compound administration. Male DIO mice were administered 5-HT1A receptor antagonists LY439934 (10 or 30 mg/kg, p.o.), WAY100635 (3 or 10mg/kg, s.c.), SRA-333 (10 or 30 mg/kg, p.o.), or NAD-299 (3 or 10mg/kg, s.c.) for 3 days and meal patterns were measured. Analyses revealed that for each antagonist, 24-h food intake was reduced through a specific decrease in the total number of meals. Compared to controls, meal number was decreased 14-35% in the high dose. Average meal size was not changed by any of the compounds. The reduction in food intake reduced body weight 1-4% compared to Vehicle controls. Subsequently, a conditioned taste aversion (CTA) assay was used to determine whether the feeding decrease might be an indicator of aversion, nausea, or visceral illness caused by the antagonists. Using a two bottle preference test, it was found that none of the compounds produced a CTA. The decrease in food intake does not appear to be a response to nausea or malaise. These results indicate that 5-HT1A receptor antagonist suppresses feeding, specifically by decreasing the number of meals, and induce weight loss without an aversive side effect. © 2013 Elsevier Inc. All rights reserved.

Overproduction, Purification and Characterization of Adenylate Deaminase from Aspergillus oryzae.

Science.gov (United States)

Li, Shubo; Qian, Yi; Liang, Yunlong; Chen, Xinkuan; Zhao, Mouming; Guo, Yuan; Pang, Zongwen

2016-12-01

Adenylate deaminase (AMPD, EC 3.5.4.6) is an aminohydrolase that widely used in the food and medicine industries. In this study, the gene encoding Aspergillus oryzae AMPD was cloned and expressed in Escherichia coli. Induction with 0.75 mM isopropyl β-D-l-thiogalactopyranoside resulted in an enzyme activity of 1773.9 U/mL. Recombinant AMPD was purified to electrophoretic homogeneity using nickel affinity chromatography, and its molecular weight was calculated as 78.6 kDa. Purified AMPD exhibited maximal activity at 35 °C, pH 6.0 and 30 mM K + , with apparent K m and V max values of 2.7 × 10 -4  M and 77.5 μmol/mg/min under these conditions. HPLC revealed that recombinant AMPD could effectively catalyse the synthesis of inosine-5'-monophosphate (IMP) with minimal by-products, indicating high specificity and suggesting that it could prove useful for IMP production.

STC1 interference on calcitonin family of receptors signaling during osteoblastogenesis via adenylate cyclase inhibition.

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Terra, Silvia R; Cardoso, João Carlos R; Félix, Rute C; Martins, Leo Anderson M; Souza, Diogo Onofre G; Guma, Fatima C R; Canário, Adelino Vicente M; Schein, Vanessa

2015-03-05

Stanniocalcin 1 (STC1) and calcitonin gene-related peptide (CGRP) are involved in bone formation/remodeling. Here we investigate the effects of STC1 on functional heterodimer complex CALCRL/RAMP1, expression and activity during osteoblastogenesis. STC1 did not modify CALCRL and ramp1 gene expression during osteoblastogenesis when compared to controls. However, plasma membrane spatial distribution of CALCRL/RAMP1 was modified in 7-day pre-osteoblasts exposed to either CGRP or STC1, and both peptides induced CALCRL and RAMP1 assembly. CGRP, but not STC1 stimulated cAMP accumulation in 7-day osteoblasts and in CALCRL/RAMP1 transfected HEK293 cells. Furthermore, STC1 inhibited forskolin stimulated cAMP accumulation of HEK293 cells, but not in CALCRL/RAMP1 transfected HEK293 cells. However, STC1 inhibited cAMP accumulation in calcitonin receptor (CTR) HEK293 transfected cells stimulated by calcitonin. In conclusion, STC1 signals through inhibitory G-protein modulates CGRP receptor spatial localization during osteoblastogenesis and may function as a regulatory factor interacting with calcitonin peptide members during bone formation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Pharmacological profile of CS-3150, a novel, highly potent and selective non-steroidal mineralocorticoid receptor antagonist.

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Arai, Kiyoshi; Homma, Tsuyoshi; Morikawa, Yuka; Ubukata, Naoko; Tsuruoka, Hiyoyuki; Aoki, Kazumasa; Ishikawa, Hirokazu; Mizuno, Makoto; Sada, Toshio

2015-08-15

The present study was designed to characterize the pharmacological profile of CS-3150, a novel non-steroidal mineralocorticoid receptor antagonist. In the radioligand-binding assay, CS-3150 inhibited (3)H-aldosterone binding to mineralocorticoid receptor with an IC50 value of 9.4nM, and its potency was superior to that of spironolactone and eplerenone, whose IC50s were 36 and 713nM, respectively. CS-3150 also showed at least 1000-fold higher selectivity for mineralocorticoid receptor over other steroid hormone receptors, glucocorticoid receptor, androgen receptor and progesterone receptor. In the reporter gene assay, CS-3150 inhibited aldosterone-induced transcriptional activation of human mineralocorticoid receptor with an IC50 value of 3.7nM, and its potency was superior to that of spironolactone and eplerenone, whose IC50s were 66 and 970nM, respectively. CS-3150 had no agonistic effect on mineralocorticoid receptor and did not show any antagonistic or agonistic effect on glucocorticoid receptor, androgen receptor and progesterone receptor even at the high concentration of 5μM. In adrenalectomized rats, single oral administration of CS-3150 suppressed aldosterone-induced decrease in urinary Na(+)/K(+) ratio, an index of in vivo mineralocorticoid receptor activation, and this suppressive effect was more potent and longer-lasting than that of spironolactone and eplerenone. Chronic treatment with CS-3150 inhibited blood pressure elevation induced by deoxycorticosterone acetate (DOCA)/salt-loading to rats, and this antihypertensive effect was more potent than that of spironolactone and eplerenone. These findings indicate that CS-3150 is a selective and highly potent mineralocorticoid receptor antagonist with long-lasting oral activity. This agent could be useful for the treatment of hypertension, cardiovascular and renal disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

1998-03-01

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.

Molecular basis of the functional heterogeneity of the muscarinic acetylcholine receptor

International Nuclear Information System (INIS)

Numa, S.; Fukuda, K.; Kubo, T.; Maeda, A.; Akiba, I.; Bujo, H.; Nakai, J.; Mishina, M.; Higashida, H.

1988-01-01

The muscarinic acetylcholine receptor (mAChR) mediates a variety of cellular responses, including inhibition of adenylate cyclase, breakdown of phosphoinositides, and modulation of potassium channels, through the action of guanine-nucleotide-binding regulatory proteins (G proteins). The question then arises as to whether multiple mAChR species exist that are responsible for the various biochemical and physiological effects. In fact, pharmacologically distinguishable forms of the mAChR occur in different tissues and have been provisionally classified into M 1 (I), M 2 cardiac (II), and M 2 glandular (III) subtypes on the basis of their difference in apparent affinity for antagonists. Here, the authors have made attempts to understand the molecular basis of the functional heterogeneity of the mAChR, using recombinant DNA technology

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

Science.gov (United States)

Tutton, P J; Barkla, D H

1983-01-01

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

Central inhibition of initiation of swallowing by systemic administration of diazepam and baclofen in anaesthetized rats.

Science.gov (United States)

Tsujimura, Takanori; Sakai, Shogo; Suzuki, Taku; Ujihara, Izumi; Tsuji, Kojun; Magara, Jin; Canning, Brendan J; Inoue, Makoto

2017-05-01

Dysphagia is caused not only by neurological and/or structural damage but also by medication. We hypothesized memantine, dextromethorphan, diazepam, and baclofen, all commonly used drugs with central sites of action, may regulate swallowing function. Swallows were evoked by upper airway (UA)/pharyngeal distension, punctate mechanical stimulation using a von Frey filament, capsaicin or distilled water (DW) applied topically to the vocal folds, and electrical stimulation of a superior laryngeal nerve (SLN) in anesthetized rats and were documented by recording electromyographic activation of the suprahyoid and thyrohyoid muscles and by visualizing laryngeal elevation. The effects of intraperitoneal or topical administration of each drug on swallowing function were studied. Systemic administration of diazepam and baclofen, but not memantine or dextromethorphan, inhibited swallowing evoked by mechanical, chemical, and electrical stimulation. Both benzodiazepines and GABA A receptor antagonists diminished the inhibitory effects of diazepam, whereas a GABA B receptor antagonist diminished the effects of baclofen. Topically applied diazepam or baclofen had no effect on swallowing. These data indicate that diazepam and baclofen act centrally to inhibit swallowing in anesthetized rats. NEW & NOTEWORTHY Systemic administration of diazepam and baclofen, but not memantine or dextromethorphan, inhibited swallowing evoked by mechanical, chemical, and electrical stimulation. Both benzodiazepines and GABA A receptor antagonists diminished the inhibitory effects of diazepam, whereas a GABA B receptor antagonist diminished the effects of baclofen. Topical applied diazepam or baclofen was without effect on swallowing. Diazepam and baclofen act centrally to inhibit swallowing in anesthetized rats. Copyright © 2017 the American Physiological Society.

Modulation of in vivo immunoglobulin production by endogenous histamine and H1R and H2R agonists and antagonists.

Science.gov (United States)

Tripathi, Trivendra; Shahid, Mohammad; Khan, Haris M; Negi, Mahendra Pal Singh; Siddiqui, Mashiatullah; Khan, Rahat A

2010-01-01

The present study was designed to delineate the immunomodulatory role of histamine receptors (H1R and H2R) and their antibody generation in a rabbit model. Six groups containing 18 rabbits each received either vehicle (sterile distilled water, 1 ml/kg x b.i.d), histamine (100 μg/kg x b.i.d.), H1R agonist (HTMT, 10 μg/kg x b.i.d.), H2R agonist (amthamine, 10 μg/kg x b.i.d.), H1R antagonist (pheniramine, 10 mg/kg x b.i.d.) or H2R antagonist (ranitidine, 10 mg/kg x b.i.d.). All animals were subsequently immunized with an intravenous injection of sheep red blood cells (SRBC). Estimations of total serum immunoglobulins (Igs), immunoglobulin M (IgM) and immunoglobulin G (IgG) were performed by ELISA and hemagglutination assay (HA) at days 0 (pre-immunization), 7, 14, 21, 28 and 58 (post-immunization). Both the ELISA and the HA showed similar production of Igs, IgM and IgG but the results were found comparatively more significant by ELISA as opposed to HA. Results showed that histamine could influence a detectable antibody response to SRBC early (i.e., at day 7), which lasted until day 58. Immunomodulatory processes showed suppression of an Ig generation in the H1R-antagonist group with enhancement in the H2R-antagonist group. The H1R-agonist group showed an increased Ig production in comparison to the H2R-agonist group. The IgM production was inhibited in the H1R-antagonist group as compared to the H2R-antagonist group, and it was also suppressed in H1R-agonist group as compared to H2R-agonist group. IgG production was inhibited in the H1R-antagonist group as opposed to the H2R-antagonist group. In contrast, the H1R-agonist group increased IgG production as compared to the H2R-agonist group. All the results were found to be statistically significant (p < 0.05 or p < 0.01). In conclusion, histamine and its receptor (H1R and H2R) agonists enhance antibody production by triggering the histamine receptors (H1R and H2R), and both the H1R antagonist and the H2R antagonist

Antagonistic Bioactivity of Endophytic Actinomycetes Isolated from Medicinal Plants

Directory of Open Access Journals (Sweden)

M. Gangwar

2011-10-01

Full Text Available Endophytic actinomycetes are promising biocontrol agents for use in agriculture and have been isolated from various plant species. In the present study, 40 endophytic actinomycetes were isolated from roots, stems and leaves of three medicinal plants viz. Aloe vera, Mentha arvensis and Ocimum sanctum. The identification revealed that the majority of the isolates were Streptomyces spp. and the rest were identified as Saccharopolyspora spp., Micromonospora spp. and Actinopolyspora spp. The dual tests revealed that nine endophytic actinomycete isolates displayed a wide spectrum activity against nine fungal phytopathogens. Out of 8 isolates, 90% inhibited the growth of at least one or more phytopathogenic fungi and Saccharopolyspora 0-9 (Out of 8 isolates, 90% inhibited the growth of at least one or more phytopathogenic fungi and Saccharopolyspora 0-9 exhibited antagonistic activity against Aspergillus niger, Aspergillus flavus, Alternaria brassicicola, Botrytis cinerea, Penicillium digitatum, Fusarium oxysporum, Penicillium pinophilum, Phytophthora dresclea and Colletotrichum falcatum.

The IL-6 receptor super-antagonist Sant7 enhances antiproliferative and apoptotic effects induced by dexamethasone and zoledronic acid on multiple myeloma cells.

Science.gov (United States)

Tassone, Pierfrancesco; Galea, Eulalia; Forciniti, Samantha; Tagliaferri, Pierosandro; Venuta, Salvatore

2002-10-01

Interleukin-6 (IL-6) is the major growth and survival factor for multiple myeloma (MM), and has been shown to protect MM cells from apoptosis induced by a variety of agents. IL-6 receptor antagonists, which prevent the assembly of functional IL-6 receptor complexes, inhibit cell proliferation and induce apoptosis in MM cells. We have investigated whether the IL-6 receptor super-antagonist Sant7 might enhance the antiproliferative and apoptotic effects induced by the combination of dexamethasone (Dex) and zoledronic acid (Zln) on human MM cell lines and primary cells from MM patients. Here we show that each of these compounds individually induced detectable antiproliferative effects on MM cells. Sant7 significantly enhanced growth inhibition and apoptosis induced by Dex and Zln on both MM cell lines and primary MM cells. These results indicate that overcoming IL-6 mediated cell resistance by Sant7 potentiates the effect of glucocorticoides and bisphosphonates on MM cell growth and survival, providing a rationale for therapies including IL-6 antagonists in MM.

The GABAA Antagonist DPP-4-PIOL Selectively Antagonises Tonic over Phasic GABAergic Currents in Dentate Gyrus Granule Cells

DEFF Research Database (Denmark)

Boddum, Kim; Frølund, Bente; Kristiansen, Uffe

2014-01-01

that phasic and tonic GABAA receptor currents can be selectively inhibited by the antagonists SR 95531 and the 4-PIOL derivative, 4-(3,3-diphenylpropyl)-5-(4-piperidyl)-3-isoxazolol hydrobromide (DPP-4-PIOL), respectively. In dentate gyrus granule cells, SR 95531 was found approximately 4 times as potent...

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

2010-01-01

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...... 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 Erb....... 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...

Frequent epigenetic inactivation of Wnt antagonist genes in breast cancer

Science.gov (United States)

Suzuki, H; Toyota, M; Caraway, H; Gabrielson, E; Ohmura, T; Fujikane, T; Nishikawa, N; Sogabe, Y; Nojima, M; Sonoda, T; Mori, M; Hirata, K; Imai, K; Shinomura, Y; Baylin, S B; Tokino, T

2008-01-01

Although mutation of APC or CTNNB1 (β-catenin) is rare in breast cancer, activation of Wnt signalling is nonetheless thought to play an important role in breast tumorigenesis, and epigenetic silencing of Wnt antagonist genes, including the secreted frizzled-related protein (SFRP) and Dickkopf (DKK) families, has been observed in various tumours. In breast cancer, frequent methylation and silencing of SFRP1 was recently documented; however, altered expression of other Wnt antagonist genes is largely unknown. In the present study, we found frequent methylation of SFRP family genes in breast cancer cell lines (SFRP1, 7 out of 11, 64%; SFRP2, 11 out of 11, 100%; SFRP5, 10 out of 11, 91%) and primary breast tumours (SFRP1, 31 out of 78, 40%; SFRP2, 60 out of 78, 77%; SFRP5, 55 out of 78, 71%). We also observed methylation of DKK1, although less frequently, in cell lines (3 out of 11, 27%) and primary tumours (15 out of 78, 19%). Breast cancer cell lines express various Wnt ligands, and overexpression of SFRPs inhibited cancer cell growth. In addition, overexpression of a β-catenin mutant and depletion of SFRP1 using small interfering RNA synergistically upregulated transcriptional activity of T-cell factor/lymphocyte enhancer factor. Our results confirm the frequent methylation and silencing of Wnt antagonist genes in breast cancer, and suggest that their loss of function contributes to activation of Wnt signalling in breast carcinogenesis. PMID:18283316

AM-37 and ST-36 Are Small Molecule Bombesin Receptor Antagonists

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Terry W. Moody

2017-07-01

Full Text Available While peptide antagonists for the gastrin-releasing peptide receptor (BB2R, neuromedin B receptor (BB1R, and bombesin (BB receptor subtype-3 (BRS-3 exist, there is a need to develop non-peptide small molecule inhibitors for all three BBR. The BB agonist (BA1 binds with high affinity to the BB1R, BB2R, and BRS-3. In this communication, small molecule BBR antagonists were evaluated using human lung cancer cells. AM-37 and ST-36 inhibited binding to human BB1R, BB2R, and BRS-3 with similar affinity (Ki = 1.4–10.8 µM. AM-13 and AM-14 were approximately an order of magnitude less potent than AM-37 and ST-36. The ability of BA1 to elevate cytosolic Ca2+ in human lung cancer cells transfected with BB1R, BB2R, and BRS-3 was antagonized by AM-37 and ST-36. BA1 increased tyrosine phosphorylation of the EGFR and ERK in lung cancer cells, which was blocked by AM-37 and ST-36. AM-37 and ST-36 reduced the growth of lung cancer cells that have BBR. The results indicate that AM-37 and ST-36 function as small molecule BB receptor antagonists.

AM-37 and ST-36 Are Small Molecule Bombesin Receptor Antagonists

Science.gov (United States)

Moody, Terry W.; Tashakkori, Nicole; Mantey, Samuel A.; Moreno, Paola; Ramos-Alvarez, Irene; Leopoldo, Marcello; Jensen, Robert T.

2017-01-01

While peptide antagonists for the gastrin-releasing peptide receptor (BB2R), neuromedin B receptor (BB1R), and bombesin (BB) receptor subtype-3 (BRS-3) exist, there is a need to develop non-peptide small molecule inhibitors for all three BBR. The BB agonist (BA)1 binds with high affinity to the BB1R, BB2R, and BRS-3. In this communication, small molecule BBR antagonists were evaluated using human lung cancer cells. AM-37 and ST-36 inhibited binding to human BB1R, BB2R, and BRS-3 with similar affinity (Ki = 1.4–10.8 µM). AM-13 and AM-14 were approximately an order of magnitude less potent than AM-37 and ST-36. The ability of BA1 to elevate cytosolic Ca2+ in human lung cancer cells transfected with BB1R, BB2R, and BRS-3 was antagonized by AM-37 and ST-36. BA1 increased tyrosine phosphorylation of the EGFR and ERK in lung cancer cells, which was blocked by AM-37 and ST-36. AM-37 and ST-36 reduced the growth of lung cancer cells that have BBR. The results indicate that AM-37 and ST-36 function as small molecule BB receptor antagonists. PMID:28785244

Bovine pancreatic polypeptide as an antagonist of muscarinic cholinergic receptors

International Nuclear Information System (INIS)

Pan, G.Z.; Lu, L.; Qian, J.; Xue, B.G.

1987-01-01

In dispersed acini from rat pancreas, it was found that bovine pancreatic polypeptide (BPP) and its C-fragment hexapeptide amide (PP-6), at concentrations of 0.1 and 30 μM, respectively, could significantly inhibit amylase secretion stimulated by carbachol, and this inhibition by BPP was dose dependent. 45 Ca outflux induced by carbachol was also inhibited by BPP or PP-6, but they had no effect on cholecystokinin octapeptide- (CCK-8) or A23187-stimulated 45 Ca outflux. BPP was also capable of displacing the specific binding of [ 3 H]-quinuclidinyl benzilate to its receptors, and it possessed a higher affinity (K/sub i/35nM) than carbachol (K/sub i/ 1.8 μM) in binding with M-receptors. It is concluded from this study that BPP acts as an antagonist of muscarinic cholinergic receptors in rat pancreatic acini. In addition, BPP inhibited the potentiation of amylase secretion caused by the combination of carbachol plus secretin or vasoactive intestinal peptide. This may be a possible explanation of the inhibitory effect of BPP on secretin-induced pancreatic enzyme secretion shown in vivo, since pancreatic enzyme secretion stimulated by secretin under experimental conditions may be the result of potentiation of enzyme release produced by the peptide in combination with a cholinergic stimulant

A review of granisetron, 5-hydroxytryptamine3 receptor antagonists, and other antiemetics.

Science.gov (United States)

Hsu, Eric S

2010-01-01

Nausea and vomiting are 2 of the most upsetting adverse reactions of chemotherapy. Current guidelines propose 5-hydroxytryptamine3 (5-HT3) receptor antagonists as a pharmacologic intervention for acute and delayed nausea and vomiting [chemotherapy-induced nausea and vomiting (CINV)] associated with moderately and highly emetogenic chemotherapy. Meanwhile, both postoperative nausea and vomiting (PONV) and postdischarge nausea and vomiting are challenging situations after surgeries and procedures. Prophylactic and therapeutic combinations of antiemetics are recommended in patients at high risk of suffering from PONV and postdischarge nausea and vomiting. Granisetron (Kytril) is a selective 5-HT3 receptor antagonist that does not induce or inhibit the hepatic cytochrome P-450 system in vitro. There are also 4 other antagonists of 5-HT3 receptor (dolasetron, ondansetron, palonosetron, and tropisetron) being metabolized via the CYP2D6 and are subject to potential genetic polymorphism. The launch of a new class of antiemetics, the substance P/neurokinin1 receptor antagonists, was attributed to the scientific update on the central generator responsible for emesis and role of substance P. There has been mounting interest in exploring integrative medicine, either acupuncture or acustimulation of P6 (Nei-Kuwan), to complement the western medicine for prevention and management of nausea and vomiting. The potential application of cannabinoids, either alone or in combination with other agents of different mechanism, could contribute further to improve outcome in CINV. Implementation of future treatment guidelines for more effective management of CINV and PONV could certainly improve the efficacy and outcome of cancer and postoperative care.

Effect of cardiopulmonary bypass on beta adrenergic receptor-adenylate cyclase system on surfaces of peripheral lymphocytes.

Science.gov (United States)

Luo, A; Tian, Y; Jin, S

2000-01-01

The experimental results showed that the level of CAMP, the ratio of cAPM to cGMP, IL-2R expression and IL-2 production in vitro in lymphocytes immediate and 2 weeks after cardiopulmonary bypass (CPB) were significantly lower than those before anesthetics in the patients undergoing cardiac surgery with CPB. These findings suggested that CPB could cause serious damage to adrenergic beta receptor-adenylate cyclase system on circulating lymphocytes surfaces, which might be one of the mechanisms resulting in immunosuppression after open heart surgery with CPB.

Filamentous fungi isolated from grape marc as antagonists of Botrytis cinerea

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Jovičić-Petrović Jelena P.

2016-01-01

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

Inhibition of human prostate cancer cells proliferation by a selective alpha1-adrenoceptor antagonist labedipinedilol-A involves cell cycle arrest and apoptosis

International Nuclear Information System (INIS)

Liou, S.-F.; Lin, H.-H.; Liang, J.-C.; Chen, I.-J.; Yeh, J.-L.

2009-01-01

In this research, we conducted an in vitro analysis to evaluate the prostate cancer cells response to labedipinedilol-A in order to determine the effect of this selective α 1 -adrenoceptor antagonist to suppress prostate cancer cell growth by affecting cell proliferation and apoptosis. Here, we report that treatment of androgen-sensitive (LNCaP) and androgen-insensitive (PC-3) prostate cancer cells with labedipinedilol-A inhibited cell proliferation in concentration-dependent and time-dependent manners. Moreover, norepinephrine-stimulated proliferation of both cell lines are markedly inhibited by labedipinedilol-A. The probable involvement of α 1 -adrenoceptors in this cellular response is suggested. Labedipinedilol-A-induced growth inhibition was associated with G 0 /G 1 arrest, and G 2 /M arrest depending upon concentrations. Cell cycle blockade was associated with reduced amounts of cyclin D1/2, cyclin E, Cdk2, Cdk4, and Cdk6 and increased levels of the Cdk inhibitory proteins (Cip1/p21 and Kip1/p27). In addition, labedipinedilol-A also induced apoptosis in PC-3 cells, as determined by using Hoechst 33342 staining, DNA fragmentation, and Annexin V staining assay. Furthermore, labedipinedilol-A triggered the mitochondrial apoptotic pathway, as indicated by increasing the expression of Bax, but decreasing the level of Bcl-2, resulting in mitochondrial membrane potential loss, cytochrome c release, and activation of caspase-9 and -3. We further investigated the role of MAPK cascades in the anti-proliferative and apoptosis effects of labedipinedilol-A, and confirmed that labedipinedilol-A could activate JNK1/2 but not p38 in both cell lines. Unlike JNK1/2, however, labedipinedilol-A treatment resulted in down-regulation of phospho-ERK1/2 expression. We concluded that labedipinedilol-A possessed the growth-suppressive and apoptotic effects on LNCaP and PC-3 cells by its α 1 -adrenoceptor blockade, and the apoptotic effects of labedipinedilol-A primarily through

Carbon adaptation influence the antagonistic ability of ...

African Journals Online (AJOL)

Jane

2011-10-24

Oct 24, 2011 ... INTRODUCTION. The use of antagonistic bacteria to control soil-borne ... plant was used to evaluate the antifungal activities of antagonistic bacteria. ..... antagonistic bacteria and cloning of its phenazine carboxylic acid genes.

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

International Nuclear Information System (INIS)

Sharma, N.K.

2013-01-01

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

Stimulant effects of adenosine antagonists on operant behavior: differential actions of selective A2A and A1 antagonists

Science.gov (United States)

Randall, Patrick A.; Nunes, Eric J.; Janniere, Simone L.; Stopper, Colin M.; Farrar, Andrew M.; Sager, Thomas N.; Baqi, Younis; Hockemeyer, Jörg; Müller, Christa E.

2012-01-01

Rationale Adenosine A2A antagonists can reverse many of the behavioral effects of dopamine antagonists, including actions on instrumental behavior. However, little is known about the effects of selective adenosine antagonists on operant behavior when these drugs are administered alone. Objective The present studies were undertaken to investigate the potential for rate-dependent stimulant effects of both selective and nonselective adenosine antagonists. Methods Six drugs were tested: two nonselective adenosine antagonists (caffeine and theophylline), two adenosine A1 antagonists (DPCPX and CPT), and two adenosine A2A antagonists (istradefylline (KW6002) and MSX-3). Two schedules of reinforcement were employed; a fixed interval 240-s (FI-240 sec) schedule was used to generate low baseline rates of responding and a fixed ratio 20 (FR20) schedule generated high rates. Results Caffeine and theophylline produced rate-dependent effects on lever pressing, increasing responding on the FI-240 sec schedule but decreasing responding on the FR20 schedule. The A2A antagonists MSX-3 and istradefylline increased FI-240 sec lever pressing but did not suppress FR20 lever pressing in the dose range tested. In fact, there was a tendency for istradefylline to increase FR20 responding at a moderate dose. A1 antagonists failed to increase lever pressing rate, but DPCPX decreased FR20 responding at higher doses. Conclusions These results suggest that adenosine A2A antagonists enhance operant response rates, but A1 antagonists do not. The involvement of adenosine A2A receptors in regulating aspects of instrumental response output and behavioral activation may have implications for the treatment of effort-related psychiatric dysfunctions, such as psychomotor slowing and anergia in depression. PMID:21347642

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: patrick.mccormick@camhpet.ca; 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)

2008-01-15

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

Calcium antagonistic effects of Chinese crude drugs: Preliminary investigation and evaluation by 45Ca

International Nuclear Information System (INIS)

Liu Ning; Yang Yuanyou; Mo Shangwu; Liao Jiali; Jin Jiannan

2005-01-01

Coronary and other diseases in cardiac or brain blood vessels are considered to be due to the excessive influx of Ca 2+ into cytoplasm. If Ca 2+ channels in cell membrane are blocked by medicines or other substances with considerable calcium antagonistic effects, these diseases might be cured or controlled. The influence of some Chinese crude drugs, including Crocus sativus, Carthamus tinctorius, Ginkgo biloba and Bulbus allii macrostemi on Ca 2+ influx in isolated rat aortas was investigated by using 45 Ca as a radioactive tracer, and their calcium antagonistic effects were evaluated. It can be noted that Ca 2+ uptake in isolated rat aorta rings in normal physiological status was not markedly altered by these drugs, whereas the Ca 2+ influxes induced by norepinephrine of 1.2 μmol/L and KCl of 100 mmol/L were significantly inhibited by Crocus, Carthamus and Bulbus in a concentration-dependent manner, but not by Ginkgo. The results show that extracellular Ca 2+ influx through receptor-operated Ca 2+ channels and potential-dependent Ca 2+ channels can be blocked by Crocus, Carthamus and Bulbus. This implies that these Chinese crude drugs have obvious calcium antagonistic effects

Microbial herd protection mediated by antagonistic interaction in polymicrobial communities.

