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Sample records for adenosine

  1. Adenosine in exercise adaptation.

    Simpson, R E; Phillis, J. W.

    1992-01-01

    By influencing the regulation of the mechanisms of angiogenesis, erythropoietin production, blood flow, myocardial glucose uptake, glycogenolysis, systolic blood pressure, respiration, plasma norepinephrine and epinephrine levels, adenosine may exert a significant effect on the body's adaptation response to exercise. However, adenosine's possible influence over the vasodilatory response to exercise in skeletal muscle is controversial and more research is required to resolve this issue. Variou...

  2. Adenosine Receptors and Asthma

    Wilson, Constance N; Nadeem, Ahmed; Spina, Domenico; Brown, Rachel; Page, Clive P.; Jamal Mustafa, S.

    2009-01-01

    The pathophysiological processes underlying respiratory diseases like asthma are complex, resulting in an overwhelming choice of potential targets for the novel treatment of this disease. Despite this complexity, asthmatic subjects are uniquely sensitive to a range of substances like adenosine, thought to act indirectly to evoke changes in respiratory mechanics and in the underlying pathology, and thereby to offer novel insights into the pathophysiology of this disease. Adenosine is of partic...

  3. Adenosine and sleep

    Behavioral and biochemical approaches have been used to determine the relative contribution of endogenous adenosine and adenosine receptors to the sleep-wake cycle in the rat. Adenosine concentrations in specific areas of the rat brain were not affected by 24 hours of total sleep deprivation, or by 24 or 48 hours of REM sleep deprivation. In order to assess the effect of REM sleep deprivation on adenosine A1 receptors, 3H-L-PIA binding was measured. The Bmax values for 3H-L-PIA binding to membrane preparations of the cortices and corpus striata from 48 hour REM sleep-deprived animals were increased 14.8% and 23%, respectively. These increases were not maintained following the cessation of sleep deprivation and recovered within 2 hours. The results of a 96 hour REM deprivation experiment were similar to those of the 48 hour REM sleep deprivation experiment. However, these increases were not evident in similar structures taken from stress control animals, and conclusively demonstrated that the changes in 3H-L-PIA binding resulted from REM sleep deprivation and not from stress

  4. Adenosine and sleep

    Yanik, G.M. Jr.

    1987-01-01

    Behavioral and biochemical approaches have been used to determine the relative contribution of endogenous adenosine and adenosine receptors to the sleep-wake cycle in the rat. Adenosine concentrations in specific areas of the rat brain were not affected by 24 hours of total sleep deprivation, or by 24 or 48 hours of REM sleep deprivation. In order to assess the effect of REM sleep deprivation on adenosine A/sub 1/ receptors, /sup 3/H-L-PIA binding was measured. The Bmax values for /sup 3/H-L-PIA binding to membrane preparations of the cortices and corpus striata from 48 hour REM sleep-deprived animals were increased 14.8% and 23%, respectively. These increases were not maintained following the cessation of sleep deprivation and recovered within 2 hours. The results of a 96 hour REM deprivation experiment were similar to those of the 48 hour REM sleep deprivation experiment. However, these increases were not evident in similar structures taken from stress control animals, and conclusively demonstrated that the changes in /sup 3/H-L-PIA binding resulted from REM sleep deprivation and not from stress.

  5. Adenosine and Sleep

    Bjorness, Theresa E.; Greene, Robert W.

    2009-01-01

    Over the last several decades the idea that adenosine (Ado) plays a role in sleep control was postulated due in large part to pharmacological studies that showed the ability of Ado agonists to induce sleep and Ado antagonists to decrease sleep. A second wave of research involving in vitro cellular analytic approaches and subsequently, the use of neurochemical tools such as microdialysis, identified a population of cells within the brainstem and basal forebrain arousal centers, with activity t...

  6. Adenosine-Associated Delivery Systems

    Kazemzadeh-Narbat, Mehdi; Annabi, Nasim; Tamayol, Ali; Oklu, Rahmi; Ghanem, Amyl; Khademhosseini, Ali

    2016-01-01

    Adenosine is a naturally occurring purine nucleoside in every cell. Many critical treatments such as modulating irregular heartbeat (arrhythmias), regulation of central nervous system (CNS) activity, and inhibiting seizural episodes can be carried out using adenosine. Despite the significant potential therapeutic impact of adenosine and its derivatives, the severe side effects caused by their systemic administration have significantly limited their clinical use. In addition, due to adenosine’s extremely short half-life in human blood (less than 10 s), there is an unmet need for sustained delivery systems to enhance efficacy and reduce side effects. In this paper, various adenosine delivery techniques, including encapsulation into biodegradable polymers, cell-based delivery, implantable biomaterials, and mechanical-based delivery systems, are critically reviewed and the existing challenges are highlighted. PMID:26453156

  7. Adenosine-induced activation of esophageal nociceptors.

    Ru, F; Surdenikova, L; Brozmanova, M; Kollarik, M

    2011-03-01

    Clinical studies implicate adenosine acting on esophageal nociceptive pathways in the pathogenesis of noncardiac chest pain originating from the esophagus. However, the effect of adenosine on esophageal afferent nerve subtypes is incompletely understood. We addressed the hypothesis that adenosine selectively activates esophageal nociceptors. Whole cell perforated patch-clamp recordings and single-cell RT-PCR analysis were performed on the primary afferent neurons retrogradely labeled from the esophagus in the guinea pig. Extracellular recordings were made from the isolated innervated esophagus. In patch-clamp studies, adenosine evoked activation (inward current) in a majority of putative nociceptive (capsaicin-sensitive) vagal nodose, vagal jugular, and spinal dorsal root ganglia (DRG) neurons innervating the esophagus. Single-cell RT-PCR analysis indicated that the majority of the putative nociceptive (transient receptor potential V1-positive) neurons innervating the esophagus express the adenosine receptors. The neural crest-derived (spinal DRG and vagal jugular) esophageal nociceptors expressed predominantly the adenosine A(1) receptor while the placodes-derived vagal nodose nociceptors expressed the adenosine A(1) and/or A(2A) receptors. Consistent with the studies in the cell bodies, adenosine evoked activation (overt action potential discharge) in esophageal nociceptive nerve terminals. Furthermore, the neural crest-derived jugular nociceptors were activated by the selective A(1) receptor agonist CCPA, and the placodes-derived nodose nociceptors were activated by CCPA and/or the selective adenosine A(2A) receptor CGS-21680. In contrast to esophageal nociceptors, adenosine failed to stimulate the vagal esophageal low-threshold (tension) mechanosensors. We conclude that adenosine selectively activates esophageal nociceptors. Our data indicate that the esophageal neural crest-derived nociceptors can be activated via the adenosine A(1) receptor while the placodes

  8. Adenosine in inflammatory joint diseases

    Chan, E. S. L.; Fernandez, P.; Cronstein, B. N.

    2007-01-01

    Inflammatory joint diseases are a group of heterogeneous disorders with a variety of different etiologies and disease manifestations. However, there are features that are common to all of them: first, the recruitment of various inflammatory cell types that are attracted to involved tissues over the course of the disease process. Second, the treatments used in many of these diseases are commonly medications that suppress or alter immune function. The demonstration that adenosine has endogenous...

  9. Role of extracellular adenosine in Drosophila

    FENCKOVÁ, Michaela

    2011-01-01

    This thesis describes several aspects of the role for extracellular adenosine in Drosophila. Reverse genetic, molecular and microscopic methods together with the most forefront Drosophila research techniques have been applied to elucidate the role of adenosine signaling in the regulation of development, physiology and metabolism of Drosophila larvae. The thesis helps to establish the model for extracellular adenosine as a stress-signal for the release of energy stores. It also describes the e...

  10. Effect of adenosine and adenosine analogs on [14C]aminopyrine accumulation by rabbit parietal cells

    Adenosine receptors that modulate adenylate cyclase activity have been identified recently in a number of tissues. Adenosine A2 receptor is stimulatory to adenylate cyclase, whereas adenosine A1 receptor is inhibitory to adenylate cyclase. We investigated the effect of adenosine and its analogs on [14C]aminopyrine accumulation by rabbit parietal cells. Rabbit gastric mucosal cells were isolated by enzyme digestion. Parietal cells were enriched by nonlinear percoll gradients. [14C]Aminopyrine accumulation was used as an indicator of acid secretion. The effect of 2-chloroadenosine on histamine-stimulated [14C]aminopyrine accumulation was studied. The effects of N-ethylcarboxamideadenosine, 2-chloroadenosine, stable analogs of adenosine, and adenosine on [14C]aminopyrine accumulation were assessed. Cyclic AMP content of parietal cells was determined by radioimmunoassay. Histamine and carbachol, known secretagogues, stimulated [14C]aminopyrine accumulation. 2-Chloroadenosine did not suppress histamine-stimulated [14C]aminopyrine accumulation. 2-Chloroadenosine, N-ethylcarboxamideadenosine, and adenosine dose dependently increased [14C]aminopyrine accumulation. The order of potency was N-ethylcarboxamideadenosine greater than 2-chloroadenosine greater than adenosine. 8-Phenyltheophylline and theophylline, adenosine-receptor antagonists, or cimetidine did not have significant effects on the increase of AP uptake induced by 2-chloroadenosine. Coadministration of dipyridamole, and adenosine uptake inhibitor, augmented the effect of adenosine on [14C]aminopyrine accumulation. 2-Chloroadenosine, N-ethylcarboxamideadenosine, and adenosine each induced a significant increase in cellular cyclic AMP. We conclude that there may be adenosine A2 receptors on rabbit parietal cells which modulate gastric acid secretion

  11. Optical Aptasensors for Adenosine Triphosphate

    Ng, Stella; Lim, Hui Si; Ma, Qian; Gao, Zhiqiang

    2016-01-01

    Nucleic acids are among the most researched and applied biomolecules. Their diverse two- and three-dimensional structures in conjunction with their robust chemistry and ease of manipulation provide a rare opportunity for sensor applications. Moreover, their high biocompatibility has seen them being used in the construction of in vivo assays. Various nucleic acid-based devices have been extensively studied as either the principal element in discrete molecule-like sensors or as the main component in the fabrication of sensing devices. The use of aptamers in sensors - aptasensors, in particular, has led to improvements in sensitivity, selectivity, and multiplexing capacity for a wide verity of analytes like proteins, nucleic acids, as well as small biomolecules such as glucose and adenosine triphosphate (ATP). This article reviews the progress in the use of aptamers as the principal component in sensors for optical detection of ATP with an emphasis on sensing mechanism, performance, and applications with some discussion on challenges and perspectives. PMID:27446501

  12. Adenosine regulation of alveolar fluid clearance

    Factor, Phillip; Mutlu, Göskhan M.; Chen, Lan; Mohameed, Jameel; Akhmedov, Alexander T.; Meng, Fan Jing; Jilling, Tamas; Lewis, Erin Rachel; Johnson, Meshell D.; Xu, Anna; Kass, Daniel; Martino, Janice M.; Bellmeyer, Amy; Albazi, John S.; Emala, Charles

    2007-01-01

    Adenosine is a purine nucleoside that regulates cell function through G protein-coupled receptors that activate or inhibit adenylyl cyclase. Based on the understanding that cAMP regulates alveolar epithelial active Na+ transport, we hypothesized that adenosine and its receptors have the potential to regulate alveolar ion transport and airspace fluid content. Herein, we report that type 1 (A1R), 2a (A2aR), 2b (A2bR), and 3 (A3R) adenosine receptors are present in rat and mouse lungs and alveol...

  13. Adenosine triphosphate inhibition of yeast trehalase.

    Panek, A D

    1969-09-01

    Yeast trehalase has been found to be inhibited non-competitively by adenosine triphosphate. Such a biological control could explain the accumulation of trehalose during the stationary phase of the growth curve. PMID:5370287

  14. Role of adenosine receptors in caffeine tolerance

    Caffeine is a competitive antagonist at adenosine receptors. Receptor up-regulation during chronic drug treatment has been proposed to be the mechanism of tolerance to the behavioral stimulant effects of caffeine. This study reassessed the role of adenosine receptors in caffeine tolerance. Separate groups of rats were given scheduled access to drinking bottles containing plain tap water or a 0.1% solution of caffeine. Daily drug intake averaged 60-75 mg/kg and resulted in complete tolerance to caffeine-induced stimulation of locomotor activity, which could not be surmounted by increasing the dose of caffeine. 5'-N-ethylcarboxamidoadenosine (0.001-1.0 mg/kg) dose dependently decreased the locomotor activity of caffeine-tolerant rats and their water-treated controls but was 8-fold more potent in the latter group. Caffeine (1.0-10 mg/kg) injected concurrently with 5-N-ethylcarboxamidoadenosine antagonized the decreases in locomotor activity comparably in both groups. Apparent pA2 values for tolerant and control rats also were comparable: 5.05 and 5.11. Thus, the adenosine-antagonist activity of caffeine was undiminished in tolerant rats. The effects of chronic caffeine administration on parameters of adenosine receptor binding and function were measured in cerebral cortex. There were no differences between brain tissue from control and caffeine-treated rats in number and affinity of adenosine binding sites or in receptor-mediated increases (A2 adenosine receptor) and decreases (A1 adenosine receptor) in cAMP accumulation. These results are consistent with theoretical arguments that changes in receptor density should not affect the potency of a competitive antagonist. Experimental evidence and theoretical considerations indicate that up-regulation of adenosine receptors is not the mechanism of tolerance to caffeine-induced stimulation of locomotor activity

  15. Electrocardiographic profile of adenosine pharmacological stress testing

    Sun, Hao; TIAN, YUEQIN; ZHENG, LIHUI; Pan, Qingrong; XIE, BOQIA

    2015-01-01

    Adenosine stress testing in conjunction with radionuclide myocardial perfusion imaging has become a common approach for the detection of coronary artery diseases in patients who are unable to perform adequate levels of exercise. However, specific electrocardiographic alterations during the test have been rarely described. Using a Chinese population, the aim of the present study was to provide a detailed electrocardiographic profile of adenosine stress testing. The study population included 1,...

  16. Adenosine stress protocols for myocardial perfusion imaging

    Baškot Branislav

    2008-01-01

    Full Text Available Background/Aim. Treadmill test combined with myocardial perfusion scintigraphy (MPS is a commonly used technique in the assessment of coronary artery disease. There are many patients, however, who may not be able to undergo treadmill test. Such patients would benefit from pharmacological stress procedures combined with MPS. The most commonly used pharmacological agents for cardiac stress are coronary vasodilatators (adenosine, dipyridamol and catecholamines. Concomitant low-level treadmill exercise with adenosine pharmacologic stress (AdenoEX during MPS has become commonly used in recent years. A number of studies have demonstrated a beneficial impact of AdenoEX protocol. The aim of the study was, besides introducing into practice the two types of protocols of pharmatological stress test with adenosine, as a preparation for MPS, to compare and monitor the frequency of their side effects to quality, acquisition, as well as to standardize the onset time of acquisition (diagnostic imaging for both protocols. Methods. A total of 130 patients underwent pharmacological stress test with adenosine (vasodilatator. In 108 of the patients we performed concomitant exercise (AdenoEX of low level (50W by a bicycle ergometar. In 28 of the patients we performed Adenosine abbreviated protocol (AdenoSCAN. Side effects of adenosine were followed and compared between the two kinds of protocols AdenoEX and AdenoSCAN. Also compared were image quality and suggested time of acquisition after the stress test. Results. Numerous side effects were found, but being short-lived they did not require any active interventions. The benefit of AdenoEX versus AdenoSCAN included decreased side effects (62% vs 87%, improved safety and patients tolerance, improved target-to-background ratios because of less subdiaphragmatic activity, earlier acquisition, and improved sensitivity. Conclusion. The safety and efficacy of adenosine pharmacological stress is even better with concomitant

  17. Internalization and desensitization of adenosine receptors

    Klaasse, Elisabeth C.; IJzerman, Adriaan P.; de Grip, Willem J.; Beukers, Margot W.

    2007-01-01

    Until now, more than 800 distinct G protein-coupled receptors (GPCRs) have been identified in the human genome. The four subtypes of the adenosine receptor (A1, A2A, A2B and A3 receptor) belong to this large family of GPCRs that represent the most widely targeted pharmacological protein class. Since adenosine receptors are widespread throughout the body and involved in a variety of physiological processes and diseases, there is great interest in understanding how the different subtypes are re...

  18. 21 CFR 864.7040 - Adenosine triphosphate release assay.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Adenosine triphosphate release assay. 864.7040 Section 864.7040 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Adenosine triphosphate release assay. (a) Identification. An adenosine triphosphate release assay is...

  19. Study of Ectonucleotidases and Adenosine Deaminases in Drosophila

    PREUER, Kristina

    2013-01-01

    Extracellular adenosine triphosphate and extracellular adenosine are important regulatory molecules in the human immune system. The concentrations of these molecules are in turn regulated by ectonucleotidases and adenosine deaminases. In this thesis I attempt to test the gene silencing efficiency of RNA interference for three different genes coding for such enzymes in the model organism Drosophila melanogaster.

  20. Internalization and desensitization of adenosine receptors.

    Klaasse, E.C.; IJzerman, A.P.; Grip, W.J. de; Beukers, M.W.

    2008-01-01

    Until now, more than 800 distinct G protein-coupled receptors (GPCRs) have been identified in the human genome. The four subtypes of the adenosine receptor (A(1), A(2A), A(2B) and A(3) receptor) belong to this large family of GPCRs that represent the most widely targeted pharmacological protein clas

  1. Effects of adenosine infusion into renal interstitium on renal hemodynamics

    This study was designed to investigate the hemodynamic effects of exogenous adenosine in the interstitium of the rat kidney. Adenosine or its analogues were infused into the renal interstitium by means of chronically implanted capsules. In fusion of adenosine decreased glomerular filtration rate (GFR) from 0.81 +/- 0.06 to 0.37 +/- 0.06 ml/min while having no effect on renal blood flow (RBF). The metabolically stable analogue, 2-chloradenosine (2-ClAdo), decreased GFR from 0.73 +/- 0.07 to 021 +/- 0.06 ml/min. Interstitial infusion of theophylline, an adenosine receptor antagonist, completely abolished the effects of adenosine and 2-ClAdo on GFR. The distribution of adenosine, when infused into the renal interstitium, was determined using radiolabeled 5'-(N-ethyl)-carboxamidoadenosine (NECA), a metabolically stable adenosine agonist. After continuous infusion, [3H]NECA was distributed throughout the kidney. The effects of NECA to reduce GFR were similar to those of adenosine and 2-ClAdo. They conclude that increased levels of adenosine in the renal interstitium markedly decrease GFR without affecting RBF in steady-state conditions. The marked effects of adenosine agonists during their infusion into the renal interstitium and the complete blockade of these effects by theophylline suggest an extracellular action of adenosine

  2. Adenosine: An immune modulator of inflammatory bowel diseases

    Jeff Huaqing Ye; Vazhaikkurichi M Rajendran

    2009-01-01

    Inflammatory bowel disease (IBD) is a common and lifelong disabling gastrointestinal disease. Emerging treatments are being developed to target inflammatory cytokines which initiate and perpetuate the immune response. Adenosine is an important modulator of inflammation and its anti-inflammatory effects have been well established in humans as well as in animal models. High extracellular adenosine suppresses and resolves chronic inflammation in IBD models. High extracellular adenosine levels could be achieved by enhanced adenosine absorption and increased de novo synthesis. Increased adenosine concentration leads to activation of the A2a receptor on the cell surface of immune and epithelial cells that would be a potential therapeutic target for chronic intestinal inflammation. Adenosine is transported via concentrative nucleoside transporter and equilibrative nucleoside transporter transporters that are localized in apical and basolateral membranes of intestinal epithelial cells, respectively. Increased extracellular adenosine levels activate the A2a receptor, which would reduce cytokines responsible for chronic inflammation.

  3. Adenosine receptors and asthma in humans

    Wilson, C N

    2008-01-01

    According to an executive summary of the GINA dissemination committee report, it is now estimated that approximately 300 million people (5% of the global population or 1 in 20 persons) have asthma. Despite the scientific progress made over the past several decades toward improving our understanding of the pathophysiology of asthma, there is still a great need for improved therapies, particularly oral therapies that enhance patient compliance and that target new mechanisms of action. Adenosine...

  4. Aminopyrimidine derivatives as adenosine antagonists / Janke Kleynhans

    Kleynhans, Janke

    2013-01-01

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

  5. Role of adenosine in oligodendrocyte precursor maturation

    Elisabetta Coppi

    2015-04-01

    Full Text Available Differentiation and maturation of oligodendroglial cells are postnatal processes involving specific morphological changes correlated with the expression of stage-specific surface antigens and functional voltage-gated ion channels. A small fraction of oligodendrocyte progenitor cells (OPCs generated during development are maintained in an immature and slowly proliferative or quiescent state in the adult central nervous system (CNS representing an endogenous reservoir of immature cells. Adenosine receptors are expressed by OPCs and a key role of adenosine in oligodendrocyte maturation has been recently recognised. As evaluated on OPC cultures, adenosine by stimulating A1 receptors, promotes oligodendrocyte maturation and inhibits their proliferation; on the contrary by stimulating A2A receptors, it inhibits oligodendrocyte maturation. A1 and A2A receptor-mediated effects are related to opposite modifications of outward delayed rectifying membrane K+ currents (IK that are involved in regulation of oligodendrocyte differentiation. Brain A1 and A2A receptors might represent new molecular targets for drugs useful in demyelinating pathologies, such as multiple sclerosis (MS, stroke and brain trauma.

  6. Effect of adenosine and adenosine analogs on ( sup 14 C)aminopyrine accumulation by rabbit parietal cells

    Ota, S.; Hiraishi, H.; Terano, A.; Mutoh, H.; Kurachi, Y.; Shimada, T.; Ivey, K.J.; Sugimoto, T. (Univ. of Tokyo (Japan))

    1989-12-01

    Adenosine receptors that modulate adenylate cyclase activity have been identified recently in a number of tissues. Adenosine A2 receptor is stimulatory to adenylate cyclase, whereas adenosine A1 receptor is inhibitory to adenylate cyclase. We investigated the effect of adenosine and its analogs on (14C)aminopyrine accumulation by rabbit parietal cells. Rabbit gastric mucosal cells were isolated by enzyme digestion. Parietal cells were enriched by nonlinear percoll gradients. (14C)Aminopyrine accumulation was used as an indicator of acid secretion. The effect of 2-chloroadenosine on histamine-stimulated (14C)aminopyrine accumulation was studied. The effects of N-ethylcarboxamideadenosine, 2-chloroadenosine, stable analogs of adenosine, and adenosine on (14C)aminopyrine accumulation were assessed. Cyclic AMP content of parietal cells was determined by radioimmunoassay. Histamine and carbachol, known secretagogues, stimulated (14C)aminopyrine accumulation. 2-Chloroadenosine did not suppress histamine-stimulated (14C)aminopyrine accumulation. 2-Chloroadenosine, N-ethylcarboxamideadenosine, and adenosine dose dependently increased (14C)aminopyrine accumulation. The order of potency was N-ethylcarboxamideadenosine greater than 2-chloroadenosine greater than adenosine. 8-Phenyltheophylline and theophylline, adenosine-receptor antagonists, or cimetidine did not have significant effects on the increase of AP uptake induced by 2-chloroadenosine. Coadministration of dipyridamole, and adenosine uptake inhibitor, augmented the effect of adenosine on (14C)aminopyrine accumulation. 2-Chloroadenosine, N-ethylcarboxamideadenosine, and adenosine each induced a significant increase in cellular cyclic AMP. We conclude that there may be adenosine A2 receptors on rabbit parietal cells which modulate gastric acid secretion.

  7. Turnover of adenosine in plasma of human and dog blood

    To determine half-life and turnover of plasma adenosine, heparinized blood from healthy volunteers was incubated with radiolabeled adenosine in the physiological concentration range of 0.1-1 microM. Plasma levels of adenosine in vitro were 82 +/- 14 nM and were similar to those determined immediately after blood collection with a ''stopping solution.'' Dipyridamole (83 microM) and erythro-9(2-hydroxynon-3yl)-adenine (EHNA) (8 microM) did not measurably alter basal adenosine levels but completely blocked the uptake of added adenosine. Inhibition of ecto-5'-nucleotidase with 100 microM alpha, beta-methyleneadenosine 5'-diphosphate (AOPCP) reduced plasma adenosine to 22 +/- 6 nM. For the determination of adenosine turnover, the decrease in specific radioactivity of added [3H]adenosine was measured using a dipyridamole-containing stopping solution. Without altering basal adenosine levels, the half-life was estimated to be 0.6 s. Similar experiments were carried out with washed erythrocytes or in the presence of AOPCP, yielding half-lives of 0.7 and 0.9 s, respectively. When the initial adenosine concentration was 1 microM, its specific activity decreased by only 11% within 5 s, whereas total plasma adenosine exponentially decreased with a half-life of 1.5 s. Venous plasma concentrations were measured after relief of a 3-min forearm ischemia. Changes in plasma adenosine did not correlate well with changes in blood flow but were augmented in the presence of dipyridamole

  8. Silk Fibroin Encapsulated Powder Reservoirs for Sustained Release of Adenosine

    Pritchard, Eleanor M.; Szybala, Cory; Boison, Detlev; Kaplan, David L.

    2010-01-01

    Due to its unique properties, silk fibroin was studied as a biodegradable polymer vehicle for sustained, local delivery of the anticonvulsant adenosine from encapsulated reservoirs. Silk is a biologically derived protein polymer that is biocompatible, mechanically strong and degrades to non-toxic products in vivo. To achieve local, sustained, controlled adenosine release from fully degradable implants, solid adenosine powder reservoirs were coated with silk fibroin. Material properties of the...

  9. A Metabolic Immune Checkpoint: Adenosine in Tumor Microenvironment

    Ohta, Akio

    2016-01-01

    Within tumors, some areas are less oxygenated than others. Since their home ground is under chronic hypoxia, tumor cells adapt to this condition by activating aerobic glycolysis; however, this hypoxic environment is very harsh for incoming immune cells. Deprivation of oxygen limits availability of energy sources and induces accumulation of extracellular adenosine in tumors. Extracellular adenosine, upon binding with adenosine receptors on the surface of various immune cells, suppresses pro-inflammatory activities. In addition, signaling through adenosine receptors upregulates a number of anti-inflammatory molecules and immunoregulatory cells, leading to the establishment of a long-lasting immunosuppressive environment. Thus, due to hypoxia and adenosine, tumors can discourage antitumor immune responses no matter how the response was induced, whether it was spontaneous or artificially introduced with a therapeutic intention. Preclinical studies have shown the significance of adenosine in tumor survival strategy by demonstrating tumor regression after inactivation of adenosine receptors, inhibition of adenosine-producing enzymes, or reversal of tissue hypoxia. These promising results indicate a potential use of the inhibitors of the hypoxia–adenosine pathway for cancer immunotherapy. PMID:27066002

  10. Adenosine A1 receptor agonists inhibit trigeminovascular nociceptive transmission

    Goadsby, P J; Hoskin, K L; Storer, R J;

    2002-01-01

    There is a considerable literature to suggest that adenosine A1 receptor agonists may have anti-nociceptive effects, and we sought to explore the role of adenosine A1 receptors in a model of trigeminovascular nociceptive transmission. Cats were anaesthetized (alpha-chloralose 60 mg/kg, intraperit......There is a considerable literature to suggest that adenosine A1 receptor agonists may have anti-nociceptive effects, and we sought to explore the role of adenosine A1 receptors in a model of trigeminovascular nociceptive transmission. Cats were anaesthetized (alpha-chloralose 60 mg...

  11. Pretreatment with adenosine and adenosine A1 receptor agonist protects against intestinal ischemia-reperfusion injury in rat

    V Haktan Ozacmak; Hale Sayan

    2007-01-01

    AIM: To examine the effects of adenosine and A1 receptor activation on reperfusion-induced small intestinal injury.METHODS: Rats were randomized into groups with sham operation, ischemia and reperfusion, and systemic treatments with either adenosine or 2-chloro-N6-cyclopentyladenosine, A1 receptor agonist or 8-cyclopentyl-1,3-dipropylxanthine, A1 receptor antagonist, plus adenosine before ischemia. Following reperfusion, contractions of ileum segments in response to KCl, carbachol and substance P were recorded. Tissue myeloperoxidase,malondialdehyde, and reduced glutathione levels were measured.RESULTS: Ischemia significantly decreased both contraction and reduced glutathione level which were ameliorated by adenosine and agonist administration. Treatment also decreased neutrophil infiltration and membrane lipid peroxidation. Beneficial effects of adenosine were abolished by pretreatment with A1 receptor antagonist.CONCLUSION: The data suggest that adenosine and A1 receptor stimulation attenuate ischemic intestinal injury via decreasing oxidative stress, lowering neutrophil infiltration, and increasing reduced glutathione content.

  12. Intravenous adenosine and radiopharmaceutical injection in the same line was feasible in adenosine stress myocardial perfusion imaging

    Adenosine stress myocardial perfusion imaging was performed with an intravenous adenosine and radiopharmaceutical injection in the same line. A syringe containing 720 μ/kg of adenosine in 40 ml of saline was prepared and injected at the constant infusion rate of 400 ml/h. Adenosine was temporarily stopped by the stopcock when 1.5 ml of thallium was injected for 0.5 second from the three-way stopcock with two ways opened. Thereafter, the stopcock was returned to the original position in 0.5 second, and adenosine flow returned to the constant flow rate again. In this method, 0.75% of adenosine total dose was injected at a rate of 3.0 ml/s and adenosine was stopped for 3.6 second. There were no significant differences in either effects and adverse events of adenosine between this method and two intravenous injection line methods. Adenosine stress in one venous line method would be an easy method maintaining the dose effect and safety. (author)

  13. Mechanism of protection of adenosine from sulphate radical anion and repair of adenosine radicals by caffeic acid in aqueous solution

    M Sudha Swaraga; L Charitha; M Adinarayana

    2005-07-01

    The photooxidation of adenosine in presence of peroxydisulphate (PDS) has been studied by spectrophotometrically measuring the absorbance of adenosine at 260 nm. The rates of oxidation of adenosine by sulphate radical anion have been determined in the presence of different concentrations of caffeic acid. Increase in [caffeic acid] is found to decrease the rate of oxidation of adenosine suggesting that caffeic acid acts as an efficient scavenger of $SO_{4}^{\\bullet-}$ and protects adenosine from it. Sulphate radical anion competes for adenosine as well as for caffeic acid. The quantum yields of photooxidation of adenosine have been calculated from the rates of oxidation of adenosine and the light intensity absorbed by PDS at 254 nm, the wavelength at which PDS is activated to sulphate radical anion. From the results of experimentally determined quantum yields (exptl) and the quantum yields calculated (cal) assuming caffeic acid acting only as a scavenger of $SO_{4}^{\\bullet-}$ show that exptl values are lower than cal values. The ' values, which are experimentally found quantum yield values at each caffeic acid concentration and corrected for $SO_{4}^{\\bullet-}$ scavenging by caffeic acid, are also found to be greater than exptl values. These observations suggest that the transient adenosine radicals are repaired by caffeic acid in addition to scavenging of sulphate radical anions.

  14. Characterization of adenosine binding proteins in human placental membranes

    We have characterized two adenosine binding proteins in human placenta. In membranes, one site is detected with [3H] -N-ethylcarboxamidoadenosine ([3H]NECA). This site is similar to the adenosine A2 receptor. We call this site the adenosine A2-like binding site. In detergent extracts, the second site is detected and has the characteristics of an adenosine A1 receptor. The soluble adenosine A2-like binding site cannot be detected without a rapid assay. Binding to the adenosine A1 receptor with [3H]-2-chloroadenosine and [3H]NECA is time dependent, saturable, and reversible. Equilibrium displacement analysis with adenosine agonists reveals an A1 specificity: 2-chloroadenosine > R-phenylisopropyladenosine > 5'-N-ethylcarboxamidoadenosine. The antagonist potency order is 1,3-diethyl-8-phenylxanthine > isobutylmethylxanthine > theophylline. Competition analysis of membranes with the A,-selective ligands [3H]-cyclohexyladenosine [3H] cylopentylxanthine revealed adenosine A1 agonist and antagonist potency orders. We have purified the adenosine A2-like binding site. The adenosine A2-like binding site is an ubiquitous major cellular protein. It is glycosylated, highly asymmetric, and acidic. The native protein is an homodimer with a subunit molecular mass of 98 kDa. The sedimentation coefficient and partial specific volume of the binding complex are 6.9 s and 0.698 ml/g, respectively. The Stokes' radius is 70 Angstrom. The native molecular mass of the detergent-protein complex is 230 kDa. The adenosine A2-like binding site has an agonist potency order of 5'-N-ethylcarboxamidoadenosine > 2-chloroadenosine >> R-phenylisopropyladenosine and an antagonist potency order of isobutylmethylxanthine > theophylline >> 1,3-diethyl-8-phenylxanthine

  15. Characterization of adenosine binding proteins in human placental membranes

    Hutchison, K.A.

    1989-01-01

    We have characterized two adenosine binding proteins in human placenta. In membranes, one site is detected with ({sup 3}H) -N-ethylcarboxamidoadenosine (({sup 3}H)NECA). This site is similar to the adenosine A{sub 2} receptor. We call this site the adenosine A{sub 2}-like binding site. In detergent extracts, the second site is detected and has the characteristics of an adenosine A{sub 1} receptor. The soluble adenosine A{sub 2}-like binding site cannot be detected without a rapid assay. Binding to the adenosine A{sub 1} receptor with ({sup 3}H)-2-chloroadenosine and ({sup 3}H)NECA is time dependent, saturable, and reversible. Equilibrium displacement analysis with adenosine agonists reveals an A{sub 1} specificity: 2-chloroadenosine > R-phenylisopropyladenosine > 5{prime}-N-ethylcarboxamidoadenosine. The antagonist potency order is 1,3-diethyl-8-phenylxanthine > isobutylmethylxanthine > theophylline. Competition analysis of membranes with the A,-selective ligands ({sup 3}H)-cyclohexyladenosine ({sup 3}H) cylopentylxanthine revealed adenosine A{sub 1} agonist and antagonist potency orders. We have purified the adenosine A{sub 2}-like binding site. The adenosine A{sub 2}-like binding site is an ubiquitous major cellular protein. It is glycosylated, highly asymmetric, and acidic. The native protein is an homodimer with a subunit molecular mass of 98 kDa. The sedimentation coefficient and partial specific volume of the binding complex are 6.9 s and 0.698 ml/g, respectively. The Stokes' radius is 70 {Angstrom}. The native molecular mass of the detergent-protein complex is 230 kDa. The adenosine A{sub 2}-like binding site has an agonist potency order of 5'-N-ethylcarboxamidoadenosine > 2-chloroadenosine >> R-phenylisopropyladenosine and an antagonist potency order of isobutylmethylxanthine > theophylline >> 1,3-diethyl-8-phenylxanthine.

  16. High-dose adenosine overcomes the attenuation of myocardial perfusion reserve caused by caffeine.

    Reyes, E.; Loong, C Y; Harbinson, Mark; Donovan, J; Anagnostopoulos, C.; Underwood, S. R.

    2008-01-01

    Objectives:We studied whether an increase in adenosine dose overcomes caffeine antagonism on adenosine-mediated coronary vasodilation.Background:Caffeine is a competitive antagonist at the adenosine receptors, but it is unclear whether caffeine in coffee alters the actions of exogenous adenosine, and whether the antagonism can be surmounted by increasing the adenosine dose.Methods:Myocardial perfusion scintigraphy (MPS) was used to assess adenosine-induced hyperemia in 30 patients before (bas...

  17. Adenosine and its receptors as therapeutic targets: An overview

    Sachdeva, Sakshi; Gupta, Monika

    2012-01-01

    The main goal of the authors is to present an overview of adenosine and its receptors, which are G-protein coupled receptors. The four known adenosine receptor subtypes are discussed along with the therapeutic potential indicating that these receptors can serve as targets for various dreadful diseases.

  18. Effect of theophylline on adenosine production in the canine myocardium

    Adenosine is thought to participate in local regulation of coronary blood flow. However, competitive antagonists of adenosine fail to block myocardial active hyperemia. The authors examined the effect of locally administered theophylline on active hyperemia and myocardial adenosine production during intracoronary isoproterenol infusion in the dog heart. Isoproterenol decreased coronary resistance and increased myocardial adenosine production. Infusion of theophylline at a rate that attenuated the vasodilator response to exogenously administered adenosine failed to attenuate the increase in coronary blood flow produced by isoproterenol. However, theophylline plus isoproterenol production greater increases in myocardial adensine production than isoproterenol alone. The curves relating resistance and adenosine in the presence of theophylline fell to the right of those in the absence of theophylline. These findings suggest that the failure of theophylline to attenuate isoproterenol hyperemia in the dog heart results at least in part from an increase in adenosine concentration at the arteriole to a level beyond that blocked by this competitive antagonist and that adenosine may in fact play a role in isoproterenol-induced active hyperemia

  19. A High-Affinity Adenosine Kinase from Anopheles Gambiae

    M Cassera; M Ho; E Merino; E Burgos; A Rinaldo-Matthis; S Almo; V Schramm

    2011-12-31

    Genome analysis revealed a mosquito orthologue of adenosine kinase in Anopheles gambiae (AgAK; the most important vector for the transmission of Plasmodium falciparum in Africa). P. falciparum are purine auxotrophs and do not express an adenosine kinase but rely on their hosts for purines. AgAK was kinetically characterized and found to have the highest affinity for adenosine (K{sub m} = 8.1 nM) of any known adenosine kinase. AgAK is specific for adenosine at the nucleoside site, but several nucleotide triphosphate phosphoryl donors are tolerated. The AgAK crystal structure with a bound bisubstrate analogue Ap{sub 4}A (2.0 {angstrom} resolution) reveals interactions for adenosine and ATP and the geometry for phosphoryl transfer. The polyphosphate charge is partly neutralized by a bound Mg{sup 2+} ion and an ion pair to a catalytic site Arg. The AgAK structure consists of a large catalytic core in a three-layer {alpha}/{beta}/{alpha} sandwich, and a small cap domain in contact with adenosine. The specificity and tight binding for adenosine arise from hydrogen bond interactions of Asn14, Leu16, Leu40, Leu133, Leu168, Phe168, and Thr171 and the backbone of Ile39 and Phe168 with the adenine ring as well as through hydrogen bond interactions between Asp18, Gly64, and Asn68 and the ribosyl 2'- and 3'-hydroxyl groups. The structure is more similar to that of human adenosine kinase (48% identical) than to that of AK from Toxoplasma gondii (31% identical). With this extraordinary affinity for AgAK, adenosine is efficiently captured and converted to AMP at near the diffusion limit, suggesting an important role for this enzyme in the maintenance of the adenine nucleotide pool. mRNA analysis verifies that AgAK transcripts are produced in the adult insects.

  20. Extracellular formation and uptake of adenosine during skeletal muscle contraction in the rat: role of adenosine transporters.

    Lynge, J; Juel, C; Hellsten, Y

    2001-12-01

    1. The existence of adenosine transporters in plasma membrane giant vesicles from rat skeletal muscles and in primary skeletal muscle cell cultures was investigated. In addition, the contribution of intracellularly or extracellularly formed adenosine to the overall extracellular adenosine concentration during muscle contraction was determined in primary skeletal muscle cell cultures. 2. In plasma membrane giant vesicles, the carrier-mediated adenosine transport demonstrated saturation kinetics with Km = 177 +/- 36 microM and Vmax = 1.9 +/- 0.2 nmol x ml(-1) x s(-1) (0.7 nmol (mg protein)(-1) x s(-1)). The existence of an adenosine transporter was further evidenced by the inhibition of the carrier-mediated adenosine transport in the presence of NBMPR (nitrobenzylthioinosine; 72% inhibition) or dipyridamol (64% inhibition; P electro-stimulation of skeletal muscle is due to production of adenosine in the extracellular space of skeletal muscle and that adenosine is taken up rather than released by the skeletal muscle cells during contraction. PMID:11731589

  1. The role of adenosine receptors and endogenous adenosine in citalopram-induced cardiovascular toxicity

    Kubilay Oransay; Nil Hocaoglu; Mujgan Buyukdeligoz; Yesim Tuncok; Sule Kalkan

    2014-01-01

    Aim: We investigated the role of adenosine in citalopram-induced cardiotoxicity. Materials and Methods: Protocol 1: Rats were randomized into four groups. Sodium cromoglycate was administered to rats. Citalopram was infused after the 5% dextrose, 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX; A 1 receptor antagonist), 8-(-3-chlorostyryl)-caffeine (CSC; A 2a receptor antagonist), or dimethyl sulfoxide (DMSO) administrations. Protocol 2: First group received 5% dextrose intraperitoneally 1 hour...

  2. Modulation of bladder function by luminal adenosine turnover and A1 receptor activation

    Prakasam, H. Sandeep; Herrington, Heather; Roppolo, James R.; Jackson, Edwin K.; Apodaca, Gerard

    2012-01-01

    The bladder uroepithelium transmits information to the underlying nervous and musculature systems, is under constant cyclical strain, expresses all four adenosine receptors (A1, A2A, A2B, and A3), and is a site of adenosine production. Although adenosine has a well-described protective effect in several organs, there is a lack of information about adenosine turnover in the uroepithelium or whether altering luminal adenosine concentrations impacts bladder function or overactivity. We observed ...

  3. Distribution of adenosine receptors in human sclera fibroblasts

    Cui, Dongmei; Trier, Klaus; Chen, Xiang; Zeng, Junwen; Yang, Xiao; Hu, Jianmin; Ge, Jian

    2008-01-01

    Purpose Systemic treatment with adenosine receptor antagonists has been reported to affect the biochemistry and ultrastructure of rabbit sclera. This study was conducted to determine whether adenosine receptors (ADORs) are present in human scleral fibroblasts (HSF). Methods Primary HSF were cultured in vitro and identified with anti-vimentin, anti-keratin, anti-desmin, and anti-S-100 antibodies. Confocal fluorescence microscopy was used to study the distribution of ADORs in the HSF cell lines...

  4. Proton transfer in oxidized adenosine self-aggregates.

    Capobianco, Amedeo; Caruso, Tonino; Celentano, Maurizio; La Rocca, Mario Vincenzo; Peluso, Andrea

    2013-10-14

    The UV-vis and the IR spectra of derivativized adenosine in dichloromethane have been recorded during potentiostatic oxidation at an optically transparent thin layer electrode. Oxidized adenosine shows a broad Zundel like absorption extending from 2800 up to 3600 cm(-1), indicating that a proton transfer process is occurring. Theoretical computations predict that proton transfer is indeed favored in oxidized 1:1 self-association complexes and allow to assign all the observed transient spectroscopic signals. PMID:24116647

  5. Regulation of Adenosine Deaminase on Induced Mouse Experimental Autoimmune Uveitis.

    Liang, Dongchun; Zuo, Aijun; Zhao, Ronglan; Shao, Hui; Kaplan, Henry J; Sun, Deming

    2016-03-15

    Adenosine is an important regulator of the immune response, and adenosine deaminase (ADA) inhibits this regulatory effect by converting adenosine into functionally inactive molecules. Studies showed that adenosine receptor agonists can be anti- or proinflammatory. Clarification of the mechanisms that cause these opposing effects should provide a better guide for therapeutic intervention. In this study, we investigated the effect of ADA on the development of experimental autoimmune uveitis (EAU) induced by immunizing EAU-prone mice with a known uveitogenic peptide, IRBP1-20. Our results showed that the effective time to administer a single dose of ADA to suppress induction of EAU was 8-14 d postimmunization, shortly before EAU expression; however, ADA treatment at other time points exacerbated disease. ADA preferentially inhibited Th17 responses, and this effect was γδ T cell dependent. Our results demonstrated that the existing immune status strongly influences the anti- or proinflammatory effects of ADA. Our observations should help to improve the design of ADA- and adenosine receptor-targeted therapies. PMID:26856700

  6. Antagonism by theophylline of respiratory inhibition induced by adenosine.

    Eldridge, F L; Millhorn, D E; Kiley, J P

    1985-11-01

    The effects on respiration of an analogue of adenosine, L-2-N6-(phenylisopropyl)adenosine (PIA), and of the methylxanthine, theophylline, were determined in 19 vagotomized glomectomized cats whose end-tidal PCO2 was kept constant by means of a servo-controlled ventilator. Integrated phrenic nerve activity was used to represent respiratory output. Our results show that PIA, whether given systemically or into the third cerebral ventricle, depressed respiration. Systemically administered theophylline stimulated respiration. Theophylline given intravenously, or into the third ventricle not only reversed the depressive effects of previously administered PIA but caused further increases of respiration above the control level. Prior systemic administration of theophylline blocked both respiratory and hypotensive effects of subsequently administered PIA. Effects of either agent on medullary extracellular fluid pH did not explain the results. We conclude that the adenosine analogue PIA, acts to inhibit neurons in the brain that are involved in the control of respiration and that its effects are blocked by theophylline. We suggest that adenosine acts as a tonic modulator of respiration and that theophylline stimulates breathing by competitive antagonism of adenosine at neuronal receptor sites. PMID:4066573

  7. Modification of survival of gamma irradiated mice by adenosine nucleotides

    The administration prior to irradiation of adenosine triphosphate (ATP) or other adenosine nucleotides, singly or in combination, increased the radioresistance of mice. Post-irradiation treatment with the adenosine nucleotides had no effect on the survival of the irradiated mice. Dose reduction factors of 2.32 could be obtained by pretreatment of mice with the following combination of protective agents: S-2(4-aminobutylamino)ethyl phosphorothioic aced (WR 2822), cysteamine (MEA) and ATP. Since cyclic AMP levels were unchanged in the spleen or gut by administration of cysteamine and other protectors it is unlikely that the increase in protection was due to changes in cyclic AMP levels. The calcium salt of ATP provided a higher level of protection than the ATP alone, indicating that the protective mechanism of ATP is probably not related to anoxia. (orig.)

  8. Thallium-201 scintigraphy of the myocardium in connection with adenosine

    It is shown that thallium-201 SPECT studies of the myocardium performed subsequent to intravenous infusion of adenosine provide results at least as valuable as those from exercise thallium-201 scintigraphy in the diagnosis of coronary artery disease. The infusion of adenosine offers great advantages over exercise studies in that it is a standardized procedure uninfluenced by a patient's physical fitness, which can thus be used in all cases. There are quite a number of clinically tolerable untoward reactions that may be associated with discomfort but do not warrant discontinuation of the procedure. Serious, verifiable side-effects are rare and disappear immediately on termination of the infusion. The most recent research in this field has shown that newly developed compounds of 99mTc are also suitable for radionuclide studies of the myocardium with adenosine vasodilation. (orig.)

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

    Full Text Available 17056121 Shaping of monocyte and macrophage function by adenosine receptors. Hasko G, Pacher...e Shaping of monocyte and macrophage function by adenosine receptors. Authors Hasko G, Pacher

  10. Investigating real-time activation of adenosine receptors by bioluminescence resonance energy transfer technique

    Huang, Yimei; Yang, Hongqin; Zheng, Liqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen

    2013-02-01

    Adenosine receptors play important roles in many physiological and pathological processes, for example regulating myocardial oxygen consumption and the release of neurotransmitters. The activations of adenosine receptors have been studied by some kinds of techniques, such as western blot, immunohistochemistry, etc. However, these techniques cannot reveal the dynamical response of adenosine receptors under stimulation. In this paper, bioluminescence resonance energy transfer technique was introduced to study the real-time activation of adenosine receptors by monitoring the dynamics of cyclic adenosine monophosphate (cAMP) level. The results showed that there were significant differences between adenosine receptors on real-time responses under stimulation. Moreover, the dynamics of cAMP level demonstrated that competition between adenosine receptors existed. Taken together, our study indicates that monitoring the dynamics of cAMP level using bioluminescence resonance energy transfer technique could be one potential approach to investigate the mechanism of competitions between adenosine receptors.

  11. Tween 20-stabilized gold nanoparticles combined with adenosine triphosphate-BODIPY conjugates for the fluorescence detection of adenosine with more than 1000-fold selectivity

    Graphical abstract: A simple, enzyme-free, label-free, sensitive and selective system was developed for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles as an efficient quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate and as a recognition element for adenosine. - Highlights: • The proposed method can detect adenosine with more than 1000-fold selectivity. • The analysis of adenosine is rapid (∼6 min) using the proposed method. • This method provided better sensitivity for adenosine as compared to aptamer-based sensors. • This method can be applied for the determination of adenosine in urine. - Abstract: This study describes the development of a simple, enzyme-free, label-free, sensitive, and selective system for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles (Tween 20-AuNPs) as an efficient fluorescence quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate (BODIPY-ATP) and as a recognition element for adenosine. BODIPY-ATP can interact with Tween 20-AuNPs through the coordination between the adenine group of BODIPY-ATP and Au atoms on the NP surface, thereby causing the fluorescence quenching of BODIPY-ATP through the nanometal surface energy transfer (NSET) effect. When adenosine attaches to the NP surface, the attached adenosine exhibits additional electrostatic attraction to BODIPY-ATP. As a result, the presence of adenosine enhances the efficiency of AuNPs in fluorescence quenching of BODIPY-ATP. The AuNP-induced fluorescence quenching of BODIPY-ATP progressively increased with an increase in the concentration of adenosine; the detection limit at a signal-to-noise ratio of 3 for adenosine was determined to be 60 nM. The selectivity of the proposed system was more than 1000-fold for adenosine over any adenosine analogs and other nucleotides. The proposed system combined with a phenylboronic acid-containing column was successfully applied to the

  12. No role of interstitial adenosine in insulin-mediated vasodilation

    Dela, F; Stallknecht, B

    1999-01-01

    healthy subjects (H) and in four subjects with a complete, high (C5-C6/7) spinal cord injury (SCI) a hyperinsulinaemic (480 mU min-1 kg-1), isoglycaemic clamp was performed. SCI subjects were included as it has been proposed that adenosine and adenine nucleotides may be released from nerve endings in the...... skeletal muscle. Adenosine concentrations in the extracellular fluid (ECF) of skeletal muscle in the thigh were measured by means of the microdialysis technique. Leg blood flow (LBF) was measured by termodilution. In response to insulin infusion, LBF always increased (P < 0.05) (from 228 +/- 25 and 318...

  13. Why do premature newborn infants display elevated blood adenosine levels?

    Panfoli, Isabella; Cassanello, Michela; Bruschettini, Matteo; Colella, Marina; Cerone, Roberto; Ravera, Silvia; Calzia, Daniela; Candiano, Giovanni; Ramenghi, Luca

    2016-05-01

    Our preliminary data show high levels of adenosine in the blood of very low birth weight (VLBW) infants, positively correlating to their prematurity (i.e. body weight class). This prompted us to look for a mechanism promoting such impressive adenosine increase. We hypothesized a correlation with oxygen challenge. In fact, it is recognized that either oxygen lack or its excess contribute to the pathogenesis of the injuries of prematurity, such as retinopathy (ROP) and periventricular white matter lesions (PWMI). The optimal concentration of oxygen for resuscitation of VLBW infants is currently under revision. We propose that the elevated adenosine blood concentrations of VLBW infants recognizes two sources. The first could be its activity-dependent release from unmyelinated brain axons. Adenosine in this respect would be an end-product of the hypometabolic VLBW newborn unmyelinated axon intensely firing in response to the environmental stimuli consequent to premature birth. Adenosine would be eventually found in the blood due to blood-brain barrier immaturity. In fact, adenosine is the primary activity-dependent signal promoting differentiation of premyelinating oligodendrocyte progenitor cells (OPC) into myelinating cells in the Central Nervous System, while inhibiting their proliferation and inhibiting synaptic function. The second, would be the ecto-cellular ATP synthesized by the endothelial cell plasmalemma exposed to ambient oxygen concentrations due to premature breathing, especially in lung. ATP would be rapidly transformed into adenosine by the ectonucleotidase activities such as NTPDase I (CD39), and NT5E (CD73). An ectopic extra-mitochondrial aerobic ATP synthetic ability was reported in many cell plasma-membranes, among which endothelial cells. The potential implications of the cited hypotheses for the neonatology area would be great. The amount of oxygen administration for reviving of newborns would find a molecular basis for its assessment. VLBW

  14. Cyclic adenosine monophosphate phosphodiesterase in brain: effect on anxiety.

    Beer, B; Chasin, M; Clody, D E; Vogel, J R

    1972-04-28

    Drugs that reduce anxiety may be mediated by cyclic adenosine monophosphate in the brain because (i) potent anxiety-reducing drugs are also potent inhibitors of brain phosphodiesterase activity; (ii) dibutyryl cyclic adenosine monophosphate has the ability to reduce anxiety; (iii) the methylxanthines show significant anxiety-reducing effects; (iv) theophylline and chlordiazepoxide produce additive anxiety-reducing activity; and (v) there is a significant correlation between the anxiety-reducing property of drugs and their ability to inhibit phosphodiesterase activity in the brain. PMID:4402069

  15. Cytotoxic purine nucleoside analogues bind to A1, A2A and A3 adenosine receptors

    Jensen, Kyle; Johnson, L’Aurelle A.; Jacobson, Pamala A.; Kachler, Sonja; Kirstein, Mark N.; Lamba, Jatinder; Klotz, Karl-Norbert

    2012-01-01

    Fludarabine, clofarabine and cladribine are anti-cancer agents which are analogues of the purine nucleoside adenosine. These agents have been associated with cardiac and neurological toxicities. Because these agents are analogues of adenosine, they may act through adenosine receptors to elicit their toxic effects. The objective of this study was to evaluate the ability of cytotoxic nucleoside analogues to bind and activate adenosine receptor subtypes (A1, A2A, A2B, and A3). Radioligand bindin...

  16. Adenosine and a selective A2a receptor agonist regadenoson used in myocardial stress test

    Adenosine pharmacological myocardial stress test has been widely used in clinic. However, the side effects related with adenosine administration has been an issue of controversy. Current Phase Ⅲ study of regadenoson, a selective A2a receptor agonist, reveals its potential to substitute adenosine as a new agent for pharmacological myocardial stress test. This review briefs adenosine and regadenoson and their clinical utilities in myocardial stress test. (authors)

  17. Adenosine as a signaling molecule in the retina: biochemical and developmental aspects

    ROBERTO PAES-DE-CARVALHO

    2002-01-01

    The nucleoside adenosine plays an important role as a neurotransmitter or neuromodulator in the central nervous system, including the retina. In the present paper we review compelling evidence showing that adenosine is a signaling molecule in the developing retina. In the chick retina, adenosine transporters are present since early stages of development before the appearance of adenosine A1 receptors modulating dopamine-dependent adenylate cyclase activity or A2 receptors that directly activa...

  18. Adenosine transiently modulates stimulated dopamine release in the caudate putamen via A1 receptors

    Ross, Ashley E.; Venton, B. Jill

    2014-01-01

    Adenosine modulates dopamine in the brain via A1 and A2A receptors, but that modulation has only been characterized on a slow time scale. Recent studies have characterized a rapid signaling mode of adenosine that suggests a possible rapid modulatory role. Here, fast-scan cyclic voltammetry was used to characterize the extent to which transient adenosine changes modulate stimulated dopamine release (5 pulses at 60 Hz) in rat caudate putamen brain slices. Exogenous adenosine was applied and dop...

  19. The adenosine metabolite inosine is a functional agonist of the adenosine A2A receptor with a unique signaling bias.

    Welihinda, Ajith A; Kaur, Manmeet; Greene, Kelly; Zhai, Yongjiao; Amento, Edward P

    2016-06-01

    Inosine is an endogenous purine nucleoside that is produced by catabolism of adenosine. Adenosine has a short half-life (approximately 10s) and is rapidly deaminated to inosine, a stable metabolite with a half-life of approximately 15h. Resembling adenosine, inosine acting through adenosine receptors (ARs) exerts a wide range of anti-inflammatory and immunomodulatory effects in vivo. The immunomodulatory effects of inosine in vivo, at least in part, are mediated via the adenosine A2A receptor (A2AR), an observation that cannot be explained fully by in vitro pharmacological characterization of inosine at the A2AR. It is unclear whether the in vivo effects of inosine are due to inosine or a metabolite of inosine engaging the A2AR. Here, utilizing a combination of label-free, cell-based, and membrane-based functional assays in conjunction with an equilibrium agonist-binding assay we provide evidence for inosine engagement at the A2AR and subsequent activation of downstream signaling events. Inosine-mediated A2AR activation leads to cAMP production with an EC50 of 300.7μM and to extracellular signal-regulated kinase-1 and -2 (ERK1/2) phosphorylation with an EC50 of 89.38μM. Our data demonstrate that inosine produces ERK1/2-biased signaling whereas adenosine produces cAMP-biased signaling at the A2AR, highlighting pharmacological differences between these two agonists. Given the in vivo stability of inosine, our data suggest an additional, previously unrecognized, mechanism that utilizes inosine to functionally amplify and prolong A2AR activation in vivo. PMID:26903141

  20. Contraction induced secretion of VEGF from skeletal muscle cells is mediated by adenosine

    Høier, Birgitte; Olsen, Karina; Nyberg, Michael Permin; Bangsbo, Jens; Hellsten, Ylva

    2010-01-01

    and during knee extensor exercise. The dialysate was analyzed for content of VEGF protein and adenosine. The mechanism of VEGF secretion from muscle cells in culture was examined in resting and electro stimulated cells, and in response to the adenosine analogue NECA, and the adenosine A(2A) receptor...

  1. Searching Inhibitors of Adenosine Kinase by Simulation Methods

    ZHU Rui-Xin; ZHANG Xing-Long; DONG Xi-Cheng; CHEN Min-Bo

    2006-01-01

    Searching new inhibitors of adenosine kinase (AK) is still drawing attention of experimental scientists. A better and solid model is here proposed by means of simulation methods from different ways, the direct analysis of receptor itself, the conventional 3D-QSAR methods and the integration of docking method and the conventional QSAR analysis.

  2. Adenosine receptor modulation of seizure susceptibility in rats

    Adenosine is considered to be a neuromodulator or cotransmitter in the periphery and CNS. This neuromodulatory action of adenosine may be observed as an anticonvulsant effect. Dose-response curves for R-phenylisopropyladenosine (PIA), cycohexyladenosine (CHA), 2-chloroadenosine (2-ClAdo), N-ethylcarboxamidoadenosine (NECA) and S-PIA were generated against PTZ seizure thresholds in the rat. The rank order of potency for adenosine agonists to elevate PTZ seizure threshold was R-PIA > 2-ClAdo > NECA > CHA > S-PIA. R-PIA was approximately 80-fold more potent than S-PIA. This 80-fold difference in potency between the diasteriomers of PIA was consistent with an A1 adenoise receptor-mediated response. The anticonvulsant action of 2-ClAdo was reversed by pretreatment with theoplylline. Chronic administration of theophylline significantly increased the specific binding of 3H-cyclohexyladenosine in membranes of the cerebral cortex and cerebellum of the rat. Chronic exposure to theophylline produced a significant increase in the densities of both the high- and low-affinity forms of A1 adenosine receptors in the cerebral cortex

  3. Mechanism of A2 adenosine receptor activation. I. Blockade of A2 adenosine receptors by photoaffinity labeling

    Lohse, M.J.; Klotz, K.N.; Schwabe, U.

    1991-04-01

    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.

  4. Metabolic changes of cultured DRG neurons induced by adenosine using confocal microscopy imaging

    Zheng, Liqin; Huang, Yimei; Chen, Jiangxu; Wang, Yuhua; Yang, Hongqin; Zhang, Yanding; Xie, Shusen

    2012-12-01

    Adenosine exerts multiple effects on pain transmission in the peripheral nervous system. This study was performed to use confocal microscopy to evaluate whether adenosine could affect dorsal root ganglia (DRG) neurons in vitro and test which adenosine receptor mediates the effect of adenosine on DRG neurons. After adding adenosine with different concentration, we compared the metabolic changes by the real time imaging of calcium and mitochondria membrane potential using confocal microscopy. The results showed that the effect of 500 μM adenosine on the metabolic changes of DRG neurons was more significant than others. Furthermore, four different adenosine receptor antagonists were used to study which receptor mediated the influences of adenosine on the cultured DRG neurons. All adenosine receptor antagonists especially A1 receptor antagonist (DPCPX) had effect on the Ca2+ and mitochondria membrane potential dynamics of DRG neurons. The above studies demonstrated that the effect of adenosine which may be involved in the signal transmission on the sensory neurons was dose-dependent, and all the four adenosine receptors especially the A1R may mediate the transmission.

  5. Adenosine contributes to blood flow regulation in the exercising human leg by increasing prostaglandin and nitric oxide formation

    Mortensen, Stefan; Nyberg, Michael; Thaning, Pia;

    2009-01-01

    Adenosine can induce vasodilation in skeletal muscle, but to what extent adenosine exerts its effect via formation of other vasodilators and whether there is redundancy between adenosine and other vasodilators remain unclear. We tested the hypothesis that adenosine, prostaglandins, and NO act in...

  6. Adenosine-mediated modulation of ventral horn interneurons and spinal motoneurons in neonatal mice.

    Witts, Emily C; Nascimento, Filipe; Miles, Gareth B

    2015-10-01

    Neuromodulation allows neural networks to adapt to varying environmental and biomechanical demands. Purinergic signaling is known to be an important modulatory system in many parts of the CNS, including motor control circuitry. We have recently shown that adenosine modulates the output of mammalian spinal locomotor control circuitry (Witts EC, Panetta KM, Miles GB. J Neurophysiol 107: 1925-1934, 2012). Here we investigated the cellular mechanisms underlying this adenosine-mediated modulation. Whole cell patch-clamp recordings were performed on ventral horn interneurons and motoneurons within in vitro mouse spinal cord slice preparations. We found that adenosine hyperpolarized interneurons and reduced the frequency and amplitude of synaptic inputs to interneurons. Both effects were blocked by the A1-type adenosine receptor antagonist DPCPX. Analysis of miniature postsynaptic currents recorded from interneurons revealed that adenosine reduced their frequency but not amplitude, suggesting that adenosine acts on presynaptic receptors to modulate synaptic transmission. In contrast to interneurons, recordings from motoneurons revealed an adenosine-mediated depolarization. The frequency and amplitude of synaptic inputs to motoneurons were again reduced by adenosine, but we saw no effect on miniature postsynaptic currents. Again these effects on motoneurons were blocked by DPCPX. Taken together, these results demonstrate differential effects of adenosine, acting via A1 receptors, in the mouse spinal cord. Adenosine has a general inhibitory action on ventral horn interneurons while potentially maintaining motoneuron excitability. This may allow for adaptation of the locomotor pattern generated by interneuronal networks while helping to ensure the maintenance of overall motor output. PMID:26311185

  7. Abiotic regioselective phosphorylation of adenosine with borate in formamide.

    Furukawa, Yoshihiro; Kim, Hyo-Joong; Hutter, Daniel; Benner, Steven A

    2015-04-01

    Nearly 40 years ago, Schoffstall and his coworkers used formamide as a solvent to permit the phosphorylation of nucleosides by inorganic phosphate to give nucleoside phosphates, which (due to their thermodynamic instability with respect to hydrolysis) cannot be easily created in water by an analogous phosphorylation (the "water problem" in prebiotic chemistry). More recently, we showed that borate could stabilize certain carbohydrates against degradation (the "asphalt problem"). Here, we combine the two concepts to show that borate can work in formamide to guide the reactivity of nucleosides under conditions where they are phosphorylated. Specifically, reaction of adenosine in formamide with inorganic phosphate and pyrophosphate in the presence of borate gives adenosine-5'-phosphate as the only detectable phosphorylated product, with formylation (as opposed to hydrolysis) being the competing reaction. PMID:25826074

  8. Effects of adenosine metabolism in astrocytes on central nervous system oxygen toxicity.

    Chen, Yu-liang; Zhang, Ya-nan; Wang, Zhong-zhuang; Xu, Wei-gang; Li, Run-ping; Zhang, Jun-dong

    2016-03-15

    Hyperbaric oxygen (HBO) is widely used in military operations, especially underwater missions. However, prolonged and continuous inhalation of HBO can cause central nervous system oxygen toxicity (CNS-OT), which greatly limits HBO's application. The regulation of astrocytes to the metabolism of adenosine is involved in epilepsy. In our study, we aimed to observe the effects of HBO exposure on the metabolism of adenosine in the brain. Furthermore, we aimed to confirm the possible mechanism underlying adenosine's mediation of the CNS-OT. Firstly, anesthetized rats exposed to 5 atm absolute HBO for 80 min. The concentrations of extracellular adenosine, ATP, ADP, and AMP were detected. Secondly, free-moving rats were exposed to HBO at the same pressure for 20 min, and the activities of 5'-nucleotidase and ADK in brain tissues were measured. For the mechanism studies, we observed the effects of a series of different doses of drugs related to adenosine metabolism on the latency of CNS-OT. Results showed HBO exposure could increase adenosine content by inhibiting ADK activity and improving 5'-nucleotidase activity. And adenosine metabolism during HBO exposure may be a protective response against HBO-induced CNS-OT. Moreover, the improvement of adenosine concentration, activation of adenosine A1R, or suppression of ADK and adenosine A2AR, which are involved in the prevention of HBO-induced CNS-OT. This is the first study to demonstrate HBO exposure regulated adenosine metabolism in the brain. Adenosine metabolism and adenosine receptors are related to HBO-induced CNS-OT development. These results will provide new potential targets for the termination or the attenuation of CNS-OT. PMID:26806404

  9. The emerging role of adenosine deaminases in insects

    Doleželová, Eva; Žurovec, Michal; Doležal, T.; Šimek, Petr; Bryant, P. J.

    2005-01-01

    Roč. 35, č. 5 (2005), s. 381-389. ISSN 0965-1748 R&D Projects: GA ČR(CZ) GA204/04/1205; GA AV ČR(CZ) IAA5007107 Grant ostatní: United States National Science Foundation(US) 440860-21565 Institutional research plan: CEZ:AV0Z50070508 Keywords : adenosine deaminase * ADA * growth factor Subject RIV: ED - Physiology Impact factor: 2.733, year: 2005

  10. Adenosine receptors and stress : Studies using methylmercury, caffeine and hypoxia

    Björklund, Olga

    2008-01-01

    Brain development is a precisely organized process that can be disturbed by various stress factors present in the diet (e.g. exposure to xenobiotics) as well as insults such as decreased oxygen supply. The consequent adverse changes in nervous system function may not necessarily be apparent until a critical age when neurodevelopmental defects may be unmasked by a subsequent challenge. Adenosine and its receptors (AR) (A1, A2A, A2B and A3) which participate in the brain stres...

  11. Adenosine Signaling in Striatal Circuits and Alcohol Use Disorders

    Nam, Hyung Wook; Bruner, Robert C.; Choi, Doo-Sup

    2013-01-01

    Adenosine signaling has been implicated in the pathophysiology of alcohol use disorders and other psychiatric disorders such as anxiety and depression. Numerous studies have indicated a role for A1 receptors (A1R) in acute ethanol-induced motor incoordination, while A2A receptors (A2AR) mainly regulate the rewarding effect of ethanol in mice. Recent findings have demonstrated that dampened A2AR-mediated signaling in the dorsomedial striatum (DMS) promotes ethanol-seeking behaviors. Moreover, ...

  12. Myocardial energy metabolism in ischemic preconditioning, role of adenosine catabolism

    Kavianipour, Mohammad

    2002-01-01

    Brief episodes of ischemia and reperfusion render the myocardium more resistant to necrosis from a subsequent, otherwise lethal ischemic insult. This phenomenon is called ischemic preconditioning(IP). Today, much is known about the signalling pathways involved in IP; however, the details of the final steps leading to cardioprotection, remain elusive. Adenosine (a catabolite of ATP) plays a major role in the signalling pathways of IP. Following IP there is an unexplained discrepancy between an...

  13. Adenosine signaling in striatal circuits and alcohol use disorders.

    Nam, Hyung Wook; Bruner, Robert C; Choi, Doo-Sup

    2013-09-01

    Adenosine signaling has been implicated in the pathophysiology of alcohol use disorders and other psychiatric disorders such as anxiety and depression. Numerous studies have indicated a role for A1 receptors (A1R) in acute ethanol-induced motor incoordination, while A2A receptors (A2AR) mainly regulate the rewarding effect of ethanol in mice. Recent findings have demonstrated that dampened A2AR-mediated signaling in the dorsomedial striatum (DMS) promotes ethanol-seeking behaviors. Moreover, decreased A2AR function is associated with decreased CREB activity in the DMS, which enhances goal-oriented behaviors and contributes to excessive ethanol drinking in mice. Interestingly, caffeine, the most commonly used psychoactive substance, is known to inhibit both the A1R and A2AR. This dampened adenosine receptor function may mask some of the acute intoxicating effects of ethanol. Furthermore, based on the fact that A2AR activity plays a role in goal-directed behavior, caffeine may also promote ethanol-seeking behavior. The A2AR is enriched in the striatum and exclusively expressed in striatopallidal neurons, which may be responsible for the regulation of inhibitory behavioral control over drug rewarding processes through the indirect pathway of the basal ganglia circuit. Furthermore, the antagonistic interactions between adenosine and dopamine receptors in the striatum also play an integral role in alcoholism and addiction-related disorders. This review focuses on regulation of adenosine signaling in striatal circuits and the possible implication of caffeine in goal-directed behaviors and addiction. PMID:23912595

  14. Anxiolytic activity of adenosine receptor activation in mice.

    Jain, N; Kemp, N; Adeyemo, O; Buchanan, P; Stone, T W

    1995-10-01

    1. Purine analogues have been examined for anxiolytic- and anxiogenic-like activity in mice, by use of the elevated plus-maze. 2. The selective A1 receptor agonist, N6-cyclopentyladenosine (CPA) had marked anxiolytic-like activity at 10 and 50 microg kg(-1), with no effect on locomotor performance at these doses. 3. The A1 selective adenosine receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (CPX) had no significant effect on anxiety-related measures or locomotor behaviour, but blocked the anxiolytic-like activity of CPA. The hydrophilic xanthine, 8-(p-sulphophenyl) theophylline did not prevent anxiolysis by CPA. 4. Caffeine had anxiogenic-like activity at 30 mg kg(-1) which was prevented by CPA at 50 micro kg(-1). 5. The A2 receptor agonist, N6-[2-(3,5-dimethoxyphenyl)-2(2-methylphenyl)-ethyl]adenosine (DPMA) had no effect on anxiety behaviour but depressed locomotor activity at the highest dose tested of 1 mg kg(-1). The A2 receptor antagonist, 1,3-dimethyl-l-propargylxanthine (DMPX) had no effect on anxiety-related measures or locomotion and did not modify the anxiolytic-like activity of CPA. 6. Administration of DPMA in combination with anxiolytic doses of CPA prevented the anxiolytic-like activity of the latter. 7. The results suggest that the selective activation of central A1 adenosine receptors induces anxiolytic-like behaviour, while the activation of A2 sites causes locomotor depression and reduces the effects of A1 receptor activation. The absence of any effect of CPX alone suggests that the receptors involved in modulating behaviour in the elevated plus-maze in mice are not activated tonically by endogenous adenosine. PMID:8640355

  15. Intracellular signalling pathways in the vasoconstrictor response of mouse afferent arterioles to adenosine

    Hansen, Pernille B. Lærkegaard; Friis, Ulla Glenert; Uhrenholt, Torben Rene;

    2007-01-01

    calcium from the sarcoplasmic reticulum (SR), stimulated presumably by IP(3), is involved in the adenosine contraction mechanism of the afferent arteriole. In agreement with this notion is the observation that 2 aminoethoxydiphenyl borate (100 microM) blocked the adenosine-induced constriction whereas the...... protein kinase C inhibitor calphostin C had no effect. The calcium-activated chloride channel inhibitor IAA-94 (30 microM) inhibited the adenosine-mediated constriction. Patch clamp experiments showed that adenosine treatment induced a depolarizing current in preglomerular smooth muscle cells which was....... METHODS AND RESULTS: Adenosine (10(-7) M) significantly increased the intracellular calcium concentration in mouse isolated afferent arterioles measured by fura-2 fluorescence. Pre-treatment with thapsigargin (2 microM) blocked the vasoconstrictor action of adenosine (10(-7) M) indicating that release of...

  16. Adenosine A1 Receptor Antagonist Versus Montelukast on Airway Reactivity and Inflammation

    Nadeem, Ahmed; Obiefuna, Peter C.M.; Wilson, Constance N.; Mustafa, S. Jamal

    2006-01-01

    Adenosine produces bronchoconstriction in allergic rabbits, primates, and humans by activating adenosine A1 receptors. Previously, it is reported that a high dose of L-97-1, a water-soluble, small molecule adenosine A1 receptor antagonist, blocks early and late allergic responses, and bronchial hyper-responsiveness to histamine in a hyper-responsive rabbit model of allergic asthma. Effects of a lower dose of L-97-1 are compared to montelukast, a cysteinyl leukotriene-1 receptor antagonist on ...

  17. Traditional Acupuncture Triggers a Local Increase in Adenosine in Human Subjects

    Takano, Takahiro; Chen, Xiaolin; Luo, Fang; Fujita, Takumi; Ren, Zeguang; Goldman, Nanna; Zhao, Yuanli; Markman, John D.; Nedergaard, Maiken

    2012-01-01

    Acupuncture is a form of Eastern medicine that has been practiced for centuries. Despite its long history and worldwide application, the biological mechanisms of acupuncture in relieving pain have been poorly defined. Recent studies in mice, however, demonstrate that acupuncture triggers increases in interstitial adenosine, which reduces the severity of chronic pain through adenosine A1 receptors, suggesting that adenosine-mediated antinociception contributes to the clinical benefits of acupu...

  18. Respiratory stimulant effects of adenosine in man after caffeine and enprofylline.

    Smits, P; Schouten, J; Thien, T.

    1987-01-01

    In a double-blind and randomized study the respiratory stimulant effect of continuous intravenous adenosine infusion was studied after previous administration of caffeine, placebo and enprofylline in 10 healthy young volunteers. After placebo, adenosine induced an increase of minute ventilation (from 6.3 to 12.5 l min-1), tidal volume (from 0.60 to 0.96 l), and breathing rate (from 11.0 to 14.8 min-1). Venous pCO2 fell and pH rose after adenosine. Caffeine significantly reduced the adenosine-...

  19. Effects of adenosine and adenosine A2A receptor agonist on motor nerve conduction velocity and nerve blood flow in experimental diabetic neuropathy.

