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Cryan MT, Ross AE. Scalene Waveform for Codetection of Guanosine and Adenosine Using Fast-Scan Cyclic Voltammetry. Anal Chem 2019; 91:5987-5993. [DOI: 10.1021/acs.analchem.9b00450] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Michael T. Cryan
- Department of Chemistry, University of Cincinnati, 312 College Drive, 404 Crosley Tower, Cincinnati, Ohio 45221-0172, United States
| | - Ashley E. Ross
- Department of Chemistry, University of Cincinnati, 312 College Drive, 404 Crosley Tower, Cincinnati, Ohio 45221-0172, United States
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2
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Cryan MT, Ross AE. Subsecond detection of guanosine using fast-scan cyclic voltammetry. Analyst 2019; 144:249-257. [PMID: 30484441 DOI: 10.1039/c8an01547c] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Guanosine is an important neuromodulator and neuroprotector in the brain and is involved in many pathological conditions, including ischemia and neuroinflammation. Traditional methods to detect guanosine in the brain, like HPLC, offer low limits of detection and are robust; however, subsecond detection is not possible. Here, we present a method for detecting rapid fluctuations of guanosine concentration in real-time using fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes. The optimized waveform scanned from -0.4 V to 1.3 V and back at a rate of 400 V s-1 and application frequency of 10 Hz. Potential limits were chosen to increase selectivity of guanosine over the structurally similar interferent adenosine. Two oxidation peaks were detected with the optimized waveform: the primary oxidation reaction occurred at 1.3 V and the secondary oxidation at 0.8 V. Guanosine detection was stable over time with a limit of detection of 30 ± 10 nM, which permits its use to monitor low nanomolar fluctuations in the brain. To demonstrate the feasibility of the method for in-tissue detection, guanosine was exogenously applied and detected within live rat brain slices. This paper demonstrates the first characterization of guanosine using FSCV, and will be a valuable method for measuring signaling dynamics during guanosine neuromodulation and protection.
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Affiliation(s)
- Michael T Cryan
- University of Cincinnati, Department of Chemistry, 312 College Dr., 404 Crosley Tower, Cincinnati, OH 45221-0172, USA.
| | - Ashley E Ross
- University of Cincinnati, Department of Chemistry, 312 College Dr., 404 Crosley Tower, Cincinnati, OH 45221-0172, USA.
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van der Mierden S, Savelyev SA, IntHout J, de Vries RBM, Leenaars CHC. Intracerebral microdialysis of adenosine and adenosine monophosphate - a systematic review and meta-regression analysis of baseline concentrations. J Neurochem 2018; 147:58-70. [PMID: 30025168 PMCID: PMC6220825 DOI: 10.1111/jnc.14552] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/02/2018] [Accepted: 07/12/2018] [Indexed: 01/18/2023]
Abstract
Microdialysis is a method to study the extracellular space in vivo, based on the principle of diffusion. It can be used to measure various small molecules including the neuroregulator adenosine. Baseline levels of the compounds measured with microdialysis vary over studies. We systematically reviewed the literature to investigate the full range of reported baseline concentrations of adenosine and adenosine monophosphate in microdialysates. We performed a meta‐regression analysis to study the influence of flow rate, probe membrane surface area, species, brain area and anaesthesia versus freely behaving, on the adenosine concentration. Baseline adenosine concentrations in microdialysates ranged from 0.8 to 2100 nM. There was limited evidence on baseline adenosine monophosphate concentrations in microdialysates. Across studies, we found effects of flow rate and anaesthesia versus freely behaving on dialysate adenosine concentrations (p ≤ 0.001), but not of probe membrane surface, species, or brain area (p ≥ 0.14). With increasing flow rate, adenosine concentrations decreased. With anaesthesia, adenosine concentrations increased. The effect of other predictor variables on baseline adenosine concentrations, for example, post‐surgical recovery time, could not be analysed because of a lack of reported data. This study shows that meta‐regression can be used as an alternative to new animal experiments to answer research questions in the field of neurochemistry. However, current levels of reporting of primary studies are insufficient to reach the full potential of this approach; 63 out of 133 studies could not be included in the analysis because of insufficient reporting, and several potentially relevant factors had to be excluded from the analyses. The level of reporting of experimental detail needs to improve. ![]()
