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Daniels SD, Boison D. Bipolar mania and epilepsy pathophysiology and treatment may converge in purine metabolism: A new perspective on available evidence. Neuropharmacology 2023; 241:109756. [PMID: 37820933 PMCID: PMC10841508 DOI: 10.1016/j.neuropharm.2023.109756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 09/25/2023] [Accepted: 10/07/2023] [Indexed: 10/13/2023]
Abstract
Decreased ATPergic signaling is an increasingly recognized pathophysiology in bipolar mania disease models. In parallel, adenosine deficit is increasingly recognized in epilepsy pathophysiology. Under-recognized ATP and/or adenosine-increasing mechanisms of several antimanic and antiseizure therapies including lithium, valproate, carbamazepine, and ECT suggest a fundamental pathogenic role of adenosine deficit in bipolar mania to match the established role of adenosine deficit in epilepsy. The depletion of adenosine-derivatives within the purine cycle is expected to result in a compensatory increase in oxopurines (uric acid precursors) and secondarily increased uric acid, observed in both bipolar mania and epilepsy. Cortisol-based inhibition of purine conversion to adenosine-derivatives may be reflected in observed uric acid increases and the well-established contribution of cortisol to both bipolar mania and epilepsy pathology. Cortisol-inhibited conversion from IMP to AMP as precursor of both ATP and adenosine may represent a mechanism for treatment resistance common in both bipolar mania and epilepsy. Anti-cortisol therapies may therefore augment other treatments both in bipolar mania and epilepsy. Evidence linking (i) adenosine deficit with a decreased need for sleep, (ii) IMP/cGMP excess with compulsive hypersexuality, and (iii) guanosine excess with grandiose delusions may converge to suggest a novel theory of bipolar mania as a condition characterized by disrupted purine metabolism. The potential for disease-modification and prevention related to adenosine-mediated epigenetic changes in epilepsy may be mirrored in mania. Evaluating the purinergic effects of existing agents and validating purine dysregulation may improve diagnosis and treatment in bipolar mania and epilepsy and provide specific targets for drug development.
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Affiliation(s)
- Scott D Daniels
- Hutchings Psychiatric Center, New York State Office of Mental Health, Syracuse, NY, 13210, USA
| | - Detlev Boison
- Dept. of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854, USA.
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2
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Matsumura N, Aoyama K. Glutathione-Mediated Neuroprotective Effect of Purine Derivatives. Int J Mol Sci 2023; 24:13067. [PMID: 37685879 PMCID: PMC10487553 DOI: 10.3390/ijms241713067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/19/2023] [Accepted: 08/20/2023] [Indexed: 09/10/2023] Open
Abstract
Numerous basic studies have reported on the neuroprotective properties of several purine derivatives such as caffeine and uric acid (UA). Epidemiological studies have also shown the inverse association of appropriate caffeine intake or serum urate levels with neurodegenerative diseases such as Alzheimer disease (AD) and Parkinson's disease (PD). The well-established neuroprotective mechanisms of caffeine and UA involve adenosine A2A receptor antagonism and antioxidant activity, respectively. Our recent study found that another purine derivative, paraxanthine, has neuroprotective effects similar to those of caffeine and UA. These purine derivatives can promote neuronal cysteine uptake through excitatory amino acid carrier protein 1 (EAAC1) to increase neuronal glutathione (GSH) levels in the brain. This review summarizes the GSH-mediated neuroprotective effects of purine derivatives. Considering the fact that GSH depletion is a manifestation in the brains of AD and PD patients, administration of purine derivatives may be a new therapeutic approach to prevent or delay the onset of these neurodegenerative diseases.
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Affiliation(s)
- Nobuko Matsumura
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
| | - Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi, Tokyo 173-8605, Japan
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Fagundes AC, de Oliveira ED, Ferrari SG, Dos Santos LMM, Botelho LM, Schmidt SRG, Andrade CF, Lara DR, Souza DO, Schmidt AP. Allopurinol for fibromyalgia pain in adults: A randomized controlled trial. Pain Pract 2021; 22:19-27. [PMID: 33864725 DOI: 10.1111/papr.13019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/09/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Allopurinol is a potent inhibitor of the enzyme xanthine oxidase used in the treatment of hyperuricemia and gout. Because it is well known that purines exert multiple affects on pain transmission, we hypothesized that the inhibition of xanthine oxidase by allopurinol could be a valid strategy to treat pain in humans. This study aimed to compare the analgesic efficacy of oral allopurinol versus placebo as an adjuvant therapy in patients displaying fibromyalgia. METHODS This randomized, double-blinded, placebo-controlled study included 60 women with the diagnosis of fibromyalgia. Patients were randomly assigned to receive either oral allopurinol 300 mg (n = 31) or placebo (n = 29) twice daily during 30 days. The patients were submitted to evaluation for pain sensitivity, anxiety, depression, and functional status before treatment, and 15 and 30 days thereafter. RESULTS Oral administration of allopurinol 300 mg twice daily was ineffective in improving pain scores measured by several tools up to 30 days of treatment (P > 0.05). Additionally, no significant effects of allopurinol over anxiety, depressive symptoms, and functional status of fibromyalgia patients were observed in the present study. CONCLUSIONS Although previous findings indicated that allopurinol could present intrinsic analgesic effects in both animals and humans, this study showed no benefit of the use of oral allopurinol as an adjuvant strategy during 30 days in women displaying fibromyalgia. However, considering previous promising results, new prospective studies are still valid to further investigate allopurinol and more selective purine derivatives in the management of pain syndromes.