    Kumar, Sokindra; Arun, K H S; Kaul, Chaman L; Sharma, Shyam S

    2005-01-01

    This study examined the effects of chronic administration of adenosine and CGS 21680 hydrochloride (adenosine A(2A) receptor agonist) on motor nerve conduction velocity (MNCV), nerve blood flow (NBF) and histology of sciatic nerve in animal model of diabetic neuropathy. Adenosinergic agents were administered for 2 weeks after 6 weeks of streptozotocin-induced (50 mg/kg i.p.) diabetes in male Sprague-Dawley rats. Significant reduction in sciatic MNCV and NBF were observed after 8 weeks in diabetic animals in comparison with control (non diabetic) rats. Adenosine (10 mg/kg, i.p.) significantly improved sciatic MNCV and NBF in diabetic rats. The protective effect of adenosine on MNCV and NBF was completely reversed by theophylline (50 mg/kg, i.p.), a non-selective adenosine receptor antagonist, suggesting that the adenosine effect was mediated via adenosinergic receptors. CGS 21680 (0.1 mg/kg, i.p.) significantly improved NBF; however, MNCV was not significantly improved in diabetic rats. At a dose of 1 mg/kg, neither MNCV nor NBF was improved by CGS 21680 in diabetic rats. ZM 241385 (adenosine A(2A) receptor antagonist) prevented the effect of CGS 21680 (0.1 mg/kg, i.p.). Histological changes observed in sciatic nerve were partially improved by the adenosinergic agents in diabetic rats. Results of the present study, suggest the potential of adenosinergic agents in the therapy of diabetic neuropathy. PMID:15829161

  20. Characterization of spontaneous, transient adenosine release in the caudate-putamen and prefrontal cortex.

    Michael D Nguyen

    Full Text Available Adenosine is a neuroprotective agent that inhibits neuronal activity and modulates neurotransmission. Previous research has shown adenosine gradually accumulates during pathologies such as stroke and regulates neurotransmission on the minute-to-hour time scale. Our lab developed a method using carbon-fiber microelectrodes to directly measure adenosine changes on a sub-second time scale with fast-scan cyclic voltammetry (FSCV. Recently, adenosine release lasting a couple of seconds has been found in murine spinal cord slices. In this study, we characterized spontaneous, transient adenosine release in vivo, in the caudate-putamen and prefrontal cortex of anesthetized rats. The average concentration of adenosine release was 0.17±0.01 µM in the caudate and 0.19±0.01 µM in the prefrontal cortex, although the range was large, from 0.04 to 3.2 µM. The average duration of spontaneous adenosine release was 2.9±0.1 seconds and 2.8±0.1 seconds in the caudate and prefrontal cortex, respectively. The concentration and number of transients detected do not change over a four hour period, suggesting spontaneous events are not caused by electrode implantation. The frequency of adenosine transients was higher in the prefrontal cortex than the caudate-putamen and was modulated by A1 receptors. The A1 antagonist DPCPX (8-cyclopentyl-1,3-dipropylxanthine, 6 mg/kg i.p. increased the frequency of spontaneous adenosine release, while the A1 agonist CPA (N(6-cyclopentyladenosine, 1 mg/kg i.p. decreased the frequency. These findings are a paradigm shift for understanding the time course of adenosine signaling, demonstrating that there is a rapid mode of adenosine signaling that could cause transient, local neuromodulation.

  1. Is adenosine a modulator of peripheral vasoconstrictor responses?

    Dayan, Lior; Brill, Silviu; Hochberg, Uri; Jacob, Giris

    2016-01-01

    Background Local vasoconstrictor reflexes, the vascular myogenic response (VMR) and the veno-arterial reflex (VAR) are necessary for the maintenance of regional blood flow and systemic arterial blood pressure during orthostatic stress. Their molecular mechanism is unknown. We postulated that adenosine is involved in the activation of these local reflexes. Methods This hypothesis was tested in 10 healthy male volunteers (age 29 ± 3 years, BMI 24 ± 1 kg/m2). We used veno-occlusive plethysmograp...

  2. Differential response of Drosophila cell lines to extracellular adenosine

    Fleischmannová, J.; Kučerová, Lucie; Šandová, Kateřina; Steinbauerová, Veronika; Brož, Václav; Šimek, Petr; Žurovec, Michal

    2012-01-01

    Roč. 42, č. 5 (2012), s. 321-331. ISSN 0965-1748 R&D Projects: GA MŠk(CZ) LC06077 Grant ostatní: AV ČR(CZ) KJB501410801; European Community´s Seventh Framwork Programme (FP7/2007-2013)(CZ) 229518 Institutional research plan: CEZ:AV0Z50070508 Institutional support: RVO:60077344 Keywords : adenosine recycling * nucleoside transport * Mbn2 Subject RIV: CE - Biochemistry Impact factor: 3.234, year: 2012 http://www.sciencedirect.com/science/article/pii/S0965174812000033

  3. Anxiolytic activity of adenosine receptor activation in mice.

    Jain, N; Kemp, N; Adeyemo, O; Buchanan, P.; Stone, T W

    1995-01-01

    1. Purine analogues have been examined for anxiolytic- and anxiogenic-like activity in mice, by use of the elevated plus-maze. 2. The selective A1 receptor agonist, N6-cyclopentyladenosine (CPA) had marked anxiolytic-like activity at 10 and 50 microg kg(-1), with no effect on locomotor performance at these doses. 3. The A1 selective adenosine receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (CPX) had no significant effect on anxiety-related measures or locomotor behaviour, but blocked ...

  4. Stimulation of adenosine receptors: approach to enhancement of hematopoiesis suppressed by chemoradiotherapy

    Elevated extracellular adenosine has been found to stimulate hematopoiesis in experimental mice exposed to radiotherapy (gamma-rays), chemotherapy (5-fluorouracil), or combined action of both these modalities (gamma-rays + carboplatin). These findings have been obtained after treatment of the animals with the combination of dipyridamole (DP), preventing the cellular uptake of adenosine, and adenosine monophosphate (AMP), acting as adenosine prodrug. Increased cycling of hematopoietic progenitor cells following the administration of DP + AMP has been shown to represent an important mechanism of acceleration of regeneration of suppressed hematopoiesis. In recent experiments, non-degradable synthetic adenosine receptor agonists, more or less specific for individual subtypes of adenosine receptors (A1, A2A, A2B, and A3 subtypes) have been studied. These studies have included 5'-(N-ethylcarboxamido)adenosine (NECA, rather non-selective agonist with relatively high affinity to A2B receptor subtype), N6-cyclopentyladenosine (CPA, agonist specific for A1 receptor subtype), 2-p-(carboxyethyl)phene thylamino-5'-N-ethylcarboxamidoadenosine (CGS 21680, agonist specific for A2A receptor subtype), and 1-deoxy-1-([((3- iodophenyl)methyl)-amino]-9H-purin-9-yl)-N-methyl-beta-D-ribofuranoamide (IB-MECA, agonist specific for A3 receptor subtype). Results from these studies have stressed the potential significance of stimulation of various adenosine receptor subtypes for modulation of functional status of hematopoietic progenitor cells. These findings may find important practical implications in the treatment of side effects of chemoradiotherapy

  5. Role of adenosine in the sympathetic activation produced by isometric exercise in humans.

    Costa, F.; Biaggioni, I

    1994-01-01

    Isometric exercise increases sympathetic nerve activity and blood pressure. This exercise pressor reflex is partly mediated by metabolic products activating muscle afferents (metaboreceptors). Whereas adenosine is a known inhibitory neuromodulator, there is increasing evidence that it activates afferent nerves. We, therefore, examined the hypothesis that adenosine stimulates muscle afferents and participates in the exercise pressor reflex in healthy volunteers. Intraarterial administration of...

  6. Lack of adenosine A(3) receptors causes defects in mouse peripheral blood parameters

    Hofer, Michal; Pospíšil, Milan; Dušek, L.; Hoferová, Zuzana; Komůrková, Denisa

    2014-01-01

    Roč. 10, č. 3 (2014), s. 509-514. ISSN 1573-9538 R&D Projects: GA ČR(CZ) GAP303/11/0128 Institutional support: RVO:68081707 Keywords : Adenosine A(3) receptor * Adenosine A(3) receptor knockout mice * Hematopoiesis Subject RIV: BO - Biophysics Impact factor: 3.886, year: 2014

  7. Comparison of exogenous adenosine and voluntary exercise on human skeletal muscle perfusion and perfusion heterogeneity

    Heinonen, Ilkka H.A.; Kemppainen, Jukka; Kaskinoro, Kimmo;

    2010-01-01

    Adenosine is a widely used pharmacological agent to induce a 'high flow' control condition to study the mechanisms of exercise hyperemia, but it is not known how well adenosine infusion depicts exercise-induced hyperemia especially in terms of blood flow distribution at the capillary level in hum...

  8. Role of adenosine in regulating the heterogeneity of skeletal muscle blood flow during exercise in humans

    Heinonen, Ilkka; Nesterov, Sergey V; Kemppainen, Jukka;

    2007-01-01

    Evidence from both animal and human studies suggests that adenosine plays a role in the regulation of exercise hyperemia in skeletal muscle. We tested whether adenosine also plays a role in the regulation of blood flow (BF) distribution and heterogeneity among and within quadriceps femoris (QF...

  9. Feed-Forward Inhibition of CD73 and Upregulation of Adenosine Deaminase Contribute to the Loss of Adenosine Neuromodulation in Postinflammatory Ileitis

    Cátia Vieira; Maria Teresa Magalhães-Cardoso; Fátima Ferreirinha; Isabel Silva; Ana Sofia Dias; Julie Pelletier; Jean Sévigny; Paulo Correia-de-Sá

    2014-01-01

    Purinergic signalling is remarkably plastic during gastrointestinal inflammation. Thus, selective drugs targeting the “purinome” may be helpful for inflammatory gastrointestinal diseases. The myenteric neuromuscular transmission of healthy individuals is fine-tuned and controlled by adenosine acting on A2A excitatory receptors. Here, we investigated the neuromodulatory role of adenosine in TNBS-inflamed longitudinal muscle-myenteric plexus of the rat ileum. Seven-day postinflammation ileitis ...

  10. Adenosine Amine Congener as a Cochlear Rescue Agent

    Srdjan M. Vlajkovic

    2014-01-01

    Full Text Available We have previously shown that adenosine amine congener (ADAC, a selective A1 adenosine receptor agonist, can ameliorate noise- and cisplatin-induced cochlear injury. Here we demonstrate the dose-dependent rescue effects of ADAC on noise-induced cochlear injury in a rat model and establish the time window for treatment. Methods. ADAC (25–300 μg/kg was administered intraperitoneally to Wistar rats (8–10 weeks old at intervals (6–72 hours after exposure to traumatic noise (8–16 kHz, 110 dB sound pressure level, 2 hours. Hearing sensitivity was assessed using auditory brainstem responses (ABR before and 12 days after noise exposure. Pharmacokinetic studies investigated ADAC concentrations in plasma after systemic (intravenous administration. Results. ADAC was most effective in the first 24 hours after noise exposure at doses >50 μg/kg, providing up to 21 dB protection (averaged across 8–28 kHz. Pharmacokinetic studies demonstrated a short (5 min half-life of ADAC in plasma after intravenous administration without detection of degradation products. Conclusion. Our data show that ADAC mitigates noise-induced hearing loss in a dose- and time-dependent manner, but further studies are required to establish its translation as a clinical otological treatment.

  11. Adenosine signaling and the energetic costs of induced immunity.

    Lazzaro, Brian P

    2015-04-01

    Life history theory predicts that trait evolution should be constrained by competing physiological demands on an organism. Immune defense provides a classic example in which immune responses are presumed to be costly and therefore come at the expense of other traits related to fitness. One strategy for mitigating the costs of expensive traits is to render them inducible, such that the cost is paid only when the trait is utilized. In the current issue of PLOS Biology, Bajgar and colleagues elegantly demonstrate the energetic and life history cost of the immune response that Drosophila melanogaster larvae induce after infection by the parasitoid wasp Leptopilina boulardi. These authors show that infection-induced proliferation of defensive blood cells commands a diversion of dietary carbon away from somatic growth and development, with simple sugars instead being shunted to the hematopoetic organ for rapid conversion into the raw energy required for cell proliferation. This metabolic shift results in a 15% delay in the development of the infected larva and is mediated by adenosine signaling between the hematopoietic organ and the central metabolic control organ of the host fly. The adenosine signal thus allows D. melanogaster to rapidly marshal the energy needed for effective defense and to pay the cost of immunity only when infected. PMID:25915419

  12. Adenosine signaling and the energetic costs of induced immunity.

    Brian P Lazzaro

    2015-04-01

    Full Text Available Life history theory predicts that trait evolution should be constrained by competing physiological demands on an organism. Immune defense provides a classic example in which immune responses are presumed to be costly and therefore come at the expense of other traits related to fitness. One strategy for mitigating the costs of expensive traits is to render them inducible, such that the cost is paid only when the trait is utilized. In the current issue of PLOS Biology, Bajgar and colleagues elegantly demonstrate the energetic and life history cost of the immune response that Drosophila melanogaster larvae induce after infection by the parasitoid wasp Leptopilina boulardi. These authors show that infection-induced proliferation of defensive blood cells commands a diversion of dietary carbon away from somatic growth and development, with simple sugars instead being shunted to the hematopoetic organ for rapid conversion into the raw energy required for cell proliferation. This metabolic shift results in a 15% delay in the development of the infected larva and is mediated by adenosine signaling between the hematopoietic organ and the central metabolic control organ of the host fly. The adenosine signal thus allows D. melanogaster to rapidly marshal the energy needed for effective defense and to pay the cost of immunity only when infected.

  13. Distribution of adenosine receptors in human sclera fibroblasts

    Cui, Dongmei; Trier, Klaus; Chen, Xiang; Zeng, Junwen; Yang, Xiao; Hu, Jianmin

    2008-01-01

    Purpose Systemic treatment with adenosine receptor antagonists has been reported to affect the biochemistry and ultrastructure of rabbit sclera. This study was conducted to determine whether adenosine receptors (ADORs) are present in human scleral fibroblasts (HSF). Methods Primary HSF were cultured in vitro and identified with anti-vimentin, anti-keratin, anti-desmin, and anti-S-100 antibodies. Confocal fluorescence microscopy was used to study the distribution of ADORs in the HSF cell lines and in the frozen human scleral sections. ADOR protein expression in HSF and human sclera was confirmed by western blot analysis of cell lysates. Results ADORs were expressed in both HSF and human sclera. This was confirmed by western blot. ADORA1 expression was concentrated in the nucleus. ADORA2A was concentrated mainly in one side of the cytoplasm, and ADORA2B was found both in the nucleus and the cytoplasm. ADORA3 was expressed weakly in the cytoplasm. Conclusions All four subtypes of ADOR were found in HSF and may play a role in scleral remodeling. PMID:18385786

  14. Cloning, expression and pharmacological characterization of rabbit adenosine A1 and A3 receptors.

    Hill, R J; Oleynek, J J; Hoth, C F; Kiron, M A; Weng, W; Wester, R T; Tracey, W R; Knight, D R; Buchholz, R A; Kennedy, S P

    1997-01-01

    The role of adenosine A1 and A3 receptors in mediating cardioprotection has been studied predominantly in rabbits, yet the pharmacological characteristics of rabbit adenosine A1 and A3 receptor subtypes are unknown. Thus, the rabbit adenosine A3 receptor was cloned and expressed, and its pharmacology was compared with that of cloned adenosine A1 receptors. Stable transfection of rabbit A1 or A3 cDNAs in Chinese hamster ovary-K1 cells resulted in high levels of expression of each of the receptors, as demonstrated by high-affinity binding of the A1/A3 adenosine receptor agonist N6-(4-amino-3-[125I]iodobenzyl)adenosine (125I-ABA). For both receptors, binding of 125I-ABA was inhibited by the GTP analog 5'-guanylimidodiphosphate, and forskolin-stimulated cyclic AMP accumulation was inhibited by the adenosine receptor agonist (R)-phenylisopropyladenosine. The rank orders of potency of adenosine receptor agonists for inhibition of 125I-ABA binding were as follows: rabbit A1, N6-cyclopentyladenosine = (R)-phenylisopropyladenosine > N-ethylcarboxamidoadenosine > or = I-ABA > or = N6-2-(4-aminophenyl) ethyladenosine > > N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide > N6-(4-amino-3-benzyl)adenosine; rabbit A3, N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide > or = I-ABA > > N-ethylcarboxamidoadenosine > N6-2-(4-aminophenyl) ethyladenosine = N6-cyclopentyladenosine = (R)-phenylisopropyladenosine > N6-(4-amino-3-benzyl)adenosine. The adenosine receptor antagonist rank orders were as follow: rabbit A1, 8-cyclopentyl-1,3-dipropylxanthine > 1,3- dipropyl-8-(4-acrylate)phenylxanthine > or = xanthine amine congener > > 8-(p-sulfophenyl)theophylline; rabbit A3, xanthine amine congener > 1,3-dipropyl-8-(4-acrylate)phenylxanthine > or = 8-cyclopentyl-1,3-dipropylxanthine > > 8-(p-sulfophenyl)theophylline. These observations confirm the identity of the expressed proteins as A1 and A3 receptors. The results will facilitate further in-depth studies of the roles of A1 and A3 receptors in

  15. Quantitative analysis of adenosine using Liquid Chromatography/Atmospheric Pressure Chemical Ionization - tandem Mass Spectrometry (LC/APCI-MS/MS)

    Van Dycke, Annelies; Verstraete, Alain; Pil, Kristof; Raedt, Robrecht; Vonck, Kristl; Boison, Detlev; Boon, Paul

    2010-01-01

    Adenosine-secreting cellular brain implants constitute a promising therapeutic approach for the treatment of epilepsy. To engineer neural stem cells for therapeutic adenosine delivery, a reliable and fast analytical method is necessary to quantify cell-based adenosine release. Here we describe the development, optimization and validation of adenosine measurement using liquid chromatography – atmospheric pressure chemical ionization – tandem mass spectrometry (LC-APCI-MS/MS). LC-MS/MS in posit...

  16. Distinct Roles for the A2B Adenosine Receptor in Acute and Chronic Stages of Bleomycin-Induced Lung Injury

    Yang ZHOU; Schneider, Daniel J.; Morschl, Eva; Song, Ling; Pedroza, Mesias; Karmouty-Quintana, Harry; Le, Thuy.; Sun, Chun-Xiao; Blackburn, Michael R.

    2010-01-01

    Adenosine is an extracellular signaling molecule that is generated in response to cell injury where it orchestrates tissue protection and repair. Whereas adenosine is best known for promoting anti-inflammatory activities during acute injury responses, prolonged elevations can enhance destructive tissue remodeling processes associated with chronic disease states. The generation of adenosine and the subsequent activation of the adenosine 2B receptor (A2BR) is an important processes in the regul...

  17. Interaction of porphyrins with adenine and adenosine complexes. Effect of a metal nature

    Reactions of complex formation of 5,10,15,20-tetraphenylporphine (H2TPP) and tetra-tert-butylphthalocyanine (H2(t-Bu)4Pc) with adenine and adenosine complexes of d-metals (M=Cd, Co, Cu, Hg, Zn) in DMSO and ethanol are studied. It was found that H2TPP reacts with Cu(II) and Hg(II) adeninates and adenosinates in DMSO, but does not react with Zn(II), Co(II), and Cd(II) adeninates and adenosinates (with both bridging and monodentate type of the ligand coordination). H2(t-Bu)4Pc enters the complex formation reaction with adeninates and adenosinates of all studied metals in DMSO at almost equal rates. The states of adenine and adenosine complexes of different d-metals in DMSO and ethanol are proposed on the basis of kinetic data obtained

  18. Adenosine stimulates DNA fragmentation in human thymocytes by Ca(2+)-mediated mechanisms.

    Szondy, Z

    1994-12-15

    Incubation of human thymocytes with an optimum concentration of adenosine and its receptor site agonist, 2-chloroadenosine, induced increases in intracellular cyclic AMP (cAMP) (from a resting 0.6 +/- 0.1 to 4.1 +/- 0.2 pmol/10(7) cells within 5 min) and Ca2+ (from the resting 85 +/- 7 nM to a peak of 210 +/- 25 nM) levels and resulted in internucleosomal DNA fragmentation and cell death (apoptosis). Other adenosine analogues were also effective at inducing DNA fragmentation, the order of potency being 2-p-(carboxyethylphenylethylamino)-5'-carboxyamidoadenosine 13399-13402], at 60 ng/ml concentration also prevented adenosine-induced DNA fragmentation when added prior to adenosine. This suggested a complex cross-talk between the adenosine-triggered signal transduction cascade and the activation state of protein kinase C in regulating apoptosis of human thymocytes. PMID:7818494

  19. 2-(1-Hexyn-1-yl)adenosine-induced intraocular hypertension is mediated via K+ channel opening through adenosine A2A receptor in rabbits.

    Konno, Takashi; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2005-08-22

    The present study was performed to clarify the mechanism of change in intraocular pressure by 2-(1-hexyn-1-yl)adenosine (2-H-Ado), a selective adenosine A2 receptor agonist, in rabbits. 2-H-Ado (0.1%, 50 microl)-induced ocular hypertension (E(max): 7.7 mm Hg) was inhibited by an adenosine A2A receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine, ATP-sensitive K+ channel blocker glibenclamide or 5-hydroxydecanoic acid, but not by an adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine, an adenosine A2B receptor antagonist alloxazine or a cyclooxygenase inhibitor indomethacin. The outflow facility induced by 2-H-Ado seems to be independent of increase in intraocular pressure or ATP-sensitive K+ channel. In contrast, the recovery rate in intraocular pressure decreased by hypertonic saline was accelerated by 2-H-Ado, and this response was dependent on ATP-sensitive K+ channel. These results suggest that 2-H-Ado-induced ocular hypertension is mediated via K+ channel opening through adenosine A2A receptor, and this is probably due to aqueous formation, but independent of change in outflow facility or prostaglandin production. PMID:16023100

  20. Autophagy occurs within an hour of adenosine triphosphate treatment after nerve cell damage:the neuroprotective effects of adenosine triphosphate against apoptosis

    Na Lu; Baoying Wang; Xiaohui Deng; Honggang Zhao; Yong Wang; Dongliang Li

    2014-01-01

    After hypoxia, ischemia, or inlfammatory injuries to the central nervous system, the damaged cells release a large amount of adenosine triphosphate, which may cause secondary neuronal death. Autophagy is a form of cell death that also has neuroprotective effects. Cell Counting Kit assay, monodansylcadaverine staining, lfow cytometry, western blotting, and real-time PCR were used to determine the effects of exogenous adenosine triphosphate treatment at different concentrations (2, 4, 6, 8, 10 mmol/L) over time (1, 2, 3, and 6 hours) on the apoptosis and autophagy of SH-SY5Y cells. High concentrations of extracellular adenosine triphosphate induced autophagy and apoptosis of SH-SY5Y cells. The enhanced autophagy ifrst appeared, and peaked at 1 hour after treatment with adenosine triphosphate. Cell apoptosis peaked at 3 hours, and persisted through 6 hours. With prolonged exposure to the adenosine triphosphate treatment, the fraction of apoptotic cells increased. These data suggest that the SH-SY5Y neural cells initiated autophagy against apoptosis within an hour of adenosine triphosphate treatment to protect themselves against injury.

  1. Involvement of adenosine A2a receptor in intraocular pressure decrease induced by 2-(1-octyn-1-yl)adenosine or 2-(6-cyano-1-hexyn-1-yl)adenosine.

    Konno, Takashi; Murakami, Akira; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2005-04-01

    The aim of the present study is to clarify the mechanism for the decrease in intraocular pressure by 2-alkynyladenosine derivatives in rabbits. The receptor binding analysis revealed that 2-(1-octyn-1-yl)adenosine (2-O-Ado) and 2-(6-cyano-1-hexyn-1-yl)adenosine (2-CN-Ado) selectively bound to the A(2a) receptor with a high affinity. Ocular hypotensive responses to 2-O-Ado and 2-CN-Ado were inhibited by the adenosine A(2a)-receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine (CSC), but not by the adenosine A(1)-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) or the adenosine A(2b)-receptor antagonist alloxazine. In addition, 2-O-Ado and 2-CN-Ado caused an increase in outflow facility, which was inhibited by CSC, but not by DPCPX or alloxazine. Moreover, 2-O-Ado and 2-CN-Ado increased cAMP in the aqueous humor, and the 2-O-Ado-induced an increase in cAMP was inhibited by CSC. These results suggest that 2-O-Ado and 2-CN-Ado reduced intraocular pressure via an increase in outflow facility. The ocular hypotension may be mainly mediated through the activation of adenosine A(2a) receptor, although a possible involvement of adenosine A(1) receptor cannot be completely ruled out. 2-O-Ado and 2-CN-Ado are useful lead compounds for the treatment of glaucoma. PMID:15821340

  2. Real-time monitoring of extracellular adenosine using enzyme-linked microelectrode arrays.

    Hinzman, Jason M; Gibson, Justin L; Tackla, Ryan D; Costello, Mark S; Burmeister, Jason J; Quintero, Jorge E; Gerhardt, Greg A; Hartings, Jed A

    2015-12-15

    Throughout the central nervous system extracellular adenosine serves important neuroprotective and neuromodulatory functions. However, current understanding of the in vivo regulation and effects of adenosine is limited by the spatial and temporal resolution of available measurement techniques. Here, we describe an enzyme-linked microelectrode array (MEA) with high spatial (7500 µm(2)) and temporal (4 Hz) resolution that can selectively measure extracellular adenosine through the use of self-referenced coating scheme that accounts for interfering substances and the enzymatic breakdown products of adenosine. In vitro, the MEAs selectively measured adenosine in a linear fashion (r(2)=0.98±0.01, concentration range=0-15 µM, limit of detection =0.96±0.5 µM). In vivo the limit of detection was 0.04±0.02 µM, which permitted real-time monitoring of the basal extracellular concentration in rat cerebral cortex (4.3±1.5 µM). Local cortical injection of adenosine through a micropipette produced dose-dependent transient increases in the measured extracellular concentration (200 nL: 6.8±1.8 µM; 400 nL: 19.4±5.3 µM) [P<0.001]. Lastly, local injection of dipyridamole, which inhibits transport of adenosine through equilibrative nucleoside transporter, raised the measured extracellular concentration of adenosine by 120% (5.6→12.3 µM) [P<0.001]. These studies demonstrate that MEAs can selectively measure adenosine on temporal and spatial scales relevant to adenosine signaling and regulation in normal and pathologic states. PMID:26183072

  3. Specificity of synergistic coronary flow enhancement by adenosine and pulsatile perfusion in the dog.

    Pagliaro, P; Senzaki, H; Paolocci, N; Isoda, T; Sunagawa, G; Recchia, F A; Kass, D A

    1999-10-01

    1. Coronary flow elevation from enhanced perfusion pulsatility is synergistically amplified by adenosine. This study determined the specificity of this interaction and its potential mechanisms. 2. Mean and phasic coronary flow responses to increasing pulsatile perfusion were assessed in anaesthetized dogs, with the anterior descending coronary artery servoperfused to regulate real-time physiological flow pulsatility at constant mean pressure. Pulsatility was varied between 40 and 100 mmHg. Hearts ejected into the native aorta whilst maintaining stable loading. 3. Increasing pulsatility elevated mean coronary flow +11.5 +/- 1.7 % under basal conditions. Co-infusion of adenosine sufficient to raise baseline flow 66 % markedly amplified this pulsatile perfusion response (+82. 6 +/- 14.3 % increase in mean flow above adenosine baseline), due to a leftward shift of the adenosine-coronary flow response curve at higher pulsatility. Flow augmentation with pulsatility was not linked to higher regional oxygen consumption, supporting direct rather than metabolically driven mechanisms. 4. Neither bradykinin, acetylcholine nor verapamil reproduced the synergistic amplification of mean flow by adenosine and higher pulsatility, despite being administered at doses matching basal flow change with adenosine. 5. ATP-sensitive potassium (KATP) activation (pinacidil) amplified the pulse-flow response 3-fold, although this remained significantly less than with adenosine. Co-administration of the phospholipase A2 inhibitor quinacrine virtually eliminated adenosine-induced vasodilatation, yet synergistic interaction between adenosine and pulse perfusion persisted, albeit at a reduced level. 6. Thus, adenosine and perfusion pulsatility specifically interact to enhance coronary flow. This synergy is partially explained by KATP agonist action and additional non-flow-dependent mechanisms, and may be important for modulating flow reserve during exercise or other high output states where

  4. Overexpression, purification and crystallographic analysis of a unique adenosine kinase from Mycobacterium tuberculosis

    Adenosine kinase from M. tuberculosis has been overexpressed, purified and crystallized in the presence of adenosine. Structure determination using molecular replacement with diffraction data collected at 2.2 Å reveals a dimeric structure. Adenosine kinase from Mycobacterium tuberculosis is the only prokaryotic adenosine kinase that has been isolated and characterized. The enzyme catalyzes the phosphorylation of adenosine to adenosine monophosphate and is involved in the activation of 2-methyladenosine, a compound that has demonstrated selective activity against M. tuberculosis. The mechanism of action of 2-methyladenosine is likely to be different from those of current tuberculosis treatments and this compound (or other adenosine analogs) may prove to be a novel therapeutic intervention for this disease. The M. tuberculosis adenosine kinase was overexpressed in Escherichia coli and the enzyme was purified with activity comparable to that reported previously. The protein was crystallized in the presence of adenosine using the vapour-diffusion method. The crystals diffracted X-rays to high resolution and a complete data set was collected to 2.2 Å using synchrotron radiation. The crystal belonged to space group P3121, with unit-cell parameters a = 70.2, c = 111.6 Å, and contained a single protein molecule in the asymmetric unit. An initial structural model of the protein was obtained by the molecular-replacement method, which revealed a dimeric structure. The monomers of the dimer were related by twofold crystallographic symmetry. An understanding of how the M. tuberculosis adenosine kinase differs from the human homolog should aid in the design of more potent and selective antimycobacterial agents that are selectively activated by this enzyme

  5. Online cleanup of accelerated solvent extractions for determination of adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), and adenosine 5'-monophosphate (AMP) in royal jelly using high-performance liquid chromatography.

    Xue, Xiaofeng; Wang, Feng; Zhou, Jinhui; Chen, Fang; Li, Yi; Zhao, Jing

    2009-06-10

    Determination of the levels of adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), and adenosine 5'-monophosphate (AMP) in royal jelly is important for the study of its pharmacological activities, health benefits, and adenosine phosphate degradation. In this study was developed a novel method to determine ATP, ADP, and AMP levels in royal jelly using accelerated solvent extraction (ASE) followed by online cleanup and high-performance liquid chromatography (HPLC) with diode array detection (DAD). The optimum extraction conditions were obtained using an 11 mL ASE cell, ethanol/water (5:5 v/v) as the extraction solvent, 1500 psi, 80 degrees C, a 5 min static time, and a 60% flush volume. Optimum separation of the three compounds was achieved in extraction procedures developed here were compared with the classical adenosine phosphate extraction procedures (perchloric acid). The results indicate that the two techniques are similar in terms of recovery and reproducibility, but when other factors such as extraction time, environmental protection, and worker's health are considered, ASE is preferable to the classical extraction method. With this ASE-HPLC method, a minisurvey of ATP, ADP, and AMP levels in 15 samples of royal jelly of different origins was performed. Sample results indicated that the AMP concentration was 24.2-2214.4 mg kg(-1), whereas ATP and ADP were not detectable or present only at low levels. PMID:19435312

  6. The Role of Adenosine in Pulmonary Vein Isolation: A Critical Review

    Dallaglio, Paolo D.; Betts, Timothy R.; Ginks, Matthew; Bashir, Yaver; Anguera, Ignasi; Rajappan, Kim

    2016-01-01

    The cornerstone of atrial fibrillation (AF) ablation is pulmonary vein isolation (PVI), which can be achieved in more than 95% of patients at the end of the procedure. However, AF recurrence rates remain high and are related to recovery of PV conduction. Adenosine testing is used to unmask dormant pulmonary vein conduction (DC). The aim of this study is to review the available literature addressing the role of adenosine testing and determine the impact of ablation at sites of PV reconnection on freedom from AF. Adenosine infusion, by restoring the excitability threshold, unmasks reversible injury that could lead to recovery of PV conduction. The studies included in this review suggest that adenosine is useful to unmask nontransmural lesions at risk of reconnection and that further ablation at sites of DC is associated with improvement in freedom from AF. Nevertheless it has been demonstrated that adenosine is not able to predict all veins at risk of later reconnection, which means that veins without DC are not necessarily at low risk. The role of the waiting period in the setting of adenosine testing has also been analyzed, suggesting that in the acute phase adenosine use should be accompanied by enough waiting time. PMID:26981309

  7. Susceptibility to seizure-induced sudden death in DBA/2 mice is altered by adenosine.

    Faingold, Carl L; Randall, Marc; Kommajosyula, Srinivasa P

    2016-08-01

    Sudden unexpected death in epilepsy (SUDEP) is rare but is an important public health burden due to the number of patient years lost. Respiratory dysfunction following generalized convulsive seizure is a common sequence of events in witnessed SUDEP cases. The DBA/2 mouse model of SUDEP exhibits generalized convulsive audiogenic seizures (AGSz), which result in seizure-induced respiratory arrest (S-IRA) in ∼75% of these animals, while the remaining DBA/2 mice exhibit AGSz without S-IRA. SUDEP induction may involve actions of adenosine, which is released during generalized seizures in animals and patients and is known to depress respiration. This study examined the effects of systemic administration of agents that alter the actions of adenosine on the incidence of S-IRA in DBA/2 mice. DBA/2 mice that consistently exhibited AGSz without S-IRA showed a significantly increased incidence of S-IRA following treatment with 5-iodotubercidin, which blocks adenosine metabolism. Treatment of DBA/2 mice that consistently exhibited AGSz followed by S-IRA with a non-selective adenosine antagonist, caffeine, or an A2A adenosine receptor subtype-selective antagonist (SCH 442416) significantly reduced S-IRA incidence. By contrast, an A1 adenosine receptor antagonist (DPCPX) was not effective in reducing S-IRA incidence. These findings suggest that preventative approaches for SUDEP should consider agents that reduce the actions of adenosine. PMID:27259068

  8. Role of adenosine signalling and metabolism in β-cell regeneration

    Andersson, Olov, E-mail: olov.andersson@ki.se

    2014-02-01

    Glucose homeostasis, which is controlled by the endocrine cells of the pancreas, is disrupted in both type I and type II diabetes. Deficiency in the number of insulin-producing β cells – a primary cause of type I diabetes and a secondary contributor of type II diabetes – leads to hyperglycemia and hence an increase in the need for insulin. Although diabetes can be controlled with insulin injections, a curative approach is needed. A potential approach to curing diabetes involves regenerating the β-cell mass, e.g. by increasing β-cell proliferation, survival, neogenesis or transdifferentiation. The nucleoside adenosine and its cognate nucleotide ATP have long been known to affect insulin secretion, but have more recently been shown to increase β-cell proliferation during homeostatic control and regeneration of the β-cell mass. Adenosine is also known to have anti-inflammatory properties, and agonism of adenosine receptors can promote the survival of β-cells in an inflammatory microenvironment. In this review, both intracellular and extracellular mechanisms of adenosine and ATP are discussed in terms of their established and putative effects on β-cell regeneration. - Highlights: • A potential way to cure diabetes is to regenerate the β-cell mass by promoting cell survival, proliferation or neogenesis. • Adenosine may promote β-cell regeneration through several cellular mechanisms. • Adenosine and its cognate nucleotide ATP can each promote β-cell proliferation. • Do adenosine and ATP interact in promoting β-cell proliferation?.

  9. Adenosine, ketogenic diet and epilepsy: the emerging therapeutic relationship between metabolism and brain activity.

    Masino, S A; Kawamura, M; Wasser, C D; Wasser, C A; Pomeroy, L T; Ruskin, D N

    2009-09-01

    For many years the neuromodulator adenosine has been recognized as an endogenous anticonvulsant molecule and termed a "retaliatory metabolite." As the core molecule of ATP, adenosine forms a unique link between cell energy and neuronal excitability. In parallel, a ketogenic (high-fat, low-carbohydrate) diet is a metabolic therapy that influences neuronal activity significantly, and ketogenic diets have been used successfully to treat medically-refractory epilepsy, particularly in children, for decades. To date the key neural mechanisms underlying the success of dietary therapy are unclear, hindering development of analogous pharmacological solutions. Similarly, adenosine receptor-based therapies for epilepsy and myriad other disorders remain elusive. In this review we explore the physiological regulation of adenosine as an anticonvulsant strategy and suggest a critical role for adenosine in the success of ketogenic diet therapy for epilepsy. While the current focus is on the regulation of adenosine, ketogenic metabolism and epilepsy, the therapeutic implications extend to acute and chronic neurological disorders as diverse as brain injury, inflammatory and neuropathic pain, autism and hyperdopaminergic disorders. Emerging evidence for broad clinical relevance of the metabolic regulation of adenosine will be discussed. PMID:20190967

  10. Cancer exosomes express CD39 and CD73, which suppress T cells through adenosine production.

    Clayton, Aled; Al-Taei, Saly; Webber, Jason; Mason, Malcolm D; Tabi, Zsuzsanna

    2011-07-15

    Extracellular adenosine is elevated in cancer tissue, and it negatively regulates local immune responses. Adenosine production from extracellular ATP has attracted attention as a mechanism of regulatory T cell-mediated immune regulation. In this study, we examined whether small vesicles secreted by cancer cells, called exosomes, contribute to extracellular adenosine production and hence modulate immune effector cells indirectly. We found exosomes from diverse cancer cell types exhibit potent ATP- and 5'AMP-phosphohydrolytic activity, partly attributed to exosomally expressed CD39 and CD73, respectively. Comparable levels of activity were seen with exosomes from pleural effusions of mesothelioma patients. In such fluids, exosomes accounted for 20% of the total ATP-hydrolytic activity. Exosomes can perform both hydrolytic steps sequentially to form adenosine from ATP. This exosome-generated adenosine can trigger a cAMP response in adenosine A(2A) receptor-positive but not A(2A) receptor-negative cells. Similarly, significantly elevated cAMP was also triggered in Jurkat cells by adding exosomes with ATP but not by adding exosomes or ATP alone. A proportion of healthy donor T cells constitutively express CD39 and/or CD73. Activation of T cells by CD3/CD28 cross-linking could be inhibited by exogenously added 5'AMP in a CD73-dependent manner. However, 5'AMP converted to adenosine by exosomes inhibits T cell activation independently of T cell CD73 expression. This T cell inhibition was mediated through the adenosine A(2A) receptor. In summary, the data highlight exosome enzymic activity in the production of extracellular adenosine, and this may play a contributory role in negative modulation of T cells in the tumor environment. PMID:21677139

  11. The Adverse Events and Hemodynamic Effects of Adenosine-Based Cardiac MRI

    We wanted to prospectively assess the adverse events and hemodynamic effects associated with an intravenous adenosine infusion in patients with suspected or known coronary artery disease and who were undergoing cardiac MRI. One hundred and sixty-eight patients (64 ± 9 years) received adenosine (140 μg/kg/min) during cardiac MRI. Before and during the administration, the heart rate, systemic blood pressure, and oxygen saturation were monitored using a MRI-compatible system. We documented any signs and symptoms of potential adverse events. In total, 47 out of 168 patients (28%) experienced adverse effects, which were mostly mild or moderate. In 13 patients (8%), the adenosine infusion was discontinued due to intolerable dyspnea or chest pain. No high grade atrioventricular block, bronchospasm or other life-threatening adverse events occurred. The hemodynamic measurements showed a significant increase in the heart rate during adenosine infusion (69.3 ± 11.7 versus 82.4 ± 13.0 beats/min, respectively; p < 0.001). A significant but clinically irrelevant increase in oxygen saturation occurred during adenosine infusion (96 ± 1.9% versus 97 ± 1.3%, respectively; p < 0.001). The blood pressure did not significantly change during adenosine infusion (systolic: 142.8 ± 24.0 versus 140.9 ± 25.7 mmHg; diastolic: 80.2 ± 12.5 mmHg versus 78.9 ± 15.6, respectively). This study confirms the safety of adenosine infusion during cardiac MRI. A considerable proportion of all patients will experience minor adverse effects and some patients will not tolerate adenosine infusion. However, all adverse events can be successfully managed by a radiologist. The increased heart rate during adenosine infusion highlights the need to individually adjust the settings according to the patient, e.g., the number of slices of myocardial perfusion imaging.

  12. Severe hemorrhage attenuates cardiopulmonary chemoreflex control of regional sympathetic outputs via NTS adenosine receptors.

    Minic, Zeljka; Li, Cailian; O'Leary, Donal S; Scislo, Tadeusz J

    2014-09-15

    Selective stimulation of inhibitory A1 and facilitatory A2a adenosine receptor subtypes located in the nucleus of the solitary tract (NTS) powerfully inhibits cardiopulmonary chemoreflex (CCR) control of regional sympathetic outputs via different mechanisms: direct inhibition of glutamate release and facilitation of an inhibitory neurotransmitter release, respectively. However, it remains unknown whether adenosine naturally released into the NTS has similar inhibitory effects on the CCR as the exogenous agonists do. Our previous study showed that adenosine is released into the NTS during severe hemorrhage and contributes to reciprocal changes of renal (decreases) and adrenal (increases) sympathetic nerve activity observed in this setting. Both A1 and A2a adenosine receptors are involved. Therefore, we tested the hypothesis that, during severe hemorrhage, CCR control of the two sympathetic outputs is attenuated by adenosine naturally released into the NTS. We compared renal and adrenal sympathoinhibitory responses evoked by right atrial injections of 5HT3 receptor agonist phenylbiguanide (2-8 μg/kg) under control conditions, during hemorrhage, and during hemorrhage preceded by blockade of NTS adenosine receptors with bilateral microinjections of 8-(p-sulfophenyl) theophylline (1 nmol/100 nl) in urethane/chloralose anesthetized rats. CCR-mediated inhibition of renal and adrenal sympathetic activity was significantly attenuated during severe hemorrhage despite reciprocal changes in the baseline activity levels, and this attenuation was removed by bilateral blockade of adenosine receptors in the caudal NTS. This confirmed that adenosine endogenously released into the NTS has a similar modulatory effect on integration of cardiovascular reflexes as stimulation of NTS adenosine receptors with exogenous agonists. PMID:25063794

  13. Possible therapeutic benefits of adenosine-potentiating drugs in reducing age-related degenerative disease in dogs and cats.

    Scaramuzzi, R J; Baker, D J

    2003-10-01

    Adenosine is a ubiquitous, biologically important molecule that is a precursor of other biologically active molecules. It also is a component of some co-factors and has distinct physiological actions in its own right. Levels are maintained by synthesis from dietary precursors and re-cycling. The daily turnover of adenosine is very high. Adenosine can act either as a hormone by binding to adenosine receptors, four adenosine receptor subtypes have been identified, and as an intracellular modulator, after transport into the cell by membrane transporter proteins. One of the principal intracellular actions of adenosine is inhibition of the enzyme phosphodiesterase. Extracellular adenosine also has specific neuromodulatory actions on dopamine and glutamate. Selective and nonselective agonists and antagonists of adenosine are available. The tasks of developing, evaluating and exploiting the therapeutic potential of these compounds is still in its infancy. Adenosine has actions in the central nervous system (CNS), heart and vascular system, skeletal muscle and the immune system and the presence of receptors suggests potential actions in the gonads and other organs. Adenosine agonists improve tissue perfusion through actions on vascular smooth muscle and erythrocyte fluidity and they can be used to improve the quality of life in aged dogs. This article reviews the therapeutic potential of adenosine-potentiating drugs in the treatment of age-related conditions in companion animals, some of which may be exacerbated by castration or spaying at an early age. PMID:14633184

  14. Adenosine derived from Staphylococcus aureus-engulfed macrophages functions as a potent stimulant for the induction of inflammatory cytokines in mast cells

    Ma, Ying Jie; Kim, Chan-Hee; Ryu, Kyoung-Hwa; Kim, Min-Su; So, Young-In; Lee, Kong-Joo; Garred, Peter; Lee, Bok-Luel

    2011-01-01

    adenosine receptor blocker, verified that purified adenosine can induce interleukin-8 production via adenosine receptors on mast cells. Moreover, adenosine was purified from S. aureusengulfed RAW264.7 cells, a murine macrophage cell line, used to induce phagocytosis of S. aureus. These results show a novel...

  15. Intravenous infusion of adenosine but not inosine stimulates respiration in man.

    Reid, P G; Watt, A H; Routledge, P A; Smith, A P

    1987-01-01

    The effects on respiration of intravenous infusions of the endogenous nucleoside adenosine and its deaminated metabolite, inosine, administered in random order, single-blind, were compared in six healthy volunteers. The infusion rate of each nucleoside was initially 3.1 mg min-1 and was increased stepwise every 2 min, as tolerated, up to a possible maximum of 23.4 mg ml-1. The maximum dose rates received by all subjects were 8.5 mg min-1 for adenosine and 16.8 mg min-1 for inosine. Adenosine ...

  16. Receptor crosstalk: haloperidol treatment enhances A2A adenosine receptor functioning in a transfected cell model

    Trincavelli, Maria Letizia; Cuboni, Serena; Catena Dell’Osso, Mario; Maggio, Roberto; Klotz, Karl-Norbert; Novi, Francesca; Panighini, Anna; Daniele, Simona; Martini, Claudia

    2010-01-01

    A2A adenosine receptors are considered an excellent target for drug development in several neurological and psychiatric disorders. It is noteworthy that the responses evoked by A2A adenosine receptors are regulated by D2 dopamine receptor ligands. These two receptors are co-expressed at the level of the basal ganglia and interact to form functional heterodimers. In this context, possible changes in A2A adenosine receptor functional responses caused by the chronic blockade/activation of D2 dop...

  17. Dopamine/adenosine interactions involved in effort-related aspects of food motivation

    Salamone, John D.; Correa, Merce

    2009-01-01

    Nucleus accumbens dopamine (DA) is involved in effort-related aspects of food motivation. Accumbens DA depletions reduce the tendency of rats to work for food, and alter effort-related choice, but leave other aspects of food motivation and appetite intact. DA and adenosine receptors interact to regulate effort-related processes. Adenosine A2A antagonists can reverse the effects of DA D2 antagonists on effort-related choice, and intra-accumbens injections of a adenosine A2A agonist produce eff...

  18. Adenosine-induced hyperpolarization of the membrane voltage in rat mesangial cells in primary culture.

    Pavenstädt, H. (Hermann); Ruh, J; Greger, R; Schollmeyer, P.

    1994-01-01

    1. The effect of adenosine on membrane voltage and ion currents was studied in rat mesangial cells in primary culture. Membrane voltage was measured with the patch clamp technique in the slow- or fast whole cell configuration. The resting membrane voltage of mesangial cells was -48 +/- 0.5 mV. Adenosine (10(-8)-10(-3) M) induced a sustained and concentration-dependent hyperpolarization of membrane voltage (ED50 approximately 6 x 10(-7) M). Adenosine (10(-5) M) hyperpolarized the membrane volt...

  19. The role of adenosine A2A receptors on neuromuscular transmission upon ageing

    Pousinha, Paula Isabel Antunes, 1978-

    2012-01-01

    Tese de doutoramento, Ciências Biomédicas (Neurociências), Universidade de Lisboa, Faculdade de Medicina, 2012 Adenosine is a neuromodulator with important actions in the nervous system. The activation of adenosine A2A receptors has been shown to modulate the action of other receptors. Considering that it was observed an interaction between adenosine A2A receptors and TrkB receptors in hippocampus, I hypothesized that the activation of A2A receptors could also facilitate BDNF actions on ne...

  20. Role of endogenous adenosine in the expression of opiate withdrawal in rats.

    Salem, A; Hope, W

    1999-03-12

    Samples of extracellular fluid from striatum and nucleus accumbens of anaesthetised rats undergoing opiate withdrawal were collected using microdialysis and then analysed for adenosine and its metabolites using high performance liquid chromatography (HPLC) and ultraviolet (UV) detection. Although the amount of adenosine present in the dialysate from either brain region was below the limit of detection by 90 min after probe placement, the metabolites could still be detected. Samples of dialysates collected from the nucleus accumbens contained significantly higher concentrations of hypoxanthine and inosine following naloxone challenge. The data are compatible with the hypothesis that endogenous adenosine might be involved in the expression of the opiate abstinence syndrome. PMID:10204679

  1. Anti-Inflammatory and Immunosuppressive Effects of the A2A Adenosine Receptor

    Gillian R. Milne; Palmer, Timothy M.

    2011-01-01

    The production of adenosine represents a critical endogenous mechanism for regulating immune and inflammatory responses during conditions of stress, injury, or infection. Adenosine exerts predominantly protective effects through activation of four 7-transmembrane receptor subtypes termed A1, A2A, A2B, and A3, of which the A2A adenosine receptor (A2AAR) is recognised as a major mediator of anti-inflammatory responses. The A2AAR is widely expressed on cells of the immune system and numerous in ...

  2. Adenosine A2A receptor binding profile of two antagonists, ST1535 and KW6002: consideration on the presence of atypical adenosine A2A binding sites

    Teresa Riccioni

    2010-08-01

    Full Text Available Adenosine A2A receptors seem to exist in typical (more in striatum and atypical (more in hippocampus and cortex subtypes. In the present study, we investigated the affinity of two adenosine A2A receptor antagonists, ST1535 [2 butyl -9-methyl-8-(2H-1,2,3-triazol 2-yl-9H-purin-6-xylamine] and KW6002 [(E-1,3-diethyl-8-(3,4-dimethoxystyryl-7-methyl-3,7-dihydro-1H-purine-2,6,dione] to the “typical” and “atypical” A2A binding sites. Affinity was determined by radioligand competition experiments in membranes from rat striatum and hippocampus. Displacement of the adenosine analog [3H]CGS21680 [2-p-(2-carboxyethylphenethyl-amino-5’-N-ethylcarbox-amidoadenosine] was evaluated in the absence or in the presence of either CSC [8-(3-chlorostyryl-caffeine], an adenosine A2A antagonist that pharmacologically isolates atypical binding sites, or DPCPX (8-cyclopentyl-1,3-dipropylxanthine, an adenosine A1 receptor antagonist that pharmacologically isolates typical binding site. ZM241385 [84-(2-[7-amino-2-(2-furyl [1,2,4]-triazol[2,3-a][1,3,5]triazin-5-yl amino]ethyl phenol] and SCH58261 [(5-amino-7-(β-phenylethyl-2-(8-furylpyrazolo(4,3-e-1,2,4-triazolo(1,5-c pyrimidine], two other adenosine A2A receptor antagonists, which were reported to differently bind to atypical and typical A2A receptors, were used as reference compounds. ST1535, KW6002, ZM241385 and SCH58261 displaced [3H]CGS21680 with higher affinity in striatum than in hippocampus. In hippocampus, no typical adenosine A2A binding was detected, and ST1535 was the only compound that occupied atypical A2A adenosine receptors. Present data are explained in terms of heteromeric association among adenosine A2A, A2B and A1 receptors, rather than with the presence of atypical A2A receptor subtype.

  3. The role of muscarinic receptors in the beneficial effects of adenosine against myocardial reperfusion injury in rats.

    Lei Sun

    Full Text Available Adenosine, a catabolite of ATP, displays a wide variety of effects in the heart including regulation of cardiac response to myocardial ischemia and reperfusion injury. Nonetheless, the precise mechanism of adenosine-induced cardioprotection is still elusive. Isolated Sprague-Dawley rat hearts underwent 30 min global ischemia and 120 min reperfusion using a Langendorff apparatus. Both adenosine and acetylcholine treatment recovered the post-reperfusion cardiac function associated with adenosine and muscarinic receptors activation. Simultaneous administration of adenosine and acetylcholine failed to exert any additive protective effect, suggesting a shared mechanism between the two. Our data further revealed a cross-talk between the adenosine and acetylcholine receptor signaling in reperfused rat hearts. Interestingly, the selective M(2 muscarinic acetylcholine receptor antagonist methoctramine significantly attenuated the cardioprotective effect of adenosine. In addition, treatment with adenosine upregulated the expression and the maximal binding capacity of muscarinic acetylcholine receptor, which were inhibited by the selective A(1 adenosine receptor antagonist 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX and the nitric oxide synthase inhibitor N(ω-nitro-L-arginine methyl ester (L-NAME. These data suggested a possible functional coupling between the adenosine and muscarinic receptors behind the observed cardioprotection. Furthermore, nitric oxide was found involved in triggering the response to each of the two receptor agonist. In summary, there may be a cross-talk between the adenosine and muscarinic receptors in ischemic/reperfused myocardium with nitric oxide synthase might serve as the distal converging point. In addition, adenosine contributes to the invigorating effect of adenosine on muscarinic receptor thereby prompting to regulation of cardiac function. These findings argue for a potentially novel mechanism behind the adenosine

  4. Adenosine formation in contracting primary rat skeletal muscle cells and endothelial cells in culture

    Hellsten, Ylva; Frandsen, Ulrik

    1997-01-01

    1. The present study examined the capacity for adenosine formation, uptake and metabolism in contracting primary rat muscle cells and in microvascular endothelial cells in culture. 2. Strong and moderate electrical simulation of skeletal muscle cells led to a significantly greater increase in the...... extracellular adenosine concentration (421 +/- 91 and 235 +/- 30 nmol (g protein)-1, respectively; P < 0.05) compared with non-stimulated muscle cells (161 +/- 20 nmol (g protein)-1). The ATP concentration was lower (18%; P < 0.05) in the intensely contracted, but not in the moderately contracted muscle cells....... 3. Addition of microvascular endothelial cells to the cultured skeletal muscle cells enhanced the contraction-induced accumulation of extracellular adenosine (P < 0.05), whereas endothelial cells in culture alone did not cause extracellular accumulation of adenosine. 4. Skeletal muscle cells were...

  5. Laboratory procedures manual for the firefly luciferase assay for adenosine triphosphate (ATP)

    Chappelle, E. W.; Picciolo, G. L.; Curtis, C. A.; Knust, E. A.; Nibley, D. A.; Vance, R. B.

    1975-01-01

    A manual on the procedures and instruments developed for the adenosine triphosphate (ATP) luciferase assay is presented. Data cover, laboratory maintenance, maintenance of bacterial cultures, bacteria measurement, reagents, luciferase procedures, and determination of microbal susceptibility to antibiotics.

  6. Acute hyperammonemia and systemic inflammation is associated with increased extracellular brain adenosine in rats

    Bjerring, Peter Nissen; Dale, Nicholas; Larsen, Fin Stolze

    2015-01-01

    Acute liver failure (ALF) can lead to brain edema, cerebral hyperperfusion and intracranial hypertension. These complications are thought to be mediated by hyperammonemia and inflammation leading to altered brain metabolism. As increased levels of adenosine degradation products have been found in...... cerebral blood flow (CBF). We measured the adenosine concentration with biosensors in rat brain slices exposed to ammonia and in a rat model with hyperammonemia and systemic inflammation. Exposure to ammonia in concentrations from 0.15-10 mM led to increases in the cortical adenosine concentration up to 18...... µM in brain slices. In vivo recordings showed a tendency towards increased adenosine levels in rats with hyperammonemia and systemic inflammation compared to a control group (3.7 ± 0.7 vs. 0.8 ± 0.2 µM, P = 0.06). This was associated with a significant increase in ICP and CBF. Intervention with the...

  7. Actinides and rare earths complexation with adenosine phosphate nucleotides

    Organophosphorus compounds are important molecules in both nuclear industry and living systems fields. Indeed, several extractants of organophosphorus compounds (such as TBP, HDEHP) are used in the nuclear fuel cycle reprocessing and in the biological field. For instance, the nucleotides are organophosphates which play a very important role in various metabolic processes. Although the literature on the interactions of actinides with inorganic phosphate is abundant, published studies with organophosphate compounds are generally limited to macroscopic and / or physiological approaches. The objective of this thesis is to study the structure of several organophosphorus compounds with actinides to reach a better understanding and develop new specific buildings blocks. The family of the chosen molecules for this procedure consists of three adenine nucleotides mono, bi and triphosphate (AMP, adenosine monophosphate - ADP, adenosine diphosphate - ATP, adenosine triphosphate) and an amino-alkylphosphate (AEP O-phosphoryl-ethanolamine). Complexes synthesis was conducted in aqueous and weakly acidic medium (2.8-4) for several lanthanides (III) (Lu, Yb, Eu) and actinides (U (VI), Th (IV) and Am (III)). Several analytical and spectroscopic techniques have been used to describe the organization of the synthesized complexes: spectrometric analysis performed by FTIR and NMR were used to identify the functional groups involved in the complexation, analysis by ESI-MS and pH-metric titration were used to determine the solution speciation and EXAFS analyzes were performed on Mars beamline of the SOLEIL synchrotron, have described the local cation environment, for both solution and solid compounds. Some theoretical approaches of DFT were conducted to identify stable structures in purpose of completing the experimental studies. All solid complexes (AMP, ADP, ATP and AEP) have polynuclear structures, while soluble ATP complexes are mononuclear. For all synthesized complexes, it has been

  8. Adenosine, Caffeine, and Performance: From Cognitive Neuroscience of Sleep to Sleep Pharmacogenetics

    Urry, Emily; Landolt, Hans-Peter

    2014-01-01

    An intricate interplay between circadian and sleep-wake homeostatic processes regulate cognitive performance on specific tasks, and individual differences in circadian preference and sleep pressure may contribute to individual differences in distinct neurocognitive functions. Attentional performance appears to be particularly sensitive to time of day modulations and the effects of sleep deprivation. Consistent with the notion that the neuromodulator, adenosine adenosine , plays an important r...

  9. Reduced striatal ecto-nucleotidase activity in schizophrenia patients supports the “adenosine hypothesis”

    Aliagas, Elisabet; Villar-Menéndez, Izaskun; Sévigny, Jean; Roca, Mercedes; Romeu, Miriam; Ferrer, Isidre; Martín-Satué, Mireia; Barrachina, Marta

    2013-01-01

    Schizophrenia (SZ) is a major chronic neuropsychiatric disorder characterized by a hyperdopaminergic state. The hypoadenosinergic hypothesis proposes that reduced extracellular adenosine levels contribute to dopamine D2 receptor hyperactivity. ATP, through the action of ecto-nucleotidases, constitutes a main source of extracellular adenosine. In the present study, we examined the activity of ecto-nucleotidases (NTPDases, ecto-5′-nucleotidase, and alkaline phosphatase) in the postmortem putame...

  10. Cordycepin Increases Nonrapid Eye Movement Sleep via Adenosine Receptors in Rats

    Zhenzhen Hu; Chung-Il Lee; Vikash Kumar Shah; Eun-Hye Oh; Jin-Yi Han; Jae-Ryong Bae; Kinam Lee; Myong-Soo Chong; Jin Tae Hong; Ki-Wan Oh

    2013-01-01

    Cordycepin (3′-deoxyadenosine) is a naturally occurring adenosine analogue and one of the bioactive constituents isolated from Cordyceps militaris/Cordyceps sinensis, species of the fungal genus Cordyceps. It has traditionally been a prized Chinese folk medicine for the human well-being. Because of similarity of chemical structure of adenosine, cordycepin has been focused on the diverse effects of the central nervous systems (CNSs), like sleep regulation. Therefore, this study was undertaken ...

  11. Regulation of aggregate size and pattern by adenosine and caffeine in cellular slime molds

    Jaiswal Pundrik; Soldati Thierry; Thewes Sascha; Baskar Ramamurthy

    2012-01-01

    Abstract Background Multicellularity in cellular slime molds is achieved by aggregation of several hundreds to thousands of cells. In the model slime mold Dictyostelium discoideum, adenosine is known to increase the aggregate size and its antagonist caffeine reduces the aggregate size. However, it is not clear if the actions of adenosine and caffeine are evolutionarily conserved among other slime molds known to use structurally unrelated chemoattractants. We have examined how the known factor...

  12. Local adenosine receptor blockade accentuates the sympathetic responses to fatiguing exercise

    Cui, Jian; Leuenberger, Urs A.; Blaha, Cheryl; Yoder, Jonathan; Gao, Zhaohui; Sinoway, Lawrence I.

    2010-01-01

    The role adenosine plays in evoking the exercise pressor reflex in humans remains controversial. We hypothesized that localized forearm adenosine receptor blockade would attenuate muscle sympathetic nerve activity (MSNA) responses to fatiguing handgrip exercise in humans. Blood pressure (Finometer), heart rate, and MSNA from the peroneal nerve were assessed in 11 healthy young volunteers during fatiguing isometric handgrip, postexercise circulatory occlusion (PECO), and passive muscle stretch...

  13. Severe hemorrhage attenuates cardiopulmonary chemoreflex control of regional sympathetic outputs via NTS adenosine receptors

    Minic, Zeljka; Li, Cailian; O'Leary, Donal S.; Scislo, Tadeusz J.

    2014-01-01

    Selective stimulation of inhibitory A1 and facilitatory A2a adenosine receptor subtypes located in the nucleus of the solitary tract (NTS) powerfully inhibits cardiopulmonary chemoreflex (CCR) control of regional sympathetic outputs via different mechanisms: direct inhibition of glutamate release and facilitation of an inhibitory neurotransmitter release, respectively. However, it remains unknown whether adenosine naturally released into the NTS has similar inhibitory effects on the CCR as th...

  14. Methotrexate inhibits neutrophil function by stimulating adenosine release from connective tissue cells.

    Cronstein, B. N.; Eberle, M A; Gruber, H E; Levin, R I

    1991-01-01

    Although commonly used to control a variety of inflammatory diseases, the mechanism of action of a low dose of methotrexate remains a mystery. Methotrexate accumulates intracellularly where it may interfere with purine metabolism. Therefore, we determined whether a 48-hr pretreatment with methotrexate affected adenosine release from [14C]adenine-labeled human fibroblasts and umbilical vein endothelial cells. Methotrexate significantly increased adenosine release by fibroblasts from 4 +/- 1% t...

  15. Radio-chromatographic determination of plasmatic adenosine deaminase (A.D.)

    We were able, by using a radio-chromatographic method, to measure an adenosine deaminase activity in normal human heparinized platelet-poor plasma, which can degrade 0.016 μM adenosine. This activity suppressed by heating 56 C for 30 minutes is inhibited by high concentrations of urea and is proportional to the amount of plasma, source of enzyme, in the systems. (authors)

  16. Aptamer-based Electrochemical Biosensors for Highly Selective and Quantitative Detection of Adenosine

    ZHENG Fan; WU Zai-sheng; ZHANG Song-bai; GUO Meng-meng; CHEN Chen-rui; SHEN Guo-li; YU Ru-qin

    2008-01-01

    A new adenosine biosensor based on aptamer probe is introduced in this article.An amino-labeled aptamer probe was immobilized on the gold electrode modified with an o-phenylenediamine electropolymerized film.When adenosine is bound specifically to the aptamer probe,the interface of the biosensor is changed,resulting in the decrement of the peak current.The response current is proportional to the amount of adenosine in sample.The used electrode can be easily regenerated in hot water.The proposed biosensor represents a linear response to adenosine over a concentration range of 1.0×10-7-1.0×10-4 mol/L with a detection limit of 1.0×10-8 mol/L.The presented biosensor exhibits a nice specificity towards adenosine.It offers a promising approach for adenosine assay due to its excellent electrochemical properties that are believed to be very attractive for electrochemical studies and electroanalytical applications.

  17. Serum adenosine deaminase as oxidative stress marker in type 2 diabetes mellitus

    Shashikala Magadi Dasegowda

    2015-05-01

    Results: The study observed an increased level of serum adenosine deaminase, malondialdehyde and decreased levels of total antioxidant capacity in type 2 diabetes mellitus compared to controls. Serum adenosine deaminase levels in type 2 diabetics were 50.77 +/- 6.95 and in controls was 17.86 +/- 4.04. Serum Malondialdehyde levels in type 2 diabetics was 512.13 +/- 70.15 and in controls was 239.32 +/- 23.97. Serum total antioxidant levels in type 2 diabetics was 0.39+/-0.15 and in controls was 1.66+/-0.25. Positive correlation was seen between serum adenosine deaminase and malondialdehyde and it was statistically significant. Statistically significant negative correlation was seen between serum adenosine deaminase and total antioxidant capacity. Conclusion: Adenosine deaminase can be used as oxidative stress marker. Their increased levels indicate oxidative stress in type 2 diabetes mellitus. Therefore, estimation of serum adenosine deaminase levels help in early prediction and prevention of long term complications occurring due to oxidative stress in diabetics, thereby decreasing the mortality and morbidity in them. [Int J Res Med Sci 2015; 3(5.000: 1195-1198

  18. Methotrexate inhibits neutrophil function by stimulating adenosine release from connective tissue cells

    Although commonly used to control a variety of inflammatory diseases, the mechanism of action of a low dose of methotrexate remains a mystery. Methotrexate accumulates intracellularly where it may interfere with purine metabolism. Therefore, the authors determined whether a 48-hr pretreatment with methotrexate affected adenosine release from [14C]adenine-labeled human fibroblasts and umbilical vein endothelial cells. Methotrexate significantly increased adenosine release by fibroblasts. The effect of methotrexate on adenosine release was not due to cytotoxicity since cells treated with maximal concentrations of methotrexate took up [14C]adenine and released 14C-labeled purine (a measure of cell injury) in a manner identical to control cells. Methotrexate treatment of fibroblasts dramatically inhibited adherence to fibroblasts by both unstimulated neutrophils and stimulated neutrophils. One hypothesis that explains the effect of methotrexate on adenosine release is that, by inhibition of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase, methotrexate induces the accumulation of AICAR, the nucleoside precursor of which has previously been shown to cause adenosine release from ischemic cardiac tissue. The observation that the antiinflammatory actions of methotrexate are due to the capacity of methotrexate to induce adenosine release may form the basis for the development of an additional class of antiinflammatory drugs

  19. Intravenous adenosine (adenoscan) versus exercise in the noninvasive assessment of coronary artery disease by SPECT

    LaManna, M.M.; Mohama, R.; Slavich, I.L. 3d.; Lumia, F.J.; Cha, S.D.; Rambaran, N.; Maranhao, V. (Deborah Heart and Lung Center, Browns Mills, NJ (USA))

    1990-11-01

    Fifteen patients at a mean age of 58 underwent adenosine and maximal exercise thallium SPECT imaging. All scans were performed 1 week apart and within 4 weeks of cardiac catheterization. SPECT imaging was performed after the infusion of 140 micrograms/kg/min of adenosine for 6 minutes. Mean heart rate increment during adenosine administration was 67 +/- 3.7 to 77 +/- 4.1. Mean blood pressure was 136 +/- 7.2 to 135 +/- 6.2 systolic and 78 +/- 1.8 to 68 +/- 2.6 diastolic. No adverse hemodynamic effects were observed. There were no changes in PR or QRS in intervals. Five stress ECGs were ischemic. No ST changes were observed with adenosine. Although 68% of the patients had symptoms of flushing, light-headedness, and dizziness during adenosine infusion, symptoms resolved within 1 minute of dosage adjustment or termination of the infusion in all but one patient, who required theophylline. Sensitivity for coronary artery detection was 77% and specificity 100%. Concordance between adenoscans and exercise thallium scintigraphy was high (13/15 = 87%). In two patients, there were minor scintigraphic differences. The authors conclude that adenosine is a sensitive, specific, and safe alternative to exercise testing in patients referred for thallium imaging and may be preferable to dipyridamole.

  20. Suppression of adenosine-activated chloride transport by ethanol in airway epithelia.

    Sammeta V Raju

    Full Text Available Alcohol abuse is associated with increased lung infections. Molecular understanding of the underlying mechanisms is not complete. Airway epithelial ion transport regulates the homeostasis of airway surface liquid, essential for airway mucosal immunity and lung host defense. Here, air-liquid interface cultures of Calu-3 epithelial cells were basolaterally exposed to physiologically relevant concentrations of ethanol (0, 25, 50 and 100 mM for 24 hours and adenosine-stimulated ion transport was measured by Ussing chamber. The ethanol exposure reduced the epithelial short-circuit currents (I(SC in a dose-dependent manner. The ion currents activated by adenosine were chloride conductance mediated by cystic fibrosis transmembrane conductance regulator (CFTR, a cAMP-activated chloride channel. Alloxazine, a specific inhibitor for A(2B adenosine receptor (A(2BAR, largely abolished the adenosine-stimulated chloride transport, suggesting that A(2BAR is a major receptor responsible for regulating the chloride transport of the cells. Ethanol significantly reduced intracellular cAMP production upon adenosine stimulation. Moreover, ethanol-suppression of the chloride secretion was able to be restored by cAMP analogs or by inhibitors to block cAMP degradation. These results imply that ethanol exposure dysregulates CFTR-mediated chloride transport in airways by suppression of adenosine-A(2BAR-cAMP signaling pathway, which might contribute to alcohol-associated lung infections.

  1. Functional proteomics of adenosine triphosphatase system in the rat striatum during aging

    Roberto Federico Villa; Federica Ferrari; Antonella Gorini

    2012-01-01

    The maximum rates of adenosine triphosphatase (ATPase) systems related to energy consumption were systematically evaluated in synaptic plasma membranes isolated from the striata of male Wistar rats aged 2, 6, 12, 18, and 24 months, because of their key role in presynaptic nerve ending homeostasis. The following enzyme activities were evaluated: sodium-potassium-magnesium adenosine triphosphatase (Na+, K+, Mg2+-ATPase); ouabain-insensitive magnesium adenosine triphosphatase (Mg2+-ATPase); sodium-potassium adenosine triphosphatase (Na+, K+-ATPase); direct magnesium adenosine triphosphatase (Mg2+-ATPase); calcium-magnesium adenosine triphosphatase (Ca2+, Mg2+-ATPase); and acetylcholinesterase. The results showed that Na+, K+-ATPase decreased at 18 and 24 months, Ca2+, Mg2+-ATPase and acetylcholinesterase decreased from 6 months, while Mg2+-ATPase was unmodified. Therefore, ATPases vary independently during aging, suggesting that the ATPase enzyme systems are of neuropathological and pharmacological importance. This could be considered as an experimental model to study regeneration processes, because of the age-dependent modifications of specific synaptic plasma membranes. ATPases cause selective changes in some cerebral functions, especially bioenergetic systems. This could be of physiopathological significance, particularly in many central nervous system diseases, where, during regenerative processes, energy availability is essential.

  2. Adenosine concentration in the porcine coronary artery wall and A2A receptor involvement in hypoxia-induced vasodilatation

    Frøbert, Ole; Haink, Gesine; Simonsen, Ulf; Gravholt, Claus H; Levin, Max; Deussen, Andreas

    2006-01-01

    We tested whether hypoxia-induced coronary artery dilatation could be mediated by an increase in adenosine concentration within the coronary artery wall or by an increase in adenosine sensitivity. Porcine left anterior descendent coronary arteries, precontracted with prostaglandin F2α (10−5m), were mounted in a pressure myograph and microdialysis catheters were inserted into the tunica media. Dialysate adenosine concentrations were analysed by HPLC. Glucose, lactate and pyruvate were measured by an automated spectrophotometric kinetic enzymatic analyser. The exchange fraction of [14C]adenosine over the microdialysis membrane increased from 0.32 ± 0.02 to 0.46 ± 0.02 (n = 4, P < 0.01) during the study period. At baseline, interstitial adenosine was in the region of 10 nm which is significantly less than previously found myocardial concentrations. Hypoxia (PO2 30 mmHg for 60 min, n = 5) increased coronary diameters by 20.0 ± 2.6% (versus continuous oxygenation −3.1 ± 2.4%, n = 6, P < 0.001) but interstitial adenosine concentration fell. Blockade of adenosine deaminase (with erythro-9-(2-hydroxy-3-nonyl-)-adenine, 5 μm), adenosine kinase (with iodotubericidine, 10 μm) and adenosine transport (with n-nitrobenzylthioinosine, 1 μm) increased interstitial adenosine but the increase was unrelated to hypoxia or diameter. A coronary dilatation similar to that during hypoxia could be obtained with 30 μm of adenosine in the organ bath and the resulting interstitial adenosine concentrations (n = 5) were 20 times higher than the adenosine concentration measured during hypoxia. Adenosine concentration–response experiments showed vasodilatation to be more pronounced during hypoxia (n = 9) than during normoxia (n = 9, P < 0.001) and the A2A receptor antagonist ZM241385 (20 nm, n = 5), attenuated hypoxia-induced vasodilatation while the selective A2B receptor antagonist MRS1754 (20 nm, n = 4), had no effect. The lactate/pyruvate ratio was significantly increased in

  3. Adenosine to Inosine editing frequency controlled by splicing efficiency.

    Licht, Konstantin; Kapoor, Utkarsh; Mayrhofer, Elisa; Jantsch, Michael F

    2016-07-27

    Alternative splicing and adenosine to inosine (A to I) RNA-editing are major factors leading to co- and post-transcriptional modification of genetic information. Both, A to I editing and splicing occur in the nucleus. As editing sites are frequently defined by exon-intron basepairing, mRNA splicing efficiency should affect editing levels. Moreover, splicing rates affect nuclear retention and will therefore also influence the exposure of pre-mRNAs to the editing-competent nuclear environment. Here, we systematically test the influence of splice rates on RNA-editing using reporter genes but also endogenous substrates. We demonstrate for the first time that the extent of editing is controlled by splicing kinetics when editing is guided by intronic elements. In contrast, editing sites that are exclusively defined by exonic structures are almost unaffected by the splicing efficiency of nearby introns. In addition, we show that editing levels in pre- and mature mRNAs do not match. This phenomenon can in part be explained by the editing state of an RNA influencing its splicing rate but also by the binding of the editing enzyme ADAR that interferes with splicing. PMID:27112566

  4. Adenosine, type 1 receptors: role in proximal tubule Na+ reabsorption.

    Welch, W J

    2015-01-01

    Adenosine type 1 receptor (A1 -AR) antagonists induce diuresis and natriuresis in experimental animals and humans. Much of this effect is due to inhibition of A1 -ARs in the proximal tubule, which is responsible for 60-70% of the reabsorption of filtered Na(+) and fluid. Intratubular application of receptor antagonists indicates that A1 -AR mediates a portion of Na(+) uptake in PT and PT cells, via multiple transport systems, including Na(+) /H(+) exchanger-3 (NHE3), Na(+) /PO4(-) co-transporter and Na(+) -dependent glucose transporter, SGLT. Renal microperfusion and recollection studies have shown that fluid reabsorption is reduced by A1 -AR antagonists and is lower in A1 -AR KO mice, compared to WT mice. Absolute proximal reabsorption (APR) measured by free-flow micropuncture is equivocal, with studies that show either lower APR or similar APR in A1 -AR KO mice, compared to WT mice. Inhibition of A1 -ARs lowers elevated blood pressure in models of salt-sensitive hypertension, partially due to their effects in the proximal tubule. PMID:25345761

  5. In Vitro Functional Study of Rice Adenosine 5'-Phosphosulfate Kinase

    WANG De-zhen; CHEN Guo-guo; LU Lu-jia; JIANG Zhao-jun; RAO Yu-chun; SUN Mei-hao

    2016-01-01

    Sulfate can be activated by ATP sulfurylase and adenosine 5'-phosphosulfate kinase (APSK)in vivo. Recent studies suggested that APSK inArabidopsis thaliana regulated the partition between APS reduction and phosphorylation and its activity can be modulated by cellular redox status. In order to study regulation of APSK in rice (OsAPSK),OsAPSK1 gene was cloned and its activity was analyzed. OsAPSK1 C36 and C69 were found to be the conserved counterparts of C86 and C119, which involved in disulfide formation in AtAPSK.C36A/C69A OsAPSK1 double mutation was made by site directed mutagenesis. OsAPSK1 and its mutant were prokaryotically over-expressed and purified, and then assayed for APS phosphorylation activity. OsAPSK1 activity was depressed by oxidized glutathione, while the activity of its mutantwas not. Further studies in the case that oxidative stress will fluctuatein vivo3'-phosphoadenosine-5'-phosphosulfate content, and all APSK isoenzymes have similar regulation patterns are necessary to be performed.