Science.gov (United States)

Wong, Megan; Liang, Xiaoye; Smart, Matt; Tang, Le; Moore, Richard; Ingalls, Brian; Dong, Tao G

2016-09-16

In the host and natural environments, microbes often exist in complex multispecies communities. The molecular mechanisms through which such communities develop and persist - despite significant antagonistic interactions between species - are not well understood. The type VI secretion system (T6SS) is a lethal weapon commonly employed by Gram-negative bacteria to inhibit neighboring species through delivery of toxic effectors. It is well established that intra-species protection is conferred by immunity proteins that neutralize effector toxicities. By contrast, the mechanisms for interspecies protection are not clear. Here we use two T6SS active antagonistic bacteria, Aeromonas hydrophila (AH) and Vibrio cholerae (VC), to demonstrate that interspecies protection is dependent on effectors. AH and VC do not share conserved immunity genes but could equally co-exist in a mixture. However, mutants lacking the T6SS or effectors were effectively eliminated by the other competing wild type. Time-lapse microscopy analyses show that mutually lethal interactions drive the segregation of mixed species into distinct single-species clusters by eliminating interspersed single cells. Cluster formation provides herd protection by abolishing lethal interaction inside each cluster and restricting it to the boundary. Using an agent-based modeling approach, we simulated the antagonistic interactions of two hypothetical species. The resulting simulations recapitulate our experimental observation. These results provide mechanistic insights for the general role of microbial weapons in determining the structures of complex multispecies communities. Investigating the warfare of microbes allows us to better understand the ecological relationships in complex microbial communities such as the human microbiota. Here we use the T6SS, a deadly bacterial weapon, as a model to demonstrate the importance of lethal interactions in determining community structures and exchange of genetic materials

Microbial Herd Protection Mediated by Antagonistic Interaction in Polymicrobial Communities

Science.gov (United States)

Wong, Megan J. Q.; Liang, Xiaoye; Smart, Matt; Tang, Le; Moore, Richard; Ingalls, Brian

2016-01-01

ABSTRACT In host and natural environments, microbes often exist in complex multispecies communities. The molecular mechanisms through which such communities develop and persist, despite significant antagonistic interactions between species, are not well understood. The type VI secretion system (T6SS) is a lethal weapon commonly employed by Gram-negative bacteria to inhibit neighboring species through the delivery of toxic effectors. It is well established that intraspecies protection is conferred by immunity proteins that neutralize effector toxicities. In contrast, the mechanisms for interspecies protection are not clear. Here we use two T6SS-active antagonistic bacterial species, Aeromonas hydrophila and Vibrio cholerae, to demonstrate that interspecies protection is dependent on effectors. A. hydrophila and V. cholerae do not share conserved immunity genes but could coexist equally in a mixture. However, mutants lacking the T6SS or effectors were effectively eliminated by the competing wild-type strain. Time-lapse microscopic analyses showed that mutually lethal interactions drive the segregation of mixed species into distinct single-species clusters by eliminating interspersed single cells. Cluster formation provides herd protection by abolishing lethal interactions inside each cluster and restricting the interactions to the boundary. Using an agent-based modeling approach, we simulated the antagonistic interactions of two hypothetical species. The resulting simulations recapitulated our experimental observations. These results provide mechanistic insights regarding the general role of microbial weapons in determining the structures of complex multispecies communities. IMPORTANCE Investigating the warfare of microbes allows us to better understand the ecological relationships in complex microbial communities such as the human microbiota. Here we use the T6SS, a deadly bacterial weapon, as a model to demonstrate the importance of lethal interactions in

Identification of Glycyrrhiza as the rikkunshito constituent with the highest antagonistic potential on heterologously expressed 5HT3A receptors due to the action of flavonoids

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Robin eHerbrechter

2015-07-01

Full Text Available The traditional Japanese phytomedicine rikkunshito is traditionally used for the treatment of gastrointestinal motility disorders, cachexia and nausea. These effects indicate 5-HT3 receptor antagonism, due to the involvement of these receptors in such pathophysiological processes. E.g. setrons, specific 5-HT3 receptor antagonists are the strongest antiemetics, developed so far. Therefore, the antagonistic effects of the eight rikkunshito constituents at heterologously expressed 5-HT3A receptors were analyzed using the two-electrode voltage-clamp technique. The results indicate that tinctures from Aurantii, Ginseng, Zingiberis, Atractylodis and Glycyrrhiza inhibited the 5-HT3A receptor response, whereas the tinctures of Poria cocos, Jujubae and Pinellia exhibited no effect. Surprisingly, the strongest antagonism was found for Glycyrrhiza, whereas the Zingiberis tincture, which is considered to be primarily responsible for the effect of rikkunshito, exhibited the weakest antagonist of 5-HT3A receptors. Rikkunshito contains various vanilloids, ginsenosides and flavonoids, a portion of which show an antagonistic effect on 5-HT3 receptors. A screening of the established ingredients of the active rikkunshito constituents and related substances lead to the identification of new antagonists within the class of flavonoids. The flavonoids (--liquiritigenin, glabridin and licochalcone A from Glycyrrhiza species were found to be the most effective inhibitors of the 5-HT-induced currents in the screening. The flavonoids (--liquiritigenin and hesperetin from Aurantii inhibited the receptor response in a non-competitive manner, whereas glabridin and licochalcone A exhibited a potential competitive antagonism. Furthermore, licochalcone A acts as a partial antagonist of 5-HT3A receptors. Thus, this study reveals new 5-HT3A receptor antagonists with the aid of increasing the comprehension of the complex effects of rikkunshito.

Effect of hypolipidemic drugs on basal and stimulated adenylate cyclase activity in tumor cells

International Nuclear Information System (INIS)

Bershtein, L.M.; Kovaleva, I.G.; Rozenberg, O.A.

1986-01-01

This paper studies adenylate cyclase acticvity in Ehrlich's ascites carcinoma (EAC) cells during administration of drugs with a hypolipidemic action. Seven to eight days before they were killed, male mice ingested the antidiabetic biguanide phenformin, and the phospholipid-containing preparation Essentiale in drinking water. The cAMP formed was isolated by chromatography on Silufol plates after incubation of the enzyme preparation with tritium-ATP, or was determined by the competitive binding method with protein. It is shown that despite the possible differences in the concrete mechanism of action of the hypolipidemic agents chosen for study on the cyclase system, the use of such agents, offers definite prospects for oriented modification of the hormone sensitivity of tumor cells

Excitatory amino acid receptor antagonists

DEFF Research Database (Denmark)

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

1997-01-01

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...

Comprehensive behavioral analysis of pituitary adenylate cyclase-activating polypeptide (PACAP knockout mice

Directory of Open Access Journals (Sweden)

Satoko eHattori

2012-10-01

Full Text Available Pituitary adenylate cyclase-activating polypeptide (PACAP is a neuropeptide acting as a neurotransmitter, neuromodulator, or neurotrophic factor. PACAP is widely expressed throughout the brain and exerts its functions through the PACAP-specific receptor (PAC1. Recent studies reveal that genetic variants of the PACAP and PAC1 genes are associated with mental disorders, and several behavioral abnormalities of PACAP knockout (KO mice are reported. However, an insufficient number of backcrosses was made using PACAP KO mice on the C57BL/6J background due to their postnatal mortality. To elucidate the effects of PACAP on neuropsychiatric function, the PACAP gene was knocked out in F1 hybrid mice (C57BL/6J x 129SvEv for appropriate control of the genetic background. The PACAP KO mice were then subjected to a behavioral test battery. PACAP deficiency had no significant effects on neurological screen. As shown previously, the mice exhibited significantly increased locomotor activity in a novel environment and abnormal anxiety-like behavior, while no obvious differences between genotypes were shown in home cage activity. In contrast to previous reports, the PACAP KO mice showed normal prepulse inhibition and slightly decreased depression-like behavior. Previous study demonstrates that the social interaction in a resident-intruder test was decreased in PACAP KO mice. On the other hand, we showed that PACAP KO mice exhibited increased social interaction in Crawley’s three-chamber social approach test, although PACAP KO had no significant impact on social interaction in a home cage. PACAP KO mice also exhibited mild performance deficit in working memory in an eight-arm radial maze and the T-maze, while they did not show any significant abnormalities in the left-right discrimination task in the T-maze. These results suggest that PACAP has an important role in the regulation of locomotor activity, social behavior, anxiety-like behavior and, potentially

Physiological desensitization of carbohydrate permeases and adenylate cyclase to regulation by the phosphoenolpyruvate:sugar phosphotransferase system in Escherichia coli and Salmonella typhimurium. Involvement of adenosine cyclic 3',5'-phosphate and inducer.

Science.gov (United States)

Saier, M H; Keeler, D K; Feucht, B U

1982-03-10

Adenylate cyclase and a number of carbohydrate transport systems are subject to regulation by the phosphoenolpyruvate:sugar phosphotransferase system. These sensitive carbohydrate transport systems are desensitized to regulation by the phosphotransferase system, and adenylate cyclase is deactivated when cells are grown in medium containing cyclic AMP. These effects are specific for cyclic AMP and are potentiated by the genetic loss of cyclic AMP phosphodiesterase. Inclusion in the growth medium of an inducer of a sensitive transport system also promotes desensitization of that particular transport system. Inducer-promoted desensitization is specific for the particular target transport system, while cyclic AMP-promoted desensitization is general and affects several systems. Desensitization of the permeases to regulation, and inactivation of adenylate cyclase, are slow processes which are blocked by chloramphenicol and are therefore presumably dependent on protein synthesis. Several sugar substrates of the phosphotransferase system are capable of regulating the sensitive carbohydrate transport systems. The evidence suggests that desensitization to this regulation does not result from a direct effect on the functioning of Enzyme I, a small heat-stable protein of the phosphotransferase system, HPr, or an Enzyme II of the phosphotransferase system, but specifically uncouples the permease systems from regulation.

A novel BLyS antagonist peptide designed based on the 3-D complex structure of BCMA and BLyS

International Nuclear Information System (INIS)

Sun Jian; Feng Jiannan; Li Yan; Shen Beifen

2006-01-01

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

The effect of opioid antagonists on synergism between dexketoprofen and tramadol.

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Zegpi, C; Gonzalez, C; Pinardi, G; Miranda, H F

2009-10-01

The antinociceptive activity of dexketoprofen was studied in mice using the formalin assay for orofacial pain. The interaction between dexketoprofen and co-administered tramadol was studied using isobolographic analysis. The intraperitoneal administration of dexketoprofen or tramadol, showed dose-dependent antinociceptive activity in both phases of the assay. When administered together, the interaction was mildly synergistic during the first phase, and antagonistic in the second phase. Selective opioid receptor antagonists where used in order to measure the analgesic activity of tramadol in other regions of the CNS. The co-administration of dexketoprofen and tramadol, with previous administration of naltrexone, showed high synergistic activity during the first phase, and less but still synergistic during the second. When using naltrindole, the interaction was mildly more synergistic than the mixture dexketoprofen+tramadol during both phases. Using norbinaltorphimine, the interaction was synergistic in both phases, more marked in the second. These results suggest that the opioid activity of tramadol has an inhibiting effect in antinociceptive activity of the interaction between dexketoprofen and tramadol during the inflammatory (late) stages of pain.

Antagonistic evaluation of Trichodermaviride and Aspergillusflavus against wood-decay fungus Pleurotusostreatus

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Erwin; Iskandar, E.; Husien, N.

2018-04-01

Pleurotusostreatus cultivation is often limited by the presence of antagonistic microorganisms that can also grow together on a variety of substrates that are used as growth media of P. ostreatus. As a preliminary study, this research aims to evaluate the antagonism of Trichodermaviride and Aspergillusflavus in interacting with the P.ostreatus fungus by in-vitro. An antagonism test using a dual culture method of these fungi with 1 month incubation time on Poteto Dextrose Agar (PDA) media was performed. Evaluation of the antagonistic properties of these fungi is conducted through macroscopic and microscopic observations. Macroscopically, the growth of T. viride and A. flavus mycelium showed that both colonies were more dominant than P. ostreatus colonies. Microscopically, hyphae of T. viride and A. flavus indicate the presence of very strong micoparasitic properties that characterized by attachment and convolution of both hyphae to P. ostreatus hyphae. It was concluded thatthe growth of T. viride and A. flavus fungi was more dominant and had potential as an inhibiting agent of P. ostreatus fungal growth, respectively, in dual culture on PDA media.

Biological Control of Apple Anthracnose by Paenibacillus polymyxa APEC128, an Antagonistic Rhizobacterium.

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Kim, Young Soo; Balaraju, Kotnala; Jeon, Yongho

2016-06-01

The present study investigated the suppression of the disease development of anthracnose caused by Colletotrichum gloeosporioides and C. acutatum in harvested apples using an antagonistic rhizobacterium Paenibacillus polymyxa APEC128 (APEC128). Out of 30 bacterial isolates from apple rhizosphere screened for antagonistic activity, the most effective strain was APEC128 as inferred from the size of the inhibition zone. This strain showed a greater growth in brain-heart infusion (BHI) broth compared to other growth media. There was a reduction in anthracnose symptoms caused by the two fungal pathogens in harvested apples after their treatment with APEC128 in comparison with non-treated control. This effect is explained by the increased production of protease and amylase by APEC128, which might have inhibited mycelial growth. In apples treated with different APEC128 suspensions, the disease caused by C. gloeosporioides and C. acutatum was greatly suppressed (by 83.6% and 79%, respectively) in treatments with the concentration of 1 × 10(8) colony forming units (cfu)/ml compared to other lower dosages, suggesting that the suppression of anthracnose development on harvested apples is dose-dependent. These results indicated that APEC128 is one of the promising agents in the biocontrol of apple anthracnose, which might help to increase the shelf-life of apple fruit during the post-harvest period.

Combined treatment with a β3 -adrenergic receptor agonist and a muscarinic receptor antagonist inhibits detrusor overactivity induced by cold stress in spontaneously hypertensive rats.

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Imamura, Tetsuya; Ogawa, Teruyuki; Minagawa, Tomonori; Nagai, Takashi; Suzuki, Toshiro; Saito, Tetsuichi; Yokoyama, Hitoshi; Nakazawa, Masaki; Ishizuka, Osamu

2017-04-01

This study determined if combined treatment with the muscarinic receptor (MR) antagonist solifenacin and the β 3 -adrenergic receptor (AR) agonist mirabegron could inhibit detrusor overactivity induced by cold stress in spontaneously hypertensive rats (SHRs). Thirty-two female 10-week-old SHRs were fed an 8% NaCl-supplemented diet for 4 weeks. Cystometric measurements of the unanesthetized, unrestricted rats were performed at room temperature (RT, 27 ± 2°C) for 20 min. The rats were then intravenously administered vehicle, 0.1 mg/kg solifenacin alone, 0.1 mg/kg mirabegron alone, or the combination of 0.1 mg/kg mirabegron and 0.1 mg/kg solifenacin (n = 8 each group). Five minutes later, the treated rats were exposed to low temperature (LT, 4 ± 2°C) for 40 min. Finally, the rats were returned to RT. After the cystometric investigations, the β 3 -ARs and M 3 -MRs expressed within the urinary bladders were analyzed. Just after transfer from RT to LT, vehicle-, solifenacin-, and mirabegron-treated SHRs exhibited detrusor overactivity that significantly decreased voiding interval and bladder capacity. However, treatment with the combination of solifenacin and mirabegron partially inhibited the cold stress-induced detrusor overactivity patterns. The decreases of voiding interval and bladder capacity in the combination-treated rats were significantly inhibited compared to other groups. Within the urinary bladders, there were no differences between expression levels of M 3 -MR and β 3 -AR mRNA. The tissue distribution of M 3 -MRs was similar to that of the β 3 -ARs. This study suggested that the combination of solifenacin and mirabegron act synergistically to inhibit the cold stress-induced detrusor overactivity in SHRs. Neurourol. Urodynam. 36:1026-1033, 2017. © 2016 The Authors. Neurourology and Urodynamics Published by Wiley Periodicals, Inc. © 2016 The Authors. Neurourology and Urodynamics Published by Wiley Periodicals, Inc.

Effect of methysergide on pudendal inhibition of micturition reflex in cats.

Science.gov (United States)

Matsuta, Yosuke; Schwen, Zeyad; Mally, Abhijith D; Shen, Bing; Wang, Jicheng; Roppolo, James R; de Groat, William C; Tai, Changfeng

2013-09-01

The role of 5-HT2 and opioid receptors in pudendal inhibition of bladder activity induced by intravesical infusion of saline or 0.25% acetic acid (AA) was investigated in anesthetized cats using methysergide (a 5-HT2 receptor antagonist) and naloxone (an opioid receptor antagonist). AA irritated the bladder and significantly (Preflex bladder activity and interact with opioid mechanisms in micturition reflex pathway. Understanding neurotransmitter mechanisms underlying pudendal neuromodulation is important for the development of new treatments for bladder disorders. Copyright © 2013 Elsevier Inc. All rights reserved.

High Concentrations of Tranexamic Acid Inhibit Ionotropic Glutamate Receptors.

Science.gov (United States)

Lecker, Irene; Wang, Dian-Shi; Kaneshwaran, Kirusanthy; Mazer, C David; Orser, Beverley A

2017-07-01

The antifibrinolytic drug tranexamic acid is structurally similar to the amino acid glycine and may cause seizures and myoclonus by acting as a competitive antagonist of glycine receptors. Glycine is an obligatory co-agonist of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors. Thus, it is plausible that tranexamic acid inhibits NMDA receptors by acting as a competitive antagonist at the glycine binding site. The aim of this study was to determine whether tranexamic acid inhibits NMDA receptors, as well as α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and kainate subtypes of ionotropic glutamate receptors. Tranexamic acid modulation of NMDA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, and kainate receptors was studied using whole cell voltage-clamp recordings of current from cultured mouse hippocampal neurons. Tranexamic acid rapidly and reversibly inhibited NMDA receptors (half maximal inhibitory concentration = 241 ± 45 mM, mean ± SD; 95% CI, 200 to 281; n = 5) and shifted the glycine concentration-response curve for NMDA-evoked current to the right. Tranexamic acid also inhibited α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (half maximal inhibitory concentration = 231 ± 91 mM; 95% CI, 148 to 314; n = 5 to 6) and kainate receptors (half maximal inhibitory concentration = 90 ± 24 mM; 95% CI, 68 to 112; n = 5). Tranexamic acid inhibits NMDA receptors likely by reducing the binding of the co-agonist glycine and also inhibits α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and kainate receptors. Receptor blockade occurs at high millimolar concentrations of tranexamic acid, similar to the concentrations that occur after topical application to peripheral tissues. Glutamate receptors in tissues including bone, heart, and nerves play various physiologic roles, and tranexamic acid inhibition of these receptors may contribute to adverse drug effects.

Antagonistic Activity Of Endophytic Bacteria Isolated From Mentha Rotundifolia L.

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Elhartiti Abla

2015-08-01

Full Text Available Abstract This study is implemented for the isolation purification and identification of endophytic bacteria which produces antifungal substances from the roots of Mentha rotundifolia L. The 59 obtained bacterial isolates were tested for their antagonistic activity by the dual confrontation against the phytopathogenic fungi Fusarium oxysporum Aspergillus Niger and Botrytis cinerea. Eight bacterial strains were selected for their strong antifungal activity. These are strains M21 M23 M3a M4 M14d and M3c which belong to the family Bacillaceae M12 and M3b which belongs to the family of Pseudomonadaceae. Among these three bacterial strains namely M21 M23 and M12 induce 70 of inhibition of mycelial growth of phytopathogenic fungi Fusarium oxysporum and Aspergillus Niger while the five bacterial strains M3a M3c M3b M4 and M14d have proved to be effective in inhibiting more than 60 of mycelial growth of Botrytis cinerea.

Calcium-antagonists and islet function. V. Effect of R33711

Energy Technology Data Exchange (ETDEWEB)

Malaisse, W J; Sener, A; Devis, G; Somers, G [Brussels Univ. (Belgium). Lab. of Experimental Medicine

1976-11-01

R33711, a new drug with presumed potent calcium-antagonistic property, was found to suppress the insulinotropic action of glucose und gliclazide but not that of theophylline. A 0.2 ..mu..M concentration of R33711 was sufficient to abolish glucose-induced insulin release. At this concentration, R33711 inhibited the net uptake of /sup 45/Ca/sup 2 +/ by isolated islets, whether in the absence or presence of either glucose or sulfonylurea. In the isolated islets, R33711 failed to affect the glucose-stimulated production of lactate, the rate of /sup 45/Ca/sup 2 +/ efflux, the inhibitory action of glucose upon such an efflux and its increase in response to theophylline. These data are compatible with the view that R33711 inhibits entry of Ca/sup 2 +/ into the B-cell and that integrity of such an inward cationic movement usually plays a permissive role in the maintenance of the Ca/sup 2 +/-dependent insulin secretory process.

GSK3β inhibition promotes synaptogenesis in Drosophila and mammalian neurons.

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Germán Cuesto

Full Text Available The PI3K-dependent activation of AKT results in the inhibition of GSK3β in most signaling pathways. These kinases regulate multiple neuronal processes including the control of synapse number as shown for Drosophila and rodents. Alzheimer disease's patients exhibit high levels of circulating GSK3β and, consequently, pharmacological strategies based on GSK3β antagonists have been designed. The approach, however, has yielded inconclusive results so far. Here, we carried out a comparative study in Drosophila and rats addressing the role of GSK3β in synaptogenesis. In flies, the genetic inhibition of the shaggy-encoded GSK3β increases the number of synapses, while its upregulation leads to synapse loss. Likewise, in three weeks cultured rat hippocampal neurons, the pharmacological inhibition of GSK3β increases synapse density and Synapsin expression. However, experiments on younger cultures (12 days yielded an opposite effect, a reduction of synapse density. This unexpected finding seems to unveil an age- and dosage-dependent differential response of mammalian neurons to the stimulation/inhibition of GSK3β, a feature that must be considered in the context of human adult neurogenesis and pharmacological treatments for Alzheimer's disease based on GSK3β antagonists.

Effects of TNF antagonists on immune and neuroendocrine system

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M. Cutolo

2011-09-01

Full Text Available In the article, the literature on the effects of TNFa-antagonists (etanercept, infliximab and adalimumab on the immune system is reviewed. These biologic agents are employed in chronic inflammatory diseases such as rheumatoid arthritis, seronegative spondyloarthritides, as well as psoriasis and Crohn’s disease. The differences of these drugs, testified by the different effects on the immune response, are discussed. These molecules exert their effect through cytokine inhibition, but they present striking differences since they can modulate macrophage activity, T cells apoptosis, leukocyte migration, and angiogenesis to a different degree. Some studies showed that these agents also affect the hypothalamo- pituitary-adrenal axis. The potential immunogenicity of these biologic agents is also discussed.

Impairment of GABA transporter GAT-1 terminates cortical recurrent network activity via enhanced phasic inhibition

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Daniel Simon Razik

2013-09-01

Full Text Available In the central nervous system, GABA transporters (GATs very efficiently clear synaptically released GABA from the extracellular space, and thus exert a tight control on GABAergic inhibition. In neocortex, GABAergic inhibition is heavily recruited during recurrent phases of spontaneous action potential activity which alternate with neuronally quiet periods. Therefore, such activity should be quite sensitive to minute alterations of GAT function. Here, we explored the effects of a gradual impairment of GAT-1 and GAT-2/3 on spontaneous recurrent network activity – termed network bursts and silent periods – in organotypic slice cultures of rat neocortex. The GAT-1 specific antagonist NO-711 depressed activity already at nanomolar concentrations (IC50 for depression of spontaneous multiunit firing rate of 42 nM, reaching a level of 80% at 500-1000 nM. By contrast, the GAT-2/3 preferring antagonist SNAP-5114 had weaker and less consistent effects. Several lines of evidence pointed towards an enhancement of phasic GABAergic inhibition as the dominant activity-depressing mechanism: network bursts were drastically shortened, phasic GABAergic currents decayed slower, and neuronal excitability during ongoing activity was diminished. In silent periods, NO-711 had little effect on neuronal excitability or membrane resistance, quite in contrast to the effects of muscimol, a GABA mimetic which activates GABAA receptors tonically. Our results suggest that an enhancement of phasic GABAergic inhibition efficiently curtails cortical recurrent activity and may mediate antiepileptic effects of therapeutically relevant concentrations of GAT-1 antagonists.

Cardiometabolic effects of genetic upregulation of the interleukin 1 receptor antagonist

DEFF Research Database (Denmark)

2015-01-01

BACKGROUND: To investigate potential cardiovascular and other effects of long-term pharmacological interleukin 1 (IL-1) inhibition, we studied genetic variants that produce inhibition of IL-1, a master regulator of inflammation. METHODS: We created a genetic score combining the effects of alleles...... of two common variants (rs6743376 and rs1542176) that are located upstream of IL1RN, the gene encoding the IL-1 receptor antagonist (IL-1Ra; an endogenous inhibitor of both IL-1α and IL-1β); both alleles increase soluble IL-1Ra protein concentration. We compared effects on inflammation biomarkers...... of this genetic score with those of anakinra, the recombinant form of IL-1Ra, which has previously been studied in randomised trials of rheumatoid arthritis and other inflammatory disorders. In primary analyses, we investigated the score in relation to rheumatoid arthritis and four cardiometabolic diseases (type...

Medicinal chemistry of small molecule CCR5 antagonists for blocking HIV-1 entry: a review of structural evolution.

Science.gov (United States)

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

2014-01-01

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.

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

Science.gov (United States)

Michinaga, Shotaro; Nagase, Marina; Matsuyama, Emi; Yamanaka, Daisuke; Seno, Naoki; Fuka, Mayu; Yamamoto, Yui; Koyama, Yutaka

2014-01-01

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.

Serotonin antagonists fail to alter MDMA self-administration in rats.

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Schenk, Susan; Foote, Jason; Aronsen, Dane; Bukholt, Natasha; Highgate, Quenten; Van de Wetering, Ross; Webster, Jeremy

2016-09-01

Acute exposure to ±3,4-methylenedioxymethamphetamine (MDMA) preferentially increases release of serotonin (5-HT), and a role of 5-HT in many of the behavioral effects of acute exposure to MDMA has been demonstrated. A role of 5-HT in MDMA self-administration in rats has not, however, been adequately determined. Therefore, the present study measured the effect of pharmacological manipulation of some 5-HT receptor subtypes on self-administration of MDMA. Rats received extensive experience with self-administered MDMA prior to tests with 5-HT ligands. Doses of the 5-HT1A antagonist, WAY 100635 (0.1-1.0mg/kg), 5-HT1B antagonist, GR 127935 (1.0-3.0mg/kg), and the 5-HT2A antagonist, ketanserin (1.0-3.0mg/kg) that have previously been shown to decrease self-administration of other psychostimulants and that decreased MDMA-produced hyperactivity in the present study did not alter MDMA self-administration. Experimenter-administered injections of MDMA (10.0mg/kg, ip) reinstated extinguished drug-taking behavior, but this also was not decreased by any of the antagonists. In contrast, both WAY 100635 and ketanserin, but not GR 127935, decreased cocaine-produced drug seeking in rats that had been trained to self-administered cocaine. The 5-HT1A agonist, 8-OH-DPAT (0.1-1.0mg/kg), but not the 5-HT1B/1A agonist, RU 24969 (0.3-3.0mg/kg), decreased drug-seeking produced by the reintroduction of a light stimulus that had been paired with self-administered MDMA infusions. These findings suggest a limited role of activation of 5-HT1A, 5-HT1B or 5-HT2 receptor mechanisms in MDMA self-administration or in MDMA-produced drug-seeking following extinction. The data suggest, however, that 5-HT1A agonists inhibit cue-induced drug-seeking following extinction of MDMA self-administration and might, therefore, be useful adjuncts to therapies to limit relapse to MDMA use. Copyright © 2016 Elsevier Inc. All rights reserved.

EVALUATION OF PHOSPHATE SOLUBILIZING MICROORGANISMS (PSMs FROM RHIZOSPHERE SOIL OF DIFFERENT CROP PLANTS AND ITS ANTAGONISTIC ACTIVITY

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Samikan Krishnakumar

2014-04-01

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.