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Affiliation(s)
- Aécio C Fagundes
- Department of Biochemistry, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Enderson D de Oliveira
- Department of Biochemistry, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Samira G Ferrari
- Department of Anesthesia and Perioperative Medicine, Hospital de Clínicas de Porto Alegre (HCPA), UFRGS, Porto Alegre, RS, Brazil
| | - Lúcia M M Dos Santos
- Department of Pain and Palliative Care, Hospital de Clínicas de Porto Alegre (HCPA), UFRGS, Porto Alegre, RS, Brazil
| | - Leonardo M Botelho
- Department of Pain and Palliative Care, Hospital de Clínicas de Porto Alegre (HCPA), UFRGS, Porto Alegre, RS, Brazil
| | - Sérgio R G Schmidt
- Pain S.O.S., Pain Relief Center, Medical Center of Hospital Mãe de Deus, Porto Alegre, RS, Brazil
| | - Cristiano F Andrade
- Postgraduate Program in Pneumological Sciences, UFRGS, Porto Alegre, RS, Brazil
| | - Diogo R Lara
- Cingulo Mental Health App, Porto Alegre, RS, Brazil
| | - Diogo O Souza
- Department of Biochemistry, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - André P Schmidt
- Department of Biochemistry, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.,Department of Anesthesia and Perioperative Medicine, Hospital de Clínicas de Porto Alegre (HCPA), UFRGS, Porto Alegre, RS, Brazil.,Pain S.O.S., Pain Relief Center, Medical Center of Hospital Mãe de Deus, Porto Alegre, RS, Brazil.,Postgraduate Program in Pneumological Sciences, UFRGS, Porto Alegre, RS, Brazil.,Department of Anesthesia, Santa Casa de Porto Alegre, Universidade Federal de Ciências Médicas de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.,Department of Anesthesia, Hospital Nossa Senhora da Conceição, Porto Alegre, RS, Brazil
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4
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Cipriani S, Bakshi R, Schwarzschild MA. Protection by inosine in a cellular model of Parkinson's disease. Neuroscience 2014; 274:242-9. [PMID: 24880154 DOI: 10.1016/j.neuroscience.2014.05.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 05/14/2014] [Accepted: 05/16/2014] [Indexed: 02/06/2023]
Abstract
Inosine (hypoxanthine 9-beta-D-ribofuranoside), a purine nucleoside with multiple intracellular roles, also serves as an extracellular modulatory signal. On neurons, it can produce anti-inflammatory and trophic effects that confer protection against toxic influences in vivo and in vitro. The protective effects of inosine treatment might also be mediated by its metabolite urate. Urate in fact possesses potent antioxidant properties and has been reported to be protective in preclinical Parkinson's disease (PD) studies and to be an inverse risk factor for both the development and progression of PD. In this study we assessed whether inosine might protect rodent MES 23.5 dopaminergic cell line from oxidative stress in a cellular model of PD, and whether its effects could be attributed to urate. MES 23.5 cells cultured alone or in presence of enriched murine astroglial cultures MES 23.5-astrocytes co-cultures were pretreated with inosine (0.1-100 μM) for 24 h before addition of the oxidative stress inducer H₂O₂ (200 μM). Twenty-four hours later, cell viability was quantified by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay or immunocytochemistry in pure and MES 23.5-astrocytes co-cultures, respectively. H₂O₂-toxic effect on dopaminergic cells was reduced when they were cultured with astrocytes, but not when they were cultured alone. Moreover, in MES 23.5-astrocytes co-cultures, indicators of free radical generation and oxidative damage, evaluated by nitrite (NO₂(-)) release and protein carbonyl content, respectively, were attenuated. Conditioned medium experiments indicated that the protective effect of inosine relies on the release of a protective factor from inosine-stimulated astrocytes. Purine levels were measured in the cellular extract and conditioned medium using high-performance liquid chromatography (HPLC) method. Urate concentration was not significantly increased by inosine treatment however there was a significant increase in levels of other purine metabolites, such as adenosine, hypoxanthine and xanthine. In particular, in MES 23.5-astrocytes co-cultures, inosine medium content was reduced by 99% and hypoxanthine increased by 127-fold. Taken together these data raise the possibility that inosine might have a protective effect in PD that is independent of any effects mediated through its metabolite urate.
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Affiliation(s)
- S Cipriani
- Molecular Neurobiology Laboratory, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, 114 16th street, Boston, MA 02129, USA.
| | - R Bakshi
- Molecular Neurobiology Laboratory, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, 114 16th street, Boston, MA 02129, USA
| | - M A Schwarzschild
- Molecular Neurobiology Laboratory, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, 114 16th street, Boston, MA 02129, USA
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Pani AK, Jiao Y, Sample KJ, Smeyne RJ. Neurochemical measurement of adenosine in discrete brain regions of five strains of inbred mice. PLoS One 2014; 9:e92422. [PMID: 24642754 PMCID: PMC3958516 DOI: 10.1371/journal.pone.0092422] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 02/21/2014] [Indexed: 12/28/2022] Open
Abstract
Adenosine (ADO), a non-classical neurotransmitter and neuromodulator, and its metabolites adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP), have been shown to play an important role in a number of biochemical processes. Although their signaling is well described, it has been difficult to directly, accurately and simultaneously quantitate these purines in tissue or fluids. Here, we describe a novel method for measuring adenosine (ADO) and its metabolites using high performance liquid chromatography with electrochemical detection (HPLC-ECD). Using this chromatographic technique, we examined baseline levels of ADO and ATP, ADP and AMP in 6 different brain regions of the C57BL/6J mouse: stratum, cortex, hippocampus, olfactory bulb, substantia nigra and cerebellum and compared ADO levels in 5 different strains of mice (C57BL/6J, Swiss-Webster, FVB/NJ, 129P/J, and BALB/c). These studies demonstrate that baseline levels of purines vary significantly among the brain regions as well as between different mouse strains. These dissimilarities in purine concentrations may explain the variable phenotypes among background strains described in neurological disease models.
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Affiliation(s)
- Amar K. Pani
- Department of Developmental Neurobiology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Yun Jiao
- Department of Developmental Neurobiology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Kenneth J. Sample
- Department of Developmental Neurobiology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Richard J. Smeyne
- Department of Developmental Neurobiology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
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Gender- and age-dependent changes in nucleoside levels in the cerebral cortex and white matter of the human brain. Brain Res Bull 2010; 81:579-84. [DOI: 10.1016/j.brainresbull.2009.10.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Accepted: 10/12/2009] [Indexed: 12/13/2022]
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Zamzow CR, Xiong W, Parkinson FE. Adenosine produced by neurons is metabolized to hypoxanthine by astrocytes. J Neurosci Res 2009; 86:3447-55. [PMID: 18627033 DOI: 10.1002/jnr.21789] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Adenosine (ADO) is an important neuromodulator in brain. During pathophysiological events such as stroke or brain trauma, ADO levels can increase up to 100-fold. We tested the hypothesis that astrocytes are important for the removal of ADO produced by neurons and for the metabolism of ADO to inosine (INO) and hypoxanthine (HX). We used four different cell culture preparations: cortical neurons, cortical astrocytes, cocultures of neurons and astrocytes, and neurons transiently cocultured with astrocytes on transwell filters. These cultures were treated with N-methyl-D-aspartate (NMDA), because NMDA receptor activation is a common factor among many causes of neurotoxicity. NMDA significantly increased extracellular ADO, INO, and HX levels from cultured cortical neurons by 3-, 3.5-, and 2-fold, respectively. In cocultures, NMDA significantly increased INO, by 4.5-fold, and HX, by 3-fold, but did not increase ADO levels. There was no NMDA-evoked purine production from astrocytes. Inhibition of purine nucleoside phosphorylase (PNP) significantly decreased HX production from both neurons and cocultures to less than 30% of control levels. The transient addition of astrocytes to neurons during NMDA treatment significantly increased HX and decreased ADO levels compared with neurons alone. In addition, increasing the number of astrocytes was directly correlated with an increased capacity of ADO metabolism to INO and HX. In conclusion, NMDA evoked the production of ADO, INO, and HX from neurons. In the presence of astrocytes, there was significantly less ADO and more HX produced. Thus, ADO produced by neurons is subject to metabolism by astrocytes, a process that may limit its neuromodulatory actions.