  6. Adenosine preconditioning attenuates hepatic reperfusion injury in the rat by preventing the down-regulation of endothelial nitric oxide synthase

    Serracino-Inglott, Ferdinand; Virlos, Ioannis T; Habib, Nagy A; Williamson, Robin CN; Mathie, Robert T

    2002-01-01

    Background Previous work has suggested that in the liver, adenosine preconditioning is mediated by nitric oxide. Whether the endothelial isoform of nitric oxide synthase plays a part in this mechanism has however not yet been investigated. Methods Wistar rats were used (6 in each group) – Groups: (1) sham, (2) ischemia-reperfusion, (3) adenosine + ischemia-reperfusion, (4) endothelial isoform inhibitor + adenosine + ischemia-reperfusion. Results Using immunohistochemistry, this study has revealed a decrease in the expression of endothelial nitric oxide synthase following hepatic ischemia-reperfusion. This was prevented by adenosine pre-treatment. When an inhibitor of endothelial nitric oxide synthase was administered prior to adenosine pre-treatment, pre-conditioning did not occur despite normal expression of endothelial nitric oxide synthase. Conclusions These findings suggest that adenosine attenuates hepatic injury by preventing the downregulation of endothelial nitric oxide synthase that occurs during ischemia-reperfusion. PMID:12241560

  7. Radio-chromatographic determination of plasmatic adenosine deaminase (A.D.); Determination radiochromatographique de l'adenosine deaminase (A.D.)

    Chivot, J.J.; Depernet, D.; Caen, J. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1970-07-01

    We were able, by using a radio-chromatographic method, to measure an adenosine deaminase activity in normal human heparinized platelet-poor plasma, which can degrade 0.016 {mu}M adenosine. This activity suppressed by heating 56 C for 30 minutes is inhibited by high concentrations of urea and is proportional to the amount of plasma, source of enzyme, in the systems. (authors) [French] Nous avons pu, en utilisant une methode radiochromatographique, mesurer une activite adenosine deaminasique dans le plasma humain pauvre en plaquettes heparine qui peut degrader 0,016 {mu}M d'adenosine. Cette activite qui est supprimee par chauffage a 56 degres pendant 30 minutes, est reduite par conservation a -20 C pendant une semaine, est inhibee par d'importantes concentrations d'uree et ne l'est pas, ni par le dipyridamol, ni par le pHMB. Cette activite est proportionnelle a la quantite de plasma, source d'enzyme, mise dans les differents systemes reactifs. (auteur)

  8. Adenosine elicits an eNOS-independent reduction in arterial blood pressure in conscious mice that involves adenosine A(2A) receptors

    Andersen, Henrik; Jaff, Mohammad G; Høgh, Ditte;

    2011-01-01

    Aims:  Adenosine plays an important role in the regulation of heart rate and vascular reactivity. However, the mechanisms underlying the acute effect of adenosine on arterial blood pressure in conscious mice are unclear. Therefore, the present study investigated the effect of the nucleoside on mean...... arterial blood pressure (MAP) and heart rate (HR) in conscious mice. Methods:  Chronic indwelling catheters were placed in C57Bl/6J (WT) and endothelial nitric oxide synthase knock-out (eNOS(-/-) ) mice for continuous measurements of MAP and HR. Using PCR and myograph analysis involment of adenosine...... receptors was investigated in human and mouse renal blood vessels Results:  Bolus infusion of 0.5 mg/kg adenosine elicited significant transient decreases in MAP (99.3±2.3 to 70.4±4.5 mmHg) and HR (603.2±18.3 to 364.3±49.2 min(-1) ) which were inhibited by the A(2A) receptor antagonist ZM 241385. Activation...

  9. Comparative study of adenosine deaminase activity, insulin resistance and lipoprotein(a) among smokers and healthy non-smokers

    Ramesh Ramasamy; Sathish Babu Murugaiyan; Arulkumaran U.; Sathiya R.; Kuzhandai Velu V.; Niranjan Gopal

    2016-01-01

    Background: Adenosine deaminase also known as adenosine aminohydrolase involved in purine metabolism. Its primary function is development and maintenance of immune system. The main objective of the study was to estimate adenosine deaminase (ADA) enzyme and find its correlation with lipoprotein(a) and insulin resistance among smokers and healthy non-smokers. Methods: Fifty smokers and fifty healthy non-smokers were selected based on WHO definition. ADA, lipid profile and glucose was estimat...

  10. Sleep-wake sensitive mechanisms of adenosine release in the basal forebrain of rodents: an in vitro study.

    Robert Edward Sims

    Full Text Available Adenosine acting in the basal forebrain is a key mediator of sleep homeostasis. Extracellular adenosine concentrations increase during wakefulness, especially during prolonged wakefulness and lead to increased sleep pressure and subsequent rebound sleep. The release of endogenous adenosine during the sleep-wake cycle has mainly been studied in vivo with microdialysis techniques. The biochemical changes that accompany sleep-wake status may be preserved in vitro. We have therefore used adenosine-sensitive biosensors in slices of the basal forebrain (BFB to study both depolarization-evoked adenosine release and the steady state adenosine tone in rats, mice and hamsters. Adenosine release was evoked by high K(+, AMPA, NMDA and mGlu receptor agonists, but not by other transmitters associated with wakefulness such as orexin, histamine or neurotensin. Evoked and basal adenosine release in the BFB in vitro exhibited three key features: the magnitude of each varied systematically with the diurnal time at which the animal was sacrificed; sleep deprivation prior to sacrifice greatly increased both evoked adenosine release and the basal tone; and the enhancement of evoked adenosine release and basal tone resulting from sleep deprivation was reversed by the inducible nitric oxide synthase (iNOS inhibitor, 1400 W. These data indicate that characteristics of adenosine release recorded in the BFB in vitro reflect those that have been linked in vivo to the homeostatic control of sleep. Our results provide methodologically independent support for a key role for induction of iNOS as a trigger for enhanced adenosine release following sleep deprivation and suggest that this induction may constitute a biochemical memory of this state.

  11. A2A adenosine receptor-mediated increase in coronary flow in hyperlipidemic APOE–knockout mice

    Teng, Bunyen

    2011-01-01

    Bunyen Teng, S Jamal MustafaDepartment of Physiology and Pharmacology and Center for Cardiovascular and Respiratory Sciences, West Virginia University, Morgantown, WV, USAAbstract: Adenosine-induced coronary vasodilation is predominantly A2A adenosine receptor (AR)-mediated, whereas A1 AR is known to negatively modulate the coronary flow (CF). However, the coronary responses to adenosine in hyperlipidemia and atherosclerosis are not well understood. Using hyperlipidemic/atherosclerotic apolip...

  12. Modulation of adenosine A(2A) receptor function by interacting proteins. New targets for Huntington’s disease

    Bakešová, Jana

    2012-01-01

    [eng] In this dissertation we studied the pharmacological and functional consequences of adenosine A2A receptor interaction with other proteins, as other neurotransmitter receptores localized in the human brain and an important enzyme regulating the extracellular concentration of adenosine, the ecto-ADA (adenosine desaminase). The first aim of this thesis was to study the molecular and functional interaction of A(2A)Rwith ADA. We found out that A(2A)Racted as a membrane anchoring protein of A...

  13. Adenosine deaminase regulates Treg expression in autologous T cell-dendritic cell cocultures from patients infected with HIV-1.

    Naval-Macabuhay, Isaac; Casanova, Víctor; Navarro, Gemma; García, Felipe; León, Agathe; Miralles, Laia; Rovira, Cristina; Martinez-Navio, José M; Gallart, Teresa; Mallol, Josefa; Gatell, José M; Lluís, Carme; Franco, Rafael; McCormick, Peter J; Climent, Núria

    2016-02-01

    Regulatory T cells have an important role in immune suppression during HIV-1 infection. As regulatory T cells produce the immunomodulatory molecule adenosine, our aim here was to assess the potential of adenosine removal to revert the suppression of anti-HIV responses exerted by regulatory T cells. The experimental setup consisted of ex vivo cocultures of T and dendritic cells, to which adenosine deaminase, an enzyme that hydrolyzes adenosine, was added. In cells from healthy individuals, adenosine hydrolysis decreased CD4(+)CD25(hi) regulatory T cells. Addition of 5'-N-ethylcarboxamidoadenosine, an adenosine receptor agonist, significantly decreased CD4(+)CD25(lo) cells, confirming a modulatory role of adenosine acting via adenosine receptors. In autologous cocultures of T cells with HIV-1-pulsed dendritic cells, addition of adenosine deaminase led to a significant decrease of HIV-1-induced CD4(+)CD25(hi) forkhead box p3(+) cells and to a significant enhancement of the HIV-1-specific CD4(+) responder T cells. An increase in the effector response was confirmed by the enhanced production of CD4(+) and CD8(+) CD25(-)CD45RO(+) memory cell generation and secretion of Th1 cytokines, including IFN-γ and IL-15 and chemokines MIP-1α/CCL3, MIP-1β/CCL4, and RANTES/CCL5. These ex vivo results show, in a physiologically relevant model, that adenosine deaminase is able to enhance HIV-1 effector responses markedly. The possibility to revert regulatory T cell-mediated inhibition of immune responses by use of adenosine deaminase, an enzyme that hydrolyzes adenosine, merits attention for restoring T lymphocyte function in HIV-1 infection. PMID:26310829

  14. Chronic hypoxia enhances adenosine release in rat PC12 cells by altering adenosine metabolism and membrane transport.

    Kobayashi, S; Zimmermann, H; Millhorn, D E

    2000-02-01

    Acute exposure to hypoxia causes a release of adenosine (ADO) that is inversely related to the O2 levels in oxygen-sensitive pheochromocytoma (PC12) cells. In the current study, chronic exposure (48 h) of PC12 cells to moderate hypoxia (5% O2) significantly enhanced the release of ADO during severe, acute hypoxia (1% O2). Investigation into the intra- and extracellular mechanisms underpinning the secretion of ADO in PC12 cells chronically exposed to hypoxia revealed changes in gene expression and activities of several key enzymes associated with ADO production and metabolism, as well as the down-regulation of a nucleoside transporter. Decreases in the enzymatic activities of ADO kinase and ADO deaminase accompanied by an increase in those of cytoplasmic and ecto-5'-nucleotidases bring about an increased capacity to produce intra- and extracellular ADO. This increased potential to generate ADO and decreased capacity to metabolize ADO indicate that PC12 cells shift toward an ADO producer phenotype during hypoxia. The reduced function of the rat equilibrative nucleoside transporter rENT1 also plays a role in controlling extracellular ADO levels. The hypoxia-induced alterations in the ADO metabolic enzymes and the rENT1 transporter seem to increase the extracellular concentration of ADO. The biological significance of this regulation is unclear but is likely to be associated with modulating cellular activity during hypoxia. PMID:10646513

  15. Angina pectoris-like pain provoked by intravenous adenosine in healthy volunteers.

    Sylvén, C; Beermann, B; Jonzon, B; Brandt, R

    1986-07-26

    In a study to characterise the chest pain induced by adenosine this agent was given as a bolus into a peripheral vein to six healthy volunteers (five men) aged 30-44. On the first day the maximum tolerable dose was determined in each case. On the second day three doses of adenosine (one third, two thirds, and the full maximum tolerable dose) and three doses of saline were given single blind in randomised order. Thereafter aminophylline 5 mg/kg was given and the procedure repeated in a different randomised order. On the third day between two thirds and the full maximum tolerable dose was given followed by 10 mg dipyridamole intravenously and a second injection of the same dose of adenosine. Heart rate and atrioventricular blocks were recorded by electrocardiography. One minute after each dose of adenosine the chest pain was scored. The maximum tolerable dose of adenosine ranged from 10.6 to 37.1 mg. All subjects experienced uneasy central chest pain provoking anxiety. The pain radiated to the shoulders, ulnar aspect of the arms, epigastric area, back, and into the throat. The pain began about 20 seconds after the injection and lasted 10-15 seconds. Increasing the dose of adenosine increased the intensity of the pain. Administration of aminophylline reduced the pain significantly. Second degree heart block was recorded in five of the six subjects during the time that the pain was experienced. After aminophylline no block was observed. Dipyridamole increased the intensity of pain. The duration of second degree heart block increased in four of the subjects, and in two of these third degree heart block occurred. These findings suggest that adenosine released from the myocardium during ischaemia induces angina pectoris by stimulating theophylline sensitive receptors. PMID:3089465

  16. Bradykinin and adenosine receptors mediate desflurane induced postconditioning in human myocardium: role of reactive oxygen species

    Gérard Jean-Louis

    2010-07-01

    Full Text Available Abstract Background Desflurane during early reperfusion has been shown to postcondition human myocardium, in vitro. We investigated the role of adenosine and bradykinin receptors, and generation of radical oxygen species in desflurane-induced postconditioning in human myocardium. Methods We recorded isometric contraction of human right atrial trabeculae hanged in an oxygenated Tyrode's solution (34 degrees Celsius, stimulation frequency 1 Hz. After a 30-min hypoxic period, desflurane 6% was administered during the first 5 min of reoxygenation. Desflurane was administered alone or with pretreatment of N-mercaptopropionylglycine, a reactive oxygen species scavenger, 8-(p-Sulfophenyltheophylline, an adenosine receptor antagonist, HOE140, a selective B2 bradykinin receptor antagonist. In separate groups, adenosine and bradykinin were administered during the first minutes of reoxygenation alone or in presence of N-mercaptopropionylglycine. The force of contraction of trabeculae was recorded continuously. Developed force at the end of a 60-min reoxygenation period was compared (mean ± standard deviation between the groups by a variance analysis and post hoc test. Results Desflurane 6% (84 ± 6% of baseline enhanced the recovery of force after 60-min of reoxygenation as compared to control group (51 ± 8% of baseline, P N-mercaptopropionylglycine (54 ± 3% of baseline, 8-(p-Sulfophenyltheophylline (62 ± 9% of baseline, HOE140 (58 ± 6% of baseline abolished desflurane-induced postconditioning. Adenosine (80 ± 9% of baseline and bradykinin (83 ± 4% of baseline induced postconditioning (P vs control, N-mercaptopropionylglycine abolished the beneficial effects of adenosine and bradykinin (54 ± 8 and 58 ± 5% of baseline, respectively. Conclusions In vitro, desflurane-induced postconditioning depends on reactive oxygen species production, activation of adenosine and bradykinin B2 receptors. And, the cardioprotective effect of adenosine and bradykinin

  17. Three minute versus six minute adenosine infusion in myocardial perfusion scintigraphy

    Pharmacological stress imaging techniques are used widely in clinical nuclear cardiology for evaluation of ischemic heart disease. Adenosine is often used but is expensive and causes significant side effects .The aim of this retrospective review was to study the tolerance and efficacy, of adenosine infusion of a 3 minute (min) versus the conventional 6 min stress protocol and to assess the cost efficiency of the 3 min protocol. Three hundred thirty one patients had myocardial scintigraphy using adenosine as a stressing agent. Blood pressure, heart rate and ECG were recorded at baseline and during the test. Symptoms (flushing, headache, chest pain, dyspnoea, neck pain) were recorded throughout the adenosine infusion. All the patients had had either 6 min or 3 min adenosine infusion at 140 mg/kg per minute. 169 of them had side effects. Flushing (32% at 3 min vs 50 % at 6 min, p<0.05), headache (11.5% at 3 min vs 7 % at 6 min p-not significant-ns), chest pain (8% at 3 min vs 13 % at 6 min, ns), dyspnoea (7% at 3 min vs %10 at 6 min, ns), ECG changes (10% at 3 min vs 28% at 6 min, p<0.05), neck pain (4.5% at 3 min vs 9% at 6 min, ns), abdominal discomfort (3% at 3 min vs 3% at 6 min, ns) and fall in blood pressure (6% at 3 min vs 8.5% at 6 min, ns). The change in heart rate was not significant with either protocol. The 6 min and 3 min infusions of adenosine had similar accuracy (73% vs 70%) for the detection of coronary artery disease. The patients tolerated the 3 min protocol better with only 40% of the patients having minimal side effects compared with 60% for the 6 mon protocol. The 3 min protocol is also cost effective as it uses less adenosine and therefore reduces total costs by 40 US$ per patient. (author)

  18. Structural basis of the substrate specificity of Bacillus cereus adenosine phosphorylase

    Dessanti, Paola [Cornell University, Ithaca, NY 14853-1301 (United States); Università di Sassari, (Italy); Zhang, Yang [Cornell University, Ithaca, NY 14853-1301 (United States); Allegrini, Simone [Università di Sassari, (Italy); Tozzi, Maria Grazia [Università di Pisa, (Italy); Sgarrella, Francesco [Università di Sassari, (Italy); Ealick, Steven E., E-mail: see3@cornell.edu [Cornell University, Ithaca, NY 14853-1301 (United States)

    2012-03-01

    Adenosine phosphorylase from B. cereus shows a strong preference for adenosine over other 6-oxopurine nucleosides. Mutation of Asp204 to asparagine reduces the efficiency of adenosine cleavage but does not affect inosine cleavage, effectively reversing the substrate specificity. The structures of D204N complexes explain these observations. Purine nucleoside phosphorylases catalyze the phosphorolytic cleavage of the glycosidic bond of purine (2′-deoxy)nucleosides, generating the corresponding free base and (2′-deoxy)ribose 1-phosphate. Two classes of PNPs have been identified: homotrimers specific for 6-oxopurines and homohexamers that accept both 6-oxopurines and 6-aminopurines. Bacillus cereus adenosine phosphorylase (AdoP) is a hexameric PNP; however, it is highly specific for 6-aminopurines. To investigate the structural basis for the unique substrate specificity of AdoP, the active-site mutant D204N was prepared and kinetically characterized and the structures of the wild-type protein and the D204N mutant complexed with adenosine and sulfate or with inosine and sulfate were determined at high resolution (1.2–1.4 Å). AdoP interacts directly with the preferred substrate through a hydrogen-bond donation from the catalytically important residue Asp204 to N7 of the purine base. Comparison with Escherichia coli PNP revealed a more optimal orientation of Asp204 towards N7 of adenosine and a more closed active site. When inosine is bound, two water molecules are interposed between Asp204 and the N7 and O6 atoms of the nucleoside, thus allowing the enzyme to find alternative but less efficient ways to stabilize the transition state. The mutation of Asp204 to asparagine led to a significant decrease in catalytic efficiency for adenosine without affecting the efficiency of inosine cleavage.

  19. Structural basis of the substrate specificity of Bacillus cereus adenosine phosphorylase

    Adenosine phosphorylase from B. cereus shows a strong preference for adenosine over other 6-oxopurine nucleosides. Mutation of Asp204 to asparagine reduces the efficiency of adenosine cleavage but does not affect inosine cleavage, effectively reversing the substrate specificity. The structures of D204N complexes explain these observations. Purine nucleoside phosphorylases catalyze the phosphorolytic cleavage of the glycosidic bond of purine (2′-deoxy)nucleosides, generating the corresponding free base and (2′-deoxy)ribose 1-phosphate. Two classes of PNPs have been identified: homotrimers specific for 6-oxopurines and homohexamers that accept both 6-oxopurines and 6-aminopurines. Bacillus cereus adenosine phosphorylase (AdoP) is a hexameric PNP; however, it is highly specific for 6-aminopurines. To investigate the structural basis for the unique substrate specificity of AdoP, the active-site mutant D204N was prepared and kinetically characterized and the structures of the wild-type protein and the D204N mutant complexed with adenosine and sulfate or with inosine and sulfate were determined at high resolution (1.2–1.4 Å). AdoP interacts directly with the preferred substrate through a hydrogen-bond donation from the catalytically important residue Asp204 to N7 of the purine base. Comparison with Escherichia coli PNP revealed a more optimal orientation of Asp204 towards N7 of adenosine and a more closed active site. When inosine is bound, two water molecules are interposed between Asp204 and the N7 and O6 atoms of the nucleoside, thus allowing the enzyme to find alternative but less efficient ways to stabilize the transition state. The mutation of Asp204 to asparagine led to a significant decrease in catalytic efficiency for adenosine without affecting the efficiency of inosine cleavage

  20. Impairment of ATP hydrolysis decreases adenosine A1 receptor tonus favoring cholinergic nerve hyperactivity in the obstructed human urinary bladder.

    Silva-Ramos, M; Silva, I; Faria, M; Magalhães-Cardoso, M T; Correia, J; Ferreirinha, F; Correia-de-Sá, P

    2015-12-01

    This study was designed to investigate whether reduced adenosine formation linked to deficits in extracellular ATP hydrolysis by NTPDases contributes to detrusor neuromodulatory changes associated with bladder outlet obstruction in men with benign prostatic hyperplasia (BPH). The kinetics of ATP catabolism and adenosine formation as well as the role of P1 receptor agonists on muscle tension and nerve-evoked [(3)H]ACh release were evaluated in mucosal-denuded detrusor strips from BPH patients (n = 31) and control organ donors (n = 23). The neurogenic release of ATP and [(3)H]ACh was higher (P bladders. Relaxation of detrusor contractions induced by acetylcholine required 30-fold higher concentrations of adenosine. Despite VAChT-positive cholinergic nerves exhibiting higher A(1) immunoreactivity in BPH bladders, the endogenous adenosine tonus revealed by adenosine deaminase is missing. Restoration of A1 inhibition was achieved by favoring (1) ATP hydrolysis with apyrase (2 U mL(-1)) or (2) extracellular adenosine accumulation with dipyridamole or EHNA, as these drugs inhibit adenosine uptake and deamination, respectively. In conclusion, reduced ATP hydrolysis leads to deficient adenosine formation and A(1) receptor-mediated inhibition of cholinergic nerve activity in the obstructed human bladder. Thus, we propose that pharmacological manipulation of endogenous adenosine levels and/or A(1) receptor activation might be useful to control bladder overactivity in BPH patients. PMID:26521170

  1. Adenosine triphosphate inhibits melatonin synthesis in the rat pineal gland.

    Souza-Teodoro, Luis Henrique; Dargenio-Garcia, Letícia; Petrilli-Lapa, Camila Lopes; Souza, Ewerton da Silva; Fernandes, Pedro A C M; Markus, Regina P; Ferreira, Zulma S

    2016-03-01

    Adenosine triphosphate (ATP) is released onto the pinealocyte, along with noradrenaline, from sympathetic neurons and triggers P2Y1 receptors that enhance β-adrenergic-induced N-acetylserotonin (NAS) synthesis. Nevertheless, the biotransformation of NAS into melatonin, which occurs due to the subsequent methylation by acetylserotonin O-methyltransferase (ASMT; EC 2.1.1.4), has not yet been evaluated in the presence of purinergic stimulation. We therefore evaluated the effects of purinergic signaling on melatonin synthesis induced by β-adrenergic stimulation. ATP increased NAS levels, but, surprisingly, inhibited melatonin synthesis in an inverse, concentration-dependent manner. Our results demonstrate that enhanced NAS levels, which depend on phospholipase C (PLC) activity (but not the induction of gene transcription), are a post-translational effect. By contrast, melatonin reduction is related to an ASMT inhibition of expression at both the gene transcription and protein levels. These results were independent of nuclear factor-kappa B (NF-kB) translocation. Neither the P2Y1 receptor activation nor the PLC-mediated pathway was involved in the decrease in melatonin, indicating that ATP regulates pineal metabolism through different mechanisms. Taken together, our data demonstrate that purinergic signaling differentially modulates NAS and melatonin synthesis and point to a regulatory role for ATP as a cotransmitter in the control of ASMT, the rate-limiting enzyme in melatonin synthesis. The endogenous production of melatonin regulates defense responses; therefore, understanding the mechanisms involving ASMT regulation might provide novel insights into the development and progression of neurological disorders since melatonin presents anti-inflammatory, neuroprotective, and neurogenic effects. PMID:26732366

  2. Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems. PMID:27295623

  3. The adenosine A2B receptor is involved in anion secretion in human pancreatic duct Capan-1 epithelial cells.

    Hayashi, M; Inagaki, A; Novak, I; Matsuda, H

    2016-07-01

    Adenosine modulates a wide variety of biological processes via adenosine receptors. In the exocrine pancreas, adenosine regulates transepithelial anion secretion in duct cells and is considered to play a role in acini-to-duct signaling. To identify the functional adenosine receptors and Cl(-) channels important for anion secretion, we herein performed experiments on Capan-1, a human pancreatic duct cell line, using open-circuit Ussing chamber and gramicidin-perforated patch-clamp techniques. The luminal addition of adenosine increased the negative transepithelial potential difference (V te) in Capan-1 monolayers with a half-maximal effective concentration value of approximately 10 μM, which corresponded to the value obtained on whole-cell Cl(-) currents in Capan-1 single cells. The effects of adenosine on V te, an equivalent short-circuit current (I sc), and whole-cell Cl(-) currents were inhibited by CFTRinh-172, a cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel inhibitor. The adenosine A2B receptor agonist, BAY 60-6583, increased I sc and whole-cell Cl(-) currents through CFTR Cl(-) channels, whereas the A2A receptor agonist, CGS 21680, had negligible effects. The A2B receptor antagonist, PSB 603, inhibited the response of I sc to adenosine. Immunohistochemical analysis showed that the A2A and A2B receptors colocalized with Ezrin in the luminal membranes of Capan-1 monolayers and in rat pancreatic ducts. Adenosine elicited the whole-cell Cl(-) currents in guinea pig duct cells. These results demonstrate that luminal adenosine regulates anion secretion by activating CFTR Cl(-) channels via adenosine A2B receptors on the luminal membranes of Capan-1 cells. The present study endorses that purinergic signaling is important in the regulation of pancreatic secretion. PMID:26965147

  4. Adenosine concentrations in the interstitium of resting and contracting human skeletal muscle

    Hellsten, Ylva; Maclean, D.; Rådegran, G.;

    1998-01-01

    effect remain unanswered. METHODS AND RESULTS: The interstitial adenosine concentration was determined in the vastus lateralis muscle of healthy humans via dialysis probes inserted in the muscle. The probes were perfused with buffer, and the dialysate samples were collected at rest and during graded knee...... extensor exercise. At rest, the interstitial concentration of adenosine was 220+/-100 nmol/L and femoral arterial blood flow (FaBF) was 0.19+/-0.02 L/min. When the subjects exercised lightly, at a work rate of 10 W, there was a markedly higher (1140+/-540 nmol/L; P... and demonstrates that adenosine and its precursors increase in the exercising muscle interstitium, at a rate associated with intensity of muscle contraction and the magnitude of muscle blood flow....

  5. Circadian rhythm in adenosine A1 receptor of mouse cerebral cortex

    In order to investigate diurnal variation in adenosine A1 receptors binding parameters, Bmax and Kd values of specifically bound N6-cyclohexyl-[3H]adenosine were determined in the cerebral cortex of mice that had been housed under controlled light-dark cycles for 4 weeks. Significant differences were found for Bmax values measured at 3-hr intervals across a 24-h period, with low Bmax values during the light period and high Bmax values during the dark period. The amplitude between 03.00 and 18.00 hr was 33%. No substantial rhythm was found in the Kd values. It is suggested that the changes in the density of A1 receptors could reflect a physiologically-relevant mechanism by which adenosine exerts its modulatory role in the central nervous system

  6. The Three Possible 2-(Pyrenylethynyl) Adenosines: Rotameric Energy Barriers Govern the Photodynamics of These Structural Isomers.

    Reuss, Andreas J; Grünewald, Christian; Braun, Markus; Engels, Joachim W; Wachtveitl, Josef

    2016-05-01

    This article presents a comprehensive study of the photophysics of 2-(2-pyrenylethynyl) adenosine and 2-(4-pyrenylethynyl) adenosine, which are structural isomers of the well-established fluorescent RNA label 2-(1-pyrenylethynyl) adenosine. We performed steady-state and ultrafast transient absorption spectroscopy studies along with time-resolved fluorescence emission experiments in different solvents to work out the interplay of locally excited and charge-transfer states. We found the ultrafast photodynamics to be crucial for the fluorescence decay behavior, which extends up to tens of nanoseconds and is partially multi-exponential. These features in the ultrafast dynamics are indicative of the rotational energy barriers in the first excited state. PMID:26635201

  7. Magnetically assisted fluorescence ratiometric assays for adenosine deaminase using water-soluble conjusated polymers

    HE Fang; YU MingHui; WANG Shu

    2009-01-01

    A magnetically assisted fluorescence ratiometric technique has been developed for adenosine deami-nase assays with high sensitivity using water-soluble cationic conjugated polymers (CCPs).The assay contains three elements:a biotin-labeled aptamer of adenosine (biotin-aptamer),a signaling probe single-stranded DNA-tagged fiuorescein at terminus (ssDNA-FI) and a CCP.The specific binding of adenosine to biotin-aptamer makes biotin-aptamer and ssDNA-FI unhybridized,and the ssDNA-FI is washed out after streptavidin-coated magnetic beads are added and separated from the assay solution under magnetic field.In this case,after the addition of CCP to the magnetic beads solution,the fluo-rescence resonance energy transfer (FRET) from CCP to fluorescein is inefficient.Upon adding adenosine deaminase,the adenosine is converted into inosine,and the biotin-aptamer is hybridized with ssDNA-FI to form doubled stranded DNA (biotin-dsDNA-FI).The ssONA-FI is attached to the mag-netic beads at the separation step,and the addition of CCP to the magnetic beads solution leads to efficient FRET from CCP to fluorescein.Thus the adenosine deaminase activity can be monitored by fluorescence spectra in view of the intensity decrease of CCP emission or the increase of fluorescein emission in aqueous solutions.The assay integrates surface-functionalized magnetic particles with significant amplification of detection signal of water-soluble cationic conjugated polymers.

  8. Increase of adenosine plasma levels after oral trimetazidine: a pharmacological preconditioning?

    Blardi, Patrizia; de Lalla, Arianna; Volpi, Luciana; Auteri, Alberto; Di Perri, Tullio

    2002-01-01

    Trimetazidine (1-[2,3,4-trimethoxybenzyl] piperazine) (TMZ) is a cellular anti-ischemic agent able to prevent intracellular ATP decrease, limit intracellular acidosis, protect against oxygen-free radical-induced toxicity and inhibit neutrophil infiltration. However, its definitive mechanism of action had not been identified. Recent studies showed the existence of an endogenous mechanism of cellular protection against ischemia, defined as 'ischemic preconditioning'. This mechanism was related mainly to cellular liberation of adenosine, a nucleoside with protective effects in myocardial ischemia. Since TMZ acts by increasing cell tolerance to ischemia and adenosine is the mediator of ischemic preconditioning, in this study we investigated a possible interaction between TMZ and adenosine. Two groups of patients affected by angina pectoris, were admitted to the study. They received a single oral dose of TMZ. One group was treated, during different sessions, with TMZ 10 and 20 mg, the other group with TMZ 40 and 80 mg. After a 3 day wash-out from drug administration, each group received a placebo. Blood samples were collected at baseline (time 0) and 1, 2, 3, 4, 6, 8 h after drug administration, in order to detect plasma levels of adenosine by a high-performance liquid chromatography method. We observed that the administration of TMZ at doses of 10, 20, 40 and 80 mg induced an increase of adenosine plasma levels of 19, 50, 62 and 62%, respectively. We hypothesized that the activity of TMZ could depend, at least in part, on adenosine mediation and this interaction opens a new interpretation of the drug antischemic effect. PMID:11820865

  9. 2'-O methylation of internal adenosine by flavivirus NS5 methyltransferase.

    Hongping Dong

    Full Text Available RNA modification plays an important role in modulating host-pathogen interaction. Flavivirus NS5 protein encodes N-7 and 2'-O methyltransferase activities that are required for the formation of 5' type I cap (m(7GpppAm of viral RNA genome. Here we reported, for the first time, that flavivirus NS5 has a novel internal RNA methylation activity. Recombinant NS5 proteins of West Nile virus and Dengue virus (serotype 4; DENV-4 specifically methylates polyA, but not polyG, polyC, or polyU, indicating that the methylation occurs at adenosine residue. RNAs with internal adenosines substituted with 2'-O-methyladenosines are not active substrates for internal methylation, whereas RNAs with adenosines substituted with N⁶-methyladenosines can be efficiently methylated, suggesting that the internal methylation occurs at the 2'-OH position of adenosine. Mass spectroscopic analysis further demonstrated that the internal methylation product is 2'-O-methyladenosine. Importantly, genomic RNA purified from DENV virion contains 2'-O-methyladenosine. The 2'-O methylation of internal adenosine does not require specific RNA sequence since recombinant methyltransferase of DENV-4 can efficiently methylate RNAs spanning different regions of viral genome, host ribosomal RNAs, and polyA. Structure-based mutagenesis results indicate that K61-D146-K181-E217 tetrad of DENV-4 methyltransferase forms the active site of internal methylation activity; in addition, distinct residues within the methyl donor (S-adenosyl-L-methionine pocket, GTP pocket, and RNA-binding site are critical for the internal methylation activity. Functional analysis using flavivirus replicon and genome-length RNAs showed that internal methylation attenuated viral RNA translation and replication. Polymerase assay revealed that internal 2'-O-methyladenosine reduces the efficiency of RNA elongation. Collectively, our results demonstrate that flavivirus NS5 performs 2'-O methylation of internal adenosine of

  10. Adenosine receptor antagonists alter the stability of human epileptic GABAA receptors

    Roseti, Cristina; Martinello, Katiuscia; Fucile, Sergio; Piccari, Vanessa; Mascia, Addolorata; Di Gennaro, Giancarlo; Quarato, Pier Paolo; Manfredi, Mario; Esposito, Vincenzo; Cantore, Gianpaolo; Arcella, Antonella; Simonato, Michele; Fredholm, Bertil B.; Limatola, Cristina; Miledi, Ricardo; Eusebi, Fabrizio

    2008-01-01

    We examined how the endogenous anticonvulsant adenosine might influence γ-aminobutyric acid type A (GABAA) receptor stability and which adenosine receptors (ARs) were involved. Upon repetitive activation (GABA 500 μM), GABAA receptors, microtransplanted into Xenopus oocytes from neurosurgically resected epileptic human nervous tissues, exhibited an obvious GABAA-current (IGABA) run-down, which was consistently and significantly reduced by treatment with the nonselective adenosine receptor antagonist CGS15943 (100 nM) or with adenosine deaminase (ADA) (1 units/ml), that inactivates adenosine. It was also found that selective antagonists of A2B (MRS1706, 10 nM) or A3 (MRS1334, 30 nM) receptors reduced IGABA run-down, whereas treatment with the specific A1 receptor antagonist DPCPX (10 nM) was ineffective. The selective A2A receptor antagonist SCH58261 (10 nM) reduced or potentiated IGABA run-down in ≈40% and ≈20% of tested oocytes, respectively. The ADA-resistant, AR agonist 2-chloroadenosine (2-CA) (10 μM) potentiated IGABA run-down but only in ≈20% of tested oocytes. CGS15943 administration again decreased IGABA run-down in patch-clamped neurons from either human or rat neocortex slices. IGABA run-down in pyramidal neurons was equivalent in A1 receptor-deficient and wt neurons but much larger in neurons from A2A receptor-deficient mice, indicating that, in mouse cortex, GABAA-receptor stability is tonically influenced by A2A but not by A1 receptors. IGABA run-down from wt mice was not affected by 2-CA, suggesting maximal ARs activity by endogenous adenosine. Our findings strongly suggest that cortical A2–A3 receptors alter the stability of GABAA receptors, which could offer therapeutic opportunities. PMID:18809912

  11. Adenosine transport systems on dissociated brain cells from mouse, guinea-pig, and rat

    Johnston, M.E.; Geiger, J.D. (Univ. of Manitoba, Winnipeg (Canada))

    1990-09-01

    The kinetics and sodium dependence of adenosine transport were determined using an inhibitor-stop method on dissociated cell body preparations obtained from mouse, guinea-pig and rat brain. Transport affinity (KT) values for the high affinity adenosine transport systems KT(H) were significantly different between these three species; mean +/- SEM values were 0.34 +/- 0.1 in mouse, 0.9 +/- 0.2 in rat, and 1.5 +/- 0.5 microM in guinea-pig. The KT values for the low affinity transport system KT(L) were not different between the three species. Brain cells from rat displayed a significantly greater maximal capacity to accumulate (3H)adenosine (Vmax) than did mouse or guinea-pig for the high affinity system, or than did mouse for the low affinity system. When sodium chloride was replaced in the transport medium with choline chloride, the KT(H) values for guinea-pig and rat were both increased by approximately 100%; only in rat did the change reach statistical significance. The sodium-dependence of adenosine transport in mouse brain was clearly absent. The differences between KT(H) values in mouse and those in guinea-pig or rat were accentuated in the absence of sodium. The differences in kinetic values, ionic requirements, and pharmacological characteristics between adenosine transporters in CNS tissues of mouse, guinea-pig and rat may help account for some of the variability noted among species in terms of their physiological responses to adenosine.

  12. Lack of effect of adenosine on the function of rodent osteoblasts and osteoclasts in vitro.

    Hajjawi, Mark O R; Patel, Jessal J; Corcelli, Michelangelo; Arnett, Timothy R; Orriss, Isabel R

    2016-06-01

    Extracellular ATP, signalling through P2 receptors, exerts well-documented effects on bone cells, inhibiting mineral deposition by osteoblasts and stimulating the formation and resorptive activity of osteoclasts. The aims of this study were to determine the potential osteotropic effects of adenosine, the hydrolysis product of ATP, on primary bone cells in vitro. We determined the effect of exogenous adenosine on (1) the growth, alkaline phosphatase (TNAP) activity and bone-forming ability of osteoblasts derived from the calvariae of neonatal rats and mice and the marrow of juvenile rats and (2) the formation and resorptive activity of osteoclasts from juvenile mouse marrow. Reverse transcription polymerase chain reaction (RT-PCR) analysis showed marked differences in the expression of P1 receptors in osteoblasts from different sources. Whilst mRNA for the A1 and A2B receptors was expressed by all primary osteoblasts, A2A receptor expression was limited to rat bone marrow and mouse calvarial osteoblasts and the A3 receptor to rat bone marrow osteoblasts. We found that adenosine had no detectable effects on cell growth, TNAP activity or bone formation by rodent osteoblasts in vitro. The analogue 2-chloroadenosine, which is hydrolysed more slowly than adenosine, had no effects on rat or mouse calvarial osteoblasts but increased TNAP activity and bone formation by rat bone marrow osteoblasts by 30-50 % at a concentration of 1 μM. Osteoclasts were found to express the A2A, A2B and A3 receptors; however, neither adenosine (≤100 μM) nor 2-chloroadenosine (≤10 μM) had any effect on the formation or resorptive activity of mouse osteoclasts in vitro. These results suggest that adenosine, unlike ATP, is not a major signalling molecule in the bone. PMID:26861849

  13. Interleukin-6-type cytokines in neuroprotection and neuromodulation: Oncostatin M, but not leukemia inhibitory factor, requires neuronal Adenosine A1 receptor function

    Moidunny, S.; Dias, R.; Van Calker, D.; Boddeke, H.; Sebastiao, A.; Biber, K.

    2010-01-01

    Objective: Adenosine is a neuromodulator in the central nervous system exhibiting anticonvulsive, neuroprotective and sedating/sleep regulating properties. A pathophysiological importance of adenosine in various neuropsychiatric diseases (e.g. epilepsy, neurodegenerative disorders, apoplexia and moo

  14. Plasma concentrations of the cyclic nucleotides, adenosine 3',5'-monophosphate and guanosine 3'.5'-monophosphate, in healthy adults treated with theophylline

    Fenger, M; Eriksen, P B; Andersen, O; Nielsen, M K; Knudsen, P J

    1982-01-01

    Plasma concentrations of cyclic adenosine monophosphate and cyclic guanosine monophosphate were measured in 10 health adults before, during and after periods of theophylline administration. Cyclic adenosine monophosphate concentrations did not change significantly, but cyclic guanosine monophosph...

  15. Molecular expression of adenosine receptors in OVCAR-3, Caov-4 and SKOV-3 human ovarian cancer cell lines.

    Hajiahmadi, S; Panjehpour, M; Aghaei, M; Mousavi, S

    2015-01-01

    Adenosine receptors (A1, A2a, A2b and A3) have several physiological and pathological roles in cancer cell lines. The present study was carried out to evaluate the mRNA and protein expression profile and functional role of adenosine receptors in OVCAR-3, Caov-4 and SKOV-3 ovarian cancer cell lines. The levels of mRNA and protein expression of A1, A2a, A2b and A3 adenosine receptors in the ovarian cancer cell lines were measured by Real-time PCR and western blotting. The functional roles of adenosine receptors were investigated through measurement of cAMP levels after agonist treatment. The mRNA and protein of all adenosine receptors subtypes were expressed in the ovarian cancer cell lines. Our findings demonstrated that A2b and A3 had the most mRNA and protein expression. Moreover, cAMP assay confirmed the functional role of A2b and A3 adenosine receptors. This findings demonstrated that A2b and A3 subtypes are most important adenosine receptors in humn ovarian cancer cell lines. This information provide a strong possibility into the relationship of A2b and A3 adenosine receptor and ovarian cancer. PMID:26430456

  16. Molecular expression of adenosine receptors in OVCAR-3, Caov-4 and SKOV-3 human ovarian cancer cell lines

    Hajiahmadi, S.; Panjehpour, M.; Aghaei, M.; Mousavi, S.

    2015-01-01

    Adenosine receptors (A1, A2a, A2b and A3) have several physiological and pathological roles in cancer cell lines. The present study was carried out to evaluate the mRNA and protein expression profile and functional role of adenosine receptors in OVCAR-3, Caov-4 and SKOV-3 ovarian cancer cell lines. The levels of mRNA and protein expression of A1, A2a, A2b and A3 adenosine receptors in the ovarian cancer cell lines were measured by Real-time PCR and western blotting. The functional roles of adenosine receptors were investigated through measurement of cAMP levels after agonist treatment. The mRNA and protein of all adenosine receptors subtypes were expressed in the ovarian cancer cell lines. Our findings demonstrated that A2b and A3 had the most mRNA and protein expression. Moreover, cAMP assay confirmed the functional role of A2b and A3 adenosine receptors. This findings demonstrated that A2b and A3 subtypes are most important adenosine receptors in humn ovarian cancer cell lines. This information provide a strong possibility into the relationship of A2b and A3 adenosine receptor and ovarian cancer. PMID:26430456

  17. Adenosine inhibits neutrophil vascular endothelial growth factor release and transendothelial migration via A2B receptor activation.

    Wakai, A

    2012-02-03

    The effects of adenosine on neutrophil (polymorphonuclear neutrophils; PMN)-directed changes in vascular permeability are poorly characterized. This study investigated whether adenosine modulates activated PMN vascular endothelial growth factor (vascular permeability factor; VEGF) release and transendothelial migration. PMN activated with tumour necrosis factor-alpha (TNF-alpha, 10 ng\\/mL) were incubated with adenosine and its receptor-specific analogues. Culture supernatants were assayed for VEGF. PMN transendothelial migration across human umbilical vein endothelial cell (HUVEC) monolayers was assessed in vitro. Adhesion molecule receptor expression was assessed flow cytometrically. Adenosine and some of its receptor-specific analogues dose-dependently inhibited activated PMN VEGF release. The rank order of potency was consistent with the affinity profile of human A2B receptors. The inhibitory effect of adenosine was reversed by 3,7-dimethyl-1-propargylxanthine, an A2 receptor antagonist. Adenosine (100 microM) or the A2B receptor agonist 5\\'-N-ethylcarboxamidoadenosine (NECA, 100 microM) significantly reduced PMN transendothelial migration. However, expression of activated PMN beta2 integrins and HUVEC ICAM-1 were not significantly altered by adenosine or NECA. Adenosine attenuates human PMN VEGF release and transendothelial migration via the A2B receptor. This provides a novel target for the modulation of PMN-directed vascular hyperpermeability in conditions such as the capillary leak syndrome.

  18. Comparison of adenosine and treadmill exercise thallium-201 stress tests for the detection of coronary artery disease.

    Abe, S; Takeishi, Y; Chiba, J; Ikeda, K; Tomoike, H

    1993-12-01

    To determine the clinical usefulness of adenosine Tl-201 imaging for the evaluation of coronary artery disease, 22 patients with suspected coronary artery disease who underwent adenosine and exercise Tl-201 single photon emission computed tomography (SPECT) were studied. The peak levels of heart rate (83 vs 123 bpm, p pressure products (10220 vs 20410 bpm x mmHg, p < 0.001) were markedly smaller during adenosine infusion than during exercise. Segmental agreements between adenosine and exercise tests were 90% (218 of 242 segments) regarding the presence of perfusion defects and 89% (215 of 242 segments) regarding the presence of redistribution. Regional Tl-201 uptake (r = 0.85, p < 0.001) and the extent (r = 0.75, p < 0.001) and intensity (r = 0.83, p < 0.001) of Tl-201 defects during adenosine testing were closely correlated with those of exercise testing. Adenosine and exercise tests showed similar sensitivities for the identification of individual coronary stenosis (85% vs 78%). However, in patients who were unable to perform adequate exercise (maximal heart rate < 120 bpm), the sensitivity of adenosine imaging tended to be higher than that of exercise imaging (92% vs 69%, p = 0.07). Adenosine Tl-201 imaging is an alternative to the exercise test for assessing the severity and loci of coronary artery disease, especially in patients who are unable to perform adequate physical exercise. PMID:8283603

  19. NTS adenosine A2a receptors inhibit the cardiopulmonary chemoreflex control of regional sympathetic outputs via a GABAergic mechanism.

    Minic, Zeljka; O'Leary, Donal S; Scislo, Tadeusz J

    2015-07-01

    Adenosine is a powerful central neuromodulator acting via opposing A1 (inhibitor) and A2a (activator) receptors. However, in the nucleus of the solitary tract (NTS), both adenosine receptor subtypes attenuate cardiopulmonary chemoreflex (CCR) sympathoinhibition of renal, adrenal, and lumbar sympathetic nerve activity and attenuate reflex decreases in arterial pressure and heart rate. Adenosine A1 receptors inhibit glutamatergic transmission in the CCR pathway, whereas adenosine A2a receptors most likely facilitate release of an unknown inhibitory neurotransmitter, which, in turn, inhibits the CCR. We hypothesized that adenosine A2a receptors inhibit the CCR via facilitation of GABA release in the NTS. In urethane-chloralose-anesthetized rats (n = 51), we compared regional sympathetic responses evoked by stimulation of the CCR with right atrial injections of the 5-HT3 receptor agonist phenylbiguanide (1-8 μg/kg) before and after selective stimulation of NTS adenosine A2a receptors [microinjections into the NTS of CGS-21680 (20 pmol/50 nl)] preceded by blockade of GABAA or GABAB receptors in the NTS [bicuculline (10 pmol/100 nl) or SCH-50911 (1 nmol/100 nl)]. Blockade of GABAA receptors virtually abolished adenosine A2a receptor-mediated inhibition of the CCR. GABAB receptors had much weaker but significant effects. These effects were similar for the different sympathetic outputs. We conclude that stimulation of NTS adenosine A2a receptors inhibits CCR-evoked hemodynamic and regional sympathetic reflex responses via a GABA-ergic mechanism. PMID:25910812

  20. Regulation of photoreceptor gap junction phosphorylation by adenosine in zebrafish retina.

    Li, Hongyan; Chuang, Alice Z; O'Brien, John

    2014-05-01

    Electrical coupling of photoreceptors through gap junctions suppresses voltage noise, routes rod signals into cone pathways, expands the dynamic range of rod photoreceptors in high scotopic and mesopic illumination, and improves detection of contrast and small stimuli. In essentially all vertebrates, connexin 35/36 (gene homologs Cx36 in mammals, Cx35 in other vertebrates) is the major gap junction protein observed in photoreceptors, mediating rod-cone, cone-cone, and possibly rod-rod communication. Photoreceptor coupling is dynamically controlled by the day/night cycle and light/dark adaptation, and is directly correlated with phosphorylation of Cx35/36 at two sites, serine110 and serine 276/293 (homologous sites in teleost fish and mammals, respectively). Activity of protein kinase A (PKA) plays a key role during this process. Previous studies have shown that activation of dopamine D4 receptors on photoreceptors inhibits adenylyl cyclase, down-regulates cAMP and PKA activity, and leads to photoreceptor uncoupling, imposing the daytime/light condition. In this study, we explored the role of adenosine, a nighttime signal with a high extracellular concentration at night and a low concentration in the day, in regulating photoreceptor coupling by examining photoreceptor Cx35 phosphorylation in zebrafish retina. Adenosine enhanced photoreceptor Cx35 phosphorylation in daytime, but with a complex dose-response curve. Selective pharmacological manipulations revealed that adenosine A2a receptors provide a potent positive drive to phosphorylate photoreceptor Cx35 under the influence of endogenous adenosine at night. A2a receptors can be activated in the daytime as well by micromolar exogenous adenosine. However, the higher affinity adenosine A1 receptors are also present and have an antagonistic though less potent effect. Thus, the nighttime/darkness signal adenosine provides a net positive drive on Cx35 phosphorylation at night, working in opposition to dopamine to

  1. Adenosine as a signaling molecule in the retina: biochemical and developmental aspects

    ROBERTO PAES-DE-CARVALHO

    2002-09-01

    Full Text Available The nucleoside adenosine plays an important role as a neurotransmitter or neuromodulator in the central nervous system, including the retina. In the present paper we review compelling evidence showing that adenosine is a signaling molecule in the developing retina. In the chick retina, adenosine transporters are present since early stages of development before the appearance of adenosine A1 receptors modulating dopamine-dependent adenylate cyclase activity or A2 receptors that directly activate the enzyme. Experiments using retinal cell cultures revealed that adenosine is taken up by specific cell populations that when stimulated by depolarization or neurotransmitters such as dopamine or glutamate, release the nucleoside through calcium-dependent transporter-mediated mechanisms. The presence of adenosine in the extracellular medium and the long-term activation of adenosine receptors is able to regulate the survival of retinal neurons and blocks glutamate excitoxicity. Thus, adenosine besides working as a neurotransmitter or neuromodulator in the mature retina, is considered as an important signaling molecule during retinal development having important functions such as regulation of neuronal survival and differentiation.O nucleosídeo adenosina apresenta um importante papel como neurotransmissor ou neuromodulador no sistema nervoso central, inclusive na retina. Neste artigo apresentamos uma revisão das evidências que mostram que a adenosina é uma molécula sinalizadora na retina em desenvolvimento. Na retina de pinto, transportadores de adenosina estão presentes desde estágios precoces do desenvolvimento, antes do aparecimento dos receptores A1 que modulam a atividade adenilato ciclase dependente de dopamina ou dos receptores A2 que ativam diretamente a enzima. Experimentos usando culturas de células de retina revelaram que a adenosina é captada por populações celulares específicas que, quando estimuladas por despolarização ou por

  2. Pharmacological Characterization of Novel A3 Adenosine Receptor-selective Antagonists

    Jacobson, Kenneth A.; Park, Kyung-Sun; JIANG, JI-LONG; KIM, YONG-CHUL; Olah, Mark E.; Stiles, Gary L.; Ji, Xiao-duo

    1997-01-01

    The effects of putative A3 adenosine receptor antagonists of three diverse chemical classes (the flavonoid MRS 1067, the 6-phenyl-1,4-dihydropyridines MRS 1097 and MRS 1191, and the triazoloquinazo-line MRS 1220) were characterized in receptor binding and functional assays. MRS1067, MRS 1191 and MRS 1220 were found to be competitive in saturation binding studies using the agonist radioligand [125I]AB-MECA (N6-(4-amino-3-iodobenzyl)adenosine-5'-N-methyluronamide) at cloned human brain A3 recep...

  3. Wound Healing Is Accelerated by Agonists of Adenosine A2 (Gα s-linked) Receptors

    Montesinos, M. Carmen; Gadangi, Pratap; Longaker, Michael; Sung, Joanne; Levine, Jamie; Nilsen, Diana; Reibman, Joan; Min LI; Jiang, Chuan-Kui; Hirschhorn, Rochelle; Recht, Phoebe A.; Ostad, Edward; Levin, Richard I.; Cronstein, Bruce N.

    1997-01-01

    The complete healing of wounds is the final step in a highly regulated response to injury. Although many of the molecular mediators and cellular events of healing are known, their manipulation for the enhancement and acceleration of wound closure has not proven practical as yet. We and others have established that adenosine is a potent regulator of the inflammatory response, which is a component of wound healing. We now report that ligation of the Gαs-linked adenosine receptors on the cells o...

  4. Adenosine A1 Receptor Mediates Delayed Cardioprotective Effect of Sildenafil in Mouse

    Salloum, Fadi N.; Das, Anindita; Thomas, Christopher S; Yin, Chang; Kukreja, Rakesh C.

    2007-01-01

    Sildenafil induces powerful cardioprotection against ischemia/reperfusion (I/R) injury. Since adenosine is known to be major trigger of ischemic preconditioning, we hypothesized that A1 adenosine receptor (A1AR) activation plays a role in sildenafil-induced cardioprotective signaling. Adult male C57BL-wild type (WT) mice or their corresponding A1AR knockout (A1AR-KO) mice were treated intraperitoneally (i.p.) with either sildenafil (0.71 mg/kg, equivalent to 50 mg dose for a 70 kg patient) or...

  5. Adenosine and the adenosine A2A receptor agonist, CGS21680, upregulate CD39 and CD73 expression through E2F-1 and CREB in regulatory T cells isolated from septic mice.

    Bao, Rui; Shui, Xianqi; Hou, Jiong; Li, Jinbao; Deng, Xiaoming; Zhu, Xiaoyan; Yang, Tao

    2016-09-01

    The number of regulatory T cells (Treg cells) and the expression of ectonucleoside triphosphate diphosphohydrolase 1 (ENTPD1; also known as CD39) and 5'-ectonucleotidase (NT5E; also known as CD73) on the Treg cell surface are increased during sepsis. In this study, to determine the factors leading to the high expression of CD39 and CD73, and the regulation of the CD39/CD73/adenosine pathway in Treg cells under septic conditions, we constructed a mouse model of sepsis and separated the Treg cells using a flow cytometer. The Treg cells isolated from the peritoneal lavage and splenocytes of the mice were treated with adenosine or the specific adenosine A2A receptor agonist, CGS21680, and were transfected with specific siRNA targeting E2F transcription factor 1 (E2F-1) or cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), which are predicted transcription regulatory factors of CD39 or CD73. The regulatory relationships among these factors were then determined by western blot analysis and dual-luciferase reporter assay. In addition, changes in adenosine metabolism were measured in the treated cells. The results revealed that adenosine and CGS21680 significantly upregulated CD39 and CD73 expression (PTreg cell surface during sepsis. Adenosine and its A2A receptor agonist served as the signal transducer factors of the CD39/CD73/adenosine pathway, accelerating adenosine generation. Our study may benefit further research on adenosine metabolism for the treatment of sepsis. PMID:27430240

  6. Adenosine modulates hypoxia-induced responses in rat PC12 cells via the A2A receptor.

    Kobayashi, S; Conforti, L; Pun, R Y; Millhorn, D E

    1998-04-01

    1. The present study was undertaken to determine the role of adenosine in mediating the cellular responses to hypoxia in rat phaeochromocytoma (PC12) cells, an oxygen-sensitive clonal cell line. 2. Reverse transcriptase polymerase chain reaction studies revealed that PC12 cells express adenosine deaminase (the first catalysing enzyme of adenosine degradation) and the A2A and A2B adenosine receptors, but not the A1 or A3 adenosine receptors. 3. Whole-cell current- and voltage-clamp experiments showed that adenosine attenuated the hypoxia-induced membrane depolarization. The hypoxia-induced suppression of the voltage-sensitive potassium current (IK(V)) was markedly reduced by adenosine. Furthermore, extracellularly applied adenosine increased the peak amplitudes of IK(V) in a concentration-dependent manner. This increase was blocked by pretreatment not only with a non-specific adenosine receptor antagonist, 8-phenyltheophylline (8-PT), but also with a selective A2A receptor antagonist, ZM241385. 4. Ca2+ imaging studies using fura-2 acetoxymethyl ester (fura-2 AM) revealed that the increase in intracellular free Ca2+ during hypoxic exposure was attenuated significantly by adenosine. Voltage-clamp studies showed that adenosine inhibited the voltage-dependent Ca2+ currents (ICa) in a concentration-dependent fashion. This inhibition was also abolished by both 8-PT and ZM241385. 5. The modulation of both IK(V) and ICa by adenosine was prevented by intracellular application of an inhibitor of protein kinase A (PKA), PKA inhibitor fragment (6-22) amide. In addition, the effect of adenosine on either IK(V) or ICa was absent in PKA-deficient PC12 cells. 6. These results indicate that the modulatory effects of adenosine on the hypoxia-induced membrane responses of PC12 cells are likely to be mediated via activation of the A2A receptor, and that the PKA pathway is required for these modulatory actions. We propose that this modulation serves to regulate membrane excitability in

  7. Systemic administration of the adenosine A2A agonist CGS 21680 induces sedation at doses that suppress lever pressing and food intake

    Mingote, Susana; Pereira, Mariana; Farrar, Andrew M.; McLaughlin, Peter J.; Salamone, John D.

    2008-01-01

    Adenosine A2A receptors are involved in the regulation of several behavioral functions. Adenosine A2A antagonists exert antiparkinsonian effects in animal models, and adenosine A2A agonists suppress locomotion and impair various aspects of motor control. The present experiments were conducted to study the effects of low doses of the adenosine A2A agonist CGS 21680 on lever pressing, specific parameters of food intake, and sedation. In the first experiment, the effects of CGS 21680 on fixed ra...

  8. Dielectric spectra broadening as a signature for dipole-matrix interaction. III. Water in adenosine monophosphate/adenosine-5'-triphosphate solutions.

    Puzenko, Alexander; Levy, Evgeniya; Shendrik, Andrey; Talary, Mark S; Caduff, Andreas; Feldman, Yuri

    2012-11-21

    In this, the third part of our series on the dielectric spectrum symmetrical broadening of water, we consider the nucleotide aqueous solutions. Where in Parts I [E. Levy et al., J. Chem. Phys. 136, 114502 (2012)] and II [E. Levy et al., J. Chem. Phys. 136, 114503 (2012)], the dipole-dipole or ion-dipole interaction had a dominant feature, now the interplay between these two types of dipole-matrix interactions will be considered. We present the results of high frequency dielectric measurements of different concentrations of adenosine monophosphate/adenosine-5'-triphosphate aqueous solutions. We observed the Cole-Cole broadening of the main relaxation peak of the solvent in the solutions. Moreover, depending on the nucleotide concentration, we observed both types of dipole-matrix interaction. The 3D trajectory approach (described in detail in Part I) is applied in order to highlight the differences between the two types of interaction. PMID:23181321

  9. Adenosine induces vasoconstriction through Gi-dependent activation of phospholipase C in isolated perfused afferent arterioles of mice

    Hansen, Pernille B; Castrop, Hayo; Briggs, Josie; Schnermann, Jurgen

    2003-01-01

    Adenosine induces vasoconstriction of renal afferent arterioles through activation of A1 adenosine receptors (A1AR). A1AR are directly coupled to Gi/Go, resulting in inhibition of adenylate cyclase, but the contribution of this signaling pathway to smooth muscle cell activation is unclear. In......-induced vasoconstriction was stable for up to 30 min and was most pronounced in the most distal part of the afferent arterioles. Adenosine did not cause vasoconstriction in arterioles from A1AR-/- mice. Pretreatment with pertussis toxin (PTX) (400 ng/ml) for 2 h blocked the vasoconstricting action of adenosine or N(6......) blocked the constriction responses to both adenosine and angiotensin II. In contrast, the adenylate cyclase inhibitor SQ22536 (10 micro M) and the protein kinase A antagonist KT5720 (0.1 and 1 micro M) did not induce significant vasoconstriction of afferent arterioles. It is concluded that the...

  10. Adenosine A(1) Receptors in the Central Nervous System : Their Functions in Health and Disease, and Possible Elucidation by PET Imaging

    Paul, S.; Elsinga, P. H.; Ishiwata, K.; Dierckx, R. A. J. O.; van Waarde, A.

    2011-01-01

    Adenosine is a neuromodulator with several functions in the central nervous system (CNS), such as inhibition of neuronal activity in many signaling pathways. Most of the sedating, anxiolytic, seizure-inhibiting and protective actions of adenosine are mediated by adenosine A(1) receptors (A(1)R) on t

  11. Recent developments in A2B adenosine receptor ligands.

    Kalla, Rao V; Zablocki, Jeff; Tabrizi, Mojgan Aghazadeh; Baraldi, Pier Giovanni

    2009-01-01

    A selective, high-affinity A(2B) adenosine receptor (AR) antagonist will be useful as a pharmacological tool to help determine the role of the A(2B)AR in inflammatory diseases and angiogenic diseases. Based on early A(2B)AR-selective ligands with nonoptimal pharmaceutical properties, such as 15 (MRS 1754: K(i)(hA(2B)) = 2 nM; K(i)(hA(1)) = 403 nM; K(i)(hA(2A)) = 503 NM, and K(i)(hA(3)) = 570 nM), several groups have discovered second-generation A(2B)AR ligands that are suitable for development. Scientists at CV Therapeutics have discovered the selective, high-affinity A(2B)AR antagonist 22, a 8-(4-pyrazolyl)-xanthine derivative, (CVT-6883, K(i)(hA(2B)) = 22 nM; K(i)(hA(1)) = 1,940 nM; K(i)(hA(2A)) = 3,280; and K(i)(hA(3)) = 1,070 nM). Compound 22 has demonstrated favorable pharmacokinetic (PK) properties (T(1/2) = 4 h and F > 35% rat), and it is a functional antagonist at the A(2B)AR(K (B) = 6 nM). In a mouse model of asthma, compound 22 demonstrated a dose-dependent efficacy supporting the role of the A(2B)AR in asthma. In two Phase I clinical trails, 22 (CVT-6883) was found to be safe, well tolerated, and suitable for once-daily dosing. Baraldi et al. have independently discovered a selective, high-affinity A(2B)AR antagonist, 30 (MRE2029F20), 8-(5-pyrazolyl)-xanthine (K(i)(hA(2B)) = 5.5 nM; K(i)(hA(1)) = 200 nM; K(i)(hA(2A), A(3)) > 1,000, that has been selected for development in conjunction with King Pharmaceuticals. Compound 30 has been demonstrated to be a functional antagonist of the A(2B)AR, and it has been radiolabeled for use in pharmacological studies. A third compound, 58 (LAS-38096), is a 2-aminopyrimidine derivative (discovered by the Almirall group) that has high A(2B)AR affinity and selectivity (K(i)(hA(2B)) = 17 nM; K(i)(hA(1)) > 1,000 nM; K(i)(hA(2A)) > 2,500; and K(i)(hA(3)) > 1,000 nM), and 58 has been moved into preclinical safety testing. A fourth selective, high-affinity A(2B)AR antagonist, 54 (OSIP339391 K(i))(hA(2B)) = 0.5 nM; K(i))(hA(1

  12. High fetal plasma adenosine concentration: a role for the fetus in preeclampsia?

    Espinoza, Jimmy

    2012-02-01

    OBJECTIVE: Clinical observations suggest a role for the fetus in the maternal manifestations of preeclampsia, but the possible signaling mechanisms remain unclear. This study compares the fetal plasma concentrations of adenosine from normal pregnancies with those from preeclampsia. STUDY DESIGN: This secondary data analysis included normal pregnancies (n = 27) and patients with preeclampsia (n = 39). Patients with preeclampsia were subclassified into patients with (n = 25) and without (n = 14) abnormal uterine artery Doppler velocimetry (UADV). RESULTS: Fetal plasma concentrations of adenosine were significantly higher in patients with preeclampsia (1.35 +\\/- 0.09 mumol\\/L) than in normal pregnancies (0.52 +\\/- 0.06 mumol\\/L; P < .0001). Fetal plasma concentrations of adenosine in patients with preeclampsia with abnormal UADV (1.78 +\\/- 0.15 mumol\\/L), but not with normal UADV (0.58 +\\/- 0.14 mumol\\/L), were significantly higher than in normal pregnancies (P < .0001). CONCLUSION: Patients with preeclampsia with sonographic evidence of chronic uteroplacental ischemia have high fetal plasma concentrations of adenosine.

  13. Passive targeting of ischemic-reperfused myocardium with adenosine-loaded silica nanoparticles

    Galagudza M

    2012-04-01

    Full Text Available Michael Galagudza1, Dmitry Korolev1, Viktor Postnov2, Elena Naumisheva2, Yulia Grigorova3, Ivan Uskov1, Eugene Shlyakhto11Institute of Experimental Medicine, VA Almazov Federal Heart, Blood and Endocrinology Center, 2Chemical Faculty, St Petersburg State University, 3Department of Pathophysiology, IP Pavlov State Medical University, St Petersburg, Russian FederationAbstract: Pharmacological agents suggested for infarct size limitation have serious side effects when used at cardioprotective doses which hinders their translation into clinical practice. The solution to the problem might be direct delivery of cardioprotective drugs into ischemic-reperfused myocardium. In this study, we explored the potential of silica nanoparticles for passive delivery of adenosine, a prototype cardioprotective agent, into ischemic-reperfused heart tissue. In addition, the biodegradation of silica nanoparticles was studied both in vitro and in vivo. Immobilization of adenosine on the surface of silica nanoparticles resulted in enhancement of adenosine-mediated infarct size limitation in the rat model. Furthermore, the hypotensive effect of adenosine was attenuated after its adsorption on silica nanoparticles. We conclude that silica nanoparticles are biocompatible materials that might potentially be used as carriers for heart-targeted drug delivery.Keywords: silica nanoparticles, targeted drug delivery, myocardium, ischemia, reperfusion

  14. Outcome of hematopoietic stem cell transplantation for adenosine deaminase-deficient severe combined immunodeficiency

    Hassan, Amel; Booth, Claire; Brightwell, Alex; Allwood, Zoe; Veys, Paul; Rao, Kanchan; Hoenig, Manfred; Friedrich, Wilhelm; Gennery, Andrew; Slatter, Mary; Bredius, Robbert; Finocchi, Andrea; Cancrini, Caterina; Aiuti, Alessandro; Porta, Fulvio; Lanfranchi, Arnalda; Ridella, Michela; Steward, Colin; Filipovich, Alexandra; Marsh, Rebecca; Bordon, Victoria; Al-Muhsen, Saleh; Al-Mousa, Hamoud; Alsum, Zobaida; Al-Dhekri, Hasan; Al Ghonaium, Abdulaziz; Speckmann, Carsten; Fischer, Alain; Mahlaoui, Nizar; Nichols, Kim E.; Grunebaum, Eyal; Al Zahrani, Daifulah; Roifman, Chaim M.; Boelens, Jaap; Davies, E. Graham; Cavazzana-Calvo, Marina; Notarangelo, Luigi; Gaspar, H. Bobby

    2012-01-01

    Deficiency of the purine salvage enzyme adenosine deaminase leads to SCID (ADA-SCID). Hematopoietic cell transplantation (HCT) can lead to a permanent cure of SCID; however, little data are available on outcome of HCT for ADA-SCID in particular. In this multicenter retrospective study, we analyzed o

  15. Brain stem adenosine receptors modulate centrally mediated hypotensive responses in conscious rats: A review

    Noha N. Nassar

    2015-05-01

    Full Text Available Adenosine is implicated in the modulation of cardiovascular responses either at the peripheral or at central level in experimental animals. However, there are no dedicated reviews on the involvement of adenosine in mediating the hypotensive response of centrally administered clonidine in general and specifically in aortically barodenervated rats (ABD. The conscious ABD rat model exhibits surgically induced baroreflex dysfunction and exaggerated hypotensive response, compared with conscious sham-operated (SO rats. The current review focuses on, the role of adenosine receptors in blood pressure (BP regulation and their possible crosstalk with other receptors e.g. imidazoline (I1 and alpha (α2A adrenergic receptor (AR. The former receptor is a molecular target for clonidine, whose hypotensive effect is enhanced approx. 3-fold in conscious ABD rats. We also discussed how the balance between the brain stem adenosine A1 and A2A receptors is regulated by baroreceptors and how such balance influences the centrally mediated hypotensive responses. The use of the ABD rat model yielded insight into the downstream signaling cascades following clonidine-evoked hypotension in a surgical model of baroreflex dysfunction.

  16. Adenosine A2A Receptors Modulate Acute Injury and Neuroinflammation in Brain Ischemia

    Felicita Pedata

    2014-01-01

    Full Text Available The extracellular concentration of adenosine in the brain increases dramatically during ischemia. Adenosine A2A receptor is expressed in neurons and glial cells and in inflammatory cells (lymphocytes and granulocytes. Recently, adenosine A2A receptor emerged as a potential therapeutic attractive target in ischemia. Ischemia is a multifactorial pathology characterized by different events evolving in the time. After ischemia the early massive increase of extracellular glutamate is followed by activation of resident immune cells, that is, microglia, and production or activation of inflammation mediators. Proinflammatory cytokines, which upregulate cell adhesion molecules, exert an important role in promoting recruitment of leukocytes that in turn promote expansion of the inflammatory response in ischemic tissue. Protracted neuroinflammation is now recognized as the predominant mechanism of secondary brain injury progression. A2A receptors present on central cells and on blood cells account for important effects depending on the time-related evolution of the pathological condition. Evidence suggests that A2A receptor antagonists provide early protection via centrally mediated control of excessive excitotoxicity, while A2A receptor agonists provide protracted protection by controlling massive blood cell infiltration in the hours and days after ischemia. Focus on inflammatory responses provides for adenosine A2A receptor agonists a wide therapeutic time-window of hours and even days after stroke.

  17. Adenosine triphosphatase, acetylcholinesterase and sulfhydryl groups of rat skin at local x-ray irradiation

    The activity of acetylcholinesterase (ACE), adenosine triphosphatase (ATPase), and sulfhydryl groups(SH-groups) in different structural elements of skin in the course of radiation epidermitis was studied. The posterior extremities of Wistar rats were exposed to single x-ray irradiation at a dose of 30 Gy

  18. Efficacy of Adenosine for Acute Treatment of Supraventricular Tachycardia in Infants and Children

    Seyed Mohammad Dalili

    2008-10-01

    Full Text Available Background: This study was done to assess the efficacy and adverse effects of the different doses of adenosine in the pediatric age group with respect to multiple patient variables. Methods: Over a period of 1 year, 86 occasions of supraventricular tachycardia (SVT were treated with adenosine in 81 infants and children aged between 18 days and 12 years (median of 1.3 years, SD=3. Adenosine efficacy was evaluated in terms of the patients’ demographics, SVT rate, electrocardiogram characteristics, and route of drug administration.Results: The dose of 50μg/kg was effective only in 24% of the SVT cases, and the additional doses of 100μg/kg, 150μg/kg, and 200μg/kg were effective in another 29% of the cases. The drug efficacy was higher in the infants than that in the older children. There were no predictors other than age for the estimation of the efficacy of the drug. Conclusion: Our findings showed that the current recommended doses of adenosine are ineffective in the vast majority of children and infants with SVT. No patient-related factor other than age seems to affect the efficacy of the drug

  19. SIGNIFICANCE OF ADENOSINE DEAMINASE SERUM CONCENTRATIONS IN THE DIAGNOSIS OF EXTRA-PULMONARY TUBERCULOSIS

    Stevanovic G,

    2011-06-01

    Full Text Available Extra pulmonary tuberculosis (EPTB is a growing problem worldwide. Due to the nature of the disease, the diversity of clinical pictures as well as its minor epidemiological importance, the diagnosis is difficult and often late.In addition to standard TB diagnostic techniques use of new biochemical (surrogate markers are increased. With this work we wanted to examine the usefulness of serum adenosine deaminase levels as a diagnostic parameter for EPTB.The work included 116 patients with fever of unknown origin in which tuberculosis or infectious mononucleosis was not proven and 51 person who had proven EPTB. Correlated adenosine deaminase levels between these two groups we obtained significantly higher values ​​in patients with EPTB. The calculated sensitivity was 0.56, specificity 0.89, positive predictive value 0.80 and negative predictive value 0.72. Certain reducing of the values observed during anti TB therapy. In previous studies the diagnostic importance of adenosine deaminase in the diagnosis of tuberculosis serosityes was demonstrated. The significance of serum levels in diagnosis is rarely evaluated during EPTB. Our findings are similar to the results of authors who have conducted such testing in the pediatric population.Increased concentrations of serum adenosine deaminase have shown the potential of usable screening test and can be used as an indicative EPTB parameter. To fully assess its diagnostic significance require future clinical research.