Naloxone : actions of an antagonist

NARCIS (Netherlands)

Dorp, Eveline Louise Arianna van

2009-01-01

The opioid antagonist naloxone has a special place in pharmacology – it has no intrinsic action of its own, but it is able to save lives in the case of life threatening side-effects caused by other drugs. Naloxone is an antagonist for all opioid receptors, but most specifically for the μ-opioid

A novel antagonist of CRTH2 blocks eosinophil release from bone marrow, chemotaxis and respiratory burst

DEFF Research Database (Denmark)

Royer, J F; Schratl, P; Lorenz, S

2007-01-01

developed small molecule antagonist of CRTH2, Cay10471, on eosinophil function with respect to recruitment, respiratory burst and degranulation. METHODS: Chemotaxis of guinea pig bone marrow eosinophils and human peripheral blood eosinophils were determined using microBoyden chambers. Eosinophil release...... from bone marrow was investigated in the in situ perfused guinea pig hind limb preparation. Respiratory burst and degranulation were measured by flow cytometry. RESULTS: Cay10471 bound with high affinity to recombinant human and guinea pig CRTH2, but not DP, receptors. The antagonist prevented the PGD......(2)-induced release of eosinophils from guinea pig bone marrow, and inhibited the chemotaxis of guinea pig bone marrow eosinophils and human peripheral blood eosinophils. Pretreatment with PGD(2) primed eosinophils for chemotaxis towards eotaxin, and this effect was prevented by Cay10471. In contrast...

Design and synthesis of aryloxypropanolamine as β3-adrenergic receptor antagonist in cancer and lipolysis.

Science.gov (United States)

Jin, Jiyu; Miao, Chunxiao; Wang, Zhilong; Zhang, Wanli; Zhang, Xiongwen; Xie, Xin; Lu, Wei

2018-04-25

β-adrenergic receptors (β-ARs) are broadly distributed in various tissues and regulate a panel of important physiological functions and disease states including cancer. Above all, β 3 -adrenergic receptor (β 3 -AR) plays a significant role in regulating lipolysis and thermogenesis in adipose tissue. In this study, we designed and synthesized a series of novel L-748,337 derivatives as selective human β 3 -AR antagonists. Among all the tested L-748,337 analogs, compound 23d was found to display 23-fold more potent β 3 -AR antagonist activity (EC 50  = 0.5117 nM) than L-748,337 (EC 50  = 11.91 nM). In vivo, compound 23d could alleviate weight loss and inhibit tumor growth in C26 tumor cachexia animal model. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Targeting NK-1 Receptors to Prevent and Treat Pancreatic Cancer: A New Therapeutic Approach

International Nuclear Information System (INIS)

Muñoz, Miguel; Coveñas, Rafael

2015-01-01

Pancreatic cancer (PC) is the fourth leading cause of cancer related-deaths in both men and women, and the 1- and 5-year relative survival rates are 25% and 6%, respectively. It is known that smoking, alcoholism and psychological stress are risk factors that can promote PC and increase PC progression. To date, the prevention of PC is crucial because there is no curative treatment. After binding to the neurokinin-1 (NK-1) receptor (a receptor coupled to the stimulatory G-protein Gαs that activates adenylate cyclase), the peptide substance P (SP)—at high concentrations—is involved in many pathophysiological functions, such as depression, smoking, alcoholism, chronic inflammation and cancer. It is known that PC cells and samples express NK-1 receptors; that the NK-1 receptor is overexpressed in PC cells in comparison with non-tumor cells, and that nanomolar concentrations of SP induce PC cell proliferation. By contrast, NK-1 receptor antagonists exert antidepressive, anxiolytic and anti-inflammatory effects and anti-alcohol addiction. These antagonists also exert an antitumor action since in vitro they inhibit PC cell proliferation (PC cells death by apoptosis), and in a xenograft PC mouse model they exert both antitumor and anti-angiogenic actions. NK-1 receptor antagonists could be used for the treatment of PC and hence the NK-1 receptor could be a new promising therapeutic target in PC

Targeting NK-1 Receptors to Prevent and Treat Pancreatic Cancer: A New Therapeutic Approach

Energy Technology Data Exchange (ETDEWEB)

Muñoz, Miguel, E-mail: mmunoz@cica.es [Research Laboratory on Neuropeptides (IBIS), Virgen del Rocío University Hospital, 41013 Sevilla (Spain); Coveñas, Rafael [Laboratory of Neuroanatomy of the Peptidergic System (Lab. 14), Institute of Neurosciences of Castilla y León (INCYL), University of Salamanca, 37008 Salamanca (Spain)

2015-07-06

Pancreatic cancer (PC) is the fourth leading cause of cancer related-deaths in both men and women, and the 1- and 5-year relative survival rates are 25% and 6%, respectively. It is known that smoking, alcoholism and psychological stress are risk factors that can promote PC and increase PC progression. To date, the prevention of PC is crucial because there is no curative treatment. After binding to the neurokinin-1 (NK-1) receptor (a receptor coupled to the stimulatory G-protein Gαs that activates adenylate cyclase), the peptide substance P (SP)—at high concentrations—is involved in many pathophysiological functions, such as depression, smoking, alcoholism, chronic inflammation and cancer. It is known that PC cells and samples express NK-1 receptors; that the NK-1 receptor is overexpressed in PC cells in comparison with non-tumor cells, and that nanomolar concentrations of SP induce PC cell proliferation. By contrast, NK-1 receptor antagonists exert antidepressive, anxiolytic and anti-inflammatory effects and anti-alcohol addiction. These antagonists also exert an antitumor action since in vitro they inhibit PC cell proliferation (PC cells death by apoptosis), and in a xenograft PC mouse model they exert both antitumor and anti-angiogenic actions. NK-1 receptor antagonists could be used for the treatment of PC and hence the NK-1 receptor could be a new promising therapeutic target in PC.

Agonist and antagonist actions of antipsychotic agents at 5-HT1A receptors: a [35S]GTPgammaS binding study.

Science.gov (United States)

Newman-Tancredi, A; Gavaudan, S; Conte, C; Chaput, C; Touzard, M; Verrièle, L; Audinot, V; Millan, M J

1998-08-21

Recombinant human (h) 5-HT1A receptor-mediated G-protein activation was characterised in membranes of transfected Chinese hamster ovary (CHO) cells by use of guanosine-5'-O-(3-[35S]thio)-triphosphate ([35S]GTPgammaS binding). The potency and efficacy of 21 5-HT receptor agonists and antagonists was determined. The agonists, 5-CT (carboxamidotryptamine) and flesinoxan displayed high affinity (subnanomolar Ki values) and high efficacy (Emax > 90%, relative to 5-HT = 100%). In contrast, ipsapirone, zalospirone and buspirone displayed partial agonist activity. EC50s for agonist stimulation of [35S]GTPgammaS binding correlated well with Ki values from competition binding (r = +0.99). Among the compounds tested for antagonist activity, methiothepin and (+)butaclamol exhibited 'inverse agonist' behaviour, inhibiting basal [35S]GTPgammaS binding. The actions of 17 antipsychotic agents were investigated. Clozapine and several putatively 'atypical' antipsychotic agents, including ziprasidone, quetiapine and tiospirone, exhibited partial agonist activity and marked affinity at h5-HT1A receptors, similar to their affinity at hD2 dopamine receptors. In contrast, risperidone and sertindole displayed low affinity at h5-HT1A receptors and behaved as 'neutral' antagonists, inhibiting 5-HT-stimulated [35S]GTPgammaS binding. Likewise the 'typical' neuroleptics, haloperidol, pimozide, raclopride and chlorpromazine exhibited relatively low affinity and 'neutral' antagonist activity at h5-HT1A receptors with Ki values which correlated with their respective Kb values. The present data show that (i) [35S]GTPgammaS binding is an effective method to evaluate the efficacy and potency of agonists and antagonists at recombinant human 5-HT1A receptors. (ii) Like clozapine, several putatively 'atypical' antipsychotic drugs display balanced serotonin h5-HT1A/dopamine hD2 receptor affinity and partial agonist activity at h5-HT1A receptors. (iii) Several 'typical' and some putatively 'atypical

Nobiletin Stimulates Chloride Secretion in Human Bronchial Epithelia via a cAMP/PKA-Dependent Pathway

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Yuan Hao

2015-08-01

Full Text Available Background/Aims: Nobiletin, a citrus flavonoid isolated from tangerines, alters ion transport functions in intestinal epithelia, and has antagonistic effects on eosinophilic airway inflammation of asthmatic rats. The present study examined the effects of nobiletin on basal short-circuit current (ISC in a human bronchial epithelial cell line (16HBE14o-, and characterized the signal transduction pathways that allowed nobiletin to regulate electrolyte transport. Methods: The ISC measurement technique was used for transepithelial electrical measurements. Intracellular calcium ([Ca2+]i and cAMP were also quantified. Results: Nobiletin stimulated a concentration-dependent increase in ISC, which was due to Cl- secretion. The increase in ISC was inhibited by a cystic fibrosis transmembrane conductance regulator inhibitor (CFTRinh-172, but not by 4,4'-diisothiocyano-stilbene-2,2'-disulphonic acid (DIDS, Chromanol 293B, clotrimazole, or TRAM-34. Nobiletin-stimulated ISC was also sensitive to a protein kinase A (PKA inhibitor, H89, and an adenylate cyclase inhibitor, MDL-12330A. Nobiletin could not stimulate any increase in ISC in a cystic fibrosis (CF cell line, CFBE41o-, which lacked a functional CFTR. Nobiletin stimulated a real-time increase in cAMP, but not [Ca2+]i. Conclusion: Nobiletin stimulated transepithelial Cl- secretion across human bronchial epithelia. The mechanisms involved activation of adenylate cyclase- and cAMP/PKA-dependent pathways, leading to activation of apical CFTR Cl- channels.

Haloperidol Suppresses NF-kappaB to Inhibit Lipopolysaccharide-Induced Pro-Inflammatory Response in RAW 264 Cells.

Science.gov (United States)

Yamamoto, Shunsuke; Ohta, Noriyuki; Matsumoto, Atsuhiro; Horiguchi, Yu; Koide, Moe; Fujino, Yuji

2016-02-04

BACKGROUND Haloperidol, a tranquilizing agent, is administered both to treat symptoms of psychotic disorders and to sedate agitated and delirious patients. Notably, haloperidol has been suggested to inhibit the immune response through unknown mechanisms. We hypothesized that the sedative modulates the immune response via NF-κB. MATERIAL AND METHODS Using flow cytometry, we analyzed the effects of haloperidol on expression CD80 and CD86 in RAW 264 cells and in primary macrophages derived from bone marrow. Secretion of interleukin (IL)-1β, IL-6, and IL-12 p40 was measured by enzyme-linked immunosorbent assay. In addition, NF-κB activation was evaluated using a reporter assay based on secretory embryonic alkaline phosphatase. Finally, synthetic antagonists were used to identify the dopamine receptor that mediates the effects of haloperidol. RESULTS Haloperidol inhibited NF-κB activation, and thereby suppressed expression of CD80, as well as secretion of IL-1β, IL-6, and IL-12 p40. CD80 and IL-6 levels were similarly attenuated by a D2-like receptor antagonist, but not by a D1-like receptor antagonist. CONCLUSIONS The data strongly suggest that haloperidol inhibits the immune response by suppressing NF-kB signaling via the dopamine D2 receptor.

Thermostability promotes the cooperative function of split adenylate kinases.

Science.gov (United States)

Nguyen, Peter Q; Liu, Shirley; Thompson, Jeremy C; Silberg, Jonathan J

2008-05-01

Proteins can often be cleaved to create inactive polypeptides that associate into functional complexes through non-covalent interactions, but little is known about what influences the cooperative function of the ensuing protein fragments. Here, we examine whether protein thermostability affects protein fragment complementation by characterizing the function of split adenylate kinases from the mesophile Bacillus subtilis (AKBs) and the hyperthermophile Thermotoga neapolitana (AKTn). Complementation studies revealed that the split AKTn supported the growth of Escherichia coli with a temperature-sensitive AK, but not the fragmented AKBs. However, weak complementation occurred when the AKBs fragments were fused to polypeptides that strongly associate, and this was enhanced by a Q16L mutation that thermostabilizes the full-length protein. To examine how the split AK homologs differ in structure and function, their catalytic activity, zinc content, and circular dichroism spectra were characterized. The reconstituted AKTn had higher levels of zinc, greater secondary structure, and >10(3)-fold more activity than the AKBs pair, albeit 17-fold less active than full-length AKTn. These findings provide evidence that the design of protein fragments that cooperatively function can be improved by choosing proteins with the greatest thermostability for bisection, and they suggest that this arises because hyperthermophilic protein fragments exhibit greater residual structure compared to their mesophilic counterparts.

The Screening and the Use of Antagonists for Biological Control of Anthracnose of Chilli at Pre-and Post-Harvesting

International Nuclear Information System (INIS)

Piadiang, Nattaya

2006-09-01

A total of 301 of isolates of microorganism were isolated from pepper leaves and fruit skin, including fungi bacteria and yeast. They were tested inhibition of mycelia l growth of Colletotrichum gloeosporioides, a causal agent of anthracnose, on potato dextrose agar (PDA). The result showed that 145 isolate inhibited the growth of mycelia l by 45-70 %. The selected high efficiency antagonists were tested for potential reduce anthracnose lesion development on detected pepper fruit. The selected four isolate antagonists including Y18, YFm1, YFm2 and AC2-1 were finding suitable method test for control of anthracnose disease. The results show that application of antagonistic microorganism before inoculation of C. gloeosporiodes was superior in disease controlling than inoculation regardless the use of pathogen inoculation procedures. Antagonist Y18, YFm1 and YFm2 were test ability in greenhouse, in was found that three isolates have high efficiency for control anthracnose disease. Under field condition, spraying cell suspension of Y18, YFm2 and Yfm1 on pepper fruit before inoculation C. gloeosporioides and cover with plastic bag. 14 day after treatment it was found that Y18, YFm2, YFm1 and control had percentage of fruit disease by 33.33, 40.7, 73.4 and 100 % respectively. When study ability of three isolate in field at found anthracnose disease revealed that Y18 and YFm2 could control of C. gloesporiodides within 12 day after treatment. Addition, YFm2 could control of C. gloeosporidide in field at not found anthracnose high efficiency. The efficiency test of YFm2 for anthracnose controlling on chilli fruit for export were kept at 13 degree C for 18 days. YFm2 showed 100 % control of anthracnose with satisfactory firmness of chilli friut.

Roles of Protein Kinase A and Adenylate Cyclase in Light-Modulated Cellulase Regulation in Trichoderma reesei

Science.gov (United States)

Schuster, André; Tisch, Doris; Seidl-Seiboth, Verena; Kubicek, Christian P.

2012-01-01

The cyclic AMP (cAMP) pathway represents a central signaling cascade with crucial functions in all organisms. Previous studies of Trichoderma reesei (anamorph of Hypocrea jecorina) suggested a function of cAMP signaling in regulation of cellulase gene expression. We were therefore interested in how the crucial components of this pathway, adenylate cyclase (ACY1) and cAMP-dependent protein kinase A (PKA), would affect cellulase gene expression. We found that both ACY1 and PKA catalytic subunit 1 (PKAC1) are involved in regulation of vegetative growth but are not essential for sexual development. Interestingly, our results showed considerably increased transcript abundance of cellulase genes in darkness compared to light (light responsiveness) upon growth on lactose. This effect is strongly enhanced in mutant strains lacking PKAC1 or ACY1. Comparison to the wild type showed that ACY1 has a consistently positive effect on cellulase gene expression in light and darkness, while PKAC1 influences transcript levels of cellulase genes positively in light but negatively in darkness. A function of PKAC1 in light-modulated cellulase gene regulation is also reflected by altered complex formation within the cel6a/cbh2 promoter in light and darkness and in the absence of pkac1. Analysis of transcript levels of cellulase regulator genes indicates that the regulatory output of the cAMP pathway may be established via adjustment of XYR1 abundance. Consequently, both adenylate cyclase and protein kinase A are involved in light-modulated cellulase gene expression in T. reesei and have a dampening effect on the light responsiveness of this process. PMID:22286997

Down-regulation of Cell Surface Cyclic AMP Receptors and Desensitization of Cyclic AMP-stimulated Adenylate Cyclase by Cyclic AMP in Dictyostelium discoideum. Kinetics and Concentration Dependence

NARCIS (Netherlands)

Haastert, Peter J.M. van

1987-01-01

cAMP binds to Dictyostelium discoideum surface receptors and induces a transient activation of adenylate cyclase, which is followed by desensitization. cAMP also induces a loss of detectable surface receptors (down-regulation). Cells were incubated with constant cAMP concentrations, washed free of

Fluoxetine-induced inhibition of synaptosomal [3H]5-HT release: Possible Ca2+-channel inhibition

International Nuclear Information System (INIS)

Stauderman, K.A.; Gandhi, V.C.; Jones, D.J.

1992-01-01

Fluoxetine, a selective 5-Ht uptake inhibitor, inhibited 15 mM K + -induced [ 3 H]5-HT release from rat spinal cord and cortical synaptosomes at concentrations > 0.5 uM. This effect reflected a property shared by another selective 5-HT uptake inhibitor paroxetine but not by less selective uptake inhibitors such as amitriptyline, desipramine, imipramine or nortriptyline. Inhibition of release by fluoxetine was inversely related to both the concentration of K + used to depolarize the synaptosomes and the concentration of external Ca 2+ . Experiments aimed at determining a mechanism of action revealed that fluoxetine did not inhibit voltage-independent release of [ 3 H]5-HT release induced by the Ca 2+ -ionophore A 23187 or Ca 2+ -independent release induced by fenfluramine. Moreover the 5-HT autoreceptor antagonist methiothepin did not reverse the inhibitory actions of fluoxetine on K + -induced release. Further studies examined the effects of fluoxetine on voltage-dependent Ca 2+ channels and Ca 2+ entry

The effects of estrogen receptors α- and β-specific agonists and antagonists on cell proliferation and energy metabolism in human bone cell line.

Science.gov (United States)

Somjen, D; Katzburg, S; Sharon, O; Grafi-Cohen, M; Knoll, E; Stern, N

2011-02-01

In cultured human osteoblasts estradiol-17β (E2) modulated DNA synthesis, the specific activity of creatine kinase BB (CK), 12 and 15 lipoxygenase (LO) mRNA expression and formation of 12- and 15-hydroxyeicosatetraenoic acid (HETE). We now investigate the response of human bone cell line (SaOS2) to phytoestrogens and estrogen receptors (ER)-specific agonists and antagonists. Treatment of SaSO2 with E2, 2,3-bis (4-hydroxyphenyl)-propionitrile (DPN; ERβ-specific agonist), 4,4',4″-[4-propyl-(1H)-pyrazol-1,3,5-triyl] tris-phenol (PPT; ERα-specific agonist), biochainin A (BA), daidzein (D), genistein (G) and raloxifene (Ral) showed increased DNA synthesis and CK. Ral inhibited completely all stimulations except DPN and to some extent D. The ERα-specific antagonist methyl-piperidino-pyrazole (MPP) and the ERβ-specific antagonist 4-[2-phenyl-5,7-bis (tri-fluoro-methyl) pyrazolo [1,5-a]pyrimidin-3-yl] phenol (PTHPP) inhibited DNA synthesis, CK and reactive oxygen species (ROS) formation induced by estrogens according to their receptors affinity. The LO inhibitor baicaleine inhibited only E2, DPN and G's effects. E2 and Ral unlike all other compounds had no effect on ERα mRNA expression, while ERβ mRNA expression was stimulated by all compounds. All compounds modulated the expression of 12LO and 15LO mRNA, except E2, PPT and Ral for 12LO, and 12- and 15-HETE productions and stimulated ROS formation which was inhibited by NADPH oxidase inhibitors diphenyleneiodonium chloride (DPI) and N-acetyl cysteine and the estrogen inhibitor ICI. DPI did not affect hormonal-induced DNA and CK. In conclusion, we provide evidence for the separation of mediation via ERα and ERβ pathways in the effects of estrogenic compounds on osteoblasts, but the role of LO/HETE/ROS is unclear. Copyright © 2010 Wiley-Liss, Inc.

Saw palmetto extracts potently and noncompetitively inhibit human alpha1-adrenoceptors in vitro.

Science.gov (United States)

Goepel, M; Hecker, U; Krege, S; Rübben, H; Michel, M C

1999-02-15

We wanted to test whether phytotherapeutic agents used in the treatment of lower urinary tract symptoms have alpha1-adrenoceptor antagonistic properties in vitro. Preparations of beta-sitosterol and extracts of stinging nettle, medicinal pumpkin, and saw palmetto were obtained from several pharmaceutical companies. They were tested for their ability to inhibit [3H]tamsulosin binding to human prostatic alpha1-adrenoceptors and [3H]prazosin binding to cloned human alpha1A- and alpha1B-adrenoceptors. Inhibition of phenylephrine-stimulated [3H]inositol phosphate formation by cloned receptors was also investigated. Up to the highest concentration which could be tested, preparations of beta-sitosterol, stinging nettle, and medicinal pumpkin were without consistent inhibitory effect in all assays. In contrast, all tested saw palmetto extracts inhibited radioligand binding to human alpha1-adrenoceptors and agonist-induced [3H]inositol phosphate formation. Saturation binding experiments in the presence of a single saw palmetto extract concentration indicated a noncompetitive antagonism. The relationship between active concentrations in vitro and recommended therapeutic doses for the saw palmetto extracts was slightly lower than that for several chemically defined alpha1-adrenoceptor antagonists. Saw palmetto extracts have alpha1-adrenoceptor-inhibitory properties. If bioavailability and other pharmacokinetic properties of these ingredients are similar to those of the chemically defined alpha1-adrenoceptor antagonists, alpha1-adrenoceptor antagonism might be involved in the therapeutic effects of these extracts in patients with lower urinary tract symptoms suggestive of benign prostatic obstruction.

PERIPUBERTAL PROCHLORAZ EXPOSURE STRONGLY INHIBITS TESTOSTERONE PRODUCTION, BUT HAS WEAK EFFECTS ON PUBERTY

Science.gov (United States)

Prochloraz (PCZ) is an imidazole fungicide that inhibits steroidogenesis and acts as an androgen receptor antagonist. We hypothesized that pubertal exposure to prochloraz would delay preputial separation and development of reproductive organs. Sprague Dawley rats were dosed wit...

Receptor residence time trumps drug-likeness and oral bioavailability in determining efficacy of complement C5a antagonists

Science.gov (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.

2016-04-01

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.

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

Science.gov (United States)

Chen, Ling-Ju; Tsai, Hsiu-Ting; Chen, Wei-Jen; Hsieh, Chu-Yang; Wang, Pi-Chieh; Chen, Chung-Shih; Wang, Lina; Yang, Chi-Chiang

2012-10-01

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 gingivalis in 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, although different 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.

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

Directory of Open Access Journals (Sweden)

Ling-Ju Chen

2012-12-01

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.

ANG II type 1 receptor antagonist irbesartan inhibits coronary angiogenesis stimulated by chronic intermittent hypoxia in neonatal rats

Czech Academy of Sciences Publication Activity Database

Rakusan, K.; Chvojková, Zuzana; Oliviero, P.; Ošťádalová, Ivana; Kolář, František; Chassagne, C.; Samuel, J. L.; Ošťádal, Bohuslav

2007-01-01

Roč. 292, č. 3 (2007), H1237-H1244 ISSN 0363-6135 R&D Projects: GA MŠk 1M0510 Institutional research plan: CEZ:AV0Z50110509 Keywords : angiogenesis neonatal rat * ANG II type 1 receptor antagonist heart * ischemic tolerance Subject RIV: ED - Physiology Impact factor: 3.973, year: 2007

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

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Stephen R Morairty

2014-01-01

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

Inhibition of B16-BL6 melanoma growth in mice by methionine-enkephalin.

Science.gov (United States)

Murgo, A J

1985-08-01

The antitumor effect of methionine-enkephalin [( Met]enkephalin) was demonstrated in C57BL/6J mice inoculated with B16-BL6 melanoma cells. Local subcutaneous tumor growth was inhibited with a 50-micrograms dose daily for 7 or 14 days. The antitumor effect of [Met]enkephalin was inhibited by the administration of the opioid receptor antagonist naloxone. Naloxone alone had no significant effect on tumor growth.

AT-406, an orally active antagonist of multiple inhibitor of apoptosis proteins, inhibits progression of human ovarian cancer.

Science.gov (United States)

Brunckhorst, Melissa K; Lerner, Dimitry; Wang, Shaomeng; Yu, Qin

2012-07-01

Ovarian carcinoma is the most deadly gynecological malignancy. Current chemotherapeutic drugs are only transiently effective and patients with advance disease often develop resistance despite significant initial responses. Mounting evidence suggests that anti-apoptotic proteins, including those of the inhibitor of apoptosis protein (IAP) family, play important roles in the chemoresistance. There has been a recent emergence of compounds that block the IAP functions. Here, we evaluated AT-406, a novel and orally active antagonist of multiple IAP proteins, in ovarian cancer cells as a single agent and in the combination with carboplatin for therapeutic efficacy and mechanism of action. We demonstrate that AT-406 has significant single agent activity in 60% of human ovarian cancer cell lines examined in vitro and inhibits ovarian cancer progression in vivo and that 3 out of 5 carboplatin-resistant cell lines are sensitive to AT-406, highlighting the therapeutic potential of AT-406 for patients with inherent or acquired platinum resistance. Additionally, our in vivo studies show that AT-406 enhances the carboplatin-induced ovarian cancer cell death and increases survival of the experimental mice, suggesting that AT-406 sensitizes the response of these cells to carboplatin. Mechanistically, we demonstrate that AT-406 induced apoptosis is correlated with its ability to down-regulate XIAP whereas AT-406 induces cIAP1 degradation in both AT-406 sensitive and resistance cell lines. Together, these results demonstrate, for the first time, the anti-ovarian cancer efficacy of AT-406 as a single agent and in the combination with carboplatin, suggesting that AT-406 has potential as a novel therapy for ovarian cancer patients, especially for patients exhibiting resistance to the platinum-based therapies.

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.

Adenyl cyclases and cAMP in plant signaling - Past and present

KAUST Repository

Gehring, Christoph A.

2010-06-25

In lower eukaryotes and animals 3\\'-5\\'-cyclic adenosine monophosphate (cAMP) and adenyl cyclases (ACs), enzymes that catalyse the formation of cAMP from ATP, have long been established as key components and second messengers in many signaling pathways. In contrast, in plants, both the presence and biological role of cAMP have been a matter of ongoing debate and some controversy. Here we shall focus firstly on the discovery of cellular cAMP in plants and evidence for a role of this second messenger in plant signal transduction. Secondly, we shall review current evidence of plant ACs, analyse aspects of their domain organisations and the biological roles of candidate molecules. In addition, we shall assess different approaches based on search motifs consisting of functionally assigned amino acids in the catalytic centre of annotated and/or experimentally tested nucleotide cyclases that can contribute to the identification of novel candidate molecules with AC activity such as F-box and TIR proteins. 2010 Gehring; licensee BioMed Central Ltd.

Adenyl cyclase activator forskolin protects against Huntington's disease-like neurodegenerative disorders

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Sidharth Mehan

2017-01-01

Full Text Available Long term suppression of succinate dehydrogenase by selective inhibitor 3-nitropropionic acid has been used in rodents to model Huntington's disease where mitochondrial dysfunction and oxidative damages are primary pathological hallmarks for neuronal damage. Improvements in learning and memory abilities, recovery of energy levels, and reduction of excitotoxicity damage can be achieved through activation of Adenyl cyclase enzyme by a specific phytochemical forskolin. In this study, intraperitoneal administration of 10 mg/kg 3-nitropropionic acid for 15 days in rats notably reduced body weight, worsened motor cocordination (grip strength, beam crossing task, locomotor activity, resulted in learning and memory deficits, greatly increased acetylcholinesterase, lactate dehydrogenase, nitrite, and malondialdehyde levels, obviously decreased adenosine triphosphate, succinate dehydrogenase, superoxide dismutase, catalase, and reduced glutathione levels in the striatum, cortex and hippocampus. Intragastric administration of forskolin at 10, 20, 30 mg/kg dose-dependently reversed these behavioral, biochemical and pathological changes caused by 3-nitropropionic acid. These results suggest that forskolin exhibits neuroprotective effects on 3-nitropropionic acid-induced Huntington's disease-like neurodegeneration.

Adenyl cyclases and cAMP in plant signaling - Past and present

KAUST Repository

Gehring, Christoph A

2010-01-01

In lower eukaryotes and animals 3'-5'-cyclic adenosine monophosphate (cAMP) and adenyl cyclases (ACs), enzymes that catalyse the formation of cAMP from ATP, have long been established as key components and second messengers in many signaling pathways. In contrast, in plants, both the presence and biological role of cAMP have been a matter of ongoing debate and some controversy. Here we shall focus firstly on the discovery of cellular cAMP in plants and evidence for a role of this second messenger in plant signal transduction. Secondly, we shall review current evidence of plant ACs, analyse aspects of their domain organisations and the biological roles of candidate molecules. In addition, we shall assess different approaches based on search motifs consisting of functionally assigned amino acids in the catalytic centre of annotated and/or experimentally tested nucleotide cyclases that can contribute to the identification of novel candidate molecules with AC activity such as F-box and TIR proteins. 2010 Gehring; licensee BioMed Central Ltd.