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Affiliation(s)
- Christina R Zamzow
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
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9
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Schmidt AP, Böhmer AE, Antunes C, Schallenberger C, Porciúncula LO, Elisabetsky E, Lara DR, Souza DO. Anti-nociceptive properties of the xanthine oxidase inhibitor allopurinol in mice: role of A1 adenosine receptors. Br J Pharmacol 2009; 156:163-72. [PMID: 19133997 PMCID: PMC2697763 DOI: 10.1111/j.1476-5381.2008.00025.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 07/25/2008] [Accepted: 09/02/2008] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Allopurinol is a potent inhibitor of the enzyme xanthine oxidase, used primarily in the treatment of hyperuricemia and gout. It is well known that purines exert multiple effects on pain transmission. We hypothesized that the inhibition of xanthine oxidase by allopurinol, thereby reducing purine degradation, could be a valid strategy to enhance purinergic activity. The aim of this study was to investigate the anti-nociceptive profile of allopurinol on chemical and thermal pain models in mice. EXPERIMENTAL APPROACH Mice received an intraperitoneal (i.p.) injection of vehicle (Tween 10%) or allopurinol (10-400 mg kg(-1)). Anti-nociceptive effects were measured with intraplantar capsaicin, intraplantar glutamate, tail-flick or hot-plate tests. KEY RESULTS Allopurinol presented dose-dependent anti-nociceptive effects in all models. The opioid antagonist naloxone did not affect these anti-nociceptive effects. The non-selective adenosine-receptor antagonist caffeine and the selective A(1) adenosine-receptor antagonist, DPCPX, but not the selective A(2A) adenosine-receptor antagonist, SCH58261, completely prevented allopurinol-induced anti-nociception. No obvious motor deficits were produced by allopurinol, at doses up to 200 mg kg(-1). Allopurinol also caused an increase in cerebrospinal fluid levels of purines, including the nucleosides adenosine and guanosine, and decreased cerebrospinal fluid concentration of uric acid. CONCLUSIONS AND IMPLICATIONS Allopurinol-induced anti-nociception may be related to adenosine accumulation. Allopurinol is an old and extensively used compound and seems to be well tolerated with no obvious central nervous system toxic effects at high doses. This drug may be useful to treat pain syndromes in humans.
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Affiliation(s)
- A P Schmidt
- Department of Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Toscano CD, Prabhu VV, Langenbach R, Becker KG, Bosetti F. Differential gene expression patterns in cyclooxygenase-1 and cyclooxygenase-2 deficient mouse brain. Genome Biol 2007; 8:R14. [PMID: 17266762 PMCID: PMC1839133 DOI: 10.1186/gb-2007-8-1-r14] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 11/09/2006] [Accepted: 01/31/2007] [Indexed: 12/30/2022] Open
Abstract
Microarray analysis of gene expression in the cerebral cortex and hippocampus of mice deficient in cyclooxygenase-1 or cyclooxygenase-2 reveals that the two enzymes differentially modulate brain gene expression. Background Cyclooxygenase (COX)-1 and COX-2 produce prostanoids from arachidonic acid and are thought to have important yet distinct roles in normal brain function. Deletion of COX-1 or COX-2 results in profound differences both in brain levels of prostaglandin E2 and in activation of the transcription factor nuclear factor-κB, suggesting that COX-1 and COX-2 play distinct roles in brain arachidonic acid metabolism and regulation of gene expression. To further elucidate the role of COX isoforms in the regulation of the brain transcriptome, microarray analysis of gene expression in the cerebral cortex and hippocampus of mice deficient in COX-1 (COX-1-/-) or COX-2 (COX-2-/-) was performed. Results A majority (>93%) of the differentially expressed genes in both the cortex and hippocampus were altered in one COX isoform knockout mouse but not the other. The major gene function affected in all genotype comparisons was 'transcriptional regulation'. Distinct biologic and metabolic pathways that were altered in COX-/- mice included β oxidation, methionine metabolism, janus kinase signaling, and GABAergic neurotransmission. Conclusion Our findings suggest that COX-1 and COX-2 differentially modulate brain gene expression. Because certain anti-inflammatory and analgesic treatments are based on inhibition of COX activity, the specific alterations observed in this study further our understanding of the relationship of COX-1 and COX-2 with signaling pathways in brain and of the therapeutic and toxicologic consequences of COX inhibition.
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Affiliation(s)
- Christopher D Toscano
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg. 9, Rm. 1S126, 9 Memorial Drive, Bethesda, Maryland 20892, USA
| | - Vinaykumar V Prabhu
- Gene Expression and Genomics Unit, National Institute on Aging, National Institutes of Health, Gerontology Research Center, 5600 Nathan Shock Drive, Baltimore, Maryland, 21224, USA
| | - Robert Langenbach
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Drive, Research Triangle Park, North Carolina, 27709, USA
| | - Kevin G Becker
- Gene Expression and Genomics Unit, National Institute on Aging, National Institutes of Health, Gerontology Research Center, 5600 Nathan Shock Drive, Baltimore, Maryland, 21224, USA
| | - Francesca Bosetti
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg. 9, Rm. 1S126, 9 Memorial Drive, Bethesda, Maryland 20892, USA
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Tumini E, Porcellini E, Chiappelli M, Conti CM, Beraudi A, Poli A, Caciagli F, Doyle R, Conti P, Licastro F. The G51S purine nucleoside phosphorylase polymorphism is associated with cognitive decline in Alzheimer's disease patients. Hum Psychopharmacol 2007; 22:75-80. [PMID: 17221831 DOI: 10.1002/hup.823] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Alzheimer's disease (AD) is a polygenic and multifactorial complex disease, whose etiopathology is still unclear, however several genetic factors have shown to increase the risk of developing the disease. Purine nucleotides and nucleosides play an important role in the brain. Besides their role in neurotransmission and neuromodulation, they are involved in trophic factor release, apoptosis, and inflammatory responses. These mediators may also have a pivotal role in the control of neurodegenerative processes associated with AD. In this report the distribution of the exonic G/A single nucleotide polymorphism (SNP) in purine nucleoside phosphorylase (PNP) gene, resulting in the amino acid substitution serine to glycine at position 51 (G51S), was investigated in a large population of AD patients (n=321) and non-demented control (n=208). The PNP polymorphism distribution was not different between patients and controls. The polymorphism distribution was also analyzed in AD patients stratified according to differential progressive rate of cognitive decline during a 2-year follow-up. An increased representation of the PNP AA genotype was observed in AD patients with fast cognitive deterioration in comparison with that from patients with slow deterioration rate. Our findings suggest that the G51S PNP polymorphism is associated with a faster rate of cognitive decline in AD patients, highlighting the important role of purine metabolism in the progression of this neurodegenerative disorder.