  20. Hematopoiesis in 5-Fluorouracil-Treated Adenosine A(3) Receptor Knock-Out Mice

    Hofer, Michal; Pospíšil, Milan; Dušek, L.; Hoferová, Zuzana; Komůrková, Denisa

    2015-01-01

    Roč. 64, č. 2 (2015), s. 255-262. ISSN 0862-8408 Institutional support: RVO:68081707 Keywords : Adenosine A(3) receptor knock-out mice * Hematopoiesis * 5-fluorouracil-induced hematotoxicity Subject RIV: BO - Biophysics Impact factor: 1.293, year: 2014

  1. A2BR adenosine receptor modulates sweet taste in circumvallate taste buds.

    Shinji Kataoka

    Full Text Available In response to taste stimulation, taste buds release ATP, which activates ionotropic ATP receptors (P2X2/P2X3 on taste nerves as well as metabotropic (P2Y purinergic receptors on taste bud cells. The action of the extracellular ATP is terminated by ectonucleotidases, ultimately generating adenosine, which itself can activate one or more G-protein coupled adenosine receptors: A1, A2A, A2B, and A3. Here we investigated the expression of adenosine receptors in mouse taste buds at both the nucleotide and protein expression levels. Of the adenosine receptors, only A2B receptor (A2BR is expressed specifically in taste epithelia. Further, A2BR is expressed abundantly only in a subset of taste bud cells of posterior (circumvallate, foliate, but not anterior (fungiform, palate taste fields in mice. Analysis of double-labeled tissue indicates that A2BR occurs on Type II taste bud cells that also express Gα14, which is present only in sweet-sensitive taste cells of the foliate and circumvallate papillae. Glossopharyngeal nerve recordings from A2BR knockout mice show significantly reduced responses to both sucrose and synthetic sweeteners, but normal responses to tastants representing other qualities. Thus, our study identified a novel regulator of sweet taste, the A2BR, which functions to potentiate sweet responses in posterior lingual taste fields.

  2. Hyperalgesia, anxiety, and decreased hypoxic neuroprotection in mice lacking the adenosine A1 receptor.

    Johansson, B; Halldner, L; Dunwiddie, T V; Masino, S A; Poelchen, W; Giménez-Llort, L; Escorihuela, R M; Fernández-Teruel, A; Wiesenfeld-Hallin, Z; Xu, X J; Hårdemark, A; Betsholtz, C; Herlenius, E; Fredholm, B B

    2001-07-31

    Caffeine is believed to act by blocking adenosine A(1) and A(2A) receptors (A(1)R, A(2A)R), indicating that some A(1) receptors are tonically activated. We generated mice with a targeted disruption of the second coding exon of the A(1)R (A(1)R(-/-)). These animals bred and gained weight normally and had a normal heart rate, blood pressure, and body temperature. In most behavioral tests they were similar to A(1)R(+/+) mice, but A(1)R(-/-) mice showed signs of increased anxiety. Electrophysiological recordings from hippocampal slices revealed that both adenosine-mediated inhibition and theophylline-mediated augmentation of excitatory glutamatergic neurotransmission were abolished in A(1)R(-/-) mice. In A(1)R(+/-) mice the potency of adenosine was halved, as was the number of A(1)R. In A(1)R(-/-) mice, the analgesic effect of intrathecal adenosine was lost, and thermal hyperalgesia was observed, but the analgesic effect of morphine was intact. The decrease in neuronal activity upon hypoxia was reduced both in hippocampal slices and in brainstem, and functional recovery after hypoxia was attenuated. Thus A(1)Rs do not play an essential role during development, and although they significantly influence synaptic activity, they play a nonessential role in normal physiology. However, under pathophysiological conditions, including noxious stimulation and oxygen deficiency, they are important. PMID:11470917

  3. Erythropoiesis- and Thrombopoiesis-Characterizing Parameters in Adenosine A(3) Receptor Knock-Out Mice

    Hofer, Michal; Pospíšil, Milan; Dušek, L.; Hoferová, Zuzana; Weiterová, Lenka

    2013-01-01

    Roč. 62, č. 3 (2013), s. 305-311. ISSN 0862-8408 R&D Projects: GA ČR(CZ) GAP303/11/0128 Institutional support: RVO:68081707 Keywords : ELEVATING EXTRACELLULAR ADENOSINE * COLONY-STIMULATING FACTOR * HEMATOPOIETIC PROGENITOR CELLS Subject RIV: BO - Biophysics Impact factor: 1.487, year: 2013

  4. Structural basis of the substrate specificity of Bacillus cereus adenosine phosphorylase

    Dessanti, Paola; Zhang, Yang; Allegrini, Simone; Tozzi, Maria Grazia; Sgarrella, Francesco; Ealick, Steven E. (Cornell); (Sassari); (Pisa)

    2012-10-08

    Purine nucleoside phosphorylases catalyze the phosphorolytic cleavage of the glycosidic bond of purine (2{prime}-deoxy)nucleosides, generating the corresponding free base and (2{prime}-deoxy)ribose 1-phosphate. Two classes of PNPs have been identified: homotrimers specific for 6-oxopurines and homohexamers that accept both 6-oxopurines and 6-aminopurines. Bacillus cereus adenosine phosphorylase (AdoP) is a hexameric PNP; however, it is highly specific for 6-aminopurines. To investigate the structural basis for the unique substrate specificity of AdoP, the active-site mutant D204N was prepared and kinetically characterized and the structures of the wild-type protein and the D204N mutant complexed with adenosine and sulfate or with inosine and sulfate were determined at high resolution (1.2-1.4 {angstrom}). AdoP interacts directly with the preferred substrate through a hydrogen-bond donation from the catalytically important residue Asp204 to N7 of the purine base. Comparison with Escherichia coli PNP revealed a more optimal orientation of Asp204 towards N7 of adenosine and a more closed active site. When inosine is bound, two water molecules are interposed between Asp204 and the N7 and O6 atoms of the nucleoside, thus allowing the enzyme to find alternative but less efficient ways to stabilize the transition state. The mutation of Asp204 to asparagine led to a significant decrease in catalytic efficiency for adenosine without affecting the efficiency of inosine cleavage.

  5. Downregulation of adenosine and P2X receptor-mediated cardiovascular responses in heart failure rats

    Zhao, Xin; Sun, X Y; Erlinge, D;

    2000-01-01

    degradation product adenosine, experiments were performed in a rat model of ischaemic CHF. In this model, ischaemia was induced in rats by ligation of the left coronary artery. Our results demonstrate that there is a selective downregulation of P2X receptor-mediated pressor effects, while the hypotensive...

  6. Stimulation of Glia Reveals Modulation of Mammalian Spinal Motor Networks by Adenosine.

    David Acton

    Full Text Available Despite considerable evidence that glia can release modulators to influence the excitability of neighbouring neurons, the importance of gliotransmission for the operation of neural networks and in shaping behaviour remains controversial. Here we characterise the contribution of glia to the modulation of the mammalian spinal central pattern generator for locomotion, the output of which is directly relatable to a defined behaviour. Glia were stimulated by specific activation of protease-activated receptor-1 (PAR1, an endogenous G-protein coupled receptor preferentially expressed by spinal glia during ongoing activity of the spinal central pattern generator for locomotion. Selective activation of PAR1 by the agonist TFLLR resulted in a reversible reduction in the frequency of locomotor-related bursting recorded from ventral roots of spinal cord preparations isolated from neonatal mice. In the presence of the gliotoxins methionine sulfoximine or fluoroacetate, TFLLR had no effect, confirming the specificity of PAR1 activation to glia. The modulation of burst frequency upon PAR1 activation was blocked by the non-selective adenosine-receptor antagonist theophylline and by the A1-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine, but not by the A2A-receptor antagonist SCH5826, indicating production of extracellular adenosine upon glial stimulation, followed by A1-receptor mediated inhibition of neuronal activity. Modulation of network output following glial stimulation was also blocked by the ectonucleotidase inhibitor ARL67156, indicating glial release of ATP and its subsequent degradation to adenosine rather than direct release of adenosine. Glial stimulation had no effect on rhythmic activity recorded following blockade of inhibitory transmission, suggesting that glial cell-derived adenosine acts via inhibitory circuit components to modulate locomotor-related output. Finally, the modulation of network output by endogenous adenosine was found to

  7. Adenosine stress myocardial perfusion scintigraphy in pediatric patients after arterial switch operation

    Arterial switch operation (ASO) has become the established treatment for correction of transposition of great arteries (TGA). Despite the immediate correction of abnormal hemodynamics, acute and delayed complications related to the coronaries may cause morbidity and mortality. We evaluated the incidence of perfusion abnormalities and safety of adenosine by stress–rest myocardial perfusion single-photon emission computed tomography (SPECT) [myocardial perfusion scintigraphy (MPS)] using Tc-99m Sestamibi (MIBI) in asymptomatic children post-ASO. Prospective study. We conducted a prospective, single-institutional study where stress–rest MPS was performed on 10 children of age between 1.25 and 6 years. Two of the patients had additional ventricular septal defect, one patient had left ventricular outflow tract obstruction, and another had Taussig–Bing anomaly. All the patients underwent corrective surgery as a single-stage procedure at the age of 176 ± 212 days (range 9-560 days). Adenosine was administered at a rate of 140 μg/kg/min intravenously as continuous infusion for duration of 6 min. All the continuous variables were summarized as mean ± standard deviation, or range and median. Mann–Whitney test for unpaired data and Wilcoxon Rank test for paired samples were used. The average increase in heart rate over the basal heart rate after adenosine stress was 59.7 ± 17.0%. No acute or remote complications were observed in any case. None of the patients demonstrated myocardial perfusion defects, either at rest or after adenosine stress. MPS post-adenosine induced vasodilatation is safe and feasible in patients of ASO for transposition of great arteries. One-stage repair, implantation of excised coronary buttons within neo-aortic sinus, and minimal or no mobilization of proximal coronaries may eliminate the occurrence of perfusion defects in patients of corrected TGA

  8. Role of nitric oxide in adenosine-induced vasodilation in humans

    Costa, F.; Biaggioni, I.; Robertson, D. (Principal Investigator)

    1998-01-01

    Vasodilation is one of the most prominent effects of adenosine and one of the first to be recognized, but its mechanism of action is not completely understood. In particular, there is conflicting information about the potential contribution of endothelial factors. The purpose of this study was to explore the role of nitric oxide in the vasodilatory effect of adenosine. Forearm blood flow responses to intrabrachial adenosine infusion (125 microg/min) were assessed with venous occlusion plethysmography during intrabrachial infusion of saline or the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) (12.5 mg/min). Intrabrachial infusions of acetylcholine (50 microg/min) and nitroprusside (3 microg/min) were used as a positive and negative control, respectively. These doses were chosen to produce comparable levels of vasodilation. In a separate study, a second saline infusion was administered instead of L-NMMA to rule out time-related effects. As expected, pretreatment with L-NMMA reduced acetylcholine-induced vasodilation; 50 microg/min acetylcholine increased forearm blood flow by 150+/-43% and 51+/-12% during saline and L-NMMA infusion, respectively (P<.01, n=6). In contrast, L-NMMA did not affect the increase in forearm blood flow produced by 3 microg/min nitroprusside (165+/-30% and 248+/-41% during saline and L-NMMA, respectively) or adenosine (173+/-48% and 270+/-75% during saline and L-NMMA, respectively). On the basis of our observations, we conclude that adenosine-induced vasodilation is not mediated by nitric oxide in the human forearm.

  9. Mechanisms of the adenosine A2A receptor-induced sensitization of esophageal C fibers.

    Brozmanova, M; Mazurova, L; Ru, F; Tatar, M; Hu, Y; Yu, S; Kollarik, M

    2016-02-01

    Clinical studies indicate that adenosine contributes to esophageal mechanical hypersensitivity in some patients with pain originating in the esophagus. We have previously reported that the esophageal vagal nodose C fibers express the adenosine A2A receptor. Here we addressed the hypothesis that stimulation of the adenosine A2A receptor induces mechanical sensitization of esophageal C fibers by a mechanism involving transient receptor potential A1 (TRPA1). Extracellular single fiber recordings of activity originating in C-fiber terminals were made in the ex vivo vagally innervated guinea pig esophagus. The adenosine A2A receptor-selective agonist CGS21680 induced robust, reversible sensitization of the response to esophageal distention (10-60 mmHg) in a concentration-dependent fashion (1-100 nM). At the half-maximally effective concentration (EC50: ≈3 nM), CGS21680 induced an approximately twofold increase in the mechanical response without causing an overt activation. This sensitization was abolished by the selective A2A antagonist SCH58261. The adenylyl cyclase activator forskolin mimicked while the nonselective protein kinase inhibitor H89 inhibited mechanical sensitization by CGS21680. CGS21680 did not enhance the response to the purinergic P2X receptor agonist α,β-methylene-ATP, indicating that CGS21680 does not nonspecifically sensitize to all stimuli. Mechanical sensitization by CGS21680 was abolished by pretreatment with two structurally different TRPA1 antagonists AP18 and HC030031. Single cell RT-PCR and whole cell patch-clamp studies in isolated esophagus-specific nodose neurons revealed the expression of TRPA1 in A2A-positive C-fiber neurons and demonstrated that CGS21682 potentiated TRPA1 currents evoked by allylisothiocyanate. We conclude that stimulation of the adenosine A2A receptor induces mechanical sensitization of nodose C fibers by a mechanism sensitive to TRPA1 antagonists indicating the involvement of TRPA1. PMID:26564719

  10. Nucleus tractus solitarii A(2a) adenosine receptors inhibit cardiopulmonary chemoreflex control of sympathetic outputs.

    Minic, Zeljka; O'Leary, Donal S; Scislo, Tadeusz J

    2014-02-01

    Previously we have shown that stimulation of inhibitory A1 adenosine receptors located in the nucleus tractus solitarii (NTS) attenuates cardiopulmonary chemoreflex (CCR) evoked inhibition of renal, adrenal and lumbar sympathetic nerve activity and reflex decreases in arterial pressure and heart rate. Activation of facilitatory A2a adenosine receptors, which dominate over A1 receptors in the NTS, contrastingly alters baseline activity of regional sympathetic outputs: it decreases renal, increases adrenal and does not change lumbar nerve activity. Considering that NTS A2a receptors may facilitate release of inhibitory transmitters we hypothesized that A2a receptors will act in concert with A1 receptors differentially inhibiting regional sympathetic CCR responses (adrenal>lumbar>renal). In urethane/chloralose anesthetized rats (n=38) we compared regional sympathetic responses evoked by stimulation of the CCR with right atrial injections of serotonin 5HT3 receptor agonist, phenylbiguanide, (1-8μg/kg) before and after selective stimulation, blockade or combined blockade and stimulation of NTS A2a adenosine receptors (microinjections into the NTS of CGS-21680 0.2-20pmol/50nl, ZM-241385 40pmol/100nl or ZM-241385+CGS-21680, respectively). We found that stimulation of A2a adenosine receptors uniformly inhibited the regional sympathetic and hemodynamic reflex responses and this effect was abolished by the selective blockade of NTS A2a receptors. This indicates that A2a receptor triggered inhibition of CCR responses and the contrasting shifts in baseline sympathetic activity are mediated via different mechanisms. These data implicate that stimulation of NTS A2a receptors triggers unknown inhibitory mechanism(s) which in turn inhibit transmission in the CCR pathway when adenosine is released into the NTS during severe hypotension. PMID:24216055

  11. Value of adenosine infusion for infarct size determination using real-time myocardial contrast echocardiography

    da Luz Protásio

    2006-02-01

    Full Text Available Abstract Background Myocardial contrast echocardiography has been used for determination of infarct size (IS in experimental models. However, with intermittent harmonic imaging, IS seems to be underestimated immediately after reperfusion due to areas with preserved, yet dysfunctional, microvasculature. The use of exogenous vasodilators showed to be useful to unmask these infarcted areas with depressed coronary flow reserve. This study was undertaken to assess the value of adenosine for IS determination in an open-chest canine model of coronary occlusion and reperfusion, using real-time myocardial contrast echocardiography (RTMCE. Methods Nine dogs underwent 180 minutes of coronary occlusion followed by reperfusion. PESDA (Perfluorocarbon-Exposed Sonicated Dextrose Albumin was used as contrast agent. IS was determined by RTMCE before and during adenosine infusion at a rate of 140 mcg·Kg-1·min-1. Post-mortem necrotic area was determined by triphenyl-tetrazolium chloride (TTC staining. Results IS determined by RTMCE was 1.98 ± 1.30 cm2 and increased to 2.58 ± 1.53 cm2 during adenosine infusion (p = 0.004, with good correlation between measurements (r = 0.91; p 2 and showed no significant difference with IS determined by RTMCE before or during hyperemia. A slight better correlation between RTMCE and TTC measurements was observed during adenosine (r = 0.99; p Conclusion RTMCE can accurately determine IS in immediate period after acute myocardial infarction. Adenosine infusion results in a slight better detection of actual size of myocardial damage.

  12. Electrochemical aptasensor for the detection of adenosine by using PdCu@MWCNTs-supported bienzymes as labels.

    Wu, Dan; Ren, Xiang; Hu, Lihua; Fan, Dawei; Zheng, Yang; Wei, Qin

    2015-12-15

    A highly sensitive electrochemical adenosine aptasensor was fabricated by covalently immobilizing 3'-NH2-terminated capture probe (SSDNA1) and thionine (TH) on Au-GS modified glassy carbon electrode. 3'-SH-terminated adenosine aptamer (SSDNA2) was adsorbed onto palladium/copper alloyed supported on MWCNTs (PdCu@MWCNTs)-conjugated multiple bienzymes, glucose oxidase (GOx), and horseradish peroxidase (HRP) (SSDNA2/PdCu@MWCNTs/HRP/GOx). Then, it was immobilized onto the electrode surface through the hybridization between the adenosine aptamer and the capture probe. The signal was amplified based on the gradual electrocatalytic reduction of GOx-generated hydrogen peroxide by the multiple HRP through the mediating ability of the loaded multiple TH. However, the peak current of TH decreased in the presence of adenosine because the interaction between adenosine and its aptamer made SSDNA2/PdCu@MWCNTs/HRP/GOx release from the modified electrode. Various experimental parameters have been optimized for the detection of adenosine and tests for selectivity, reproducibility and stability have also been performed. Under the optimal condition, the proposed aptasensor displayed a wide linear range (10-400 nM) with the low detection limit (2.5 nM), which has been applied in human serum samples with satisfactory results. Thus, the combination of Au-GS as a sensor platform and PdCu@MWCNTs/HRP/GOx as labels can be a promising amplification strategy for highly sensitive adenosine detection. PMID:26164010

  13. Activation of adenosine receptors and inhibition of cyclooxygenases: two recent pharmacological approaches to modulation of radiation suppressed hematopoiesis

    Searching for drugs conforming to requirements for protection and/or treatment of radiation-induced damage belongs to the most important tasks of current radiobiology. In the Laboratory of Experimental Hematology, Institute of Biophysics, v.v.i., Academy of Sciences of the Czech Republic, Brno, Czech Republic, two original approaches for stimulation of radiation-suppressed hematopoiesis have been tested in recent years, namely activation of adenosine receptors and inhibition of cyclooxygenases. Non-selective activation of adenosine receptors, induced by combined administration of dipyridamole, a drug preventing adenosine uptake and supporting thus its extracellular receptor-mediated action, and adenosine monophosphate, an adenosine prodrug, has been found to stimulate hematopoiesis when the drugs were given either pre- or post-irradiation. When synthetic adenosine receptor agonists selective for individual adenosine receptor subtypes were tested, stimulatory effects in myelosuppressed mice have been found after administration of IB-MECA, a selective adenosine A3 receptor agonist. Non-selective cyclooxygenase inhibitors, inhibiting both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), indomethacin, diclofenac, or flurbiprofen, have been observed to act positively on radiation-perturbed hematopoiesis in sublethally irradiated mice. However, their undesirable gastrointestinal side effects have been found to negatively influence survival of lethally irradiated animals. Recently tested selective COX-2 inhibitor meloxicam, preserving protective action of COX-1-synthesized prostaglandins in the gastrointestinal tissues, has been observed to retain the hematopoiesis-stimulating effects of non-selective cyclooxygenase inhibitors and to improve the survival of animals exposed to lethal radiation doses. These findings bear evidence for the possibility to use selective adenosine A3 receptor agonists and selective COX-2 inhibitors in human practice for treatment of

  14. Interfacial molecular recognition of adenine, adenosine and ATP by a C60-uracil adduct via complementary base pairing

    Marczak, Renata; Hoang, Vu T.; Noworyta, Krzysztof; Zandler, Melvin E.; Kutner, Wlodzimierz; D'Souza, Francis

    2002-10-01

    A new C60-uracil adduct was demonstrated to recognize adenine, adenosine, or adenosine 5'-triphosphate (ATP) via complementary base pairing which led to complex formation. The base-pairing mechanism was modeled by ab initio B3LYP/3-21G(*) calculations which revealed the Watson-Crick (A-T) interactions. Stable "expanded liquid" Langmuir films of the complexes were prepared with the limiting area per molecule increasing for different subphase composition in the order: water < adenine < adenosine < ATP solution. Comparison of experimental and calculated areas per molecule and dipole moments suggest both prevailing horizontal orientation of the complexes in films.

  15. 腺苷和睡眠觉醒调节%Adenosine and Sleep-Wake Regulation

    曲卫敏; 孙宇; 许奇; 黄志力

    2011-01-01

    腺苷作为神经调质,调节多种神经生物学功能.随觉醒时间延长,动物脑内腺苷水平逐渐增高,在睡眠期显著降低.因此,腺苷被认为是调节睡眠的内稳态因子之一.腺苷受体(receptor,R)有A1R、A2AR、A2BR和A3R四种亚型,其中A1R和A2AR与诱导睡眠相关.激活A1R可抑制促觉醒神经元诱导睡眠,也可抑制促眠神经元导致觉醒,其作用存在脑区依赖性.A2AR介导内源性前列素D:的促眠作用,A2AR激动剂具有最强的促眠效应,阻断A2AR引起觉醒,在睡眠觉醒调节中扮演重要角色.本文综述腺苷调节睡眠和觉醒的研究进展,讨论腺苷受体激动剂和拮抗剂在睡眠疾病治疗中的潜在价值及存在问题.%Adenosine may function as a neuromodulator in the central nervous system. The extracellular concentration of adenosine increases in the brain during prolonged wakefulness and decreases during the sleep recovery penod. Therefore, adenosine is proposed to act as one of homeostatic regulators of sleep.There are four adenosine receptor subtypes, adenosine A1 receptor (A1R), A2AR, A2BR and A3R. Both the adenosine A1R and A2AR are demonstrated to be involved in sleep induction. Inhibition of wake-promoting neurons via the A1R mediates the sleep-inducing effects of adenosine, whereas activation of A1R in sleep-promoting neurons induces wakefulness, suggesting that A1R regulates the sleep-wake cycle in a site-dependent manner. On the other hand, the A2AR mediates the somnogenic effects of endogenous PGD2.A2AR agonist induces the most potent sleep similar to physiological sleep among somnogens reported so far,whereas blockade of A2AR induces wakefulness. Among adenosine receptors responsible for sleep induction,the role of A2AR is predominant. This paper presents an overview of the current knowledge about the role of adenosine in the sleep-wake regulation and briefly discusses the potential therapeutic applications of agonists and antagonists of these

  16. Regulation of aggregate size and pattern by adenosine and caffeine in cellular slime molds

    Jaiswal Pundrik

    2012-01-01

    Full Text Available Abstract Background Multicellularity in cellular slime molds is achieved by aggregation of several hundreds to thousands of cells. In the model slime mold Dictyostelium discoideum, adenosine is known to increase the aggregate size and its antagonist caffeine reduces the aggregate size. However, it is not clear if the actions of adenosine and caffeine are evolutionarily conserved among other slime molds known to use structurally unrelated chemoattractants. We have examined how the known factors affecting aggregate size are modulated by adenosine and caffeine. Result Adenosine and caffeine induced the formation of large and small aggregates respectively, in evolutionarily distinct slime molds known to use diverse chemoattractants for their aggregation. Due to its genetic tractability, we chose D. discoideum to further investigate the factors affecting aggregate size. The changes in aggregate size are caused by the effect of the compounds on several parameters such as cell number and size, cell-cell adhesion, cAMP signal relay and cell counting mechanisms. While some of the effects of these two compounds are opposite to each other, interestingly, both compounds increase the intracellular glucose level and strengthen cell-cell adhesion. These compounds also inhibit the synthesis of cAMP phosphodiesterase (PdsA, weakening the relay of extracellular cAMP signal. Adenosine as well as caffeine rescue mutants impaired in stream formation (pde4- and pdiA- and colony size (smlA- and ctnA- and restore their parental aggregate size. Conclusion Adenosine increased the cell division timings thereby making large number of cells available for aggregation and also it marginally increased the cell size contributing to large aggregate size. Reduced cell division rates and decreased cell size in the presence of caffeine makes the aggregates smaller than controls. Both the compounds altered the speed of the chemotactic amoebae causing a variation in aggregate size

  17. Characterization of the binding of a novel nonxanthine adenosine antagonist radioligand, ( sup 3 H)CGS 15943, to multiple affinity states of the adenosine A1 receptor in the rat cortex

    Jarvis, M.F.; Williams, M.; Do, U.H.; Sills, M.A. (CIBA-GEIGY Corp., Summit, NJ (USA))

    1991-01-01

    The triazoloquinazoline CGS 15943 is the first reported nonxanthine adenosine antagonist that has high affinity for brain adenosine receptors. In the present study, the binding of (3H) CGS 15943 to recognition sites in rat cortical membranes was characterized. Saturation experiments revealed that (3H)CGS 15943 labeled a single class of recognition sites with high affinity and limited capacity. Competition studies revealed that the binding of (3H)CGS 15943 was consistent with the labeling of brain adenosine A1 receptors. Adenosine agonists inhibited 1 nM (3H)CGS 15943 binding with the following order of activity N6-cyclopentyladenosine (IC50 = 15 nM) greater than 2-chloroadenosine greater than (R)-N6-phenylisopropyladenosine greater than 5'-N6-ethylcarboxamidoadenosine greater than (S)N6-phenylisopropyladenosine greater than CGS 21680 greater than CV 1808 (IC50 greater than 10,000 nM). The potency order for adenosine antagonists was CGS 15943 (IC50 = 5 nM) greater than 8-phenyltheophylline greater than 1,3-dipropyl-8-(4-amino-2-chloro)phenylxanthine greater than 1,3-diethyl-8-phenylxanthine greater than theophylline = caffeine (IC50 greater than 10,000 nM). Antagonist inhibition curves were steep and best described by a one-site binding model. In contrast, adenosine A1 agonist competition curves were shallow, as indicated by Hill coefficients less than unity. Computer analysis revealed that these inhibition curves were best described by a two-site binding model. Agonist competition curves generated in the presence of 1 mM GTP resulted in a rightward shift and steepening of the inhibition-concentration curves, whereas antagonist binding was not altered in the presence of GTP. The complex binding interactions found with adenosine agonists indicate that (3H)CGS 15943 labels both high and low affinity components of the adenosine A1 receptor in the rat cortex.

  18. Regulation of adenosine triphosphate-sensitive potassium channels suppresses the toxic effects of amyloid-beta peptide (25-35)

    Min Kong; Maowen Ba; Hui Liang; Peng Shao; Tianxia Yu; Ying Wang

    2013-01-01

    In this study, we treated PC12 cells with 0-20 μM amyloid-β peptide (25-35) for 24 hours to induce cytotoxicity, and found that 5-20 μM amyloid-β peptide (25-35) decreased PC12 cell viability, but adenosine triphosphate-sensitive potassium channel activator diazoxide suppressed the decrease reactive oxygen species levels. These protective effects were reversed by the selective mitochondrial adenosine triphosphate-sensitive potassium channel blocker 5-hydroxydecanoate. An inducible nitric oxide synthase inhibitor, Nω-nitro-L-arginine, also protected PC12 cells from intracellular reactive oxygen species levels. However, the H2O2-degrading enzyme catalase could that the increases in both mitochondrial membrane potential and reactive oxygen species levels adenosine triphosphate-sensitive potassium channels and nitric oxide. Regulation of adenosine triphosphate-sensitive potassium channels suppresses PC12 cell cytotoxicity induced by amyloid-β

  19. Protective effects of inhibition of adenosine monophosphate activated protein kinase activity against cerebral ischemia-reperfusion injury in mice

    补娟

    2013-01-01

    Objective To observe the effect of inhibition of adenosine monophosphate activated protein kinase (AMPK) on shape,function and inflammatory factor of microglia for mice after cerebral ischemia-reperfusion

  20. Cyclic adenosine monophosphate-dependent phosphorylation of mammalian mitochondrial proteins: enzyme and substrate characterization and functional role

    Dobrová, Zuzana; Sardanelli, A. M.; Speranza, F.; Scacco, S.; Signorile, A.; Lorusso, V.; Papa, S.

    2001-01-01

    Roč. 40, - (2001), s. 13941-13947. ISSN 0006-2960 Institutional research plan: CEZ:AV0Z5020903 Keywords : cAMP * cyclic adenosine monophosphate Subject RIV: CE - Biochemistry Impact factor: 4.114, year: 2001

  1. Impairment of ATP hydrolysis decreases adenosine A1 receptor tonus favoring cholinergic nerve hyperactivity in the obstructed human urinary bladder

    Silva-Ramos, M.; Silva, I; Faria, M.; Magalhães-Cardoso, M. T.; Correia, J.; Ferreirinha, F; Correia-de-Sá, P.

    2015-01-01

    This study was designed to investigate whether reduced adenosine formation linked to deficits in extracellular ATP hydrolysis by NTPDases contributes to detrusor neuromodulatory changes associated with bladder outlet obstruction in men with benign prostatic hyperplasia (BPH). The kinetics of ATP catabolism and adenosine formation as well as the role of P1 receptor agonists on muscle tension and nerve-evoked [3H]ACh release were evaluated in mucosal-denuded detrusor strips from BPH patients (n...

  2. Efficient, low-cost protein factories: expression of human adenosine deaminase in baculovirus-infected insect larvae.

    Medin, J A; Hunt, L; Gathy, K; Evans, R K; Coleman, M S

    1990-01-01

    Human adenosine deaminase (EC 3.5.4.4), a key purine salvage enzyme essential for immune competence, has been overproduced in Spodoptera frugiperda cells and in Trichoplusia ni (cabbage looper) larvae infected with recombinant baculovirus. The coding sequence of human adenosine deaminase was recombined into a baculovirus immediately downstream from the strong polyhedrin gene promoter. Approximately 60 hr after infection of insect cells with the recombinant virus, maximal levels of intracellul...

  3. Differential modulation of ATP-induced calcium signalling by A1 and A2 adenosine receptors in cultured cortical astrocytes

    Alloisio, Susanna; Cugnoli, Carlo; Ferroni, Stefano; Nobile, Mario

    2004-01-01

    Despite the accumulating evidence that under various pathological conditions the extracellular elevation of adenine-based nucleotides and nucleosides plays a key role in the control of astroglial reactivity, how these signalling molecules interact in the regulation of astrocyte function is still largely elusive.The action of the nucleoside adenosine in the modulation of the intracellular calcium signalling ([Ca2+]i) elicited by adenosine 5′-triphosphate (ATP)-induced activation of P2 purinoce...

  4. Nucleoside-Derived Antagonists to A3 Adenosine Receptors Lower Mouse Intraocular Pressure and Act across Species

    Wang, Zhao; Do, Chi Wai; Avila, Marcel Y.; Peterson-Yantorno, Kim; Stone, Richard A.; Gao, Zhan-Guo; Joshi, Bhalchandra; Besada, Pedro; Jeong, Lak Shin; Jacobson, Kenneth A.; Civan, Mortimer M.

    2009-01-01

    The purpose of the study was to determine whether novel, selective antagonists of human A3 adenosine receptors (ARs) derived from the A3-selective agonist Cl-IB-MECA lower intraocular pressure (IOP) and act across species. IOP was measured invasively with a micropipette by the Servo-Null Micropipette System (SNMS) and by non-invasive pneumotonometry during topical drug application. Antagonist efficacy was also assayed by measuring inhibition of adenosine-triggered shrinkage of native bovine n...

  5. Adenosine inhibitory effect on enhanced growth of aortic smooth muscle cells from streptozotocin-induced diabetic rats.

    Parés-Herbuté, N.; Hillaire-Buys, D.; Etienne, P.; Gross, R.; Loubatières-Mariani, M. M.; MONNIER, L.

    1996-01-01

    1. There is evidence to suggest that adenosine may regulate arterial smooth muscle cell (SMC) growth and proliferation, which is a key event in atherogenesis. This regulation may be mediated via adenylate cyclase. As diabetes is a known risk factor for atherosclerosis, we investigated the growth of aortic SMC from diabetic rats in primary culture and their sensitivity to adenosine and to adenylate cyclase activity. 2. Diabetes was induced with streptozotocin (STZ, 66 mg kg-1, i.p.) Aortic SMC...

  6. Sleep-Wake Regulation and Its Impact on Working Memory Performance: The Role of Adenosine

    Reichert, Carolin Franziska; Maire, Micheline; Schmidt, Christina; Cajochen, Christian

    2016-01-01

    The sleep-wake cycle is regulated by a fine-tuned interplay between sleep-homeostatic and circadian mechanisms. Compelling evidence suggests that adenosine plays an important role in mediating the increase of homeostatic sleep pressure during time spent awake and its decrease during sleep. Here, we summarize evidence that adenosinergic mechanisms regulate not only the dynamic of sleep pressure, but are also implicated in the interaction of homeostatic and circadian processes. We review how this interaction becomes evident at several levels, including electrophysiological data, neuroimaging studies and behavioral observations. Regarding complex human behavior, we particularly focus on sleep-wake regulatory influences on working memory performance and underlying brain activity, with a specific emphasis on the role of adenosine in this interplay. We conclude that a change in adenosinergic mechanisms, whether exogenous or endogenous, does not only impact on sleep-homeostatic processes, but also interferes with the circadian timing system. PMID:26861410

  7. Alteration of membrane phospholipid methylation by adenosine analogs does not affect T lymphocyte activation

    Membrane phospholipid methylation has been described during activation of various immune cells. Moreover recent data indicated modulation of immune cells functions by adenosine. As S-adenosyl-methionine and S-adenosyl-homocysteine are adenosine analogs and modulators of transmethylation reactions, the effects of SAH and SAM were investigated on membrane phospholipid methylation and lymphocyte activation. SAM was shown to induce the membrane phospholipid methylation as assessed by the 3Hmethyl-incorporation in membrane extract. This effect was inhibited by SAH. In contrast SAM and SAH did not affect the phytohemagglutinin-induced proliferative response of peripheral blood mononuclear cells. SAH neither modified the early internalization of membrane CD3 antigens nor did it prevent the late expression of HLA-DR antigens on lymphocytes activated by phytohemagglutinin. These results indicate that in vitro alteration of phospholipid methylation does not affect subsequent steps of human T lymphocyte activation and proliferation

  8. Platelet aggregation and serum adenosine deaminase (ADA) activity in pregnancy associated with diabetes, hypertension and HIV.

    Leal, Claudio A M; Leal, Daniela B R; Adefegha, Stephen A; Morsch, Vera M; da Silva, José E P; Rezer, João F P; Schrekker, Clarissa M L; Abdalla, Faida H; Schetinger, Maria R C

    2016-07-01

    Platelet aggregation and adenosine deaminase (ADA) activity were evaluated in pregnant women living with some disease conditions including hypertension, diabetes mellitus and human immunodeficiency virus infection. The subject population is consisted of 15 non-pregnant healthy women [control group (CG)], 15 women with normal pregnancy (NP), 7 women with hypertensive pregnancy (HP), 10 women with gestational diabetes mellitus (GDM) and 12 women with human immunodeficiency virus-infected pregnancy (HIP) groups. The aggregation of platelets was checked using an optical aggregometer, and serum ADA activity was determined using the colorimetric method. After the addition of 5 µM of agonist adenosine diphosphate, the percentage of platelet aggregation was significantly (p pregnancy and pregnancy-associated diseases suggest that platelet aggregation and ADA activity could serve as peripheral markers for the development of effective therapy in the maintenance of homeostasis and some inflammatory process in these pathophysiological conditions. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27273565

  9. Synthesis and Pharmacological Evaluation of Modified Adenosines Joined to Mono-Functional Platinum Moieties

    Stefano D'Errico

    2014-07-01

    Full Text Available The synthesis of four novel platinum complexes, bearing N6-(6-amino-hexyladenosine or a 1,6-di(adenosin-N6-yl-hexane respectively, as ligands of mono-functional cisplatin or monochloro(ethylendiamineplatinum(II, is reported. The chemistry exploits the high affinity of the charged platinum centres towards the N7 position of the adenosine base system and a primary amine of an alkyl chain installed on the C6 position of the purine. The cytotoxic behaviour of the synthesized complexes has been studied in A549 adenocarcinomic human alveolar basal epithelial and MCF7 human breast adenocarcinomic cancer cell lines, in order to investigate their effects on cell viability and proliferation.

  10. Tumour necrosis factor-α and adenosine in endotoxin shockleading related cardiovascular symptoms

    S. Sipka

    1995-01-01

    Full Text Available We have observed uncontrollable cardiogenic shock as a cardiovascular manifestation of systemic inflammatory response syndrome (SIRS leading to death in a 62-year-old woman. The diagnosis of SIRS was based on the demonstration of endotoxinaemia, and highly elevated plasma levels of tumour necrosis factor (TNF-α, and interleukin (IL-10. We suggest that these cytokines may contribute to the terminal SIRS-related arrythmias, impaired myocardial contractility, as well as increased vascular permeability. In addition, the increased production of adenosine, a counter-regulatory mediator of inflammation, may also play a role in cardiodepression. We suggest a relationship between the action of TNF-α , IL-10 and adenosine in the pathogenesis of circulatory symptoms described above.

  11. Interaction of Divalent Metal Ions with the Adenosine Triphosphate Measured Using Nuclear Magnetic Resonance

    2000-01-01

    The interaction of adenosine triphosphate with divalent metal ions is important in biochemical functions. The effects of pH and metal ions Mg2+, Ca2+, Zn2+, Mn2+, and Co2+ on the chemical shift of the phosphate group of ATP have been studied using Nuclear Magnetic Resonance. The chemical shift of the β-phosphate of ATP is the most sensitive to pH. Ca2+ and Mg2+ bind with the α- and β-phosphate groups of ATP. Zn2+ binds to the adenosine ring hydrogen as well as to phosphate. The paramagnetic ions Mn2+ and Co2+ do not cause chemical shifts of the phosphate or proton peak. Mn2+ and Co2+ broaden the resonance peak only.

  12. Adenosine kinase deficiency with neurodevelopemental delay and recurrent hepatic dysfunction: A case report

    Shakiba, Marjan; Mahjoub, Fatemeh; Fazilaty, Hassan; Rezagholizadeh, Fereshteh; Shakiba, Arghavan; Ziadlou, Maryam; Gahl, William A.; Behnam, Babak

    2016-01-01

    Hypermethioninemia may be benign, present as a nonspecific sign of nongenetic conditions such as liver failure and prematurity, or a severe, progressive inborn error of metabolism. Genetic causes of hypermethioninemia include mitochondrial depletion syndromes caused by mutations in the MPV17 and DGUOK genes and deficiencies of cystathionine β-synthase, methionine adenosyltransferase types I and III, glycine N-methyltransferase, S-adenosylhomocysteine hydrolase, citrin, fumarylacetoacetate hydrolase, and adenosine kinase. Here we present a 3-year old girl with a history of poor feeding, irritability, respiratory infections, cholestasis, congenital heart disease, neurodevelopmental delay, hypotonia, sparse hair, facial dysmorphisms, liver dysfunction, severe hypermethioninemia and mild homocystinemia. Genetic analysis of the adenosine kinase (ADK) gene revealed a previously unreported variant (c.479–480 GA>TG) resulting in a stop codon (p.E160X) in ADK. A methionine-restricted diet normalized the liver function test results and improved her hypotonia. PMID:27500280

  13. Thermodynamic studies on protonation constant of adenosine and guanosine at different temperatures and ionic strengths

    Highlights: • Protonation constants of adenosine and guanosine were determined. • The dependence of temperature and ionic strength were characterized. • Potentiometric and spectrophotometric methods were used. - Abstract: Stepwise protonation constants of two purine nucleosides (adenosine and guanosine) were determined at different temperatures (293.15 to 308.15) and various ionic strengths (0.101 to 3.503 mol · kg−1 NaClO4) using a combination of potentiometric and spectrophotometric method. The thermodynamic parameters (i.e. enthalpy change, ΔH, and entropy change, ΔS) of the protonations were calculated at different temperatures using van’t Hoff and virial equations. The dependence of the protonation constant on ionic strength is modeled by a Debye–Hückel type equation and discussed. Finally, the protonation constants of the nucleosides and the enthalpy change of protonations were determined at zero ionic strength

  14. Diagnostic value of domestic made adenosine in 99Tcm-MIBI myocardial perfusion SPECT for detecting coronary artery disease

    Objective: To evaluate the accuracy and safety of domestic made adenosine in 99Tcm- methoxyisobutylisonitrile (MIBI) myocardial perfusion SPECT during adenosine stress for the diagnosis of coronary ischemia. Methods: One hundred and two patients [73 men, 29 women, mean age (57 ± 10.4) years] with suspected coronary artery disease underwent adenosine stress and rest myocardial perfusion imaging. Adenosine was infused intravenously at a constant rate of 0.14 mg·kg-1·main-1 for 6 min. At the end of 3 min, 925 MBq of 99Tcm-MIBI was injected. In 70 patients coronary angiography was also performed within one week. Results: Thirty-nine patients had significant coronary artery stenosis and 31 patients had normal result. Adenosine stress myocardial perfusion scintigraphy was abnormal in 32 out of the 39 patients in coronary artery stenosis (sensitivity, 82.05%), and normal in 26 out of the 31 patients with normal angiography (specificity 83.87%). The positive and negative predictive values were 86.49% and 78.79% respectively. The frequency of side-effects was slight and transient with the incidence of 85.29%. Conclusion: The domestic made adenosine in stress myocardial perfusion imaging is safe and sensitive for detecting myocardial ischemia. (authors)

  15. Cellular mechanisms for the treatment of chronic heart failure: the nitric oxide- and adenosine-dependent pathways.

    Minamino, Tetsuo; Kitakaze, Masafumi

    2002-05-01

    Accumulated evidence suggests that several drugs proven to improve survival in patients with chronic heart failure (CHF) enhance endogenous nitric oxide (NO)- and/or adenosine-dependent pathways. Indeed, we and others have demonstrated that: i) antagonists of either renin-angiotensin-aldosterone or beta-adrenergic systems enhance NO-dependent pathways; ii) although carvedilol and amlodipine belong to different drug classes, both of them can increase cardiac adenosine levels; iii) increased adenosine levels by dipyridamole are associated with the improvement of CHF. Interestingly, both NO and adenosine have multifactorial beneficial actions in cardiovascular systems. First of all, both of them induce vasodilation and decrease myocardial hypercontractility, which may contribute to a reduction in the severity of myocardial ischaemia. Both adenosine and NO are also involved in cardioprotection attributable to acute and late phases of ischaemic preconditioning, respectively. Secondly, they can modulate the neurohormonal systems that contribute to the progression of CHF. Thus, we propose that enhancement of endogenous NO and/or adenosine as potential therapeutic targets in a new strategy for the treatment for CHF. PMID:15989539

  16. [Thallium-201 myocardial perfusion imaging during adenosine-induced coronary vasodilation in patients with ischemic heart disease].

    Takeishi, Y; Chiba, J; Abe, S; Ikeda, K; Tonooka, I; Komatani, A; Takahashi, K; Nakagawa, Y; Shiraishi, T; Tomoike, H

    1992-09-01

    201Tl myocardial perfusion imaging during adenosine infusion was performed in consecutive 55 patients with suspected coronary artery disease. Adenosine was infused intravenously at a rate of 0.14 mg/kg/min for 6 minutes and a dose of 111 MBq of 201Tl was administered in a separate vein at the end of third minute of infusion. Myocardial SPECT imaging was begun 5 minutes and 3 hours after the end of adenosine infusion. For evaluating the presence of perfusion defects, 2 short axis images at the basal and apical levels and a vertical long axis image at the mid left ventricle were used. The regions with decreased 201Tl uptake were assessed semi-quantitatively. Adenosine infusion caused a slight reduction in systolic blood pressure and an increase in heart rate. The rate pressure products increased slightly (9314 +/- 2377 vs. 10360 +/- 2148, p < 0.001). Chest pain (24%) and headache (13%) were the frequent side effects. The second-degree atrioventricular block was developed in 11 of 55 (20%) patients. All symptoms and hemodynamic changes were well tolerated and disappeared within 1 or 2 minutes after discontinuing adenosine infusion. The sensitivity and specificity for the detection of patients with coronary artery disease were 100% (31/31) and 88% (7/8), respectively. 201Tl myocardial imaging during adenosine infusion was considered to be safe and useful for evaluating the patients with ischemic heart disease. PMID:1453559

  17. Effect of 2-(6-cyano-1-hexyn-1-yl)adenosine on ocular blood flow in rabbits.

    Konno, Takashi; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Nakahata, Norimichi

    2007-02-27

    Previously, we reported that a relatively selective adenosine A(2A) receptor agonist 2-(6-cyano-1-hexyn-1-yl)adenosine (2-CN-Ado) elicited ocular hypotension in rabbits (Journal of Pharmacological Sciences 2005;97:501-509). In the present study, we investigated the effect of 2-CN-Ado on ocular blood flow in rabbit eyes. An intravitreal injection of 2-CN-Ado increased ocular blood flow, measured by a non-contact laser flowmeter. 2-CN-Ado-induced increase in ocular blood flow was accompanied with the retinal vasodilation. The increase in ocular blood flow was inhibited by an adenosine A(2A) receptor antagonist 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine, but not by an adenosine A(2B) receptor antagonist alloxazine or an adenosine A(1) receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine. The repetitive applications of topical 2-CN-Ado twice a day for 7 days produced a persistent increase in ocular blood flow with ocular hypotension. These results suggest that 2-CN-Ado increases the ocular blood flow mainly via adenosine A(2A) receptor, and that the topical application of 2-CN-Ado for several days not only increases the ocular blood flow but also prolong ocular hypotension, indicating that 2-CN-Ado may be a useful lead compound for the treatment of ischemic retinal diseases such as glaucoma. PMID:17239401

  18. Comparison of adenosine and exercise stress 201Tl myocardial perfusion imaging for diagnosing coronary heart disease in women

    Objective: To compare the diagnostic value of adenosine and exercise stress myocardial perfusion imaging (MPI) for detecting coronary heart disease (CHD) in women. Methods: One hundred and thirty-eight patients with CHD were randomly divided into two groups: adenosine stress group (n=69)and exercise stress group (n=69). All patients underwent myocardial SPECT evaluation. Coronary angiography (CAG), referred as 'gold standard' , was performed in each patient within 1 week before or after MPI. The diagnostic value of the two stress MPI was compared with χ2 test or Fisher's exact test. Results: In adenosine stress group, the sensitivity, negative predictive value and accuracy were 88.2% (45/51), 72.7% (16/22), 88.4% (61/69), respectively, which were not significantly different from those of the exercise stress group (91.7% (44/48), 66.7% (8/12), 81.2% (52/64); χ2 =0.571, 0.714, 0.249, P>0.05). However, the false positive rate of adenosine stress (11.1%, 2/18) was significantly lower than that of exercise stress (50.0%, 8/16), P=0.023. Conclusions: Adenosine and exercise stress MPI have similar value for CHD diagnosis in women, however, adenosine stress MPI may have an advantage of low false positive rate. (authors)

  19. Evaluation of myocardial blood supply using adenosine stress myocardial perfusion imaging

    Objective: To retrospectively evaluate the value and accuracy of adenosine stress and rest SPECT myocardial perfusion imaging. Methods: A total of 1858 patients who were suspected or known for coronary artery disease (CAD) underwent 99Tcm-methoxyisobutylisonitrile (MIBI) myocardial perfusion SPECT with adenosine infusion using the standard 2-day protocol. Images were interpreted by two or more experienced nuclear medicine physicians. Coronary angiography was carried out in all patients within one month. Kappa test was used to analyze the correlation between the two imaging studies. Results: By coronary angiography, there were 957 patients diagnosed of CAD (one-, two-, three-vessel disease: 506, 256, 195, respectively) and 901 normal. Stenosis was found in 1603 vessels, including left anterior descending coronary artery (LAD): 765, left circumflex coronary artery (LCX): 399 and right coronary artery (RCA): 439. By adenosine induced stress myocardial perfusion imaging, 876 patients were diagnosed of myocardial ischemia (sensitivity: 876/957, 91.54%) and 651 patients had negative findings (specificity: 651/901,72.25 %). The positive and negative predictive values were 77.80% (876/1126) and 88.93% (651/732), respectively. The correlation coefficient between the two imaging studies was 0.641. The vessel-based sensitivity was 81.31% (622/765) for LAD, 56.64% (226/399) for LCX and 70.62% (310/439) for RCA, respectively. The sensitivity for detection of one-, two-, three-vessel stenosis was 87.55% (443/506), 94.92% (243/256) and 97.44% (190/195), respectively. The side-effects was mild and transient with an incidence rate of 84.12% (1563/1858), without major cardiac events. Conclusion: Stress myocardial perfusion imaging induced by adenosine is reliable for the evaluation of myocardial blood supply in CAD patients. (authors)

  20. Molecular Pathways of Disturbed Sleep and Depression: Studies on Adenosine and Gene Expression Patterns

    Gass, Natalia

    2010-01-01

    Background: Adenosine is a potent sleep-promoting substance, and one of its targets is the basal forebrain. Fairly little is known about its mechanism of action in the basal forebrain and about the receptor subtype mediating its regulating effects on sleep homeostasis. Homeostatic deficiency might be one of the causes of the profoundly disturbed sleep pattern in major depressive disorder, which could explain the reduced amounts of delta-activity-rich stages 3 and 4. Since major depression has...

  1. Adenosine receptors in the immature brain : with special reference to their role in hypoxic ischemia

    Ådén, Ulrika

    2001-01-01

    Although the newborn brain tolerates a much longer period of oxygen deprivation and ischemia than does the adult brain, perinatal hypoxic ischemia probably is an important cause of neurological dysfunction, cerebral palsy and epilepsy later in life. Hence it is important to investigate the mechanisms that modulate the extent of perinatal ischernic brain damage. There is good evidence that endogenous adenosine acts as a neuroprotective agent in models of ischemia in the m...

  2. Adenosine kinase inhibition protects against cranial radiation-induced cognitive dysfunction

    Munjal M Acharya

    2016-06-01

    Full Text Available Clinical radiation therapy for the treatment of CNS cancers leads to unintended and debilitating impairments in cognition. Radiation-induced cognitive dysfunction is long lasting, however, the underlying molecular and cellular mechanisms are still not well established. Since ionizing radiation causes microglial and astroglial activation, we hypothesized that maladaptive changes in astrocyte function might be implicated in radiation-induced cognitive dysfunction. Among other gliotransmitters, astrocytes control the availability of adenosine, an endogenous neuroprotectant and modulator of cognition, via metabolic clearance through adenosine kinase (ADK. Adult rats exposed to cranial irradiation (10 Gy showed significant declines in performance of hippocampal-dependent cognitive function tasks (novel place recognition, novel object recognition, and contextual fear conditioning 1 month after exposure to ionizing radiation using a clinically relevant regimen. Irradiated rats spent less time exploring a novel place or object. Cranial irradiation also led to reduction in freezing behavior compared to controls in the fear conditioning task. Importantly, immunohistochemical analyses of irradiated brains showed significant elevation of ADK immunoreactivity in the hippocampus that was related to astrogliosis and increased expression of glial fibrillary acidic protein (GFAP. Conversely, rats treated with the ADK inhibitor 5-iodotubercidin (5-ITU, 3.1 mg/kg, i.p., for 6 days prior to cranial irradiation showed significantly improved behavioral performance in all cognitive tasks 1 month post exposure. Treatment with 5-ITU attenuated radiation-induced astrogliosis and elevated ADK immunoreactivity in the hippocampus. These results confirm an astrocyte-mediated mechanism where preservation of extracellular adenosine can exert neuroprotection also against radiation-induced pathology. These innovative findings link radiation-induced changes in cognition and CNS

  3. Adenosine: front and center in linking nutrition and metabolism to neuronal activity

    Greene, Robert W

    2011-01-01

    Many individuals with epilepsy benefit from consuming a ketogenic diet, which is similar to the more commonly known Atkins diet. The underlying molecular reason for this has not been determined. However, in this issue of the JCI, Masino et al. have elucidated the mechanism responsible for the antiepileptic effects of the ketogenic diet in mice. The diet is shown to decrease expression of the enzyme adenosine kinase (Adk), which is responsible for clearing the endogenous antiepileptic agent ad...

  4. A Review of Tandem Mass Spectrometry Characterization of Adenosine Diphosphate-Ribosylated Peptides

    Hengel, Shawna M.; Goodlett, David R.

    2011-01-01

    The use of tandem mass spectrometry to identify and characterize sites of protein adenosine diphosphate (ADP) ribosylation will be reviewed. Specifically, we will focus on data acquisition schemes and fragmentation techniques that provide peptide sequence and modification site information. Also discussed are uses of synthetic standards to aid characterization, and an enzymatic method that converts ADP-ribosylated peptides into ribosyl mono phosphorylated peptides making identification amenabl...

  5. Adenosine Preconditioning versus Ischemic Preconditioning in Patients undergoing Off-Pump Coronary Artery Bypass (OPCAB

    SeyedKhalil Forouzannia

    2015-10-01

    Full Text Available Background: During off-pump coronary artery bypass (OPCAB, the heart is subjected to ischemic and reperfusion injury. Preconditioning is a mechanism that permits the heart to tolerate myocardial ischemia. The aim of this study was to compare the effects of Adenosine preconditioning with ischemic preconditioning on the global ejection fraction (EF in patients undergoing OPCAB.Methods: In this single-blind, randomized controlled trial, sixty patients undergoing OPCAB were allocated into three equally-numbered groups through simple randomization: Adenosine group, ischemic group, and control group. The patients in the Adenosine group received an infusion of Adenosine. In the ischemic group, ischemic preconditioning was induced by the temporary occlusion of the left anterior descending coronary artery twice for a 2-minute period, followed by 3-minute reperfusion before bypass grafting of the first coronary vessel. The control group received an intravenous infusion of 0.9% saline. Blood samples at different times were sent for the measurement of creatine kinase isoenzyme MB (CK-MB and cardiac troponin I (cTnI. We also recorded electrocardiographic indices and clinical parameters, including postoperative use of inotropic drugs and preoperative and postoperative EF.Results: History of myocardial infarction, hyperlipidemia, diabetes mellitus, kidney disease, preoperative arrhythmias, and utilization of postoperative inotrope was the same between the three groups. The incidence of postoperative arrhythmias was not significant between the three groups. Also, there were no significant differences in preoperative and postoperative EF and the serum levels of enzymes (cTnI and CK-MB between the groups.Conclusion: Based on the findings of this study, there was no significant difference in the postoperative EF between the groups. Although the incidence of arrhythmias was higher in the ischemic preconditioning group than in the other groups, the difference

  6. Autoimmune dysregulation and purine metabolism in adenosine deaminase (ADA)-deficiency

    Aisha Vanessa Sauer; Immacolata eBrigida; Nicola eCarriglio; Alessandro eAiuti

    2012-01-01

    Genetic defects in the adenosine deaminase (ADA) gene are among the most common causes for severe combined immunodeficiency (SCID). ADA-SCID patients suffer from lymphopenia, severely impaired cellular and humoral immunity, failure to thrive and recurrent infections. Currently available therapeutic options for this otherwise fatal disorder include bone marrow transplantation (BMT), enzyme replacement therapy with bovine ADA (PEG-ADA) or hematopoietic stem cell gene therapy (HSC-GT). Although ...

  7. Role of adenosine receptor agonists in pharmacological modulation of myelosuppression induced by ionizing radiation

    Hofer, Michal; Pospíšil, Milan; Holá, Jiřina; Vacek, Antonín; Štreitová, Denisa

    Buenos Aires, 2008. s. 1-7. [IRPA 12 - 12th International Congress of the International Radiation Protection Association - Strengthening Radiation Protection Worldwide. 19.10.2008-24.10.2008, Buenos Aires] R&D Projects: GA ČR(CZ) GA305/06/0015; GA ČR(CZ) GA305/08/0158 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : adenosine receptors * hematopoiesis * radiation-induced myelosuppression Subject RIV: BO - Biophysics

  8. Cordyceps pruinosa produces cordycepin and N6-(2-hydroxyethyl)-adenosine in culture

    Meng Zebin; Wen Tingchi; Kang Jichuan; Lei Bangxing; Hyde Kevin D.

    2014-01-01

    Cordyceps species are entomophagous pathogens with medicinal properties, mostly linked to cordycepin and N6- (2-hydroxyethyl)-adenosine (HEA). An isolate of Cordyceps pruinosa (GZUCC 8552) was obtained from a fruiting body formed on the cocoon a Limacodidae insect collected in Guizhou Province, China. Morphological and molecular analysis (combined 5.8S ITS, RPB1 and 18S RNA) confirmed the species to be Cordyceps pruinosa. Metabolites of the isolate grown in...

  9. Serum adenosine deaminase as oxidative stress marker in type 2 diabetes mellitus

    Shashikala Magadi Dasegowda; Ashok Kumar Jeppu; Sushith; Kavitha Ashok Kumar

    2015-01-01

    Background: Oxidative stress markers are increased in type 2 diabetes mellitus and its estimation helps in predicting the long term complications. In present study comparison and correlation of the levels of serum adenosine deaminase, serum malondialdehyde, and serum total antioxidant capacity in type 2 diabetes mellitus and in age and sex matched healthy controls. Methods: Study group consisted of 100 individuals between the age group of 35-65 years of age. Of which 50 individuals with t...

  10. Thyroid expression of an A2 adenosine receptor transgene induces thyroid hyperplasia and hyperthyroidism.

    Ledent, C; Dumont, J E; Vassart, G.; Parmentier, M

    1992-01-01

    Cyclic AMP (cAMP) is the major intracellular second messenger of thyrotropin (TSH) action on thyroid cells. It stimulates growth as well as the function and differentiation of cultured thyrocytes. The adenosine A2 receptor, which activates adenylyl cyclase via coupling to the stimulating G protein (Gs), has been shown to promote constitutive activation of the cAMP cascade when transfected into various cell types. In order to test whether the A2 receptor was able to function similarly in vivo ...

  11. Contribution of adenosine to compensatory dilation in hypoperfused contracting human muscles is independent of nitric oxide

    Casey, Darren P.; Joyner, Michael J.

    2011-01-01

    We previously demonstrated that nitric oxide (NO) contributes to compensatory vasodilation in the contracting human forearm subjected to acute hypoperfusion. We examined the potential role of an adenosine-NO interaction to this response in 17 male subjects (25 ± 2 yr). In separate protocols subjects performed rhythmic forearm exercise (20% of maximum) while hypoperfusion was evoked by balloon inflation in the brachial artery above the elbow. Each trial included exercise before inflation, exer...

  12. Respiratory activity in medulla oblongata and its modulation by adenosine and opioids

    Herlenius, Eric

    1998-01-01

    From the moment of birth the complex neuronal networks generating breathing has to function continuously and adapt to the new postnatal environmental demands. This thesis aims at studying the perinatal development of respiratory control and its modulation by adenosine and opioids. Respiratory activity was studied in vitro using brainstem spinal cord preparations and in vivo with a barometric plethysmograph. In vitro whole-cell patch clamp recordings of respiratory related ne...

  13. Cyclic adenosine monophosphate is a key component of regulatory T cell–mediated suppression

    Bopp, Tobias; Becker, Christian; Klein, Matthias; Klein-Heßling, Stefan; Palmetshofer, Alois; Serfling, Edgar; Heib, Valeska; Becker, Marc; Kubach, Jan; Schmitt, Steffen; Stoll, Sabine; Schild, Hansjörg; Staege, Martin S.; Stassen, Michael; Jonuleit, Helmut

    2007-01-01

    Naturally occurring regulatory T cells (T reg cells) are a thymus-derived subset of T cells, which are crucial for the maintenance of peripheral tolerance by controlling potentially autoreactive T cells. However, the underlying molecular mechanisms of this strictly cell contact–dependent process are still elusive. Here we show that naturally occurring T reg cells harbor high levels of cyclic adenosine monophosphate (cAMP). This second messenger is known to be a potent inhibitor of proliferati...

  14. Impairment of skeletal muscle adenosine triphosphate–sensitive K+ channels in patients with hypokalemic periodic paralysis

    Tricarico, Domenico; Servidei, Serenella; Tonali, Pietro; Jurkat-Rott, Karin; Camerino, Diana Conte

    1999-01-01

    The adenosine triphosphate (ATP)–sensitive K+ (KATP) channel is the most abundant K+ channel active in the skeletal muscle fibers of humans and animals. In the present work, we demonstrate the involvement of the muscular KATP channel in a skeletal muscle disorder known as hypokalemic periodic paralysis (HOPP), which is caused by mutations of the dihydropyridine receptor of the Ca2+ channel. Muscle biopsies excised from three patients with HOPP carrying the R528H mutation of the dihydropyridin...

  15. Adenosine activates brown adipose tissue and recruits beige adipocytes via A2A receptors

    Gnad, Thorsten; Scheibler, Saskia; von Kügelgen, Ivar;

    2014-01-01

    Brown adipose tissue (BAT) is specialized in energy expenditure, making it a potential target for anti-obesity therapies. Following exposure to cold, BAT is activated by the sympathetic nervous system with concomitant release of catecholamines and activation of β-adrenergic receptors. Because BAT...... that adenosine-A2A signalling plays an unexpected physiological role in sympathetic BAT activation and protects mice from diet-induced obesity. Those findings reveal new possibilities for developing novel obesity therapies....

  16. Photophysical processes of the spectroscopic RNA probe 2-(1-ethynylpyrene-adenosine (PyA

    Engels J.

    2013-03-01

    Full Text Available We examine the photoinduced excited state dynamics of pyrene modified adenosine, a versatile probe for folding and hybridization of ribonucleic acids. Measurements in different solvents revealed complex ultrafast dynamics, but high robustness since the overall fluorescence quantum yield (Φf is hardly affected. The result is a strong fluorescent RNA-probe whose spectral properties change in a defined way upon environmental changes.

  17. Possible regulation of the Salmonella typhimurium histidine operon by adenosine triphosphate phosphoribosyltransferase: large metabolic effects.

    Goitein, R K; Parsons, S. M.

    1980-01-01

    An effort to find growth conditions leading to conditional regulation of the histidine operon of Salmonella typhimurium by the allosteric first enzyme of the pathway, adenosine triphosphate phosphoribosyltransferase (EC 2.4.2.17), is reported. A strain deleting the enzyme, TR3343, behaved simply and predictably under all growth conditions, whereas histidine auxotrophs containing active enzyme behaved in complicated ways dependent upon the location of the histidine pathway lesion. hisE strains...

  18. Inhibition of adenosine deaminase (ADA)-mediated metabolism of cordycepin by natural substances

    Li, Gen; Nakagome, Izumi; Hirono, Shuichi; Itoh, Tomoo; Fujiwara, Ryoichi

    2015-01-01

    Cordycepin, which is an analogue of a nucleoside adenosine, exhibits a wide variety of pharmacological activities including anticancer effects. In this study, ADA1- and ADA2-expressing HEK293 cells were established to determine the major ADA isoform responsible for the deamination of cordycepin. While the metabolic rate of cordycepin deamination was similar between ADA2-expressing and Mock cells, extensive metabolism of cordycepin was observed in the ADA1-expressing cells with K m and V max v...

  19. The effects of adenosine on plasma homocysteine levels and some other biochemical parameters

    Turgut, Günfer; Rota, Simin; Aybek, Hülya; Turgut, Sebahat; Sert, Seelahattin; Genç, Osman

    2009-01-01

    Süleyman Demirel Üniversitesi TIP FAKÜLTESİ DERGİSİ: 2007 Aralık; 14(4) The effects of adenosine on plasma homocysteine levels and some other biochemical parameters Günfer Turgut*, Simin Rota**, Hülya Aybek**, Sebahat Turgut*, Selahattin Sert**, Osman Genç* *Pamukkale University Faculty of Medicine Departments of Physiology, Denizli, Turkey **Pamukkale University,Faculty of Medicine, Departments of Biochemistry Denizl...

  20. The in vivo respiratory phenotype of the adenosine A1 receptor knockout mouse.

    Heitzmann, Dirk; Buehler, Philipp; Schweda, Frank; Georgieff, Michael; Warth, Richard; Thomas, Joerg

    2016-02-01

    The nucleoside adenosine has been implicated in the regulation of respiration, especially during hypoxia in the newborn. In this study the role of adenosine A1 receptors for the control of respiration was investigated in vivo. To this end, respiration of unrestrained adult and neonatal adenosine A1 receptor knockout mice (A1R(-/-)) was measured in a plethysmographic device. Under control conditions (21% O2) and mild hypoxia (12-15% O2) no difference of respiratory parameters was observed between adult wildtype (A1R(+/+)) and A1R(-/-) mice. Under more severe hypoxia (6-10% O2) A1R(+/+) mice showed, after a transient increase of respiration, a decrease of respiration frequency (fR) and tidal volume (VT) leading to a decrease of minute volume (MV). This depression of respiration during severe hypoxia was absent in A1R(-/-) mice which displayed a stimulated respiration as indicated by the enhancement of MV by some 50-60%. During hypercapnia-hyperoxia (3-10% CO2/97-90 % O2), no obvious differences in respiration of A1R(-/-) and A1R(+/+) was observed. In neonatal mice, the respiratory response to hypoxia was surprisingly similar in both genotypes. However, neonatal A1R(-/-) mice appeared to have more frequently periods of apnea during hypoxia and in the post-hypoxic control period. In conclusion, these data indicate that the adenosine A1 receptor is an important molecular component mediating hypoxic depression in adult mice and it appears to stabilize respiration of neonatal mice. PMID:26593641

  1. Development of gene therapy: potential in severe combined immunodeficiency due to adenosine deaminase deficiency.

    Montiel-Equihua, Claudia A; Thrasher, Adrian J.; Bobby Gaspar, H

    2009-01-01

    Claudia A Montiel-Equihua, Adrian J Thrasher, H Bobby GasparCentre for Immunodeficiency, Molecular Immunology Unit, UCL Institute of Child Health, London, UKAbstract: The history of stem cell gene therapy is strongly linked to the development of gene therapy for severe combined immunodeficiencies (SCID) and especially adenosine deaminase (ADA)-deficient SCID. Here we discuss the developments achieved in over two decades of clinical and laboratory research that led to the establishment of a pr...

  2. Development of gene therapy: potential in severe combined immunodeficiency due to adenosine deaminase deficiency

    Thrasher, Adrian

    2009-01-01

    Claudia A Montiel-Equihua, Adrian J Thrasher, H Bobby GasparCentre for Immunodeficiency, Molecular Immunology Unit, UCL Institute of Child Health, London, UKAbstract: The history of stem cell gene therapy is strongly linked to the development of gene therapy for severe combined immunodeficiencies (SCID) and especially adenosine deaminase (ADA)-deficient SCID. Here we discuss the developments achieved in over two decades of clinical and laboratory research that led to the establishment of a pr...

  3. SIGNIFICANCE OF ADENOSINE DEAMINASE SERUM CONCENTRATIONS IN THE DIAGNOSIS OF EXTRA-PULMONARY TUBERCULOSIS

    Stevanovic G.; Pelemis M.; Pavlovic M.; Lavadinovic L,; Dakic Z,; Milosevic I,; Milosevic B.

    2011-01-01

    Extra pulmonary tuberculosis (EPTB) is a growing problem worldwide. Due to the nature of the disease, the diversity of clinical pictures as well as its minor epidemiological importance, the diagnosis is difficult and often late.In addition to standard TB diagnostic techniques use of new biochemical (surrogate markers) are increased. With this work we wanted to examine the usefulness of serum adenosine deaminase levels as a diagnostic parameter for EPTB.The work included 116 patients with feve...

  4. Biosynthesis of bacterial glycogen: activator specificity of the adenosine diphosphate glucose pyrophosphorylases from the genus Rhodospirillum.

    Preiss, J; Greenberg, E

    1981-01-01

    The adenosine diphosphate (ADP) glucose pyrophosphorylases from Rhodospirillum fulvum, Rhodospirillum molischianum, and Rhodospirillum tenue were partially purified, and their kinetic properties were studied. The enzyme from the three organisms was found to be activated by pyruvate and thus was similar to the Rhodospirillum rubrum enzyme that had been previously studied (C. E. Furlong, and J. Preiss, J. Biol. Chem. 244:2539-2548, 1979). The enzymes from R. fulvum, R. molischianum, and R. tenu...

  5. Pulmonary Vascular Capacitance as a Predictor of Vasoreactivity in Idiopathic Pulmonary Arterial Hypertension Tested by Adenosine

    Shafie, Davood; Dohaei, Abolfazl; AMIN, Ahmad; Taghavi, Sepideh; Naderi, Nasim

    2015-01-01

    Background: Acute pulmonary vasoreactivity testing has been recommended in the diagnostic work-up of patients with idiopathic pulmonary arterial hypertension (IPAH). Pulmonary arteriolar capacitance (Cp) approximated by stroke volume divided by pulmonary pulse pressure (SV/PP) is considered as an independent predictor of mortality in patients with IPAH. Objectives: We sought to evaluate any differences in baseline and adenosine Cp between vasoreactive and non-vasoreactive IPAH patients tested...

  6. The effect of ticlopidine administration to humans on the binding of adenosine diphosphate to blood platelets

    Lips, J.P.M.; Sixma, J.J.; Schiphorst, M.E.

    1980-01-01

    Administration of Ticlopidine to human volunteers resulted in a prolonged bleeding time and decreased or absent aggregation of platelets with collagen and epinephrine. Adenosine diphosphate (ADP) induced platelet aggregation was initiated by a normal shape change, but the rate of the first wave of aggregation had decreased. The second wave of aggregation was absent. ADP-binding to platelets of volunteers, consisted of two classes of binding sites:one with high affinity and one with low affini...

  7. CD73-mediated adenosine production promotes stem cell-like properties in mouse Tc17 cells.

    Flores-Santibáñez, Felipe; Fernández, Dominique; Meza, Daniel; Tejón, Gabriela; Vargas, Leonardo; Varela-Nallar, Lorena; Arredondo, Sebastián; Guixé, Victoria; Rosemblatt, Mario; Bono, María Rosa; Sauma, Daniela

    2015-12-01

    The CD73 ectonucleotidase catalyses the hydrolysis of AMP to adenosine, an immunosuppressive molecule. Recent evidence has demonstrated that this ectonucleotidase is up-regulated in T helper type 17 cells when generated in the presence of transforming growth factor-β (TGF-β), and hence CD73 expression is related to the acquisition of immunosuppressive potential by these cells. TGF-β is also able to induce CD73 expression in CD8(+) T cells but the function of this ectonucleotidase in CD8(+) T cells is still unknown. Here, we show that Tc17 cells present high levels of the CD73 ectonucleotidase and produce adenosine; however, they do not suppress the proliferation of CD4(+) T cells. Interestingly, we report that adenosine signalling through A2A receptor favours interleukin-17 production and the expression of stem cell-associated transcription factors such as tcf-7 and lef-1 but restrains the acquisition of Tc1-related effector molecules such as interferon-γ and Granzyme B by Tc17 cells. Within the tumour microenvironment, CD73 is highly expressed in CD62L(+) CD127(+) CD8(+) T cells (memory T cells) and is down-regulated in GZMB(+) KLRG1(+) CD8(+) T cells (terminally differentiated T cells), demonstrating that CD73 is expressed in memory/naive cells and is down-regulated during differentiation. These data reveal a novel function of CD73 ectonucleotidase in arresting CD8(+) T-cell differentiation and support the idea that CD73-driven adenosine production by Tc17 cells may promote stem cell-like properties in Tc17 cells. PMID:26331349

  8. Outcome of Patients With Adenosine-Induced ST Segment Depression and Normal Myocardial Perfusion

    The aim of the present study was to determine the outcome of patients with normal MPS and adenosine-induced ST segment depression. A total of 1867 patients underwent adenosine Tc99m-tetrofosmin MPS in nuclear medicine unit in Saudi German Hospital, Saudi Arabia, between January 2004 and May 2008. Their ECGs were checked for ST segment depression during adenosine infusion. All patients with ≥ 1 mm horizontal or down-sloping ST segment depression or≥ 1.5 mm up-sloping ST segment depression were included in the study. Fifty-six patients met our inclusion criteria, of which 45 (80%) were females. During the follow-up period, a total of 15 of patients ended up doing coronary angiography, either for high clinical suspicion or following a second positive MPS performed 6-18 months after the first study. Seven of them were positive for coronary artery disease and were subsequently treated with revascularization procedure, and 8 returned either normal angiography or non-obstructive coronary artery disease. Male diabetic smoking patients were more prevalent and underwent revascularization. The patients were followed up for a mean of 22.8 ±7.8 months. No cardiac deaths or myocardial infarctions were reported. It could be concluded that adenosine-induced ST segment depression in patients with normal myocardial perfusion was a benign finding and did not increase the very low risk of cardiac events in those patients. However, male smokers and/or diabetics might need further investigation. This suggestion needs further evaluation

  9. Dyspnea and Wheezing after Adenosine Injection in a Patient with Eosinophilic Bronchitis

    Kaiser Lim; Marie Christine Aubry; Rodrigo Cartin-Ceba

    2009-01-01

    A 58-year-old nonsmoker female was referred for evaluation of chronic cough of 13 months duration. After an initial work-up, the patient was diagnosed to have chronic cough due to eosinophilic bronchitis. The diagnostic work-up for eosinophilic bronchitis and bronchial biopsy is discussed. Eosinophilic bronchitis is differentiated from asthma. In addition, the patient developed dyspnea, flushing, and wheezing after the administration of adenosine during a cardiac stress test in spite of a neg...