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Affiliation(s)
- Stevie van der Mierden
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.,Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Sergey A Savelyev
- Medical Biological Research & Development Centre 'Cytomed', St.-Petersburg, Russia
| | - Joanna IntHout
- Department for Health Evidence, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob B M de Vries
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Cathalijn H C Leenaars
- SYRCLE, Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.,Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany.,Department of Animals in Science and Society - Human-Animal Relationship, Utrecht University, Utrecht, The Netherlands
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Che X, Liu P, Wu C, Song W, An N, Yu L, Bai Y, Xing Z, Cai J, Wang X, Yang J. Potential role of the ecto-5'-nucleotidase in morphine-induced uridine release and neurobehavioral changes. Neuropharmacology 2018; 141:1-10. [PMID: 30071207 DOI: 10.1016/j.neuropharm.2018.07.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 07/24/2018] [Accepted: 07/29/2018] [Indexed: 12/21/2022]
Abstract
There is growing evidence that uridine may act as an endogenous neuromodulator with a potential signaling role in the central nervous system in addition to its function in pyrimidine metabolism. We previously found that acute morphine treatment significantly increased uridine release in the dorsal striatum of mice, indicating that uridine may contribute to morphine-induced neurobehavioral changes. In the present study, we analyzed the mechanism involved in morphine-induced uridine release and the role of uridine in morphine-induced neurobehavioral changes. Uridine release in the dorsal striatum of mice was assessed by in vivo microdialysis coupled with high performance liquid chromatography (HPLC) after morphine treatment. Western blotting and immunofluorescence were used to evaluate the expression of uridine-related proteins. Morphine-induced neurobehavioral changes were assessed by locomotor activity, behavioral sensitization and conditioned place preference (CPP) test. The expression of NT5E, an extracellular enzyme involved in formation of nucleosides, including uridine, was specifically knocked down in the dorsal striatum of mice using adeno-associated virus (AAV)-mediated short hairpin RNA (shRNA). The results indicated that both acute and chronic morphine administration significantly increased uridine release in the dorsal striatum, and this was associated with upregulation of NT5E but not other uridine-related proteins. Inhibition of NT5E with APCP or shRNA markedly inhibited morphine-induced uridine release in the dorsal striatum and related neurobehavioral changes, including hyperlocomotor activity, behavioral sensitization and CPP. Our data give a better understanding of the contribution of NT5E to morphine-induced uridine release and neurobehavioral changes, and identify NT5E as a potential target for treating morphine abuse.
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Affiliation(s)
- Xiaohang Che
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Ping Liu
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Chunfu Wu
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Wu Song
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Nina An
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Lisha Yu
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Yijun Bai
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Zheng Xing
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Jialing Cai
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Xiaomin Wang
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China
| | - Jingyu Yang
- Department of Pharmacology, Shenyang Pharmaceutical University, 110016, Shenyang, PR China.