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Affiliation(s)
- Emanuela Tumini
- Department of Experimental Pathology, University of Bologna, Italy, Psychiatric Department Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Kékesi KA, Kovács Z, Szilágyi N, Bobest M, Szikra T, Dobolyi A, Juhász G, Palkovits M. Concentration of Nucleosides and Related Compounds in Cerebral and Cerebellar Cortical Areas and White Matter of the Human Brain. Cell Mol Neurobiol 2006; 26:833-44. [PMID: 16897364 DOI: 10.1007/s10571-006-9103-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Accepted: 09/26/2005] [Indexed: 12/11/2022]
Abstract
1. Nucleosides potentially participate in the neuronal functions of the brain. However, their distribution and changes in their concentrations in the human brain is not known. For better understanding of nucleoside functions, changes of nucleoside concentrations by age and a complete map of nucleoside levels in the human brain are actual requirements. 2. We used post mortem human brain samples in the experiments and applied a recently modified HPLC method for the measurement of nucleosides. To estimate concentrations and patterns of nucleosides in alive human brain we used a recently developed reverse extrapolation method and multivariate statistical analyses. 3. We analyzed four nucleosides and three nucleobases in human cerebellar, cerebral cortices and in white matter in young and old adults. Average concentrations of the 308 samples investigated (mean+/-SEM) were the following (pmol/mg wet tissue weight): adenosine 10.3+/-0.6, inosine 69.5+/-1.7, guanosine 13.5+/-0.4, uridine 52.4+/-1.2, uracil 8.4+/-0.3, hypoxanthine 108.6+/-2.0 and xanthine 54.8+/-1.3. We also demonstrated that concentrations of inosine and adenosine in the cerebral cortex and guanosine in the cerebral white matter are age-dependent. 4. Using multivariate statistical analyses and degradation coefficients, we present an uneven regional distribution of nucleosides in the human brain. The methods presented here allow to creation of a nucleoside map of the human brain by measuring the concentration of nucleosides in microdissected tissue samples. Our data support a functional role for nucleosides in the brain.
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Affiliation(s)
- Katalin A Kékesi
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, Hungary
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Aliefendioğlu D, Gürsoy T, Hayran KM, Aslan AT. Can cerebrospinal fluid uric acid levels differentiate intraventricular hemorrhage from traumatic tap? Neonatology 2006; 90:268-72. [PMID: 16809910 DOI: 10.1159/000094319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Accepted: 02/13/2006] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To measure blood and cerebrospinal fluid (CSF) uric acid (UA) levels of neonates with intraventricular hemorrhage (IVH), and to examine whether or not UA can be used to differentiate traumatic tap from IVH. MATERIAL AND METHODS The control group (n = 19, group I) consisted of neonates presenting with signs requiring analysis of CSF but whose CSF indices proved to be normal. Traumatic taps (n = 15, group II) were mimicked by adding 2 drops of homologous blood to normal CSF samples. The IVH group (n = 21, group III) consisted of neonates who had been diagnosed by cranial ultrasonography or computed tomography scans. Data are presented as median (range). RESULTS There was no significant difference between groups with respect to serum UA levels. While no significant difference was observed between CSF UA levels of the control [0.6 (0.1-1.8) mg/dl] and traumatic tap group [0.5 (0.3-1.1) mg/dl], the IVH group [1.6 (0.7-6.9) mg/dl] was found to have significantly higher CSF UA levels than groups I and II. Furthermore, although there were significant correlations between serum and CSF UA levels in the control and traumatic tap groups, no correlation was observed in the IVH group. CONCLUSION CSF UA levels are increased in neonates with IVH and they may be used to differentiate a real hemorrhage from a traumatic tap.
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Affiliation(s)
- Didem Aliefendioğlu
- Neonatology Unit, Department of Pediatrics, Kirikkale University Faculty of Medicine, Kirikkale, Turkey.
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Fredholm BB, Chen JF, Cunha RA, Svenningsson P, Vaugeois JM. Adenosine and Brain Function. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2005; 63:191-270. [PMID: 15797469 DOI: 10.1016/s0074-7742(05)63007-3] [Citation(s) in RCA: 494] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Bertil B Fredholm
- Department of Physiology and Pharmacology, Karolinska Institutet Stockholm, Sweden
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Castillo-Hernandez JR, Rubio-Gayosso I, Sada-Ovalle I, Garcia-Vazquez A, Ceballos G, Rubio R. Intracoronary Angiotensin II causes inotropic and vascular effects via different paracrine mechanisms. Vascul Pharmacol 2004; 41:147-58. [PMID: 15607498 DOI: 10.1016/j.vph.2004.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Accepted: 08/19/2004] [Indexed: 10/26/2022]
Abstract
We hypothesized that Angiotensin II (Ang II), like other circulating hormones, acts exclusively intravascularly. To activate or block solely intravascular Ang II receptors, Ang II and its peptide receptor blocker saralasin (Sar) were covalently coupled to a inert polymer (POL, MW >4000 kD) forming Ang II-POL and Sar-POL. These two nonpermeable polymers, Ang II and Sar, were intracoronarily administered into the isolated, saline-perfused rat hearts. Ang II-POL and Ang II caused a dose-dependent ventricular positive inotropic (+I) and vasoconstrictor effects (+V) which were blocked by Sar. Sar-POL blocked their +I but not their +V. Thus, Ang II and Ang II-POL act on endothelial luminal receptors through paracrine mechanisms. +I were blocked solely by purinoceptor antagonists and paralleled by augmented venous release of ATP degradation products (adenosine, inosine and hypoxanthine). In contrast, +V were blocked solely by aspirin, indomethacin or a thromboxane A2 receptor antagonist. Intracoronary administration of ATP-gamma-S and U46169, a purinergic, and TXA2 agonists, respectively, mimicked +I and +V. The results indicate that ATP is the paracrine inotropic mediator while thromboxane A2 is the vasoconstrictor mediator. Thus, the +I and +V distinct effects by intracoronary Ang II indicate that its diverse mechanism of action along the coronary vascular tree may be due to a functionally heterogeneous endothelium.