  10. Cordycepin Increases Nonrapid Eye Movement Sleep via Adenosine Receptors in Rats

    Zhenzhen Hu

    2013-01-01

    Full Text Available Cordycepin (3′-deoxyadenosine is a naturally occurring adenosine analogue and one of the bioactive constituents isolated from Cordyceps militaris/Cordyceps sinensis, species of the fungal genus Cordyceps. It has traditionally been a prized Chinese folk medicine for the human well-being. Because of similarity of chemical structure of adenosine, cordycepin has been focused on the diverse effects of the central nervous systems (CNSs, like sleep regulation. Therefore, this study was undertaken to know whether cordycepin increases the natural sleep in rats, and its effect is mediated by adenosine receptors (ARs. Sleep was recorded using electroencephalogram (EEG for 4 hours after oral administration of cordycepin in rats. Sleep architecture and EEG power spectra were analyzed. Cordycepin reduced sleep-wake cycles and increased nonrapid eye movement (NREM sleep. Interestingly, cordycepin increased θ (theta waves power density during NREM sleep. In addition, the protein levels of AR subtypes (A1, A2A, and A2B were increased after the administration of cordycepin, especially in the rat hypothalamus which plays an important role in sleep regulation. Therefore, we suggest that cordycepin increases theta waves power density during NREM sleep via nonspecific AR in rats. In addition, this experiment can provide basic evidence that cordycepin may be helpful for sleep-disturbed subjects.

  11. 99Tcm-MIBI adenosine myocardial perfusion imaging in patients with slow coronary flow

    Objective: To investigate the relationship between myocardial ischemia and slow coronary flow phenomenon with 99Tcm-methoxyisobutylisonitrile (MIBI) adenosine myocardial perfusion SPECT imaging. Methods: Forty-four patients were divided to three groups according to the result of coronary angiography (CAG). There were GAG-positive (P-GAG) (n=12), slow coronary flow (CSF) (n =22), and normal coronary flow (NCF) (n = 10). Results: of adenosine myocardial perfusion imaging were compared among these three groups. Semi-quantitative visual scoring method was used to evaluate the myocardial perfusion: 0 = normal,1 = mild decrease, 2 = moderate decrease, 3 = severe decrease, 4 = defect. Statistical analysis was performed using variance analysis, t-test and χ2-test. Results: No significance was observed at age (t =0.27, 0.54 and 0.59), sex (χ2 = 0.92), hypertension, hyperlipemia and diabetes (χ2 = 1.23, all P>0.05) among the three groups. A significantly higher frames of the coronary thrombolysis in myocardial infarction (TIMI) flow was noted in CSF than in NCF groups (33.7±5.5 vs 17.6±3.9, t = 9.58, P0.05). Conclusion: Slow coronary flow phenomenon can be detected by adenosine myocardial perfusion image to offer the evidence of diagnosis and treatment for the chest pain patients with negative coronary angiography results. (authors)

  12. Voltammetric determination of adenosine and guanosine using fullerene-C(60)-modified glassy carbon electrode.

    Goyal, Rajendra N; Gupta, Vinod K; Oyama, Munetaka; Bachheti, Neeta

    2007-02-28

    A fullerene-C(60)-modified glassy carbon electrode (GCE) is used for the simultaneous determination of adenosine and guanosine by differential pulse voltammetry. Compared to a bare glassy carbon electrode, the modified electrode exhibits an apparent shift of the oxidation potentials in the cathodic direction and a marked enhancement in the voltammetric peak current response for both the biomolecules. Linear calibration curves are obtained over the concentration range 0.5muM-1.0mM in 0.1M phosphate buffer solution at pH 7.2 with a detection limit of 3.02x10(-7)M and 1.45x10(-7)M for individual determination of adenosine and guanosine, respectively. The interference studies showed that the fullerene-C(60)-modified glassy carbon electrode exhibited excellent selectivity in the presence of hypoxanthine, xanthine, uric acid and ascorbic acid. The proposed procedure was successfully applied to detect adenosine and guanosine in human blood plasma and urine, without any preliminary pre-treatment. PMID:19071420

  13. Thyroid expression of an A2 adenosine receptor transgene induces thyroid hyperplasia and hyperthyroidism.

    Ledent, C; Dumont, J E; Vassart, G; Parmentier, M

    1992-02-01

    Cyclic AMP (cAMP) is the major intracellular second messenger of thyrotropin (TSH) action on thyroid cells. It stimulates growth as well as the function and differentiation of cultured thyrocytes. The adenosine A2 receptor, which activates adenylyl cyclase via coupling to the stimulating G protein (Gs), has been shown to promote constitutive activation of the cAMP cascade when transfected into various cell types. In order to test whether the A2 receptor was able to function similarly in vivo and to investigate the possible consequences of permanent adenylyl cyclase activation in thyroid cells, lines of transgenic mice were generated expressing the canine A2 adenosine receptor under control of the bovine thyroglobulin gene promoter. Thyroid-specific expression of the A2 adenosine receptor transgene promoted gland hyperplasia and severe hyperthyroidism causing premature death of the animals. The resulting goitre represents a model of hyperfunctioning adenomas: it demonstrates that constitutive activation of the cAMP cascade in such differentiated epithelial cells is sufficient to stimulate autonomous and uncontrolled function and growth. PMID:1371462

  14. Reduced striatal ecto-nucleotidase activity in schizophrenia patients supports the "adenosine hypothesis".

    Aliagas, Elisabet; Villar-Menéndez, Izaskun; Sévigny, Jean; Roca, Mercedes; Romeu, Miriam; Ferrer, Isidre; Martín-Satué, Mireia; Barrachina, Marta

    2013-12-01

    Schizophrenia (SZ) is a major chronic neuropsychiatric disorder characterized by a hyperdopaminergic state. The hypoadenosinergic hypothesis proposes that reduced extracellular adenosine levels contribute to dopamine D2 receptor hyperactivity. ATP, through the action of ecto-nucleotidases, constitutes a main source of extracellular adenosine. In the present study, we examined the activity of ecto-nucleotidases (NTPDases, ecto-5'-nucleotidase, and alkaline phosphatase) in the postmortem putamen of SZ patients (n = 13) compared with aged-matched controls (n = 10). We firstly demonstrated, by means of artificial postmortem delay experiments, that ecto-nucleotidase activity in human brains was stable up to 24 h, indicating the reliability of this tissue for these enzyme determinations. Remarkably, NTPDase-attributable activity (both ATPase and ADPase) was found to be reduced in SZ patients, while ecto-5'-nucleotidase and alkaline phosphatase activity remained unchanged. In the present study, we also describe the localization of these ecto-enzymes in human putamen control samples, showing differential expression in blood vessels, neurons, and glial cells. In conclusion, reduced striatal NTPDase activity may contribute to the pathophysiology of SZ, and it represents a potential mechanism of adenosine signalling impairment in this illness. PMID:23771238

  15. 2-Aminopyrimidines as dual adenosine A1/A2A antagonists.

    Robinson, Sarel J; Petzer, Jacobus P; Terre'Blanche, Gisella; Petzer, Anél; van der Walt, Mietha M; Bergh, Jacobus J; Lourens, Anna C U

    2015-11-01

    In this study thirteen 2-aminopyrimidine derivatives were synthesised and screened as potential antagonists of adenosine A1 and A2A receptors in order to further investigate the structure activity relationships of this class of compounds. 4-(5-Methylfuran-2-yl)-6-[3-(piperidine-1-carbonyl)phenyl]pyrimidin-2-amine (8m) was identified as a compound with high affinities for both receptors, with an A2AKi value of 6.34 nM and an A1Ki value of 9.54 nM. The effect of selected compounds on the viability of cultured cells was assessed and preliminary results indicate low cytotoxicity. In vivo efficacy at A2A receptors was illustrated for compounds 8k and 8m since these compounds attenuated haloperidol-induced catalepsy in rats. A molecular docking study revealed that the interactions between the synthesised compounds and the adenosine A2A binding site most likely involve Phe168 and Asn253, interactions which are similar for structurally related adenosine A2A receptor antagonists. PMID:26462195

  16. Extracellular nucleotide catabolism in human B and T lymphocytes. The source of adenosine production

    Extracellular nucleotide degradation was studied in intact human B and T lymphocyte subpopulations and in lymphoblastoid cell lines. Cells of B lymphocyte lineage showed high nucleotide degrading activity, whereas T lymphocytes were unable to degrade extracellular nucleotides. The external surface of B cells contained active sites of ecto-triphosphonucleotidase (ecto-ATPase), ecto-diphosphonucleotidase (ecto-ADPase), and ecto-monophosphonucleotidase (ecto-AMPase). The expression of all three ectoenzyme activities seemed closely associated with B cell development. ATPase and ADPase activities increase continuously during B cell maturation, ecto-AMPase activity, on the other hand, reaches maximal activity in late pre-B cells. These results combined with our previous studies of intracellular ATP catabolism provide evidence that extracellular ATP catabolism may represent exclusive source for adenosine in lymphocytes. It is suggested that adenosine may serve as a means of communication between B and T cells in lymphoid organs, B lymphocytes being the sole producers of adenosine and T lymphocytes being the recipients of this signal

  17. Cerebral A1 adenosine receptors (A1AR) in liver cirrhosis

    The cerebral mechanisms underlying hepatic encephalopathy (HE) are poorly understood. Adenosine, a neuromodulator that pre- and postsynaptically modulates neuronal excitability and release of classical neurotransmitters via A1 adenosine receptors (A1AR), is likely to be involved. The present study investigates changes of cerebral A1AR binding in cirrhotic patients by means of positron emission tomography (PET) and [18F]CPFPX, a novel selective A1AR antagonist. PET was performed in cirrhotic patients (n = 10) and healthy volunteers (n = 10). Quantification of in vivo receptor density was done by Logan's non-invasive graphical analysis (pons as reference region). The outcome parameter was the apparent binding potential (aBP, proportional to Bmax/KD). Cortical and subcortical regions showed lower A1AR binding in cirrhotic patients than in controls. The aBP changes reached statistical significance vs healthy controls (p 1AR binding may further aggravate neurotransmitter imbalance at the synaptic cleft in cirrhosis and hepatic encephalopathy. Different pathomechanisms may account for these alterations including decrease of A1AR density or affinity, as well as blockade of the A1AR by endogenous adenosine or exogenous xanthines. (orig.)

  18. Role of adipokinetic hormone and adenosine in the anti-stress response in Drosophila melanogaster.

    Zemanová, Milada; Stašková, Tereza; Kodrík, Dalibor

    2016-01-01

    The role of adipokinetic hormone (AKH) and adenosine in the anti-stress response was studied in Drosophila melanogaster larvae and adults carrying a mutation in the Akh gene (Akh(1)), the adenosine receptor gene (AdoR(1)), or in both of these genes (Akh(1) AdoR(1) double mutant). Stress was induced by starvation or by the addition of an oxidative stressor paraquat (PQ) to food. Mortality tests revealed that the Akh(1) mutant was the most resistant to starvation, while the AdoR(1) mutant was the most sensitive. Conversely, the Akh(1) AdoR(1) double mutant was more sensitive to PQ toxicity than either of the single mutants. Administration of PQ significantly increased the Drome-AKH level in w(1118) and AdoR(1) larvae; however, this was not accompanied by a simultaneous increase in Akh gene expression. In contrast, PQ significantly increased the expression of the glutathione S-transferase D1 (GstD1) gene. The presence of both a functional adenosine receptor and AKH seem to be important for the proper control of GstD1 gene expression under oxidative stress, however, the latter appears to play more dominant role. On the other hand, differences in glutathione S-transferase (GST) activity among the strains, and between untreated and PQ-treated groups were minimal. In addition, the glutathione level was significantly lower in all untreated AKH- or AdoR-deficient mutant flies as compared with the untreated control w(1118) flies and further declined following treatment with PQ. All oxidative stress characteristics modified by mutations in Akh gene were restored or even improved by 'rescue' mutation in flies which ectopically express Akh. Thus, the results of the present study demonstrate the important roles of AKH and adenosine in the anti-stress response elicited by PQ in a D. melanogaster model, and provide the first evidence for the involvement of adenosine in the anti-oxidative stress response in insects. PMID:27374982

  19. Mixed Inhibition of Adenosine Deaminase Activity by 1,3-Dinitrobenzene: A Model for Understanding Cell-Selective Neurotoxicity in Chemically-Induced Energy Deprivation Syndromes in Brain

    Wang, Yipei; Liu, Xin; Schneider, Brandon; Zverina, Elaina A.; Russ, Kristen; Wijeyesakere, Sanjeeva J.; Fierke, Carol A.; Richardson., Rudy J.; Philbert, Martin A.

    2011-01-01

    Astrocytes are acutely sensitive to 1,3-dinitrobenzene (1,3-DNB) while adjacent neurons are relatively unaffected, consistent with other chemically-induced energy deprivation syndromes. Previous studies have investigated the role of astrocytes in protecting neurons from hypoxia and chemical injury via adenosine release. Adenosine is considered neuroprotective, but it is rapidly removed by extracellular deaminases such as adenosine deaminase (ADA). The present study tested the hypothesis that ...

  20. Effects of AMP579 and adenosine on L-type Ca2+ current in isolated rat ventricular myocytes

    Xiong WANG; Bo-wei WU; Dong-mei WU

    2005-01-01

    Aim: To compare the effects of AMP579 and adenosine on L-type Ca2+ current (ICa- L) in rat ventricular myocytes and explore the mechanism by which AMP579 acts on ICa-L. Methods: ICa-L was recorded by patch-clamp technique in whole-cell configuration. Results: Adenosine (10 nmol/L to 50 μmol/L) showed no effect on basal ICa- L, but it inhibited the ICa-L induced by isoproterenol 10 nmol/L in a concen tration-dependent manner with the IC50 of 13.06 μmol/L. Similar to adenosine,AMP579 also showed an inhibitory effect on the ICa-L induced by isoproterenol.AMP579 and adenosine (both in 10 μmol/L) suppressed isoproterenol-induced ICa-L by 11.1% and 5.2%, respectively. In addition, AMP579 had a direct inhibitory effect on basal ICa-L in a concentration-dependent manner with IC50 (1.17 μmol/L).PD116948 (30 μmol/L), an adenosine A1 receptor blocker, showed no action on the inhibitory effect of AMP579 on basal ICa-L. However, GF109203X (0.4 μmol/L), a special protein kinase C (PKC) blocker, could abolish the inhibitory effect of AMP579 on basal ICa-L. So the inhibitory effect of AMP579 on basal ICa-L was induced through activating PKC, but not linked to adenosine A1 receptor. Conclusion:AMP579 shows a stronger inhibitory effect than adenosine on the ICa-L induced by isoproterenol. AMP579 also has a strong inhibitory effect on basal ICa-L in rat ventricular myocytes. Activation of PKC is involved in the inhibitory effect of AMP579 on basal ICa-L at downstream-mechanism.

  1. Pooled comparison of regadenoson versus adenosine for measuring fractional flow reserve and coronary flow in the catheterization laboratory

    Background: Adenosine is the gold standard for augmenting coronary flow during fractional flow reserve (FFR) testing of intermediate coronary stenoses. However, intravenous infusion is time-consuming and intracoronary injection is subject to variability. Regadenoson is a newer adenosine alternative administered as a single intravenous bolus during nuclear stress testing, but its efficacy and safety during FFR testing have been evaluated only in small, single-center studies. Methods: We pooled data from 5 academic hospitals, in which patients undergoing clinically-indicated FFR prospectively underwent comparison of intravenous adenosine infusion (140–175 mcg/kg/min) versus regadenoson bolus (400 mcg). Hemodynamics and symptoms with adenosine were recorded until maximal hyperemia occurred, and after returning to baseline hemodynamics, regadenoson was administered and monitoring was repeated. In a subset of patients with coronary flow data, average peak velocity (APV) at the distal flow sensor was recorded. Results: Of 149 patients enrolled, mean age was 59 ± 9 years, 76% were male, and 54% underwent testing of the left anterior descending artery. Mean adenosine-FFR and regadenoson-FFR were identical (0.82 ± 0.10) with excellent correlation of individual values (r = 0.96, p < 0.001) and no difference in patient-reported symptoms. Four patients (2.6%) had discrepancies between the 2 drugs for the clinical decision-making cutoff of FFR ≤ 0.80. Coronary flow responses to adenosine and regadenoson were similar (APV at maximal hyperemia 36 cm/s for both, p = 0.81). Conclusions: Regadenoson single-bolus administration has comparable FFR, symptoms, and coronary flow augmentation when compared with standard intravenous adenosine infusion. With its greater ease of administration, regadenoson may be a more “user-friendly” option for invasive ischemic testing

  2. The comparison of two gated SPET protocols: adenosine Tc-99m tetrafosmin and treadmill exercise Tc-99m MIBI

    The effect of adenosine and exercise on gated SPET left ventricular ejection fraction (LVEF), end diastolic volume (EDV) and end systolic volume (ESV) has not been fully investigated. The aim of the study was to compare functional measurements obtained in one-day adenosine rest and two-day stress-rest protocols in relation to ischaemia. Out of 226 consecutive patients examined with submaximal treadmill stress-rest 700 MBq Tc-99m MIBI, 26 were chosen to match those subjected to adenosine (140 μg/kg/min) enhanced by a low level exercise protocol (300 MBq and 700 MBq Tc-99m tetrofosmin for stress and rest respectively). All images were acquired on a double head system and were gated using 8 frames, 25 s per frame. ED and ES volumes increased after adenosine but decreased after treadmill resulting in the post-stress LVEF being significantly greater than after adenosine, 60 ± 11 v. 51 ± 13% (p < 0.01). This was caused by the smaller post-stress ESV in the treadmill group 40 ± 20 v. 51 ± 34, p < 0.05. In non-ischaemic scans the LVEF was greater (61± 8 v. 51 ± 14, p < 0.01) and EDV and ESV smaller after both stress and rest. The adenosine test may have an opposite influence on the EDV and ESV in comparison to the submaximal treadmill test and therefore the left ventricular function measurements after adenosine infusion should be interpreted carefully and may not represent those acquired after physical exercise. In the gated SPET scans showing ischaemia the post-stress EDV and ESV may be greater and the LVEF lower than at rest. (author)

  3. Pooled comparison of regadenoson versus adenosine for measuring fractional flow reserve and coronary flow in the catheterization laboratory

    Stolker, Joshua M., E-mail: jstolker@yahoo.com [Mercy Heart and Vascular, 901 Patients First Drive, Washington, MO 63090 (United States); Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Lim, Michael J., E-mail: limmj@slu.edu [Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Shavelle, David M., E-mail: david.shavelle@med.usc.edu [University of Southern California, 1510 San Pablo St, Suite 322, Los Angeles, CA 90033 (United States); Morris, D. Lynn, E-mail: morrisdl@einstein.edu [Albert Einstein Medical Center, 5501 Old York Rd, Philadelphia, PA 19141 (United States); Angiolillo, Dominick J., E-mail: dominick.angiolillo@jax.ufl.edu [University of Florida Health-Jacksonville, 655 West 8th St, Jacksonville, FL 32209 (United States); Guzman, Luis A., E-mail: luis.guzman@jax.ufl.edu [University of Florida Health-Jacksonville, 655 West 8th St, Jacksonville, FL 32209 (United States); Kennedy, Kevin F., E-mail: kfkennedy@saint-lukes.org [Saint Luke' s Mid America Heart Institute, 4401 Wornall Road, Kansas City, MO 64111 (United States); Weber, Elizabeth, E-mail: eweber1@slu.edu [Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Zareh, Meena, E-mail: meena.zareh@med.usc.edu [University of Southern California, 1510 San Pablo St, Suite 322, Los Angeles, CA 90033 (United States); Neumayr, Robert H., E-mail: robneumayr@gmail.com [Mercy Heart and Vascular, 901 Patients First Drive, Washington, MO 63090 (United States); Saint Louis University, 3635 Vista Ave, St. Louis, MO 63110 (United States); Zenni, Martin M., E-mail: martin.zenni@jax.ufl.edu [University of Florida Health-Jacksonville, 655 West 8th St, Jacksonville, FL 32209 (United States)

    2015-07-15

    Background: Adenosine is the gold standard for augmenting coronary flow during fractional flow reserve (FFR) testing of intermediate coronary stenoses. However, intravenous infusion is time-consuming and intracoronary injection is subject to variability. Regadenoson is a newer adenosine alternative administered as a single intravenous bolus during nuclear stress testing, but its efficacy and safety during FFR testing have been evaluated only in small, single-center studies. Methods: We pooled data from 5 academic hospitals, in which patients undergoing clinically-indicated FFR prospectively underwent comparison of intravenous adenosine infusion (140–175 mcg/kg/min) versus regadenoson bolus (400 mcg). Hemodynamics and symptoms with adenosine were recorded until maximal hyperemia occurred, and after returning to baseline hemodynamics, regadenoson was administered and monitoring was repeated. In a subset of patients with coronary flow data, average peak velocity (APV) at the distal flow sensor was recorded. Results: Of 149 patients enrolled, mean age was 59 ± 9 years, 76% were male, and 54% underwent testing of the left anterior descending artery. Mean adenosine-FFR and regadenoson-FFR were identical (0.82 ± 0.10) with excellent correlation of individual values (r = 0.96, p < 0.001) and no difference in patient-reported symptoms. Four patients (2.6%) had discrepancies between the 2 drugs for the clinical decision-making cutoff of FFR ≤ 0.80. Coronary flow responses to adenosine and regadenoson were similar (APV at maximal hyperemia 36 cm/s for both, p = 0.81). Conclusions: Regadenoson single-bolus administration has comparable FFR, symptoms, and coronary flow augmentation when compared with standard intravenous adenosine infusion. With its greater ease of administration, regadenoson may be a more “user-friendly” option for invasive ischemic testing.

  4. Plasma concentrations of the cyclic nucleotides, adenosine 3',5'-monophosphate and guanosine 3'.5'-monophosphate, in healthy adults treated with theophylline

    Fenger, M; Eriksen, P B; Andersen, O;

    1982-01-01

    Plasma concentrations of cyclic adenosine monophosphate and cyclic guanosine monophosphate were measured in 10 health adults before, during and after periods of theophylline administration. Cyclic adenosine monophosphate concentrations did not change significantly, but cyclic guanosine monophosph......Plasma concentrations of cyclic adenosine monophosphate and cyclic guanosine monophosphate were measured in 10 health adults before, during and after periods of theophylline administration. Cyclic adenosine monophosphate concentrations did not change significantly, but cyclic guanosine...... monophosphate concentrations decreased by 29% on average when theophylline was administered. The change in cyclic guanosine monophosphate was not correlated to the plasma concentration of theophylline in the range studied....

  5. Basal and adenosine receptor-stimulated levels of cAMP are reduced in lymphocytes from alcoholic patients

    Alcoholism causes serious neurologic disease that may be due, in part, to the ability of ethanol to interact with neural cell membranes and change neuronal function. Adenosine receptors are membrane-bound proteins that appear to mediate some of the effects of ethanol in the brain. Human lymphocytes also have adenosine receptors, and their activation causes increases in cAMP levels. To test the hypothesis that basal and adenosine receptor-stimulated cAMP levels in lymphocytes might be abnormal in alcoholism, the authors studied lymphocytes from 10 alcoholic subjects, 10 age- and sex-matched normal individuals, and 10 patients with nonalcoholic liver disease. Basal and adenosine receptor-stimulated cAMP levels were reduced 75% in lymphocytes from alcoholic subjects. Also, there was a 76% reduction in ethanol stimulation of cAMP accumulation in lymphocytes from alcoholics. Similar results were demonstrable in isolated T cells. Unlike other laboratory tests examined, these measurements appeared to distinguish alcoholics from normal subjects and from patients with nonalcoholic liver disease. Reduced basal and adenosine receptor-stimulated levels of cAMP in lymphocytes from alcoholics may reflect a change in cell membranes due either to chronic alcohol abuse or to a genetic predisposition unique to alcoholic subjects

  6. Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

    Shimada, Kazuhiro; Yoshida, Katsuya [Chiba Univ. (Japan). School of Medicine; Tadokoro, Hiroyuki [and others

    2000-12-01

    The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg{center_dot}kg{sup -1}{center_dot}min{sup -1}) in 8 WHHL rabbits (13.8{+-}0.5 months) with {sup 13}N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml{center_dot}min{sup -1}{center_dot}g{sup -1}) did not differ significantly between control and WHHL groups both at baseline (3.67{+-}0.72 vs 4.26{+-}1.12 ml{center_dot}min{sup -1}{center_dot}g{sup -1}, p=NS) and with adenosine (7.92{+-}2.00 vs 9.27{+-}2.91 ml{center_dot}min{sup -1}{center_dot}g{sup -1}, p=NS), nor did coronary flow reserve (2.16{+-}0.37 vs 2.18{+-}0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model. (author)

  7. Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

    The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg·kg-1·min-1) in 8 WHHL rabbits (13.8±0.5 months) with 13N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml·min-1·g-1) did not differ significantly between control and WHHL groups both at baseline (3.67±0.72 vs 4.26±1.12 ml·min-1·g-1, p=NS) and with adenosine (7.92±2.00 vs 9.27±2.91 ml·min-1·g-1, p=NS), nor did coronary flow reserve (2.16±0.37 vs 2.18±0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model. (author)

  8. Comparison of adenosine-induced myocardial ischemia and atherosclerosis measured by coronary calcium tomography

    Coronary artery calcium shows a anatomic information and coronary atherosclerotic burde, but myocardial perfusion SPECT shows a physiologic significance of coronary stenosis and stress induced ischemia. Both are valuable in the noninvasive assessment of patients with suspected coronary artery disease. There has been little evaluation regarding the relationship between CAC and adenosine-induced ischemia and how to integrate CAC with myocardial perfusion SPECT. We assessed the relationship between adenosine-induced myocardial ischemia on myocardial perfusion single-photon emission computed tomography (MPS) and magnitude of coronary calcification (CAC) by MDCT in patients undergoing both tests. A total of 111 patients underwent adenosine-induced MPS and CAC within 2days. Coronary angiography was done in 55 patients. The frequency of ischemia by MPS was compared to the magnitude of CAC. Among 56 patients with ischemic MPS, the CAC scores were >0 in 87.5%, >100 in 76.8%, and > 400 in 50.0%. Of 25 normal MPS, the CAC scores were >0 in 70.9%. >100 in 34.5%, and > 400 in 14.5%, respectively. Of 38 patient with coronary artery stenosis proved by coronary angiography, the CAC scores were >0 in 92.1%, >100 in 78.9%, and > 400 in 50.0 %, respectively. Of 12 patient without coronary artery stenosis, the CAC scores were >100 in 66.7%, and > 400 in 41.7%. Ischemic MPS is associated with a high likelihood of subclinical atherosclerosis by CAC, but it can be also seen for CAC scores <100. The patient without significant coronary artery stenosis, however, may have extensive atherosclerosis by CAC criteria. Although, low CAC scores appear to obviate the need for subsequent testing, but MPS is still needed to diagnosis the myocardial ischemia

  9. Investigation into effects of antipsychotics on ectonucleotidase and adenosine deaminase in zebrafish brain.

    Seibt, Kelly Juliana; Oliveira, Renata da Luz; Bogo, Mauricio Reis; Senger, Mario Roberto; Bonan, Carla Denise

    2015-12-01

    Antipsychotic agents are used for the treatment of psychotic symptoms in patients with several brain disorders, such as schizophrenia. Atypical and typical antipsychotics differ regarding their clinical and side-effects profile. Haloperidol is a representative typical antipsychotic drug and has potent dopamine receptor antagonistic functions; however, atypical antipsychotics have been developed and characterized an important advance in the treatment of schizophrenia and other psychotic disorders. Purine nucleotides and nucleosides, such as ATP and adenosine, constitute a ubiquitous class of extracellular signaling molecules crucial for normal functioning of the nervous system. Indirect findings suggest that changes in the purinergic system, more specifically in adenosinergic activity, could be involved in the pathophysiology of schizophrenia. We investigated the effects of typical and atypical antipsychotics on ectonucleotidase and adenosine deaminase (ADA) activities, followed by an analysis of gene expression patterns in zebrafish brain. Haloperidol treatment (9 µM) was able to decrease ATP hydrolysis (35%), whereas there were no changes in hydrolysis of ADP and AMP in brain membranes after antipsychotic exposure. Adenosine deamination in membrane fractions was inhibited (38%) after haloperidol treatment when compared to the control; however, no changes were observed in ADA soluble fractions after haloperidol exposure. Sulpiride (250 µM) and olanzapine (100 µM) did not alter ectonucleotidase and ADA activities. Haloperidol also led to a decrease in entpd2_mq, entpd3 and adal mRNA transcripts. These findings demonstrate that haloperidol is an inhibitor of NTPDase and ADA activities in zebrafish brain, suggesting that purinergic signaling may also be a target of pharmacological effects promoted by this drug. PMID:26156500

  10. Cerebral A{sub 1} adenosine receptors (A{sub 1}AR) in liver cirrhosis

    Boy, Christian [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); University Hospital Essen, Department of Nuclear Medicine, Essen (Germany); Meyer, Philipp T. [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Kircheis, Gerald; Haussinger, Dieter [University of Duesseldorf, Clinic for Gastroenterology, Hepatology and Infectiology, Duesseldorf (Germany); Holschbach, Marcus H.; Coenen, Heinz H. [Research Centre Juelich, Institute of Nuclear Chemistry, Juelich (Germany); Herzog, Hans; Elmenhorst, David [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); Kaiser, Hans J. [University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Zilles, Karl [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); C. and O. Vogt Institute of Brain Research, Duesseldorf (Germany); Bauer, Andreas [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); University of Duesseldorf, Department of Neurology, Duesseldorf (Germany)

    2008-03-15

    The cerebral mechanisms underlying hepatic encephalopathy (HE) are poorly understood. Adenosine, a neuromodulator that pre- and postsynaptically modulates neuronal excitability and release of classical neurotransmitters via A{sub 1} adenosine receptors (A{sub 1}AR), is likely to be involved. The present study investigates changes of cerebral A{sub 1}AR binding in cirrhotic patients by means of positron emission tomography (PET) and [{sup 18}F]CPFPX, a novel selective A{sub 1}AR antagonist. PET was performed in cirrhotic patients (n = 10) and healthy volunteers (n = 10). Quantification of in vivo receptor density was done by Logan's non-invasive graphical analysis (pons as reference region). The outcome parameter was the apparent binding potential (aBP, proportional to B{sub max}/K{sub D}). Cortical and subcortical regions showed lower A{sub 1}AR binding in cirrhotic patients than in controls. The aBP changes reached statistical significance vs healthy controls (p < 0.05, U test with Bonferroni-Holm adjustment for multiple comparisons) in cingulate cortex (-50.0%), precentral gyrus (-40.9%), postcentral gyrus (-38.6%), insular cortex (-38.6%), thalamus (-32.9%), parietal cortex (-31.7%), frontal cortex (-28.6), lateral temporal cortex (-28.2%), orbitofrontal cortex (-27.9%), occipital cortex (-24.6), putamen (-22.7%) and mesial temporal lobe (-22.4%). Regional cerebral adenosinergic neuromodulation is heterogeneously altered in cirrhotic patients. The decrease of cerebral A{sub 1}AR binding may further aggravate neurotransmitter imbalance at the synaptic cleft in cirrhosis and hepatic encephalopathy. Different pathomechanisms may account for these alterations including decrease of A{sub 1}AR density or affinity, as well as blockade of the A{sub 1}AR by endogenous adenosine or exogenous xanthines. (orig.)

  11. No effect of nutritional adenosine receptor antagonists on exercise performance in the heat.

    Cheuvront, Samuel N; Ely, Brett R; Kenefick, Robert W; Michniak-Kohn, Bozena B; Rood, Jennifer C; Sawka, Michael N

    2009-02-01

    Nutritional adenosine receptor antagonists can enhance endurance exercise performance in temperate environments, but their efficacy during heat stress is not well understood. This double-blinded, placebo-controlled study compared the effects of an acute dose of caffeine or quercetin on endurance exercise performance during compensable heat stress (40 degrees C, 20-30% rh). On each of three occasions, 10 healthy men each performed 30-min of cycle ergometry at 50% Vo2peak followed by a 15-min performance time trial after receiving either placebo (Group P), caffeine (Group C; 9 mg/kg), or quercetin (Group Q; 2,000 mg). Serial blood samples, physiological (heart rate, rectal, and mean skin body temperatures), perceptual (ratings of perceived exertion, pain, thermal comfort, motivation), and exercise performance measures (total work and pacing strategy) were made. Supplementation with caffeine and quercetin increased preexercise blood concentrations of caffeine (55.62 +/- 4.77 microM) and quercetin (4.76 +/- 2.56 microM) above their in vitro inhibition constants for adenosine receptors. No treatment effects were observed for any physiological or perceptual measures, with the exception of elevated rectal body temperatures (0.20-0.30 degrees C; P affect total work performed (Groups P: 153.5 +/- 28.3, C: 157.3 +/- 28.9, and Q: 151.1 +/- 31.6 kJ; P > 0.05) or the self-selected pacing strategy employed. These findings indicate that the nutritional adenosine receptor antagonists caffeine and quercetin do not enhance endurance exercise performance during compensable heat stress. PMID:19020291

  12. Extracellular Adenosine Protects against Streptococcus pneumoniae Lung Infection by Regulating Pulmonary Neutrophil Recruitment.

    Bou Ghanem, Elsa N; Clark, Stacie; Roggensack, Sara E; McIver, Sally R; Alcaide, Pilar; Haydon, Philip G; Leong, John M

    2015-08-01

    An important determinant of disease following Streptococcus pneumoniae (pneumococcus) lung infection is pulmonary inflammation mediated by polymorphonuclear leukocytes (PMNs). We found that upon intratracheal challenge of mice, recruitment of PMNs into the lungs within the first 3 hours coincided with decreased pulmonary pneumococci, whereas large numbers of pulmonary PMNs beyond 12 hours correlated with a greater bacterial burden. Indeed, mice that survived infection largely resolved inflammation by 72 hours, and PMN depletion at peak infiltration, i.e. 18 hours post-infection, lowered bacterial numbers and enhanced survival. We investigated host signaling pathways that influence both pneumococcus clearance and pulmonary inflammation. Pharmacologic inhibition and/or genetic ablation of enzymes that generate extracellular adenosine (EAD) (e.g. the ectoenzyme CD73) or degrade EAD (e.g. adenosine deaminase) revealed that EAD dramatically increases murine resistance to S. pneumoniae lung infection. Moreover, adenosine diminished PMN movement across endothelial monolayers in vitro, and although inhibition or deficiency of CD73 had no discernible impact on PMN recruitment within the first 6 hours after intratracheal inoculation of mice, these measures enhanced PMN numbers in the pulmonary interstitium after 18 hours of infection, culminating in dramatically elevated numbers of pulmonary PMNs at three days post-infection. When assessed at this time point, CD73-/- mice displayed increased levels of cellular factors that promote leukocyte migration, such as CXCL2 chemokine in the murine lung, as well as CXCR2 and β-2 integrin on the surface of pulmonary PMNs. The enhanced pneumococcal susceptibility of CD73-/- mice was significantly reversed by PMN depletion following infection, suggesting that EAD-mediated resistance is largely mediated by its effects on PMNs. Finally, CD73-inhibition diminished the ability of PMNs to kill pneumococci in vitro, suggesting that EAD alters

  13. A2B Adenosine Receptor Agonist Improves Erectile Function in Diabetic Rats.

    Wen, Jiaming; Wang, Bohan; Du, Chuanjun; Xu, Gang; Zhang, Zhewei; Li, Yi; Zhang, Nan

    2015-01-01

    Diabetes is an important risk factor for erectile dysfunction (ED). Recent studies have indicated that A2B adenosine receptor (ADORA2B) signaling is essential for penile erection. Thus, we hypothesize that diabetic ED may be attributed to impaired A2B adenosine signaling. To test this hypothesis, we generated diabetic rats by injecting streptozocin as animal model. After 12 weeks, immunohistochemistry staining was used to localize the expression of ADORA2B. Western Blot and quantitative PCR were employed to determine ADORA2B expression level. Intracavernosal pressure (ICP) measurement was used to evaluate erectile function. Diabetic rats received a single intravenous injection of BAY 60-6583, an ADORA2B agonist, or vehicle solution, at 60 min before the ICP measurement. The results showed that ADORA2B expressed in the nerve bundle, smooth muscle, and endothelium in penile tissue of control mice. Western Blot and quantitative PCR results indicated that the expression levels of ADORA2B protein and mRNA were significantly reduced in penile tissues of diabetic rats. Functional studies showed that the erectile response induced by electrical stimulation was remarkably decreased in diabetic rats, compared with age-matched control rats. However, at 60 min after BAY 60-6583 treatment, the erectile function was improved in diabetic rats, suggesting that enhancement of ADORA2B signaling may improve erectile function in diabetic ED. This preclinical study has revealed a previously unrecognized therapeutic possibility of BAY 60-6583 as an effective and mechanism-based drug to treat diabetic ED. In conclusion, we propose that impaired A2B adenosine signaling is one of the pathological mechanisms of diabetic ED. PMID:26447087

  14. Adenosine induces cell cycle arrest and apoptosis via cyclinD1/Cdk4 and Bcl-2/Bax pathways in human ovarian cancer cell line OVCAR-3.

    Shirali, Saeid; Aghaei, Mahmoud; Shabani, Mahdi; Fathi, Mojtaba; Sohrabi, Majid; Moeinifard, Marzieh

    2013-04-01

    Adenosine is a regulatory molecule with widespread physiological effects in almost every cells and acts as a potent regulator of cell growth. Adenosine has been shown to inhibit cell growth and induce apoptosis in the several cancer cells via caspase activation and Bcl-2/Bax pathway. The present study was designed to understand the mechanism underlying adenosine-induced apoptosis in the OVCAR-3 human ovarian cancer cells. MTT viability, BrdU and cell counting assays were used to study the cell proliferation effect of adenosine in presence of adenosine deaminase inhibitor and the nucleoside transporter inhibitor. Cell cycle analysis, propidium iodide and annexin V staining, caspase-3 activity assay, cyclinD1, Cdk4, Bcl-2 and Bax protein expressions were assessed to detect apoptosis. Adenosine significantly inhibited cell proliferation in a concentration-dependent manner in OVCAR-3 cell line. Adenosine induced cell cycle arrest in G0/G1 phase via Cdk4/cyclinD1-mediated pathway. Adenosine induced apoptosis, which was determined by Annexin V-FITC staining and increased sub-G1 population. Moreover, down-regulation of Bcl-2 protein expression, up-regulation of Bax protein expression and activation of caspase-3 were observed in response to adenosine treatment. The results of this study suggest that extracellular adenosine induced G1 cell cycle arrest and apoptosis in ovarian cancer cells via cyclinD1/ Cdk4 and Bcl-2/Bax pathways and caspase-3 activation. These data might suggest that adenosine could be used as an agent for the treatment of ovarian cancer. PMID:23345014

  15. Hyperalgesia, anxiety, and decreased hypoxic neuroprotection in mice lacking the adenosine A1 receptor

    Johansson, Björn; Halldner, Linda; Dunwiddie, Thomas V.; Masino, Susan A.; Poelchen, Wolfgang; Giménez-Llort, Lydia; Escorihuela, Rosa M.; Fernández-Teruel, Alberto; Wiesenfeld-Hallin, Zsuzsanna; Xu, Xiao-Jun; Hårdemark, Anna; Betsholtz, Christer; Herlenius, Eric; Fredholm, Bertil B

    2001-01-01

    Caffeine is believed to act by blocking adenosine A1 and A2A receptors (A1R, A2AR), indicating that some A1 receptors are tonically activated. We generated mice with a targeted disruption of the second coding exon of the A1R (A1R−/−). These animals bred and gained weight normally and had a normal heart rate, blood pressure, and body temperature. In most behavioral tests they were similar to A1R+/+ mice, but A1R−/− mice showed signs of increased anxiety. Electrophysiological recordings from hi...

  16. Adenosine receptors in rat and human pancreatic ducts stimulate chloride transport

    Novak, Ivana; Hede, Susanne; Hansen, Mette

    2007-01-01

    could be involved in secretory processes, which involve cystic fibrosis transmembrane regulator (CFTR) Cl(-) channels or Ca(2+)-activated Cl(-) channels and [Formula: see text] transporters. Reverse transcriptase polymerase chain reaction analysis on rat pancreatic ducts and human duct cell...... pancreatic ducts, plasma membrane of many PANC-1 cells, but only a few CFPAC-1 cells. Taken together, our data indicate that A(2A) receptors open Cl(-) channels in pancreatic ducts cells with functional CFTR. We propose that adenosine can stimulate pancreatic secretion and, thereby, is an active player in...

  17. A modified method for synthesis of [γ-32P] labelled adenosine triphosphate

    Production of [γ-32P]-ATP using three glycolysis enzymatic reaction i.e. glyceraldehyde 3-phosphate dehydrogenase, 3-phosphoglyceric phosphokinase and lactate dehydrogenase has been conducted. dl-glyceraldehyde 3-phosphate, Adenosine Diphosphate and H332PO4 was used as precursors for this reaction. Purification of [γ-32P]-ATP was performed by using DEAE-Sephadex column chromatography. The result suggested that this simple method could be used for producing [γ-32P]-ATP to support the provision of radiolabeled nucleotide for biotechnology research in Indonesia. (author)

  18. Studies on autoantibodies to poly (adenosine diphosphate-ribose) in SLE and other autoimmune diseases.

    Morrow, W J; Isenberg, D. A.; Parry, H F; Shen, L.; Okolie, E E; Farzaneh, F.; Shall, S; Snaith, M L

    1982-01-01

    Sera from 41 patients with systemic lupus erythematosus (SLE), 87 controls with various diseases, and 30 normal subjects were examined for poly (adenosine diphosphate-ribose) and ds DNA binding. Elevated levels of poly (ADP-ribose) binding were found in 73% of the SLE patients compared with 58% who had raised ds DNA binding. In a further study of 160 sera from 27 patients with SLE, levels of antipoly (ADP-ribose) antibodies were shown to correlate with clinical activity better than either ant...

  19. Non-linear quantitative structure-activity relationship for adenine derivatives as competitive inhibitors of adenosine deaminase

    Logistic regression and artificial neural networks have been developed as two non-linear models to establish quantitative structure-activity relationships between structural descriptors and biochemical activity of adenosine based competitive inhibitors, toward adenosine deaminase. The training set included 24 compounds with known k i values. The models were trained to solve two-class problems. Unlike the previous work in which multiple linear regression was used, the highest of positive charge on the molecules was recognized to be in close relation with their inhibition activity, while the electric charge on atom N1 of adenosine was found to be a poor descriptor. Consequently, the previously developed equation was improved and the newly formed one could predict the class of 91.66% of compounds correctly. Also optimized 2-3-1 and 3-4-1 neural networks could increase this rate to 95.83%

  20. Regulation of Maltodextrin Phosphorylase Synthesis in Escherichia coli by Cyclic Adenosine 3′, 5′-Monophosphate and Glucose1

    Chao, Julie; Weathersbee, Carolyn J.

    1974-01-01

    Cyclic adenosine 3′, 5′-monophosphate (AMP) stimulates maltodextrin phosphorylase synthesis in Escherichia coli cells induced with maltose. A maximal effect occurs at 2 to 3 mM cyclic AMP. The action of cyclic AMP is specific, inasmuch as adenosine triphosphate, 3′-AMP, 5′-AMP, adenosine, and dibutyryl cyclic AMP are inactive. Glucose, α-methyl glucoside, 2-deoxyglucose, and pyridoxal 5′-phosphate repress maltodextrin phosphorylase synthesis. This repression is reversed by cyclic AMP. The action of cyclic AMP appears to be at the transcriptional level, since cyclic AMP fails to stimulate phosphorylase production in induced cells in which messenger ribonucleic acid synthesis has been arrested by rifampin or by inducer removal. The two other enzymes involved in the metabolism of maltose, amylomaltase and maltose permease, are also induced in this strain of E. coli and affected by glucose and cyclic AMP in a manner similar to phosphorylase. PMID:4358043

  1. Increased level of soluble adenosine deaminase in bone marrow of visceral leishmaniasis patients: an inverse relation with parasite load.

    Rai, Ambak K; Kumar, Prabin; Saini, Sheetal; Thakur, Chandreshwar P; Seth, Tulika; Mitra, Dipendra K

    2016-09-01

    Adenosine deaminase (ADA) which degrades adenosine to inosine, is known to be pro-inflammatory molecule in many diseases. Adenosine suppresses the functioning of the immune system and thus promotes dissemination of the parasite. In our previous finding, the level of soluble ADA in serum of visceral leishmaniasis (VL) was found to be increased as compared to healthy controls. However, it cannot be fairly interpreted unless their level is demonstrated at the disease site, where the parasite resides. We designed this study to correlate the level of soluble ADA (sADA) with parasitic load at the disease site i.e. bone marrow (BM). We found increased levels of sADA in BM as compared to the unaffected BM. Furthermore, a significant inverse correlation is observed between the parasite load and level of sADA at the disease site. PMID:27447233

  2. Interactions of adenosine, prostaglandins and nitric oxide in hypoxia-induced vasodilatation: in vivo and in vitro studies

    Ray, Clare J; Abbas, Mark R; Coney, Andrew M; Marshall, Janice M

    2002-01-01

    Adenosine, prostaglandins (PG) and nitric oxide (NO) have all been implicated in hypoxia-evoked vasodilatation. We investigated whether their actions are interdependent. In anaesthetised rats, the PG synthesis inhibitors diclofenac or indomethacin reduced muscle vasodilatation evoked by systemic hypoxia or adenosine, but not that evoked by iloprost, a stable analogue of prostacyclin (PGI2), or by an NO donor. After diclofenac, the A1 receptor agonist CCPA evoked no vasodilatation: we previously showed that A1, but not A2A, receptors mediate the hypoxia-induced muscle vasodilatation. Further, in freshly excised rat aorta, adenosine evoked a release of NO, detected with an NO-sensitive electrode, that was abolished by NO synthesis inhibition, or endothelium removal, and reduced by ≈50 % by the A1 antagonist DPCPX, the remainder being attenuated by the A2A antagonist ZM241385. Diclofenac reduced adenosine-evoked NO release by ≈50 % under control conditions, abolished that evoked in the presence of ZM241385, but did not affect that evoked in the presence of DPCPX. Adenosine-evoked NO release was also abolished by the adenyl cyclase inhibitor 2′,5′-dideoxyadenosine, while dose-dependent NO release was evoked by iloprost. Finally, stimulation of A1, but not A2A, receptors caused a release of PGI2 from rat aorta, assessed by radioimmunoassay of its stable metabolite, 6-keto PGF1α, that was abolished by diclofenac. These results suggest that during systemic hypoxia, adenosine acts on endothelial A1 receptors to increase PG synthesis, thereby generating cAMP, which increases the synthesis and release of NO and causes muscle vasodilatation. This pathway may be important in other situations involving these autocoids. PMID:12356892

  3. Synergistic myoprotection of L-arginine and adenosine in a canine model of global myocardial ischaemic reperfusion injury

    DU Lei; DIAN Ke; CHEN Hui-jiao; AN Qi; JIA Meng-xing; YANG Ping-liang; WANG Wei; DENG Shuo-zeng; LIU Jin

    2007-01-01

    Background Endogenous nitric oxide and adenosine increase simultaneously to keep the balance of energy demand and supply when the oxygen supply is insufficient, which suggests that nitric oxide and adenosine might exert a synergistic myoprotection during tissue hypoxia. In this study, we tested this hypothesis utilizing a canine model of prolonged global myocardial ischaemic reperfusion injury.Methods In this double blind, controlled study, the hearts of 24 anaesthetized mongrel dogs were arrested for 2 hours with aortic cross clamping and blood cardioplegia. The treatment groups were those supplemented with 2 mmol/L L-arginine (ARG), supplemented with 1 mmol/L adenosine (ADO), ARG + ADO supplemented with both, and no supplementation (control) (n=6 in each group). Haemodynamics, biochemical indices, adenosine triphosphate (ATP) content and myeloperoxidase activities of myocardium were determined to evaluate myocardial injury. Statistical comparison was performed by two way ANOVA.Results Although the requirements for inotropic supports were higher, the cardiac outputs were lower in control group than in ARG, ADO and the combination groups. Plasma cardiac troponin I levels were higher and the areas of hydropic changes were larger in control group than in ARG and ADO groups. Combination of arginine and adenosine provided further myoprotection with respect to better cardiac performance, lower release of cardiac troponin I, and smaller areas of hydropic changes compared with ARG and ADO groups. ATP content was higher, but myeloperoxidase activities of myocardium were significantly lower in the combination group than in control, ARG and ADO groups (P<0.05).Conclusions Combination of L-arginine and adenosine provides synergistic myoprotection in a canine model of global myocardial ischaemia. Thus, the combination is recommended when the heart is exposed to a prolonged ischaemia during cardiac surgery.

  4. Granulocyte colony-stimulating factor and drugs elevating extracellular adenosine synergize to enhance haematopoietic reconstitution in irradiated mice

    Pospisil, M.; Hofer, M.; Netikova, J.; Hola, J.; Vacek, A. [Academy of Sciences of the Czech Republic, Inst. of Biophysics, Brno (Czech Republic); Znojil, V.; Vacha, J. [Masaryk Univ., Medical Faculty, Brno (Czech Republic)

    1998-03-01

    The activation of adenosine receptors has recently been demonstrated to stimulate haematopoiesis. In the present study, we investigated the ability of drugs elevating extracellular adenosine to influence curative effects of granulocyte colony-stimulating factor (G-CSF) in mice exposed to a sublethal dose of 4 Gy of {sup 60}Co radiation. Elevation of extracellular adenosine in mice was induced by the combined administration of dipyridamole, a drug inhibiting the cellular uptake of adenosine, and adenosine monophosphate (AMP), an adenosine prodrug. The effects of dipyridamole plus AMP, and G-CSF, administered either alone or in combination, were evaluated. The drugs were injected to mice in a 4-d treatment regimen starting on d 3 after irradiation and the haematopoietic response was evaluated on d 7, 10, 14, 18 and 24 after irradiation. While the effects of G-CSF on the late maturation stages of blood cells, appearing shortly after the completion of the treatment, were not influenced by dipyridamole plus AMP, positive effects of the combination therapy occurred in the post-irradiation recovery phase which is dependent on the repopulation of haematopoietic stem cells. This was indicated by the significant elevation of counts of granulocyte-macrophage progenitor cells (GM-CFC) and granulocytic cells in the bone marrow (d 14), of GM-CFC (d 14), granulocytic and erythroid cells (d 14 and 18) in the spleen, and of neutrophils (d 18), monocytes (d 14 and 18) and platelets (d 18) in the peripheral blood. These effects suggest that the repopulation potential of the combination therapy lies in a common multi-lineage cell population. The results of this study implicate the promising possibility to enhance the curative effects of G-CSF under conditions of myelosuppressive state induced by radiation exposure. (au) 43 refs.

  5. The Quintiles Prize Lecture 2004: The identification of the adenosine A2B receptor as a novel therapeutic target in asthma

    Holgate, Stephen T

    2005-01-01

    Adenosine is a powerful bronchoconstrictor of asthmatic, but not normal, airways. In vitro studies on isolated human mast cells and basophils revealed that adenosine and selective analogues augmented inflammatory mediator release from mast cells by stimulating A2 receptors. Pharmacological blockade of mast cell mediator release in vivo also attenuated adenosine-induced bronchoconstriction, as did theophylline, by adenosine A2 receptor antagonism. Further in vitro studies revealed that the asthmatic response to adenosine is likely to be mediated via the A2B subtype which is selectively antagonised by enprofylline. Studies in animal models, especially mice, have shown a close synergistic interaction between adenosine, Th2 and airway remodelling responses. The recent description of A2B receptors on human airway smooth muscle cells that mediate cytokine and chemokine release and induce differentiation of fibroblasts into myofibroblasts strengthens the view that adenosine maybe more than an inflammatory mediator in asthma but also participates in airway wall remodelling in this disease. These data have provided a firm basis for developing adenosine A2B receptor antagonists as a new therapeutic approach to this disease. PMID:15980878

  6. The Quintiles Prize Lecture 2004. The identification of the adenosine A2B receptor as a novel therapeutic target in asthma.

    Holgate, Stephen T

    2005-08-01

    Adenosine is a powerful bronchoconstrictor of asthmatic, but not normal, airways. In vitro studies on isolated human mast cells and basophils revealed that adenosine and selective analogues augmented inflammatory mediator release from mast cells by stimulating A(2) receptors. Pharmacological blockade of mast cell mediator release in vivo also attenuated adenosine-induced bronchoconstriction, as did theophylline, by adenosine A(2) receptor antagonism. Further in vitro studies revealed that the asthmatic response to adenosine is likely to be mediated via the A(2B) subtype which is selectively antagonised by enprofylline. Studies in animal models, especially mice, have shown a close synergistic interaction between adenosine, Th2 and airway remodelling responses. The recent description of A(2B) receptors on human airway smooth muscle cells that mediate cytokine and chemokine release and induce differentiation of fibroblasts into myofibroblasts strengthens the view that adenosine maybe more than an inflammatory mediator in asthma but also participates in airway wall remodelling in this disease. These data have provided a firm basis for developing adenosine A(2B) receptor antagonists as a new therapeutic approach to this disease. PMID:15980878

  7. Measuring the dynamics of cyclic adenosine monophosphate level in living cells induced by low-level laser irradiation using bioluminescence resonance energy transfer

    Huang, Yimei; Zheng, Liqin; Yang, Hongqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen; Zeng, Haishan

    2015-05-01

    Several studies demonstrated that the cyclic adenosine monophosphate (cAMP), an important second messenger, is involved in the mechanism of low-level laser irradiation (LLLI) treatment. However, most of these studies obtained the cAMP level in cell culture extracts or supernatant. In this study, the cAMP level in living cells was measured with bioluminescence resonance energy transfer (BRET). The effect of LLLI on cAMP level in living cells with adenosine receptors blocked was explored to identify the role of adenosine receptors in LLLI. The results showed that LLLI increased the cAMP level. Moreover, the rise of cAMP level was light dose dependent but wavelength independent for 658-, 785-, and 830-nm laser light. The results also exhibited that the adenosine receptors, a class of G protein-coupled receptor (GPCR), modulated the increase of cAMP level induced by LLLI. The cAMP level increased more significantly when the A3 adenosine receptors (A3R) were blocked by A3R antagonist compared with A1 adenosine receptor or A2a adenosine receptor blocked in HEK293T cells after LLLI, which was in good agreement with the adenosine receptors' expressions. All these results suggested that measuring the cAMP level with BRET could be a useful technique to study the role of GPCRs in living cells under LLLI.

  8. Adenosine generation catalyzed by CD39 and CD73 expressed on regulatory T cells mediates immune suppression

    Deaglio, Silvia; Dwyer, Karen M.; GAO, WENDA; Friedman, David; Usheva, Anny; Erat, Anna; Chen, Jiang-Fan; Enjyoji, Keiichii; Linden, Joel; Oukka, Mohamed; Kuchroo, Vijay K.; Strom, Terry B.; Robson, Simon C.

    2007-01-01

    The study of T regulatory cells (T reg cells) has been limited by the lack of specific surface markers and an inability to define mechanisms of suppression. We show that the expression of CD39/ENTPD1 in concert with CD73/ecto-5′-nucleotidase distinguishes CD4+/CD25+/Foxp3+ T reg cells from other T cells. These ectoenzymes generate pericellular adenosine from extracellular nucleotides. The coordinated expression of CD39/CD73 on T reg cells and the adenosine A2A receptor on activated T effector...

  9. CF102 an A3 Adenosine Receptor Agonist Mediates Anti-Tumor and Anti-Inflammatory Effects in the Liver

    Cohen, S.; Stemmer, S M; ZOZULYA, G.; Ochaion, A.; PATOKA, R.; Barer, F.; BAR-YEHUDA, S.; RATH-WOLFSON, L.; Jacobson, K. A.; Fishman, P

    2011-01-01

    The Gi protein-associated A3 adenosine receptor (A3AR) is a member of the adenosine receptor family. Selective agonists at the A3AR, such as CF101 and CF102 were found to induce anti-inflammatory and anti-cancer effects. In this study, we examined the differential effect of CF102 in pathological conditions of the liver. The anti-inflammatory protective effect of CF101 was tested in a model of liver inflammation induced by Concanavalin A (Con. A) and the anti-cancer effect of CF102 was examine...

  10. 32P-incorporation in adenosine phosphates of the rat brain after oral application of vincamine for 2 weeks

    The 32P-incorporation into the adenosine phosphates AMP, ADP and ATP of the rat brain after an oral administration of a daily dose of 20 mg/kg 14.15-dihydro-14β-hydroxy- (3a,16a)-eburnamenine- 14-carbonic acid methylester (vincamine; Vincapront) during two weeks was determined. The concentrations of the three adenosine phosphates did not change. After the administration of vincamine the increase in the 32P-incorporation into AMP and ADP was statistically significant. The results obtained are discussed in regard to an acceleration of the pentose phosphate shunt and an activation of adenylate kinase. (orig.)

  11. Hybrid integrated biological-solid-state system powered with adenosine triphosphate

    Roseman, Jared M.; Lin, Jianxun; Ramakrishnan, Siddharth; Rosenstein, Jacob K.; Shepard, Kenneth L.

    2015-12-01

    There is enormous potential in combining the capabilities of the biological and the solid state to create hybrid engineered systems. While there have been recent efforts to harness power from naturally occurring potentials in living systems in plants and animals to power complementary metal-oxide-semiconductor integrated circuits, here we report the first successful effort to isolate the energetics of an electrogenic ion pump in an engineered in vitro environment to power such an artificial system. An integrated circuit is powered by adenosine triphosphate through the action of Na+/K+ adenosine triphosphatases in an integrated in vitro lipid bilayer membrane. The ion pumps (active in the membrane at numbers exceeding 2 × 106 mm-2) are able to sustain a short-circuit current of 32.6 pA mm-2 and an open-circuit voltage of 78 mV, providing for a maximum power transfer of 1.27 pW mm-2 from a single bilayer. Two series-stacked bilayers provide a voltage sufficient to operate an integrated circuit with a conversion efficiency of chemical to electrical energy of 14.9%.

  12. The efficacy of a novel adenosine agonist (WAG 994) in postoperative dental pain

    Seymour, R A; Hawkesford, J E; Hill, C M; Frame, J; Andrews, C

    1999-01-01

    Aims To determine the comparative efficacy of a new novel adenosine agonist (WAG 994) in postoperative pain after third molar surgery. Methods One hundred and twenty-two patients with postoperative pain after third molar surgery were randomised in a placebo double-blind trial with an active control group. In the early postoperative period patients received either a single dose of WAG 994 1 mg, ibuprofen 400 mg or matched placebos. Pain intensity score was recorded on serial visual analogue scales over a 6 h investigation period. Similarly, pain relief was completed on a 4 point categorical scale at each evaluation point. Patients had access to escape analgesic and if these were taken, the time and dosage were recorded. A sparse sampling technique was used to investigate the relationship between analgesic effects and plasma concentrations of WAG 994. Results All three treatment groups were matched for various demographic variables. For all efficacy measures, WAG 994 was not significantly different from placebo (P > 0.05), whereas ibuprofen 400 mg was significantly superior to placebo (P < 0.001). No significant relationships (P < 0.05) were found between WAG 994 pharmacokinetic variables and efficacy measures. Conclusion WAG 994, an adenosine agonist, did not show efficacy in the management of postoperative pain after third molar surgery. Although this pain responds well to nonsteroidal anti-inflammatory drugs, it appears to be resistant to compounds that interact with purinergic receptors. PMID:10383546

  13. Adenosine and Hypoxia-Inducible Factor Signaling in Intestinal Injury and Recovery

    Eltzschig, Holger K.

    2013-01-01

    The gastrointestinal mucosa has proven to be an interesting tissue in which to investigate disease-related metabolism. In this review, we outline some of the evidence that implicates hypoxia-mediated adenosine signaling as an important signature within both healthy and diseased mucosa. Studies derived from cultured cell systems, animal models, and human patients have revealed that hypoxia is a significant component of the inflammatory microenvironment. These studies have revealed a prominent role for hypoxia-induced factor (HIF) and hypoxia signaling at several steps along the adenine nucleotide metabolism and adenosine receptor signaling pathways. Likewise, studies to date in animal models of intestinal inflammation have demonstrated an almost uniformly beneficial influence of HIF stabilization on disease outcomes. Ongoing studies to define potential similarities with and differences between innate and adaptive immune responses will continue to teach us important lessons about the complexity of the gastrointestinal tract. Such information has provided new insights into disease pathogenesis and, importantly, will provide insights into new therapeutic targets. PMID:21942704

  14. Staurosporine-induced apoptosis in astrocytes is prevented by A1 adenosine receptor activation.

    D'Alimonte, Iolanda; Ballerini, Patrizia; Nargi, Eleonora; Buccella, Silvana; Giuliani, Patricia; Di Iorio, Patrizia; Caciagli, Francesco; Ciccarelli, Renata

    2007-05-11

    Astrocyte apoptosis occurs in acute and chronic pathological processes at the central nervous system and the prevention of astrocyte death may represent an efficacious intervention in protecting neurons against degeneration. Our research shows that rat astrocyte exposure to 100 nM staurosporine for 3h caused apoptotic death accompanied by caspase-3, p38 mitogen-ed protein kinase (MAPK) and glycogen synthase kinase-3beta (GSK3beta) activation. N(6)-chlorocyclopentyladenosine (CCPA, 2.5-75 nM), a selective agonist of A(1) adenosine receptors, added to the cultures 1h prior to staurosporine, induced a dose-dependent anti-apoptotic effect, which was inhibited by the A(1) receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine. CCPA also caused a dose- and time-dependent phosphorylation/activation of Akt, a downstream effector of cell survival promoting phosphatidylinositol 3-kinase (PI3K) pathway, which in turn led to inhibition of staurosporine-induced GSK3beta and p38 MAPK activity. Accordingly, the anti-apoptotic effect of CCPA was abolished by culture pre-treatment with LY294002, a selective PI3K inhibitor, pointing out the prevailing role played by PI3K pathway in the protective effect exerted by A(1) receptor activation. Since an abnormal p38 and GSK3beta activity is implicated in acute (stroke) and chronic (Alzheimer's disease) neurodegenerative diseases, the results of the present study provide a hint to better understand adenosine relevance in these disorders. PMID:17400382

  15. Cross sectional PET study of cerebral adenosine A1 receptors in premanifest and manifest Huntington's disease

    To study cerebral adenosine receptors (AR) in premanifest and manifest stages of Huntington's disease (HD). We quantified the cerebral binding potential (BPND) of the A1AR in carriers of the HD CAG trinucleotide repeat expansion using the radioligand [18 F]CPFPX and PET. Four groups were investigated: (i) premanifest individuals far (preHD-A; n = 7) or (ii) near (preHD-B; n = 6) to the predicted symptom onset, (iii) manifest HD patients (n = 8), and (iv) controls (n = 36). Cerebral A1AR values of preHD-A subjects were generally higher than those of controls (by up to 31 %, p 1AR BPND was observed to the levels of controls in preHD-B and undercutting controls in manifest HD by down to 25 %, p 1AR BPND and years to onset. Before onset of HD, the assumed annual rates of change of A1AR density were -1.2 % in the caudatus, -1.7 % in the thalamus and -3.4 % in the amygdala, while the corresponding volume losses amounted to 0.6 %, 0.1 % and 0.2 %, respectively. Adenosine receptors switch from supra to subnormal levels during phenoconversion of HD. This differential regulation may play a role in the pathophysiology of altered energy metabolism. (orig.)

  16. Adenosine A1 receptors in contrast media-induced renal dysfunction in the normal rat

    Renal vasoconstriction with resultant tissue hypoxia, especially in the renal medulla, has been suggested to play a role in contrast media (CM)-induced nephropathy. In this study we investigated the effects of injection of the non-ionic low-osmolar CM iopromide with and without pretreatment with the selective adenosine A1-receptor antagonist DPCPX. The effects were evaluated on regional renal blood flow, outer medullary oxygen tension (PO2) and urine output in normal anaesthetised rats. A laser-Doppler technique was used for recording haemodynamic changes while oxygen microelectrodes were used for oxygen measurements. The A1-receptor antagonist per se elevated glomerular filtration rate (+44%), cortical blood flow (+15%) and urine output (threefold) while reducing outer medullary PO2 (-24%). Administration of CM reduced outer medullary blood flow (OMBF; -26%) and PO2 (-80%) but did not affect cortical blood flow. Urine output increased 28-fold by CM while arterial blood pressure was reduced. The CM-mediated effect on haemodynamics, PO2, urine output and blood pressure was unaffected by the A1-receptor antagonist. Adenosine A1-receptors are not important mediators of the depression of outer medullary blood flow and PO2 caused by the CM iopromide in the normal rat; however, A1-receptors are tonically active to regulate renal haemodynamics, PO2 and urine production during normal physiological conditions. (orig.)

  17. Formation of guanine ribonucleotidyl-(3'-5')-adenosine in a flavinogenic strain of Eremothecium ashbyii.

    Mitsuda, H; Nishikawa, Y; Nakajima, K

    1976-01-01

    The addition of caffeine caused the accumulation of a new nucleotide compound simultaneously with the rigid inhibition of ribofalvin production in non-growing cells of Eremothecium ashbyii. In the present study we tried to identify the structure of the nucleotide compound using non-growing cells of the mold. 1) It became possible to obtain a large amount of mycelia by masscultivation in a reagent tank. 2) A new nucleotide compound, referred to as compound A in the paper, was extracted with perchloric acid solution and purified by the following subsequent procedures: 1) Dowex 1 x 2 (HCOO-) column, 2) charcoal treatment, 3) DEAE-Sephadex A25 (CI-) column, 4) Dowex 1 x 2 (C1-) column, and 5) DEAE-Sephadex A25 (HCO3-) column. 3) The structure of the new nucleotide compound was proved to be guanine ribonucleotidyl-(3'-5')-adenosine (GpA) from the results of the following analyses: 1) alkaline degradation, 2) UV-spectra, IR-spectra and NMR-spectra, and 3) enzymatic treatments with RNase T2 and phosphodiesterase. 4) The roles of caffeine and guanine ribonucleotidyl-(3'-5')-adenosine in connection with flavinogenesis of this mold were discussed. PMID:182940

  18. Development of gene therapy: potential in severe combined immunodeficiency due to adenosine deaminase deficiency

    Claudia A Montiel-Equihua

    2009-12-01

    Full Text Available Claudia A Montiel-Equihua, Adrian J Thrasher, H Bobby GasparCentre for Immunodeficiency, Molecular Immunology Unit, UCL Institute of Child Health, London, UKAbstract: The history of stem cell gene therapy is strongly linked to the development of gene therapy for severe combined immunodeficiencies (SCID and especially adenosine deaminase (ADA-deficient SCID. Here we discuss the developments achieved in over two decades of clinical and laboratory research that led to the establishment of a protocol for the autologous transplant of retroviral vector-mediated gene-modified hematopoietic stem cells, which has proved to be both successful and, to date, safe. Patients in trials in three different countries have shown long-term immunological and metabolic correction. Nevertheless, improvements to the safety profile of viral vectors are underway and will undoubtedly reinforce the position of stem cell gene therapy as a treatment option for ADA-SCID.Keywords: adenosine deaminase, severe combined immunodeficiency, gene therapy, hematopoietic stem cell, retrovirus, clinical trial

  19. A 24-Year Enzyme Replacement Therapy in an Adenosine-deaminase-Deficient Patient.

    Tartibi, Hana M; Hershfield, Michael S; Bahna, Sami L

    2016-01-01

    Severe combined immunodeficiency (SCID) is a fatal childhood disease unless immune reconstitution is performed early in life, with either hematopoietic stem cell transplantation or gene therapy. One of its subtypes is caused by adenosine deaminase (ADA) enzyme deficiency, which leads to the accumulation of toxic metabolites that impair lymphocyte development and function. With the development of polyethylene glycol-conjugated adenosine deaminase (PEG-ADA) enzyme replacement therapy, many ADA-deficient children with SCID who could not receive a hematopoietic stem cell transplantation or gene therapy survived and had longer and healthier lives. We report a 24-year course of treatment in a patient who was diagnosed with ADA deficiency at 4 months of age. The patient was treated with PEG-ADA, which was the only therapy available for him. The patient's plasma ADA level was regularly monitored and the PEG-ADA dose adjusted accordingly. This treatment has resulted in near-normalization of lymphocyte counts, and his clinical course has been associated with only minor to moderate infections. Thus far, he has had no manifestations of autoimmune or lymphoproliferative disorders. This patient is among the longest to be maintained on PEG-ADA enzyme replacement therapy. PMID:26684479

  20. The pharmacological activation of adenosine A1 and A3 receptors does not modulate the long- or short-term repopulating ability of hematopoietic stem and multipotent progenitor cells in mice

    Hofer, Michal; Pospíšil, Milan; Hoferová, Zuzana; Komůrková, Denisa; Páral, Petr; Savvulidi, Filipp; Šefc, Luděk

    2012-01-01

    This study continues our earlier findings on the hematopoiesis-modulating effects of adenosine A1 and A3 receptor agonists that were performed on committed hematopoietic progenitor and precursor cell populations. In the earlier experiments, N6-cyclopentyladenosine (CPA), an adenosine A1 receptor agonist, was found to inhibit proliferation in the above-mentioned hematopoietic cell systems, whereas N6-(3-iodobenzyl)adenosine-5′-N-methyluronamide (IB-MECA), an adenosine A3 receptor agonist, was ...

  1. Evaluation of coronary artery disease using myocardial thallium-201 imaging with single photon emission computed tomography during adenosine induced coronary vasodilation

    Adenosine-loaded Tl-201 myocardial SPECT was performed in consecutive 55 patients with suspected ischemic heart disease. Among these patients, 22 had cuncurrently exercise Tl-201 myocardial SPECT imaging for comparison. Adenosine was intravenously injected at a dose of 0.14 mg/kg/min continuously for 6 min, and 3 min after the stard of injection Tl-201 was injected via the different vein. Myocardial SPECT images were acquired at 5 min and 3 hr after the completion of intravenous injection of adenosine. Perfusion defect and the presence or absence of redistribution (RD) were visually interpreted from the short- and long-axial tomograms. Relative Tl-201 regional uptake ratios were quantitatively determined. Decreased systolic arterial pressure, increased heart rate, and slightly increased rate-pressure product were observed with adenosine injection. Chest pain (13 patients), head-ache (7), ST depression (17), and A-V block II were also seen; however, these symptoms rapidly disappeared with the withdrawal of adenosine. The findings by adenosine loading were concordent with those by exercise loading (91% for perfusion defect and 86% for presence or absence of RD). According to segments, both loading tests were concordent in 90% for persusion and 89% for RD. Both adenosine- and exercise-loaded imagings correlated well with regional Tl uptake by segements, the lowest value of Tl-201 defect, and extent score of Tl-201 defect. Adenosine-loaded imaging had a sensitivity of 100%, a specificity of 88%, and an accuracy of 97% for detecting parenchymal coronary lesions in evaluable 39 patients. In evaluable 22 patients, the sensitivity, specificity, and accuracy were 100%, 83%, and 95% for adenosine-loaded imaging and 88%, 83%, and 86% for exercise-loaded imaging. Thus, adenosine-loaded Tl-201 myocardial SPECT may be a safety and useful method for diagnosing ischemic heart disease. (N.K.)

  2. Novel iron complexes bearing N6-substituted adenosine derivatives: Synthesis, magnetic, Fe-57 Mossbauer, DFT, and in vitro cytotoxicity studies

    Trávníček, Zdeněk; Mikulík, J.; Čajan, Michal; Zbořil, R.; Popa, Igor

    2008-01-01

    Roč. 16, č. 18 (2008), s. 8719-8728. ISSN 0968-0896 Institutional research plan: CEZ:AV0Z50380511 Keywords : iron complexes * adenosine derivatives * Fe-57 Mossbauer spectroscopy Subject RIV: CE - Biochemistry Impact factor: 3.075, year: 2008

  3. Bronchial responsiveness to adenosine 5 '-monophosphate (AMP) and methacholine differ in their relationship with airway allergy and baseline FEV

    De Meer, G; Heederik, D; Postma, DS

    2002-01-01

    Bronchial hyperresponsiveness (BHR) and inflammation are central hallmarks of asthma. Studies in patients with asthma suggest that BHR to adenosine 5'-monophosphate (AMP) is a better marker of bronchial inflammation than BHR to methacholine. The association between markers of airway inflammation and

  4. Effects of dibutyryl cyclic adenosine monophosphate on hypercapnic depression of diaphragmatic contractility in pentobarbital-anesthetized dogs

    FUJII, YOSHITAKA; Uemura, Aki

    2010-01-01

    Background: Hypercapnia is associated with diaphragm muscle dysfunction that causes a reduction of diaphragmatic force generated for a constant elective myographic activity. No published data are available concerning hypercapnic depression of diaphragmatic contractility during dibutyryl cyclic adenosine monophospate (DBcAMP) administration.

  5. Effects of adenosine A3 receptor agonist on bone marrow granulocytic system in 5-fluorouracil-treated mice

    Hofer, Michal; Pospíšil, Milan; Vacek, Antonín; Holá, Jiřina; Znojil, V.; Weiterová, Lenka; Štreitová, Denisa

    2006-01-01

    Roč. 538, - (2006), s. 163-167. ISSN 0014-2999 R&D Projects: GA ČR(CZ) GA305/06/0015 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z5004920 Keywords : adenosine A3 receptor * granulopoiesis * mouse Subject RIV: BO - Biophysics Impact factor: 2.522, year: 2006

  6. RELATIONSHIP BETWEEN THE ATP (ADENOSINE TRIPHOSPHATE) CONTENT OF SUBSURFACE MATERIAL AND THE RATE OF BIODEGRADATION OF ALKYLBENZENES AND CHLOROBENZENE

    The rate of biotransformation of toluene in unconsolidated subsurface material from sites at Lula, Oklahoma, USA and Conroe, Texas, USA was compared to the ATP (adenosine triphosphate) content of these materials. The rate of toluene degradation decreased with decreasing ATP conte...