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The Role of Adenosine Signaling in Headache: A Review. Brain Sci 2017; 7:brainsci7030030. [PMID: 28335379 PMCID: PMC5366829 DOI: 10.3390/brainsci7030030] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/05/2017] [Accepted: 03/07/2017] [Indexed: 12/18/2022] Open
Abstract
Migraine is the third most prevalent disease on the planet, yet our understanding of its mechanisms and pathophysiology is surprisingly incomplete. Recent studies have built upon decades of evidence that adenosine, a purine nucleoside that can act as a neuromodulator, is involved in pain transmission and sensitization. Clinical evidence and rodent studies have suggested that adenosine signaling also plays a critical role in migraine headache. This is further supported by the widespread use of caffeine, an adenosine receptor antagonist, in several headache treatments. In this review, we highlight evidence that supports the involvement of adenosine signaling in different forms of headache, headache triggers, and basic headache physiology. This evidence supports adenosine A2A receptors as a critical adenosine receptor subtype involved in headache pain. Adenosine A2A receptor signaling may contribute to headache via the modulation of intracellular Cyclic adenosine monophosphate (cAMP) production or 5' AMP-activated protein kinase (AMPK) activity in neurons and glia to affect glutamatergic synaptic transmission within the brainstem. This evidence supports the further study of adenosine signaling in headache and potentially illuminates it as a novel therapeutic target for migraine.
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de Oliveira ED, Schallenberger C, Böhmer AE, Hansel G, Fagundes AC, Milman M, Silva MDP, Oses JP, Porciúncula LO, Portela LV, Elisabetsky E, Souza DO, Schmidt AP. Mechanisms involved in the antinociception induced by spinal administration of inosine or guanine in mice. Eur J Pharmacol 2015; 772:71-82. [PMID: 26712379 DOI: 10.1016/j.ejphar.2015.12.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 12/17/2015] [Accepted: 12/18/2015] [Indexed: 11/27/2022]
Abstract
It is well known that adenine-based purines exert multiple effects on pain transmission. Recently, we have demonstrated that guanine-based purines may produce some antinociceptive effects against chemical and thermal pain in mice. The present study was designed to investigate the antinociceptive effects of intrathecal (i.t.) administration of inosine or guanine in mice. Additionally, investigation into the mechanisms of action of these purines, their general toxicity and measurements of CSF purine levels were performed. Animals received an i.t. injection of vehicle (30mN NaOH), inosine or guanine (up to 600nmol) and submitted to several pain models and behavioural paradigms. Guanine and inosine produced dose-dependent antinociceptive effects in the tail-flick, hot-plate, intraplantar (i.pl.) glutamate, i.pl. capsaicin and acetic acid pain models. Additionally, i.t. inosine inhibited the biting behaviour induced by spinal injection of capsaicin and i.t. guanine reduced the biting behaviour induced by spinal injection of glutamate or AMPA. Intrathecal administration of inosine (200nmol) induced an approximately 115-fold increase on CSF inosine levels. This study provides new evidence on the mechanism of action of extracellular guanine and inosine presenting antinociceptive effects following spinal administration. These effects seem to be related, at least partially, to the modulation of A1 adenosine receptors.
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Affiliation(s)
- Enderson D de Oliveira
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Cristhine Schallenberger
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Ana Elisa Böhmer
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | - Gisele Hansel
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Aécio C Fagundes
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Michael Milman
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Marcos D P Silva
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Jean P Oses
- Programa de Pós-graduação em Saúde e Comportamento, Centro de Ciências da Vida e da Saúde e Hospital Universitário São Francisco de Paula, Universidade Católica de Pelotas, Pelotas, RS, Brazil
| | - Lisiane O Porciúncula
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Luís V Portela
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Elaine Elisabetsky
- Department of Pharmacology, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Diogo O Souza
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - André P Schmidt
- Department of Biochemistry, Institute of Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Department of Anaesthesia and Perioperative Medicine, Hospital de Clínicas de Porto Alegre (HCPA), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Division of Anaesthesia, Department of Surgery, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.