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Affiliation(s)
- Jesus R Castillo-Hernandez
- Departamento de Fisiologia, Facultad de Medicina, UASLP, Av. Venustiano Carranza 2405, San Luis Potosi, SLP. 78210, Mexico
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16
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Shin CY, Jang ES, Choi JW, Ryu JR, Kim WK, Kim HC, Choi CR, Ko KH. Adenosine and purine nucleosides protect rat primary astrocytes from peroxynitrite-potentiated, glucose deprivation-induced death: preservation of intracellular ATP level. Exp Neurol 2002; 176:175-82. [PMID: 12093094 DOI: 10.1006/exnr.2002.7913] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previously we have reported that immunostimulated astrocytes became highly vulnerable to glucose deprivation. In the present study we examined the effect of various kinds of nucleosides on the augmented death of glucose-deprived immunostimulated astrocytes. Preincubation with interferon-gamma (100 U/ml) and lipopolysaccharide (1 microg/ml) for 48 h and continuous exposure to glucose deprivation (4 h) significantly induced the lactate dehydrogenase (LDH) release, as a marker of cell injury or death, from astrocytes. The glucose deprivation-induced augmented cell death in immunostimulated astrocytes was mimicked by exogenous peroxynitrite generator 3-morpholinosydnonimine (SIN-1). The increased death in immunostimulated or SIN-1-treated astrocytes deprived of glucose was blocked by adenosine and ATP. Other purine nucleos(t)ides, not pyrimidine nucleotides, also showed similar protective effects. Adenosine receptor agonist R(-)-N-(2-phenylisopropyl)-adenosine or N-cyclohexyladenosine did not alter the augmented cell death. Adenosine receptor antagonists 8-cyclopentyl-1,3-dipropylxanthine, xanthine amine congener or 3,7-dimethyl-1-propargylxanthine also did not reverse the protective effect of adenosine. Intracellular ATP levels rapidly decreased prior to the LDH release in glucose-deprived immunostimulated astrocytes. The loss of intracellular ATP was prevented by adenosine and other purine nucleotides. The present results suggest that adenosine and their metabolites may protect astrocytes from peroxynitrite-potentiated, glucose deprivation-induced death by serving as substrates for intracellular ATP generation.
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Affiliation(s)
- Chan Young Shin
- Department of Pharmacology, Seoul National University, Seoul, Korea
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17
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Di Iorio P, Kleywegt S, Ciccarelli R, Traversa U, Andrew CM, Crocker CE, Werstiuk ES, Rathbone MP. Mechanisms of apoptosis induced by purine nucleosides in astrocytes. Glia 2002; 38:179-90. [PMID: 11968056 DOI: 10.1002/glia.10055] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Astrocytes release adenine-based and guanine-based purines under physiological and, particularly, pathological conditions. Thus, the aim of this study was to determine if adenosine induced apoptosis in cultured rat astrocytes. Further, if guanosine, which increases the extracellular concentration of adenosine, also induced apoptosis determined using the TUNEL and Annexin V assays. Adenosine induced apoptosis in a concentration-dependent manner up to 100 microM. Inosine, hypoxanthine, guanine, and guanosine did not. Guanosine or adenosine (100 microM) added to the culture medium was metabolized, with 35% or 15%, respectively, remaining after 2-3 h. Guanosine evoked the extracellular accumulation of adenosine, and particularly of adenine-based nucleotides. Cotreatment with EHNA and guanosine increased the extracellular accumulation of adenosine and induced apoptosis. Inhibition of the nucleoside transporters using NBTI (100 microM) or propentophylline (100 microM) significantly decreased but did not abolish the apoptosis induced by guanosine + EHNA or adenosine + EHNA, respectively. Apoptosis produced by either guanosine + EHNA or adenosine + EHNA was unaffected by A(1) or A(2) adenosine receptor antagonists, but was significantly reduced by MRS 1523, a selective A(3) adenosine receptor antagonist. Adenosine + EHNA, not guanosine + EHNA, significantly increased the intracellular concentration of S-adenosyl-L-homocysteine (SAH) and greatly reduced the ratio of S-adenosyl-L-methioine to SAH, which is associated with apoptosis. These data demonstrate that adenosine mediates apoptosis of astrocytes both, via activation of A(3) adenosine receptors and by modulating SAH hydrolase activity. Guanosine induces apoptosis by accumulating extracellular adenosine, which then acts solely via A(3) adenosine receptors.
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Affiliation(s)
- Patrizia Di Iorio
- Department of Biomedical Sciences, School of Medicine, University of Chieti, Italy
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18
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Abstract
It has been reported that inosine has no direct neuroprotection against respiratory inhibitors due to the absence of purine nucleoside phosphorylase in neurons. Recent evidence, however, has shown that inosine has direct neurotrophic effects. Thus, lack of direct neuroprotection, as reported before, may not be a general conclusion, but is related to special types of injury. We used PC12 cells to explore direct neuroprotection of inosine against high concentration of zinc sulfate, an injury different from the previous one and found that inosine reduced the mortality of PC12 cells significantly in a dose dependent manner. The results indicate that inosine can directly protect neurons from zinc-induced injury, and such effect might be mediated via mechanism(s) other than purine nucleoside phosphorylase.
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Affiliation(s)
- Ming Shi
- Institute of Neurosciences, The Fourth Military Medical University, Xi'an, 17 Chang Le Xi Road, 710032, PR China
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19
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Rodríguez-Núñez A, Cid E, Rodríguez-García J, Camiña F, Rodríguez-Segade S, Castro-Gago M. Concentrations of nucleotides, nucleosides, purine bases, oxypurines, uric acid, and neuron-specific enolase in the cerebrospinal fluid of children with sepsis. J Child Neurol 2001; 16:704-6. [PMID: 11575617 DOI: 10.1177/088307380101600918] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
To determine the effects of sepsis on cerebral energy metabolism, the cerebrospinal fluid adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, hypoxanthine, xanthine, and urate concentrations were determined by high-performance liquid chromatography and the neuron-specific enolase levels by means of an enzyme immunoassay method in 32 children with sepsis, without meningitis, aged between 2 months and 13 years, and in 160 age-matched controls. The septic group had significantly higher cerebrospinal fluid concentrations of inosine, adenosine, xanthine, and urate than controls. These results suggest that sepsis could provoke some degree of neuronal hypoxia and significant alterations of cerebral energy metabolism homeostasis.