Tonic inhibition by orphanin FQ/nociceptin of noradrenaline neurotransmission in the amygdala

NARCIS (Netherlands)

Kawahara, Y; Hesselink, M.B.; van Scharrenburg, G; Westerink, B.H.C.

2004-01-01

The present microdialysis study investigated whether nociceptin/orphanin FQ exerts a tonic inhibition of the release of noradrenaline in the basolateral nucleus of the amygdala in awake rats. The non-peptide competitive nociceptin/orphanin FQ (N/OFQ) peptide receptor antagonist J-113397 (20 mg/kg

Voluntary activation of ankle muscles is accompanied by subcortical facilitation of their antagonists

DEFF Research Database (Denmark)

Geertsen, Svend S.; Zuur, Abraham Theodoor; Nielsen, Jens B.

2010-01-01

Flexion and extension movements are organized reciprocally, so that extensor motoneurones in the spinal cord are inhibited when flexor muscles are active and vice versa. During and just prior to dorsiflexion of the ankle, soleus motoneurones are thus inhibited as evidenced by a depression......) or soleus muscle of the left ankle. TMS was applied to the hotspot of TA and soleus muscles on separate days. Stimuli were delivered prior to and at the beginning of contraction. Soleus MEPs were significantly facilitated when TMS was applied 50 ms prior to onset of plantar flexion. Surprisingly, soleus...... was increased prior to plantar flexion, but not prior to dorsiflexion. These findings suggest that voluntary contraction at the ankle is accompanied by preceding facilitation of antagonists by a subcortical motor programme. This may help to ensure that the direction of movement may be changed quickly...

Slow receptor dissociation kinetics differentiate macitentan from other endothelin receptor antagonists in pulmonary arterial smooth muscle cells.

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John Gatfield

Full Text Available Two endothelin receptor antagonists (ERAs, bosentan and ambrisentan, are currently approved for the treatment of pulmonary arterial hypertension (PAH, a devastating disease involving an activated endothelin system and aberrant contraction and proliferation of pulmonary arterial smooth muscle cells (PASMC. The novel ERA macitentan has recently concluded testing in a Phase III morbidity/mortality clinical trial in PAH patients. Since the association and dissociation rates of G protein-coupled receptor antagonists can influence their pharmacological activity in vivo, we used human PASMC to characterize inhibitory potency and receptor inhibition kinetics of macitentan, ambrisentan and bosentan using calcium release and inositol-1-phosphate (IP(1 assays. In calcium release assays macitentan, ambrisentan and bosentan were highly potent ERAs with K(b values of 0.14 nM, 0.12 nM and 1.1 nM, respectively. Macitentan, but not ambrisentan and bosentan, displayed slow apparent receptor association kinetics as evidenced by increased antagonistic potency upon prolongation of antagonist pre-incubation times. In compound washout experiments, macitentan displayed a significantly lower receptor dissociation rate and longer receptor occupancy half-life (ROt(1/2 compared to bosentan and ambrisentan (ROt(1/2:17 minutes versus 70 seconds and 40 seconds, respectively. Because of its lower dissociation rate macitentan behaved as an insurmountable antagonist in calcium release and IP(1 assays, and unlike bosentan and ambrisentan it blocked endothelin receptor activation across a wide range of endothelin-1 (ET-1 concentrations. However, prolongation of the ET-1 stimulation time beyond ROt(1/2 rendered macitentan a surmountable antagonist, revealing its competitive binding mode. Bosentan and ambrisentan behaved as surmountable antagonists irrespective of the assay duration and they lacked inhibitory activity at high ET-1 concentrations. Thus, macitentan is a competitive

Acute D3 Antagonist GSK598809 Selectively Enhances Neural Response During Monetary Reward Anticipation in Drug and Alcohol Dependence

Science.gov (United States)

Murphy, Anna; Nestor, Liam J; McGonigle, John; Paterson, Louise; Boyapati, Venkataramana; Ersche, Karen D; Flechais, Remy; Kuchibatla, Shankar; Metastasio, Antonio; Orban, Csaba; Passetti, Filippo; Reed, Laurence; Smith, Dana; Suckling, John; Taylor, Eleanor; Robbins, Trevor W; Lingford-Hughes, Anne; Nutt, David J; Deakin, John FW; Elliott, Rebecca

2017-01-01

Evidence suggests that disturbances in neurobiological mechanisms of reward and inhibitory control maintain addiction and provoke relapse during abstinence. Abnormalities within the dopamine system may contribute to these disturbances and pharmacologically targeting the D3 dopamine receptor (DRD3) is therefore of significant clinical interest. We used functional magnetic resonance imaging to investigate the acute effects of the DRD3 antagonist GSK598809 on anticipatory reward processing, using the monetary incentive delay task (MIDT), and response inhibition using the Go/No-Go task (GNGT). A double-blind, placebo-controlled, crossover design approach was used in abstinent alcohol dependent, abstinent poly-drug dependent and healthy control volunteers. For the MIDT, there was evidence of blunted ventral striatal response to reward in the poly-drug-dependent group under placebo. GSK598809 normalized ventral striatal reward response and enhanced response in the DRD3-rich regions of the ventral pallidum and substantia nigra. Exploratory investigations suggested that the effects of GSK598809 were mainly driven by those with primary dependence on alcohol but not on opiates. Taken together, these findings suggest that GSK598809 may remediate reward deficits in substance dependence. For the GNGT, enhanced response in the inferior frontal cortex of the poly-drug group was found. However, there were no effects of GSK598809 on the neural network underlying response inhibition nor were there any behavioral drug effects on response inhibition. GSK598809 modulated the neural network underlying reward anticipation but not response inhibition, suggesting that DRD3 antagonists may restore reward deficits in addiction. PMID:28042871

Pertussis toxin treatment does not block inhibition by atrial natriuretic factor of aldosterone secretion in cultured bovine zona glomerulosa cells

International Nuclear Information System (INIS)

De Lean, A.; Cantin, M.

1986-01-01

The authors have previously reported that atrial natriuretic factor (ANF) potently inhibits PGE or forskolin-stimulation aldosterone secretion in bovine zona glomerulosa (ZG) by acting through specific high affinity receptors. In order to evaluate the functional role of the regulatory protein N/sub i/ and the inhibition of adenylate cyclase activity (AC) in ZG, the authors have studied the effect of treatment with PT on inhibition by ANF of aldosterone production. Primary cultures of ZG were treated for 18 hours in serum-free F12 medium with (0-100 ng/ml PT). No effect of PT pretreatment was observed either on basal, PGE-stimulated or ANF-inhibited levels of steroidogenesis. When membranes prepared from control ZG were ADP-ribosylated with [ 32 P] NAD in the presence of PT, two toxin-specific bands with 39 Kd and 41 Kd were documented on SDS gel. Cell pretreatment with as low as 1 ng/ml drastically reduced further labelling of these two bands while higher doses completely abolished them. Since PT treatment covalently modifies completely the toxin substrate without altering ANF inhibition of adrenal steroidogenesis, the authors conclude that N/sub i/ is not involved in the mode of action of ANF on aldosterone production

Isolation and characterization of actinomycete antagonists of a fungal root pathogen.

Science.gov (United States)

Crawford, D L; Lynch, J M; Whipps, J M; Ousley, M A

1993-11-01

By use of selective media, 267 actinomycete strains were isolated from four rhizosphere-associated and four non-rhizosphere-associated British soils. Organic media with low nutrient concentrations were found to be best for isolating diverse actinomycetes while avoiding contamination and overgrowth of isolation media by eubacteria and fungi. While all isolates grew well at pHs 6.5 to 8.0, a few were unable to grow at pH 6.0 and a significant number failed to grow at pH 5.5. Eighty-two selected isolates were screened for in vitro antagonism towards Pythium ultimum by use of a Difco cornmeal agar assay procedure. Five isolates were very strong antagonists of the fungus, four were strong antagonists, and ten others were weakly antagonistic. The remaining isolates showed no antagonism by this assay. Additional studies showed that several of the P. ultimum antagonists also strongly inhibited growth of other root-pathogenic fungi. Twelve isolates showing antifungal activity in the in vitro assay were also tested for their effects on the germination and short-term growth of lettuce plants in glasshouse pot studies in the absence of pathogens. None of the actinomycetes prevented seed germination, although half of the isolates retarded seed germination and outgrowth of the plants by 1 to 3 days. During 18-day growth experiments, biomass yields of some actinomycete-inoculated plants were reduced in comparison with untreated control plants, although all plants appeared healthy and well rooted. None of the actinomycetes significantly enhanced plant growth over these short-term experiments. For some, but not all, actinomycetes, some correlations between delayed seed germination and reduced 18-day plant biomass yields were seen. For others, plant biomass yields were not reduced despite an actinomycete-associated delay in seed germination and plant outgrowth. Preliminary glasshouse experiments indicated that some of the actinomycetes protect germinating lettuce seeds against

Functional and biochemical responses of cultured heart cells to angiotensin II

International Nuclear Information System (INIS)

Allen, I.; Gaa, S.; Rogers, T.B.

1986-01-01

The authors have utilized a cultured neonatal rat heart myocyte system to study the molecular mechanisms involved in the stimulation of heart cells by angiotensin II (AII). The intact cultured cells, and membranes from these cells, have specific, high affinity receptors for 125 I-AII and for an AII antagonist, 125 I-Sar 1 ,Leu 8 -AII. Binding affinity was in the nanomolar range and was inhibited by guanine nucleotides. Functional studies on intact, beating cells revealed a maximal increase in contractile frequency of 50%, observed at 5 nM AII, with half maximal effects noted at around 1 nM. These responses were reversible and specific as the antagonist, Sar 1 , Ala 8 -AII, inhibited AII-induced chronotropic stimulation. AII (100 nM) had no effect on basal adenylate cyclase activity (20 pmoles cAMP/mg prot/min at 2.5mM Mg 2+ ) in cell membranes. Further, in membranes where cyclase activity was stimulated with isoproterenol (290 pmoles cAMP/mg prot/min at 2.5mM Mg 2+ ), addition of AII had no effect. The cyclase-inhibitory muscarinic agonist, carbachol, also failed to reduce isoproterenol-stimulated activity. In preliminary work with the intact cells, AII again did not alter basal cAMP levels (3-10 pmoles cAMP/mg prot). However, the hormone increased isoproterenol-stimulated cAMP levels by almost 50%. These cells are an excellent system for correlating AII receptor binding with functional and biochemical responses

Inhibition of A2A Adenosine Receptor Signaling in Cancer Cells Proliferation by the Novel Antagonist TP455

Directory of Open Access Journals (Sweden)

Stefania Gessi

2017-12-01

Full Text Available Several evidences indicate that the ubiquitous nucleoside adenosine, acting through A1, A2A, A2B, and A3 receptor (AR subtypes, plays crucial roles in tumor development. Adenosine has contrasting effects on cell proliferation depending on the engagement of different receptor subtypes in various tumors. The involvement of A2AARs in human A375 melanoma, as well as in human A549 lung and rat MRMT1 breast carcinoma proliferation has been evaluated in view of the availability of a novel A2AAR antagonist, with high affinity and selectivity, named as 2-(2-furanyl-N5-(2-methoxybenzyl[1,3]thiazolo[5,4-d]pyrimidine-5,7-diammine (TP455. Specifically, the signaling pathways triggered in the cancer cells of different origin and the antagonist effect of TP455 were investigated. The A2AAR protein expression was evaluated through receptor binding assays. Furthermore, the effect of A2AAR activation on cell proliferation at 24, 48 and 72 hours was studied. The selective A2AAR agonist 2-p-(2-carboxyethylphenethylamino-5′-N-ethylcarboxamidoadenosine hydrochloride (CGS21680, concentration-dependently induced cell proliferation in A375, A549, and MRMT1 cancer cells and the effect was potently antagonized by the A2AAR antagonist TP455, as well as by the reference A2AAR blocker 4-(2-[7-amino-2-(2-furyl[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethylphenol (ZM241385. As for the signaling pathway recruited in this response we demonstrated that, by using the specific inhibitors of signal transduction pathways, the effect of A2AAR stimulation was induced through phospholipase C (PLC and protein kinase C-delta (PKC-δ. In addition, we evaluated, through the AlphaScreen SureFire phospho(p protein assay, the kinases enrolled by A2AAR to stimulate cell proliferation and we found the involvement of protein kinase B (AKT, extracellular regulated kinases (ERK1/2, and c-Jun N-terminal kinases (JNKs. Indeed, we demonstrated that the CGS21680 stimulatory effect on kinases was

Synergy between an antiangiogenic integrin αv antagonist and an antibody–cytokine fusion protein eradicates spontaneous tumor metastases

OpenAIRE

Lode, Holger N.; Moehler, Thomas; Xiang, Rong; Jonczyk, Alfred; Gillies, Stephen D.; Cheresh, David A.; Reisfeld, Ralph A.

1999-01-01

The suppression and eradication of primary tumors and distant metastases is a major goal of alternative treatment strategies for cancer, such as inhibition of angiogenesis and targeted immunotherapy. We report here a synergy between two novel monotherapies directed against vascular and tumor compartments, respectively, a tumor vasculature-specific antiangiogenic integrin αv antagonist and tumor-specific antibody–interleukin 2 (IL-2) fusion proteins. Simultaneous an...

Mechanism of A2 adenosine receptor activation. I. Blockade of A2 adenosine receptors by photoaffinity labeling

International Nuclear Information System (INIS)

Lohse, M.J.; Klotz, K.N.; Schwabe, U.

1991-01-01

It has previously been shown that covalent incorporation of the photoreactive adenosine derivative (R)-2-azido-N6-p-hydroxy-phenylisopropyladenosine [(R)-AHPIA] into the A1 adenosine receptor of intact fat cells leads to a persistent activation of this receptor, resulting in a reduction of cellular cAMP levels. In contrast, covalent incorporation of (R)-AHPIA into human platelet membranes, which contain only stimulatory A2 adenosine receptors, reduces adenylate cyclase stimulation via these receptors. This effect of (R)-AHPIA is specific for the A2 receptor and can be prevented by the adenosine receptor antagonist theophylline. Binding studies indicate that up to 90% of A2 receptors can be blocked by photoincorporation of (R)-AHPIA. However, the remaining 10-20% of A2 receptors are sufficient to mediate an adenylate cyclase stimulation of up to 50% of the control value. Similarly, the activation via these 10-20% of receptors occurs with a half-life that is only 2 times longer than that in control membranes. This indicates the presence of a receptor reserve, with respect to both the extent and the rate of adenylate cyclase stimulation. These observations require a modification of the models of receptor-adenylate cyclase coupling

Benzazepines: Structure-activity relationships between D1 receptor blockade and selected pharmacological effects

International Nuclear Information System (INIS)

Iorio, L.C.; Billiard, W.; Gold, E.H.

1986-01-01

This chapter describes the displacement of 3 H-23390 and 3 H-spiperone binding by dopamine agonists and antagonists. The authors undertook an evaluation of the ability of selected analogs of SCH 23390 to displace 3 H-SCH 23390 and 3 H-spiperone. Structure-activity relationships of SCH 23390 analogs: 7-position substituents, is shown. It is shown that, in general, benzazepines with a variety of substituents in the 7-position retain their selectivity for D 1 sites. Substituents at the 8-position and at the N-position are also discussed. The authors determine a correlation between displacement of 3 H-SCH 23390 and blockade of dopamine-sensitive adenylate cyclase (DSAC). These effects and inhibition of conditioned avoidance responsing (CAS) in rats was also studied. A detailed evaluation is presented of the effects of SCH 23390 and haloperidol in the Inclined Screen and CAR tests

GLP-1 receptor antagonist as a potential probe for pancreatic β-cell imaging

International Nuclear Information System (INIS)

Mukai, Eri; Toyoda, Kentaro; Kimura, Hiroyuki; Kawashima, Hidekazu; Fujimoto, Hiroyuki; Ueda, Masashi; Temma, Takashi; Hirao, Konomu; Nagakawa, Kenji; Saji, Hideo; Inagaki, Nobuya

2009-01-01

We examined exendin(9-39), an antagonist of glucagon-like peptide-1 (GLP-1) receptor (GLP-1R), as a potential probe for imaging of pancreatic β-cells. To evaluate in vitro receptor specificity, binding assay was performed using dispersed mouse islet cells. Binding assay showed competitive inhibition of [ 125 I]BH-exendin(9-39) binding by non-radioactive exendin(9-39). To assess in vivo selectivity, the biodistribution was evaluated by intravenous administration of [ 125 I]BH-exendin(9-39) to mice. Radioactivity of harvested pancreas reached highest levels at 60 and 120 min among organs examined except lung. Pre-administration of excess non-radioactive exendin(9-39) remarkably and specifically blocked the radioactivity of pancreas. After [ 125 I]BH-exendin(9-39) injection into transgenic mice with pancreatic β-cells expressing GFP, fluorescent and radioactive signals of sections of pancreas were evaluated with an image analyzer. Imaging analysis showed that the fluorescent GFP signals and the radioactive signals were correspondingly located. Thus, the GLP-1R antagonist exendin(9-39) may serve as a useful probe for pancreatic β-cell imaging.

Effects of catecholamines on rat myocardial metabolism. II. Influence of catecholamines on 32p-incorporation into rat myocardial adenylic nucleotides and their turn-over.

Science.gov (United States)

Merouze, P; Gaudemer, Y; Gautheron, D

1975-01-01

1. The influence of catecholamines (adrenaline and noradrenaline) on 32Pi incorporation into intracellular phosphate and adenylic nucleotides has been studied on rat myocardium slices; consequently, the turn-over of nucleotides could be determined and compared under the influence of these two hormones. 2. In order to specify the site of action of these catecholamines, several inhibitors and activators of energetic metabolism were included in the incubation medium: 3'5'-AMP, caffein, ouabain, oligomycin, rotenone + antimycin. 3. Both catecholamines favour Pi exchanges between intra and extracellular spaces; ATP turn-over is greatly increased, while ADP turn-over is slightly decreased, and 32P-incorporation into ADP is increased. 4. 3'5'-AMP and caffein are without effect on Pi penetration; however, caffein increases catecholamine effects on this penetration. ATP turn-over is slightly increased by 3'5'-AMP or caffein. 5. Ouabain decreases ATP turn-over but does not prevent the adrenaline induced acceleration. Inhibitors of oxidative phosphorylation and electron transport decrease ATP-turn-over severely; this inhibition is not released by catecholamines. 6. It is concluded that the catecholamine effects observed are dependent on the oxidative phosphorylations process. The increase of Pi exchange by catecholamines may be related to the increase of extracellular space and cation translocations we observed with the hormones.

Pressure stabilization is not a general property of thermophilic enzymes: the adenylate kinases of Methanococcus voltae, Methanococcus maripaludis, Methanococcus thermolithotrophicus, and Methanococcus jannaschii.

OpenAIRE

Konisky, J; Michels, P C; Clark, D S

1995-01-01

The application of 50-MPa pressure did not increase the thermostabilities of adenylate kinases purified from four related mesophilic and thermophilic marine methanogens. Thus, while it has been reported that some thermophilic enzymes are stabilized by pressure (D. J. Hei and D. S. Clark, Appl. Environ. Microbiol. 60:932-939, 1994), hyperbaric stabilization is not an intrinsic property of all enzymes from deep-sea thermophiles.

Acute anal stretch inhibits NMDA-dependent pelvic-urethra reflex potentiation via spinal GABAergic inhibition in anesthetized rats.

Science.gov (United States)

Chen, Sung-Lang; Huang, Yu-Hui; Kao, Yu-Lin; Chen, Gin-Den; Cheng, Chen-Li; Peng, Hsien-Yu; Liao, Jiuan-Miaw; Huang, Pei-Chen; Tsai, Shih-Jei; Lin, Tzer-Bin

2008-10-01

The impact of acute anal stretch on the pelvic-urethra reflex potentiation was examined in urethane-anesthetized rats by recording the external urethra sphincter electromyogram activity evoked by the pelvic afferent stimulation. Test stimulation (1 stimulation/30 s) evoked a baseline reflex activity with a single action potential that was abolished by gallamine (5 mg/kg iv). On the other hand, the repetitive stimulation (1 stimulation/1 s) induced spinal reflex potentiation (SRP) that was attenuated by intrathecal 6-cyano-7-nitroquinoxaline-2,4-dione (a glutamatergic alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionat receptor antagonist, 100 microM, 10 microl) and d-2-amino-5-phosphonovalerate [a glutamatergic N-methyl-D-aspartate (NMDA) antagonist, 100 microM, 10 microl]. Acute anal stretch using a mosquito clamp with a distance of 4 mm exhibited no effect, whereas distances of 8 mm attenuated and 12 mm abolished the repetitive stimulation-induced SRP. Intrathecal NMDA (100 microM, 10 microl) reversed the abolition on SRP caused by anal stretch. On the other hand, pretreated bicuculline [gamma-aminobutyric acid (GABA) A receptor antagonist, 100 microM, 10 microl] but not hydroxysaclofen (GABAB receptor antagonist) counteracted the abolition on the repetitive stimulation-induced SRP caused by the anal stretch. All of the results suggested that anal stretch may be used as an adjunct to assist voiding dysfunction in patients with overactive urethra sphincter and that GABAergic neurotransmission is important in the neural mechanisms underlying external urethra sphincter activity inhibited by anal stretch.

Evaluation of biological activities of new LH-RH antagonists (T-series) in male and female rats.

Science.gov (United States)

Pinski, J; Yano, T; Janaky, T; Nagy, A; Juhasz, A; Bokser, L; Groot, K; Schally, A V

1993-01-01

A series of new highly potent LH-RH antagonists (T-series) has been synthesized in our laboratory. Among these analogs, antagonists [Ac-D-Nal(2), D-Phe(4Cl)2, D-Pal(3)3, D-Lys(A2pr(Car)2)6, D-Ala10]LH-RH (T-140); [Ac-D-Nal(2)1, D-Phe(4Cl)2, D-Pal(3)3, D-Lys(A2pr(Ac)2)6, D-Ala10]LH-RH (T-148); [Ac-D-Nal(2)1, D-Phe(4Cl)2, D-Pal(3)3, D-Lys(A2pr(For)2)6, D-Ala10]LH-RH (T-151) and [Ac-D-Nal(2)1, D-Phe(4Cl)2, D-Pal(3)3, D-Lys(A2bu(For)2)6, D-Ala10]LH-RH (T-159) were the most powerful. Antagonists T-140, T-148 and T-151 produced a complete blockade of ovulation in normal cycling rats at a dose of 1.5 micrograms/rat and antagonist T-159 at a dose of only 0.75 micrograms/rat. The inhibitory effects of compounds T-148, T-151 and T-159 on gonadotropin and sex steroid secretion were investigated in male and female rats. To determine their effect on LH levels in castrated male and ovariectomized female rats, T-148, T-151 and T-159 were injected subcutaneously in doses of 0.625 and 2.5 micrograms/rat. Blood samples were taken at different intervals for 48 h. All three compounds at either dose caused a significant (P < 0.01) decrease in LH levels for more than 6 h. Significant (P < 0.01) inhibition of LH lasted for more than 24 h following a dose of 2.5 micrograms sc of all 3 antagonists in both male and female rats. Serum FSH levels were also suppressed significantly for more than 48 h in castrated male rats by all three antagonists at a dose of 5 micrograms/rat sc.(ABSTRACT TRUNCATED AT 250 WORDS)

The oxytocin/vasopressin receptor antagonist atosiban delays the gastric emptying of a semisolid meal compared to saline in human

Directory of Open Access Journals (Sweden)

Ekberg Olle

2006-03-01

Full Text Available Abstract Background Oxytocin is released in response to a meal. Further, mRNA for oxytocin and its receptor have been found throughout the gastrointestinal (GI tract. The aim of this study was therefore to examine whether oxytocin, or the receptor antagonist atosiban, influence the gastric emptying. Methods Ten healthy volunteers (five men were examined regarding gastric emptying at three different occasions: once during oxytocin stimulation using a pharmacological dose; once during blockage of the oxytocin receptors (which also blocks the vasopressin receptors and thereby inhibiting physiological doses of oxytocin; and once during saline infusion. Gastric emptying rate (GER was assessed and expressed as the percentage reduction in antral cross-sectional area from 15 to 90 min after ingestion of rice pudding. The assessment was performed by real-time ultrasonography. At the same time, the feeling of satiety was registered using visual satiety scores. Results Inhibition of the binding of endogenous oxytocin by the receptor antagonist delayed the GER by 37 % compared to saline (p = 0.037. In contrast, infusion of oxytocin in a dosage of 40 mU/min did not affect the GER (p = 0.610. Satiation scores areas in healthy subjects after receiving atosiban or oxytocin did not show any significant differences. Conclusion Oxytocin and/or vasopressin seem to be regulators of gastric emptying during physiological conditions, since the receptor antagonist atosiban delayed the GER. However, the actual pharmacological dose of oxytocin in this study had no effect. The effect of oxytocin and vasopressin on GI motility has to be further evaluated.

Characteristics of the binding of [3H]nitrendipine to rabbit ventricular membranes: modification by other Ca++ channel antagonists and by the Ca++ channel agonist Bay K 8644

International Nuclear Information System (INIS)

Janis, R.A.; Sarmiento, J.G.; Maurer, S.C.; Bolger, G.T.; Triggle, D.J.

1984-01-01

This study was carried out to characterize [ 3 H]nitrendipine binding to cardiac membranes and to test the hypothesis that high affinity binding of Ca++ channel antagonists and agonists is to Ca++ channels. Binding was specific, rapid, reversible and stereoselective. The relative order of potency of nifedipine analogs for inhibition of binding was the same as that for inhibition of smooth and cardiac muscle contraction. Results with diltiazem, verapamil and lidoflazine were consistent with the hypothesis that nondihydropyridine Ca++ channel antagonists act at one or more sites allosterically linked to the 1,4-dihydropyridine site in cardiac cells. The Ca++ channel agonist Bay K 8644 [methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine- 5-carboxylate] displaced specifically bound [ 3 H]nitrendipine in an apparently competitive manner with an IC50 value of 5 nM. The results suggest that organic antagonists do not act by physically blocking the Ca++ channel. The data also support the hypothesis that the high affinity binding sites for [ 3 H]nitrendipine in isolated cardiac membranes are associated with Ca++ channels that are inactivated or are otherwise unavailable for opening

Nogo-66 receptor antagonist peptide (NEP1-40) administration promotes functional recovery and axonal growth after lateral funiculus injury in the adult rat

NARCIS (Netherlands)

Cao, Y.; Shumsky, J. S.; Sabol, M. A.; Kushner, R. A.; Strittmatter, S.; Hamers, F. P. T.; Lee, D. H. S.; Rabacchi, S. A.; Murray, M.

2008-01-01

Objective. The myelin protein Nogo inhibits axon regeneration by binding to its receptor (NgR) on axons. Intrathecal delivery of an NgR antagonist (NEP1-40) promotes growth of injured corticospinal axons and recovery of motor function following a dorsal hemisection. The authors used a similar design

Pharmacological analysis of the inhibition produced by moxonidine and agmatine on the vasodepressor sensory CGRPergic outflow in pithed rats.

Science.gov (United States)

Rubio-Beltrán, Eloísa; Labastida-Ramírez, Alejandro; Hernández-Abreu, Oswaldo; MaassenVanDenBrink, Antoinette; Villalón, Carlos M

2017-10-05

Calcitonin gene-related peptide (CGRP) plays a role in several (patho)physiological functions, and modulation of its release is considered a therapeutic target. In this respect, electrical spinal (T 9 --T 12 ) stimulation of the perivascular sensory outflow in pithed rats produces vasodepressor responses mediated by CGRP release. This study investigated the role of imidazoline I 1 and I 2 receptors in the inhibition by moxonidine and agmatine of these vasodepressor responses. Male Wistar pithed rats (pretreated i.v. with 25mg/kg gallamine and 2mg/kg⋅min hexamethonium) received i.v. continuous infusions of methoxamine (20μg/kg⋅min) followed by physiological saline (0.02ml/min), moxonidine (1, 3, 10 or 30μg/kg⋅min) or agmatine (1000 or 3000μg/kg⋅min). Under these conditions, electrical stimulation (0.56-5.6Hz; 50V; 2ms) of the spinal cord (T 9 -T 12 ) produced frequency-dependent vasodepressor responses which were: (i) unchanged during saline infusion; and (ii) inhibited during the above infusions of moxonidine or agmatine. Moreover, using i.v. administrations, the inhibition by 3μg/kg⋅min moxonidine or 3000μg/kg⋅min agmatine (which failed to inhibit the vasodepressor responses by α-CGRP; 0.1-1µg/kg) was: (i) unaltered after saline (1ml/kg), rauwolscine (300μg/kg; α 2 -adrenoceptor antagonist) or BU224 (300μg/kg; imidazoline I 2 receptor antagonist); and (ii) reversed after AGN 192403 (3000μg/kg; imidazoline I 1 receptor antagonist). This reversion was relatively more pronounced after AGN 192403 plus rauwolscine. These blocking doses of antagonists lacked any effects on the electrically-induced vasodepressor responses. Therefore, the inhibition of the vasodepressor sensory CGRPergic outflow by moxonidine and agmatine is mainly mediated by prejunctional imidazoline I 1 receptors on perivascular sensory nerves. Copyright © 2017 Elsevier B.V. All rights reserved.