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Yang YC, Hu CC, Lai YC. Non-additive modulation of synaptic transmission by serotonin, adenosine, and cholinergic modulators in the sensory thalamus. Front Cell Neurosci 2015; 9:60. [PMID: 25852468 PMCID: PMC4360759 DOI: 10.3389/fncel.2015.00060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/09/2015] [Indexed: 11/13/2022] Open
Abstract
The thalamus relays sensory information to the cortex. Oscillatory activities of the thalamocortical network are modulated by monoamines, acetylcholine, and adenosine, and could be the key features characteristic of different vigilance states. Although the thalamus is almost always subject to the actions of more than just one neuromodulators, reports on the modulatory effect of coexisting neuromodulators on thalamic synaptic transmission are unexpectedly scarce. We found that, if present alone, monoamine or adenosine decreases retinothalamic synaptic strength and short-term depression, whereas cholinergic modulators generally enhance postsynaptic response to presynaptic activity. However, coexistence of different modulators tends to produce non-additive effect, not predictable based on the action of individual modulators. Acetylcholine, acting via nicotinic receptors, can interact with either serotonin or adenosine to abolish most short-term synaptic depression. Moreover, the coexistence of adenosine and monoamine, with or without acetylcholine, results in robustly decreased synaptic strength and transforms short-term synaptic depression to facilitation. These findings are consistent with a view that acetylcholine is essential for an "enriched" sensory flow through the thalamus, and the flow is trimmed down by concomitant monoamine or adenosine (presumably for the wakefulness and rapid-eye movement, or REM, sleep states, respectively). In contrast, concomitant adenosine and monoamine would lead to a markedly "deprived" (and high-pass filtered) sensory flow, and thus the dramatic decrease of monoamine may constitute the basic demarcation between non-REM and REM sleep. The collective actions of different neuromodulators on thalamic synaptic transmission thus could be indispensable for the understanding of network responsiveness in different vigilance states.
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Affiliation(s)
- Ya-Chin Yang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University Tao-Yuan, Taiwan ; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University Tao-Yuan, Taiwan
| | - Chun-Chang Hu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University Tao-Yuan, Taiwan ; Department of Neurosurgery, Chang-Gung Memorial Hospital Linkou, Taiwan
| | - Yi-Chen Lai
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University Tao-Yuan, Taiwan
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Evidence for the existence of pyrimidinergic transmission in rat brain. Neuropharmacology 2014; 91:77-86. [PMID: 25541414 DOI: 10.1016/j.neuropharm.2014.12.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 12/06/2014] [Accepted: 12/11/2014] [Indexed: 11/21/2022]
Abstract
The uridine nucleotides uridine-5'-triphosphate (UTP) and uridine-5'-diphosphate (UDP) have previously been identified in media from cultured cells. However, no study to date has demonstrated their presence in brain extracellular fluid (ECF) obtained in vivo. Using a novel method, we now show that UTP and UDP, as well as uridine, are detectable in dialysates of striatal ECF obtained from freely-moving rats. Intraperitoneal (i.p.) administration of uridine or exposure of striatum to depolarizing concentrations of potassium chloride increases extracellular uridine, UTP and UDP, while tetrodotoxin (TTX) decreases their ECF levels. Uridine administration also enhances cholinergic neurotransmission which is accompanied by enhanced brain levels of diacylglycerol (DAG) and inositol trisphosphate (IP3) and blocked by suramin, but not by PPADS (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid) or MRS2578 suggesting a possible mediation of P2Y2 receptors activated by UTP. These observations suggest that uridine, UTP and UDP may function as pyrimidinergic neurotransmitters, and that enhancement of such neurotransmission underlies pharmacologic effects of exogenous uridine on the brain.
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Abstract
Evidences in the central nervous system are in favor that adenosine under basal conditions is released by a direct excitation-secretion modality. However, till now, there is no direct evidence that adenosine is contained in synaptic vesicles. Eight synaptic vesicle fractions were recovered on a discontinuous sucrose gradient after ultracentrifugation of the crude synaptosomal fraction (pellet P2) of rat brain. The adenosine content in each fraction was measured by high-performance liquid chromatography coupled to a fluorescence detector (minimum sensitivity 10 femtomoles). The immunoblot analysis, to detect synaptophysin, a molecular marker for the vesicle membrane, showed that fractions from 3 to 8 were rich in synaptophysin. The sum of adenosine found in fractions 3-8 was (mean ± SEM, n = 4) 3325.6 ± 94.6 pmol/mg of tissue protein. We proved that adenosine measured in synaptic vesicle fractions was not contaminated by cytosolic adenosine, as adenosine exogenously added to the P2 preferentially distributed in fractions 1 and 2 that are synaptophysin-free and did not contaminate the vesicle pellet P3. Data provide direct demonstration that adenosine is present in rat brain synaptic vesicle fractions. This information is consistent with the notion that adenosine is stored in synaptic vesicles and is released under normoxic physiological conditions by an excitation-secretion mechanism typical of neuronal cells.