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Affiliation(s)
- A Rodríguez-Núñez
- Department of Pediatrics, Hospital Clínico Universitario de Santiago, Complejo Hospitalario, Santiago de Compostela, Spain
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20
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Ciccarelli R, Ballerini P, Sabatino G, Rathbone MP, D'Onofrio M, Caciagli F, Di Iorio P. Involvement of astrocytes in purine‐mediated reparative processes in the brain. Int J Dev Neurosci 2001; 19:395-414. [PMID: 11378300 DOI: 10.1016/s0736-5748(00)00084-8] [Citation(s) in RCA: 180] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Astrocytes are involved in multiple brain functions in physiological conditions, participating in neuronal development, synaptic activity and homeostatic control of the extracellular environment. They also actively participate in the processes triggered by brain injuries, aimed at limiting and repairing brain damages. Purines may play a significant role in the pathophysiology of numerous acute and chronic disorders of the central nervous system (CNS). Astrocytes are the main source of cerebral purines. They release either adenine-based purines, e.g. adenosine and adenosine triphosphate, or guanine-based purines, e.g. guanosine and guanosine triphosphate, in physiological conditions and release even more of these purines in pathological conditions. Astrocytes express several receptor subtypes of P1 and P2 types for adenine-based purines. Receptors for guanine-based purines are being characterised. Specific ecto-enzymes such as nucleotidases, adenosine deaminase and, likely, purine nucleoside phosphorylase, metabolise both adenine- and guanine-based purines after release from astrocytes. This regulates the effects of nucleotides and nucleosides by reducing their interaction with specific membrane binding sites. Adenine-based nucleotides stimulate astrocyte proliferation by a P2-mediated increase in intracellular [Ca2+] and isoprenylated proteins. Adenosine also, via A2 receptors, may stimulate astrocyte proliferation, but mostly, via A1 and/or A3 receptors, inhibits astrocyte proliferation, thus controlling the excessive reactive astrogliosis triggered by P2 receptors. The activation of A1 receptors also stimulates astrocytes to produce trophic factors, such as nerve growth factor, S100beta protein and transforming growth factor beta, which contribute to protect neurons against injuries. Guanosine stimulates the output of adenine-based purines from astrocytes and in addition it directly triggers these cells to proliferate and to produce large amount of neuroprotective factors. These data indicate that adenine- and guanine-based purines released in large amounts from injured or dying cells of CNS may act as signals to initiate brain repair mechanisms widely involving astrocytes.
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Affiliation(s)
- R Ciccarelli
- Department of Biomedical Sciences, Section of Pharmacology, Via del Vestini Pal. B, 66013, Chieti, Italy.
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21
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Cristalli G, Costanzi S, Lambertucci C, Lupidi G, Vittori S, Volpini R, Camaioni E. Adenosine deaminase: functional implications and different classes of inhibitors. Med Res Rev 2001; 21:105-28. [PMID: 11223861 DOI: 10.1002/1098-1128(200103)21:2<105::aid-med1002>3.0.co;2-u] [Citation(s) in RCA: 211] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Adenosine deaminase (ADA) is an enzyme of the purine metabolism which catalyzes the irreversible deamination of adenosine and deoxyadenosine to inosine and deoxyinosine, respectively. This ubiquitous enzyme has been found in a wide variety of microorganisms, plants, and invertebrates. In addition, it is present in all mammalian cells that play a central role in the differentiation and maturation of the lymphoid system. However, despite a number of studies performed to date, the physiological role played by ADA in the different tissues is not clear. Inherited ADA deficiency causes severe combined immunodeficiency disease (ADA-SCID), in which both B-cell and T-cell development is impaired. ADA-SCID has been the first disorder to be treated by gene therapy, using polyethylene glycol-modified bovine ADA (PEG-ADA). Conversely, there are several diseases in which the level of ADA is above normal. A number of ADA inhibitors have been designed and synthesized, classified as ground-state and transition-state inhibitors. They may be used to mimic the genetic deficiency of the enzyme, in lymphoproliferative disorders or immunosuppressive therapy (i.e., in graft rejection), to potentiate the effect of antileukemic or antiviral nucleosides, and, together with adenosine kinase, to reduce breakdown of adenosine in inflammation, hypertension, and ischemic injury.
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Affiliation(s)
- G Cristalli
- Dipartimento di Scienze Chimiche, Università di Camerino, Via S. Agostino 1, 62032 Camerino, Italy.
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22
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Rathbone MP, Middlemiss PJ, Gysbers JW, Andrew C, Herman MA, Reed JK, Ciccarelli R, Di Iorio P, Caciagli F. Trophic effects of purines in neurons and glial cells. Prog Neurobiol 1999; 59:663-90. [PMID: 10845757 DOI: 10.1016/s0301-0082(99)00017-9] [Citation(s) in RCA: 314] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In addition to their well known roles within cells, purine nucleotides such as adenosine 5' triphosphate (ATP) and guanosine 5' triphosphate (GTP), nucleosides such as adenosine and guanosine and bases, such as adenine and guanine and their metabolic products xanthine and hypoxanthine are released into the extracellular space where they act as intercellular signaling molecules. In the nervous system they mediate both immediate effects, such as neurotransmission, and trophic effects which induce changes in cell metabolism, structure and function and therefore have a longer time course. Some trophic effects of purines are mediated via purinergic cell surface receptors, whereas others require uptake of purines by the target cells. Purine nucleosides and nucleotides, especially guanosine, ATP and GTP stimulate incorporation of [3H]thymidine into DNA of astrocytes and microglia and concomitant mitosis in vitro. High concentrations of adenosine also induce apoptosis, through both activation of cell-surface A3 receptors and through a mechanism requiring uptake into the cells. Extracellular purines also stimulate the synthesis and release of protein trophic factors by astrocytes, including bFGF (basic fibroblast growth factor), nerve growth factor (NGF), neurotrophin-3, ciliary neurotrophic factor and S-100beta protein. In vivo infusion into brain of adenosine analogs stimulates reactive gliosis. Purine nucleosides and nucleotides also stimulate the differentiation and process outgrowth from various neurons including primary cultures of hippocampal neurons and pheochromocytoma cells. A tonic release of ATP from neurons, its hydrolysis by ecto-nucleotidases and subsequent re-uptake by axons appears crucial for normal axonal growth. Guanosine and GTP, through apparently different mechanisms, are also potent stimulators of axonal growth in vitro. In vivo the extracellular concentration of purines depends on a balance between the release of purines from cells and their re-uptake and extracellular metabolism. Purine nucleosides and nucleotides are released from neurons by exocytosis and from both neurons and glia by non-exocytotic mechanisms. Nucleosides are principally released through the equilibratory nucleoside transmembrane transporters whereas nucleotides may be transported through the ATP binding cassette family of proteins, including the multidrug resistance protein. The extracellular purine nucleotides are rapidly metabolized by ectonucleotidases. Adenosine is deaminated by adenosine deaminase (ADA) and guanosine is converted to guanine and deaminated by guanase. Nucleosides are also removed from the extracellular space into neurons and glia by transporter systems. Large quantities of purines, particularly guanosine and, to a lesser extent adenosine, are released extracellularly following ischemia or trauma. Thus purines are likely to exert trophic effects in vivo following trauma. The extracellular purine nucleotide GTP enhances the tonic release of adenine nucleotides, whereas the nucleoside guanosine stimulates tonic release of adenosine and its metabolic products. The trophic effects of guanosine and GTP may depend on this process. Guanosine is likely to be an important trophic effector in vivo because high concentrations remain extracellularly for up to a week after focal brain injury. Purine derivatives are now in clinical trials in humans as memory-enhancing agents in Alzheimer's disease. Two of these, propentofylline and AIT-082, are trophic effectors in animals, increasing production of neurotrophic factors in brain and spinal cord. Likely more clinical uses for purine derivatives will be found; purines interact at the level of signal-transduction pathways with other transmitters, for example, glutamate. They can beneficially modify the actions of these other transmitters.