  7. Elevation of extracellular adenosine enhances haemopoiesis-stimulating effects of G-CSF in normal and gamma-irradiated mice

    Effects of combined treatment with drugs elevating extracellular adenosine (dipyridamole /DP/, inhibiting the extracellular uptake of adenosine, and adenosine monophosphate /AMP/, an adenosine pro-drug), and G-CSF (granulocyte colony-stimulating factor) on haemopoiesis of normal and gamma-irradiated mice were ascertained. The agents were administered alone or in combination in a 4-day regimen. In normal, unirradiated animals, the haematological endpoints were determined 24 hours after the completion of the treatment. It was shown that the effects of G-CSF, i.e., increases in peripheral blood neutrophils, granulocyte-macrophage progenitor cells (GM-CFC) and morphologically recognizable granulocyte cells in femoral marrow and a decrease in the marrow erythroid cells, can be enhanced by the combination of DP plus AMP administrated 30 minutes before G-CSF. Furthermore, it was found that the stimulatory action of DP plus AMP was expressed particularly at lower doses of G-CSF (1.5, 3, and 4.5 μg/d). In experiments with irradiated mice, when the 4-day therapeutic regimen was applied on days 3 to 6 following irradiation with the dose of 4 Gy, analogical stimulation of granulopoiesis was observed in the recovery phase on days 14 and 18 after irradiation. As example, see Fig. 1 for counts of granulocyte cells in femoral bone marrow. (authors)

  8. Combined pharmacological therapy of the acute radiation disease using a cyclooxygenase-2 inhibitor and an adenosine A(3) receptor agonist

    Hofer, Michal; Pospíšil, Milan; Dušek, L.; Hoferová, Zuzana; Komůrková, Denisa

    2014-01-01

    Roč. 9, č. 6 (2014), s. 642-646. ISSN 1895-104X R&D Projects: GA ČR(CZ) GAP303/11/0128 Institutional support: RVO:68081707 Keywords : Hematopoiesis * Cyclooxygenase inhibition * Adenosine receptor agonist Subject RIV: BO - Biophysics Impact factor: 0.710, year: 2014

  9. A1 not A2A adenosine receptors play a role in cortical epileptic afterdischarges in immature rats

    Mareš, Pavel

    2014-01-01

    Roč. 121, č. 11 (2014), s. 1329-1336. ISSN 0300-9564 R&D Projects: GA MŠk(CZ) LH11015 Institutional support: RVO:67985823 Keywords : adenosine receptors * epileptic afterdischarges * cerebral cortex * ontogeny * rat Subject RIV: FH - Neurology Impact factor: 2.402, year: 2014

  10. DNA-templated silver nanoclusters based label-free fluorescent molecular beacon for the detection of adenosine deaminase.

    Zhang, Kai; Wang, Ke; Xie, Minhao; Zhu, Xue; Xu, Lan; Yang, Runlin; Huang, Biao; Zhu, Xiaoli

    2014-02-15

    A general and reliable fluorescent molecular beacon is proposed in this work utilizing DNA-templated silver nanoclusters (AgNCs). The fluorescent molecular beacon has been employed for sensitive determination of the concentration of adenosine deaminase (ADA) and its inhibition. A well-designed oligonucleotide containing three functional regions (an aptamer region for adenosine assembly, a sequence complementary to the region of the adenosine aptamer, and an inserted six bases cytosine-loop) is adopted as the core element in the strategy. The enzymatic reaction of adenosine catalyzed by ADA plays a key role as well in the regulation of the synthesis of the DNA-templated AgNCs, i.e. the signal indicator. The intensity of the fluorescence signal may thereby determine the concentration of the enzyme and its inhibitor. The detection limit of the ADA can be lowered to 0.05 UL(-1). Also, 100 fM of a known inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine hydrochloride (EHNA) is enough to present distinguishable fluorescence emission. Moreover, since the fluorescent signal indicator is not required to be bound with the oligonucleotide, this fluorescent molecular beacon may integrate the advantages of both the label-free and signal-on strategies. PMID:24035856

  11. Elevation of extracellular adenosine enhances haemopoiesis-stimulating effects of G-CSF in normal and gamma-irradiated mice

    Hofer, M.; Pospisil, M.; Netikiva, J.; Hola, J. [Institute of Biophysics, Academy of Sciences of the Czech Republic (Czech Republic)

    1997-03-01

    Effects of combined treatment with drugs elevating extracellular adenosine (dipyridamole /DP/, inhibiting the extracellular uptake of adenosine, and adenosine monophosphate /AMP/, an adenosine pro-drug), and G-CSF (granulocyte colony-stimulating factor) on haemopoiesis of normal and gamma-irradiated mice were ascertained. The agents were administered alone or in combination in a 4-day regimen. In normal, unirradiated animals, the haematological endpoints were determined 24 hours after the completion of the treatment. It was shown that the effects of G-CSF, i.e., increases in peripheral blood neutrophils, granulocyte-macrophage progenitor cells (GM-CFC) and morphologically recognizable granulocyte cells in femoral marrow and a decrease in the marrow erythroid cells, can be enhanced by the combination of DP plus AMP administrated 30 minutes before G-CSF. Furthermore, it was found that the stimulatory action of DP plus AMP was expressed particularly at lower doses of G-CSF (1.5, 3, and 4.5 {mu}g/d). In experiments with irradiated mice, when the 4-day therapeutic regimen was applied on days 3 to 6 following irradiation with the dose of 4 Gy, analogical stimulation of granulopoiesis was observed in the recovery phase on days 14 and 18 after irradiation. As example, see Fig. 1 for counts of granulocyte cells in femoral bone marrow. (authors)

  12. IB-MECA, an Adenosine A(3) Receptor Agonist, Does Not Influence Survival of Lethally gamma-Irradiated Mice

    Hofer, Michal; Pospíšil, Milan; Dušek, L.; Hoferová, Zuzana; Komůrková, Denisa

    2012-01-01

    Roč. 61, č. 6 (2012), s. 649-654. ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA305/08/0158; GA ČR(CZ) GAP303/11/0128 Institutional support: RVO:68081707 Keywords : Mouse * IB-MECA * Adenosine A(3) receptor agonist Subject RIV: BO - Biophysics Impact factor: 1.531, year: 2012

  13. Comparison of interferon-gamma release assays and adenosine deaminase of pleural fluid for the diagnosis of pleural tuberculosis

    刘菲

    2014-01-01

    Objective To compare the diagnostic performance of interferon gamma releasing assays(T-SPOT.TB)and adenosine deaminase(ADA)in pleural tuberculosis,and therefore to evaluate the value of T-SPOT.TB in a high tuberculosis burden country.Methods From June 2011to November 2012,111 patients with pleural fluid in Beijing Chest Hospital,Capital Medical University were

  14. A3 Adenosine Receptor Allosteric Modulator Induces an Anti-Inflammatory Effect: In Vivo Studies and Molecular Mechanism of Action

    Shira Cohen

    2014-01-01

    Full Text Available The A3 adenosine receptor (A3AR is overexpressed in inflammatory cells and in the peripheral blood mononuclear cells of individuals with inflammatory conditions. Agonists to the A3AR are known to induce specific anti-inflammatory effects upon chronic treatment. LUF6000 is an allosteric compound known to modulate the A3AR and render the endogenous ligand adenosine to bind to the receptor with higher affinity. The advantage of allosteric modulators is their capability to target specifically areas where adenosine levels are increased such as inflammatory and tumor sites, whereas normal body cells and tissues are refractory to the allosteric modulators due to low adenosine levels. LUF6000 administration induced anti-inflammatory effect in 3 experimental animal models of rat adjuvant induced arthritis, monoiodoacetate induced osteoarthritis, and concanavalin A induced liver inflammation in mice. The molecular mechanism of action points to deregulation of signaling proteins including PI3K, IKK, IκB, Jak-2, and STAT-1, resulting in decreased levels of NF-κB, known to mediate inflammatory effects. Moreover, LUF6000 induced a slight stimulatory effect on the number of normal white blood cells and neutrophils. The anti-inflammatory effect of LUF6000, mechanism of action, and the differential effects on inflammatory and normal cells position this allosteric modulator as an attractive and unique drug candidate.

  15. Synthesis and Properties of a New Water-Soluble Prodrug of the Adenosine A2A Receptor Antagonist MSX-2

    Christa E. Müller

    2008-02-01

    Full Text Available The compound L-valine-3-{8-[(E-2-[3-methoxyphenylethenyl]-7-methyl-1-propargylxanthine-3-yl}propyl ester hydrochloride (MSX-4 was synthesized as an aminoacid ester prodrug of the adenosine A2A receptor antagonist MSX-2. It was found to bestable in artificial gastric acid, but readily cleaved by pig liver esterase.

  16. Diagnostic Accuracy of Adenosine Stress Cardiovascular Magnetic Resonance Following Acute ST-segment Elevation Myocardial Infarction Post Primary Angioplasty

    Wong Dennis TL

    2011-10-01

    Full Text Available Abstract Background Adenosine stress cardiovascular magnetic resonance (CMR has been proven an effective tool in detection of reversible ischemia. Limited evidence is available regarding its accuracy in the setting of acute coronary syndromes, particularly in evaluating the significance of non-culprit vessel ischaemia. Adenosine stress CMR and recent advances in semi-quantitative image analysis may prove effective in this area. We sought to determine the diagnostic accuracy of semi-quantitative versus visual assessment of adenosine stress CMR in detecting ischemia in non-culprit territory vessels early after primary percutaneous coronary intervention (PCI for ST-segment elevation myocardial infarction (STEMI. Methods Patients were prospectively enrolled in a CMR imaging protocol with rest and adenosine stress perfusion, viability and cardiac functional assessment 3 days after successful primary-PCI for STEMI. Three short axis slices each divided into 6 segments on first pass adenosine perfusion were visually and semi-quantitatively analysed. Diagnostic accuracy of both methods was compared with non-culprit territory vessels utilising quantitative coronary angiography (QCA with significant stenosis defined as ≥70%. Results Fifty patients (age 59 ± 12 years admitted with STEMI were evaluated. All subjects tolerated the adenosine stress CMR imaging protocol with no significant complications. The cohort consisted of 41% anterior and 59% non anterior infarctions. There were a total of 100 non-culprit territory vessels, identified on QCA. The diagnostic accuracy of semi-quantitative analysis was 96% with sensitivity of 99%, specificity of 67%, positive predictive value (PPV of 97% and negative predictive value (NPV of 86%. Visual analysis had a diagnostic accuracy of 93% with sensitivity of 96%, specificity of 50%, PPV of 97% and NPV of 43%. Conclusion Adenosine stress CMR allows accurate detection of non-culprit territory stenosis in patients

  17. Genetic blockade of adenosine A2A receptors induces cognitive impairments and anatomical changes related to psychotic symptoms in mice.

    Moscoso-Castro, Maria; Gracia-Rubio, Irene; Ciruela, Francisco; Valverde, Olga

    2016-07-01

    Schizophrenia is a chronic severe mental disorder with a presumed neurodevelopmental origin, and no effective treatment. Schizophrenia is a multifactorial disease with genetic, environmental and neurochemical etiology. The main theories on the pathophysiology of this disorder include alterations in dopaminergic and glutamatergic neurotransmission in limbic and cortical areas of the brain. Early hypotheses also suggested that nucleoside adenosine is a putative affected neurotransmitter system, and clinical evidence suggests that adenosine adjuvants improve treatment outcomes, especially in poorly responsive patients. Hence, it is important to elucidate the role of the neuromodulator adenosine in the pathophysiology of schizophrenia. A2A adenosine receptor (A2AR) subtypes are expressed in brain areas controlling motivational responses and cognition, including striatum, and in lower levels in hippocampus and cerebral cortex. The aim of this study was to characterize A2AR knockout (KO) mice with complete and specific inactivation of A2AR, as an animal model for schizophrenia. We performed behavioral, anatomical and neurochemical studies to assess psychotic-like symptoms in adult male and female KO and wild-type (WT) littermates. Our results show impairments in inhibitory responses and sensory gating in A2AR KO animals. Hyperlocomotion induced by d-amphetamine and MK-801 was reduced in KO animals when compared to WT littermates. Moreover, A2AR KO animals show motor disturbances, social and cognitive alterations. Finally, behavioral impairments were associated with enlargement of brain lateral ventricles and decreased BDNF levels in the hippocampus. These data highlight the role of adenosine in the pathophysiology of schizophrenia and provide new possibilities for the therapeutic management of schizophrenia. PMID:27133030

  18. A novel transverse push-pull microprobe: in vitro characterization and in vivo demonstration of the enzymatic production of adenosine in the spinal cord dorsal horn.

    Patterson, S L; Sluka, K A; Arnold, M A

    2001-01-01

    Adenosine produces analgesia in the spinal cord and can be formed extracellularly through enzymatic conversion of adenine nucleotides. A transverse push-pull microprobe was developed and characterized to sample extracellular adenosine concentrations of the dorsal horn of the rat spinal cord. Samples collected via this sampling technique reveal that AMP is converted to adenosine in the dorsal horn. This conversion is decreased by the ecto-5'-nucleotidase inhibitor, alpha,beta-methylene ADP. Related behavioral studies demonstrate that AMP administered directly to the spinal cord can reverse the secondary mechanical hyperalgesia characteristic of the intradermal capsaicin model of inflammatory pain. The specific adenosine A(1) receptor antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT) inhibits the antihyperalgesia produced by AMP. This research introduces a novel microprobe that can be used as an adjunct sampling technique to microdialysis and push-pull cannulas. Furthermore, we conclude that AMP is converted to adenosine in the dorsal horn of the spinal cord by ecto-5'-nucleotidase and subsequently may be one source of adenosine, acting through adenosine A(1) receptors in the dorsal horn of the spinal cord, which produce antihyperalgesia. PMID:11145997

  19. Theophylline and adenosine modulate the inflammatory functions of the human neutrophil by exerting an opposing influence on the stimulus-induced increase in intracellular calcium

    Based on evidence that endogenously-produced adenosine inhibited neutrophil responses, the influence of methylxanthine bronchodilators on neutrophil responses stimulated in vitro by n-formyl-methionyl-leucyl-phenylalanine (fMLP) was examined. At concentrations between 10/sup /minus/5/ M and 10/sup /minus/4/ M, theophylline potentiated lysosomal enzyme release by 30 to 50%, superoxide anion formation by 30 to 60%, and neutrophil aggregation. Theophylline at concentrations >10/sup /minus/4/ M inhibited the same responses by >90%. Adenosine deaminase mimicked, whereas adenosine reversed the theophylline potentiation. A potential role for calcium in the modulation of the neutrophil responses by theophylline and adenosine was explored. Theophylline enhanced by >150% the fMLP-stimulated increase in cytoplasmic calcium concentration ([Ca2+]/sub i/) at time points between 5 and 90 sec as measured by Fura-2. Adenosine deaminase induced a comparable enhancement, whereas 3 /times/ 10/sup /minus/7/ M adenosine and 10/sup /minus/7/ M N-ethylcarboxamideadenosine decreased the [Ca2+]/sub i/ in fMLP-stimulated neutrophils. Extracellular calcium was not required for the opposing influences of theophylline and adenosine and neither compound altered fMLP-stimulated 45Ca uptake at the early time points

  20. Selective Phosphonylation of 5'-Adenosine Monophosphate (5'-AMP) via Pyrophosphite [PPi(III)

    Kaye, Karl; Bryant, David E.; Marriott, Katie E. R.; Ohara, Shohei; Fishwick, Colin W. G.; Kee, Terence P.

    2016-05-01

    We describe here experiments which demonstrate the selective phospho-transfer from a plausibly prebiotic condensed phosphorus (P) salt, pyrophosphite [H2P2O5 2-; PPi(III)], to the phosphate group of 5'-adenosine mono phosphate (5'-AMP). We show further that this P-transfer process is accelerated both by divalent metal ions (M2+) and by organic co-factors such as acetate (AcO-). In this specific case of P-transfer from PPi(III) to 5'-AMP, we show a synergistic enhancement of transfer in the combined presence of M2+ & AcO-. Isotopic labelling studies demonstrate that hydrolysis of the phosphonylated 5'-AMP, [P(III)P(V)-5'-AMP], proceeds via nuceophilic attack of water at the Pi(III) terminus.

  1. Cordyceps pruinosa produces cordycepin and N6-(2-hydroxyethyl-adenosine in culture

    Meng Zebin

    2014-01-01

    Full Text Available Cordyceps species are entomophagous pathogens with medicinal properties, mostly linked to cordycepin and N6- (2-hydroxyethyl-adenosine (HEA. An isolate of Cordyceps pruinosa (GZUCC 8552 was obtained from a fruiting body formed on the cocoon a Limacodidae insect collected in Guizhou Province, China. Morphological and molecular analysis (combined 5.8S ITS, RPB1 and 18S RNA confirmed the species to be Cordyceps pruinosa. Metabolites of the isolate grown in liquid static and solid-state media were established by HPLC-MS. Cordycepin (5.311 mg/g and HEA (0.558 mg/g were produced by this strain. This is the first record of cordycepin from an isolate of Cordyceps pruinosa. As Cordyceps pruinosa is a good source of cordycepin and HEA, it could be used as an alternative to the over-collected Cordyceps sinensis.

  2. Characterizations of a new Cordyceps cicadae isolate and production of adenosine and cordycepin

    Yongjun Wang

    2012-06-01

    Full Text Available Cordyceps is a fastidious pathogenic fungus infecting insects, and recent years have witnessed rapid progress in its medical properties. In this study, a wild isolate, C. cicadae MP12, was characterized through in vitro cultivation and its nuclear small-subunit (SSU ribosomal DNA (rDNA data. In vitro culture of C. cicadae MP12 was established by growing its fruiting bodies in a solid matrix. C. cicadae MP12 was inoculated into Cryptotympana atrata cicada pupae for in vivo culture, where the fungi developed its fruiting body as well. The contents of adenosine and cordycepin in dried fruiting bodies after culture were 1421.45µg/g and 1398.12 µg/g, respectively. Therefore, the established cultures from this study could be used for the production of various medically important metabolic substances.

  3. Influences of dibutyryl cyclic adenosine monophosphate and forskolin on human sperm motility in vitro

    Ji-HongLIU; YangLI; Zheng-GuoCAO; Zhang-QunYE

    2003-01-01

    Aim: To study the influences of dibutyryl cyclic adenosine monophosphate (dbcAMP) and forskolin on human sperm motility in vitro. Methods: Semen samples, aseptically obtained by masturbation and prepared by swim-up technique from 20 fertile men, were incubated with different concenlrations of dbcAMP and forskolin at 37℃. Measurements were carried out after l0 min, 20 min, 30 min and 60 min incubation. Motility parameters were estimated by using an automatic analyzing system. Results: Treatment with dbcAMP or forskolin resulted in a significant increase in sperm motility and progressive motility. The larger the concenlrations of dbcAMP or forskolin,the greater the effect appeared. The straight linear velocity and curvilinear velocity were not affected by both agents.Conclusion: dbcAMP and forskolin increase the motility and progressive motility of human sperm in vitro. ( Asian J Androl 2003 Jun; 5: 113-115)

  4.   Adenosine-diphosphate (ADP) reduces infarct size and improves porcine heart function after myocardial infarction

    Bune, Laurids Touborg; Larsen, Jens Kjærgaard Rolighed; Thaning, Pia; Kristensen, Nethe; Rasmussen, Peter Kristian; Rosenmeier, Jaya Birgitte

    2013-01-01

    Acute myocardial infarction continues to be a major cause of morbidity and mortality. Timely reperfusion can substantially improve outcomes and the administration of cardioprotective substances during reperfusion is therefore highly attractive. Adenosine diphosphate (ADP) and uridine-5-triphoshate...... (UTP) are both released during myocardial ischemia, influencing hemodynamics. Both mediate the release of tissue plasminogen activator (t-PA), which can reduce infarct size (IS). The objective of this study was to investigate whether exogenous ADP and UTP administration during reperfusion could reduce...... myocardial IS and whether this correlated to t-PA release or improvements in hemodynamic responses. Hemodynamic variables and t-PA were measured in 22 pigs before, during, and after 45 min of left anterior coronary artery occlusion. During reperfusion, the pigs were randomized to 240 min of intracoronary...

  5. Expression of human adenosine deaminase in mice reconstituted with retrovirus-transduced hematopoietic stem cells

    Recombinant retroviruses encoding human adenosine deaminase have been used to infect murine hematopoietic stem cells. In bone marrow transplant recipients reconstituted with the genetically modified cells, human ADA was detected in peripheral blood mononuclear cells of the recipients for at least 6 months after transplantation. In animals analyzed in detail 4 months after transplantation, human ADA and proviral sequences were detected in all hematopoietic lineages; in several cases, human ADA activity exceeded the endogenous activity. These studies demonstrate the feasibility of introducing a functional human ADA gene into hematopoietic stem cells and obtaining expression in multiple hematopoietic lineages long after transplantation. This approach should be helpful in designing effective gene therapies for severe combined immunodeficiency syndromes in humans

  6. Adenosine triphosphate concentration in relation to microbial biomass in aquatic systems

    Cunningham, H.W. Jr.

    1977-01-01

    Analyses of adenosine triphosphate (ATP) extracted from a sediment community of an aquatic ecosystem by the sulfuric acid method are complicated by inhibitions from inorganic and organic compounds. Inhibitions by inorganic compounds are reversible while those by organic compounds are irreversible. The primary inhibition by organic compounds results by complexing with acid-soluble fulvic acids which will prevent the detection of as much as 80% of the ATP present in a sample by the luciferin-luciferase reaction. Analytical techniques were developed to partially circumvent such interferences. Biomass interpretations from ATP concentrations in aquatic systems are complicated by the diversity of the microbiota and by the variability in the carbon to ATP ratio caused by environmental conditions. However, when levels of ATP are considered as a physiological condition of a sedimentary community, this data provides a means to interpret community metabolism not available hitherto.

  7. Endogenous activation of adenosine A1 receptors promotes post-ischemic electrocortical burst suppression

    Ilie, A; Ciocan, D; Constantinescu, A O; Zagrean, A-M; Nita, D A; Zagrean, L; Moldovan, M

    2009-01-01

    -vessel occlusion" model under chloral hydrate anesthesia. Quantification of BS recovery was carried out using BS ratio. During GCI full electrocortical suppression was attained (BS ratio reached 100%). During the following reperfusion the BS ratio returned to 0. The time course of the decay was exponential after 1...... and 5-min GCI and bi-exponential after 10-min GCI. The BS recovery was progressively delayed with the duration of ischemia. Administration of the A1R antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, 1.25 mg/kg i.p.) accelerated the post-ischemic BS recovery for all GCI durations. Following the 10......-min GCI the effect of DPCPX was only apparent on the initial fast decay of the BS ratio. These data suggest that endogenous adenosine release promotes BS patterns during reperfusion following transient cerebral ischemia. Furthermore, the endogenous A1R activation may be the primary underlying cause of...

  8. Serum Adenosine deaminase activity and C-reactive protein levels in unstable angina

    Rani Surekha

    2003-01-01

    Full Text Available In unstable angina (USA patients, immunological responses contributing to inflammation play a vital role in plaque rupture and thrombosis causing stroke. In the present study an attempt is made to estimate the levels of adenosine deaminase activity, an immunoenzyme marker and C-reactive protein, a marker of inflammation in USA patients. 45 patients presenting USA and 50 age and sex matched healthy controls were included in the study. Serum ADA activity was measured spectrophotometrically at 630nm and serum C-reactive protein was detected using Avitex CRP kit, which is a rapid latex agglutination test. The Mean ADA levels were 41.15 ± 11.04 in patients and 20.71±5.63 in controls and 66.6% of patients and none of the controls were positive to CRP. The present study observed the importance of ADA as a serum marker in addition to CRP for assessing the immune response in USA patients.

  9. Serum adenosine deaminase activity and its isoenzyme in patients treated for tuberculosis

    Objective: Increased serum adenosine deaminase (ADA) activity, mainly associated with tuberculosis can also occur in a number of other diseases thus negatively affecting the diagnostic utility of ADA measurements in tuberculosis. The aim of the study was to determine whether or not the combined use of the activity of ADA, its isoenzymes and differential cell counts would provide a more efficient means of diagnosing tuberculosis than the use of ADA levels alone. Results: Data suggested significant (p0.75) of ADA/sub 2/ADA was found to be better indicator of tuberculosis. Lymphocyte neutrophil ratio (L/N)> 0.69 gave additional benefit to increase the sensitivity and specificity for the use of ADA as marker in diagnosing tuberculosis. Conclusion: The combined use of activity of ADA, its isoenzymes and total and differential cell counts is a better indicator and gives better understanding to diagnose and evaluate tuberculosis and response to therapy. (author)

  10. Overexpression of adenosine A2A receptors in rats: effects on depression, locomotion and anxiety

    Joana E Coelho

    2014-06-01

    Full Text Available Adenosine A2A receptors (A2AR are a sub-type of receptors enriched in basal ganglia, activated by the neuromodulator adenosine, which interact with dopamine D2 receptors. Although this reciprocal antagonistic interaction is well established in motor function, the outcome in dopamine-related behaviors remains uncertain, in particular in depression and anxiety. We have demonstrated an upsurge of A2AR associated to aging and chronic stress. Furthermore, Alzheimer’s disease patients present A2AR accumulation in cortical areas together with depressive signs. We now tested the impact of overexpressing A2AR in forebrain neurons on dopamine related behavior, namely depression. Adult male rats overexpressing human A2AR under the control of CaMKII promoter [Tg(CaMKII-hA2AR] and aged-matched wild-types (WT of the same strain (Sprague-Dawley were studied. The forced swimming test (FST, sucrose preference test (SPT and the open-field test (OFT were performed to evaluate behavioral despair, anhedonia, locomotion and anxiety. Tg(CaMKII-hA2AR animals spent more time floating and less time swimming in the FST and presented a decreased sucrose preference at 48h in the SPT. They also covered higher distances in the OFT and spent more time in the central zone than the WT. The results indicate that Tg(CaMKII-hA2AR rats exhibit depressive-like behavior, hyperlocomotion and altered exploratory behavior. This A2AR overexpression may explain the depressive signs found in aging, chronic stress and Alzheimer’s disease.

  11. Cerebrospinal fluid adenosine deaminase activity: A complimentary tool in the early diagnosis of tuberculous meningitis

    Taori Girdhar M

    2006-03-01

    Full Text Available Abstract Background Tuberculous meningitis (TBM is the commonest form of neurotuberculosis caused by Mycobacterium tuberculosis bacilli (MTB. The diagnosis of TBM is often difficult. A reliable, cost-effective and rapid diagnostic test, which can be performed in any standard pathology laboratory, could be of help in the diagnosis of TBM. In the present study we measured the adenosine deaminase (ADA activity in cerebrospinal fluid (CSF of TBM and non-TBM patients. Method ADA activity in CSF was determined according to a method based on the Berthlot reaction, which is the formation of a colored indophenol complex from ammonia liberated from adenosine, and quantified spectrophotometrically. Results The CSF ADA activity from TBM patients was compared with CSF ADA from non-TBM infectious meningitis patients, and from patients with non-infectious neurological disorders. The mean CSF ADA activity was found to be significantly higher in CSF of TBM patients, 14.31 ± 3.87 (2.99–26.94, mean ± SD with range, than in the CSF from non-TBM infectious meningitis, 9.25 ± 2.14 (4.99–13.96 and from the non-infectious neurological disorders group, 2.71 ± 1.96 (0.00–7.68, P Conclusion This study demonstrated that ADA activity in the CSF of TBM patients, using a cut-off value 11.39 U/L/min, can be useful for the early differential diagnosis of TBM. This test can be performed in any pathology laboratory where more sophisticated methods are not available.

  12. The dopamine-induced coronary vasoconstrictor response is potentiated by adenosine administration in the dog heart.

    Kollár, A; Kékesi, V; Juhász-Nagy, A

    1989-09-01

    The ineffectiveness of beta-adrenergic blockade in abolishing adenosine-induced coronary vasodilation was utilized to demonstrate that dopamine (DA) is capable of eliciting very strong coronary vasoconstrictor actions in vivo. In 2 separate groups of dogs anesthetized with pentobarbital, responses to DA were assessed either by flowmeter recordings or by computer-aided infrared thermography, which senses coronary blood flow-dependent heat emission from the epicardium. In untreated controls, submaximal DA infusions (16 micrograms.kg-1.min-1 iv) elicited a coronary vasodilator response. The thermographic equivalent of this hemodynamic action was an increased epicardial temperature. Pretreatment with oxprenolol (0.5 mg.kg-1 iv) preserved both basic heart activity and cardiac heat emission at levels which were comparable to the control state, but prevented DA mediated excitation of cardiac and coronary beta-adrenoceptors. In this state, DA infusion constricted the coronary arteries and tended to decrease heart emission. However, both types of effects were moderate, and only the hemodynamic effect was statistically significant. If DA was given after the coronary bed had been dilated submaximally by adenosine (30 micrograms.kg-1.min-1 infused into the left heart), the flow-reducing effect of DA became a dramatic phenomenon, and the DA-induced epicardial cooling was significantly potentiated. The results show that after eliminating conventional beta-effects, DA affects the coronary arteries through vasoconstrictor mechanisms. This finding suggests that the DA-induced constriction is limited in undilated coronary arteries by the metabolic autoregulatory capacity of the vessels. PMID:2614933

  13. Modulation of dopamine-mediated facilitation at the neuromuscular junction of Wistar rats: A role for adenosine A1/A2A receptors and P2 purinoceptors.

    Elnozahi, Neveen A; AlQot, Hadir E; Mohy El-Din, Mahmoud M; Bistawroos, Azza E; Abou Zeit-Har, Mohamed S

    2016-06-21

    This study aims to understand how dopamine and the neuromodulators, adenosine and adenosine triphosphate (ATP) modulate neuromuscular transmission. Adenosine and ATP are well-recognized for their regulatory effects on dopamine in the central nervous system. However, if similar interactions occur at the neuromuscular junction is unknown. We hypothesize that the activation of adenosine A1/A2A and/or P2 purinoceptors may influence the action of dopamine on neuromuscular transmission. Using the rat phrenic nerve hemi-diaphragm, we assessed the influence of dopamine, adenosine and ATP on the height of nerve-evoked muscle twitches. We investigated how the selective blockade of adenosine A1 receptors (2.5nM DPCPX), adenosine A2A receptors (50nM CSC) and P2 purinoceptors (100μM suramin) modified the effects of dopamine. Dopamine alone increased indirect muscle contractions while adenosine and ATP either enhanced or depressed nerve-evoked muscle twitches in a concentration-dependent manner. The facilitatory effects of 256μM dopamine were significantly reduced to 29.62±2.79% or 53.69±5.45% in the presence of DPCPX or CSC, respectively, relative to 70.03±1.57% with dopamine alone. Alternatively, the action of 256μM dopamine was potentiated from 70.03±1.57, in the absence of suramin, to 86.83±4.36%, in the presence of suramin. It can be concluded that the activation of adenosine A1 and A2A receptors and P2 purinoceptors potentially play a central role in the regulation of dopamine effects at the neuromuscular junction. Clinically this study offers new insights for the indirect manipulation of neuromuscular transmission for the treatment of disorders characterized by motor dysfunction. PMID:27060487

  14. The adenosine A2B receptor is involved in anion secretion in human pancreatic duct Capan-1 epithelial cells

    Hayashi, M.; Inagaki, A.; Novak, Ivana;

    2016-01-01

    by CFTRinh-172, a cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel inhibitor. The adenosine A2B receptor agonist, BAY 60-6583, increased Isc and whole-cell Cl− currents through CFTR Cl− channels, whereas the A2A receptor agonist, CGS 21680, had negligible effects. The A2B...... cells. These results demonstrate that luminal adenosine regulates anion secretion by activating CFTR Cl− channels via adenosine A2B receptors on the luminal membranes of Capan-1 cells. The present study endorses that purinergic signaling is important in the regulation of pancreatic secretion....

  15. Direct Growth Graphene on Cu Nanoparticles by Chemical Vapor Deposition as Surface-Enhanced Raman Scattering Substrate for Label-Free Detection of Adenosine

    Xu, Shicai; Man, Baoyuan; Jiang, Shouzhen; Wang, Jihua; Wei, Jie; Xu, Shida; Liu, Hanping

    2015-01-01

    We present a graphene/Cu nanoparticle hybrids (G/CuNPs) system as a surface-enhanced Raman scattering (SERS) substrate for adenosine detection. The Cu nanoparticles wrapped around a monolayer graphene shell were directly synthesized on flat quartz by chemical vapor deposition in a mixture of methane and hydrogen. The G/CuNPs showed an excellent SERS enhancement activity for adenosine. The minimum detected concentration of the adenosine in serum was demonstrated as low as 5 nM, and the calibra...

  16. Extracellular 2′,3′-cAMP-adenosine pathway in proximal tubular, thick ascending limb, and collecting duct epithelial cells

    Jackson, Edwin K.; Gillespie, Delbert G.

    2012-01-01

    In a previous study, we demonstrated that human proximal tubular epithelial cells obtained from a commercial source metabolized extracellular 2′,3′-cAMP to 2′-AMP and 3′-AMP and extracellular 2′-AMP and 3′-AMP to adenosine (the extracellular 2′,3′-cAMP-adenosine pathway; extracellular 2′,3′-cAMP → 2′-AMP + 3′-AMP → adenosine). The purpose of this study was to investigate the metabolism of extracellular 2′,3′-cAMP in proximal tubular vs. thick ascending limb vs. collecting duct epithelial cell...

  17. Comparison of the efficacy of topical minoxidil 5% and adenosine 0.75% solutions on male androgenetic alopecia and measuring the patients' satisfactory rate

    Faghihi, Gita; Iraji, Fariba; Rajaee Harandi, manijeh; Askari, Gholamreza

    2013-01-01

    Objective: According to the hypothesis regarding the stimulating effect of adenosine on increasing fibroblast growth factor-7 in dermal papilla cells and its vasorelaxant effect, we performed this study to compare the effect of topical minoxidil 5% and adenosine 0.75% on male pattern androgenic alopecia. Methods and materials: This prospective-randomized study recruited 110 male patients, who suffered from grade II-V Hamilton androgenic alopecia. Fifty-five patients received minoxidil 5% (gr...

  18. Stimulation of adenosine receptors in the nucleus accumbens reverses the expression of cocaine sensitization and cross-sensitization to dopamine D2 receptors in rats

    Hobson, Benjamin D.; Merritt, Kathryn E.; Bachtell, Ryan K.

    2012-01-01

    Adenosine receptors co-localize with dopamine receptors on medium spiny nucleus accumbens (NAc) neurons where they antagonize dopamine receptor activity. It remains unclear whether adenosine receptor stimulation in the NAc restores cocaine-induced enhancements in dopamine receptor sensitivity. The goal of these studies was to determine whether stimulating A1 or A2A receptors in the NAc reduces the expression of cocaine sensitization. Rats were sensitized with 7 daily treatments of cocaine (15...

  19. Efficacy comparison of combined intracoronary administration of high-dose adenosine and tirofiban versus intracoronary tirofiban during primary percutaneous coronary intervention in patients with acute myocardial infarction

    佟子川

    2013-01-01

    Objective To compare the efficacy of intracoronary administration of combined high-dose adenosine and tirofiban versus intracoronary tirofiban during primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction.Methods Consecutive 258 patients with acute ST-segment elevation myocardial infarction (STEMI) underwent primary PCI,treated with thrombus aspiration and then intracoronary tirofiban,and were randomly divided into adenosine group (n=130) and con-

  20. Disinhibition of hippocampal CA3 neurons induced by suppression of an adenosine A1 receptor-mediated inhibitory tonus: Pre- and postsynaptic components

    Alzheimer, Christian; Sutor, Bernd; Ten Bruggencate, Gerrit

    1993-01-01

    Intracellular recordings were performed on hippocampal CA3 neuronsin vitro to investigate the inhibitory tonus generated by endogenously produced adenosine in this brain region. Bath application of the highly selective adenosine A1 receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine at concentrations up to 100 nM induced both spontaneous and stimulus-evoked epileptiform burst discharges. Once induced, the 1,3-dipropyl-8-cyclopentylxanthine-evoked epileptiform activity was apparently irreve...

  1. Correlation between the levels of N6-(Δ2-isopentenyl)-adenosine and synthesis of DNA in germinating rice seeds

    Levels of N6(Δ2-isopentenyl) adenosine as determined by radioimmunoassay increased up to 18 hr, then decreased till 24 hr and again increased up to 48 hr, during the germination of rice seeds. The synthesis of isopentenyl-adenosine as followed by the incorporation of 14C-adenine and precipitation with the antibodies for the hormone showed no significant change up to 24 hr. This may imply that the hormone was generated from the stored precursors. Synthesis of DNA proceeded in cycles with the peaks of incorporation of 3H-thymidine at 18 and 36 hr suggesting a correlation between the levels of cytokinin and the synthesis of DNA up to 24 hr. Cordycopin inhibited the synthesis of isopentenyladenosine and DNA and the inhibition of the synthesis of DNA was reversed by the presence of the hormone. This indicated the involvement of cytokinin in the synthesis of DNA. (author)

  2. Chronic hypoxia increases arterial blood pressure and reduces adenosine and ATP induced vasodilatation in skeletal muscle in healthy humans

    Calbet, J A L; Boushel, Robert Christopher; Robach, P;

    2014-01-01

    altitude than at sea level (P < 0.05). At altitude, the high doses of adenosine and ATP reduced mean arterial blood pressure by 9-12%, independently of FI O2 . The change in vascular conductance in response to ATP was lower at altitude than at sea level by 24 and 38%, during the low and high ATP doses...... protein expression was determined in muscle biopsies after 4 weeks at 3454 m by Western blot. RESULTS: At altitude, mean arterial blood pressure was 13% higher (91 ± 2 vs. 102 ± 3 mmHg, P < 0.05) than at sea level and was unaltered by hyperoxic breathing. Baseline leg vascular conductance was 25% lower at...... blood pressure and reduces the vasodilatory responses to adenosine and ATP....

  3. Silver nanoparticles embedded in amine-functionalized silicate sol-gel network assembly for sensing cysteine, adenosine and NADH

    Maduraiveeran, Govindhan; Ramaraj, Ramasamy, E-mail: ramarajr@yahoo.com [Madurai Kamaraj University, Centre for Photoelectrochemistry, School of Chemistry (India)

    2011-09-15

    Silver nanoparticles embedded in amine-functionalized silicate sol-gel network were synthesized and used for sensing biomolecules such as cysteine, adenosine, and {beta}-nicotinamide adenine dinucleotide (NADH). The sensing of these biomolecules by the assembly of silver nanoparticles was triggered by the optical response of the surface plasmon resonance (SPR) of the silver nanoparticles. The optical sensor exhibited the lowest detection limit (LOD) of 5, 20, and 5 {mu}M for cysteine, adenosine, and NADH, respectively. The sensing of biomolecules in the micromolar range by using the amine-functionalized silicate sol-gel embedded silver nanoparticles was studied in the presence of interference molecules like uridine, glycine, guanine, and guanosine. Thus, the present approach might open up a new avenue for the development of silver nanoparticles-based optical sensor devices for biomolecules.

  4. Crystallization and preliminary X-ray crystallographic analysis of the tRNA-specific adenosine deaminase from Streptococcus pyogenes

    The tRNA-specific adenosine deaminase from the pathogenic bacteria S. pyogenes has been overexpressed and crystallized. The tRNA-specific adenosine deaminase from the pathogenic bacteria Streptococcus pyogenes (spTAD) has been overexpressed in Escherichia coli and crystallized in the presence of Zn2+ ion at 295 K using ammonium sulfate as a precipitant. Flash-cooled crystals of spTAD diffracted to 2.0 Å using 30%(v/v) glycerol as a cryoprotectant. X-ray diffraction data have been collected to 2.0 Å using synchrotron radiation. The crystal belongs to the tetragonal space group P42212, with unit-cell parameters a = b = 81.042, c = 81.270 Å. The asymmetric unit contains one subunit of spTAD, with a corresponding crystal volume per protein weight (VM) of 3.3 Å3 Da−1 and a solvent content of 62.7%

  5. Identification of Electronic and Structural Descriptors of Adenosine Analogues Related to Inhibition of Leishmanial Glyceraldehyde-3-Phosphate Dehydrogenase

    Norka B. H. Lozano

    2013-04-01

    Full Text Available Quantitative structure–activity relationship (QSAR studies were performed in order to identify molecular features responsible for the antileishmanial activity of 61 adenosine analogues acting as inhibitors of the enzyme glyceraldehyde 3-phosphate dehydrogenase of Leishmania mexicana (LmGAPDH. Density functional theory (DFT was employed to calculate quantum-chemical descriptors, while several structural descriptors were generated with Dragon 5.4. Variable selection was undertaken with the ordered predictor selection (OPS algorithm, which provided a set with the most relevant descriptors to perform PLS, PCR and MLR regressions. Reliable and predictive models were obtained, as attested by their high correlation coefficients, as well as the agreement between predicted and experimental values for an external test set. Additional validation procedures were carried out, demonstrating that robust models were developed, providing helpful tools for the optimization of the antileishmanial activity of adenosine compounds.

  6. Mapping adenosine A1 receptors in the cat brain by positron emission tomography with [11C]MPDX

    We evaluated the potential of [11C]MPDX as a radioligand for mapping adenosine A1 receptors in comparison with previously proposed [11C]KF15372 in cat brain by PET. Two tracers showed the same brain distribution. Brain uptake of [11C]MPDX (Ki=4.2 nM) was much higher and washed out faster than that of [11C]KF15372 (Ki=3.0 nM), and was blocked by carrier-loading or displaced with an A1 antagonist. The regional A1 receptor distribution evaluated with kinetic analysis is consistent with that previously measured in vitro. [11C]MPDX PET has a potential for mapping adenosine A1 receptors in brain

  7. Preclinical studies on [{sup 11}C]MPDX for mapping adenosine A{sub 1} receptors by positron emission tomography

    Ishiwata, Kiichi; Kimura, Yuichi; Oda, Keiichi; Kawamura, Kazunori; Ishii, Kenji; Senda, Michio [Tokyo Metropolitan Inst. of Gerontology (Japan). Positron Medical Center; Nariai, Tadashi; Wakabayashi, Shinichi [Tokyo Medical and Dental Univ. (Japan). School of Medicine; Shimada, Junichi [Kyowa Hakko Kogyo Co. Ltd., Tokyo (Japan). Pharmaceutical Research Inst.

    2002-09-01

    In previous in vivo studies with mice, rats and cats, we have demonstrated that [{sup 11}C]MPDX ([1-methyl-{sup 11}C]8-dicyclopropylmethyl-1-methyl-3-propylxanthine) is a potential radioligand for mapping adenosine A{sub 1} receptors of the brain by positron emission tomography (PET). In the present study, we performed a preclinical study. The radiation absorbed-dose by [{sup 11}C]MPDX in humans estimated from the tissue distribution in mice was low enough for clinical use, and the acute toxicity and mutagenicity of MPDX were not found. The monkey brain was clearly visualized by PET with [{sup 11}C]MPDX. We have concluded that [{sup 11}C]MPDX is suitable for mapping adenosine A{sub 1} receptors in the human brain by PET. (author)

  8. Hide and seek: a comparative autoradiographic in vitro investigation of the adenosine A3 receptor

    Since the adenosine A3 receptor (A3R) is considered to be of high clinical importance in the diagnosis and treatment of ischaemic conditions (heart and brain), glaucoma, asthma, arthritis, cancer and inflammation, a suitable and selective A3R PET tracer such as [18F]FE rate at SUPPY would be of high clinical value for clinicians as well as patients. A3R was discovered in the late 1990s, but there is still little known regarding its distribution in the CNS and periphery. Hence, in autoradiographic experiments the distribution of A3R in human brain and rat tissues was investigated and the specific binding of the A3R antagonist FE rate at SUPPY and MRS1523 compared. Immunohistochemical staining (IHC) experiments were also performed to validate the autoradiographic findings. For autoradiographic competition experiments human post-mortem brain and rat tissues were incubated with [125I]AB-MECA and highly selective compounds to block the other adenosine receptor subtypes. Additionally, IHC was performed with an A3 antibody. Specific A3R binding of MRS1523 and FE rate at SUPPY was found in all rat peripheral tissues examined with the highest amounts in the spleen (44.0 % and 46.4 %), lung (44.5 % and 45.0 %), heart (39.9 % and 42.9 %) and testes (27.4 % and 29.5 %, respectively). Low amounts of A3R were found in rat brain tissues (5.9 % and 5.6 %, respectively) and human brain tissues (thalamus 8.0 % and 9.1 %, putamen 7.8 % and 8.2 %, cerebellum 6.0 % and 7.8 %, hippocampus 5.7 % and 5.6 %, caudate nucleus 4.9 % and 6.4 %, cortex 4.9 % and 6.3 %, respectively). The outcome of the A3 antibody staining experiments complemented the results of the autoradiographic experiments. The presence of A3R protein was verified in central and peripheral tissues by autoradiography and IHC. The specificity and selectivity of FE rate at SUPPY was confirmed by direct comparison with MRS1523, providing further evidence that [18F]FE rate at SUPPY may be a suitable A3 PET tracer for use in

  9. Striatal pre- and postsynaptic profile of adenosine A(2A receptor antagonists.

    Marco Orru

    Full Text Available Striatal adenosine A(2A receptors (A(2ARs are highly expressed in medium spiny neurons (MSNs of the indirect efferent pathway, where they heteromerize with dopamine D(2 receptors (D(2Rs. A(2ARs are also localized presynaptically in cortico-striatal glutamatergic terminals contacting MSNs of the direct efferent pathway, where they heteromerize with adenosine A(1 receptors (A(1Rs. It has been hypothesized that postsynaptic A(2AR antagonists should be useful in Parkinson's disease, while presynaptic A(2AR antagonists could be beneficial in dyskinetic disorders, such as Huntington's disease, obsessive-compulsive disorders and drug addiction. The aim or this work was to determine whether selective A(2AR antagonists may be subdivided according to a preferential pre- versus postsynaptic mechanism of action. The potency at blocking the motor output and striatal glutamate release induced by cortical electrical stimulation and the potency at inducing locomotor activation were used as in vivo measures of pre- and postsynaptic activities, respectively. SCH-442416 and KW-6002 showed a significant preferential pre- and postsynaptic profile, respectively, while the other tested compounds (MSX-2, SCH-420814, ZM-241385 and SCH-58261 showed no clear preference. Radioligand-binding experiments were performed in cells expressing A(2AR-D(2R and A(1R-A(2AR heteromers to determine possible differences in the affinity of these compounds for different A(2AR heteromers. Heteromerization played a key role in the presynaptic profile of SCH-442416, since it bound with much less affinity to A(2AR when co-expressed with D(2R than with A(1R. KW-6002 showed the best relative affinity for A(2AR co-expressed with D(2R than co-expressed with A(1R, which can at least partially explain the postsynaptic profile of this compound. Also, the in vitro pharmacological profile of MSX-2, SCH-420814, ZM-241385 and SCH-58261 was is in accordance with their mixed pre- and postsynaptic profile

  10. Hide and seek: a comparative autoradiographic in vitro investigation of the adenosine A3 receptor

    Haeusler, D.; Fuchshuber, F.; Girschele, F.; Hacker, M.; Wadsak, W.; Mitterhauser, Markus [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Grassinger, L. [University of Applied Sciences Wiener Neustadt, Department of Biomedical Analytics, Wiener Neustadt (Austria); Hoerleinsberger, W.J. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); University of Vienna, Cognitive Science Research Platform, Vienna (Austria); Hoeftberger, R.; Leisser, I. [Medical University of Vienna, Institute of Neurology, Vienna (Austria); Shanab, K.; Spreitzer, H. [University of Vienna, Department of Drug and Natural Product Synthesis, Vienna (Austria); Gerdenitsch, W. [Medical University of Vienna, Institute of Biomedicinal Research, Vienna (Austria)

    2015-05-01

    Since the adenosine A3 receptor (A3R) is considered to be of high clinical importance in the diagnosis and treatment of ischaemic conditions (heart and brain), glaucoma, asthma, arthritis, cancer and inflammation, a suitable and selective A3R PET tracer such as [{sup 18}F]FE rate at SUPPY would be of high clinical value for clinicians as well as patients. A3R was discovered in the late 1990s, but there is still little known regarding its distribution in the CNS and periphery. Hence, in autoradiographic experiments the distribution of A3R in human brain and rat tissues was investigated and the specific binding of the A3R antagonist FE rate at SUPPY and MRS1523 compared. Immunohistochemical staining (IHC) experiments were also performed to validate the autoradiographic findings. For autoradiographic competition experiments human post-mortem brain and rat tissues were incubated with [{sup 125}I]AB-MECA and highly selective compounds to block the other adenosine receptor subtypes. Additionally, IHC was performed with an A3 antibody. Specific A3R binding of MRS1523 and FE rate at SUPPY was found in all rat peripheral tissues examined with the highest amounts in the spleen (44.0 % and 46.4 %), lung (44.5 % and 45.0 %), heart (39.9 % and 42.9 %) and testes (27.4 % and 29.5 %, respectively). Low amounts of A3R were found in rat brain tissues (5.9 % and 5.6 %, respectively) and human brain tissues (thalamus 8.0 % and 9.1 %, putamen 7.8 % and 8.2 %, cerebellum 6.0 % and 7.8 %, hippocampus 5.7 % and 5.6 %, caudate nucleus 4.9 % and 6.4 %, cortex 4.9 % and 6.3 %, respectively). The outcome of the A3 antibody staining experiments complemented the results of the autoradiographic experiments. The presence of A3R protein was verified in central and peripheral tissues by autoradiography and IHC. The specificity and selectivity of FE rate at SUPPY was confirmed by direct comparison with MRS1523, providing further evidence that [{sup 18}F]FE rate at SUPPY may be a suitable A3 PET

  11. Direct Growth Graphene on Cu Nanoparticles by Chemical Vapor Deposition as Surface-Enhanced Raman Scattering Substrate for Label-Free Detection of Adenosine

    Xu, Shicai; Jiang, Shouzhen; Wang, Jihua; Wei, Jie; Xu, Shida; Liu, Hanping

    2015-01-01

    We present a graphene/Cu nanoparticle hybrids (G/CuNPs) system as a surface-enhanced Raman scattering (SERS) substrate for adenosine detection. The Cu nanoparticles wrapped around a monolayer graphene shell were directly synthesized on flat quartz by chemical vapor deposition in a mixture of methane and hydrogen. The G/CuNPs showed an excellent SERS enhancement activity for adenosine. The minimum detected concentration of the adenosine in serum was demonstrated as low as 5 nM, and the calibration curve showed a good linear response from 5 to 500 nM. The capability of SERS detection of adenosine in real normal human urine samples based on G/CuNPs was also investigated and the characteristic peaks of adenosine were still recognizable. The reproducible and the ultrasensitive enhanced Raman signals could be due to the presence of an ultrathin graphene layer. The graphene shell was able to enrich and fix the adenosine molecules, which could also efficiently maintain chemical and optical stability of G/CuNPs. Based...

  12. Effects of Adding Adenosine Triphosphate to Semen Diluter on Quality of Spermatozoa of Fat-Tailed Sheep

    E Pramono; TR Tagama

    2008-01-01

    The research aimed to investigate the effects of adding different levels of Adenosine Triphosphate (ATP) to semen diluter on quality of sperms of fat-tailed sheep. Treatments consisted of 5, 10 and 15 mg of ATP addition into semen diluter (Egg Yolk Sodium Citric). Results showed that treatments have no significant effects on spermatozoa motility, significant effects on spermatozoa viability, and high significant effects on spermatozoa mortality. On average, sperm motility for control was 79....

  13. Baclofen and adenosine inhibition of synaptic transmission at CA3-CA1 synapses display differential sensitivity to K+ channel blockade.

    Skov, Jane; Andreasen, Mogens; Hablitz, John J; Nedergaard, Steen

    2011-05-01

    The metabotropic GABA(B) and adenosine A(1) receptors mediate presynaptic inhibition through regulation of voltage-dependent Ca(2+) channels, whereas K(+) channel regulation is believed to have no role at the CA3-CA1 synapse. We show here that the inhibitory effect of baclofen (20 μM) and adenosine (300 μM) on field EPSPs are differentially sensitive to Cs(+) (3.5 mM) and Ba(2+) (200 μM), but not 4-aminopyridine (100 μM). Barium had no effect on paired-pulse facilitation (PPF) in itself, but gave significant reduction (14 ± 5%) when applied in the presence of baclofen, but not adenosine, suggesting that the effect is presynaptic and selective on the GABA(B) receptor-mediated response. The effect of Ba(2+) on PPF was not mimicked by tertiapin (30 nM), indicating that the underlying mechanism does not involve GIRK channels. Barium did not affect PPF in slices from young rats (P7-P8), suggesting developmental regulation. The above effects of Ba(2+) on adult tissue were reproduced when measuring evoked whole-cell EPSCs from CA1 pyramidal neurons: PPF was reduced by 22 ± 3% in the presence of baclofen and unaltered in adenosine. In contrast, Ba(2+) caused no significant change in frequency or amplitude of miniature EPSCs. The Ba(2+)-induced reduction of PPF was antagonized by LY341495, suggesting metabotropic glutamate receptor involvement. We propose that these novel effects of Ba(2+) and Cs(+) are exerted through blockade of inwardly rectifying K(+) channels in glial cells, which are functionally interacting with the GABA(B) receptor-dependent glutamate release that generates heterosynaptic depression. PMID:21274618

  14. Assimilatory sulfate reduction in Escherichia coli: identification of the alternate cofactor for adenosine 3'-phosphate 5'-phosphosulfate reductase as glutaredoxin.

    Tsang, M L

    1981-01-01

    The alternate cofactor (7004 cofactor) for Escherichia coli adenosine 3'-phosphate 5'-phosphosulfate (PAPS) reductase originally discovered in an E. coli mutant (tsnC 7004) lacking thioredoxin activity has now been purified and characterized. The tryptic peptide map of the 7004 cofactor is totally different from that of thioredoxin, indicating that the two proteins are unrelated in their primary structure. The 7004 cofactor has an amino acid composition different from that of thioredoxin but ...

  15. Diastolic Dysfunction Induced by a High-Fat Diet Is Associated with Mitochondrial Abnormality and Adenosine Triphosphate Levels in Rats

    Kang, Ki-Woon; Kim, Ok-Soon; Chin, Jung Yeon; Kim, Won Ho; Park, Sang Hyun; Choi, Yu Jeong; Shin, Jong Ho; Jung, Kyung Tae; Lim, Do-Seon; Lee, Seong-Kyu

    2015-01-01

    Background Obesity is well-known as a risk factor for heart failure, including diastolic dysfunction. However, this mechanism in high-fat diet (HFD)-induced obese rats remain controversial. The purpose of this study was to investigate whether cardiac dysfunction develops when rats are fed with a HFD for 10 weeks; additionally, we sought to investigate the association between mitochondrial abnormalities, adenosine triphosphate (ATP) levels and cardiac dysfunction. Methods We examined myocardia...

  16. Fetal tachyarrhythmia with 1:1 atrioventricular conduction. Adenosine infusion in the umbilical vein as a diagnostic test

    Tiago L. L. Leiria

    2000-07-01

    Full Text Available This is the report of a case of fetal tachyarrhythmia with 1:1 atrioventricular conduction detected by pre-natal echocardiography in a fetus at 25-weeks gestation. Adenosine infusion via cordocentesis was performed as a diagnostic test to differentiate between atrioventricular nodal reentrant supraventricular tachyarrhythmia and atrial flutter. After infusion, transient 2:1 atrioventricular dissociation was obtained and the diagnosis of atrial flutter was made. Transplacental therapy with digoxin and amiodarone was then successfully used.

  17. Effects of stable adenosine receptor agonists on bone marrow haematopoietic cells as inferred from the cytotoxic action of 5-fluorouracil

    Pospíšil, Milan; Hofer, Michal; Vacek, Antonín; Znojil, V.; Pipalová, I.

    2004-01-01

    Roč. 53, č. 3 (2004), s. 549-556. ISSN 0862-8408 R&D Projects: GA ČR GA305/02/0423; GA AV ČR IBS5004009; GA AV ČR KSK5011112 Institutional research plan: CEZ:AV0Z5004920 Keywords : adenosine receptor agonists * hematopoiesis * 5-fluorouracil Subject RIV: BO - Biophysics Impact factor: 1.140, year: 2004

  18. Retrovirus-mediated gene transfer of human adenosine deaminase: expression of functional enzyme in murine hematopoietic stem cells in vivo.

    Lim, B; Williams, D A; Orkin, S H

    1987-01-01

    Simplified Moloney murine leukemia virus-based recombinant retrovirus vectors have been constructed which transduce human adenosine deaminase (ADA) cDNA. ADA transcription is under the control of the constitutive promoter for the human X chromosome phosphoglycerate kinase (pgk) gene. In these simplified vectors, dominant selectable markers are not included and selection is dependent on overproduction of functional ADA enzyme. Primary murine hematopoietic cells were infected with helper-free r...

  19. The Effects of Nucleus Accumbens μ-opioid and Adenosine 2A Receptor Stimulation and Blockade on Instrumental Learning

    Clissold, Kara A.; Pratt, Wayne E.

    2014-01-01

    Prior research has shown that glutamate and dopamine receptors in the nucleus accumbens (NAcc) core are critical for the learning of an instrumental response for food reinforcement. It has also been demonstrated that μ-opioid and adenosine A2A receptors within the NAcc impact feeding and motivational processes. In these experiments, we examined the potential roles of NAcc μ-opioid and A2A receptors on instrumental learning and performance. Sprague-Dawley rats were food restricted and trained ...

  20. Adenosine A2A receptors in ventral striatum, hypothalamus and nociceptive circuitry. Implications for drug addiction, sleep and pain

    Ferré, S.; Diamond, I.; Goldberg, S. R.; Yao, L.; Hourani, S.M.O.; Huang, Z L; Urade, Y; Kitchen, I.

    2007-01-01

    Adenosine A2A receptors localized in the dorsal striatum are considered as a new target for the development of antiparkinsonian drugs. Co-administration of A2A receptor antagonists has shown a significant improvement of the effects of L-DOPA. The present review emphasizes the possible application of A2A receptor antagonists in pathological conditions other than parkinsonism, including drug addiction, sleep disorders and pain. In addition to the dorsal striatum, the ventral striatum (nucleus a...

  1. Influence of metabotropic glutamate receptor agonists on the inhibitory effects of adenosine A1 receptor activation in the rat hippocampus

    de Mendonça, Alexandre; Ribeiro, J. A.

    1997-01-01

    Glutamate and other amino acids are the main excitatory neurotransmitters in many brain regions, including the hippocampus, by activating ion channel-coupled glutamate receptors, as well as metabotropic receptors linked to G proteins and second messenger systems. Several conditions which promote the release of glutamate, like frequency stimulation and hypoxia, also lead to an increase in the extracellular levels of the important neuromodulator, adenosine. We studied whether the activation of ...

  2. Increased orbitofrontal brain activation after administration of a selective adenosine A2A antagonist in cocaine dependent subjects

    F. Gerard eMoeller

    2012-05-01

    Full Text Available Background: Positron Emission Tomography imaging studies provide evidence of reduced dopamine function in cocaine dependent subjects in the striatum, which is correlated with prefrontal cortical glucose metabolism, particularly in the orbitofrontal cortex. However, whether enhancement of dopamine in the striatum in cocaine dependent subjects would be associated with changes in prefrontal cortical brain activation is unknown. One novel class of medications that enhance dopamine function via heteromer formation with dopamine receptors in the striatum is the selective adenosine A2A receptor antagonists. This study sought to determine the effects administration of the selective adenosine A2A receptor antagonist SYN115 on brain function in cocaine dependent subjects. Methodology/Principle Findings: Twelve cocaine dependent subjects underwent two fMRI scans (one after a dose of placebo and one after a dose of 100 mg of SYN115 while performing a working memory task with 3 levels of difficulty (3, 5, and 7 digits. fMRI results showed that for 7-digit working memory activation there was significantly greater activation from SYN115 compared to placebo in portions of left (L lateral orbitofrontal cortex, L insula, and L superior and middle temporal pole. Conclusion/Significance: These findings are consistent with enhanced dopamine function in the striatum in cocaine dependent subjects via blockade of adenosine A2A receptors producing increased brain activation in the orbitofrontal cortex and other cortical regions. This suggests that at least some of the changes in brain activation in prefrontal cortical regions in cocaine dependent subjects may be related to altered striatal dopamine function, and that enhancement of dopamine function via adenosine A2A receptor blockade could be explored further for amelioration of neurobehavioral deficits associated with chronic cocaine use.

  3. Activation of NTS A1 adenosine receptors inhibits regional sympathetic responses evoked by activation of cardiopulmonary chemoreflex

    Ichinose, Tomoko K.; Minic, Zeljka; Li, Cailian; O'Leary, Donal S.; Scislo, Tadeusz J.

    2012-01-01

    Previously we have shown that adenosine operating via the A1 receptor subtype may inhibit glutamatergic transmission in the baroreflex arc within the nucleus of the solitary tract (NTS) and differentially increase renal (RSNA), preganglionic adrenal (pre-ASNA), and lumbar (LSNA) sympathetic nerve activity (ASNA>RSNA≥LSNA). Since the cardiopulmonary chemoreflex and the arterial baroreflex are mediated via similar medullary pathways, and glutamate is a primary transmitter in both pathways, it i...

  4. Combined Contribution of Endothelial Relaxing Autacoides in the Rat Femoral Artery Response to CPCA: An Adenosine A2 Receptor Agonist

    Miroslav Radenković; Marko Stojanović; Radmila Janković; Mirko Topalović; Milica Stojiljković

    2012-01-01

    We examined the contribution of endothelial relaxing factors and potassium channels in actions of CPCA, potent adenosine A2 receptor agonist, on isolated intact male rat femoral artery (FA). CPCA produced concentration-dependent relaxation of FA, which was notably, but not completely, reduced after endothelial denudation. DPCPX, A1 receptor antagonist, had no significant effect, while SCH 58261 (A2A receptor antagonist) notably reduced CPCA-evoked effect. Pharmacological inhibition of nitric ...

  5. Purine metabolic enzymes in lymphocytes. III. Effects of immunosuppressants on adenosine deaminase and purine nucleoside phosphorylase activities

    Kurashige, Satonori; Akuzawa, Yuki; Yoshida, Toshiharu; Kodama, Kazue

    1983-01-01

    Mice were treated with a single injection of 6-mercaptopurine riboside (6MP-R), predonine or cyclophosphamide (CY), and the effects of these immunosuppressants on blastogenic responses to phytohemagglutinin P (PHA-P) or bacterial lipopoly saccharide (LPS) and on adenosine deaminase (ADA) or purine nucleoside phosphorylase (PNP) activities were studied with spleen lymphocytes. The retardation of blastogenic responses to both PHA-P and LPS were associated with the retardation of both intracellu...

  6. Detection of adenosine triphosphate through polymerization-induced aggregation of actin-conjugated gold/silver nanorods

    Liao, Yu-Ju; Shiang, Yen-Chun; Chen, Li-Yi; Hsu, Chia-Lun; Huang, Chih-Ching; Chang, Huan-Tsung

    2013-11-01

    We have developed a simple and selective nanosensor for the optical detection of adenosine triphosphate (ATP) using globular actin-conjugated gold/silver nanorods (G-actin-Au/Ag NRs). By simply mixing G-actin and Au/Ag NRs (length ˜56 nm and diameter ˜12 nm), G-actin-Au/Ag NRs were prepared which were stable in physiological solutions (25 mM Tris-HCl, 150 mM NaCl, 5.0 mM KCl, 3.0 mM MgCl2 and 1.0 mM CaCl2; pH 7.4). Introduction of ATP into the G-actin-Au/Ag NR solutions in the presence of excess G-actin induced the formation of filamentous actin-conjugated Au/Ag NR aggregates through ATP-induced polymerization of G-actin. When compared to G-actin-modified spherical Au nanoparticles having a size of 13 nm or 56 nm, G-actin-Au/Ag NRs provided better sensitivity for ATP, mainly because the longitudinal surface plasmon absorbance of the Au/Ag NR has a more sensitive response to aggregation. This G-actin-Au/Ag NR probe provided high sensitivity (limit of detection 25 nM) for ATP with remarkable selectivity (>10-fold) over other adenine nucleotides (adenosine, adenosine monophosphate and adenosine diphosphate) and nucleoside triphosphates (guanosine triphosphate, cytidine triphosphate and uridine triphosphate). It also allowed the determination of ATP concentrations in plasma samples without conducting tedious sample pretreatments; the only necessary step was simple dilution. Our experimental results are in good agreement with those obtained from a commercial luciferin-luciferase bioluminescence assay. Our simple, sensitive and selective approach appears to have a practical potential for the clinical diagnosis of diseases (e.g. cystic fibrosis) associated with changes in ATP concentrations.

  7. Drugs elevating extracellular adenosine administered in vivo induce serum colony-stimulating activity and interleukin-6 in mice

    Weiterová, Lenka; Hofer, Michal; Pospíšil, Milan; Znojil, V.; Štreitová, Denisa

    2007-01-01

    Roč. 56, č. 4 (2007), s. 463-473. ISSN 0862-8408 R&D Projects: GA ČR(CZ) GP305/03/D050 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : extracellular adenosine * serum colony-stimulating activity * interleukin -6 Subject RIV: BO - Biophysics Impact factor: 1.505, year: 2007

  8. Effect of adenosine receptors on 3, 4 methylene dioxy methamphetamine induced hyperthermic, neuroinflammatory and neurotoxic effects in mouse brain

    Khairnar, Amit S.

    2010-01-01

    Previous studies of ours and other groups in mice have shown that 3, 4 Methylenedioxymethamphetamine (MDMA, ecstasy) produces neurotoxic damage to dopaminergic neurons and neuroinflammation and caffeine, an adenosine A1/A2A antagonist enhances glial activation induced by MDMA, suggesting potential facilitation of neurodegenerative processes. In the present study we want to investigate effect of caffeine on MDMA induced dopaminergic neurotoxicity in adult mice, whereas selective A1 ( DPCPX ) a...

  9. MicroRNA-146b-3p Regulates Retinal Inflammation by Suppressing Adenosine Deaminase-2 in Diabetes

    Sadanand Fulzele

    2015-01-01

    Full Text Available Hyperglycemia- (HG- Amadori-glycated albumin- (AGA- induced activation of microglia and monocytes and their adherence to retinal vascular endothelial cells contribute to retinal inflammation leading to diabetic retinopathy (DR. There is a great need for early detection of DR before demonstrable tissue damages become irreversible. Extracellular adenosine, required for endogenous anti-inflammation, is regulated by the interplay of equilibrative nucleoside transporter with adenosine deaminase (ADA and adenosine kinase. ADA, including ADA1 and ADA2, exists in all organisms. However, because ADA2 gene has not been identified in mouse genome, how diabetes alters adenosine-dependent anti-inflammation remains unclear. Studies of pig retinal microglia and human macrophages revealed a causal role of ADA2 in inflammation. Database search suggested miR-146b-3p recognition sites in the 3′-UTR of ADA2 mRNA. Coexpression of miR-146b-3p, but not miR-146-5p or nontargeting miRNA, with 3′-UTR of the ADA2 gene was necessary to suppress a linked reporter gene. In the vitreous of diabetic patients, decreased miR-146b-3p is associated with increased ADA2 activity. Ectopic expression of miR-146b-3p suppressed ADA2 expression, activity, and TNF-α release in the AGA-treated human macrophages. These results suggest a regulatory role of miR-146b-3p in diabetes related retinal inflammation by suppressing ADA2.

  10. Inhibition of adenosine diphosphate-induced platelet aggregation by alpha-lipoic acid and dihydroquercetin in vitro

    Ivan S Ivanov; Sidehmenova, Anastasia V.; Vera I Smol′yakova; Chernysheva, Galina A.; Plotnikov, Mark B.

    2014-01-01

    Objectives: To investigate the antiplatelet activity of alpha-lipoic acid (α-LA) and dihydroquercetin (DHQ). Materials and Methods: Antiplatelet activity of the α-LA and DHQ was evaluated in rich platelet plasma of rat. The platelet aggregation was induced by adenosine diphosphate (ADP) in concentration of 4 Χ 10 -5 Μ. Results: α-LA and DHQ inhibited platelet aggregation in concentration-dependent manner. The antiplatelet activity of α-LA was more pronounced than DHQ. DHQ also increas...

  11. Angiographic correlations of patients with small vessel disease diagnosed by adenosine-stress cardiac magnetic resonance imaging

    Scheck Roland; Hoefling Berthold; Ali Eman; Klos Markus; Pilz Guenter; Bernhardt Peter

    2008-01-01

    Abstract Cardiac magnetic resonance imaging (CMR) with adenosine-stress myocardial perfusion is gaining importance for the detection and quantification of coronary artery disease (CAD). However, there is little knowledge about patients with CMR-detected ischemia, but having no relevant stenosis as seen on coronary angiography (CA). The aims of our study were to characterize these patients by CMR and CA and evaluate correlations and potential reasons for the ischemic findings. 73 patients with...

  12. Roles of Adenosine and Serotonin Receptors on the Antinociception of Sildenafil in the Spinal Cord of Rats

    Lee, Hyung Gon; Kim, Woong Mo; Park, Cheon Hee; Yoon, Myung Ha

    2010-01-01

    Purpose The phosphodiesterase 5 inhibitor sildenafil has antinociceptive effects, mediated by an increase in cGMP. This study examined the role of spinal adenosine and serotonin receptors played in the antinociceptive effects of intrathecal sildenafil. Materials and Methods Intrathecal catheters were inserted into the subarachnoid space of Sprague-Dawley male rats as a drug delivery device. Pain was induced by injecting formalin into the plantar surface of rats and observing nociceptive behav...

  13. Recombinant Mouse PAP Has pH-Dependent Ectonucleotidase Activity and Acts through A1-Adenosine Receptors to Mediate Antinociception

    Sowa, Nathaniel A.; Kunjumon I. Vadakkan; Zylka, Mark J.

    2009-01-01

    Prostatic acid phosphatase (PAP) is expressed in nociceptive neurons and functions as an ectonucleotidase. When injected intraspinally, the secretory isoforms of human and bovine PAP protein have potent and long-lasting antinociceptive effects that are dependent on A1-adenosine receptor (A1R) activation. In this study, we purified the secretory isoform of mouse (m)PAP using the baculovirus expression system to determine if recombinant mPAP also had antinociceptive properties. We found that mP...

  14. Adenosine-mediated inhibition of platelet aggregation by acadesine. A novel antithrombotic mechanism in vitro and in vivo.

    Bullough, D A; Zhang, C.; Montag, A; Mullane, K. M.; Young, M A

    1994-01-01

    Inhibition of platelet aggregation by acadesine was evaluated both in vitro and ex vivo in human whole blood using impedance aggregometry, as well as in vivo in a canine model of platelet-dependent cyclic coronary flow reductions. In vitro, incubation of acadesine in whole blood inhibited ADP-induced platelet aggregation by 50% at 240 +/- 60 microM. Inhibition of platelet aggregation was time dependent and was prevented by the adenosine kinase inhibitor, 5'-deoxy 5-iodotubercidin, which block...

  15. Effect of adenosine cyclophosphate combined with vitamin C therapy on electrocardiogram and serum indexes of children with viral myocarditis

    Jun Liao

    2016-01-01

    Objective:To study the effect of adenosine cyclophosphate combined with vitamin C therapy on electrocardiogram and serum indexes of children with viral myocarditis. Methods:A total of 110 cases of children with viral myocarditis treated in Pediatrics Department of our hospital from May 2012 to June 2914 were randomly divided into two groups, intervention group received adenosine cyclophosphate+vitamin C combined with conventional treatment, control group received conventional treatment, and then arrhythmia as well as serum myocardial enzymes, inflammatory mediators and signaling molecules of two groups were compared. Results: Cases with sinus tachycardia, premature beat, supraventricular tachycardia, atrioventricular block, sinus bradycardia, QT interval prolongation and ST-T segment change of intervention group were less than those of control group;serum aspartate transaminase, creatine kinase, creatine kinase isoenzyme, lactate dehydrogenase, α-hydroxybutyrate dehydrogenase, MIF, TNF-α, IL-1β, IL-6 and MCP-1 contents as well as mRNA expression levels of Rho and Rock of intervention group were lower than those of control group, and mRNA expression levels of JAK2 and STAT1 were higher than those of control group. Conclusion:Adenosine cyclophosphate combined with vitamin C therapy can prevent the occurrence of arrhythmia in children with viral myocarditis, protect myocardial cells, inhibit inflammatory response and regulate JAK2-STAT1signaling pathway and Rho/Rock signaling pathway.

  16. Cardiovascular protection and antioxidant activity of the extracts from the mycelia of Cordyceps sinensis act partially via adenosine receptors.

    Yan, Xiao-Feng; Zhang, Zhong-Miao; Yao, Hong-Yi; Guan, Yan; Zhu, Jian-Ping; Zhang, Lin-Hui; Jia, Yong-Liang; Wang, Ru-Wei

    2013-11-01

    Mycelia of cultured Cordyceps sinensis (CS) is one of the most common substitutes for natural CS and was approved for arrhythmia in China. However, the role of CS in ameliorating injury during ischemia-reperfusion (I/R) is still unclear. We examined effects of extracts from CS on I/R and investigated the possible mechanisms. Post-ischemic coronary perfusion pressure, ventricular function, and coronary flow were measured using the Langendorff mouse heart model. Oxidative stress of cardiac homogenates was performed using an ELISA. Our results indicate that CS affords cardioprotection possibly through enhanced adenosine receptor activation. Cardioprotection was demonstrated by reduced post-ischemic diastolic dysfunction and improved recovery of pressure development and coronary flow. Treatment with CS largely abrogates oxidative stress and damage in glucose- or pyruvate-perfused hearts. Importantly, observed reductions in oxidative stress [glutathione disulfide (GSSG)]/[GSSG + glutathione] and [malondialdehyde (MDA)]/[superoxide dismutase + MDA] ratios as well as the resultant damage upon CS treatment correlate with functional markers of post-ischemic myocardial outcome. These effects of CS were partially blocked by 8-ρ-sulfophenyltheophylline, an adenosine receptor antagonist. Our results demonstrate a suppressive role of CS in ischemic contracture. Meanwhile, the results also suggest pre-ischemic adenosine receptor activation may be involved in reducing contracture in hearts pretreated with CS. PMID:23192916

  17. Sesamin protects against renal ischemia reperfusion injury by promoting CD39-adenosine-A2AR signal pathway in mice

    Li, Ke; Gong, Xia; Kuang, Ge; Jiang, Rong; Wan, Jingyuan; Wang, Bin

    2016-01-01

    Ischemia reperfusion injury (IRI) is a leading cause of acute kidney injury with high morbidity and mortality due to limited therapy. Here, we examine whether sesamin attenuates renal IRI in an animal model and explore the underlying mechanisms. Male mice were subjected to right renal ischemia for 30 min followed by reperfusion for 24 h with sesamin (100 mg/kg) during which the left kidney was removed. Renal damage and function were assessed subsequently. The results showed that sesamin reduced kidney ischemia reperfusion injury, as assessed by decreased serum creatinine (Scr) and Blood urea nitrogen (BUN), alleviated tubular damage and apoptosis. In addition, sesamin inhibited neutrophils infiltration and pro-inflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-1β production in IR-preformed kidney. Notably, sesamin promoted the expression of CD39, A2A adenosine receptor (A2AAR), and A2BAR mRNA and protein as well as adenosine production. Furthermore, CD39 inhibitor or A2AR antagonist abolished partly the protection of sesamin in kidney IRI. In conclusion, sesamin could effectively protect kidney from IRI by inhibiting inflammatory responses, which might be associated with promoting the adenosine-CD39-A2AR signaling pathway. PMID:27347331

  18. Roles and mechanisms of the CD38/cyclic adenosine diphosphate ribose/Ca2+ signaling pathway

    Wenjie; Wei; Richard; Graeff; Jianbo; Yue

    2014-01-01

    Mobilization of intracellular Ca2+ stores is involved inmany diverse cell functions, including: cell proliferation;differentiation; fertilization; muscle contraction; secre-tion of neurotransmitters, hormones and enzymes;and lymphocyte activation and proliferation. Cyclic ad-enosine diphosphate ribose(cADPR) is an endogenousCa2+ mobilizing nucleotide present in many cell typesand species, from plants to animals. cADPR is formedby ADP-ribosyl cyclases from nicotinamide adenine di-nucleotide. The main ADP-ribosyl cyclase in mammalsis CD38, a multi-functional enzyme and a type Ⅱ mem-brane protein. It has been shown that many extracel-lular stimuli can induce cADPR production that leadsto calcium release or influx, establishing cADPR as asecond messenger. cADPR has been linked to a widevariety of cellular processes, but the molecular mecha-nisms regarding cADPR signaling remain elusive. Theaim of this review is to summarize the CD38/cADPR/Ca2+ signaling pathway, focusing on the recent advanc-es involving the mechanism and physiological functionsof cADPR-mediated Ca2+ mobilization.