Adverse cutaneous reactions induced by TNF-alpha antagonist therapy.

Science.gov (United States)

Borrás-Blasco, Joaquín; Navarro-Ruiz, Andrés; Borrás, Consuelo; Casterá, Elvira

2009-11-01

To review adverse cutaneous drug reactions induced by tumor necrosis factor alpha (TNF-alpha) antagonist therapy. A literature search was performed using PubMed (1996-March 2009), EMBASE, and selected MEDLINE Ovid bibliography searches. All language clinical trial data, case reports, letters, and review articles identified from the data sources were used. Since the introduction of TNF-alpha antagonist, the incidence of adverse cutaneous drug reactions has increased significantly. A wide range of different skin lesions might occur during TNF-alpha antagonist treatment. New onset or exacerbation of psoriasis has been reported in patients treated with TNF-alpha antagonists for a variety of rheumatologic conditions. TNF-alpha antagonist therapy has been associated with a lupus-like syndrome; most of these case reports occurred in patients receiving either etanercept or infliximab. Serious skin reactions such as erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis have been reported rarely with the use of TNF-alpha antagonists. As the use of TNF-alpha antagonists continues to increase, the diagnosis and management of cutaneous side effects will become an increasingly important challenge. In patients receiving TNF-alpha antagonist treatment, skin disease should be considered, and clinicians need to be aware of the adverse reactions of these drugs.

Structure of CC chemokine receptor 2 with orthosteric and allosteric antagonists

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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)

2016-12-07

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 http://www.clinicaltrials.gov) 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.

Vascular mechanism of action of endothelin-1: Effect of Ca2+ antagonists

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Chabrier, P.E.; Auguet, M.; Roubert, P.; Lonchampt, M.O.; Gillard, V.; Guillon, J.M.; Delaflotte, S.; Braquet, P.

1989-01-01

The vasoconstrictive properties of the endothelium-derived peptide, endothelin-1 (ET-1), were investigated on rat isolated aorta and on cultured rat aortic smooth muscle cells. In rat isolated aorta, endothelin-1 induced a slow and sustained contraction in a Ca2+-free medium; after calcium readmission, an additional sustained contraction was elicited. In vascular smooth muscle cells, endothelin-1 provoked a dose-dependent Ca2+ influx that was not inhibited by calcium entry blockers (nifedipine, D 600, or diltiazem). In these cells, [ 125 I]-endothelin-1 bound to a specific, saturable, and high affinity recognition site (Kd about 10(-9) M and Bmax = 52 +/- 2 fmol/10(6) cells). The binding was not reversible and not affected by calcium antagonists. These data do not support the hypothesis that endothelin-1 acts as an endogenous agonist of the voltage-dependent Ca2+ channels. The action of endothelin-1 can be separated into two components: one dependent on Ca2+ influx but insensitive to calcium antagonists and another independent of extracellular Ca2+. The irreversible binding of endothelin-1 may reflect an internalization of the ligand inside the cell membrane, leading to multiple contractile events

Distribution and protective function of pituitary adenylate cyclase-activating polypeptide (PACAP in the retina

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Tomoya eNakamachi

2012-11-01

Full Text Available Pituitary adenylate cyclase-activating polypeptide (PACAP, which is found in 27- or 38-amino acid forms, belongs to the VIP/glucagon/secretin family. PACAP and its three receptor subtypes are expressed in neural tissues, with PACAP known to exert a protective effect against several types of neural damage. The retina is considered to be part of the central nervous system, and retinopathy is a common cause of profound and intractable loss of vision. This review will examine the expression and morphological distribution of PACAP and its receptors in the retina, and will summarize the current state of knowledge regarding the protective effect of PACAP against different kinds of retinal damage, such as that identified in association with diabetes, ultraviolet light, hypoxia, optic nerve transection, and toxins. This article will also address PACAP-mediated protective pathways involving retinal glial cells.

Small molecule antagonists of integrin receptors.

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Perdih, A; Dolenc, M Sollner

2010-01-01

The complex and widespread family of integrin receptors is involved in numerous physiological processes, such as tissue remodeling, angiogenesis, development of the immune response and homeostasis. In addition, their key role has been elucidated in important pathological disorders such as cancer, cardiovascular diseases, osteoporosis, autoimmune and inflammatory diseases and in the pathogenesis of infectious diseases, making them highly important targets for modern drug design campaigns. In this review we seek to present a concise overview of the small molecule antagonists of this diverse and highly complex receptor family. Integrin antagonists are classified according to the targeted integrin receptor and are discussed in four sections. First we present the fibrinogen alpha(IIb)beta3 and the vitronectin alpha (V)beta(3) receptor antagonists. The remaining selective integrin antagonists are examined in the third section. The final section is dedicated to molecules with dual or multiple integrin activity. In addition, the use of antibodies and peptidomimetic approaches to modulate the integrin receptors are discussed, as well providing the reader with an overall appreciation of the field.

Adenylate Cyclase Toxin promotes bacterial internalisation into non phagocytic cells.

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Martín, César; Etxaniz, Asier; Uribe, Kepa B; Etxebarria, Aitor; González-Bullón, David; Arlucea, Jon; Goñi, Félix M; Aréchaga, Juan; Ostolaza, Helena

2015-09-08

Bordetella pertussis causes whooping cough, a respiratory infectious disease that is the fifth largest cause of vaccine-preventable death in infants. Though historically considered an extracellular pathogen, this bacterium has been detected both in vitro and in vivo inside phagocytic and non-phagocytic cells. However the precise mechanism used by B. pertussis for cell entry, or the putative bacterial factors involved, are not fully elucidated. Here we find that adenylate cyclase toxin (ACT), one of the important toxins of B. pertussis, is sufficient to promote bacterial internalisation into non-phagocytic cells. After characterization of the entry route we show that uptake of "toxin-coated bacteria" proceeds via a clathrin-independent, caveolae-dependent entry pathway, allowing the internalised bacteria to survive within the cells. Intracellular bacteria were found inside non-acidic endosomes with high sphingomyelin and cholesterol content, or "free" in the cytosol of the invaded cells, suggesting that the ACT-induced bacterial uptake may not proceed through formation of late endolysosomes. Activation of Tyr kinases and toxin-induced Ca(2+)-influx are essential for the entry process. We hypothesize that B. pertussis might use ACT to activate the endocytic machinery of non-phagocytic cells and gain entry into these cells, in this way evading the host immune system.

Pituitary adenylate cyclase activating polypeptide (PACAP) and its receptors are present and biochemically active in the central nervous system of the pond snail Lymnaea stagnalis.

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Pirger, Zsolt; Laszlo, Zita; Hiripi, Laszlo; Hernadi, Laszlo; Toth, Gabor; Lubics, Andrea; Reglodi, Dora; Kemenes, Gyorgy; Mark, Laszlo

2010-11-01

PACAP is a highly conserved adenylate cyclase (AC) activating polypeptide, which, along with its receptors (PAC1-R, VPAC1, and VPAC2), is expressed in both vertebrate and invertebrate nervous systems. In vertebrates, PACAP has been shown to be involved in associative learning, but it is not known if it plays a similar role in invertebrates. To prepare the way for a detailed investigation into the possible role of PACAP and its receptors in a suitable invertebrate model of learning and memory, here, we undertook a study of their expression and biochemical role in the central nervous system of the pond snail Lymnaea stagnalis. Lymnaea is one of the best established invertebrate model systems to study the molecular mechanisms of learning and memory, including the role of cyclic AMP-activated signaling mechanisms, which crucially depend on the learning-induced activation of AC. However, there was no information available on the expression of PACAP and its receptors in sensory structures and central ganglia of the Lymnaea nervous system known to be involved in associative learning or whether or not PACAP can actually activate AC in these ganglia. Here, using matrix-assisted laser desorption ionization time of flight (MALDI-TOF) and immunohistochemistry, we established the presence of PACAP-like peptides in the cerebral ganglia and the lip region of Lymnaea. The MALDI-TOF data indicated an identity with mammalian PACAP-27 and the presence of a squid-like PACAP-38 highly homologous to vertebrate PACAP-38. We also showed that PACAP, VIP, and maxadilan stimulated the synthesis of cAMP in Lymnaea cerebral ganglion homogenates and that this effect was blocked by the appropriate general and selective PACAP receptor antagonists.

Gonadotrophin releasing hormone antagonist in IVF/ICSI

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M S Kamath

2008-01-01

Full Text Available Objective : To study the efficacy of gonadotrophin releasing hormone (GnRH antagonist in In-vitro-fertilization/Intracytoplasmic sperm injection (IVF/ICSI cycles. Type of Study : Observational study. Setting: Reproductive Medicine Unit, Christian Medical College Hospital, Vellore, Tamil Nadu. Materials and Methods: GnRH antagonists were introduced into our practice in November 2005. Fifty-two women undergoing the antagonist protocol were studied and information gathered regarding patient profile, treatment parameters (total gonadotrophin dosage, duration of treatment, and oocyte yield, and outcomes in terms of embryological parameters (cleavage rates, implantation rates and clinical pregnancy. These parameters were compared with 121 women undergoing the standard long protocol. The costs between the two groups were also compared. Main Outcome : Clinical pregnancy rate. Results : The clinical pregnancy rate per embryo transfer in the antagonist group was 31.7% which was comparable to the clinical pregnancy rate in women undergoing the standard long protocol (30.63%. The costs between the two groups were comparable. Conclusions : GnRH antagonist protocol was found to be effective and comparable to the standard long protocol regimen. In addition it was simple, convenient, and patient friendly.

Molecular mechanism of 9-cis-retinoic acid inhibition of adipogenesis in 3T3-L1 cells

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Sagara, Chiaki; Takahashi, Katsuhiko; Kagechika, Hiroyuki; Takahashi, Noriko

2013-01-01

Highlights: ► We examined the effects of 9-cis-RA on adipogenesis in mouse preadipocyte 3T3-L1. ► 9-cis-RA inhibited lipid accumulation in adipogenetically-induced 3T3-L1 cells. ► A RXR pan-antagonist suppressed the inhibitory effects of 9-cis-RA on adipogenesis. ► This antagonist had no effects on RXRα and PPARγ levels in 9-cis-RA-treated cells. ► 9-cis-RA-induced decrease in both RXRα and PPARγ was independent of RXR activation. -- Abstract: Retinoic acid (RA) signaling is mediated by specific nuclear hormone receptors. Here we examined the effects of 9-cis-RA on adipogenesis in mouse preadipocyte 3T3-L1 cells. 9-cis-RA inhibits the lipid accumulation of adipogenetically induced 3T3-L1 cells. The complex of retinoid X receptor α (RXRα) with peroxisome proliferator-activated receptor γ (PPARγ) is a major transcription factor in the process of adipogenesis, and the levels of these molecules were decreased by 9-cis-RA treatment. A RXR pan-antagonist suppressed 9-cis-RA’s inhibitory effects on adipogenesis, but not on the intracellular levels of both RXRα and PPARγ. These results suggest that 9-cis-RA could inhibit adipogenesis by activating RXR, and decrease both RXR and PPARγs levels in a RXR activation-independent manner

Antagonistic activity of isolated lactic acid bacteria from Pliek U against gram-negative bacteria Escherichia coli ATCC 25922

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Kiti, A. A.; Jamilah, I.; Rusmarilin, H.

2017-09-01

Lactic acid bacteria (LAB) is one group of microbes that has many benefits, notably in food and health industries sector. LAB plays an important role in food fermentation and it has bacteriostatic effect against the growth of pathogenic microorganisms. The research related LAB continued to be done to increase the diversity of potential isolates derived from nature which is indigenous bacteria for biotechnological purposes. This study was aimed to isolate and characterize LAB derived from pliek u sample and to examine the potency to inhibits Escherichia coli ATCC 25922 bacteria growth. A total of 5 isolates were isolated and based on morphological and physiological characteristics of the fifth bacteria, they are allegedly belonging to the genus Bacillus. Result of antagonistic test showed that the five isolates could inhibits the growth of E. coli ATCC 25922. The highest inhibition zone is 8.5 mm was shown by isolates NQ2, while the lowest inhibition is 1.5 mm was shown by isolates NQ3.

Characterization of D1 dopamine receptors in the central nervous system

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Hess, E.J.

1987-01-01

Several lines of evidence suggest an association of central nervous system dopaminergic systems in the etiology of the schizophrenia. Interest in the role of D 1 dopamine receptors has revived with the advent of selective drugs for this dopamine receptor, particularly the D 1 dopamine receptor antagonists, SCH23390. [ 3 H]SCH23390 represents a superior radioligand for labeling the two-state striatal D 1 dopamine receptor in that its high percent specific binding makes it especially suitable for detailed mechanistic studies of this receptor. Striatal D 1 dopamine receptors have been shown to mediate the stimulation of adenylate cyclase activity via a guanine nucleotide regulatory subunit. Forskolin acts in a synergistic manner with dopamine agonists, guanine nucleotides or sodium fluoride to potentiate the stimulation of rat striatal adenylate cyclase activity mediated by these reagents. By using the aforementioned reagents and the irreversible receptor modifying reagent N-ethoxycarbonyl-2-ethoxy-1,2,-dihydroquinoline, we demonstrated that the D 1 dopamine receptor population in rat striatum is not a stoichiometrically-limiting factor in agonist stimulation of adenylate cyclase activity

Aryl Hydrocarbon Receptor Antagonists Mitigate the Effects of Dioxin on Critical Cellular Functions in Differentiating Human Osteoblast-Like Cells

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Chawon Yun

2018-01-01

Full Text Available The inhibition of bone healing in humans is a well-established effect associated with cigarette smoking, but the underlying mechanisms are still unclear. Recent work using animal cell lines have implicated the aryl hydrocarbon receptor (AhR as a mediator of the anti-osteogenic effects of cigarette smoke, but the complexity of cigarette smoke mixtures makes understanding the mechanisms of action a major challenge. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD, dioxin is a high-affinity AhR ligand that is frequently used to investigate biological processes impacted by AhR activation. Since there are dozens of AhR ligands present in cigarette smoke, we utilized dioxin as a prototype ligand to activate the receptor and explore its effects on pro-osteogenic biomarkers and other factors critical to osteogenesis using a human osteoblast-like cell line. We also explored the capacity for AhR antagonists to protect against dioxin action in this context. We found dioxin to inhibit osteogenic differentiation, whereas co-treatment with various AhR antagonists protected against dioxin action. Dioxin also negatively impacted cell adhesion with a corresponding reduction in the expression of integrin and cadherin proteins, which are known to be involved in this process. Similarly, the dioxin-mediated inhibition of cell migration correlated with reduced expression of the chemokine receptor CXCR4 and its ligand, CXCL12, and co-treatment with antagonists restored migratory capacity. Our results suggest that AhR activation may play a role in the bone regenerative response in humans exposed to AhR activators, such as those present in cigarette smoke. Given the similarity of our results using a human cell line to previous work done in murine cells, animal models may yield data relevant to the human setting. In addition, the AhR may represent a potential therapeutic target for orthopedic patients who smoke cigarettes, or those who are exposed to secondhand smoke or other

History of the 'geste antagoniste' sign in cervical dystonia.

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Poisson, A; Krack, P; Thobois, S; Loiraud, C; Serra, G; Vial, C; Broussolle, E

2012-08-01

The geste antagoniste is a voluntary maneuver that temporarily reduces the severity of dystonic posture or movements. It is a classical feature of focal and particularly cervical dystonia. However, the precise historical aspects of geste antagoniste still remain obscure. The goals of this review were (1) to clarify the origin of the geste antagoniste sign; (2) to identify the factors that led to its diffusion in the international literature; (3) to follow the evolution of that term across the twentieth century. We used medical and neurological French, German and English literature of the late nineteenth and early twentieth centuries, and the PubMed database by entering the terms geste antagoniste, antagonistic gesture and sensory trick. The geste antagoniste sign is a legacy of the Paris Neurological School of the end of the nineteenth century. The term was introduced by Meige and Feindel in their 1902 book on tics, written in the vein of their master, Brissaud, who first described this sign in 1893. The almost immediate translations of this book by Giese into German and Kinnier Wilson into English contributed to the rapid spreading of the term geste antagoniste, which is still in use worldwide today. The term antagonistic gesture is the translation proposed by Kinnier Wilson, which also led to the use of the term geste antagonistique. The geste antagoniste sign has long been considered a solid argument for the psychogenic origins of dystonia until the 1980s when Marsden made strong arguments for its organic nature.

Energetics and Structural Characterization of the large-scale Functional Motion of Adenylate Kinase

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Formoso, Elena; Limongelli, Vittorio; Parrinello, Michele

2015-02-01

Adenylate Kinase (AK) is a signal transducing protein that regulates cellular energy homeostasis balancing between different conformations. An alteration of its activity can lead to severe pathologies such as heart failure, cancer and neurodegenerative diseases. A comprehensive elucidation of the large-scale conformational motions that rule the functional mechanism of this enzyme is of great value to guide rationally the development of new medications. Here using a metadynamics-based computational protocol we elucidate the thermodynamics and structural properties underlying the AK functional transitions. The free energy estimation of the conformational motions of the enzyme allows characterizing the sequence of events that regulate its action. We reveal the atomistic details of the most relevant enzyme states, identifying residues such as Arg119 and Lys13, which play a key role during the conformational transitions and represent druggable spots to design enzyme inhibitors. Our study offers tools that open new areas of investigation on large-scale motion in proteins.

Characteristics of the binding of (/sup 3/H)nitrendipine to rabbit ventricular membranes: modification by other Ca++ channel antagonists and by the Ca++ channel agonist Bay K 8644

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Janis, R.A.; Sarmiento, J.G.; Maurer, S.C.; Bolger, G.T.; Triggle, D.J.

1984-10-01

This study was carried out to characterize (/sup 3/H)nitrendipine binding to cardiac membranes and to test the hypothesis that high affinity binding of Ca++ channel antagonists and agonists is to Ca++ channels. Binding was specific, rapid, reversible and stereoselective. The relative order of potency of nifedipine analogs for inhibition of binding was the same as that for inhibition of smooth and cardiac muscle contraction. Results with diltiazem, verapamil and lidoflazine were consistent with the hypothesis that nondihydropyridine Ca++ channel antagonists act at one or more sites allosterically linked to the 1,4-dihydropyridine site in cardiac cells. The Ca++ channel agonist Bay K 8644 (methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine- 5-carboxylate) displaced specifically bound (/sup 3/H)nitrendipine in an apparently competitive manner with an IC50 value of 5 nM. The results suggest that organic antagonists do not act by physically blocking the Ca++ channel. The data also support the hypothesis that the high affinity binding sites for (/sup 3/H)nitrendipine in isolated cardiac membranes are associated with Ca++ channels that are inactivated or are otherwise unavailable for opening.

Pregnancy outcome of “delayed start” GnRH antagonist protocol versus GnRH antagonist protocol in poor responders: A clinical trial study

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Abbas Aflatoonian

2017-08-01

Full Text Available Background: Management of poor-responding patients is still major challenge in assisted reproductive techniques (ART. Delayed-start GnRH antagonist protocol is recommended to these patients, but little is known in this regards. Objective: The goal of this study was assessment of delayed-start GnRH antagonist protocol in poor responders, and in vitro fertilization (IVF outcomes. Materials and Methods: This randomized clinical trial included sixty infertile women with Bologna criteria for ovarian poor responders who were candidate for IVF. In case group (n=30, delayed-start GnRH antagonist protocol administered estrogen priming followed by early follicular-phase GnRH antagonist treatment for 7 days before ovarian stimulation with gonadotropin. Control group (n=30 treated with estrogen priming antagonist protocol. Finally, endometrial thickness, the rates of oocytes maturation, , embryo formation, and pregnancy were compared between two groups. Results: Rates of implantation, chemical, clinical, and ongoing pregnancy in delayed-start cycles were higher although was not statistically significant. Endometrial thickness was significantly higher in case group. There were no statistically significant differences in the rates of oocyte maturation, embryo formation, and IVF outcomes between two groups. Conclusion: There is no significant difference between delayed-start GnRH antagonist protocol versus GnRH antagonist protocol.

Isolation and Characterization of Actinomycete Antagonists of a Fungal Root Pathogen †

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Crawford, Don L.; Lynch, James M.; Whipps, John M.; Ousley, Margaret A.

1993-01-01

By use of selective media, 267 actinomycete strains were isolated from four rhizosphere-associated and four non-rhizosphere-associated British soils. Organic media with low nutrient concentrations were found to be best for isolating diverse actinomycetes while avoiding contamination and overgrowth of isolation media by eubacteria and fungi. While all isolates grew well at pHs 6.5 to 8.0, a few were unable to grow at pH 6.0 and a significant number failed to grow at pH 5.5. Eighty-two selected isolates were screened for in vitro antagonism towards Pythium ultimum by use of a Difco cornmeal agar assay procedure. Five isolates were very strong antagonists of the fungus, four were strong antagonists, and ten others were weakly antagonistic. The remaining isolates showed no antagonism by this assay. Additional studies showed that several of the P. ultimum antagonists also strongly inhibited growth of other root-pathogenic fungi. Twelve isolates showing antifungal activity in the in vitro assay were also tested for their effects on the germination and short-term growth of lettuce plants in glasshouse pot studies in the absence of pathogens. None of the actinomycetes prevented seed germination, although half of the isolates retarded seed germination and outgrowth of the plants by 1 to 3 days. During 18-day growth experiments, biomass yields of some actinomycete-inoculated plants were reduced in comparison with untreated control plants, although all plants appeared healthy and well rooted. None of the actinomycetes significantly enhanced plant growth over these short-term experiments. For some, but not all, actinomycetes, some correlations between delayed seed germination and reduced 18-day plant biomass yields were seen. For others, plant biomass yields were not reduced despite an actinomycete-associated delay in seed germination and plant outgrowth. Preliminary glasshouse experiments indicated that some of the actinomycetes protect germinating lettuce seeds against

The combination of glutamate receptor antagonist MK-801 with tamoxifen and its active metabolites potentiates their antiproliferative activity in mouse melanoma K1735-M2 cells

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Ribeiro, Mariana P.C.; Nunes-Correia, Isabel; Santos, Armanda E.; Custódio, José B.A.

2014-01-01

Recent reports suggest that N-methyl-D-aspartate receptor (NMDAR) blockade by MK-801 decreases tumor growth. Thus, we investigated whether other ionotropic glutamate receptor (iGluR) antagonists were also able to modulate the proliferation of melanoma cells. On the other hand, the antiestrogen tamoxifen (TAM) decreases the proliferation of melanoma cells, and is included in combined therapies for melanoma. As the efficacy of TAM is limited by its metabolism, we investigated the effects of the NMDAR antagonist MK-801 in combination with TAM and its active metabolites, 4-hydroxytamoxifen (OHTAM) and endoxifen (EDX). The NMDAR blockers MK-801 and memantine decreased mouse melanoma K1735-M2 cell proliferation. In contrast, the NMDAR competitive antagonist APV and the AMPA and kainate receptor antagonist NBQX did not affect cell proliferation, suggesting that among the iGluR antagonists only the NMDAR channel blockers inhibit melanoma cell proliferation. The combination of antiestrogens with MK-801 potentiated their individual effects on cell biomass due to diminished cell proliferation, since it decreased the cell number and DNA synthesis without increasing cell death. Importantly, TAM metabolites combined with MK-801 promoted cell cycle arrest in G1. Therefore, the data obtained suggest that the activity of MK-801 and antiestrogens in K1735-M2 cells is greatly enhanced when used in combination. - Highlights: • MK-801 and memantine decrease melanoma cell proliferation. • The combination of MK-801 with antiestrogens inhibits melanoma cell proliferation. • These combinations greatly enhance the effects of the compounds individually. • MK-801 combined with tamoxifen active metabolites induces cell cycle arrest in G1. • The combination of MK-801 and antiestrogens is an innovative strategy for melanoma

In vitro study of alpha 2-adrenoceptor turnover and metabolism using the adenocarcinoma cell line HT29

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Paris, H.; Taouis, M.; Galitzky, J.

1987-01-01

The biosynthesis rate of the receptor was studied in postconfluent HT29 cells, when its density expressed as fmol/mg of cell membrane protein is constant, by following the recovery of the receptor binding capacity after blockade with the non-reversible alpha-adrenergic antagonist benextramine. Study of the inhibition of [ 3 H]yohimbine and [ 3 H]UK-14,304 binding showed that benextramine was a more potent antagonist at alpha 2-adrenoceptor than phenoxybenzamine. The incubation of intact HT29 cells for 30 min in the presence of 10(-5) M benextramine irreversibly blocked more than 95% of the alpha 2-adrenoceptors and totally suppressed the inhibitory effect of UK-14,304 on cyclic AMP production. The blockade appeared specific, since benextramine effects were prevented by alpha 2-adrenergic agents. Moreover, neither vasoactive intestinal polypeptide responsiveness nor other tested aspects of the regulation of the adenylate cyclase was altered by the treatment. Study of the time course of receptor recovery after irreversible blockade indicated that alpha 2-adrenoceptors reappeared in the cells with a monoexponential kinetic. The linearization of the repopulation curve obtained with the labeled antagonist [ 3 H]yohimbine allowed the determination of the rate constant for receptor degradation (k = 0.0268 +/- 0.0025 hr-1) and the rate of receptor synthesis (6.91 +/- 0.64 fmol/mg of cell membrane protein/hr) corresponding to the synthesis of about 500 receptors/cell/hr. The alpha 2-adrenoceptor half-life was 26 +/- 3 hr. Measurement of the biological effects associated to the alpha-adrenoceptor stimulation during the course of receptor recovery indicated a relationship between the number of cell receptors and the percentage of inhibition of the cyclic AMP accumulation induced by forskolin

Group I mGluR antagonist rescues the deficit of D1-induced LTP in a mouse model of fragile X syndrome

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Xu Zhao-Hui

2012-05-01

Full Text Available Abstract Background Fragile X syndrome (FXS is caused by the absence of the mRNA-binding protein Fragile X mental retardation protein (FMRP, encoded by the Fmr1 gene. Overactive signaling by group 1 metabotropic glutamate receptor (Grp1 mGluR could contribute to slowed synaptic development and other symptoms of FXS. Our previous study has identified that facilitation of synaptic long-term potentiation (LTP by D1 receptor is impaired in Fmr1 knockout (KO mice. However, the contribution of Grp1 mGluR to the facilitation of synaptic plasticity by D1 receptor stimulation in the prefrontal cortex has been less extensively studied. Results Here we demonstrated that DL-AP3, a Grp1 mGluR antagonist, rescued LTP facilitation by D1 receptor agonist SKF81297 in Fmr1KO mice. Grp1 mGluR inhibition restored the GluR1-subtype AMPA receptors surface insertion by D1 activation in the cultured Fmr1KO neurons. Simultaneous treatment of Grp1 mGluR antagonist with D1 agonist recovered the D1 receptor signaling by reversing the subcellular redistribution of G protein-coupled receptor kinase 2 (GRK2 in the Fmr1KO neurons. Treatment of SKF81297 alone failed to increase the phosphorylation of NR2B-containing N-methyl D-aspartate receptors (NMDARs at Tyr-1472 (p-NR2B-Tyr1472 in the cultures from KO mice. However, simultaneous treatment of DL-AP3 could rescue the level of p-NR2B-Tyr1472 by SKF81297 in the cultures from KO mice. Furthermore, behavioral tests indicated that simultaneous treatment of Grp1 mGluR antagonist with D1 agonist inhibited hyperactivity and improved the learning ability in the Fmr1KO mice. Conclusion The findings demonstrate that mGluR1 inhibition is a useful strategy to recover D1 receptor signaling in the Fmr1KO mice, and combination of Grp1 mGluR antagonist and D1 agonist is a potential drug therapy for the FXS.

Identification of an endogenous alpha-adrenergic receptor antagonist: studies on its possible role in endocrine and cardiovascular function

International Nuclear Information System (INIS)

Dunbar, J.C.; Wider, M.; House, F.; Campbell, R.