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Affiliation(s)
- M P Rathbone
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
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23
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Litsky ML, Hohl CM, Lucas JH, Jurkowitz MS. Inosine and guanosine preserve neuronal and glial cell viability in mouse spinal cord cultures during chemical hypoxia. Brain Res 1999; 821:426-32. [PMID: 10064830 DOI: 10.1016/s0006-8993(99)01086-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Murine spinal cord primary mixed cultures were treated with the respiratory inhibitor, rotenone, to mimic hypoxic conditions. Under these conditions neurons rapidly underwent oncosis (necrosis) with a complete loss in viability occurring within 260 min; however, astrocytes, which accounted for most of the cell population, died more slowly with 50% viability occurring at 565 min. Inosine preserved both total cell and neuronal viability in a concentration-dependent manner. The time of inosine addition relative to hypoxic insult was critical with the most effective protection occurring when inosine was added just prior to or within 5 min after insult. Inosine was ineffective when added 30 min after hypoxic insult. The effect of guanosine was similar to that of inosine. Treatment of cultures with BCX-34, a purine nucleoside phosphorylase inhibitor, prevented protection by inosine or guanosine, suggesting involvement of a purine nucleoside phosphorylase in the nucleoside protective effect.
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Affiliation(s)
- M L Litsky
- Department of Medical Biochemistry, Ohio State University, Rm 471 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USA
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24
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Grabb MC, Sciotti VM, Gidday JM, Cohen SA, van Wylen DG. Neurochemical and morphological responses to acutely and chronically implanted brain microdialysis probes. J Neurosci Methods 1998; 82:25-34. [PMID: 10223512 DOI: 10.1016/s0165-0270(98)00025-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to compare, in rats, brain microdialysis results obtained using microdialysis probes implanted acutely for 2 h versus probes implanted chronically for 24 h in the caudate. Specific comparisons included: (1) dialysate purine and amino acid profiles during cerebral ischemia; (2) diffusional characteristics of the microdialysis probe; and (3) tissue morphology surrounding the probe. During ischemia, the increase in dialysate levels of adenosine, inosine, and hypoxanthine was less pronounced from probes implanted chronically, while dialysate xanthine levels increased to a greater extent. An increase in dialysate amino acid neurotransmitters during cerebral ischemia was observed in the acutely implanted probes within 10 min of the onset of cerebral ischemia; in the chronically implanted probes this increase did not occur until after 50 min of severe ischemia. Both in vitro and in vivo tests revealed a diffusional barrier in chronically implanted probes. Moreover, the tissue surrounding chronically implanted probes exhibited a high degree of inflammation, and fibrin deposits were substantial. In addition, uric acid levels (an indicator of tissue injury) sampled from chronically implanted probes were 7-fold greater than levels sampled from acutely implanted probes. These data raise concerns about the use of chronically implanted microdialysis probes for the measurement of purine and amino acid profiles during cerebral ischemia.
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Affiliation(s)
- M C Grabb
- Department of Physiology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, 14214, USA
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25
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Stover JF, Lowitzsch K, Kempski OS. Cerebrospinal fluid hypoxanthine, xanthine and uric acid levels may reflect glutamate-mediated excitotoxicity in different neurological diseases. Neurosci Lett 1997; 238:25-8. [PMID: 9464646 DOI: 10.1016/s0304-3940(97)00840-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Glutamate-mediated excitotoxicity is associated with adenosine triphosphate (ATP) degradation and generation of oxygen radicals. Hypoxanthine and lactate depict energetic impairment, while xanthine and uric acid reflect activity of radical producing xanthine oxidase. Cerebrospinal fluid (CSF) glutamate, hypoxanthine, lactate, xanthine, and uric acid were investigated in neurological patients. In multiple sclerosis, myelopathy, stroke, epilepsy and viral meningitis glutamate, hypoxanthine, xanthine, and uric acid are increased 2-3-fold compared to controls. Lactate is only elevated in meningitis. Normal lactate dehydrogenase (LDH) levels and absent correlation between the albumin ratio and neurochemical parameters exclude an artificial increase due to cell lysis and barrier damage. Absent correlation between neurochemical parameters within each patient group is most likely related to preserved glial and neuronal uptake mechanisms. CSF hypoxanthine, xanthine, and uric acid levels appear superior to lactate in reflecting glutamate-mediated excitotoxicity in neurological patients.
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Affiliation(s)
- J F Stover
- Institute for Neurosurgical Pathophysiology, Mainz, Germany
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26
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Peuchen S, Bolaños JP, Heales SJ, Almeida A, Duchen MR, Clark JB. Interrelationships between astrocyte function, oxidative stress and antioxidant status within the central nervous system. Prog Neurobiol 1997; 52:261-81. [PMID: 9247965 DOI: 10.1016/s0301-0082(97)00010-5] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Astrocytes have, until recently, been thought of as the passive supporting elements of the central nervous system. However, recent developments suggest that these cells actually play a crucial and vital role in the overall physiology of the brain. Astrocytes selectively express a host of cell membrane and nuclear receptors that are responsive to various neuroactive compounds. In addition, the cell membrane has a number of important transporters for these compounds. Direct evidence for the selective co-expression of neurotransmitters, transporters on both neurons and astrocytes, provides additional evidence for metabolic compartmentation within the central nervous system. Oxidative stress as defined by the excessive production of free radicals can alter dramatically the function of the cell. The free radical nitric oxide has attracted a considerable amount of attention recently, due to its role as a physiological second messenger but also because of its neurotoxic potential when produced in excess. We provide, therefore, an in-depth discussion on how this free radical and its metabolites affect the intra and intercellular physiology of the astrocyte(s) and surrounding neurons. Finally, we look at the ways in which astrocytes can counteract the production of free radicals in general by using their antioxidant pathways. The glutathione antioxidant system will be the focus of attention, since astrocytes have an enormous capacity for, and efficiency built into this particular system.
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Affiliation(s)
- S Peuchen
- Department of Neurochemistry, Institute of Neurology, London, U.K.