  19. Structure-Activity Analysis of Biased Agonism at the Human Adenosine A3 Receptor.

    Baltos, Jo-Anne; Paoletta, Silvia; Nguyen, Anh T N; Gregory, Karen J; Tosh, Dilip K; Christopoulos, Arthur; Jacobson, Kenneth A; May, Lauren T

    2016-07-01

    Biased agonism at G protein-coupled receptors (GPCRs) has significant implications for current drug discovery, but molecular determinants that govern ligand bias remain largely unknown. The adenosine A3 GPCR (A3AR) is a potential therapeutic target for various conditions, including cancer, inflammation, and ischemia, but for which biased agonism remains largely unexplored. We now report the generation of bias "fingerprints" for prototypical ribose containing A3AR agonists and rigidified (N)-methanocarba 5'-N-methyluronamide nucleoside derivatives with regard to their ability to mediate different signaling pathways. Relative to the reference prototypical agonist IB-MECA, (N)-methanocarba 5'-N-methyluronamide nucleoside derivatives with significant N(6) or C2 modifications, including elongated aryl-ethynyl groups, exhibited biased agonism. Significant positive correlation was observed between the C2 substituent length (in Å) and bias toward cell survival. Molecular modeling suggests that extended C2 substituents on (N)-methanocarba 5'-N-methyluronamide nucleosides promote a progressive outward shift of the A3AR transmembrane domain 2, which may contribute to the subset of A3AR conformations stabilized on biased agonist binding. PMID:27136943

  20. Triazoloquinazolines as Human A3 Adenosine Receptor Antagonists: A QSAR Study

    Dae-Sil Lee

    2006-11-01

    Full Text Available Multiple linear regression analysis was performed on the quantitative structure-activity relationships (QSAR of the triazoloquinazoline adenosine antagonists for human A3receptors. The data set used for the QSAR analysis encompassed the activities of 33triazoloquinazoline derivatives and 72 physicochemical descriptors. A template moleculewas derived using the known molecular structure for one of the compounds when bound tothe human A2B receptor, in which the amide bond was in a cis-conformation. All the testcompounds were aligned to the template molecule. In order to identify a reasonable QSARequation to describe the data set, we developed a multiple linear regression program thatexamined every possible combination of descriptors. The QSAR equation derived from thisanalysis indicates that the spatial and electronic effects is greater than that of hydrophobiceffects in binding of the antagonists to the human A3 receptor. It also predicts that a largesterimol length parameter is advantageous to activity, whereas large sterimol widthparameters and fractional positive partial surface areas are nonadvatageous.

  1. Measurement and interpretation of microbial adenosine tri-phosphate (ATP) in aquatic environments.

    Hammes, Frederik; Goldschmidt, Felix; Vital, Marius; Wang, Yingying; Egli, Thomas

    2010-07-01

    There is a widespread need for cultivation-free methods to quantify viability of natural microbial communities in aquatic environments. Adenosine tri-phosphate (ATP) is the energy currency of all living cells, and therefore a useful indicator of viability. A luminescence-based ATP kit/protocol was optimised in order to detect ATP concentrations as low as 0.0001 nM with a standard deviation of water samples from a variety of aquatic environments (drinking water, groundwater, bottled water, river water, lake water and wastewater effluent) were analysed for extracellular ATP and microbial ATP in comparison with flow-cytometric (FCM) parameters. Microbial ATP concentrations ranged between 3% and 97% of total ATP concentrations, and correlated well (R(2)=0.8) with the concentrations of intact microbial cells (after staining with propidium iodide). From this correlation, we calculated an average ATP-per-cell value of 1.75x10(-10)nmol/cell. An even better correlation (R(2)=0.88) was observed between intact biovolume (derived from FCM scatter data) and microbial ATP concentrations, and an average ATP-per-biovolume value of 2.95x10(-9)nmol/microm(3) was calculated. These results support the use of ATP analysis for both routine monitoring and research purposes, and contribute towards a better interpretation of ATP data. PMID:20605621

  2. Adenosine Monophosphate-Activated Protein Kinase (AMPK) as a Diverse Therapeutic Target: A Computational Perspective.

    Ramesh, M; Vepuri, Suresh B; Oosthuizen, Frasia; Soliman, Mahmoud E

    2016-02-01

    Adenosine monophosphate-activated protein kinase (AMPK) is viewed as a privileged therapeutic target for several diseases such as cancer, diabetes, inflammation, obesity, etc. In addition, AMPK has entered the limelight of current drug discovery with its evolution as a key metabolic regulator. AMPK also plays a key role in the maintenance of cellular energy homeostasis. Structurally, AMPK is a heterotrimeric protein, which consists of three protein subunits (α, β, and γ). The crystal structure of AMPK was solved, and several computational studies including homology modeling, molecular docking, molecular dynamics, and QSAR have been reported in order to explore the structure and function of this diverse therapeutic target. In this review, we present a comprehensive up-to-date overview on the computational and molecular modeling approaches that have been carried out on AMPK in order to understand its structure, function, dynamics, and its drug binding landscape. Information provided in this review would be of great interest to a wide pool of researchers involved in the design of new molecules against various diseases where AMPK plays a predominant role. Graphical Abstract ᅟ. PMID:26541160

  3. Computational study of the binding modes of caffeine to the adenosine A2A receptor.

    Liu, Yuli; Burger, Steven K; Ayers, Paul W; Vöhringer-Martinez, Esteban

    2011-12-01

    Using the recently solved crystal structure of the human adenosine A(2A) receptor, we applied MM/PBSA to compare the binding modes of caffeine with those of the high-affinity selective antagonist ZM241385. MD simulations were performed in the environment of the lipid membrane bilayer. Four low-energy binding modes of caffeine-A(2A) were found, all of which had similar energies. Assuming an equal contribution of each binding mode of caffeine, the computed binding free energy difference between caffeine and ZM241385 is -2.4 kcal/mol, which compares favorably with the experimental value, -3.6 kcal/mol. The configurational entropy contribution of -0.9 kcal/mol from multiple binding modes of caffeine helps explain how a small molecule like caffeine can compete with a significantly larger molecule, ZM241385, which can form many more interactions with the receptor. We also performed residue-wise energy decomposition and found that Phe168, Leu249, and Ile274 contribute most significantly to the binding modes of caffeine and ZM241385. PMID:21970461

  4. Detection of adenosine 5'-triphosphate by fluorescence variation of oligonucleotide-templated silver nanoclusters.

    Lee, Jennifer Daneen; Cang, Jinshun; Chen, Ying-Chieh; Chen, Wei-Yu; Ou, Chung-Mao; Chang, Huan-Tsung

    2014-08-15

    Oligonucleotide-templated Ag nanoclusters (DNA-Ag NCs) prepared from AgNO3 using an oligonucleotide (5'-TAACCCCTAACCCCT-3') as a template and NaBH4 as a reducing agent have been used for sensing of adenosine 5'-triphosphate (ATP). The fluorescence intensity and emission wavelength of DNA-Ag NCs are dependent on the pH value and ATP concentration. At pH 3.0 and 11.0, ATP shows greater effects on fluorescence of the DNA-Ag NCs. Upon increasing ATP concentration from 10 to 50μM, their emission wavelength at pH 3.0 shifts from 525 to 585nm. At pH 11.0, their fluorescence intensity (510nm) increases upon increasing ATP concentration. The circular dichroism (CD), electrospray ionization-mass spectrometry (ESI-MS), absorption, and fluorescence results indicate that ATP and pH affect the interactions between DNAs and Ag atoms, resulting in changes in their fluorescence. The DNA-Ag NCs allow detection of ATP over a concentration range of 0.1-10μM, with a limit of detection 33nM. Practicality of the DNA-Ag NCs probe has been validated with the determination of ATP concentrations in the lysate of MDA-MB-231 breast carcinoma cells. PMID:24657647

  5. ADENOSINE DEAMINASE ACTIVITY AND SERUM C-REACTIVE PROTEIN AS PROGNOSTIC MARKERS OF CHAGAS DISEASE SEVERITY

    Iván Darío BRAVO-TOBAR

    2015-10-01

    Full Text Available SUMMARY Chagas disease is a public health problem worldwide. The availability of diagnostic tools to predict the development of chronic Chagas cardiomyopathy is crucial to reduce morbidity and mortality. Here we analyze the prognostic value of adenosine deaminase serum activity (ADA and C-reactive protein serum levels (CRP in chagasic individuals. One hundred and ten individuals, 28 healthy and 82 chagasic patients were divided according to disease severity in phase I (n = 35, II (n = 29, and III (n = 18. A complete medical history, 12-lead electrocardiogram, chest X-ray, and M-mode echocardiogram were performed on each individual. Diagnosis of Chagas disease was confirmed by ELISA and MABA using recombinant antigens; ADA was determined spectrophotometrically and CRP by ELISA. The results have shown that CRP and ADA increased linearly in relation to disease phase, CRP being significantly higher in phase III and ADA at all phases. Also, CRP and ADA were positively correlated with echocardiographic parameters of cardiac remodeling and with electrocardiographic abnormalities, and negatively with ejection fraction. CRP and ADA were higher in patients with cardiothoracic index ≥ 50%, while ADA was higher in patients with ventricular repolarization disturbances. Finally, CRP was positively correlated with ADA. In conclusion, ADA and CRP are prognostic markers of cardiac dysfunction and remodeling in Chagas disease.

  6. Involvement of adenosine A2A receptors in depression and anxiety.

    Yamada, Koji; Kobayashi, Minoru; Kanda, Tomoyuki

    2014-01-01

    When administered to normal healthy patients, a nonselective adenosine A1/A2A antagonist, caffeine, tended to improve anxiety and depression at low doses and to exacerbate anxiety at high doses. Caffeine also appears to enhance anxiety-related symptoms in patients with panic disorder, and A2A receptor-deficient mice have been reported to exhibit higher anxiety-like behaviors, as well as a lower incidence of depression-like behaviors. Some selective A2A antagonists were reported to ameliorate anxiety-like behaviors in rodents, while others did not affect these behaviors. In addition, most A2A antagonists showed inhibitory effects on depression-like behaviors. The mechanisms underlying the relationship between A2A receptor antagonists and anxiety and depression remain unclear at the present time, although many studies have produced hypotheses. Given that a selective A2A receptor antagonist has recently become available for use in humans, research on the role of A2A receptors in the treatment of mental illness should progress in the near future. PMID:25175973

  7. Bond cleavages of adenosine 5'-triphosphate induced by monochromatic soft X-rays

    To investigate which type of bond is likely to be cleaved by soft X-ray exposure to an adenosine 5'-triphosphate (ATP), we observed spectral changes in X-ray absorption near edge structure (XANES) around nitrogen and oxygen K-edge of an ATP film by soft X-ray irradiation. Experiments were performed at a synchrotron soft X-ray beamline at SPring-8, Japan. The XANES spectra around the nitrogen and oxygen .K-edge slightly varied by exposure to 560 eV soft X-rays. These changes are originated from the cleavage of C-N bonds between a sugar and a nucleobase site and of C-O, P-O or O-H bond of sugar and phosphate site. From the comparison between the change in XANES intensity of σ* peak at nitrogen and that at oxygen K-edges, it is inferred that the C-O, P-O or O-H bond of sugar and phosphate is much efficiently cleaved than the C-N of N-glycoside bond by the exposure of 560 eV soft X-ray to ATP film.

  8. Adenosine Triphosphate stimulates differentiation and mineralization in human osteoblast-like Saos-2 cells.

    Cutarelli, Alessandro; Marini, Mario; Tancredi, Virginia; D'Arcangelo, Giovanna; Murdocca, Michela; Frank, Claudio; Tarantino, Umberto

    2016-05-01

    In the last years adenosine triphosphate (ATP) and subsequent purinergic system activation through P2 receptors were investigated highlighting their pivotal role in bone tissue biology. In osteoblasts ATP can regulate several activities like cell proliferation, cell death, cell differentiation and matrix mineralization. Since controversial results exist, in this study we analyzed the ATP effects on differentiation and mineralization in human osteoblast-like Saos-2 cells. We showed for the first time the altered functional activity of ATP receptors. Despite that, we found that ATP can reduce cell proliferation and stimulate osteogenic differentiation mainly in the early stages of in vitro maturation as evidenced by the enhanced expression of alkaline phosphatase (ALP), Runt-related transcription factor 2 (Runx2) and Osteocalcin (OC) genes and by the increased ALP activity. Moreover, we found that ATP can affect mineralization in a biphasic manner, at low concentrations ATP always increases mineral deposition while at high concentrations it always reduces mineral deposition. In conclusion, we show the osteogenic effect of ATP on both early and late stage activities like differentiation and mineralization, for the first time in human osteoblastic cells. PMID:27189526

  9. Hereditary overexpression of adenosine deaminase in erythrocytes: Evidence for a cis-acting mutation

    Chen, E.H. (Univ. of Michigan, Ann Arbor, MI (United States)); Tartaglia, A.P. (Albany Medical College, Albany, MI (United States)); Mitchell, B.S. (Univ. of North Carolina, Chapel Hill, NC (United States))

    1993-10-01

    Overexpression of adenosine deaminase (ADA) in red blood cells is inherited as an autosomal dominant trait and causes hemolytic anemia. The increased ADA activity in erythrocytes is due to an increase in steady-state levels of ADA mRNA of normal sequence. Increased ADA mRNA may be due to a cis-acting mutation which results in increased transcription or a loss of down-regulation during erythroid differentiation. Alternatively, it is possible that the mutation is in a trans-acting factor which interacts with normal ADA transcriptional elements to cause overexpression in red blood cells. To discriminate between a cis-acting and a trans-acting mutation, the authors took advantage of a highly polymorphic TAAA repeat located at the tail end of an Alu repeat approximately 1.1 kb upstream of the ADA gene. Using PCR to amplify this region, the authors identified five different alleles in 19 members of the family. All 11 affected individuals had an ADA allele with 12 TAAA repeats, whereas none of the 8 normal individuals did. The authors conclude that this disorder results from a cis-acting mutation in the vicinity of the ADA gene. 24 refs., 3 figs.

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

    Gemma eNavarro

    2012-04-01

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

  11. Leptin suppresses adenosine triphosphate-induced impairment of spinal cord astrocytes.

    Li, Baoman; Qi, Shuang; Sun, Guangfeng; Yang, Li; Han, Jidong; Zhu, Yue; Xia, Maosheng

    2016-10-01

    Spinal cord injury (SCI) causes long-term disability and has no clinically effective treatment. After SCI, adenosine triphosphate (ATP) may be released from neuronal cells and astrocytes in large amounts. Our previous studies have shown that the extracellular release of ATP increases the phosphorylation of cytosolic phospholipase A2 (cPLA2 ) and triggers the rapid release of arachidonic acid (AA) and prostaglandin E2 (PGE2) via the stimulation of epidermal growth factor receptor (EGFR) and the downstream phosphorylation of extracellular-regulated protein kinases 1 and 2. Leptin, a glycoprotein, induces the activation of the Janus kinase (JAK2)/signal transducers and activators of transcription-3 (Stat3) pathway via the leptin receptor. In this study, we found that 1) prolonged leptin treatment suppressed the ATP-stimulated release of AA and PGE2 from cultured spinal cord astrocytes; 2) leptin elevated the expression of caveolin-1 (Cav-1) via the JAK2/Stat3 signaling pathway; 3) Cav-1 blocked the interaction between Src and EGFR, thereby inhibiting the phosphorylation of EGFR and cPLA2 and attenuating the release of AA or PGE2; 4) pretreatment with leptin decreased ;he level of apoptosis and the release of interleukin-6 from cocultured neurons and astrocytes; and 5) leptin improved the recovery of locomotion in mice after SCI. Our results highlight leptin as a promising therapeutic agent for SCI. © 2016 Wiley Periodicals, Inc. PMID:27316329

  12. The clinical correlation of regulatory T cells and cyclic adenosine monophosphate in enterovirus 71 infection.

    Shih-Min Wang

    Full Text Available Brainstem encephalitis (BE and pulmonary edema (PE are notable complications of enterovirus 71 (EV71 infection.This study investigated the immunoregulatory characterizations of EV71 neurological complications by disease severity and milrinone treatment.Patients <18 years with virologically confirmed EV71 infections were enrolled and divided into 2 groups: the hand, foot, and mouth disease (HFMD or BE group, and the autonomic nervous system (ANS dysregulation or PE group. Cytokine and cyclic adenosine monophosphate (cAMP levels, and the regulatory T cell (Tregs profiles of the patients were determined.Patients with ANS dysregulation or PE exhibited significantly low frequency of CD4(+CD25(+Foxp3+ and CD4(+Foxp3(+ T cells compared with patients with HFMD or BE. The expression frequency of CD4-CD8- was also significantly decreased in patients with ANS dysregulation or PE. Among patients with ANS dysregulation or PE, the expression frequency of CD4+Foxp3+ increased markedly after milrinone treatment, and was associated with reduction of plasma levels IL-6, IL-8 and IL-10. Plasma concentrations of cAMP were significantly decreased in patients with ANS dysregulation or PE compared with patients with HFMD or BE; however, cAMP levels increased after milrinone treatment.These findings suggested decreased different regulatory T populations and cAMP expression correlate with increased EV71 disease severity. Improved outcome after milrinone treatment may associate with increased regulatory T populations, cAMP expression and modulation of cytokines levels.

  13. Efflux of radioactive nucleotides from mouse pancreatic islets prelabelled with 2-3H-adenosine

    Cultured mouse pancreatic islets were prelabelled with 2-3H-adenosine in order to monitor the efflux pattern of radioactivity and insulin. The outflow of radioactivity decreased continuously when the islets were perifused with glucose (1.67 mmol/l). When raising the glucose concentration to 16.7 mmol/l, there was a prompt inhibition of the radioactive efflux concomitant with an increased rate of insulin release. These effects were reversed when the high glucose challenge was withdrawn. Similar radioactive efflux patterns were obtained after addition of α-ketoisocaproic acid, leucine or pyruvate to the perifusion medium, and also when the islets were challenged with high glucose concentrations in the absence of calcium. Both antimycin A and glipizide stimulated the efflux of radioactivity, although only the addition of glipizide was accompanied by a stimulation of the insulin release. Nucleotides constituted approximately 90% of the total effluent radioactivity. Decrease in the radioactive AMP and ADP efflux due to high glucose was furthermore found to be the cause of the observed inhibition of the total radioactive efflux. The changes in radioactive efflux induced by glucose probably reflect changes in the intracellular concentrations of AMP and ADP. It is concluded that no simple correlation exists between radioactive efflux and insulin release and that changes in the intracellular concentrations of nucleotides may be an early event in the stimulus-secretion coupling of glucose-induced insulin release. (orig.)

  14. Efflux of radioactive nucleotides from mouse pancreatic islets prelabelled with 2-/sup 3/H-adenosine

    Welsh, M.

    1982-07-01

    Cultured mouse pancreatic islets were prelabelled with 2-/sup 3/H-adenosine in order to monitor the efflux pattern of radioactivity and insulin. The outflow of radioactivity decreased continuously when the islets were perifused with glucose (1.67 mmol/l). When raising the glucose concentration to 16.7 mmol/l, there was a prompt inhibition of the radioactive efflux concomitant with an increased rate of insulin release. These effects were reversed when the high glucose challenge was withdrawn. Similar radioactive efflux patterns were obtained after addition of ..cap alpha..-ketoisocaproic acid, leucine or pyruvate to the perifusion medium, and also when the islets were challenged with high glucose concentrations in the absence of calcium. Both antimycin A and glipizide stimulated the efflux of radioactivity, although only the addition of glipizide was accompanied by a stimulation of the insulin release. Nucleotides constituted approximately 90% of the total effluent radioactivity. Decrease in the radioactive AMP and ADP efflux due to high glucose was furthermore found to be the cause of the observed inhibition of the total radioactive efflux. The changes in radioactive efflux induced by glucose probably reflect changes in the intracellular concentrations of AMP and ADP. It is concluded that no simple correlation exists between radioactive efflux and insulin release and that changes in the intracellular concentrations of nucleotides may be an early event in the stimulus-secretion coupling of glucose-induced insulin release.

  15. The biochemistry and epigenetics of epilepsy: focus on adenosine and glycine

    Detlev eBoison

    2016-04-01

    Full Text Available Epilepsy, one of the most prevalent neurological conditions, presents as a complex disorder of network homeostasis characterized by spontaneous non-provoked seizures and associated comorbidities. Currently used antiepileptic drugs have been designed to suppress neuronal hyperexcitability and thereby to suppress epileptic seizures. However, the current armamentarium of antiepileptic drugs is not effective in over 30% of patients, does not affect the comorbidities of epilepsy, and does not prevent the development and progression of epilepsy (epileptogenesis. Prevention of epilepsy and its progression remains the Holy Grail for epilepsy research and therapy development, requiring novel conceptual advances to find a solution to this urgent medical need. The methylation hypothesis of epileptogenesis suggests that changes in DNA methylation are implicated in the progression of the disease. In particular, global DNA hypermethylation appears to be associated with chronic epilepsy. Clinical as well as experimental evidence demonstrates that epilepsy and its progression can be prevented by biochemical manipulations and those that target previously unrecognized epigenetic functions contributing to epilepsy development and maintenance of the epileptic state. This mini-review will discuss epigenetic mechanisms implicated in epileptogenesis and biochemical interactions between adenosine and glycine as a conceptual advance to understand the contribution of maladaptive changes in biochemistry as a major contributing factor to the development of epilepsy. New findings based on biochemical manipulation of the DNA methylome suggest that (i epigenetic mechanisms play a functional role in epileptogenesis, and (ii therapeutic reconstruction of the epigenome is an effective antiepileptogenic therapy.

  16. Untangling dopamine-adenosine receptor-receptor assembly in experimental parkinsonism in rats

    Víctor Fernández-Dueñas

    2015-01-01

    Full Text Available Parkinson’s disease (PD is a dopaminergic-related pathology in which functioning of the basal ganglia is altered. It has been postulated that a direct receptor-receptor interaction – i.e. of dopamine D2 receptor (D2R with adenosine A2A receptor (A2AR (forming D2R-A2AR oligomers – finely regulates this brain area. Accordingly, elucidating whether the pathology prompts changes to these complexes could provide valuable information for the design of new PD therapies. Here, we first resolved a long-standing question concerning whether D2R-A2AR assembly occurs in native tissue: by means of different complementary experimental approaches (i.e. immunoelectron microscopy, proximity ligation assay and TR-FRET, we unambiguously identified native D2R-A2AR oligomers in rat striatum. Subsequently, we determined that, under pathological conditions (i.e. in a rat PD model, D2R-A2AR interaction was impaired. Collectively, these results provide definitive evidence for alteration of native D2R-A2AR oligomers in experimental parkinsonism, thus conferring the rationale for appropriate oligomer-based PD treatments.

  17. Mitochondrial Damage and Apoptosis Induced by Adenosine Deaminase Inhibition and Deoxyadenosine in Human Neuroblastoma Cell Lines.

    Garcia-Gil, Mercedes; Tozzi, Maria Grazia; Balestri, Francesco; Colombaioni, Laura; Camici, Marcella

    2016-07-01

    The treatment with deoxycoformycin, a strong adenosine deaminase inhibitor, in combination with deoxyadenosine, causes apoptotic cell death of two human neuroblastoma cell lines, SH-SY5Y and LAN5. Herein we demonstrate that, in SH-SY5Y cells, this combination rapidly decreases mitochondrial reactive oxygen species and, in parallel, increases mitochondrial mass, while, later, induces nuclear fragmentation, and activation of caspase-8, -9, and -3. In previous papers we have shown that a human astrocytoma cell line, subjected to the same treatment, undergoes apoptotic death as well. Therefore, both astrocytoma and neuroblastoma cell lines undergo apoptotic death following the combined treatment with deoxycoformycin and deoxyadenosine, but several differences have been found in the mode of action, possibly reflecting a different functional and metabolic profile of the two cell lines. Overall this work indicates that the neuroblastoma cell lines, like the line of astrocytic origin, are very sensitive to purine metabolism perturbation thus suggesting new therapeutic approaches to nervous system tumors. J. Cell. Biochem. 117: 1671-1679, 2016. © 2015 Wiley Periodicals, Inc. PMID:26659614

  18. The clinical value of adenosine triphosphate stress myocardial perfusion tomography for detecting coronary artery disease

    Objective: To study the clinical value of adenosine triphosphate stress myocardial perfusion tomography imaging (ATP-MPI) in detection of coronary artery disease (CAD). Methods: There were 278 patients underwent ATP-MPI, 51 patients of them also underwent coronary angiography (CAG). Seventy-three patients underwent stress-rest myocardial perfusion tomography imaging with multi-stage submaximal exercise test (ST-MPI) and CAG serving as control group. Results: 1) Side effects: there were 11 different symptoms and atrioventricular conduction block (10 patients), sinoatrial conduction block (2 patients) occurred during ATP stress. Allopathy or interruption of ATP stress did not happen. 2) The sensitivity and specificity of ATP-MPI in detection of CAD were 97.1% and 82.4%, respectively, and those in detection of ≥50% narrowing coronary artery were 91.0% and 94.7%, respectively. 3) In patients without myocardial infarction, the sensitivity and specificity of ATP-MPI in detection of myocardial ischemia were comparable to those of ST-MPI. Conclusion: ATP-MPI is an accurate, safe modality and is comparable to ST-MPI in the detection of CAD

  19. Expression of adenosine receptors in human retinal pigment epithelium cells in vitro

    WAN Wen-juan; CUI Dong-mei; YANG Xiao; HU Jian-min; LI Chuan-xu; HU Shou-long; Klaus Trier; ZENG Jun-wen

    2011-01-01

    Background Adenosine receptors (ADORs) have been reported to play a role in experimental myopia. This study aimed to determine the distribution of ADORs in human retinal pigment epithelium (RPE) cells cultured in vitro.Methods Human RPE cells (cell line D407) were cultured in vitro. ADOR mRNA in RPE was detected by reverse transcription polymerase chain reaction. ADOR protein expression in RPE was confirmed by Western blotting analysis of cell lysates. Confocal fluorescence microscopy was used to study the subcellular distribution of ADORs.Results All four subtypes of ADORs mRNA and protein were expressed in human RPE. This was confirmed by Western blotting analysis. The ADOR subtypes were differently distributed within the cells. ADORA1 was expressed in nucleus, perinucleus and cytoplasm of RPE. ADORA2A was concentrated mainly in one side of the perinucleus and cytoplasm of RPE. ADORA2B was strongly expressed in the nucleus, perinucleus and the cytoplasm, and ADORA3 was expressed weakly in the cytoplasm of RPE.Conclusions ADORs are expressed in human RPE. The different distribution at the subcellular level suggests different functions of ADOR subtypes.

  20. Gene expression and function of adenosine A(2A) receptor in the rat carotid body.

    Kobayashi, S; Conforti, L; Millhorn, D E

    2000-08-01

    The present study was undertaken to determine whether rat carotid bodies express adenosine (Ado) A(2A) receptors and whether this receptor is involved in the cellular response to hypoxia. Our results demonstrate that rat carotid bodies express the A(2A) and A(2B) Ado receptor mRNAs but not the A(1) or A(3) receptor mRNAs as determined by reverse transcriptase-polymerase chain reaction. In situ hybridization confirmed the expression of the A(2A) receptor mRNA. Immunohistochemical studies further showed that the A(2A) receptor is expressed in the carotid body and that it is colocalized with tyrosine hydroxylase in type I cells. Whole cell voltage-clamp studies using isolated type I cells showed that Ado inhibited the voltage-dependent Ca(2+) currents and that this inhibition was abolished by the selective A(2A) receptor antagonist ZM-241385. Ca(2+) imaging studies using fura 2 revealed that exposure to severe hypoxia induced elevation of intracellular Ca(2+) concentration ([Ca(2+)](i)) in type I cells and that extracellularly applied Ado significantly attenuated the hypoxia-induced elevation of [Ca(2+)](i). Taken together, our findings indicate that A(2A) receptors are present in type I cells and that activation of A(2A) receptors modulates Ca(2+) accumulation during hypoxia. This mechanism may play a role in regulating intracellular Ca(2+) homeostasis and cellular excitability during hypoxia. PMID:10926550

  1. Outcome of hematopoietic stem cell transplantation for adenosine deaminase-deficient severe combined immunodeficiency.

    Hassan, Amel; Booth, Claire; Brightwell, Alex; Allwood, Zoe; Veys, Paul; Rao, Kanchan; Hönig, Manfred; Friedrich, Wilhelm; Gennery, Andrew; Slatter, Mary; Bredius, Robbert; Finocchi, Andrea; Cancrini, Caterina; Aiuti, Alessandro; Porta, Fulvio; Lanfranchi, Arnalda; Ridella, Michela; Steward, Colin; Filipovich, Alexandra; Marsh, Rebecca; Bordon, Victoria; Al-Muhsen, Saleh; Al-Mousa, Hamoud; Alsum, Zobaida; Al-Dhekri, Hasan; Al Ghonaium, Abdulaziz; Speckmann, Carsten; Fischer, Alain; Mahlaoui, Nizar; Nichols, Kim E; Grunebaum, Eyal; Al Zahrani, Daifulah; Roifman, Chaim M; Boelens, Jaap; Davies, E Graham; Cavazzana-Calvo, Marina; Notarangelo, Luigi; Gaspar, H Bobby

    2012-10-25

    Deficiency of the purine salvage enzyme adenosine deaminase leads to SCID (ADA-SCID). Hematopoietic cell transplantation (HCT) can lead to a permanent cure of SCID; however, little data are available on outcome of HCT for ADA-SCID in particular. In this multicenter retrospective study, we analyzed outcome of HCT in 106 patients with ADA-SCID who received a total of 119 transplants. HCT from matched sibling and family donors (MSDs, MFDs) had significantly better overall survival (86% and 81%) in comparison with HCT from matched unrelated (66%; P HCT, nonengraftment was a major problem. Long-term immune recovery showed that regardless of transplant type, overall T-cell numbers were similar, although a faster rate of T-cell recovery was observed after MSD/MFD HCT. Humoral immunity and donor B-cell engraftment was achieved in nearly all evaluable surviving patients and was seen even after unconditioned HCT. These data detail for the first time the outcomes of HCT for ADA-SCID and show that, if patients survive HCT, long-term cellular and humoral immune recovery is achieved. PMID:22791287

  2. Immobilized polyphosphate kinase: preparation, properties, and potential for use in adenosine 5'-triphosphate regeneration

    Polyphosphate kinase partially purified from Escherichia coli, has been immobilized on glutaraldehyde-activated aminoethyl cellulose with a 10% retention of enzymatic activity. The immobilized enzyme can carry out the synthesis of ATP from ADP, using long-chain inorganic polyphosphate as a phosphoryl donor. Chromatographic analyses of the product mixture produced from ADP and [32P]polyphosphate demonstrated that 98% of the 32P was incorporated into ATP, indicating that the immobilized polyphosphate kinase is substantially free from contaminating polyphosphate phosphohydrolase, adenosine triphosphatase, and adenylate kinase. Immobilized polyphosphate kinase loses no activity when stored in an aqueous suspension for 2 months at 5 degrees C or for 1-2 weeks at 25 degrees C. It may be stored indefinitely as a lyophilized powder at -10 degrees C. Michaelis constants for ADP and polyphosphate were determined to be 160 and 120 microM, respectively, for the immobilized enzyme. A small-batch reactor was found to produce ATP linearly with time up to 65% conversion of polyphosphate into ATP and to attain greater than 85% conversion to ATP at equilibrium. The ease of purification and immobilization of E. coli polyphosphate kinase, its storage stability, the purity and yield of its ATP product, and the low values of the Michaelis constants for its substrates make it a highly promising enzyme for ATP regeneration

  3. (/sup 3/H)nitrobenzylthioinosine binding as a probe for the study of adenosine uptake sites in brain

    Marangos, P.J.; Patel, J.; Clark-Rosenberg, R.; Martino, A.M.

    1982-07-01

    The binding of the potent adenosine uptake inhibitor (/sup 3/H)nitrobenzylthioinosine ((/sup 3/H)NBI) to brain membrane fractions was investigated. Reversible, saturable, specific, high-affinity binding was demonstrated in both rat and human brain. The KD in both was 0.15 nM with Bmax values of 140-200 fmol/mg protein. Linear Scatchard plots were routinely obtained, indicating a homogeneous population of binding sites in brain. The highest density of binding sites was found in the caudate and hypothalamus in both species. The binding site was heat labile and trypsin sensitive. Binding was also decreased by incubation of the membranes in 0.05% Triton X-100 and by treatment with dithiothreitol and iodoacetamide. Of the numerous salt and metal ions tested, only copper and zinc had significant effects on (/sup 3/H)NBI binding. The inhibitory potencies of copper and zinc were IC50 . 160 microM and 6 mM, respectively. Subcellular distribution studies revealed a high percentage of the (/sup 3/H)NBI binding sites on synaptosomes, indicating that these sites were present in the synaptic region. A study of the tissue distribution of the (/sup 3/H)NBI sites revealed very high densities of binding in erythrocyte, lung, and testis, with much lower binding densities in brain, kidney, liver, muscle, and heart. The binding affinity in the former group was approximately 1.5 nM, whereas that in the latter group was 0.15 nM, suggesting two types of binding sites. The pharmacologic profile of (/sup 3/H)NBI binding was consistent with its function as the adenosine transport site, distinct from the adenosine receptor, since thiopurines were very potent inhibitors of binding whereas adenosine receptor ligands, such as cyclohexyladenosine and 2-chloroadenosine, were three to four orders of magnitude less potent. (/sup 3/H)NBI binding in brain should provide a useful probe for the study of adenosine transport in the brain.

  4. Selective adenosine A2A receptor agonists and antagonists protect against spinal cord injury through peripheral and central effects

    Esposito Emanuela

    2011-04-01

    Full Text Available Abstract Background Permanent functional deficits following spinal cord injury (SCI arise both from mechanical injury and from secondary tissue reactions involving inflammation. Enhanced release of adenosine and glutamate soon after SCI represents a component in the sequelae that may be responsible for resulting functional deficits. The role of adenosine A2A receptor in central ischemia/trauma is still to be elucidated. In our previous studies we have demonstrated that the adenosine A2A receptor-selective agonist CGS21680, systemically administered after SCI, protects from tissue damage, locomotor dysfunction and different inflammatory readouts. In this work we studied the effect of the adenosine A2A receptor antagonist SCH58261, systemically administered after SCI, on the same parameters. We investigated the hypothesis that the main action mechanism of agonists and antagonists is at peripheral or central sites. Methods Spinal trauma was induced by extradural compression of SC exposed via a four-level T5-T8 laminectomy in mouse. Three drug-dosing protocols were utilized: a short-term systemic administration by intraperitoneal injection, a chronic administration via osmotic minipump, and direct injection into the spinal cord. Results SCH58261, systemically administered (0.01 mg/kg intraperitoneal. 1, 6 and 10 hours after SCI, reduced demyelination and levels of TNF-α, Fas-L, PAR, Bax expression and activation of JNK mitogen-activated protein kinase (MAPK 24 hours after SCI. Chronic SCH58261 administration, by mini-osmotic pump delivery for 10 days, improved the neurological deficit up to 10 days after SCI. Adenosine A2A receptors are physiologically expressed in the spinal cord by astrocytes, microglia and oligodendrocytes. Soon after SCI (24 hours, these receptors showed enhanced expression in neurons. Both the A2A agonist and antagonist, administered intraperitoneally, reduced expression of the A2A receptor, ruling out the possibility that the

  5. Chronic hypoxia reduces adenosine A2A receptor-mediated inhibition of calcium current in rat PC12 cells via downregulation of protein kinase A.

    Kobayashi, S; Beitner-Johnson, D; Conforti, L; Millhorn, D E

    1998-10-15

    1. Adenosine has been shown to decrease Ca2+ current (ICa) and attenuate the hypoxia-induced enhancement of intracellular free Ca2+ ([Ca2+]i) in oxygen-sensitive rat phaeochromocytoma (PC12) cells. These effects are mediated via the adenosine A2A receptor and protein kinase A (PKA). The current study was undertaken to determine the effects of adenosine on Ca2+ current and hypoxia-induced change in [Ca2+]i during chronic hypoxia. 2. Whole cell patch-clamp studies revealed that the effect of adenosine on ICa was significantly reduced when PC12 cells were exposed to hypoxia (10 % O2) for 24 and 48 h. 3. Ca2+ imaging studies using fura-2 revealed that the anoxia-induced increase in [Ca2+]i was significantly enhanced when PC12 cells were exposed to 10 % O2 for up to 48 h. In contrast, the inhibitory effects of adenosine on anoxia-induced elevation of [Ca2+]i was significantly blunted in PC12 cells exposed to hypoxia for 48 h. 4. Northern blot analysis revealed that mRNA for the A2A receptor, which is the only adenosine receptor subtype expressed in PC12 cells, was significantly upregulated by hypoxia. Radioligand binding analysis with [3H]CGS21680, a selective A2A receptor ligand, showed that the number of adenosine A2A receptor binding sites was similarly increased during exposure to 10% O2 for 48 h. 5. PKA enzyme activity was significantly inhibited when PC12 cells were exposed to 10% O2 for 24 and 48 h. However, we found that hypoxia failed to induce change in adenosine- and forskolin-stimulated adenylate cyclase enzyme activity. Chronic hypoxia also did not alter the immunoreactivity level of the G protein Gsalpha, an effector of the A2 signalling pathway. 6. Whole cell patch-clamp analysis showed that the effect of 8-bromo-cAMP, an activator of PKA, on ICa was significantly attenuated during 48 h exposure to 10% O2.7. We conclude therefore that the reduced effect of adenosine on ICa and [Ca2+]i in PC12 cells exposed to chronic hypoxia is due to hypoxia

  6. Different cellular sources and different roles of adenosine: A1 receptor-mediated inhibition through astrocytic-driven volume transmission and synapse-restricted A2A receptor-mediated facilitation of plasticity

    Cunha, Rodrigo A.

    2008-01-01

    Adenosine is a prototypical neuromodulator, which mainly controls excitatory transmission through the activation of widespread inhibitory A1 receptors and synaptically located A2A receptors. It was long thought that the predominant A1 receptor-meditated modulation by endogenous adenosine was a homeostatic process intrinsic to the synapse. New studies indicate that endogenous extracellular adenosine is originated as a consequence of the release of gliotransmitters, namely ATP, which sets a glo...

  7. Hyperglycemia alters E-NTPDases, ecto-5'-nucleotidase, and ectosolic and cytosolic adenosine deaminase activities and expression from encephala of adult zebrafish (Danio rerio).

    Capiotti, Katiucia Marques; Siebel, Anna Maria; Kist, Luiza Wilges; Bogo, Maurício Reis; Bonan, Carla Denise; Da Silva, Rosane Souza

    2016-06-01

    Hyperglycemia is the main feature for the diagnosis of diabetes mellitus (DM). Some studies have demonstrated the relationship between DM and dysfunction on neurotransmission systems, such as the purinergic system. In this study, we evaluated the extracellular nucleotide hydrolysis and adenosine deamination activities from encephalic membranes of hyperglycemic zebrafish. A significant decrease in ATP, ADP, and AMP hydrolyses was observed at 111-mM glucose-treated group, which returned to normal levels after 7 days of glucose withdrawal. A significant increase in ecto-adenosine deaminase activity was observed in 111-mM glucose group, which remain elevated after 7 days of glucose withdrawal. The soluble-adenosine deaminase activity was significantly increased just after 7 days of glucose withdrawal. We also evaluated the gene expressions of ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases), ecto-5'-nucleotidase, ADA, and adenosine receptors from encephala of adult zebrafish. The entpd 2a.1, entpd 2a.2, entpd 3, and entpd 8 mRNA levels from encephala of adult zebrafish were decreased in 111-mM glucose-treated and glucose withdrawal groups. The gene expressions of adenosine receptors (adora 1 , adora 2aa , adora 2ab , and adora 2b ) were decreased in 111-mM glucose-treated and glucose withdrawal groups. The gene expression of ADA (ada 2a.1) was decreased in glucose withdrawal group. Maltodextrin, used as a control, did not affect the expression of adenosine receptors, ADA and E-NTPDases 2, 3, and 8, while the expression of ecto-5'-nucleotidase was slightly increased and the E-NTPDases 1 decreased. These findings demonstrated that hyperglycemia might affect the ecto-nucleotidase and adenosine deaminase activities and gene expression in zebrafish, probably through a mechanism involving the osmotic effect, suggesting that the modifications caused on purinergic system may also contribute to the diabetes-induced progressive cognitive impairment. PMID:26769247

  8. A New Activity of Anti-HIV and Anti-tumor Protein GAP31: DNA Adenosine Glycosidase – Structural and Modeling Insight into its Functions

    Li, H.; Huang, P; Zhang, D; Sun, Y; Chen, H; Zhang, J; Huang, P; Kong, X; Lee-Huang, S

    2010-01-01

    We report here the high-resolution atomic structures of GAP31 crystallized in the presence of HIV-LTR DNA oligonucleotides systematically designed to examine the adenosine glycosidase activity of this anti-HIV and anti-tumor plant protein. Structural analysis and molecular modeling lead to several novel findings. First, adenine is bound at the active site in the crystal structures of GAP31 to HIV-LTR duplex DNA with 5' overhanging adenosine ends, such as the 3'-processed HIV-LTR DNA but not to DNA duplex with blunt ends. Second, the active site pocket of GAP31 is ideally suited to accommodate the 5' overhanging adenosine of the 3'-processed HIV-LTR DNA and the active site residues are positioned to perform the adenosine glycosidase activity. Third, GAP31 also removes the 5'-end adenine from single-stranded HIV-LTR DNA oligonucleotide as well as any exposed adenosine, including that of single nucleotide dAMP but not from AMP. Fourth, GAP31 does not de-purinate guanosine from di-nucleotide GT. These results suggest that GAP31 has DNA adenosine glycosidase activity against accessible adenosine. This activity is distinct from the generally known RNA N-glycosidase activity toward the 28S rRNA. It may be an alternative function that contributes to the antiviral and anti-tumor activities of GAP31. These results provide molecular insights consistent with the anti-HIV mechanisms of GAP31 in its inhibition on the integration of viral DNA into the host genome by HIV-integrase as well as irreversible topological relaxation of the supercoiled viral DNA.

  9. A new activity of anti-HIV and anti-tumor protein GAP31: DNA adenosine glycosidase - Structural and modeling insight into its functions

    Li, Hui-Guang [Department of Biochemistry, New York University School of Medicine, New York, NY 10016 (United States); Huang, Philip L. [American Biosciences, Boston, MA 02114 (United States); Zhang, Dawei; Sun, Yongtao [Department of Biochemistry, New York University School of Medicine, New York, NY 10016 (United States); Chen, Hao-Chia [Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892 (United States); Zhang, John [Department of Chemistry, New York University, New York, NY 10003 (United States); Huang, Paul L. [Department of Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA 02114 (United States); Kong, Xiang-Peng, E-mail: xiangpeng.kong@med.nyu.edu [Department of Biochemistry, New York University School of Medicine, New York, NY 10016 (United States); Lee-Huang, Sylvia, E-mail: sylvia.lee-huang@med.nyu.edu [Department of Biochemistry, New York University School of Medicine, New York, NY 10016 (United States)

    2010-01-01

    We report here the high-resolution atomic structures of GAP31 crystallized in the presence of HIV-LTR DNA oligonucleotides systematically designed to examine the adenosine glycosidase activity of this anti-HIV and anti-tumor plant protein. Structural analysis and molecular modeling lead to several novel findings. First, adenine is bound at the active site in the crystal structures of GAP31 to HIV-LTR duplex DNA with 5' overhanging adenosine ends, such as the 3'-processed HIV-LTR DNA but not to DNA duplex with blunt ends. Second, the active site pocket of GAP31 is ideally suited to accommodate the 5' overhanging adenosine of the 3'-processed HIV-LTR DNA and the active site residues are positioned to perform the adenosine glycosidase activity. Third, GAP31 also removes the 5'-end adenine from single-stranded HIV-LTR DNA oligonucleotide as well as any exposed adenosine, including that of single nucleotide dAMP but not from AMP. Fourth, GAP31 does not de-purinate guanosine from di-nucleotide GT. These results suggest that GAP31 has DNA adenosine glycosidase activity against accessible adenosine. This activity is distinct from the generally known RNA N-glycosidase activity toward the 28S rRNA. It may be an alternative function that contributes to the antiviral and anti-tumor activities of GAP31. These results provide molecular insights consistent with the anti-HIV mechanisms of GAP31 in its inhibition on the integration of viral DNA into the host genome by HIV-integrase as well as irreversible topological relaxation of the supercoiled viral DNA.

  10. A new activity of anti-HIV and anti-tumor protein GAP31: DNA adenosine glycosidase - Structural and modeling insight into its functions

    We report here the high-resolution atomic structures of GAP31 crystallized in the presence of HIV-LTR DNA oligonucleotides systematically designed to examine the adenosine glycosidase activity of this anti-HIV and anti-tumor plant protein. Structural analysis and molecular modeling lead to several novel findings. First, adenine is bound at the active site in the crystal structures of GAP31 to HIV-LTR duplex DNA with 5' overhanging adenosine ends, such as the 3'-processed HIV-LTR DNA but not to DNA duplex with blunt ends. Second, the active site pocket of GAP31 is ideally suited to accommodate the 5' overhanging adenosine of the 3'-processed HIV-LTR DNA and the active site residues are positioned to perform the adenosine glycosidase activity. Third, GAP31 also removes the 5'-end adenine from single-stranded HIV-LTR DNA oligonucleotide as well as any exposed adenosine, including that of single nucleotide dAMP but not from AMP. Fourth, GAP31 does not de-purinate guanosine from di-nucleotide GT. These results suggest that GAP31 has DNA adenosine glycosidase activity against accessible adenosine. This activity is distinct from the generally known RNA N-glycosidase activity toward the 28S rRNA. It may be an alternative function that contributes to the antiviral and anti-tumor activities of GAP31. These results provide molecular insights consistent with the anti-HIV mechanisms of GAP31 in its inhibition on the integration of viral DNA into the host genome by HIV-integrase as well as irreversible topological relaxation of the supercoiled viral DNA.

  11. Single photon emission computed tomography with thallium-201 during adenosine-induced coronary hyperemia: Correlation with coronary arteriography, exercise thallium imaging and two-dimensional echocardiography

    The feasibility, safety and diagnostic accuracy of single photon emission computed tomography (SPECT) with thallium-201 imaging during adenosine-induced coronary hyperemia were evaluated in 53 patients with and 7 without coronary artery disease proved by coronary angiography. Adenosine was infused intravenously at a dose of 0.14 mg/kg body weight per min for 6 min and thallium was injected at 3 min. Adenosine caused an increase in heart rate (68 +/- 12 at baseline versus 87 +/- 18 beats/min at peak effect, p less than 0.0001) but no change in blood pressure. The sensitivity and specificity were 92% (95% confidence intervals 81% to 98%) and 100% (95% confidence intervals 59% to 100%), respectively; 20 (61%) of 33 patients with multivessel coronary artery disease were also correctly identified. In 30 patients, the predictive accuracy of adenosine thallium imaging was slightly higher than that of exercise SPECT thallium imaging (90% versus 80%, p = NS) (95% confidence intervals 72% to 97% and 61% to 92%, respectively). In 25 patients, two-dimensional echocardiography during adenosine infusion disclosed a new wall motion abnormality in 2 (10%) of 20 patients with coronary artery disease; 80% of these patients had reversible thallium defects (p less than 0.001). Side effects were mild and transient; aminophylline was used in only three patients. Thus, adenosine SPECT thallium imaging provides a high degree of accuracy in the diagnosis of coronary artery disease. The results are comparable with those of exercise SPECT thallium imaging. Most reversible defects in the adenosine study are not associated with any transient wall motion abnormality

  12. Autoimmune dysregulation and purine metabolism in adenosine deaminase (ADA-deficiency

    Aisha Vanessa Sauer

    2012-08-01

    Full Text Available Genetic defects in the adenosine deaminase (ADA gene are among the most common causes for severe combined immunodeficiency (SCID. ADA-SCID patients suffer from lymphopenia, severely impaired cellular and humoral immunity, failure to thrive and recurrent infections. Currently available therapeutic options for this otherwise fatal disorder include bone marrow transplantation (BMT, enzyme replacement therapy with bovine ADA (PEG-ADA or hematopoietic stem cell gene therapy (HSC-GT. Although varying degrees of immune reconstitution can be achieved by these treatments, breakdown of tolerance is a major concern in ADA-SCID. Immune dysregulation such as autoimmune hypothyroidism, diabetes mellitus, hemolytic anemia, and immune thrombocytopenia are frequently observed in milder forms of the disease. However, several reports document similar complications also in patients on long-term PEG-ADA and after BMT or GT treatment.A skewed repertoire and decreased immune functions have been implicated in autoimmunity observed in certain B-cell and/or T-cell immunodeficiencies, but it remains unclear to what extent specific mechanisms of tolerance are affected in ADA deficiency. Herein we provide an overview about ADA-SCID and the autoimmune manifestations reported in these patients before and after treatment. We also assess the value of the ADA-deficient mouse model as a useful tool to study both immune and metabolic disease mechanisms. With focus on regulatory T and B cells we discuss the lymphocyte subpopulations particularly prone to contribute to the loss of self-tolerance and onset of autoimmunity in ADA deficiency. Moreover we address which aspects of immune dysregulation are specifically related to alterations in purine metabolism caused by the lack of ADA and the subsequent accumulation of metabolites with immunomodulatory properties.

  13. Hemodynamic significance of coronary stenosis by vessel attenuation measurement on CT compared with adenosine perfusion MRI

    Dekker, Martijn A.M. den; Pelgrim, Gert Jan; Pundziute, Gabija; Heuvel, Edwin R. van den; Oudkerk, Matthijs; Vliegenthart, Rozemarijn, E-mail: r.vliegenthart@umcg.nl

    2015-01-15

    Highlights: • The majority of anatomical coronary stenoses do not cause myocardial ischemia. • cCTA-derived CCO decrease expresses luminal density gradient across stenosis. • CCO decrease differentiates between anatomical stenoses with and without associated myocardial ischemia. • CCO decrease assessment can exclude the majority of stenoses without hemodynamic significance. - Abstract: Purpose: We assessed the association between corrected contrast opacification (CCO) based on coronary computed tomography angiography (cCTA) and inducible ischemia by adenosine perfusion magnetic resonance imaging (APMR). Methods: Sixty cardiac asymptomatic patients with extra-cardiac arterial disease (mean age 64.4 ± 7.7 years; 78% male) underwent cCTA and APMR. Luminal CT attenuation values (Hounsfield Units) were measured in coronary arteries from proximal to distal, with additional measurements across sites with >50% lumen stenosis. CCO was calculated by dividing coronary CT attenuation by descending aorta CT attenuation. A reversible perfusion defect on APMR was considered as myocardial ischemia. Results: In total, 169 coronary stenoses were found. Seven patients had 8 perfusion defects on APMR, with 11 stenoses in corresponding vessels. CCO decrease across stenoses with hemodynamic significance was 0.144 ± 0.112 compared to 0.047 ± 0.104 across stenoses without hemodynamic significance (P = 0.003). CCO decrease in lesions with and without anatomical stenosis was similar (0.054 ± 0.116 versus 0.052 ± 0.101; P = 0.89). Using 0.20 as preliminary CCO decrease cut-off, hemodynamic significance would be excluded in 82.9% of anatomical stenoses. Conclusions: CCO decrease across coronary stenosis is associated with myocardial ischemia on APMR. CCO based on common cCTA data is a novel method to assess hemodynamic significance of anatomical stenosis.

  14. Adsorption of nucleotides on biomimetic apatite: The case of adenosine 5‧ monophosphate (AMP)

    Hammami, K.; Feki, H. El; Marsan, O.; Drouet, C.

    2015-10-01

    This work investigates the interaction between the nucleotide adenosine 5‧ monophosphate molecule (AMP) and a biomimetic nanocrystalline carbonated apatite as a model for bone mineral. The analogy of the apatite phase used in this work with biological apatite was first pointed out by complementary techniques. AMP adsorption isotherms were then investigated. Obtained data were fitted to a Sips isotherm with an exponent greater than one suggesting positive cooperativity among adsorbed molecules. The data were compared to a previous study relative to the adsorption of another nucleotide, cytidine monophosphate (CMP) onto a similar substrate, evidencing some effect of the chemical nature of the nucleic base. An enhanced adsorption was observed under acidic (pH 6) conditions as opposed to pH 7.4, which parallels the case of DNA adsorption on biomimetic apatite. An estimated standard Gibbs free energy associated to the adsorption process (ΔG°ads ≅ -22 kJ/mol) intermediate between "physisorption" and "chemisorption" was found. The analysis of the solids after adsorption pointed to the preservation of the main characteristics of the apatite substrate but shifts or enhancements of Raman bands attributed to AMP showed the existence of chemical interactions involving both the phosphate and adenine parts of AMP. This contribution adds to the works conducted in view of better understanding the interaction of DNA/RNA and their constitutive nucleotides and the surface of biomimetic apatites. It could prove helpful in disciplines such as bone diagenesis (DNA/apatite interface in aged bones) or nanomedicine (setup of DNA- or RNA-loaded apatite systems). Also, the adsorption of nucleic acids on minerals like apatites could have played a role in the preservation of such biomolecules in the varying conditions known to exist at the origin of life on Earth, underlining the importance of dedicated adsorption studies.

  15. Adenosine 5′-Triphosphate Flux Through the North Inlet Marsh System †

    Chrzanowski, Thomas H.; Stevenson, L. Harold; Kjerfve, Bjorn

    1979-01-01

    The distribution, fluctuation, and short-term transport of total microbial biomass (measured as adenosine 5′-triphosphate [ATP]) was investigated in a large salt marsh creek. Hourly samples were collected synoptically for 25 h from 10 boats positioned across the 320-m width of the creek. Samples were collected from three depths ranging from 0.2 to 8.0 m. Hourly data obtained from each station were graphed, plotting depth against ATP. Subsequently, interpolated ATP values were generated for every one-tenth depth from the surface to the bottom with the use of an 11-point proportional divider. A total of 2,750 values were generated, and a mean value of 0.865 mg of ATP per m3 was determined. Maximum levels of ATP were found at high tide and minimal values were found at low tide. The distribution of ATP concentrations was found to be complex, with no suggestion of vertical stratification; however, horizontal divisions were apparent. ATP values corrected for direction of flow or velocity indicated two ebb-directed channels; however, when considered in total, there was a net import of ATP through the interface. The total import of ATP for this 25-h sampling period was calculated to be 3.58 kg, corresponding to a net transport of 39.8 mg of ATP per s through the cross section. Results suggest that detailed characterization of a creek transect in terms of ATP or any similar parameter requires the simultaneous measurements of both the concentration of the parameter in question and the velocity at the time and point from which the sample was taken. PMID:16345382

  16. Analysis of Trinitrophenylated Adenosine and Inosine by Capillary Electrophoresis and γ-Cyclodextrin-Enhanced Fluorescence Detection.

    Stephen, Terilyn K L; Guillemette, Katherine L; Green, Thomas K

    2016-08-01

    Monitoring molecules such as adenosine (Ado) and inosine (Ino) in the central nervous system has enabled the field of neuroscience to correlate molecular concentrations dynamics to neurological function, behavior, and disease. In vivo sampling techniques are commonly used to monitor these dynamics; however, many techniques are limited by the sensitivity and sample volume requirements of currently available detection methods. Here, we present a novel capillary electrophoresis-laser-induced fluorescence detection (CE-LIF) method that analyzes Ado and Ino by derivatization with 2,4,6-trinitrobenzenesulfonic acid to form fluorescent trinitrophenylated complexes of Ado (TNP-Ado) and Ino (TNP-Ino). These complexes exhibit ∼25-fold fluorescence enhancement upon the formation of inclusion complexes with γ-cyclodextrin (γ-CD). Association constants were determined as 4600 M(-1) for Ado and 1000 M(-1) for Ino by CE-LIF. The structure of the TNP-Ado:γ-CD complex was determined by 2D nuclear magnetic resonance (NMR) spectroscopy. Optimal trinitrophenylation reaction conditions and CE-LIF parameters were determined and resulted in the limit of detection of 1.6 μM for Ado and 4 μM for Ino. Ado and Ino were simultaneously quantified in homogenized rat forebrain samples to illustrate application of the technique. Simulated biological samples, desalted by ultrafiltration in the presence γ-CD, were concentrated on-capillary by large-volume sample stacking (LVSS) to achieve detection limits of 32 and 38 nM for TNP-Ado and TNP-Ino, respectively. PMID:27314490

  17. 2-Deoxy adenosine triphosphate improves contraction in human end-stage heart failure

    Moussavi-Harami, Farid; Razumova, Maria V.; Racca, Alice W.; Cheng, Yuanhua; Stempien-Otero, April; Regnier, Michael

    2014-01-01

    We are developing a novel treatment for heart failure by increasing myocardial 2 deoxy-ATP (dATP). Our studies in rodent models have shown that substitution of dATP for adenosine triphosphate (ATP) as the energy substrate in vitro or elevation of dATP in vivo increases myocardial contraction and that small increases in the native dATP pool of heart muscle are sufficient to improve cardiac function. Here we report, for the first time, the effect of dATP on human adult cardiac muscle contraction. We measured the contractile properties of chemically-demembranated multicellular ventricular wall preparations and isolated myofibrils from human subjects with end-stage heart failure. Isometric force was increased at both saturating and physiologic Ca2+ concentrations with dATP compared to ATP. This resulted in an increase in the Ca2+ sensitivity of force (pCa50) by 0.06 pCa units. The rate of force redevelopment (kTR) in demembranated wall muscle was also increased, as was the rate of contractile activation (kACT) in isolated myofibrils, indicating increased cross-bridge binding and cycling compared with ATP in failing human myocardium. These data suggest dATP could increase dP/dT and end systolic pressure in failing human myocardium. Importantly, even though the magnitude and rate of force development was increased, there was no increase in the time to 50% and 90% myofibril relaxation. These data, along with our previous studies in rodent models shows the promise of elevating myocardial dATP to enhance contraction and restore cardiac pump function. These data also support further pre-clinical evaluation of this new approach for treating heart failure. PMID:25498214

  18. Adenosine can thwart antitumor immune responses elicited by radiotherapy. Therapeutic strategies alleviating protumor ADO activities

    By studying the bioenergetic status we could show that the development of tumor hypoxia is accompanied, apart from myriad other biologically relevant effects, by a substantial accumulation of adenosine (ADO). ADO has been shown to act as a strong immunosuppressive agent in tumors by modulating the innate and adaptive immune system. In contrast to ADO, standard radiotherapy (RT) can either stimulate or abrogate antitumor immune responses. Herein, we present ADO-mediated mechanisms that may thwart antitumor immune responses elicited by RT. An overview of the generation, accumulation, and ADO-related multifaceted inhibition of immune functions, contrasted with the antitumor immune effects of RT, is provided. Upon hypoxic stress, cancer cells release ATP into the extracellular space where nucleotides are converted into ADO by hypoxia-sensitive, membrane-bound ectoenzymes (CD39/CD73). ADO actions are mediated upon binding to surface receptors, mainly A2A receptors on tumor and immune cells. Receptor activation leads to a broad spectrum of strong immunosuppressive properties facilitating tumor escape from immune control. Mechanisms include (1) impaired activity of CD4 + T and CD8 + T, NK cells and dendritic cells (DC), decreased production of immuno-stimulatory lymphokines, and (2) activation of Treg cells, expansion of MDSCs, promotion of M2 macrophages, and increased activity of major immunosuppressive cytokines. In addition, ADO can directly stimulate tumor proliferation and angiogenesis. ADO mechanisms described can thwart antitumor immune responses elicited by RT. Therapeutic strategies alleviating tumor-promoting activities of ADO include respiratory hyperoxia or mild hyperthermia, inhibition of CD39/CD73 ectoenzymes or blockade of A2A receptors, and inhibition of ATP-release channels or ADO transporters. (orig.)

  19. Oxidative Stress Biomarkers and Adenosine Deaminase over the Alopecic Area of the Patients with Alopecia Areata

    Öztürk, Perihan; Arıcan, Özer; Kurutaş, Ergül Belge; Mülayim, Kamil

    2016-01-01

    Background: Alopecia areata (AA) is an autoimmune, T-cell mediated, and chronic inflammatory disorder. The pathological mechanisms of disease are unclear, but oxidative stress may be involved. To our knowledge, no studies have examined the oxidative stress levels or biomarkers within the lesional area and skin surface in patients with AA. Similarly, adenosine deaminase (ADA) has not been characterized in AA. Aims: Therefore, we aimed to define ADA levels and the factors involved in oxidative stress from scalp-scrapes of patients with AA. Study Design: Case-control study. Method: A total of 60 patients (30 diagnosed AA patients and 30 healthy controls) were included in the study. ADA as well as oxidative stress factors, including malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were analyzed from scalp-scrapes in both groups and quantified by spectrophotometry. Results: Activities of SOD (p=0.000), CAT (p=0.033), and ADA (p=0.004) as well as levels of GSH (p=0.000) and MDA (p=0.032) in patients with AA were higher than the controls statistically significant. Conclusion: Based on these results, factors associated with oxidative stress were elevated in AA patient scalp-scrapes compared to controls and may have a defined role the disease pathogenesis. Alterations in the activities of antioxidant enzymes from AA patient scraping samples may be a local effect of elevated oxidative stress levels. In this disease, oxidative stress may affect not only hair follicle but also any layers of the skin.

  20. John Daly Lecture: Structure-guided Drug Design for Adenosine and P2Y Receptors

    Kenneth A. Jacobson

    2015-01-01

    Full Text Available We establish structure activity relationships of extracellular nucleosides and nucleotides at G protein-coupled receptors (GPCRs, e.g. adenosine receptors (ARs and P2Y receptors (P2YRs, respectively. We synthesize selective agents for use as pharmacological probes and potential therapeutic agents (e.g. A3AR agonists for neuropathic pain. Detailed structural information derived from the X-ray crystallographic structures within these families enables the design of novel ligands, guides modification of known agonists and antagonists, and helps predict polypharmacology. Structures were recently reported for the P2Y12 receptor (P2Y12R, an anti-thrombotic target. Comparison of agonist-bound and antagonist-bound P2Y12R indicates unprecedented structural plasticity in the outer portions of the transmembrane (TM domains and the extracellular loops. Nonphosphate-containing ligands of the P2YRs, such as the selective P2Y14R antagonist PPTN, are desired for bioavailability and increased stability. Also, A2AAR structures are effectively applied to homology modeling of closely related A1AR and A3AR, which are not yet crystallized. Conformational constraint of normally flexible ribose with bicyclic analogues increased the ligand selectivity. Comparison of rigid A3AR agonist congeners allows the exploration of interaction of specific regions of the nucleoside analogues with the target and off-target GPCRs, such as biogenic amine receptors. Molecular modeling predicts plasticity of the A3AR at TM2 to accommodate highly rigidified ligands. Novel fluorescent derivatives of high affinity GPCR ligands are useful tool compounds for characterization of receptors and their oligomeric assemblies. Fluorescent probes are useful for characterization of GPCRs in living cells by flow cytometry and other methods. Thus, 3D knowledge of receptor binding and activation facilitates drug discovery.

  1. Inhibition of Salmonella enterica biofilm formation using small-molecule adenosine mimetics.

    Koopman, Jacob A; Marshall, Joanna M; Bhatiya, Aditi; Eguale, Tadesse; Kwiek, Jesse J; Gunn, John S

    2015-01-01

    Biofilms have been widely implicated in chronic infections and environmental persistence of Salmonella enterica, facilitating enhanced colonization of surfaces and increasing the ability of the bacteria to be transmitted to new hosts. Salmonella enterica serovar Typhi biofilm formation on gallstones from humans and mice enhances gallbladder colonization and bacterial shedding, while Salmonella enterica serovar Typhimurium biofilms facilitate long-term persistence in a number of environments important to food, medical, and farming industries. Salmonella regulates expression of many virulence- and biofilm-related processes using kinase-driven pathways. Kinases play pivotal roles in phosphorylation and energy transfer in cellular processes and possess an ATP-binding pocket required for their functions. Many other cellular proteins also require ATP for their activity. Here we test the hypothesis that pharmacological interference with ATP-requiring enzymes utilizing adenosine mimetic compounds would decrease or inhibit bacterial biofilm formation. Through the screening of a 3,000-member ATP mimetic library, we identified a single compound (compound 7955004) capable of significantly reducing biofilm formation by S. Typhimurium and S. Typhi. The compound was not bactericidal or bacteriostatic toward S. Typhimurium or cytotoxic to mammalian cells. An ATP-Sepharose affinity matrix technique was used to discover potential protein-binding targets of the compound and identified GroEL and DeoD. Compound 7955004 was screened against other known biofilm-forming bacterial species and was found to potently inhibit biofilms of Acinetobacter baumannii as well. The identification of a lead compound with biofilm-inhibiting capabilities toward Salmonella provides a potential new avenue of therapeutic intervention against Salmonella biofilm formation, with applicability to biofilms of other bacterial pathogens. PMID:25313216

  2. Mutations in the human adenosine deaminase gene that affect protein structure and RNA splicing

    Adenosine deaminase deficiency is one cause of the genetic disease severe combined immunodeficiency. To identify mutations responsible for ADA deficiency, the authors synthesized cDNAs to ADA mRNAs from two cell lines, GM2756 and GM2825A, derived from ADA-deficient immunodeficient patients. Sequence analysis of GM2756 cDNA clones revealed a different point mutation in each allele that causes amino acid changes of alanine to valine and arginine to histidine. One allele of GM2825A also has a point mutation that causes an alanine to valine substitution. The other allele of GM2825A was found to produce an mRNA in which exon 4 had been spliced out but had no other detrimental mutations. S1 nuclease mapping of GM2825A mRNA showed equal abundance of the full-length ADA mRNA and the ADA mRNA that was missing exon 4. Several of the ADA cDNA clones extended 5' of the major initiation start site, indicating multiple start sites for ADA transcription. The point mutations in GM2756 and GM2825A and the absence of exon 4 in GM2825A appear to be directly responsible for the ADA deficiency. Comparison of a number of normal and mutant ADA cDNA sequences showed a number of changes in the third base of codons. These change do not affect the amino acid sequence. Analyses of ADA cDNAs from different cell lines detected aberrant RNA species that either included intron 7 or excluded exon 7. Their presence is a result of aberrant splicing of pre-mRNAs and is not related to mutations that cause ADA deficiency

  3. Adenosine Receptor Stimulation by Polydeoxyribonucleotide Improves Tissue Repair and Symptomology in Experimental Colitis.

    Pallio, Giovanni; Bitto, Alessandra; Pizzino, Gabriele; Galfo, Federica; Irrera, Natasha; Squadrito, Francesco; Squadrito, Giovanni; Pallio, Socrate; Anastasi, Giuseppe P; Cutroneo, Giuseppina; Macrì, Antonio; Altavilla, Domenica

    2016-01-01

    Activation of the adenosine receptor pathway has been demonstrated to be effective in improving tissue remodeling and blunting the inflammatory response. Active colitis is characterized by an intense inflammatory reaction resulting in extensive tissue damage. Symptomatic improvement requires both control of the inflammatory process and repair and remodeling of damaged tissues. We investigated the ability of an A2A receptor agonist, polydeoxyribonucleotide (PDRN), to restore tissue structural integrity in two experimental colitis models using male Sprague-Dawley rats. In the first model, colitis was induced with a single intra-colonic instillation of dinitrobenzenesulfonic acid (DNBS), 25 mg diluted in 0.8 ml 50% ethanol. After 6 h, animals were randomized to receive either PDRN (8 mg/kg/i.p.), or PDRN + the A2A antagonist [3,7-dimethyl-1-propargylxanthine (DMPX); 10 mg/kg/i.p.], or vehicle (0.8 ml saline solution) daily. In the second model, dextran sulfate sodium (DSS) was dissolved in drinking water at a concentration of 8%. Control animals received standard drinking water. After 24 h animals were randomized to receive PDRN or PDRN+DMPX as described above. Rats were sacrificed 7 days after receiving DNBS or 5 days after DSS. In both experimental models of colitis, PDRN ameliorated the clinical symptoms and weight loss associated with disease as well as promoted the histological repair of damaged tissues. Moreover, PDRN reduced expression of inflammatory cytokines, myeloperoxidase activity, and malondialdehyde. All these effects were abolished by the concomitant administration of the A2A antagonist DMPX. Our study suggests that PDRN may represent a promising treatment for improving tissue repair during inflammatory bowel diseases. PMID:27601997

  4. Adenosine-5'-triphosphate release by Mannheimia haemolytica, lipopolysaccharide, and interleukin-1 stimulated bovine pulmonary epithelial cells.

    Craddick, Michael; Patel, Rakhi; Lower, Amanda; Highlander, Sarah; Ackermann, Mark; McClenahan, David

    2012-09-15

    Mannheimia haemolytica, one of the agents associated with bovine respiratory disease complex, can cause severe lung pathology including the leakage of vascular products into the airways and alveoli. Previous work by this laboratory has demonstrated that bovine lung endothelial and epithelial cells undergo dramatic permeability increases when exposed to adenosine-5'-triphosphate (ATP). Therefore, we wanted to determine if ATP levels were elevated in bronchoalveolar lavage (BAL) samples from calves experimentally infected with M. haemolytica. In addition, cultured bovine pulmonary epithelial (BPE) cells were stimulated with heat-killed and live M. haemolytica bacteria, lipopolysaccharide (LPS), lipoteichoic acid (LTA), interleukin-1 (IL-1), and zymosan activated plasma (ZAP) to determine whether they might release extracellular ATP during in vitro infection. Calves experimentally exposed to M. haemolytica had an approximately 2-fold higher level of ATP in their BAL samples compared to control. BPE cells exposed to increasing numbers of heat-killed or live M. haemolytica had significantly increased levels of ATP release as compared to time-matched controls. Finally, BPE cells treated with several concentrations of LPS and IL-1 had increases in ATP release as compared to time-matched controls. This increase appeared to be a result of active ATP secretion by the cells, as cell viability was similar between treated and non-treated cells. Neither ZAP nor LTA induced any ATP release by the cells. In conclusion, ATP levels are elevated in lung secretions from calves infected with M. haemolytica. In addition, lung epithelial cells can actively release ATP when exposed to heat-killed or live M. haemolytica, LPS or IL-1. PMID:22771196

  5. Synthesis and crystal structure study of 2′-Se-adenosine-derivatized DNA

    SALON; Jozef

    2010-01-01

    The selenium derivatization of nucleic acids is a novel and promising strategy for 3D structure determination of nucleic acids.Selenium can serve as an excellent anomalous scattering center to solve the phase problem,which is one of the two major bottlenecks in macromolecule X-ray crystallography.The other major bottleneck is crystallization.It has been demonstrated that the incorporated selenium functionality at the 2′-positions of the nucleosides and nucleotides is stable and does not cause significant structure perturbation.Furthermore,it was observed that the 2′-Se-derivatization could facilitate crystallization of oligonucleotides with fast crystal growth and high diffraction quality.Herein,we describe a convenient synthesis of the 2′-Se-adenosine phosphoramidite,and report the first synthesis and X-ray crystal structure determination of the DNA containing the 2′-Se-A derivatization.The 3D structure of 2′-Se-A-DNA decamer 5′-GTACGCGT(2′-Se-A)C-3′2 was determined at 1.75 ? resolution,the 2′-Se-functionality points to the minor groove,and the Se-modified and native structures are virtually identical.Moreover,we have observed that the 2′-Se-A modification can greatly facilitate the crystal growth with high diffraction quality.In conjunction with the crystallization facilitation by the 2′-Se-U and 2′-Se-T,this novel observation on the 2′-Se-A functionality suggests that the 2′-Se moiety is sole responsible for the crystallization facilitation and the identity of nucleobases does not influence the crystal growth significantly.