1986-01-01

The concept of α and β adrenergic receptors that are regulated by epinephrine or norepinephrine (NE) is well established. The reported receptor antagonists have been synthetic. A peptide extracted from the duodenal mucosa with α-2 antagonist properties has been identified. It specifically inhibits 3 H-yohimbine binding (α-2) but not 3 H dihydroalprenolol (β) binding in whole brain membranes. Partially purified preparations of the alpha receptor binding inhibitor (ABI) were tested for endocrine pancreatic and cardiovascular effects. When isolated islets were incubated in the presence of ABI with and without NE, ABI along did not alter insulin secretion but completely reversed the NE suppression of glucose stimulated insulin release. Glucagon secretion by these same islets was enhanced by ABI and augmented the stimulatory effect of NE. Intravenous (I.V.) infusion of ABI increased serum insulin in the presence of NE and decreased the serum glucose response to a glucose load. Infusion of ABI into the 4th ventricle, or I.V. resulted in a decrease (50-60%) in systolic and diastolic blood pressure as well as a decrease (10-20%) in heart rate. From these studies the authors conclude that a duodenal peptide with the capacity to inhibit α-2 agonist binding may play a role in endocrine and cardiovascular functions

The effects of corticotrophin-releasing factor and two antagonists on breathing movements in fetal sheep.

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Bennet, L; Johnston, B M; Vale, W W; Gluckman, P D

1990-01-01

1. The respiratory effects of corticotrophin-releasing factor (CRF) and the CRF antagonists alpha-helical CRF 9-41 (alpha hCRF) and [DPhe 12, Nle 21-38] rCRF (12-41) (DPhe CRF) have been studied in unanaesthetized fetal lambs of 125-140 days gestation. 2. CRF when given as a 10 micrograms bolus followed by a 5 micrograms h-1 infusion into a lateral cerebral ventricle caused prolonged continuous fetal breathing movements which were stimulated in both amplitude and frequency but which did not persist during hypoxia. 3. Lower doses of CRF (20 ng bolus followed by 10 ng h-1) increased the amplitude but not the frequency of fetal breathing movements which did not become continuous. 4. At higher doses (20 micrograms bolus followed by 10-15 micrograms h-1) CRF induced cerebral convulsions which were also associated with fetal breathing movements of increased amplitude and frequency. 5. The CRF antagonists alpha hCRF and DPhe CRF both inhibited fetal breathing movements and induced a prolonged apnoea which was resistant to the stimulatory effects of 5-6% hypercapnia. 6. We conclude that CRF stimulates breathing movements in the fetal lamb. The finding that administration of the CRF antagonists alone cause apnoea suggests that CRF may have a tonic role in the regulation of fetal breathing movements. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:2348387

Preliminary Structure-Activity Relationship on Theonellasterol, a New Chemotype of FXR Antagonist, from the Marine Sponge Theonella swinhoei

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Stefano Fiorucci

2012-11-01

Full Text Available Using theonellasterol as a novel FXR antagonist hit, we prepared a series of semi-synthetic derivatives in order to gain insight into the structural requirements for exhibiting antagonistic activity. These derivatives are characterized by modification at the exocyclic carbon-carbon double bond at C-4 and at the hydroxyl group at C-3 and were prepared from theonellasterol using simple reactions. Pharmacological investigation showed that the introduction of a hydroxyl group at C-4 as well as the oxidation at C-3 with or without concomitant modification at the exomethylene functionality preserve the ability of theonellasterol to inhibit FXR transactivation caused by CDCA. Docking analysis showed that the placement of these molecules in the FXR-LBD is well stabilized when on ring A functional groups, able to form hydrogen bonds and π interactions, are present.

Transcriptional and Antagonistic Responses of Biocontrol Strain Lysobacter enzymogenes OH11 to the Plant Pathogenic Oomycete Pythium aphanidermatum

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Yangyang Zhao

2017-06-01

Full Text Available Lysobacter enzymogenes is a ubiquitous, beneficial, plant-associated bacterium emerging as a novel biological control agent. It has the potential to become a new source of antimicrobial secondary metabolites such as the Heat-Stable Antifungal Factor (HSAF, which is a broad-spectrum antimycotic with a novel mode of action. However, very little information about how L. enzymogenes detects and responds to fungi or oomycetes has been reported. An in vitro confrontation bioassay between the pathogenic oomycete Pythium aphanidermatum and the biocontrol bacterial strain L. enzymogenes OH11 was used to analyze the transcriptional changes in the bacteria that were induced by the oomycetes. Analysis was performed at three time points of the interaction, starting before inhibition zone formation until inhibition zone formation. A L. enzymogenes OH11 DNA microarray was constructed for the analysis. Microarray analysis indicated that a wide range of genes belonging to 14 diverse functions in L. enzymogenes were affected by P. aphanidermatum as critical antagonistic effects occurred. L. enzymogenes detected and responded to the presence of P. aphanidermatum early, but alteration of gene expression typically occurred after inhibition zone formation. The presence of P. aphanidermatum increased the twitching motility and HSAF production in L. enzymogenes. We also performed a contact interaction between L. enzymogenes and P. aphanidermatum, and found that HSAF played a critical role in the interaction. Our experiments demonstrated that L. enzymogenes displayed transcriptional and antagonistic responses to P. aphanidermatum in order to gain advantages in the competition with this oomycete. This study revealed new insights into the interactions between bacteria and oomycete.

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

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Varghese Rlnoy

2014-05-01

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.

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

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Lixin Wang

2011-02-01

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.

Systemic EP4 Inhibition Increases Adhesion Formation in a Murine Model of Flexor Tendon Repair.

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Michael B Geary

Full Text Available Flexor tendon injuries are a common clinical problem, and repairs are frequently complicated by post-operative adhesions forming between the tendon and surrounding soft tissue. Prostaglandin E2 and the EP4 receptor have been implicated in this process following tendon injury; thus, we hypothesized that inhibiting EP4 after tendon injury would attenuate adhesion formation. A model of flexor tendon laceration and repair was utilized in C57BL/6J female mice to evaluate the effects of EP4 inhibition on adhesion formation and matrix deposition during flexor tendon repair. Systemic EP4 antagonist or vehicle control was given by intraperitoneal injection during the late proliferative phase of healing, and outcomes were analyzed for range of motion, biomechanics, histology, and genetic changes. Repairs treated with an EP4 antagonist demonstrated significant decreases in range of motion with increased resistance to gliding within the first three weeks after injury, suggesting greater adhesion formation. Histologic analysis of the repair site revealed a more robust granulation zone in the EP4 antagonist treated repairs, with early polarization for type III collagen by picrosirius red staining, findings consistent with functional outcomes. RT-PCR analysis demonstrated accelerated peaks in F4/80 and type III collagen (Col3a1 expression in the antagonist group, along with decreases in type I collagen (Col1a1. Mmp9 expression was significantly increased after discontinuing the antagonist, consistent with its role in mediating adhesion formation. Mmp2, which contributes to repair site remodeling, increases steadily between 10 and 28 days post-repair in the EP4 antagonist group, consistent with the increased matrix and granulation zones requiring remodeling in these repairs. These findings suggest that systemic EP4 antagonism leads to increased adhesion formation and matrix deposition during flexor tendon healing. Counter to our hypothesis that EP4 antagonism

Antagonistic parent-offspring co-adaptation.

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Mathias Kölliker

2010-01-01

Full Text Available 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.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.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.

Translational overview of cytokine inhibition in acute myocardial infarction and chronic heart failure.

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Hartman, Minke H T; Groot, Hilde E; Leach, Irene Mateo; Karper, Jacco C; van der Harst, Pim

2018-02-15

Many cytokines are currently under investigation as potential target to improve cardiac function and outcome in the setting of acute myocardial infarction (MI) or chronic heart failure (HF). Here we aim to provide a translational overview of cytokine inhibiting therapies tested in experimental models and clinical studies. In various experimental studies, inhibition of interleukin-1 (IL-1), -6 (IL-6), -8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), CC- and CXC chemokines, and tumor necrosis factor-α (TNF-α) had beneficial effects on cardiac function and outcome. On the other hand, neutral or even detrimental results have been reported for some (IL-1, IL-6, IL-8, and MCP-1). Ambivalence of cytokine function, differences in study designs, treatment regimens and chosen endpoints hamper the translation of experimental research into clinical practice. Human studies are currently limited to IL-1β inhibition, IL-1 receptor antagonists (IL-1RA), IL-6 receptor antagonists (IL-6RA) or TNF inhibition. Despite favorable effects on cardiovascular events observed in retrospective cohort studies of rheumatoid arthritis patients treated with TNF inhibition or IL-1RA, most prospective studies reported disappointing and inconsistent results. Smaller studies (n 100) evaluating IL-1β inhibition presented positive results on outcome. In conclusion, of the 10 anticytokine therapies tested in animals models beneficial effects have been reported in at least one setting. In larger clinical studies, findings were unsatisfactory in all but one. Many anticytokine therapies with promising animal experimental data continue to require further evaluation in humans. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Inhibition of tumor cell growth by Sigma1 ligand mediated translational repression

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Kim, Felix J.; Schrock, Joel M.; Spino, Christina M.; Marino, Jacqueline C.; Pasternak, Gavril W.

2012-01-01

Highlights: ► Sigma1 ligand treatment mediates decrease in tumor cell mass. ► Identification of a Sigma1 ligand with reversible translational repressor actions. ► Demonstration of a role for Sigma1 in cellular protein synthesis. -- Abstract: Treatment with sigma1 receptor (Sigma1) ligands can inhibit cell proliferation in vitro and tumor growth in vivo. However, the cellular pathways engaged in response to Sigma1 ligand treatment that contribute to these outcomes remain largely undefined. Here, we show that treatment with putative antagonists of Sigma1 decreases cell mass. This effect corresponds with repressed cap-dependent translation initiation in multiple breast and prostate cancer cell lines. Sigma1 antagonist treatment suppresses phosphorylation of translational regulator proteins p70S6K, S6, and 4E-BP1. RNAi-mediated knockdown of Sigma1 also results in translational repression, consistent with the effects of antagonist treatment. Sigma1 antagonist mediated translational repression and decreased cell size are both reversible. Together, these data reveal a role for Sigma1 in tumor cell protein synthesis, and demonstrate that small molecule Sigma1 ligands can be used as modulators of protein translation.

Antagonistic activity of marine sponges associated Actinobacteria

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Selvakumar Dharmaraj

2016-06-01

Full Text Available 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

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

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Andrew John Dudley Nelson

2013-05-01

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.

Does protein binding modulate the effect of angiotensin II receptor antagonists?

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Marc P Maillard

2001-03-01

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.

Transmembrane segments of complement receptor 3 do not participate in cytotoxic activities but determine receptor structure required for action of Bordetella adenylate cyclase toxin

Czech Academy of Sciences Publication Activity Database

Wald, Tomáš; Osičková, Adriana; Mašín, Jiří; Matyska Lišková, Petra; Petry-Podgorska, Inga; Matoušek, Tomáš; Šebo, Peter; Osička, Radim

2016-01-01

Roč. 74, č. 3 (2016), flw008 ISSN 2049-632X R&D Projects: GA ČR(CZ) GAP302/11/0580; GA ČR GAP302/12/0460; GA ČR GA13-14547S Institutional support: RVO:61388971 ; RVO:68081715 Keywords : adenylate cyclase toxin * ICP-MS * CD11b/CD18 Subject RIV: EE - Microbiology, Virology; CB - Analytical Chemistry, Separation (UIACH-O) Impact factor: 2.335, year: 2016

Pharmacological characterization of LY233053: A structurally novel tetrazole-substituted competitive N-methyl-D-aspartic acid antagonist with a short duration of action

International Nuclear Information System (INIS)

Schoepp, D.D.; Ornstein, P.L.; Leander, J.D.; Lodge, D.; Salhoff, C.R.; Zeman, S.; Zimmerman, D.M.

1990-01-01

This study reports the activity of a structurally novel excitatory amino acid receptor antagonist, LY233053 [cis-(+-)-4-[(2H-tetrazol-5-yl)methyl]piperidine-2-carboxylic acid], the first tetrazole-containing competitive N-methyl-D-aspartic acid (NMDA) antagonist. LY233053 potently inhibited NMDA receptor binding to rat brain membranes as shown by the in vitro displacement of [3H] CGS19755 (IC50 = 107 +/- 7 nM). No appreciable affinity in [3H]alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) or [3H]kainate binding assays was observed (IC50 values greater than 10,000 nM). In vitro NMDA receptor antagonist activity was further demonstrated by selective inhibition of NMDA-induced depolarization in cortical wedges (IC50 = 4.2 +/- 0.4 microM vs. 40 microM NMDA). LY233053 was effective after in vivo systemic administration in a number of animal models. In neonatal rats, LY233053 selectively blocked NMDA-induced convulsions (ED50 = 14.5 mg/kg i.p.) with a relatively short duration of action (2-4 hr). In pigeons, LY233053 potently antagonized (ED50 = 1.3 mg/kg i.m.) the behavioral suppressant effects of 10 mg/kg of NMDA. However, a dose of 160 mg/kg, i.m., was required to produce phencyclidine-like catalepsy in pigeons. In mice, LY233053 protected against maximal electroshock-induced seizures at lower doses (ED50 = 19.9 mg/kg i.p.) than those that impaired horizontal screen performance (ED50 = 40.9 mg/kg i.p.). Cholinergic and GABAergic neuronal degenerations after striatal infusion of NMDA were prevented by single or multiple i.p. doses of LY233053. In summary, the antagonist activity of LY233053 after systemic administration demonstrates potential therapeutic value in conditions of neuronal cell loss due to NMDA receptor excitotoxicity

MELATONIN-INDUCED SUPPRESSION OF PC12 CELL GROWTH IS MEDIATED BY ITS GI COUPLED TRANSMEMBRANE RECEPTORS. (R826248)

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The effects of pertussis toxin, an uncoupler of Gi protein from adenylate cyclase, and luzindole, a competitive inhibitor of melatonin receptor binding, were examined for their ability to inhibit melatonin-induced suppression of PC12 cell growth. Both agents inhibited the mela...

The analgesic agent tapentadol inhibits calcitonin gene-related peptide release from isolated rat brainstem via a serotonergic mechanism.

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Greco, Maria Cristina; Navarra, Pierluigi; Tringali, Giuseppe

2016-01-15

In this study we tested the hypothesis that tapentadol inhibits GGRP release from the rat brainstem through a mechanism mediated by the inhibition of NA reuptake; as a second alternative hypothesis, we investigated whether tapentadol inhibits GGRP release via the inhibition of 5-HT reuptake. Rat brainstems were explanted and incubated in short-term experiments. CGRP released in the incubation medium was taken as a marker of CGRP release from the central terminals of trigeminal neurons within the brainstem. CGRP levels were measured by radioimmunoassay under basal conditions or in the presence of tapentadol; NA, 5-HT, clonidine, yohimbine and ondansetron were used as pharmacological tools to investigate the action mechanism of tapentadol. The α2-antagonist yohimbine failed to counteract the effects of tapentadol. Moreover, neither NA nor the α2-agonist clonidine per se inhibited K(+)-stimulated CGRP release, thereby indicating that the effects of tapentadol are nor mediated through the block of NA reuptake. Further experiments showed that 5-HT and tramadol, which inhibits both NA and 5-HT reuptake, significantly reduced K(+)-stimulated CGRP release. Moreover, the 5-HT3 antagonist ondansetron was able to counteract the effects of tapentadol in this system. This study provided pharmacological evidence that tapentadol inhibits stimulated CGRP release from the rat brainstem in vitro through a mechanism involving an increase in 5-HT levels in the system and the subsequent activation of 5-HT3 receptors. Copyright © 2015 Elsevier Inc. All rights reserved.

Delivering the lateral inhibition punchline: it's all about the timing.

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Axelrod, Jeffrey D

2010-10-26

Experimental and theoretical biologists have long been fascinated with the emergence of self-organizing patterns in developing organisms, and much attention has focused on Notch-mediated lateral inhibition. Within sheets of cells that may adopt either of two possible cell fates, lateral inhibition establishes patterns through the activity of a negative intercellular feedback loop involving the receptor, Notch, and its ligands Delta or Serrate. Despite a long history of intensive study in Drosophila, where the mechanism was first described, as well as in other organisms, new work continues to yield important insights. Mathematical modeling, combined with biological analyses, has now shed light on two features of the process: how antagonistic and activating ligand-receptor interactions work together to accelerate inhibition and ensure fidelity, and how filopodial dynamics contribute to the observed pattern refinement and spacing.

Leptin reverses corticosterone-induced inhibition of neural stem cell proliferation through activating the NR2B subunits of NMDA receptors

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Shi, Wen-Zhu [Anesthesia and Operation Center, Hainan Branch of Chinese PLA General Hospital, Hainan 572013 (China); Anesthesia and Operation Center, Chinese PLA General Hospital, Beijing 100853 (China); Miao, Yu-Liang [Department of Anesthesiology, PLA No. 306 Hospital, Beijing 100101 (China); Guo, Wen-Zhi [Department of Anesthesiology, Beijing Military General Hospital of Chinese People’s Liberation Army, Beijing 100700 (China); Wu, Wei, E-mail: wwzwgk@163.com [Department of Head and Neck Surgery of Otolaryngology, PLA No. 306 Hospital, Beijing 100101 (China); Li, Bao-Wei [Department of Head and Neck Surgery of Otolaryngology, PLA No. 306 Hospital, Beijing 100101 (China); An, Li-Na [Department of Anesthesiology, Armed Police General Hospital, Beijing 100039 (China); Fang, Wei-Wu [Department of Anesthesiology, PLA No. 306 Hospital, Beijing 100101 (China); Mi, Wei-Dong, E-mail: elite2005gg@163.com [Anesthesia and Operation Center, Chinese PLA General Hospital, Beijing 100853 (China)

2014-04-25

Highlights: • Leptin promotes the proliferation of neural stem cells isolated from embryonic mouse hippocampus. • Leptin reverses corticosterone-induced inhibition of neural stem cell proliferation. • The effects of leptin are partially mediated by upregulating NR2B subunits. - Abstract: Corticosterone inhibits the proliferation of hippocampal neural stem cells (NSCs). The removal of corticosterone-induced inhibition of NSCs proliferation has been reported to contribute to neural regeneration. Leptin has been shown to regulate brain development, improve angiogenesis, and promote neural regeneration; however, its effects on corticosterone-induced inhibition of NSCs proliferation remain unclear. Here we reported that leptin significantly promoted the proliferation of hippocampal NSCs in a concentration-dependent pattern. Also, leptin efficiently reversed the inhibition of NSCs proliferation induced by corticosterone. Interestingly, pre-treatment with non-specific NMDA antagonist MK-801, specific NR2B antagonist Ro 25-6981, or small interfering RNA (siRNA) targeting NR2B, significantly blocked the effect of leptin on corticosterone-induced inhibition of NSCs proliferation. Furthermore, corticosterone significantly reduced the protein expression of NR2B, whereas pre-treatment with leptin greatly reversed the attenuation of NR2B expression caused by corticosterone in cultured hippocampal NSCs. Our findings demonstrate that leptin reverses the corticosterone-induced inhibition of NSCs proliferation. This process is, at least partially mediated by increased expression of NR2B subunits of NMDA receptors.

Palmitoylethanolamide Inhibits Glutamate Release in Rat Cerebrocortical Nerve Terminals

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Tzu-Yu Lin

2015-03-01

Full Text Available The effect of palmitoylethanolamide (PEA, an endogenous fatty acid amide displaying neuroprotective actions, on glutamate release from rat cerebrocortical nerve terminals (synaptosomes was investigated. PEA inhibited the Ca2+-dependent release of glutamate, which was triggered by exposing synaptosomes to the potassium channel blocker 4-aminopyridine. This release inhibition was concentration dependent, associated with a reduction in cytosolic Ca2+ concentration, and not due to a change in synaptosomal membrane potential. The glutamate release-inhibiting effect of PEA was prevented by the Cav2.1 (P/Q-type channel blocker ω-agatoxin IVA or the protein kinase A inhibitor H89, not affected by the intracellular Ca2+ release inhibitors dantrolene and CGP37157, and partially antagonized by the cannabinoid CB1 receptor antagonist AM281. Based on these results, we suggest that PEA exerts its presynaptic inhibition, likely through a reduction in the Ca2+ influx mediated by Cav2.1 (P/Q-type channels, thereby inhibiting the release of glutamate from rat cortical nerve terminals. This release inhibition might be linked to the activation of presynaptic cannabinoid CB1 receptors and the suppression of the protein kinase A pathway.

Inhibition of common cold-induced aggravation of childhood asthma by leukotriene receptor antagonists.

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Yoshihara, Shigemi; Fukuda, Hironobu; Abe, Toshio; Nishida, Mitsuhiro; Yamada, Yumi; Kanno, Noriko; Arisaka, Osamu

2012-09-01

Virus infection is an important risk factor for aggravation of childhood asthma. The objective of this study was to examine the effect of drugs on aggravation of asthma induced by a common cold. Asthma control was examined in a survey of 1,014 Japanese pediatric patients with bronchial asthma. The occurrence of common cold, asthma control, and drugs used for asthma control were investigated using a modified Childhood Asthma Control Test (C-ACT) for patients aged cold and aggravation of asthma were significantly higher in patients aged cold-induced aggravation was significantly less effective in patients aged cold, asthma control was significantly more effective for those treated with leukotriene receptor antagonists (LTRAs) compared to treatment without LTRAs. Asthma control did not differ between patients who did or did not take inhaled corticosteroids or long-acting β2 stimulants. These findings showed a high prevalence of common cold in younger patients with childhood asthma and indicated that common cold can induce aggravation of asthma. LTRAs are useful for long-term asthma control in very young patients who develop an asthma attack due to a common cold.

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

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Brudvik Kristoffer W

2011-12-01

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.

Contribution of adrenal hormones to nicotine-induced inhibition of synovial plasma extravasation in the rat.

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Miao, F J; Benowitz, N L; Heller, P H; Levine, J D

1997-01-01

1. In this study, we examined the mechanism(s) by which s.c. nicotine inhibits synovial plasma extravasation. We found that nicotine dose-dependently inhibited bradykinin (BK)- and platelet activating factor (PAF)-induced plasma extravasation. 2. The effect of nicotine on both BK- and PAF-induced plasma extravasation was attenuated by adrenal medullectomy. ICI-118,551 (a selective beta 2-adrenoceptor blocker) (30 micrograms ml-1, intra-articularly) significantly attenuated the inhibitory action of high-dose (1 mg kg-1) nicotine on BK-induced plasma extravasation without affecting the inhibition by low- (0.01 microgram kg-1) dose nicotine or that on PAF-induced plasma extravasation by nicotine at any dose. This suggested that beta 2-adrenoceptors mediate the inhibitory actions of high-dose, but not low-dose, nicotine. We also found that systemic naloxone (an opioid receptor antagonist) (two hourly injections of 1 mg kg-1, i.p.) attenuated the inhibitory action produced by all doses of nicotine on BK- or PAF-induced plasma extravasation, suggesting the contribution of endogenous opioids. 3. RU-38,486 (a glucocorticoid receptor antagonist) (30 mg kg-1, s.c.), and metyrapone (a glucocorticoid synthesis inhibitor) (two hourly injections of 100 mg kg-1, i.p.) both attenuated the action of high-dose nicotine without affecting that of low-dose nicotine. 4. Spinal mecamylamine (a nicotinic receptor antagonist) (0.025 mg kg-1, intrathecally, i.t.) attenuated the action of high-dose, but not low-dose, nicotine, suggesting that part of the action of high-dose nicotine is mediated by spinal nicotinic receptors. 5. Combined treatment with ICI-118,551, naloxone and RU-38,486 attenuated the action of low-dose nicotine by an amount similar to that produced by naloxone alone but produced significantly greater attenuation of the effect of high-dose nicotine when compared to the action of any of the three antagonists alone.

Combination of antagonistic yeasts with two food additives for control of brown rot caused by Monilinia fructicola on sweet cherry fruit.

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Qin, G Z; Tian, S P; Xu, Y; Chan, Z L; Li, B Q

2006-03-01

To evaluate beneficial effect of two food additives, ammonium molybdate (NH4-Mo) and sodium bicarbonate (NaBi), on antagonistic yeasts for control of brown rot caused by Monilinia fructicola in sweet cherry fruit under various storage conditions. The mechanisms of action by which food additives enhance the efficacy of antagonistic yeasts were also evaluated. Biocontrol activity of Pichia membranefaciens and Cryptococcus laurentii against brown rot in sweet cherry fruit was improved by addition of 5 mmol l(-1) NH4-Mo or 2% NaBi when stored in air at 20 and 0 degrees C, and in controlled atmosphere (CA) storage with 10% O2 + 10% CO2 at 0 degrees C. Population dynamics of P. membranefaciens in the wounds of fruit were inhibited by NH4-Mo at 20 degrees C after 1 day of incubation and growth of C. laurentii was inhibited by NH4-Mo at 0 degrees C in CA storage after 60 days. In contrast, NaBi did not significantly influence growth of the two yeasts in fruit wounds under various storage conditions except that the growth of P. membranefaciens was stimulated after storage for 45 days at 0 degrees C in CA storage. When used alone, the two additives showed effective control of brown rot in sweet cherry fruit and the efficacy was closely correlated with the concentrations used. The result of in vitro indicated that growth of M. fructicola was significantly inhibited by NH4-Mo and NaBi. Application of additives improved biocontrol of brown rot on sweet cherry fruit under various storage conditions. It is postulated that the enhancement of disease control is directly because of the inhibitory effects of additives on pathogen growth, and indirectly because of the relatively little influence of additives on the growth of antagonistic yeasts. The results obtained in this study suggest that an integration of NH4-Mo or NaBi with biocontrol agents has great potential in commercial management of postharvest diseases of fruit.

Competition assays and physiological experiments of soil and phyllosphere yeasts identify Candida subhashii as a novel antagonist of filamentous fungi.

Science.gov (United States)

Hilber-Bodmer, Maja; Schmid, Michael; Ahrens, Christian H; Freimoser, Florian M

2017-01-05

While recent advances in next generation sequencing technologies have enabled researchers to readily identify countless microbial species in soil, rhizosphere, and phyllosphere microbiomes, the biological functions of the majority of these species are unknown. Functional studies are therefore urgently needed in order to characterize the plethora of microorganisms that are being identified and to point out species that may be used for biotechnology or plant protection. Here, we used a dual culture assay and growth analyses to characterise yeasts (40 different isolates) and their antagonistic effect on 16 filamentous fungi; comprising plant pathogens, antagonists, and saprophytes. Overall, this competition screen of 640 pairwise combinations revealed a broad range of outcomes, ranging from small stimulatory effects of some yeasts up to a growth inhibition of more than 80% by individual species. On average, yeasts isolated from soil suppressed filamentous fungi more strongly than phyllosphere yeasts and the antagonistic activity was a species-/isolate-specific property and not dependent on the filamentous fungus a yeast was interacting with. The isolates with the strongest antagonistic activity were Metschnikowia pulcherrima, Hanseniaspora sp., Cyberlindnera sargentensis, Aureobasidium pullulans, Candida subhashii, and Pichia kluyveri. Among these, the soil yeasts (C. sargentensis, A. pullulans, C. subhashii) assimilated and/or oxidized more di-, tri- and tetrasaccharides and organic acids than yeasts from the phyllosphere. Only the two yeasts C. subhashii and M. pulcherrima were able to grow with N-acetyl-glucosamine as carbon source. The competition assays and physiological experiments described here identified known antagonists that have been implicated in the biological control of plant pathogenic fungi in the past, but also little characterised species such as C. subhashii. Overall, soil yeasts were more antagonistic and metabolically versatile than yeasts from

Reciprocal inhibition between motor neurons of the tibialis anterior and triceps surae in humans.

Science.gov (United States)

Yavuz, Utku Ş; Negro, Francesco; Diedrichs, Robin; Farina, Dario

2018-05-01

Motor neurons innervating antagonist muscles receive reciprocal inhibitory afferent inputs to facilitate the joint movement in the two directions. The present study investigates the mutual transmission of reciprocal inhibitory afferent inputs between the tibialis anterior (TA) and triceps surae (soleus and medial gastrocnemius) motor units. We assessed this mutual mechanism in large populations of motor units for building a statistical distribution of the inhibition amplitudes during standardized input to the motor neuron pools to minimize the effect of modulatory pathways. Single motor unit activities were identified using high-density surface electromyography (HDsEMG) recorded from the TA, soleus (Sol), and medial gastrocnemius (GM) muscles during isometric dorsi- and plantarflexion. Reciprocal inhibition on the antagonist muscle was elicited by electrical stimulation of the tibial (TN) or common peroneal nerves (CPN). The probability density distributions of reflex strength for each muscle were estimated to examine the strength of mutual transmission of reciprocal inhibitory input. The results showed that the strength of reciprocal inhibition in the TA motor units was fourfold greater than for the GM and the Sol motor units. This suggests an asymmetric transmission of reciprocal inhibition between ankle extensor and flexor muscles. This asymmetry cannot be explained by differences in motor unit type composition between the investigated muscles since we sampled low-threshold motor units in all cases. Therefore, the differences observed for the strength of inhibition are presumably due to a differential reciprocal spindle afferent input and the relative contribution of nonreciprocal inhibitory pathways. NEW & NOTEWORTHY We investigated the mutual transmission of reciprocal inhibition in large samples of motor units using a standardized input (electrical stimulation) to the motor neurons. The results demonstrated that the disynaptic reciprocal inhibition exerted

MIBE acts as antagonist ligand of both estrogen receptor α and GPER in breast cancer cells.