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27
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Brundege JM, Dunwiddie TV. Role of adenosine as a modulator of synaptic activity in the central nervous system. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 1997; 39:353-91. [PMID: 9160120 DOI: 10.1016/s1054-3589(08)60076-9] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- J M Brundege
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver 80262, USA
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28
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Okuda S, Nishiyama N, Saito H, Katsuki H. Hydrogen peroxide-mediated neuronal cell death induced by an endogenous neurotoxin, 3-hydroxykynurenine. Proc Natl Acad Sci U S A 1996; 93:12553-8. [PMID: 8901620 PMCID: PMC38030 DOI: 10.1073/pnas.93.22.12553] [Citation(s) in RCA: 220] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
3-Hydroxykynurenine (3-HK) is a tryptophan metabolite whose level in the brain is markedly elevated under several pathological conditions, including Huntington disease and human immunodeficiency virus infection. Here we demonstrate that micromolar concentrations (1-100 microM) of 3-HK cause cell death in primary neuronal cultures prepared from rat striatum. The neurotoxicity of 3-HK was blocked by catalase and desferrioxamine but not by superoxide dismutase, indicating that the generation of hydrogen peroxide and hydroxyl radical is involved in the toxicity. Measurement of peroxide levels revealed that 3-HK caused intracellular accumulation of peroxide, which was largely attenuated by application of catalase. The peroxide accumulation and cell death caused by 1-10 microM 3-HK were also blocked by pretreatment with allopurinol or oxypurinol, suggesting that endogenous xanthine oxidase activity is involved in exacerbation of 3-HK neurotoxicity. Furthermore, NADPH diaphorase-containing neurons were spared from toxicity of these concentrations of 3-HK, a finding reminiscent of the pathological characteristics of several neurodegenerative disorders such as Huntington disease. These results suggest that 3-HK at pathologically relevant concentrations renders neuronal cells subject to oxidative stress leading to cell death, and therefore that this endogenous compound should be regarded as an important factor in pathogenesis of neurodegenerative disorders.
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Affiliation(s)
- S Okuda
- Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan
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29
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Zoref-Shani E, Bromberg Y, Lilling G, Gozes I, Brosh S, Sidi Y, Sperling O. Developmental changes in purine nucleotide metabolism in cultured rat astroglia. Int J Dev Neurosci 1995; 13:887-96. [PMID: 8770661 DOI: 10.1016/0736-5748(95)00054-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The present study was conducted in order to clarify the role of the glia in brain purine metabolism. This, in connection with the clarification of the etiology of the neurological manifestations associated with some of the inborn errors of purine metabolism in man. Purine nucleotide content, the capacity for de novo and salvage purine synthesis and the activity of several enzymes of purine nucleotide degradation, were assayed in primary cultures of rat astroglia in relation to culture age. The capacity of the intact cells to produce purine nucleotides de novo exhibited a marked decrease with the culture age, but the activity of hypoxanthine-guanine phosphoribosyltransferase (HGPRT), catalyzing salvage nucleotide synthesis, increased. Aging was also associated with a marked increase in the activity of the degradation enzymes AMP deaminase, purine nucleoside phosphorylase (PNP) and guanine deaminase (guanase). The activity of adenosine deaminase and of AMP-5'-nucleotidase, increased markedly during the first 17 days in culture, but decreased thereafter. The results indicate that purine nucleotide metabolism in the cultured astroglia is changing with aging to allow the cells to maintain their nucleotide pool by reutilization of preformed hypoxanthine, rather than by de-novo production of new purines. Aging is also associated with increased capacity for operation of the adenine nucleotide cycle, contributing to the homeostasis of adenine nucleotides and to the energy charge of the cells. In principle, the age-related alterations in purine metabolism in the astroglia resemble those occurring in the maturating neurons, except for the capacity to produce purines de novo, which exhibited inverse trends in the two tissues. However, in comparison to the neurons, the cultured astroglia possess the capacity for a more intensive metabolism of purine nucleotides.
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Affiliation(s)
- E Zoref-Shani
- Department of Clinical Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Israel
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30
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O'Neill RD, Lowry JP. On the significance of brain extracellular uric acid detected with in-vivo monitoring techniques: a review. Behav Brain Res 1995; 71:33-49. [PMID: 8747173 DOI: 10.1016/0166-4328(95)00035-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The concentration of uric acid [UA] in the extracellular fluid (ECF) estimated with in-vivo voltammetry and microdialysis data is compared for probes of different diameters from the day of implantation (acute) to several days (chronic) or even months after surgery. For small probes (diameter < 160 microns) the acute [UA] of ca. 5 microM decreased significantly to ca. 1 microM under chronic conditions. For larger probes (e.g., 320-microns diameter) the acute [UA] was also ca. 5 microM, but this value significantly increased to ca. 50 microM under chronic conditions. Associated with this difference in [UA], there were parallel differences in the extent of gliosis around the probes. These findings are discussed in terms of possible sources of extracellular UA and their implications for in-vivo monitoring techniques in behaving animals.
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Affiliation(s)
- R D O'Neill
- Department of Chemistry, University College Dublin, Belfield, Ireland.
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Abstract
Adenosine uptake in cultured astrocytes is dependent on various ions and energy metabolism. The Na(+)-gradient plays an important role, since nigericin, ouabain, amiloride and substitution of Na+ with choline inhibited adenosine uptake. The proton-gradient was of importance, since carbonylcyanide m-chlorophenylhydrozone (CCCP) and omeprazole also inhibited adenosine uptake. Furthermore, adenosine uptake was dependent on Cl- anion. Substitution of Cl- with isethionate, as well as DIDS or furosemide inhibited adenosine uptake. Adenosine uptake was also sensitive to Ca2+ gradient, removal of extracellular Ca2+ and calcimycin inhibited adenosine uptake. Adenosine uptake was not dependent on extracellular K+ and was not affected by valinomycin. Although, K(+)-channel openers (BRL 34195 and nicorandil) as well as the K(+)-channel antagonist, glyburide, inhibited adenosine uptake, the inhibitory effect of BRL 34915 was not antagonized by glyburide. Rotenone and 2,4-dinitrophenol also inhibited adenosine uptake. Ionic dependence and metabolic energy dependence of adenosine uptake suggest that uptake is primarily an active process.
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Affiliation(s)
- A S Bender
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City 84112
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32
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Phillis JW, Smith-Barbour M, Perkins LM, O'Regan MH. Indomethacin modulates ischemia-evoked release of glutamate and adenosine from the rat cerebral cortex. Brain Res 1994; 652:353-6. [PMID: 7953750 DOI: 10.1016/0006-8993(94)90248-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effects of indomethacin (10 mg/kg) on the release of the transmitter amino acids, glutamate, aspartate, GABA, and of the purines, adenosine and inosine, from the cerebral cortex was studied in a four-vessel occlusion rat model of cerebral ischemia/reperfusion. In comparison with the control group, indomethacin significantly attenuated the ischemia-evoked release of glutamate and aspartate, but not of GABA. Adenosine levels in the cortical superfusates were significantly elevated following indomethacin administration. As indomethacin is a potent inhibitor of adenosine uptake, these results suggest that, by blocking adenosine uptake, indomethacin could elevate extracellular adenosine levels and depress glutamate and aspartate efflux as a consequence of the activation of adenosine A1 receptors.
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Affiliation(s)
- J W Phillis
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201
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