  6. Evaluation of adenosine deaminase seric activity in the diagnosis of bovine tuberculosis

    Márcio Roberto Silva

    2006-06-01

    Full Text Available Determination of seric levels of adenosine deaminase (ADA, an enzyme produced by monocytes/macrophages and lymphocytes, has been used in the diagnosis of human tuberculosis (TB. In the present study, ADA seric activity was evaluated comparatively to the comparative tuberculin test in the diagnosis of bovine tuberculosis. Two hundred fifty-six cattle were classified by origin and by the comparative tuberculin test as TB-positive animals (n = 52, from herds where the Mycobacterium bovis had previously been isolated, and TB-negative animals (n = 204, TB-free herds. The mean ADA seric value from the TB-positive group (4.45 ± 2.33 U/L was significantly lower (p = 0.008 than that observed in sera from the TB-negative group (6.12 ± 4.47 U/L. When animals from a herd with clinical cases of enzootic bovine leukosis of TB-negative group were withdrawn from analysis, the mean ADA seric values of TB-negative group (5.12 ± 3.75 U/L was not significantly different anymore from that of the TB-positive group (p = 0.28. There was no agreement in the diagnosis of bovine TB between comparative tuberculin test and determination of ADA seric values, using two different cutoff points, being 6.12 U/L and 15.0 U/L, (kappa = -0.086 and kappa = -0.082, respectively. In conclusion, the determination of ADA seric activity was not a good auxiliary test for bovine TB, because it was not able to distinguish between TB-positive and TB-negative animals.

  7. Structural basis and evolution of redox regulation in plant adenosine-5;#8242;-phosphosulfate kinase

    Ravilious, Geoffrey E.; Nguyen, Amelia; Francois, Julie A.; Jez, Joseph M. (WU)

    2012-05-08

    Adenosine-5'-phosphosulfate (APS) kinase (APSK) catalyzes the phosphorylation of APS to 3'-phospho-APS (PAPS). In Arabidopsis thaliana, APSK is essential for reproductive viability and competes with APS reductase to partition sulfate between the primary and secondary branches of the sulfur assimilatory pathway; however, the biochemical regulation of APSK is poorly understood. The 1.8-{angstrom} resolution crystal structure of APSR from A. thaliana (AtAPSK) in complex with {beta},{gamma}-imidoadenosine-5'-triphosphate, Mg{sup 2+}, and APS provides a view of the Michaelis complex for this enzyme and reveals the presence of an intersubunit disulfide bond between Cys86 and Cys119. Functional analysis of AtAPSK demonstrates that reduction of Cys86-Cys119 resulted in a 17-fold higher kcat/Km and a 15-fold increase in Ki for substrate inhibition by APS compared with the oxidized enzyme. The C86A/C119A mutant was kinetically similar to the reduced WT enzyme. Gel- and activity-based titrations indicate that the midpoint potential of the disulfide in AtAPSK is comparable to that observed in APS reductase. Both cysteines are invariant among the APSK from plants, but not other organisms, which suggests redox-control as a unique regulatory feature of the plant APSK. Based on structural, functional, and sequence analyses, we propose that the redox-sensitive APSK evolved after bifurcation of the sulfur assimilatory pathway in the green plant lineage and that changes in redox environment resulting from oxidative stresses may affect partitioning of APS into the primary and secondary thiol metabolic routes by having opposing effects on APSK and APS reductase in plants.

  8. Hemodynamic significance of coronary stenosis by vessel attenuation measurement on CT compared with adenosine perfusion MRI

    Highlights: • The majority of anatomical coronary stenoses do not cause myocardial ischemia. • cCTA-derived CCO decrease expresses luminal density gradient across stenosis. • CCO decrease differentiates between anatomical stenoses with and without associated myocardial ischemia. • CCO decrease assessment can exclude the majority of stenoses without hemodynamic significance. - Abstract: Purpose: We assessed the association between corrected contrast opacification (CCO) based on coronary computed tomography angiography (cCTA) and inducible ischemia by adenosine perfusion magnetic resonance imaging (APMR). Methods: Sixty cardiac asymptomatic patients with extra-cardiac arterial disease (mean age 64.4 ± 7.7 years; 78% male) underwent cCTA and APMR. Luminal CT attenuation values (Hounsfield Units) were measured in coronary arteries from proximal to distal, with additional measurements across sites with >50% lumen stenosis. CCO was calculated by dividing coronary CT attenuation by descending aorta CT attenuation. A reversible perfusion defect on APMR was considered as myocardial ischemia. Results: In total, 169 coronary stenoses were found. Seven patients had 8 perfusion defects on APMR, with 11 stenoses in corresponding vessels. CCO decrease across stenoses with hemodynamic significance was 0.144 ± 0.112 compared to 0.047 ± 0.104 across stenoses without hemodynamic significance (P = 0.003). CCO decrease in lesions with and without anatomical stenosis was similar (0.054 ± 0.116 versus 0.052 ± 0.101; P = 0.89). Using 0.20 as preliminary CCO decrease cut-off, hemodynamic significance would be excluded in 82.9% of anatomical stenoses. Conclusions: CCO decrease across coronary stenosis is associated with myocardial ischemia on APMR. CCO based on common cCTA data is a novel method to assess hemodynamic significance of anatomical stenosis

  9. Roflumilast combined with adenosine increases mucosal hydration in human airway epithelial cultures after cigarette smoke exposure.

    Tyrrell, Jean; Qian, Xiaozhong; Freire, Jose; Tarran, Robert

    2015-05-15

    Chronic obstructive pulmonary disease (COPD) is a growing cause of morbidity and mortality worldwide. Recent studies have shown that cigarette smoke (CS) induces cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction, which leads to airway-surface liquid (ASL) dehydration. This in turn contributes to the mucus dehydration and impaired mucociliary clearance that are seen in the chronic bronchitis form of COPD. Roflumilast is a phosphodiesterase 4 inhibitor that may improve lung function and reduce the frequency of exacerbations in patients with COPD. Although roflumilast can affect cAMP metabolism, little is known about the downstream pharmacological effects in the airways. We hypothesized that roflumilast would increase ASL rehydration in human bronchial epithelial cultures (HBECs) after chronic CS exposure. cAMP production was measured by Förster resonance energy transfer in HEK293T cells and by ELISA in HBECs. ASL height was measured by xz-confocal microscopy after air exposure or following HBEC exposure to freshly produced CS. Roflumilast had little effect on cAMP or ASL height when applied on its own; however, roflumilast significantly potentiated adenosine-induced increases in cAMP and ASL height in CS-exposed HBECs. Roflumilast increased the rate of ASL height recovery in cultures after CS exposure compared with controls. In contrast, the β2-adrenergic receptor agonists isoproterenol and salmeterol failed to increase ASL height after CS exposure. Our data suggest that roflumilast can increase ASL hydration in CS-exposed HBECs, which is predicted to be beneficial for the treatment of mucus dehydration/mucus stasis in patients with COPD chronic bronchitis. PMID:25795727

  10. Amperometric biosensor system for simultaneous determination of adenosine-5'-triphosphate and glucose.

    Kucherenko, Ivan S; Didukh, Daria Yu; Soldatkin, Oleksandr O; Soldatkin, Alexei P

    2014-06-01

    The majority of biosensors for adenosine-5'-triphosphate (ATP) determination are based on cascades of enzymatic reactions; therefore, they are sensitive to glucose or glycerol (depending on the enzymatic system) as well as to ATP. The presence of unknown concentrations of these substances in the sample greatly complicates the determination of ATP. To overcome this disadvantage of known biosensors, we developed a biosensor system consisting of two biosensors: the first one is based on glucose oxidase and is intended for measuring glucose concentration, and the second one is based on glucose oxidase and hexokinase and is sensitive toward both glucose and ATP. Using glucose concentration measured by the first biosensor, we can analyze the total response to glucose and ATP obtained by the second biosensor. Platinum disc electrodes were used as amperometric transducers. The polyphenilenediamine membrane was deposited onto the surface of platinum electrodes to avoid the response to electroactive substances. The effect of glucose concentration on biosensor determination of ATP was studied. The reproducibility of biosensor responses to glucose and ATP during a day was tested (relative standard deviation, RSD, of responses to glucose was 3-6% and to ATP was 8-12%) as well as storage stability of the biosensors (no decrease of glucose responses and 43% drop of ATP responses during 50 days). The measurements of ATP and glucose in pharmaceutical vials (including mixtures of ATP and glucose) were carried out. It was shown that the developed biosensor system can be used for simultaneous analysis of glucose and ATP concentrations in water solutions. PMID:24810180

  11. Activation of the A2A adenosine G-protein-coupled receptor by conformational selection.

    Ye, Libin; Van Eps, Ned; Zimmer, Marco; Ernst, Oliver P; Prosser, R Scott

    2016-05-12

    Conformational selection and induced fit are two prevailing mechanisms to explain the molecular basis for ligand-based activation of receptors. G-protein-coupled receptors are the largest class of cell surface receptors and are important drug targets. A molecular understanding of their activation mechanism is critical for drug discovery and design. However, direct evidence that addresses how agonist binding leads to the formation of an active receptor state is scarce. Here we use (19)F nuclear magnetic resonance to quantify the conformational landscape occupied by the adenosine A2A receptor (A2AR), a prototypical class A G-protein-coupled receptor. We find an ensemble of four states in equilibrium: (1) two inactive states in millisecond exchange, consistent with a formed (state S1) and a broken (state S2) salt bridge (known as 'ionic lock') between transmembrane helices 3 and 6; and (2) two active states, S3 and S3', as identified by binding of a G-protein-derived peptide. In contrast to a recent study of the β2-adrenergic receptor, the present approach allowed identification of a second active state for A2AR. Addition of inverse agonist (ZM241385) increases the population of the inactive states, while full agonists (UK432097 or NECA) stabilize the active state, S3', in a manner consistent with conformational selection. In contrast, partial agonist (LUF5834) and an allosteric modulator (HMA) exclusively increase the population of the S3 state. Thus, partial agonism is achieved here by conformational selection of a distinct active state which we predict will have compromised coupling to the G protein. Direct observation of the conformational equilibria of ligand-dependent G-protein-coupled receptor and deduction of the underlying mechanisms of receptor activation will have wide-reaching implications for our understanding of the function of G-protein-coupled receptor in health and disease. PMID:27144352

  12. Neuroprotective effects of adenosine isolated from Cordyceps cicadae against oxidative and ER stress damages induced by glutamate in PC12 cells.

    Olatunji, Opeyemi J; Feng, Yan; Olatunji, Oyenike O; Tang, Jian; Ouyang, Zhen; Su, Zhaoliang; Wang, Dujun; Yu, Xiaofeng

    2016-06-01

    Glutamate has been proven to induce oxidative stress through the formation of reactive oxygen species (ROS) and increased calcium overload which results in neuronal injury, development of neurodegenerative diseases and death. Adenosine is one of the bioactive nucleosides found in Cordyceps cicadae and it has displayed several pharmacological activities including neuroprotection. In this study, the protective effects of adenosine from C. cicadae against glutamate-induce oxidative stress in PC12 cells were evaluated. The exposure of PC12 cells to glutamate (5mM) induced the formation of ROS, increased Ca(2+) influx, endoplasmic reticulum (ER) stress and up regulated the expression of pro-apoptotic factor Bax. However, pretreatment with adenosine markedly increased cell viability, decreased the elevated levels of ROS and Ca(2+) induced by glutamate. Furthermore adenosine increased the activities of GSH-Px and SOD, as well as retained mitochondria membrane potential (MMP), increased Bcl-2/Bax ratio, and reduced the expression of ERK, p38, and JNK. Overall, our results suggest that adenosine may be a promising potential therapeutic agent for the prevention and treatment of neurodegenerative disorders. PMID:27114365

  13. Radioactive human cDNA microarray: comparison of anti-cancer effect between 8-chloro-cAMP and 8-chloro-adenosine

    Eight-chloroadenosine 3.5-monophosphate (8-Cl-cAMP), a site-selective cyclic adenosine 3,5-monophosphate (cAMP) analogue, exhibits growth inhibition in a broad spectrum of cancer cell lines. Nonetheless, there has been a debate as to whether it is a prodrug for its 8-Cl-adenosine metabolite. Using human cDNA microarray, we investigated a pattern of gene regulation under the treatment of 8-Cl-cAMP and 8-Cl-adenosine in PC3M (ATCC CRL-1435; human prostate cancer cell line). The general methodology of arraying is based on the procedures of DeRisi, et al. (Nature Genetics 14: 48, 1996). The gene expression in PC3M by treating 8-Cl-cAMP 8-Cl-adenosine demonstrated a different pattern compared with nontreated control: bifurcated types for up-regulation but a single-directed type for down-regulation. In summary, we demonstrated that the human cDNA microarray is highly likely to be an efficient technology for evaluating the gene regulation of anti-cancer therapeutic agents, such as 8-Cl-cAMP vs. 8-Cl-adenosine, which has been controverted for a long time

  14. Perinatal caffeine, acting on maternal adenosine A(1 receptors, causes long-lasting behavioral changes in mouse offspring.

    Olga Björklund

    Full Text Available BACKGROUND: There are lingering concerns about caffeine consumption during pregnancy or the early postnatal period, partly because there may be long-lasting behavioral changes after caffeine exposure early in life. METHODOLOGY/PRINCIPAL FINDINGS: We show that pregnant wild type (WT mice given modest doses of caffeine (0.3 g/l in drinking water gave birth to offspring that as adults exhibited increased locomotor activity in an open field. The offspring also responded to cocaine challenge with greater locomotor activity than mice not perinatally exposed to caffeine. We performed the same behavioral experiments on mice heterozygous for adenosine A(1 receptor gene (A(1RHz. In these mice signaling via adenosine A(1 receptors is reduced to about the same degree as after modest consumption of caffeine. A(1RHz mice had a behavioral profile similar to WT mice perinatally exposed to caffeine. Furthermore, it appeared that the mother's genotype, not offspring's, was critical for behavioral changes in adult offspring. Thus, if the mother partially lacked A(1 receptors the offspring displayed more hyperactivity and responded more strongly to cocaine stimulation as adults than did mice of a WT mother, regardless of their genotype. This indicates that long-term behavioral alterations in the offspring result from the maternal effect of caffeine, and not a direct effect on fetus. WT offspring from WT mother but having a A(1R Hz grandmother preserved higher locomotor response to cocaine. CONCLUSIONS/SIGNIFICANCE: We suggest that perinatal caffeine, by acting on adenosine A(1 receptors in the mother, causes long-lasting behavioral changes in the offspring that even manifest themselves in the second generation.

  15. Role of Adenosine Receptor(s) in the Control of Vascular Tone in the Mouse Pudendal Artery.

    Labazi, Hicham; Tilley, Stephen L; Ledent, Catherine; Mustafa, S Jamal

    2016-03-01

    Activation of adenosine receptors (ARs) has been implicated in the modulation of renal and cardiovascular systems, as well as erectile functions. Recent studies suggest that adenosine-mediated regulation of erectile function is mainly mediated through A2BAR activation. However, no studies have been conducted to determine the contribution of AR subtype in the regulation of the vascular tone of the pudendal artery (PA), the major artery supplying and controlling blood flow to the penis. Our aim was to characterize the contribution of AR subtypes and identify signaling mechanisms involved in adenosine-mediated vascular tone regulation in the PA. We used a DMT wire myograph for muscle tension measurements in isolated PAs from wild-type, A2AAR knockout, A2BAR knockout, and A2A/A2BAR double-knockout mice. Real-time reverse transcription-polymerase chain reaction was used to determine the expression of the AR subtypes. Data from our pharmacologic and genetic approaches suggest that AR activation-mediated vasodilation in the PA is mediated by both the A2AAR and A2BAR, whereas neither the A1AR nor A3AR play a role in vascular tone regulation of the PA. In addition, we showed that A2AAR- and A2BAR-mediated vasorelaxation requires activation of nitric oxide and potassium channels; however, only the A2AAR-mediated response requires protein kinase A activation. Our data are complemented by mRNA expression showing the expression of all AR subtypes with the exception of the A3AR. AR signaling in the PA may play an important role in mediating erection and represent a promising therapeutic option for the treatment of erectile dysfunction. PMID:26718241

  16. Peripheral Adenosine A3 Receptor Activation Causes Regulated Hypothermia in Mice That Is Dependent on Central Histamine H1 Receptors.

    Carlin, Jesse Lea; Tosh, Dilip K; Xiao, Cuiying; Piñol, Ramón A; Chen, Zhoumou; Salvemini, Daniela; Gavrilova, Oksana; Jacobson, Kenneth A; Reitman, Marc L

    2016-02-01

    Adenosine can induce hypothermia, as previously demonstrated for adenosine A1 receptor (A1AR) agonists. Here we use the potent, specific A3AR agonists MRS5698, MRS5841, and MRS5980 to show that adenosine also induces hypothermia via the A3AR. The hypothermic effect of A3AR agonists is independent of A1AR activation, as the effect was fully intact in mice lacking A1AR but abolished in mice lacking A3AR. A3AR agonist-induced hypothermia was attenuated by mast cell granule depletion, demonstrating that the A3AR hypothermia is mediated, at least in part, via mast cells. Central agonist dosing had no clear hypothermic effect, whereas peripheral dosing of a non-brain-penetrant agonist caused hypothermia, suggesting that peripheral A3AR-expressing cells drive the hypothermia. Mast cells release histamine, and blocking central histamine H1 (but not H2 or H4) receptors prevented the hypothermia. The hypothermia was preceded by hypometabolism and mice with hypothermia preferred a cooler environmental temperature, demonstrating that the hypothermic state is a coordinated physiologic response with a reduced body temperature set point. Importantly, hypothermia is not required for the analgesic effects of A3AR agonists, which occur with lower agonist doses. These results support a mechanistic model for hypothermia in which A3AR agonists act on peripheral mast cells, causing histamine release, which stimulates central histamine H1 receptors to induce hypothermia. This mechanism suggests that A3AR agonists will probably not be useful for clinical induction of hypothermia. PMID:26606937

  17. The effects of nucleus accumbens μ-opioid and adenosine 2A receptor stimulation and blockade on instrumental learning.

    Clissold, Kara A; Pratt, Wayne E

    2014-11-01

    Prior research has shown that glutamate and dopamine receptors in the nucleus accumbens (NAcc) core are critical for the learning of an instrumental response for food reinforcement. It has also been demonstrated that μ-opioid and adenosine A2A receptors within the NAcc impact feeding and motivational processes. In these experiments, we examined the potential roles of NAcc μ-opioid and A2A receptors on instrumental learning and performance. Sprague-Dawley rats were food restricted and trained to lever press following daily intra-accumbens injections of the A2A receptor agonist CGS 21680 (at 0.0, 6.0, or 24.0ng/side), the A2A antagonist pro-drug MSX-3 (at 0.0, 1.0, or 3.0μg/side), the μ-opioid agonist DAMGO (at 0.0, 0.025, or 0.025μg/side), or the opioid receptor antagonist naltrexone (at 0.0, 2.0 or 20.0μg/side). After five days, rats continued training without drug injections until lever pressing rates stabilized, and were then tested with a final drug test to assess potential performance effects. Stimulation, but not inhibition, of NAcc adenosine A2A receptors depressed lever pressing during learning and performance tests, but did not impact lever pressing on non-drug days. Both μ-opioid receptor stimulation and blockade inhibited learning of the lever-press response, though only naltrexone treatment caused impairments in lever-pressing after the task had been learned. The effect of A2A receptor stimulation on learning and performance were consistent with known effects of adenosine on effort-related processes, whereas the pattern of lever presses, magazine approaches, and pellet consumption following opioid receptor manipulations suggested that their effects may have been driven by drug-induced shifts in the incentive value of the sugar reinforcer. PMID:25101542

  18. Molecular structure of tetraaqua adenosine 5'-triphosphate aluminium(III) complex: A study involving Raman spectroscopy, theoretical DFT and potentiometry

    Tenório, Thaís; Silva, Andréa M.; Ramos, Joanna Maria; Buarque, Camilla D.; Felcman, Judith

    2013-03-01

    The Alzheimer's disease is one of the most common neurodegenerative diseases that affect elderly population, due to the formation of β-amyloid protein aggregate and several symptoms, especially progressive cognitive decline. The result is a decrease in capture of glucose by cells leading to obliteration, meddling in the Krebs cycle, the principal biochemical route to the energy production leading to a decline in the levels of adenosine 5'-triphosphate. Aluminium(III) is connected to Alzheimer's and its ion provides raise fluidity of the plasma membrane, decrease cell viability and aggregation of amyloid plaques. Studies reveal that AlATP complex promotes the formation of reactive fibrils of β-amyloid protein and independent amyloidogenic peptides, suggesting the action of the complex as a chaperone in the role pathogenic process. In this research, one of complexes formed by Al(III) and adenosine 5'-triphosphate in aqueous solution is analyzed by potentiometry, Raman spectroscopy and ab initio calculations. The value of the log KAlATP found was 9.21 ± 0.01 and adenosine 5'-triphosphate should act as a bidentate ligand in the complex. Raman spectroscopy and potentiometry indicate that donor atoms are the oxygen of the phosphate β and the oxygen of the phosphate γ, the terminal phosphates. Computational calculations using Density Functional Theory, with hybrid functions B3LYP and 6-311++G(d,p) basis set regarding water solvent effects, have confirmed the results. Frontier molecular orbitals, electrostatic potential contour surface, electrostatic potential mapped and Mulliken charges of the title molecule were also investigated.

  19. Nucleoside-derived antagonists to A3 adenosine receptors lower mouse intraocular pressure and act across species.

    Wang, Zhao; Do, Chi Wai; Avila, Marcel Y; Peterson-Yantorno, Kim; Stone, Richard A; Gao, Zhan-Guo; Joshi, Bhalchandra; Besada, Pedro; Jeong, Lak Shin; Jacobson, Kenneth A; Civan, Mortimer M

    2010-01-01

    The purpose of the study was to determine whether novel, selective antagonists of human A3 adenosine receptors (ARs) derived from the A3-selective agonist Cl-IB-MECA lower intraocular pressure (IOP) and act across species. IOP was measured invasively with a micropipette by the Servo-Null Micropipette System (SNMS) and by non-invasive pneumotonometry during topical drug application. Antagonist efficacy was also assayed by measuring inhibition of adenosine-triggered shrinkage of native bovine nonpigmented ciliary epithelial (NPE) cells. Five agonist-based A3AR antagonists lowered mouse IOP measured with SNMS tonometry by 3-5 mm Hg within minutes of topical application. Of the five agonist derivatives, LJ 1251 was the only antagonist to lower IOP measured by pneumotonometry. No effect was detected pneumotonometrically over 30 min following application of the other four compounds, consonant with slower, smaller responses previously measured non-invasively following topical application of A3AR agonists and the dihydropyridine A3AR antagonist MRS 1191. Latanoprost similarly lowered SNMS-measured IOP, but not IOP measured non-invasively over 30 min. Like MRS 1191, agonist-based A3AR antagonists applied to native bovine NPE cells inhibited adenosine-triggered shrinkage. In summary, the results indicate that antagonists of human A3ARs derived from the potent, selective A3 agonist Cl-IB-MECA display efficacy in mouse and bovine cells, as well. When intraocular delivery was enhanced by measuring mouse IOP invasively, five derivatives of the A3AR agonist Cl-IB-MECA lowered IOP but only one rapidly reduced IOP measured non-invasively after topical application. We conclude that derivatives of the highly-selective A3AR agonist Cl-IB-MECA can reduce IOP upon reaching their intraocular target, and that nucleoside-based derivatives are promising A3 antagonists for study in multiple animal models. PMID:19878673

  20. The Role of cGMP on Adenosine A1 Receptor-mediated Inhibition of Synaptic Transmission at the Hippocampus

    Pinto, Isa; Serpa, André; Sebastião, Ana M.; Cascalheira, José F.

    2016-01-01

    Both adenosine A1 receptor and cGMP inhibit synaptic transmission at the hippocampus and recently it was found that A1 receptor increased cGMP levels in hippocampus, but the role of cGMP on A1 receptor-mediated inhibition of synaptic transmission remains to be established. In the present work we investigated if blocking the NOS/sGC/cGMP/PKG pathway using nitric oxide synthase (NOS), protein kinase G (PKG), and soluble guanylyl cyclase (sGC) inhibitors modify the A1 receptor effect on synaptic transmission. Neurotransmission was evaluated by measuring the slope of field excitatory postsynaptic potentials (fEPSPs) evoked by electrical stimulation at hippocampal slices. N6-cyclopentyladenosine (CPA, 15 nM), a selective A1 receptor agonist, reversibly decreased the fEPSPs by 54 ± 5%. Incubation of the slices with an inhibitor of NOS (L-NAME, 200 μM) decreased the CPA effect on fEPSPs by 57 ± 9% in female rats. In males, ODQ (10 μM), an sGC inhibitor, decreased the CPA inhibitory effect on fEPSPs by 23 ± 6%, but only when adenosine deaminase (ADA,1 U/ml) was present; similar results were found in females, where ODQ decreased CPA-induced inhibition of fEPSP slope by 23 ± 7%. In male rats, the presence of the PKG inhibitor (KT5823, 1 nM) decreased the CPA effect by 45.0 ± 9%; similar results were obtained in females, where KT5823 caused a 32 ± 9% decrease on the CPA effect. In conclusion, the results suggest that the inhibitory action of adenosine A1 receptors on synaptic transmission at hippocampus is, in part, mediated by the NOS/sGC/cGMP/PKG pathway.

  1. Adenosine A1 receptors in human sleep regulation studied by electroencephalography (EEG) and positron emission tomography (PET)

    Sleep is an essential physiological process. However, the functions of sleep and the endogenous mechanisms involved in sleep regulation are only partially understood. Convergent lines of evidence support the hypothesis that the build-up of sleep propensity during wakefulness and its decline during sleep are associated with alterations in brain adenosine levels and adenosine receptor concentrations. The non-selective A1 and A2A adenosine receptor antagonist caffeine stimulates alertness and is known to attenuate changes in the waking and sleep electroencephalogram (EEG) typically observed after prolonged waking. Several findings point to an important function of the adenosine A1 receptor (A1AR) in the modulation of vigilance states. The A1AR is densely expressed in brain regions involved in sleep regulation, and pharmacological manipulations affecting the A1AR were shown to influence sleep propensity and sleep depth. However, an involvement of the A2A adenosine receptor (A2AAR) is also assumed. The distinct functions of the A1 and A2A receptor subtypes in sleep-wake regulation and in mediating the effects of caffeine have not been identified so far. The selective adenosine A1 receptor antagonist, 8-cyclopentyl-3-(3-18Ffluoropropyl)- 1-propylxanthine (18F-CPFPX), offers the opportunity to get further insights into adenosinergic mechanisms by in vivo imaging of the A1AR subtype with positron emission tomography (PET). The aim of this thesis was to elucidate the role of adenosine A1 receptors in human sleep regulation, combining 18F-CPFPX PET brain imaging and EEG recordings, the gold standard in sleep research. It was hypothesized that sleep deprivation would induce adenosine accumulation and/or changes in A1AR density. Thus, the question was addressed whether these effects of prolonged wakefulness can be visualized by altered 18F-CPFPX binding. Moreover, it was investigated whether radioligand uptake might be influenced by caffeine, since caffeine is known to bind to

  2. Utilization of adenosine triphosphate in rat mast cells during histamine release induced by the ionophore A23187

    Johansen, Torben

    1979-01-01

    The role of endogenous adenosine triphosphate (ATP) in histamine release from rat mast cells induced by the ionophore A23187 in vitro has been studied. 2 The amount of histamine released by calcium from rat mast cells primed with the ionophore A23187 was dependent on the ATP content of the mast...... The observations are consistent with the view that energy requiring processes are involved in ionophore-induced histamine release from rat mast cells although part of the ATP reduction in the aerobic experiments may be due to an uncoupling effect of calcium on the oxidative phosphorylation....

  3. Structural Basis for Inhibition of Mycobacterial and Human Adenosine Kinase by 7-Substituted 7-(Het)aryl-7-deazaadenine Ribonucleosides

    Snášel, Jan; Nauš, Petr; Dostál, Jiří; Hnízda, Aleš; Fanfrlík, Jindřich; Brynda, Jiří; Bourderioux, Aurelie; Dušek, Michal; Dvořáková, H.; Stolaříková, J.; Zábranská, Helena; Pohl, Radek; Konečný, P.; Džubák, P.; Votruba, Ivan; Hajdúch, M.; Řezáčová, Pavlína; Veverka, Václav; Hocek, Michal; Pichová, Iva

    2014-01-01

    Roč. 57, č. 20 (2014), s. 8268-8279. ISSN 0022-2623 R&D Projects: GA ČR GAP207/11/0344; GA MŠk LO1302; GA MŠk(CZ) LK11205 EU Projects: European Commission(XE) 241587 - SYSTEMTB Grant ostatní: GA MŠk(CZ) LM2011020 Institutional support: RVO:61388963 ; RVO:68378271 Keywords : 7-(het)aryl-7-deazaadenine ribonucleosides * enzyme inhibition * adenosine kinase * cytostatic activity Subject RIV: CC - Organic Chemistry Impact factor: 5.447, year: 2014

  4. A new method that investigates superoxide versus respiration in vitro using bioluminescence and Sepharose-bound adenosine derivatives

    Lippman, R.D.

    1982-06-01

    In vitro reactions between superoxide and phosphate derivatives of adenosine yielded quantitative amounts of stable ozonide-products. ADP-ozonide was formed in an optimized in vitro synthesis from ADP + O-(2) and affected by inhibitors and uncouplers in a similar manner to in vivo, oxidative-phosphorylation results. ADP-ozonide was further reacted with phosphoric acid to form ATP. Superoxide and ADP-ozonide may be important carrier-intermediates between respiration's electron-transport chain and nodule ATP formation in vivo.

  5. Role of adenosine A2A receptor signaling in the nicotine-evoked attenuation of reflex cardiac sympathetic control

    Baroreflex dysfunction contributes to increased cardiovascular risk in cigarette smokers. Given the importance of adenosinergic pathways in baroreflex control, the hypothesis was tested that defective central adenosinergic modulation of cardiac autonomic activity mediates the nicotine-baroreflex interaction. Baroreflex curves relating changes in heart rate (HR) to increases or decreases in blood pressure (BP) evoked by i.v. doses (1-16 μg/kg) of phenylephrine (PE) and sodium nitroprusside (SNP), respectively, were constructed in conscious rats; slopes of the curves were taken as measures of baroreflex sensitivity (BRS). Nicotine (25 and 100 μg/kg i.v.) dose-dependently reduced BRSSNP in contrast to no effect on BRSPE. BRSSNP was also attenuated after intracisternal (i.c.) administration of nicotine. Similar reductions in BRSSNP were observed in rats pretreated with atropine or propranolol. The combined treatment with nicotine and atropine produced additive inhibitory effects on BRS, an effect that was not demonstrated upon concurrent exposure to nicotine and propranolol. BRSSNP was reduced in preparations treated with i.c. 8-phenyltheophylline (8-PT, nonselective adenosine receptor antagonist), 8-(3-Chlorostyryl) caffeine (CSC, A2A antagonist), or VUF5574 (A3 antagonist). In contrast, BRSSNP was preserved after blockade of A1 (DPCPX) or A2B (alloxazine) receptors or inhibition of adenosine uptake by dipyridamole. CSC or 8-PT abrogated the BRSSNP depressant effect of nicotine whereas other adenosinergic antagonists were without effect. Together, nicotine preferentially impairs reflex tachycardia via disruption of adenosine A2A receptor-mediated facilitation of reflex cardiac sympathoexcitation. Clinically, the attenuation by nicotine of compensatory sympathoexcitation may be detrimental in conditions such as hypothalamic defense response, posture changes, and ventricular rhythms. - Research highlights: → The role of central adenosinergic sites in the nicotine

  6. Non-selective and selective adenosine receptor agonists in the treatment of radiation- and chemotherapy-induced myelosuppression

    Hofer, Michal; Pospíšil, Milan

    Nurnberg, 2008. A-127. [EHRLICH II - 2nd World Conference on Magic Bullets, Celebrating the 100th Anniversary of the Nobel Prize Award to Paul Ehrlich. 03.10.2008-05.10.2008, Nurnberg] R&D Projects: GA ČR(CZ) GA305/06/0015; GA ČR(CZ) GA305/08/0158 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : adenosine receptor agonists * hematopoiesis * treatment of myelosuppression Subject RIV: BO - Biophysics

  7. Adenosine triphosphate levels during anaphylactic histamine release in rat mast cells in vitro. Effects of glycolytic and respiratory inhibitors

    Johansen, Torben

    1979-01-01

    The adenosine triphosphate (ATP) content of rat mast cells was studied during and after anaphylactic histamine release. The almost identical time course of ATP decrease from mast cells treated with either glycolytic or respiratory inhibitors supports the view that the ATP depletion was largely...... related to the histamine release process and not to an uncoupling of oxidative phosphorylation by an increased concentration of cytosol Ca2+. The ATP content of the cells was not restored within the 2 h of observation. No inhibition of lactate production from mast cells exposed to antigen in the presence...

  8. Evaluation of contrast wash-in and peak enhancement in adenosine first pass perfusion CMR in patients post bypass surgery

    Schnackenburg Bernhard

    2010-05-01

    Full Text Available Abstract Background Adenosine first pass perfusion cardiovascular magnetic resonance (CMR yields excellent results for the detection of significant coronary artery disease (CAD. In patients with coronary artery bypass grafts (CABG the kinetics of a contrast bolus may by altered only due to different distances through the bypass grafts compared to native vessels, thereby possibly imitating a perfusion defect. The aim of the study was to evaluate semiquantitative perfusion parameters in order to assess possible differences in epicardial contrast kinetics in areas supplied by native coronaries and CABG, both without significant stenosis. Methods Twenty patients with invasive exclusion of significant CAD (control group and 38 patients with CABG without angiographically significant (≥50% stenosis in unbypassed coronaries or grafts were retrospectively included in the study. They underwent adenosine first pass (0.05 mmol/kg Gd-DTPA perfusion (3 short axis views/heart beat and late gadolinium enhancement (LGE imaging 1 day before invasive coronary angiography. Areas perfused by native coronaries and/or the different bypasses were identified in X-ray angiography using the 16 segment model. In each of these areas upslope and maximal signal intensity (SImax relative to the left ventricular parameters, time to 50% maximal signal intensity (TSI50%max and time to maximal signal intensity (TSImax were calculated. Results In areas perfused by coronary arteries with bypasses compared to native coronaries relative upslope and relative SImax did not show a significant difference. TSI50%max and TSImax in native coronaries and bypasses were 7.2s ± 1.9s vs. 7.5s ± 1.9s (p max resulted in a significant (p Conclusion Adenosine perfusion CMR in patients post CABG may be associated with a short delay in contrast arrival. However, once the contrast is in the myocardium there is similar wash-in kinetics and peak enhancement. Therefore, since the delay is only short

  9. Autoradiographic visualization of A 1-adenosine receptors in brain and peripheral tissues of rat and guinea pig using 125I-HPIA

    A 1-adenosine receptors were identified in sections of rat brain and guinea pig kidney with the radioiodinated agonist 125I-N6-p-hydroxyphenylisopropyladenosine (125I-HPIA) using in vitro autoradiography. The affinities of adenosine receptor ligands in competing with 125I-HPIA binding to tissue sections were in good agreement with those found in membranes and indicate that the binding site represents an A 1 pattern of [3H]N6-cyclohexyladenosine ([3H]CHA) binding sites determined previously, with highest densities in the hippocampus and dentate gyrus, the cerebellar cortex, some thalamic nuclei and certain layers of the cerebral cortex. In the guinea pig kidney 125I-HPIA labelled longitudinal structures in the medulla. This study demonstrates that 125I-HPIA allows the autoradiographic detection of A-1 adenosine receptors in the brain and peripheral organs and has the advantage of short exposure times (author)

  10. β-Nicotinamide adenine dinucleotide acts at prejunctional adenosine A1 receptors to suppress inhibitory musculomotor neurotransmission in guinea pig colon and human jejunum.

    Wang, Guo-Du; Wang, Xi-Yu; Liu, Sumei; Xia, Yun; Zou, Fei; Qu, Meihua; Needleman, Bradley J; Mikami, Dean J; Wood, Jackie D

    2015-06-01

    Intracellular microelectrodes were used to record neurogenic inhibitory junction potentials in the intestinal circular muscle coat. Electrical field stimulation was used to stimulate intramural neurons and evoke contraction of the smooth musculature. Exposure to β-nicotinamide adenine dinucleotide (β-NAD) did not alter smooth muscle membrane potential in guinea pig colon or human jejunum. ATP, ADP, β-NAD, and adenosine, as well as the purinergic P2Y1 receptor antagonists MRS 2179 and MRS 2500 and the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine, each suppressed inhibitory junction potentials in guinea pig and human preparations. β-NAD suppressed contractile force of twitch-like contractions evoked by electrical field stimulation in guinea pig and human preparations. P2Y1 receptor antagonists did not reverse this action. Stimulation of adenosine A1 receptors with 2-chloro-N6-cyclopentyladenosine suppressed the force of twitch contractions evoked by electrical field stimulation in like manner to the action of β-NAD. Blockade of adenosine A1 receptors with 8-cyclopentyl-1,3-dipropylxanthine suppressed the inhibitory action of β-NAD on the force of electrically evoked contractions. The results do not support an inhibitory neurotransmitter role for β-NAD at intestinal neuromuscular junctions. The data suggest that β-NAD is a ligand for the adenosine A1 receptor subtype expressed by neurons in the enteric nervous system. The influence of β-NAD on intestinal motility emerges from adenosine A1 receptor-mediated suppression of neurotransmitter release at inhibitory neuromuscular junctions. PMID:25813057

  11. Differential Expression of Adenosine P1 Receptor ADORA1 and ADORA2A Associated with Glioma Development and Tumor-Associated Epilepsy.

    Huang, Jun; Chen, Ming-Na; Du, Juan; Liu, Hao; He, Yu-Jiao; Li, Guo-Liang; Li, Shu-Yu; Liu, Wei-Ping; Long, Xiao-Yan

    2016-07-01

    Level of adenosine, an endogenous astrocyte-based neuromodulator, is primarily regulated by adenosine P1 receptors. This study assessed expression of adenosine P1 receptors, ADORA1 (adenosine A1 receptor) and ADORA2A (adenosine A2a receptor) and their association with glioma development and epilepsy in glioma patients. Expression of ADORA1/ADORA2A was assessed immunohistochemically in 65 surgically removed glioma tissue and 21 peri-tumor tissues and 8 cases of normal brain tissues obtained from hematoma patients with cerebral trauma. Immunofluorescence, Western blot, and qRT-PCR were also used to verify immunohistochemical data. Adenosine P1 receptor ADORA1 and ADORA2A proteins were localized in the cell membrane and cytoplasm and ADORA1/ADORA2A immunoreactivity was significantly stronger in glioma and peri-tumor tissues that contained infiltrating tumor cells than in normal brain tissues (p < 0.05). The World Health Organization (WHO) grade III gliomas expressed even higher level of ADORA1 and ADORA2A. Western blot and qRT-PCR confirmed immunohistochemical data. Moreover, higher levels of ADORA1 and ADORA2A expression occurred in high-grade gliomas, in which incidence of epilepsy were lower (p < 0.05). In contrast, a lower level of ADORA1/ADORA2A expression was found in peri-tumor tissues with tumor cell presence from patients with epilepsy compared to patients without epilepsy (p < 0.05). The data from the current study indicates that dysregulation in ADORA1/ADORA2A expression was associated with glioma development, whereas low level of ADORA1/ADORA2A expression could increase susceptibility of tumor-associated epilepsy. PMID:27038930

  12. Relationship Between Adenosine - Induced ST Segment Depression During 99mTc-MIBI Scintigraphy and The Severity of Coronary Artery Disease

    Pharmacologic coronary vasodilation in conjunction with myocardial perfusion scintigraphy has become an alternative to dynamic exercise test for the diagnosis and risk stratification of coronary artery disease, especially in patients who are unable to perform adequate exercise. Dipyridamole and adenosine have been used for pharmacologic stress testing with myocardial perfusion imaging. Adenosine is a potent, coronary vasodilator with rapid onset of action, short half life, near maximal coronary vasodilation and less serious side effects. ST segment depression has been reported in about 7-15% of patients with coronary artery disease receiving dipyridamole in conjunction with myocardial perfusion imaging. The exact cause and clinical significance are not known. In order to evaluate the relationship between adenosine-induced ST segment depression during 99mTc-MIBI myocardial perfusion scintigraphy and the severity of coronary artery disease, we performed 99m-MIBI imaging after intravenous infusion of adenosine in 120 patients with suspected coronary artery disease. Of the 120 patients, 28 also performed coronary angiography. There were 24 patients with ST segment depression during 99mTc-MIIBI scintigraphy and 96 patients without ST segment depression. Adenosine was infused intravenously at a dose of 0.14 mg/kg per minute for 6 minutes and 99MmTc-MIB1 was injected at 3 minute. We then compared the hemodynamic changes, side effects, scintigraphic and angiographic findings. Heart rate increased 90 ± 19 beats/minute in the group with ST depression compared with 80 ±16 beats/minute in the group without ST depression(p9mTc-MIBI images were abnormal in 23(96%) patients with ST segment depression and 66(69%) patients without ST segment depression(p99mTc-MIBI myocardial perfusion scintigraphy with intravenous adenosine is related to the severity of coronary artery disease.

  13. A1 adenosine receptor-induced phosphorylation and modulation of transglutaminase 2 activity in H9c2 cells: A role in cell survival.

    Vyas, Falguni S; Hargreaves, Alan J; Bonner, Philip L R; Boocock, David J; Coveney, Clare; Dickenson, John M

    2016-05-01

    The regulation of tissue transglutaminase (TG2) activity by the GPCR family is poorly understood. In this study, we investigated the modulation of TG2 activity by the A1 adenosine receptor in cardiomyocyte-like H9c2 cells. H9c2 cells were lysed following stimulation with the A1 adenosine receptor agonist N(6)-cyclopentyladenosine (CPA). Transglutaminase activity was determined using an amine incorporating and a protein cross linking assay. TG2 phosphorylation was assessed via immunoprecipitation and Western blotting. The role of TG2 in A1 adenosine receptor-induced cytoprotection was investigated by monitoring hypoxia-induced cell death. CPA induced time and concentration-dependent increases in amine incorporating and protein crosslinking activity of TG2. CPA-induced increases in TG2 activity were attenuated by the TG2 inhibitors Z-DON and R283. Responses to CPA were blocked by PKC (Ro 31-8220), MEK1/2 (PD 98059), p38 MAPK (SB 203580) and JNK1/2 (SP 600125) inhibitors and by removal of extracellular Ca(2+). CPA triggered robust increases in the levels of TG2-associated phosphoserine and phosphothreonine, which were attenuated by PKC, MEK1/2 and JNK1/2 inhibitors. Fluorescence microscopy revealed TG2-mediated biotin-X-cadaverine incorporation into proteins and proteomic analysis identified known (Histone H4) and novel (Hexokinase 1) protein substrates for TG2. CPA pre-treatment reversed hypoxia-induced LDH release and decreases in MTT reduction. TG2 inhibitors R283 and Z-DON attenuated A1 adenosine receptor-induced cytoprotection. TG2 activity was stimulated by the A1 adenosine receptor in H9c2 cells via a multi protein kinase dependent pathway. These results suggest a role for TG2 in A1 adenosine receptor-induced cytoprotection. PMID:27005940

  14. Adenosine regulates a chloride channel via protein kinase C and a G protein in a rabbit cortical collecting duct cell line.

    Schwiebert, E. M.; Karlson, K H; Friedman, P A; Dietl, P.; Spielman, W S; Stanton, B.A.

    1992-01-01

    We examined the regulation by adenosine of a 305-pS chloride (Cl-) channel in the apical membrane of a continuous cell line derived from rabbit cortical collecting duct (RCCT-28A) using the patch clamp technique. Stimulation of A1 adenosine receptors by N6-cyclohexyladenosine (CHA) activated the channel in cell-attached patches. Phorbol 12,13-didecanoate and 1-oleoyl 2-acetylglycerol, activators of protein kinase C (PKC), mimicked the effect of CHA, whereas the PKC inhibitor H7 blocked the ac...

  15. Wirkungen einer chronischen Vorbehandlung mit dem selektiven Adenosin-A1-Rezeptor-Agonisten 2-Chloro-N6-Cyclopentyladenosin (CCPA) auf die Nierenfunktion der Ratte

    Maaß, Jannis Justus

    2012-01-01

    Ziel dieser Arbeit war es, die Auswirkungen einer chronischen Behandlung mit einem Adenosin-A1-Rezeptor-Agonisten auf die Nierenfunktion zu untersuchen. Dazu wurde in einer kontrollierten randomisierten Studie Ratten der hochselektive Adenosin-A1-Rezeptor-Agonist 2-Chloro-N6-cyclopentyladenosin (CCPA) sieben Tage lang über das Trinkwasser zugeführt. Die Gabe von CCPA wurde sowohl unter kochsalzreicher- als auch kochsalzarmer Diät durchgeführt. Für die funktionelle Charakterisierung wurde di...

  16. Mice Lacking the Adenosine A1 Receptor Have Normal Spatial Learning and Plasticity in the CA1 Region of the Hippocampus, But They Habituate More Slowly

    Giménez-Llort, Lydia; Masino, Susan A.; Diao, Lihong; Fernández-Teruel, Alberto; Tobeña, Adolf; Halldner-Henriksson, Linda; Fredholm, Bertil B

    2005-01-01

    Using mice with a targeted disruption of the adenosine A1 receptor (A1R), we examined the role of A1Rs in hippocampal long-term potentiation (LTP), long-term depression (LTD), and memory formation. Recordings from the Shaffer collateral–CA1 pathway of hippocampal slices from adult mice showed no differences between theta burst and tetanic stimulation-induced LTP in adenosine A1 receptor knockout (A1R−/−), heterozygote (A1R+/−), and wildtype (A1R+/+) mice. However, paired pulse facilitation wa...

  17. Complex Formation of Adenosine 3',5'-Cyclic Monophosphate with β-Cyclodextrin: Kinetics and Mechanism by Ultrasonic Relaxation

    Adenosine 3',5'-cyclic monophosphate (cAMP) is a second messenger responsible for a multitude of cellular responses. In this study, we utilized β-cyclodextrin (β-CD) as an artificial receptor with a hydrophobic cavity to elucidate the inclusion kinetics of cAMP in a hydrophobic environment using the ultrasonic relaxation method. The results revealed that the interaction of cAMP with β-CD followed a single relaxation curve as a result of host-guest interactions. The inclusion of cAMP into the β-CD cavity was found to be a diffusion-controlled reaction. The dissociation of cAMP from the β-CD cavity was slower than that of adenosine 5'-monophosphate (AMP). The syn and anti glycosyl conformations of adenine nucleotides are considered to play an important role in formation of the inclusion complex. Taken together, our findings indicate that hydrophobic interactions are involved in the inclusion complex formation of cAMP with β-CD and provide insight into the interactions of cAMP with cAMP-binding proteins

  18. Transcriptional activation of the nitrogenase promoter in vitro: adenosine nucleotides are required for inhibition of NIFA activity by NIFL.

    Eydmann, T; Söderbäck, E; Jones, T; Hill, S; Austin, S; Dixon, R

    1995-03-01

    The enhancer-binding protein NIFA is required for transcriptional activation of nif promoters by the alternative holoenzyme form of RNA polymerase, which contains the sigma factor sigma 54 (sigma N). NIFA hydrolyzes nucleoside triphosphates to catalyze the isomerization of closed promoter complexes to transcriptionally competent open complexes. The activity of NIFA is antagonized by the regulatory protein NIFL in response to oxygen and fixed nitrogen in vivo. We have investigated the requirement for nucleotides in the formation and stability of open promoter complexes by NIFA and inhibition of its activity by NIFL at the Klebsiella pneumoniae nifH promoter. Open complexes formed by sigma 54-containing RNA polymerase are considerably more stable to heparin challenge in the presence of GTP than in the presence of ATP. This differential stability is most probably a consequence of GTP being the initiating nucleotide at this promoter. Adenosine nucleosides are specifically required for Azotobacter vinelandii NIFL to inhibit open complex formation by native NIFA, and the nucleoside triphosphatase activity of NIFA is strongly inhibited by NIFL under these conditions. We propose a model in which NIFL modulates the activity of NIFA via an adenosine nucleotide switch. PMID:7868590

  19. Adenosine (ADO) released during orthodromic stimulation of the frog sympathetic ganglion inhibits phosphatidylinositol turnover (PI) associated with synaptic transmission

    The authors have previously demonstrated that 3H-purine release was enhanced during synaptic activation of the prelabelled frog sympathetic ganglion. In addition, during orthodromic stimulation, there is an increased 3H-inositol release (an index of PI) that occurs during the poststimulation period and not during the period of stimulation. They hypothesized that endogenous ADO inhibits PI turnover during orthodromic stimulation. To test this hypothesis (1) they performed experiments to directly measure ADO release in the extracellular fluid by placing the ganglion in a 5 μl drop of Ringer's and let it come to equilibrium with the interstitial fluid, (2) they destroyed endogenous ADO by suffusing adenosine deaminase (ADA) during the stimulation period. Their results show (1) orthodromic stimulation increases release of ADO into the bathing medium, (2) ADA induced an increase of PI during the stimulation period in contrast to an increase seen only during the poststimulation period when ADA was omitted. They conclude that there is dual control of PI during synaptic activity, a stimulatory effect (cause unknown) and a short lived inhibitory effect that is probably caused by adenosine

  20. Exercise-induced increase in interstitial bradykinin and adenosine concentrations in skeletal muscle and peritendinous tissue in humans

    Langberg, H; Bjørn, C; Boushel, Robert Christopher;

    2002-01-01

    been established. Microdialysis (molecular mass cut-off 5 kDa) was performed simultaneously in calf muscle and peritendinous Achilles tissue at rest and during 10 min periods of incremental (0.75 W, 2 W, 3.5 W and 4.75 W) dynamic plantar flexion exercise in 10 healthy individuals (mean age 27 years......Bradykinin is known to cause vasodilatation in resistance vessels and may, together with adenosine, be an important regulator of tissue blood flow during exercise. Whether tissue concentrations of bradykinin change with exercise in skeletal muscle and tendon-related connective tissue has not yet...... interstitial concentration of bradykinin rose in response to exercise both in skeletal muscle (from 23.1 +/- 4.9 nmol l(-1) to 110.5 +/- 37.9 nmol l(-1); P <0.05) and in the peritendinous tissue (from 27.7 +/- 7.8 nmol l(-1) to 105.0 +/- 37.9 nmol l(-1); P <0.05). In parallel, the adenosine concentration...

  1. Adenosine A{sub 1} receptors in contrast media-induced renal dysfunction in the normal rat

    Liss, Per; Palm, Fredrik [Department of Diagnostic Radiology, University Hospital, 75185, Uppsala (Sweden); Department of Medical Cell Biology, University Hospital, 75185, Uppsala (Sweden); Carlsson, Per-Ola [Department of Medical Cell Biology, University Hospital, 75185, Uppsala (Sweden); Department of Medical Sciences, University Hospital, 75185, Uppsala (Sweden); Hansell, Peter [Department of Medical Cell Biology, University Hospital, 75185, Uppsala (Sweden)

    2004-07-01

    Renal vasoconstriction with resultant tissue hypoxia, especially in the renal medulla, has been suggested to play a role in contrast media (CM)-induced nephropathy. In this study we investigated the effects of injection of the non-ionic low-osmolar CM iopromide with and without pretreatment with the selective adenosine A{sub 1}-receptor antagonist DPCPX. The effects were evaluated on regional renal blood flow, outer medullary oxygen tension (PO{sub 2}) and urine output in normal anaesthetised rats. A laser-Doppler technique was used for recording haemodynamic changes while oxygen microelectrodes were used for oxygen measurements. The A{sub 1}-receptor antagonist per se elevated glomerular filtration rate (+44%), cortical blood flow (+15%) and urine output (threefold) while reducing outer medullary PO{sub 2} (-24%). Administration of CM reduced outer medullary blood flow (OMBF; -26%) and PO{sub 2} (-80%) but did not affect cortical blood flow. Urine output increased 28-fold by CM while arterial blood pressure was reduced. The CM-mediated effect on haemodynamics, PO{sub 2}, urine output and blood pressure was unaffected by the A{sub 1}-receptor antagonist. Adenosine A{sub 1}-receptors are not important mediators of the depression of outer medullary blood flow and PO{sub 2} caused by the CM iopromide in the normal rat; however, A{sub 1}-receptors are tonically active to regulate renal haemodynamics, PO{sub 2} and urine production during normal physiological conditions. (orig.)

  2. Crystallization and preliminary X-ray crystallographic analysis of the tRNA-specific adenosine deaminase from Streptococcus pyogenes

    Ku, Min-Je [Functional Proteomics Center, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Won-Ho [Functional Proteomics Center, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Biotechnology and Genetic Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Nam, Ki-hyun; Rhee, Kyeong-hee [Biomedical Research Center, Life Science Division, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Ki-Seog [Biotechnology and Genetic Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Kim, Eunice EunKyung [Biomedical Research Center, Life Science Division, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Yu, Myung-Hee [Functional Proteomics Center, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Hwang, Kwang Yeon, E-mail: hwangky@kist.re.kr [Biomedical Research Center, Life Science Division, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Functional Proteomics Center, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

    2005-04-01

    The tRNA-specific adenosine deaminase from the pathogenic bacteria S. pyogenes has been overexpressed and crystallized. The tRNA-specific adenosine deaminase from the pathogenic bacteria Streptococcus pyogenes (spTAD) has been overexpressed in Escherichia coli and crystallized in the presence of Zn{sup 2+} ion at 295 K using ammonium sulfate as a precipitant. Flash-cooled crystals of spTAD diffracted to 2.0 Å using 30%(v/v) glycerol as a cryoprotectant. X-ray diffraction data have been collected to 2.0 Å using synchrotron radiation. The crystal belongs to the tetragonal space group P4{sub 2}2{sub 1}2, with unit-cell parameters a = b = 81.042, c = 81.270 Å. The asymmetric unit contains one subunit of spTAD, with a corresponding crystal volume per protein weight (V{sub M}) of 3.3 Å{sup 3} Da{sup −1} and a solvent content of 62.7%.

  3. Preclinical studies on [11C]TMSX for mapping adenosine A2A receptors by positron emission tomography

    In previous in vivo studies with mice, rats and monkeys, we have demonstrated that [11C]TMSX ([7-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)- 1,3,7-trimethylxanthine) is a potential radioligand for mapping adenosine A2A receptors of the brain by positron emission tomography (PET). In the present study, we performed a preclinical study. A suitable preparation method for [11C]TMSX injection was established. The radiation absorbed-dose by [11C]TMSX in humans estimated from the tissue distribution in mice was low enough for clinical use, and the acute toxicity and mutagenicity of TMSX were not found. The striatal uptake of [11C]TMSX in mice was reduced by pretreatment with theophylline at the dose of 10 and 100 mg/kg, suggesting that the [11C]TMSX PET should be carefully performed in the patients received with theophylline. We have concluded that [11C]TMSX is suitable for mapping adenosine A2A receptors in the human brain by PET. (author)

  4. A heterodimer of human 3'-phospho-adenosine-5'-phosphosulphate (PAPS) synthases is a new sulphate activating complex

    3'-Phospho-adenosine-5'-phosphosulphate (PAPS) synthases are fundamental to mammalian sulphate metabolism. These enzymes have recently been linked to a rising number of human diseases. Despite many studies, it is not yet understood how the mammalian PAPS synthases 1 and 2 interact with each other. We provide first evidence for heterodimerisation of these two enzymes by pull-down assays and Foerster resonance energy transfer (FRET) measurements. Kinetics of dimer dissociation/association indicates that these heterodimers form as soon as PAPSS1 and -S2 encounter each other in solution. Affinity of the homo- and heterodimers were found to be in the low nanomolar range using anisotropy measurements employing proteins labelled with the fluorescent dye IAEDANS that - in spite of its low quantum yield - is well suited for anisotropy due to its large Stokes shift. Within its kinase domain, the PAPS synthase heterodimer displays similar substrate inhibition by adenosine-5'-phosphosulphate (APS) as the homodimers. Due to divergent catalytic efficacies of PAPSS1 and -S2, the heterodimer might be a way of regulating PAPS synthase function within mammalian cells.

  5. Non-adenosine nucleoside inosine, guanosine and uridine as promising antiepileptic drugs: a summary of current literature.

    Kovacs, Zsolt; Kekesi, Katalin A; Juhasz, Gabor; Barna, Janos; Heja, Laszlo; Lakatos, Renata; Dobolyi, Arpad

    2015-01-01

    Adenosine (Ado) and some non-adenosine (non-Ado) nucleosides including inosine (Ino), guanosine (Guo) and uridine (Urd) are modulatory molecules in the central nervous system (CNS), regulating different physiological and pathophysiological processes in the brain such as sleep and epilepsy. Indeed, different drugs effective on adenosinergic system (e.g., Ado metabolism inhibitors, agonists and antagonists of Ado receptors) are being used in drug development for the treatment of epileptic disorders. Although (i) endogenous Ino, Guo and Urd showed anticonvulsant/antiepileptic effects (e.g., in quinolinic acid - induced seizures and in different epilepsy models such as hippocampal kindling models), and (ii) there is a need to generate new and more effective antiepileptic drugs for the treatment of drug-resistant epilepsies, our knowledge about antiepileptic influence of non-Ado nucleosides is far from complete. Thus, in this review article, we give a short summary of anticonvulsant/antiepileptic effects and mechanisms evoked by Ino, Guo, and Urd. Finally, we discuss some non-Ado nucleoside derivatives and their structures, which may be candidates as potential antiepileptic agents. PMID:25382017

  6. The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Uses its C-Terminus to Regulate the A2B Adenosine Receptor.

    Watson, Michael J; Lee, Shernita L; Marklew, Abigail J; Gilmore, Rodney C; Gentzsch, Martina; Sassano, Maria F; Gray, Michael A; Tarran, Robert

    2016-01-01

    CFTR is an apical membrane anion channel that regulates fluid homeostasis in many organs including the airways, colon, pancreas and sweat glands. In cystic fibrosis, CFTR dysfunction causes significant morbidity/mortality. Whilst CFTR's function as an ion channel has been well described, its ability to regulate other proteins is less understood. We have previously shown that plasma membrane CFTR increases the surface density of the adenosine 2B receptor (A2BR), but not of the β2 adrenergic receptor (β2AR), leading to an enhanced, adenosine-induced cAMP response in the presence of CFTR. In this study, we have found that the C-terminal PDZ-domain of both A2BR and CFTR were crucial for this interaction, and that replacing the C-terminus of A2BR with that of β2AR removed this CFTR-dependency. This observation extended to intact epithelia and disruption of the actin cytoskeleton prevented A2BR-induced but not β2AR-induced airway surface liquid (ASL) secretion. We also found that CFTR expression altered the organization of the actin cytoskeleton and PDZ-binding proteins in both HEK293T cells and in well-differentiated human bronchial epithelia. Furthermore, removal of CFTR's PDZ binding motif (ΔTRL) prevented actin rearrangement, suggesting that CFTR insertion in the plasma membrane results in local reorganization of actin, PDZ binding proteins and certain GPCRs. PMID:27278076

  7. Clinical characteristics in patients showing ischemic electrocardiographic changes during adenosine triphosphate loading single-photon emission computed tomography

    Although ischemic electrocardiographic (ECG) changes during dipyridamole or adenosine infusion have been reported as a marker for severe coronary artery disease (CAD), few studies have focused on ST-segment changes with adenosine triphosphate (ATP)-loading myocardial single-photon emission computed tomography (SPECT). Between January 2003 and August 2008, 4650 consecutive patients underwent ATP-loading SPECT. After 1412 patients with left bundle branch block, pacemaker rhythm, or previous coronary revascularization were excluded, 16 out of 3238 patients (0.5%) showed ischemic ST-segment depression during ATP-loading myocardial SPECT. They were aged 67±11 years; 10 were men and 6 women. Of these patients, 8 demonstrated perfusion abnormalities, whereas the remaining 8 showed normal myocardial perfusion imaging. In 6 of the 8 patients with abnormal SPECT, coronary angiography was performed, revealing left main trunk disease in 1 patient, 3-vessel disease in 4, 1-vessel disease with proximal left ascending artery occlusion in 1, and an insignificant lesion in 1. By contrast, no major cardiac event was observed in the 8 patients with normal SPECT during follow-up for an average of 2 years. The prevalence of ischemic ST-segment changes during ATP loading is very rare. However, this finding should be taken into account since almost half of the patients, particularly those with perfusion abnormalities, may have severe CAD which requires coronary revascularization. (author)

  8. Aqueous extract from taxus baccata inhibits adenosine deaminase activity significantly in cancerous and noncancerous human gastric and colon tissues

    Zahide Esra Durak

    2014-01-01

    Full Text Available Objective: To investigate possible effects of aqueous taxus baccata extract on adenosine deaminase (ADA activity in cancerous and noncancerous human tissues and to clarify mechanism(s of its anticancer potential. Materials and Methods: Cancerous and noncancerous human gastric and colon tissues were used in the study. The extracts were prepared in distilled water. Before and after treatment with the extracts, ADA activities in the tissue homogenates were measured. Results: ADA activity was found to be higher in gastric tissue compared with colon tissue, but no differences were found between ADA activities of cancerous and noncancerous tissues for both as well. In the plant extract studies, it was found that taxus extract significantly inhibited ADA activity both in cancerous and noncancerous gastric and colon tissues. Conclusion: Our results suggest that aqueous extract from taxus baccata inhibits ADA activities in both gastric and colon tissues significantly. It is suggested that in addition to other proposed mechanisms, accumulated adenosine due to the inhibition of ADA enzyme might also play part in the anticancer properties of taxus species.

  9. Antinociceptive effects of incarvillateine, a monoterpene alkaloid from Incarvillea sinensis, and possible involvement of the adenosine system

    Wang, Mei-Liang; Yu, Gang; Yi, Shou-Pu; Zhang, Feng-Ying; Wang, Zhi-Tong; Huang, Bin; Su, Rui-Bin; Jia, Yan-Xing; Gong, Ze-Hui

    2015-01-01

    Incarvillea sinensis is a Bignoniaceae plant used to treat rheumatism and relieve pain in traditional Chinese medicine. As a major component of I. sinensis, incarvillateine has shown analgesic activity in mice formalin tests. Using a series of animal models, this study further evaluated the effects of incarvillateine against acute, inflammatory, and neuropathic pain. Incarvillateine (10 or 20 mg/kg, i.p.) dose-dependently attenuated acetic acid-induced writhing, but did not affect thermal threshold in the hot plate test. In a Complete Freund’s Adjuvant model, incarvillateine inhibited both thermal hyperalgesia and paw edema, and increased interleukin-1β levels. Additionally, incarvillateine attenuated mechanical allodynia induced by spared nerve injury or paclitaxel, whereas normal mechanical sensation was not affected. Incarvillateine did not affect locomotor activity and time on the rotarod at analgesic doses, and no tolerance was observed after 7 consecutive daily doses. Moreover, incarvillateine-induced antinociception was attenuated by theophylline, 1,3-dipropyl-8-cyclopentylxanthine, and 3,7-dimethyl-1-propargylxanthine, but not naloxone, indicating that the effects of incarvillateine on chronic pain were related to the adenosine system, but not opioid system. These results indicate that incarvillateine is a novel analgesic compound that is effective against inflammatory and neuropathic pain, and that its effects are associated with activation of the adenosine system. PMID:26527075

  10. Lower frequency of the low activity adenosine deaminase allelic variant (ADA1*2) in schizophrenic patients Diminuição da frequência da variante alélica de baixa atividade da adenosina desaminase (ADA1*2) em pacientes esquizofrênicos

    Gustavo Pimentel Dutra; Gustavo L. Ottoni; Lara, Diogo R; Maurício Reis Bogo

    2010-01-01

    OBJECTIVE: Adenosine may play a role in the pathophysiology of schizophrenia, since it modulates the release of several neurotransmitters such as glutamate, dopamine, serotonin and acetylcholine, decreases neuronal activity by pos-synaptic hyperpolarization and inhibits dopaminergic activity. Adenosine deaminase participates in purine metabolism by converting adenosine into inosine. The most frequent functional polymorphism of adenosine deaminase (22G→A) (ADA1*2) exhibits 20-30% lower e...

  11. Adenosine can thwart antitumor immune responses elicited by radiotherapy. Therapeutic strategies alleviating protumor ADO activities

    Vaupel, Peter [Klinikum rechts der Isar, Technische Universitaet Muenchen (TUM), Department of Radiation Oncology, Munich (Germany); Multhoff, Gabriele [Klinikum rechts der Isar, Technische Universitaet Muenchen (TUM), Department of Radiation Oncology, Munich (Germany); Helmholtz Zentrum Muenchen, Institute for innovative Radiotherapy (iRT), Experimental Immune Biology, Neuherberg (Germany)

    2016-05-15

    By studying the bioenergetic status we could show that the development of tumor hypoxia is accompanied, apart from myriad other biologically relevant effects, by a substantial accumulation of adenosine (ADO). ADO has been shown to act as a strong immunosuppressive agent in tumors by modulating the innate and adaptive immune system. In contrast to ADO, standard radiotherapy (RT) can either stimulate or abrogate antitumor immune responses. Herein, we present ADO-mediated mechanisms that may thwart antitumor immune responses elicited by RT. An overview of the generation, accumulation, and ADO-related multifaceted inhibition of immune functions, contrasted with the antitumor immune effects of RT, is provided. Upon hypoxic stress, cancer cells release ATP into the extracellular space where nucleotides are converted into ADO by hypoxia-sensitive, membrane-bound ectoenzymes (CD39/CD73). ADO actions are mediated upon binding to surface receptors, mainly A2A receptors on tumor and immune cells. Receptor activation leads to a broad spectrum of strong immunosuppressive properties facilitating tumor escape from immune control. Mechanisms include (1) impaired activity of CD4 + T and CD8 + T, NK cells and dendritic cells (DC), decreased production of immuno-stimulatory lymphokines, and (2) activation of Treg cells, expansion of MDSCs, promotion of M2 macrophages, and increased activity of major immunosuppressive cytokines. In addition, ADO can directly stimulate tumor proliferation and angiogenesis. ADO mechanisms described can thwart antitumor immune responses elicited by RT. Therapeutic strategies alleviating tumor-promoting activities of ADO include respiratory hyperoxia or mild hyperthermia, inhibition of CD39/CD73 ectoenzymes or blockade of A2A receptors, and inhibition of ATP-release channels or ADO transporters. (orig.) [German] Untersuchungen des bioenergetischen Status ergaben, dass Tumorhypoxie neben vielen anderen bedeutsamen biologischen Effekten zu einem starken

  12. The Impact of Adenosine Fast Induction of Myocardial Arrest during CABG on Myocardial Expression of Apoptosis-Regulating Genes Bax and Bcl-2

    Ahmed Shalaby

    2009-01-01

    Full Text Available Background. We studied the effect of fast induction of cardiac arrest with denosine on myocardial bax and bcl-2 expression. Methods and Results. 40 elective CABG patients were allocated into two groups. The adenosine group (n=20 received 250 μg/kg adenosine into the aortic root followed by blood potassium cardioplegia. The control group received potassium cardioplegia in blood. Bcl-2 and bax were measured. Bax was reduced in the postoperative biopsies (1.38 versus 0.47, P=.002 in the control group. Bcl-2 showed a reducing tendency (0.14 versus 0.085, P=.07. After the adenosine treatment, the expression of both bax (0.52 versus 0.59, P=.4 and bcl-2 (0.104 versus 0.107, P=.4 remained unaltered after the operation. Conclusion. Open heart surgery is associated with rapid reduction in the expression of apoptosis regulating genes bax and bcl-2. Fast Adenosine induction abolished changes in their expression.

  13. Greater adenosine A2A receptor densities in cardiac and skeletal muscle in endurance-trained men: a [11C]TMSX PET study

    We examined the densities of adenosine A2A receptors in cardiac and skeletal muscles between untrained and endurance-trained subjects using positron emission tomography (PET) and [7-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine ([11C]TMSX), a newly developed radioligand for mapping adenosine A2A receptors. Five untrained and five endurance-trained subjects participated in this study. The density of adenosine A2A receptors was evaluated as the distribution volume of [11C]TMSX in cardiac and triceps brachii muscles in the resting state using PET. The distribution volume of [11C]TMSX in the myocardium was significantly greater than in the triceps brachii muscle in both groups. Further, distribution volumes [11C]TMSX in the trained subjects were significantly grater than those in untrained subjects (myocardium, 3.6±0.3 vs. 3.1±0.4 ml g-1; triceps brachii muscle, 1.7±0.3 vs. 1.2±0.2 ml g-1, respectively). These results indicate that the densities of adenosine A2A receptors in the cardiac and skeletal muscles are greater in the endurance-trained men than in the untrained men

  14. Sterol transporter adenosine triphosphate-binding cassette transporter G8, gallstones, and biliary cancer in 62,000 individuals from the general population

    Stender, Stefan; Frikke-Schmidt, Ruth; Nordestgaard, Børge G; Tybjærg-Hansen, Anne

    2011-01-01

    Gallstone disease, a risk factor for biliary cancer, has a strong heritable component, but the underlying genes are largely unknown. To test the hypothesis that ABCG8 (adenosine triphosphate-binding cassette transporter G8) Asp19His (D19H) genotype predicted risk of gallstones and biliary cancer ...

  15. Effects of a Proprietary Standardized Orthosiphon stamineus Ethanolic Leaf Extract on Enhancing Memory in Sprague Dawley Rats Possibly via Blockade of Adenosine A2A Receptors

    Choudhary, Yogendra; Choudhary, Vandana Kotak; Bommu, Praveen; Wong, Hoi Jin

    2015-01-01

    The aim of the study was to explore a propriety standardized ethanolic extract from leaves of Orthosiphon stamineus Benth in improving impairments in short-term social memory in vivo, possibly via blockade of adenosine A2A receptors (A2AR). The ethanolic extract of O. stamineus leaves showed significant in vitro binding activity of A2AR with 74% inhibition at 150 μg/ml and significant A2AR antagonist activity with 98% inhibition at 300 μg/mL. A significant adenosine A1 receptor (A1R) antagonist activity with 100% inhibition was observed at 300 μg/mL. Its effect on learning and memory was assessed via social recognition task using Sprague Dawley rats whereby the ethanolic extract of O. stamineus showed significant (p vehicle control. In comparison, the ethanolic extract of Polygonum minus aerial parts showed small change in inflexion; however, it remained insignificant in RI at 200 mg/kg p.o. Our findings suggest that the ethanolic extract of O. stamineus leaves improves memory by reversing age-related deficits in short-term social memory and the possible involvement of adenosine A1 and adenosine A2A as a target bioactivity site in the restoration of memory. PMID:26649059

  16. BDNF-induced presynaptic facilitation of GABAergic transmission in the hippocampus of young adults is dependent of TrkB and adenosine A2A receptors.

    Colino-Oliveira, Mariana; Rombo, Diogo M; Dias, Raquel B; Ribeiro, Joaquim A; Sebastião, Ana M

    2016-06-01

    Brain-derived neurotrophic factor (BDNF) and adenosine are widely recognized as neuromodulators of glutamatergic transmission in the adult brain. Most BDNF actions upon excitatory plasticity phenomena are under control of adenosine A2A receptors (A2ARs). Concerning gamma-aminobutyric acid (GABA)-mediated transmission, the available information refers to the control of GABA transporters. We now focused on the influence of BDNF and the interplay with adenosine on phasic GABAergic transmission. To assess this, we evaluated evoked and spontaneous synaptic currents recorded from CA1 pyramidal cells in acute hippocampal slices from adult rat brains (6 to 10 weeks old). BDNF (10-100 ng/mL) increased miniature inhibitory postsynaptic current (mIPSC) frequency, but not amplitude, as well as increased the amplitude of inhibitory postsynaptic currents (IPSCs) evoked by afferent stimulation. The facilitatory action of BDNF upon GABAergic transmission was lost in the presence of a Trk inhibitor (K252a, 200 nM), but not upon p75(NTR) blockade (anti-p75(NTR) IgG, 50 μg/mL). Moreover, the facilitatory action of BDNF onto GABAergic transmission was also prevented upon A2AR antagonism (SCH 58261, 50 nM). We conclude that BDNF facilitates GABAergic signaling at the adult hippocampus via a presynaptic mechanism that depends on TrkB and adenosine A2AR activation. PMID:26897393

  17. In vivo evaluation of [11C]preladenant positron emission tomography for quantification of adenosine A2A receptors in the rat brain

    Zhou, Xiaoyun; Khanapur, Shivashankar; de Jong, Johan R; Willemsen, Antoon T.M.; Dierckx, Rudi Ajo; Elsinga, Philip H; de Vries, Erik Fj

    2016-01-01

    [(11)C]Preladenant was developed as a novel adenosine A2A receptor positron emission tomography radioligand. The present study aims to evaluate the suitability of [(11)C]preladenant positron emission tomography for the quantification of striatal A2A receptor density and the assessment of striatal A2

  18. Adenosine derived from Staphylococcus aureus-engulfed macrophages functions as a potent stimulant for the induction of inflammatory cytokines in mast cells

    Ma, Ying Jie; Kim, Chan-Hee; Ryu, Kyoung-Hwa; Kim, Min-Su; So, Young-In; Lee, Kong-Joo; Garred, Peter; Lee, Bok-Luel

    2011-01-01

    molecule was purified to homogeneity through a C(18) reverse phase HPLC column. By determination of its structure by MALDITOF and (1)H- and (13)C-NMR, adenosine was revealed to be responsible for the observed cytokine induction activities. Further studies using 8-sulfophenyl theophylline, a selective...

  19. Activation of adenosine A3 receptors supports hematopoiesis-stimulating effects of granulocyte colony-stimulating factor in sublethally irradiated mice

    Hofer, Michal; Pospíšil, Milan; Šefc, L.; Dušek, L.; Vacek, Antonín; Holá, Jiřina; Hoferová, Zuzana; Štreitová, Denisa

    2010-01-01

    Roč. 86, č. 8 (2010), s. 649-656. ISSN 0955-3002 R&D Projects: GA ČR(CZ) GA305/08/0158 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : ionising radiation * hematopoiesis * adenosine A3 receptors Subject RIV: BO - Biophysics Impact factor: 1.861, year: 2010

  20. Plaque retention by self-ligating vs elastomeric orthodontic brackets: quantitative comparison of oral bacteria and detection with adenosine triphosphate-driven bioluminescence.

    Pellegrini, P.; Sauerwein, R.W.; Finlayson, T.; McLeod, J.; Covell, D.A.; Maier, T.; Machida, C.A.

    2009-01-01

    INTRODUCTION: Enamel decalcification is a common problem in orthodontics. The objectives of this randomized clinical study were to enumerate and compare plaque bacteria surrounding 2 bracket types, self-ligating (SL) vs elastomeric ligating (E), and to determine whether adenosine triphosphate (ATP)-