Science.gov (United States)

Lappano, Rosamaria; Santolla, Maria Francesca; Pupo, Marco; Sinicropi, Maria Stefania; Caruso, Anna; Rosano, Camillo; Maggiolini, Marcello

2012-01-17

progression. Hence, the simultaneous inhibition of both ERα and GPER may guarantee major therapeutic benefits in respect to the use of a selective estrogen receptor antagonist.

Design, synthesis, and evaluation of nonretinoid retinol binding protein 4 antagonists for the potential treatment of atrophic age-related macular degeneration and Stargardt disease.

Science.gov (United States)

Cioffi, Christopher L; Dobri, Nicoleta; Freeman, Emily E; Conlon, Michael P; Chen, Ping; Stafford, Douglas G; Schwarz, Daniel M C; Golden, Kathy C; Zhu, Lei; Kitchen, Douglas B; Barnes, Keith D; Racz, Boglarka; Qin, Qiong; Michelotti, Enrique; Cywin, Charles L; Martin, William H; Pearson, Paul G; Johnson, Graham; Petrukhin, Konstantin

2014-09-25

Accumulation of lipofuscin in the retina is associated with pathogenesis of atrophic age-related macular degeneration and Stargardt disease. Lipofuscin bisretinoids (exemplified by N-retinylidene-N-retinylethanolamine) seem to mediate lipofuscin toxicity. Synthesis of lipofuscin bisretinoids depends on the influx of retinol from serum to the retina. Compounds antagonizing the retinol-dependent interaction of retinol-binding protein 4 (RBP4) with transthyretin in the serum would reduce serum RBP4 and retinol and inhibit bisretinoid formation. We recently showed that A1120 (3), a potent carboxylic acid based RBP4 antagonist, can significantly reduce lipofuscin bisretinoid formation in the retinas of Abca4(-/-) mice. As part of the NIH Blueprint Neurotherapeutics Network project we undertook the in vitro exploration to identify novel conformationally flexible and constrained RBP4 antagonists with improved potency and metabolic stability. We also demonstrate that upon acute and chronic dosing in rats, 43, a potent cyclopentyl fused pyrrolidine antagonist, reduced circulating plasma RBP4 protein levels by approximately 60%.

Adenosine A2A receptors modulate the dopamine D2 receptor-mediated inhibition of synaptic transmission in the mouse prefrontal cortex.

Science.gov (United States)

Real, Joana I; Simões, Ana Patrícia; Cunha, Rodrigo A; Ferreira, Samira G; Rial, Daniel

2018-05-01

Prefrontal cortex (PFC) circuits are modulated by dopamine acting on D 1 - and D 2 -like receptors, which are pharmacologically exploited to manage neuropsychiatric conditions. Adenosine A 2A receptors (A 2 A R) also control PFC-related responses and A 2 A R antagonists are potential anti-psychotic drugs. As tight antagonistic A 2 A R-D 2 R and synergistic A 2 A R-D 1 R interactions occur in other brain regions, we now investigated the crosstalk between A 2 A R and D 1 /D 2 R controlling synaptic transmission between layers II/III and V in mouse PFC coronal slices. Dopamine decreased synaptic transmission, a presynaptic effect based on the parallel increase in paired-pulse responses. Dopamine inhibition was prevented by the D 2 R-like antagonist sulpiride but not by the D 1 R antagonist SCH23390 and was mimicked by the D 2 R agonist sumanirole, but not by the agonists of either D 4 R (A-412997) or D 3 R (PD128907). Dopamine inhibition was prevented by the A 2 A R antagonist, SCH58261, and attenuated in A 2 A R knockout mice. Accordingly, triple-labelling immunocytochemistry experiments revealed the co-localization of A 2 A R and D 2 R immunoreactivity in glutamatergic (vGluT1-positive) nerve terminals of the PFC. This reported positive A 2 A R-D 2 R interaction controlling PFC synaptic transmission provides a mechanistic justification for the anti-psychotic potential of A 2 A R antagonists. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

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

Science.gov (United States)

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

1998-05-08

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

Identification of poly(ADP-ribose) polymerase-1 as the OXPHOS-generated ATP sensor of nuclei of animal cells

International Nuclear Information System (INIS)

Kun, Ernest; Kirsten, Eva; Hakam, Alaeddin; Bauer, Pal I.; Mendeleyev, Jerome

2008-01-01

Our results show that in the intact normal animal cell mitochondrial ATP is directly connected to nuclear PARP-1 by way of a specific adenylate kinase enzymatic path. This mechanism is demonstrated in two models: (a) by its inhibition with a specific inhibitor of adenylate kinase, and (b) by disruption of ATP synthesis through uncoupling of OXPHOS. In each instance the de-inhibited PARP-1 is quantitatively determined by enzyme kinetics. The nuclear binding site of PARP-1 is Topo I, and is identified as a critical 'switchpoint' indicating the nuclear element that connects OXPHOS with mRNA synthesis in real time. The mitochondrial-nuclear PARP-1 pathway is not operative in cancer cells

Deciphering hierarchical features in the energy landscape of adenylate kinase folding/unfolding

Science.gov (United States)

Taylor, J. Nicholas; Pirchi, Menahem; Haran, Gilad; Komatsuzaki, Tamiki

2018-03-01

Hierarchical features of the energy landscape of the folding/unfolding behavior of adenylate kinase, including its dependence on denaturant concentration, are elucidated in terms of single-molecule fluorescence resonance energy transfer (smFRET) measurements in which the proteins are encapsulated in a lipid vesicle. The core in constructing the energy landscape from single-molecule time-series across different denaturant concentrations is the application of rate-distortion theory (RDT), which naturally considers the effects of measurement noise and sampling error, in combination with change-point detection and the quantification of the FRET efficiency-dependent photobleaching behavior. Energy landscapes are constructed as a function of observation time scale, revealing multiple partially folded conformations at small time scales that are situated in a superbasin. As the time scale increases, these denatured states merge into a single basin, demonstrating the coarse-graining of the energy landscape as observation time increases. Because the photobleaching time scale is dependent on the conformational state of the protein, possible nonequilibrium features are discussed, and a statistical test for violation of the detailed balance condition is developed based on the state sequences arising from the RDT framework.

Antagonistic control of social versus repetitive self-grooming behaviors by separable amygdala neuronal subsets.

Science.gov (United States)

Hong, Weizhe; Kim, Dong-Wook; Anderson, David J

2014-09-11

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. Copyright © 2014 Elsevier Inc. All rights reserved.

Pharmacological profiling an abundantly expressed schistosome serotonergic GPCR identifies nuciferine as a potent antagonist

Directory of Open Access Journals (Sweden)

John D. Chan

2016-12-01

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.

In vitro mutagenesis studies at the arginine residues of adenylate kinase. A revised binding site for AMP in the X-ray-deduced model

International Nuclear Information System (INIS)

Kim, Hyo Joon; Nishikawa, Satoshi; Tokutomi, Yuiko; Uesugi, Seiichi; Takenaka, Hitoshi; Hamada, Minoru; Kuby, S.A.

1990-01-01

Although X-ray crystallographic and NMR studies have been made on the adenylate kinases, the substrate-binding sites are not unequivocally established. In an attempt to shed light on the binding sites for MgATP 2- and for AMP 2- in human cytosolic adenylate kinase, the authors have investigated the enzymic effects of replacement of the arginine residues, which had been assumed by Pai et al. to interact with the phosphoryl groups of AMP 2- and MgATP 2- . With use of the site-directed mutagenesis method, point mutations were made in the artificial gene for hAK1 to replace these arginine residues with alanyl residues and yield the mutants R44A hAK1, R132A hAK1, R138A hAK1, and R149A hAK1. The resulting large increases in the K m,app values for AMP 2- of the mutant enzymes, the relatively small increases in the K m,app values for MgATP 2- , and the fact that the R132A, R138A, and R149A mutant enzymes proved to be very poor catalysts are consistent with the idea that the assigned substrate binding sites of Pai et al. have been reversed and that their ATP-binding site may be assigned as the AMP site

Piroxicam inhibits NMDA receptor-mediated excitotoxicity through allosteric inhibition of the GluN2B subunit: an in silico study elucidating a novel mechanism of action of the drug.

Science.gov (United States)

Mazumder, Muhammed Khairujjaman; Borah, Anupom

2014-12-01

Hyperactivation of GluN2B subunit containing N-methyl-d-aspartate receptors (NMDARs) significantly contributes to the development of several neurodegenerative diseases through a process called excitotoxicity. NMDARs are voltage-gated Ca2+ channels which when activated lead to excessive influx of Ca2+ into neurons thereby exacerbating several calcium-dependent pathways that cause oxidative stress and apoptosis. Several drugs are presently in use to counter the NMDAR-mediated excitotoxic events among which Ifenprodil and its derivatives are GluN2B selective allosteric antagonists. Certain non-steroidal anti-inflammatory drugs (NSAIDs) have also been reported to inhibit NMDARs and the resultant pathologies. Meanwhile, Piroxicam, which is a NSAID, has been reported to be protective in cerebral ischemia-induced neurodegeneration through various pathways. Since Piroxicam has more number of interacting groups as compared to other NSAIDs and also has structural similarities with Ifenprodil, we thought it prudent that Piroxicam may inhibit NMDARs similar to Ifenprodil. By using molecular docking as a tool, we validated the hypothesis and hereby report for the first time that Piroxicam can inhibit GluN2B containing NMDARs through allosteric mode similar to the well known selective antagonist--Ifenprodil; and thus can be a therapeutic drug for the prevention of excitotoxic neurodegeneration. Copyright © 2014 Elsevier Ltd. All rights reserved.

m-Acetylanilido-GTP, a novel photoaffinity label for GTP-binding proteins: synthesis and application.

OpenAIRE

Zor, T; Halifa, I; Kleinhaus, S; Chorev, M; Selinger, Z

1995-01-01

A novel photoaffinity label, m-acetylanilido-GTP (m-AcAGTP), was synthesized and used to identify GTP-binding proteins (G-proteins). This GTP analogue is easily prepared and can be used for photoaffinity labelling of G-proteins without chromatographic purification. In the presence of the beta-adrenergic agonist isoprenaline, it activates turkey erythrocyte adenylate cyclase. This activation persists even when the beta-adrenergic receptor is subsequently blocked by antagonist, indicating that ...

Effect of bradykinin antagonists on bradykinin-induced plasma extravasation, venoconstriction, prostaglandin E2 release, nociceptor stimulation and contraction of the iris sphincter muscle in the rabbit.

Science.gov (United States)

Griesbacher, T.; Lembeck, F.

1987-01-01

1 The inhibition of the bradykinin-induced plasma extravasation by six bradykinin (Bk) antagonists was tested on rabbit skin. All of them showed inhibitory effects without an agonistic action in the does used. B4310 (Lys-Lys-3-Hyp-5,8-Thi-7-DPhe-Bk) was the most active antagonist and was therefore used in the subsequent experiments. 2 B4310 (5-500 nM) antagonized the bradykinin-induced reduction of the venous outflow from the rabbit isolated ear in dose-dependent manner without affecting the arterial vasoconstriction induced by angiotensin II. 3 The bradykinin-induced release of prostaglandin E2 (PGE2) from the perfused rabbit ear was reduced by 63% when B4310 (800 nM) was infused before, during and after the bradykinin injection. 4 Bradykinin was injected into the ear artery of anaesthetized rabbits and the reflex hypotensive response was used as indicator of the nociception. The response was antagonized by a local infusion of B4310 (50 and 500 nM). The antagonism was dose-dependent and reversible. The parallel shift of the dose-response curve to bradykinin suggests a competitive inhibition. However, B4310 did not antagonize acetylcholine-induced nociceptor stimulation. 5 B4310 inhibited bradykinin-induced stimulation of the trigeminal nerve which results in a substance P-mediated contraction of the iris sphincter muscle. A pA2 of 7.59 was calculated. B4310 did not inhibit capsaicin-induced contractions. 6 It is concluded that B4310 inhibits specifically five different actions of bradykinin which are related to its possible pathophysiological role. PMID:3479223

Current position of 5HT3 antagonists and the additional value of NK1 antagonists; a new class of antiemetics

NARCIS (Netherlands)

R. de Wit (Ronald)

2003-01-01

textabstractThe advent of the 5HT3 receptor antagonists (5HT3 antagonists) in the 1990s and the combination with dexamethasone has resulted in acute emesis protection in 70% of patients receiving highly emetogenic chemotherapy. Despite complete protection in the acute phase, however, 40% of patients

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

1992-01-01

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.

Opioid antagonists with minimal sedation for opioid withdrawal.

Science.gov (United States)

Gowing, Linda; Ali, Robert; White, Jason M

2017-05-29

Managed withdrawal is a necessary step prior to drug-free treatment or as the endpoint of long-term substitution treatment. To assess the effects of opioid antagonists plus minimal sedation for opioid withdrawal. Comparators were placebo as well as more established approaches to detoxification, such as tapered doses of methadone, adrenergic agonists, buprenorphine and symptomatic medications. We updated our searches of the following databases to December 2016: CENTRAL, MEDLINE, Embase, PsycINFO and Web of Science. We also searched two trials registers and checked the reference lists of included studies for further references to relevant studies. We included randomised and quasi-randomised controlled clinical trials along with prospective controlled cohort studies comparing opioid antagonists plus minimal sedation versus other approaches or different opioid antagonist regimens for withdrawal in opioid-dependent participants. We used standard methodological procedures expected by Cochrane. Ten studies (6 randomised controlled trials and 4 prospective cohort studies, involving 955 participants) met the inclusion criteria for the review. We considered 7 of the 10 studies to be at high risk of bias in at least one of the domains we assessed.Nine studies compared an opioid antagonist-adrenergic agonist combination versus a treatment regimen based primarily on an alpha 2 -adrenergic agonist (clonidine or lofexidine). Other comparisons (placebo, tapered doses of methadone, buprenorphine) made by included studies were too diverse for any meaningful analysis. This review therefore focuses on the nine studies comparing an opioid antagonist (naltrexone or naloxone) plus clonidine or lofexidine versus treatment primarily based on clonidine or lofexidine.Five studies took place in an inpatient setting, two studies were in outpatients with day care, two used day care only for the first day of opioid antagonist administration, and one study described the setting as outpatient

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

Directory of Open Access Journals (Sweden)

Sinar David Granada García

2014-09-01

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.

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

2016-01-01

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...

Antagonistic Activity of Trichoderma ISolates against Sclerotium rolfsii : Screening of Efficient Isolates from Morocco Soils for Biological Control

Directory of Open Access Journals (Sweden)

N. Khattabi

2004-12-01

Full Text Available Seventy Trichoderma spp. isolates collected from different regions of Morocco were tested for their capacity to inhibit in vitro mycelial growth of Sclerotium rolfsii, and for their effect on the viability of S. rolfsii sclerotia in the soil. The Trichoderma spp. isolates inhibited mycelial growth of S. rolfsii to various degrees, with 52% of isolates expressing an average inhibition, varying between 45 and 55%. The effect on the viability of sclerotia in the soil also varied between isolates of Trichoderma, with the majority (84% having a slight effect. A group of twenty isolates identified as Trichoderma harzianum when tested in sterilized soil, significantly reduced sclerotial viability though not in natural soil. Four of these isolates (Nz, Kb2, Kb3 and Kf1 showed good antagonistic activity against S. rolfsii and were also highly competitive in natural soil. These isolates would therefore be candidates for development in biological control program.

In-vitro effect of estrogen-antagonist on motility and penetration ability of human spermatozoa.

Science.gov (United States)

Allag, I S; Rangari, K

1997-08-01

Antiestrogens affect spermatozoa through their action on Leydig and Sertoli cells. Direct effect of antiestrogens namely tamoxifen and centchroman in concentration of 1, 2.5, 5, 10 and 20 micrograms/ml in incubation medium was determined on motility and penetration ability of human spermatozoa. Motility (%) was invariably reduced after 15, 30 and 60 min. of incubation. Addition of 17 beta-estradiol to medium with antagonist caused inhibition of motility in dose related manner. The distance travelled by spermatozoa treated with tamoxifen or centchroman in media was reduced by 30% and addition of estradiol along with antiestrogen reduced it to 50% compared to that of untreated spermatozoa.

A new and specific non-NMDA receptor antagonist, FG 9065, blocks L-AP4-evoked depolarization in rat cerebral cortex.

Science.gov (United States)

Sheardown, M J

1988-04-13

L(+)-AP4 (2-amino-4-phosphonobutyrate) depolarized slices of rat cerebral cortex, when applied following a 2 min priming application of quisqualate. This response diminishes with time and is not seen after NMDA application. A new selective non-N-methyl-D-aspartate (NMDA) antagonist, 6-cyano-7-nitro-2,3-dihydroxyquinoxaline (FG 9065), inhibits the L(+)-AP4 depolarization. It is argued that the response is mediated indirectly by postsynaptic quisqualate receptors.

Combination decongestion therapy in hospitalized heart failure: loop diuretics, mineralocorticoid receptor antagonists and vasopressin antagonists.

Science.gov (United States)

Vaduganathan, Muthiah; Mentz, Robert J; Greene, Stephen J; Senni, Michele; Sato, Naoki; Nodari, Savina; Butler, Javed; Gheorghiade, Mihai

2015-01-01

Congestion is the most common reason for admissions and readmissions for heart failure (HF). The vast majority of hospitalized HF patients appear to respond readily to loop diuretics, but available data suggest that a significant proportion are being discharged with persistent evidence of congestion. Although novel therapies targeting congestion should continue to be developed, currently available agents may be utilized more optimally to facilitate complete decongestion. The combination of loop diuretics, natriuretic doses of mineralocorticoid receptor antagonists and vasopressin antagonists represents a regimen of currently available therapies that affects early and persistent decongestion, while limiting the associated risks of electrolyte disturbances, hemodynamic fluctuations, renal dysfunction and mortality.

Dual antagonists of integrins.

Science.gov (United States)

Nadrah, K; Dolenc, M Sollner

2005-01-01

The roles of integrins in pathologies have been studied intensively and only partially explained. This has resulted in the development of several nanomolar antagonists to certain integrins. In most cases, the aim was to produce compounds which are highly selective towards specific integrins. This paradigm has recently shifted a little. Targeting two or more integrins with one compound has become a very attractive concept, especially since it has become clear that several severe disorders, such as pathological angiogenesis, cannot be treated just with highly specific integrin antagonists. This review is aimed to elucidate some aspects regarding the design of drugs with dual activity towards integrins. Integrin structure and tissue distribution will first be described, in order to provide the basis for their functions in various pathologies which will follow. Inhibitors of several pairs of integrins will be described.

The effect of different classes of beta-antagonists on clinical and experimental hypertension.

Science.gov (United States)

Fitzgerald, J D

1982-01-01

The reference beta adrenoceptor antagonist propranolol reduces blood pressure in about 60% of patients with essential hypertension. Pressure is reduced in the supine, and erect positions without postural hypotension as well as during exercise. The average extent of pressure reduction is approximately 26/16 mm.Hg. Though all clinically available beta antagonists reduce blood pressure, the profile may be modified by both adrenotropic and non-adrenotropic ancillary properties. Of the adrenotropic properties, potency influences dose frequency and total body burden of drug. Selective beta 1 antagonism may enhance safety without reducing efficacy in patients with obstructive airways disease. Selective beta 2 blockade does not reduce blood pressure in experimental models or normal subjects, but the response in patients is unknown. Partial agonism may reduce efficacy if the degree of stimulant activity is too great. Of the non-adrenotropic properties, membrane stabilising properties are of relevance only in so far as such agents undergo extensive biotransformation resulting in either reduced efficacy when drugs are used at fixed doses or the formation of biologically active metabolites. The additional properties of either alpha adrenergic blockade or inhibition of vascular smooth muscle tone modify both the speed of onset and the haemodynamic profile. The interaction of these ancillary pharmacological properties is evaluated in this review.

A homolog of the vertebrate pituitary adenylate cyclase-activating polypeptide is both necessary and instructive for the rapid formation of associative memory in an invertebrate

OpenAIRE

Pirger, Zsolt; László, Zita; Kemenes, Ildikó; Tóth, Gábor; Reglődi, Dóra; Kemenes, György

2010-01-01

Similar to other invertebrate and vertebrate animals, cAMP dependent signaling cascades are key components of long-term memory (LTM) formation in the snail Lymnaea stagnalis, an established experimental model for studying evolutionarily conserved molecular mechanisms of long-term associative memory. Although a great deal is already known about the signaling cascades activated by cAMP, the molecules involved in the learning-induced activation of adenylate cyclase (AC) in Lymnaea remained unkno...

Inhibition coefficient and molecular diversity of multi stress tolerant Trichoderma as potential biocontrol agent against Sclerotium rolfsii Sacc.

Science.gov (United States)

Hirpara, Darshna G; Gajera, H P; Hirapara, Jaydeep G; Golakiya, B A

2017-11-01

Trichoderma is one of the most exploited biocontrol agent for the management of plant diseases. Twenty strains of Trichoderma (six of T. harzianum, four of T. viride, three of T. virens, three of T. koningii, each one of T. hamatum, T. reesei, T. parceramosum and Trichoderma spp.) subjected to in vitro antagonism up to 12days after inoculation against Sclerotium rolfsii Sacc. causing stem rot in groundnut. A new concept was developed to determine inhibition coefficient representing pathogen biology and biocontrol related biophysical variables. Results explained differential inhibition coefficient of test pathogen by Trichoderma antagonists. The inhibition coefficient of test pathogen was examined highest (91.13%) by T. virens NBAII Tvs12 followed by T. virens MTCC 794 (89.33%) and T. koningii MTCC 796 (62.39%). Microscopic study confirmed biocontrol mechanism as mycoparasitism for Tvs12 and antibiosis for T. koningii MTCC 796. The sclerotial biogenesis of test pathogen was elevated during weak antagonism and diminished in interactions with strong antagonists. The inhibition coefficient of S. rolfsii was significantly negatively correlated with sclerotia formation and lipid peroxidation during the antagonism. Trichoderma strains were screened for fungicides (carbendazim and tebuconazole, thiram and mancozeb) and abiotic stress (drought and salt) tolerance. Results indicated that T. koningii MTCC 796 efficiently grew better than the other strains with maximum radial growth under adverse conditions. The genetic variability among the Trichoderma was determined using 34 gene specific markers which amplified 146 alleles. The SSR similarities explained substantial diversity (15 to 87%) across Trichoderma strains and pathogen S. rolfsii. Principal coordinates analysis (PCA) were comparable to the cluster analysis and first three most informative PC components explained 64.45% of the total variation. In PCA, potent antagonists appear to be distinct from other strains. Five

The role of the C8 proton of ATP in the catalysis of shikimate kinase and adenylate kinase

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Kenyon Colin P

2012-08-01

Full Text Available Abstract Background It has been demonstrated that the adenyl moiety of ATP plays a direct role in the regulation of ATP binding and/or phosphoryl transfer within a range of kinase and synthetase enzymes. The role of the C8-H of ATP in the binding and/or phosphoryl transfer on the enzyme activity of a number of kinase and synthetase enzymes has been elucidated. The intrinsic catalysis rate mediated by each kinase enzyme is complex, yielding apparent KM values ranging from less than 0.4 μM to more than 1 mM for ATP in the various kinases. Using a combination of ATP deuterated at the C8 position (C8D-ATP as a molecular probe with site directed mutagenesis (SDM of conserved amino acid residues in shikimate kinase and adenylate kinase active sites, we have elucidated a mechanism by which the ATP C8-H is induced to be labile in the broader kinase family. We have demonstrated the direct role of the C8-H in the rate of ATP consumption, and the direct role played by conserved Thr residues interacting with the C8-H. The mechanism by which the vast range in KM might be achieved is also suggested by these findings. Results We have demonstrated the mechanism by which the enzyme activities of Group 2 kinases, shikimate kinase (SK and adenylate kinase 1 (AK1, are controlled by the C8-H of ATP. Mutations of the conserved threonine residues associated with the labile C8-H cause the enzymes to lose their saturation kinetics over the concentration range tested. The relationship between the role C8-H of ATP in the reaction mechanism and the ATP concentration as they influence the saturation kinetics of the enzyme activity is also shown. The SDM clearly identified the amino acid residues involved in both the catalysis and regulation of phosphoryl transfer in SK and AK1 as mediated by C8H-ATP. Conclusions The data outlined serves to demonstrate the “push” mechanism associated with the control of the saturation kinetics of Group 2 kinases mediated by ATP C8-H. It

Structure of the d-alanylgriseoluteic acid biosynthetic protein EhpF, an atypical member of the ANL superfamily of adenylating enzymes

International Nuclear Information System (INIS)

Bera, Asim K.; Atanasova, Vesna; Gamage, Swarna; Robinson, Howard; Parsons, James F.

2010-01-01

The structure of EhpF from P. agglomerans has been solved alone and in complex with phenazine-1,6-dicarboxylate. Apo EhpF was solved and refined in two different space groups at 1.95 and 2.3 Å resolution and the EhpF–phenazine-1,6-dicarboxylate complex structure was determined at 2.8 Å resolution. The structure of EhpF, a 41 kDa protein that functions in the biosynthetic pathway leading to the broad-spectrum antimicrobial compound d-alanylgriseoluteic acid (AGA), is reported. A cluster of approximately 16 genes, including ehpF, located on a 200 kbp plasmid native to certain strains of Pantoea agglomerans encodes the proteins that are required for the conversion of chorismic acid to AGA. Phenazine-1,6-dicarboxylate has been identified as an intermediate in AGA biosynthesis and deletion of ehpF results in accumulation of this compound in vivo. The crystallographic data presented here reveal that EhpF is an atypical member of the acyl-CoA synthase or ANL superfamily of adenylating enzymes. These enzymes typically catalyze two-step reactions involving adenylation of a carboxylate substrate followed by transfer of the substrate from AMP to coenzyme A or another phosphopantetheine. EhpF is distinguished by the absence of the C-terminal domain that is characteristic of enzymes from this family and is involved in phosphopantetheine binding and in the second half of the canonical two-step reaction that is typically observed. Based on the structure of EhpF and a bioinformatic analysis, it is proposed that EhpF and EhpG convert phenazine-1,6-dicarboxylate to 6-formylphenazine-1-carboxylate via an adenylyl intermediate

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

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Dan Song

2014-01-01

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.

Oral tremor induced by the muscarinic agonist pilocarpine is suppressed by the adenosine A2A antagonists MSX-3 and SCH58261, but not the adenosine A1 antagonist DPCPX.

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Collins, Lyndsey E; Galtieri, Daniel J; Brennum, Lise T; Sager, Thomas N; Hockemeyer, Jörg; Müller, Christa E; Hinman, James R; Chrobak, James J; Salamone, John D

2010-02-01

Tremulous jaw movements in rats, which can be induced by dopamine (DA) antagonists, DA depletion, and cholinomimetics, have served as a useful model for studies of tremor. Although adenosine A(2A) antagonists can reduce the tremulous jaw movements induced by DA antagonists and DA depletion, there are conflicting reports about the interaction between adenosine antagonists and cholinomimetic drugs. The present studies investigated the ability of adenosine antagonists to reverse the tremorogenic effect of the muscarinic agonist pilocarpine. While the adenosine A(2A) antagonist MSX-3 was incapable of reversing the tremulous jaw movements induced by the 4.0mg/kg dose of pilocarpine, both MSX-3 and the adenosine A(2A) antagonist SCH58261 reversed the tremulous jaw movements elicited by 0.5mg/kg pilocarpine. Systemic administration of the adenosine A(1) antagonist DPCPX failed to reverse the tremulous jaw movements induced by either an acute 0.5mg/kg dose of the cholinomimetic pilocarpine or the DA D2 antagonist pimozide, indicating that the tremorolytic effects of adenosine antagonists may be receptor subtype specific. Behaviorally active doses of MSX-3 and SCH 58261 showed substantial in vivo occupancy of A(2A) receptors, but DPCPX did not. The results of these studies support the use of adenosine A(2A) antagonists for the treatment of tremor. Copyright 2009 Elsevier Inc. All rights reserved.

Inhibition of MAP kinase promotes the recruitment of corepressor SMRT by tamoxifen-bound estrogen receptor alpha and potentiates tamoxifen action in MCF-7 cells

International Nuclear Information System (INIS)

Hong, Wei; Chen, Linfeng; Li, Juan; Yao, Zhi

2010-01-01

Estrogen receptor alpha (ERα), a ligand controlled transcription factor, plays an important role in breast cancer growth and endocrine therapy. Tamoxifen (TAM) antagonizes ERα activity and has been applied in breast cancer treatment. TAM-bound ERα associates with nuclear receptor-corepressors. Mitogen-activated protein kinase (MAPK) has been elucidated to result in cross-talk between growth factor and ERα mediated signaling. We show that activated MAPK represses interaction of TAM-bound ERα with silencing mediator for retinoid and thyroid hormone receptors (SMRT) and inhibits the recruitment of SMRT by ERα to certain estrogen target genes. Blockade of MAPK signaling cascade with MEK inhibitor U0126 promotes the interaction and subsequently inhibits ERα activity via enhanced recruitment of SMRT, leading to reduced expression of ERα target genes. The growth rate of MCF-7 cells was decelerated when treated with both TAM and U0126. Moreover, the growth of MCF-7 cells stably expressing SMRT showed a robust repression in the presence of TAM and U0126. These results suggest that activated MAPK signaling cascade attenuates antagonist-induced recruitment of SMRT to ERα, suggesting corepressor mediates inhibition of ERα transactivation and breast cancer cell growth by antagonist. Taken together, our finding indicates combination of antagonist and MAPK inhibitor could be a helpful approach for breast cancer therapy.

Adaptation of an L-proline adenylation domain to use 4-propyl-L-proline in the evolution of lincosamide biosynthesis.

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Stanislav Kadlčík

Full Text Available Clinically used lincosamide antibiotic lincomycin incorporates in its structure 4-propyl-L-proline (PPL, an unusual amino acid, while celesticetin, a less efficient related compound, makes use of proteinogenic L-proline. Biochemical characterization, as well as phylogenetic analysis and homology modelling combined with the molecular dynamics simulation were employed for complex comparative analysis of the orthologous protein pair LmbC and CcbC from the biosynthesis of lincomycin and celesticetin, respectively. The analysis proved the compared proteins to be the stand-alone adenylation domains strictly preferring their own natural substrate, PPL or L-proline. The LmbC substrate binding pocket is adapted to accommodate a rare PPL precursor. When compared with L-proline specific ones, several large amino acid residues were replaced by smaller ones opening a channel which allowed the alkyl side chain of PPL to be accommodated. One of the most important differences, that of the residue corresponding to V306 in CcbC changing to G308 in LmbC, was investigated in vitro and in silico. Moreover, the substrate binding pocket rearrangement also allowed LmbC to effectively adenylate 4-butyl-L-proline and 4-pentyl-L-proline, substrates with even longer alkyl side chains, producing more potent lincosamides. A shift of LmbC substrate specificity appears to be an integral part of biosynthetic pathway adaptation to the PPL acquisition. A set of genes presumably coding for the PPL biosynthesis is present in the lincomycin--but not in the celesticetin cluster; their homologs are found in biosynthetic clusters of some pyrrolobenzodiazepines (PBD and hormaomycin. Whereas in the PBD and hormaomycin pathways the arising precursors are condensed to another amino acid moiety, the LmbC protein is the first functionally proved part of a unique condensation enzyme connecting PPL to the specialized amino sugar building unit.

Inhibition by TRPA1 agonists of compound action potentials in the frog sciatic nerve

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Matsushita, Akitomo; Ohtsubo, Sena; Fujita, Tsugumi; Kumamoto, Eiichi, E-mail: kumamote@cc.saga-u.ac.jp

2013-04-26

Highlights: •TRPA1 agonists inhibited compound action potentials in frog sciatic nerves. •This inhibition was not mediated by TRPA1 channels. •This efficacy was comparable to those of lidocaine and cocaine. •We found for the first time an ability of TRPA1 agonists to inhibit nerve conduction. -- Abstract: Although TRPV1 and TRPM8 agonists (vanilloid capsaicin and menthol, respectively) at high concentrations inhibit action potential conduction, it remains to be unknown whether TRPA1 agonists have a similar action. The present study examined the actions of TRPA1 agonists, cinnamaldehyde (CA) and allyl isothiocyanate (AITC), which differ in chemical structure from each other, on compound action potentials (CAPs) recorded from the frog sciatic nerve by using the air-gap method. CA and AITC concentration-dependently reduced the peak amplitude of the CAP with the IC{sub 50} values of 1.2 and 1.5 mM, respectively; these activities were resistant to a non-selective TRP antagonist ruthenium red or a selective TRPA1 antagonist HC-030031. The CA and AITC actions were distinct in property; the latter but not former action was delayed in onset and partially reversible, and CA but not AITC increased thresholds to elicit CAPs. A CAP inhibition was seen by hydroxy-α-sanshool (by 60% at 0.05 mM), which activates both TRPA1 and TRPV1 channels, a non-vanilloid TRPV1 agonist piperine (by 20% at 0.07 mM) and tetrahydrolavandulol (where the six-membered ring of menthol is opened; IC{sub 50} = 0.38 mM). It is suggested that TRPA1 agonists as well as TRPV1 and TRPM8 agonists have an ability to inhibit nerve conduction without TRP activation, although their agonists are quite different in chemical structure from each other.

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

2014-01-01

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.

Effect of tributyltin on adenylate content and enzyme activities of teleost sperm: a biochemical approach to study the mechanisms of toxicant reduced spermatozoa motility.

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Rurangwa, E; Biegniewska, A; Slominska, E; Skorkowski, E F; Ollevier, F

2002-03-01

The effects of tributyltin (TBT) on the energy metabolism and motility of fish spermatozoa were investigated in vitro in African catfish and common carp. A significant (PTBT for 24 h. Exposure of catfish spermatozoa to 2.7-27 microg/l TBT caused an instant decrease in ATP content. In the presence of 27 microg/l TBT approximately 55% of the initial ATP concentration in catfish semen was lost after 60 min incubation while AMP concentrations increased and the total adenine nucleotide (TAN) pool remained unchanged. The reduction in sperm ATP levels could not be attributed to cell death since viability decreased only slightly over the period of exposure. In carp by contrast, none of the adenylates concentrations studied (ATP, ADP and AMP) were affected by TBT exposure at any experimental condition. However, carp sperm motility was significantly reduced by exposure to 2.7 microg/l TBT. Among the enzymes investigated only lactate dehydrogenase (LDH) in catfish sperm was significantly (PTBT treatment with a reduction in activity of approximately 75%. Compared with carp sperm before TBT exposure, that of catfish had lower adenylate contents and overall lower enzymatic activities; this explains its slower sperm velocity and shorter duration of movement as measured by computer assisted sperm analysis (CASA). The present in vitro study shows that catfish spermatozoa are more sensitive to TBT exposure (and probably to other toxicants) than those of carp.

Combined inhibition of monoacylglycerol lipase and cyclooxygenases synergistically reduces neuropathic pain in mice

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Crowe, Molly S; Leishman, Emma; Banks, Matthew L; Gujjar, Ramesh; Mahadevan, Anu; Bradshaw, Heather B; Kinsey, Steven G

2015-01-01

Background and Purpose Neuropathic pain is commonly treated with GABA analogues, steroids or non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDs inhibit one or more COX isozymes but chronic COX inhibition paradoxically increases gastrointestinal inflammation and risk of unwanted cardiovascular events. The cannabinoids also have analgesic and anti-inflammatory properties and reduce neuropathic pain in animal models. The present study investigated the analgesic effects of inhibiting both monoacylglycerol lipase (MAGL) and COX enzymes, using low doses of both inhibitors. Experimental Approach Mice subjected to chronic constriction injury (CCI) were tested for mechanical and cold allodynia after administration of the MAGL inhibitor, JZL184, or the non-selective COX inhibitor diclofenac. Then, both drugs were co-administered at fixed dose proportions of 1:3, 1:1 and 3:1, based on their ED50 values. PGs, endocannabinoids and related lipids were quantified in lumbar spinal cord. Key Results Combining low doses of JZL184 and diclofenac synergistically attenuated mechanical allodynia and additively reduced cold allodynia. The cannabinoid CB1 receptor antagonist, rimonabant, but not the CB2 receptor antagonist, SR144528, blocked the analgesic effects of the JZL184 and diclofenac combination on mechanical allodynia, implying that CB1 receptors were primarily responsible for the anti-allodynia. Diclofenac alone and with JZL184 significantly reduced PGE2 and PGF2α in lumbar spinal cord tissue, whereas JZL184 alone caused significant increases in the endocannabinoid metabolite, N-arachidonoyl glycine. Conclusions and Implications Combining COX and MAGL inhibition is a promising therapeutic approach for reducing neuropathic pain with minimal side effects. PMID:25393148

Antagonistic and Bargaining Games in Optimal Marketing Decisions

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Lipovetsky, S.

2007-01-01

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…

High-Throughput Screening of Small Molecules Identifies Hepcidin Antagonists

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Fung, Eileen; Sugianto, Priscilla; Hsu, Jason; Damoiseaux, Robert; Ganz, Tomas

2013-01-01

Anemia of inflammation (AI) is common in patients with infection, autoimmune diseases, cancer, and chronic kidney disease. Unless the underlying condition can be reversed, treatment options are limited to erythropoiesis-stimulating agents with or without intravenous iron therapy, modalities that are not always effective and can cause serious adverse effects. Hepcidin, the iron regulatory hormone, has been identified as a pathogenic factor in the development of AI. To explore new therapeutic options for AI and other iron-related disorders caused by hepcidin excess, we developed a cell-based screen to identify hepcidin antagonists. Of the 70,000 small molecules in the library, we identified 14 compounds that antagonized the hepcidin effect on ferroportin. One of these was fursultiamine, a Food and Drug Administration (FDA)–approved thiamine derivative. Fursultiamine directly interfered with hepcidin binding to its receptor, ferroportin, by blocking ferroportin C326 thiol residue essential for hepcidin binding. Consequently, fursultiamine prevented hepcidin-induced ferroportin ubiquitination, endocytosis, and degradation in vitro and allowed continuous cellular iron export despite the presence of hepcidin, with IC50 in the submicromolar range. Thiamine, the fursultiamine metabolite, and benfotiamine, another thiamine derivative, did not interfere with the effect of hepcidin on ferroportin. Other FDA-approved thiol-reactive compounds were at least 1000-fold less potent than fursultiamine in antagonizing hepcidin. In vivo, fursultiamine did not reproducibly antagonize the effect of hepcidin on serum iron, likely because of its rapid conversion to inactive metabolites. Fursultiamine is a unique antagonist of hepcidin in vitro that could serve as a template for the development of drug candidates that inhibit the hepcidin-ferroportin interaction. PMID:23292796

A Proof-of-Concept Clinical Trial of A Single Luteal Use of Long-Acting Gonadotropin-Releasing Hormone Antagonist Degarelix in Controlled Ovarian Stimulation for In Vitro Fertilization: Long Antagonist Protocol

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Evangelos G. Papanikolaou

2018-03-01

Full Text Available IntroductionA drawback of gonadotropin-releasing hormone (GnRH antagonist protocols in in vitro fertilization (IVF is that they have limited flexibility in cycle programming. This proof of concept study explored the efficacy of a single-dose, long-acting GnRH antagonist IVF protocol. Trial registration number is NCT03240159, retrospectively registered on March 08, 2017.Materials and methodsThe efficacy of a single-dose long-acting antagonist, degarelix, was explored initially in healthy donors and subsequently in infertile patients. In the first part, five healthy oocyte donors underwent ovarian stimulation with this new protocol: in the late luteal phase, at day 24, a bolus injection of degarelix was administered subcutaneously to control the LH surge in the follicular phase. Ovarian stimulation with gonadotropins was initiated subsequently from day 7 to day 10. End points were first to inhibit the LH surge later in the follicular phase and, second, to retrieve mature oocytes for IVF. In the second part, five infertile women received the same bolus injection of degarelix administered during the luteal phase at day 24. Different gonadotropin starting days (day 2 through day 8 were tested in order to observe possible differences in ovarian stimulation. In these infertile patients, fresh embryo transfers were performed to assess the pregnancy efficacy of this protocol on pregnancy outcomes and to address any possible negative effects on endometrium receptivity.ResultsIn the first part of the study, all donors were effectively downregulated with a single luteal dose of 0.5 ml of degarelix for up to 22 days until the final oocyte maturation triggering day. Mature oocytes were retrieved after 36 h from all patients and all produced 2–7 blastocysts. In the second part, all five infertile patients achieved sufficient LH downregulation and completed ovarian stimulation without any LH surge. All patients (except one with freeze all strategy had

Glycine and GABAA receptors mediate tonic and phasic inhibitory processes that contribute to prepulse inhibition in the goldfish startle network

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Paul C.P. Curtin

2015-03-01

Full Text Available Prepulse inhibition (PPI is understood as an inhibitory process that attenuates sensory flow during early stages (20-1000ms of information processing. Here, we applied in vivo electrophysiology and pharmacology to determine if prepulse inhibition (PPI is mediated by glycine receptors (GlyRs and/or GABAA receptors (GABAARs in the goldfish auditory startle circuit. Specifically, we used selective antagonists to dissect the contributions of target receptors on sound-evoked postsynaptic potentials (PSPs recorded in the neurons that initiate startle, the Mauthner-cells (M-cell. We found that strychnine, a GlyR antagonist, disrupted a fast-activated (5 ms and rapidly (< 50ms decaying (feed-forward inhibitory process that disrupts PPI at 20 ms prepulse/pulse inter-stimulus intervals (ISI. Additionally we observed increases of the evoked postsynaptic potential (PSP peak amplitude (+87.43 ± 21.53%; N=9 and duration (+204 ± 48.91%, N=9. In contrast, treatment with bicuculline, a GABAAR antagonist, caused a general reduction in PPI across all tested ISIs (20-500 ms, essentially eliminating PPI at ISIs from 20-100 ms. Bicuculline also increased PSP peak amplitude (+133.8 ± 10.3%, N=5 and PSP duration (+284.95 ± 65.64%, N=5. Treatment with either antagonist also tonically increased post-synaptic excitability in the M-cells, reflected by an increase in the magnitude of antidromically-evoked action potentials (APs by 15.07 ± 3.21%, N=7 and 16.23 ± 7.08%, N=5 for strychnine and bicuculline, respectively. These results suggest that GABAARs and GlyRs are functionally segregated to short- and longer-lasting sound-evoked (phasic inhibitory processes that contribute to PPI, with the mediation of tonic inhibition by both receptor systems being critical for gain control within the M-cell startle circuit.

Production of non-stimulatory immunoglobulins that inhibit TSH binding in Graves' disease after radioiodine administration

International Nuclear Information System (INIS)

Bech, K.; Bliddal, H.; Siersbaek-Nielsen, K.; Friis, T.

1982-01-01

The effect of single dose of 131 I upon thyroid stimulating immunoglobulins has been studied in twenty-two patients with Graves' disease. The thyroid stimulating immunoglobulins were assessed by parallel measurements of thyrotrophin receptor binding inhibitory immunoglobulins (TBII) and of thyroid adenylate cyclase stimulating immunoglobulins (TACSI) in serum by radioreceptor assay and stimulation of adenylate cyclase respectively. The present study thus confirms that radioiodine therapy is followed by an increase of TBII and TACSI in most patients with Graves' disease. The level of TBII can probably provide a marker for development of hypothyroidism following 131 I therapy and might be involved in its pathogenesis. (author)

Engineering the substrate specificity of the DhbE adenylation domain by yeast cell surface display.

Science.gov (United States)

Zhang, Keya; Nelson, Kathryn M; Bhuripanyo, Karan; Grimes, Kimberly D; Zhao, Bo; Aldrich, Courtney C; Yin, Jun

2013-01-24

The adenylation (A) domains of nonribosomal peptide synthetases (NRPSs) activate aryl acids or amino acids to launch their transfer through the NRPS assembly line for the biosynthesis of many medicinally important natural products. In order to expand the substrate pool of NRPSs, we developed a method based on yeast cell surface display to engineer the substrate specificities of the A-domains. We acquired A-domain mutants of DhbE that have 11- and 6-fold increases in k(cat)/K(m) with nonnative substrates 3-hydroxybenzoic acid and 2-aminobenzoic acid, respectively and corresponding 3- and 33-fold decreases in k(cat)/K(m) values with the native substrate 2,3-dihydroxybenzoic acid, resulting in a dramatic switch in substrate specificity of up to 200-fold. Our study demonstrates that yeast display can be used as a high throughput selection platform to reprogram the "nonribosomal code" of A-domains. Copyright © 2013 Elsevier Ltd. All rights reserved.

PPADS: an antagonist at endothelial P2Y-purinoceptors but not P2U-purinoceptors.

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Brown, C; Tanna, B; Boarder, M R

1995-11-01

1. Bovine aortic endothelial (BAE) cells contain two co-existing receptors for extracellular ATP, the P2Y and P2U-purinoceptors. Here we have determined whether the proposed P2X-purinoceptor antagonist, pyridoxalphosphate-6-azophenyl-2', 4'-disulphonic acid (PPADS) could distinguish between these two receptor subtypes. 2. Cells labelled with myo-[2-3H]-inositol were stimulated with increasing concentrations of either the P2Y-agonist, 2MeSATP, or the P2U-agonist, UTP in the absence or presence of 30 microM PPADS. The accumulation of total [3H]-inositol (poly)phosphates mediated by 2MeSATP was markedly attenuated by PPADS, whereas the response to UTP was not significantly affected. 3. Stimulation of BAE cells with increasing concentrations of ATP showed a reduced response in the presence of 10 microM PPADS, but this effect of the antagonist was not significant. By contrast, inhibition of the response to ADP was profound and highly significant. 4. These observations show that PPADS is not a selective P2X-purinoceptor antagonist, but is able to distinguish between P2Y- and P2YU-purinoceptors in BAE cells, and indicate that this compound may provide a useful tool in the study of multiple subtypes of P2-purinoceptors. Furthermore the results are consistent with the hypothesis that ATP interacts with both receptor subtypes, but that the action of ADP is primarily at the P2Y-purinoceptor in these endothelial cells.

Integrated effect of microbial antagonist, organic amendment and fungicide in controlling seedling mortality (Rhizoctonia solani) and improving yield in pea (Pisum sativum L.).

Science.gov (United States)

Akhter, Wasira; Bhuiyan, Mohamed Khurshed Alam; Sultana, Farjana; Hossain, Mohamed Motaher

2015-01-01

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. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All

Design and synthesis of novel sulfonamide-containing bradykinin hB2 receptor antagonists. 1. Synthesis and SAR of alpha,alpha-dimethylglycine sulfonamides.

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Fattori, Daniela; Rossi, Cristina; Fincham, Christopher I; Berettoni, Marco; Calvani, Federico; Catrambone, Fernando; Felicetti, Patrizia; Gensini, Martina; Terracciano, Rosa; Altamura, Maria; Bressan, Alessandro; Giuliani, Sandro; Maggi, Carlo A; Meini, Stefania; Valenti, Claudio; Quartara, Laura

2006-06-15

We recently published the extensive in vivo pharmacological characterization of MEN 16132 (J. Pharmacol. Exp. Ther. 2005, 616-623; Eur. J. Pharmacol. 2005, 528, 7), a member of the sulfonamide-containing human B(2) receptor (hB(2)R) antagonists. Here we report, in detail, how this family of compounds was designed, synthesized, and optimized to provide a group of products with subnanomolar affinity for the hB(2)R and high in vivo potency after topical administration to the respiratory tract. The series was designed on the basis of indications from the X-ray structures of the key structural motifs A and B present in known antagonists and is characterized by the presence of an alpha,alpha-dialkyl amino acid. The first lead (17) of the series was submitted to extensive chemical work to elucidate the structural requirements to increase hB(2) receptor affinity and antagonist potency in bioassays expressing the human B(2) receptor (hB(2)R). The following structural features were selected: a 2,4-dimethylquinoline moiety and a piperazine linker acylated with a basic amino acid. The representative lead compound 68 inhibited the specific binding of [(3)H]BK to hB(2)R with a pKi of 9.4 and antagonized the BK-induced inositolphosphate (IP) accumulation in recombinant cell systems expressing the hB(2)R with a pA(2) of 9.1. Moreover, compound 68 when administered (300 nmol/kg) intratracheally in the anesthetized guinea pig, was able to significantly inhibit BK-induced bronchoconstriction for up to 120 min after its administration, while having a lower and shorter lasting effect on hypotension.

Pharmacological analysis of calcium antagonist receptors

International Nuclear Information System (INIS)

Reynolds, I.J.

1987-01-01

This work focuses on two aspects of the action of calcium antagonist drugs, namely, the interaction of drugs with receptors for verapamil-like calcium antagonists, and the interactions of drugs with voltage-sensitive calcium fluxes in rat brain synaptosomes. From binding studies I have found that the ligand of choice for labeling the verapamil receptor is (-)[ 3 H]desmethoxy-verapamil. This drug labels potently, reversibly and stereoselectively two receptors in membranes prepared from rat brain and rabbit skeletal muscle tissues. In equilibrium studies dihydropyridine calcium antagonists interact in a non-competitive fashion, while many non-DHPs are apparently competitive. In-depth kinetic studies in skeletal muscle membranes indicate that the two receptors are linked in a negative heterotropic fashion, and that low-affinity binding of (-) [ 3 H]desmethoxy-verapamil may be to the diltiazem receptor. However, these studies were not able to distinguish between the hypothesis that diltiazem binds to spatially separate, allosterically coupled receptors, and the hypothesis that diltiazem binds to a subsite of the verapamil receptor

HIV-1 entry inhibition by small-molecule CCR5 antagonists: A combined molecular modeling and mutant study using a high-throughput assay

International Nuclear Information System (INIS)

Labrecque, Jean; Metz, Markus; Lau, Gloria; Darkes, Marilyn C.; Wong, Rebecca S.Y.; Bogucki, David; Carpenter, Bryon; Chen Gang; Li Tongshuang; Nan, Susan; Schols, Dominique; Bridger, Gary J.; Fricker, Simon P.; Skerlj, Renato T.

2011-01-01

Based on the attrition rate of CCR5 small molecule antagonists in the clinic the discovery and development of next generation antagonists with an improved pharmacology and safety profile is necessary. Herein, we describe a combined molecular modeling, CCR5-mediated cell fusion, and receptor site-directed mutagenesis approach to study the molecular interactions of six structurally diverse compounds (aplaviroc, maraviroc, vicriviroc, TAK-779, SCH-C and a benzyloxycarbonyl-aminopiperidin-1-yl-butane derivative) with CCR5, a coreceptor for CCR5-tropic HIV-1 strains. This is the first study using an antifusogenic assay, a model of the interaction of the gp120 envelope protein with CCR5. This assay avoids the use of radioactivity and HIV infection assays, and can be used in a high throughput mode. The assay was validated by comparison with other established CCR5 assays. Given the hydrophobic nature of the binding pocket several binding models are suggested which could prove useful in the rational drug design of new lead compounds.

Characterization and design of antagonistic shape memory alloy actuators

International Nuclear Information System (INIS)

Georges, T; Brailovski, V; Terriault, P

2012-01-01

Antagonistic shape memory actuators use opposing shape memory alloy (SMA) elements to create devices capable of producing differential motion paths and two-way mechanical work in a very efficient manner. There is no requirement for additional bias elements to ‘re-arm’ the actuators and allow repetitive actuation. The work generation potential of antagonistic shape memory actuators is determined by specific SMA element characteristics and their assembly conditions. In this study, the selected SMA wires are assembled in antagonistic configuration and characterized using a dedicated test bench to evaluate their stress–strain characteristics as a function of the number of cycles. Using these functional characteristics, a so-called ‘working envelope’ is built to assist in the design of such an actuator. Finally, the test bench is used to simulate a real application of an antagonistic actuator (case study). (paper)

Vorapaxar: The Current Role and Future Directions of a Novel Protease-Activated Receptor Antagonist for Risk Reduction in Atherosclerotic Disease.

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Gryka, Rebecca J; Buckley, Leo F; Anderson, Sarah M

2017-03-01

Despite the current standard of care, patients with cardiovascular disease remain at a high risk for recurrent events. Inhibition of thrombin-mediated platelet activation through protease-activated receptor-1 antagonism may provide reductions in atherosclerotic disease beyond those achievable with the current standard of care. Our primary objective is to evaluate the clinical literature regarding the role of vorapaxar (Zontivity™) in the reduction of cardiovascular events in patients with a history of myocardial infarction and peripheral artery disease. In particular, we focus on the potential future directions for protease-activating receptor antagonists in the treatment of a broad range of atherosclerotic diseases. A literature search of PubMed and EBSCO was conducted to identify randomized clinical trials from August 2005 to June 2016 using the search terms: 'vorapaxar', 'SCH 530348', 'protease-activated receptor-1 antagonist', and 'Zontivity™'. Bibliographies were searched and additional resources were obtained. Vorapaxar is a first-in-class, protease-activated receptor-1 antagonist. The Thrombin Receptor Antagonist for Clinical Event Reduction (TRACER) trial did not demonstrate a significant reduction in a broad primary composite endpoint. However, the Thrombin-Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events (TRA 2°P-TIMI 50) trial examined a more traditional composite endpoint and found a significant benefit with vorapaxar. Vorapaxar significantly increased bleeding compared with standard care. Ongoing trials will help define the role of vorapaxar in patients with peripheral arterial disease, patients with diabetes mellitus, and other important subgroups. The use of multivariate modeling may enable the identification of subgroups with maximal benefit and minimal harm from vorapaxar. Vorapaxar provides clinicians with a novel mechanism of action to further reduce the burden of ischemic heart disease. Identification of

Cultivable bacteria populations associated with leaves of banana and plantain plants and their antagonistic activity against Mycosphaerella fijiensis.

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Ceballos, Isabel; Mosquera, Sandra; Angulo, Mónica; Mira, John J; Argel, Luz Edith; Uribe-Velez, Daniel; Romero-Tabarez, Magally; Orduz-Peralta, Sergio; Villegas, Valeska

2012-10-01

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.

Dopamine antagonists and brief vision distinguish lens-induced- and form-deprivation-induced myopia.

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Nickla, Debora L; Totonelly, Kristen

2011-11-01

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 effects of brief periods of unrestricted vision differ for form-deprivation versus negative lens-wear, which may imply different growth

FMRFamide: low affinity inhibition of opioid binding to rabbit brain membranes

International Nuclear Information System (INIS)

Zhu, X.Z.; Raffa, R.B.

1986-01-01

FMRFamide (Phe-Met-Arg-Phe-NH 2 ) was first isolated from the ganglia of molluscs by Price and Greenberg in 1977. The peptide was subsequently shown to have diverse actions on various types of molluscan and mammalian tissues. The presence of immunoreactive FMRFamide-like material (irFMRF) in multiple areas of rat brain, spinal cord, and gastrointestinal tract suggests that irFMRF may have a physiological role in mammals. Tang, Yang and Costa recently demonstrated that FMRFamide attenuates morphine antinociception in rats and postulated, based on this and several other lines of evidence, that irFMRF might be an endogenous opioid antagonist. In the present study, they tested the ability of FMRFamide to inhibit the binding of opioid receptor ligands to rabbit membrane preparations. FMRFamide inhibited the specific binding of both 3 [H]-dihydromorphine and 3 [H]-ethylketocyclazocine (IC 50 = 14 μM and 320 μM, respectively) in a dose-related manner, suggesting that FMRFamide may affect binding to at least two types of opioid receptors (mu and kappa). These data are consistent with the concept that irFMRF might act as an endogenous opioid antagonist. However, the low affinity of FMRFamide leaves open the possibility of another mechanism of opioid antagonism, such as neuromodulation

FMRFamide: low affinity inhibition of opioid binding to rabbit brain membranes

Energy Technology Data Exchange (ETDEWEB)

Zhu, X.Z.; Raffa, R.B.

1986-03-05

FMRFamide (Phe-Met-Arg-Phe-NH/sub 2/) was first isolated from the ganglia of molluscs by Price and Greenberg in 1977. The peptide was subsequently shown to have diverse actions on various types of molluscan and mammalian tissues. The presence of immunoreactive FMRFamide-like material (irFMRF) in multiple areas of rat brain, spinal cord, and gastrointestinal tract suggests that irFMRF may have a physiological role in mammals. Tang, Yang and Costa recently demonstrated that FMRFamide attenuates morphine antinociception in rats and postulated, based on this and several other lines of evidence, that irFMRF might be an endogenous opioid antagonist. In the present study, they tested the ability of FMRFamide to inhibit the binding of opioid receptor ligands to rabbit membrane preparations. FMRFamide inhibited the specific binding of both /sup 3/(H)-dihydromorphine and /sup 3/(H)-ethylketocyclazocine (IC/sub 50/ = 14 ..mu..M and 320 ..mu..M, respectively) in a dose-related manner, suggesting that FMRFamide may affect binding to at least two types of opioid receptors (mu and kappa). These data are consistent with the concept that irFMRF might act as an endogenous opioid antagonist. However, the low affinity of FMRFamide leaves open the possibility of another mechanism of opioid antagonism, such as neuromodulation.