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Kovács Z, Slézia A, Bali ZK, Kovács P, Dobolyi A, Szikra T, Hernádi I, Juhász G. Uridine modulates neuronal activity and inhibits spike-wave discharges of absence epileptic Long Evans and Wistar Albino Glaxo/Rijswijk rats. Brain Res Bull 2013; 97:16-23. [PMID: 23707857 DOI: 10.1016/j.brainresbull.2013.05.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 04/20/2013] [Accepted: 05/06/2013] [Indexed: 01/09/2023]
Abstract
Pharmacological and functional data suggest the existence of uridine (Urd) receptors in the central nervous system (CNS). In the present study, simultaneous extracellular single unit recording and microiontophoretic injection of the pyrimidine nucleoside Urd was used to provide evidence for the presence of Urd-sensitive neurons in the thalamus and the cerebral cortex of Long Evans rats. Twenty-two neurons in the thalamus (24% of recorded neurons) and 17 neurons in the cortex (55%) responded to the direct iontophoresis of Urd. The majority of Urd-sensitive neurons in the thalamus and cortex (82% and 59%, respectively) increased their firing rate in response to Urd. In contrary, adenosine (Ado) and uridine 5'-triphosphate (UTP) decreased the firing rate of all responding neurons in the thalamus, and the majority of responding neurons in the cortex (83% and 87%, respectively). Functional relevance of Urd-sensitive neurons was investigated in spontaneously epileptic freely moving Long Evans and Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. Intraperitoneal (i.p.) injection of 500mg/kg Urd decreased epileptic activity (210-270min after injection) in both rat strains. Intraperitoneal administration of 1000mg/kg Urd decreased the number of spike-wave discharges (SWDs) between 150-270min and 90-270min in Long Evans and WAG/Rij rats, respectively. The effect of Urd was long-lasting in both rat strains as the higher dose significantly decreased the number of SWDs even 24h after Urd injection. The present results suggest that Urd-sensitive neurons in the thalamus and the cerebral cortex may play a role in the antiepileptic action of Urd possibly via modulation of thalamocortical neuronal circuits.
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Affiliation(s)
- Zsolt Kovács
- Department of Zoology, University of West Hungary, Savaria Campus, Károlyi Gáspár tér 4, Szombathely 9700, Hungary.
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Song W, Wu CF, Liu P, Xiang RW, Wang F, Dong YX, Yang JY. Characterization of Basal and Morphine-Induced Uridine Release in the Striatum: An In Vivo Microdialysis Study in Mice. Neurochem Res 2012; 38:153-61. [DOI: 10.1007/s11064-012-0903-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/15/2012] [Accepted: 10/04/2012] [Indexed: 10/27/2022]
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Melani A, Corti F, Stephan H, Müller CE, Donati C, Bruni P, Vannucchi MG, Pedata F. Ecto-ATPase inhibition: ATP and adenosine release under physiological and ischemic in vivo conditions in the rat striatum. Exp Neurol 2011; 233:193-204. [PMID: 22001157 DOI: 10.1016/j.expneurol.2011.09.036] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 09/08/2011] [Accepted: 09/30/2011] [Indexed: 12/11/2022]
Abstract
In the central nervous system (CNS) ATP and adenosine act as transmitters and neuromodulators on their own receptors but it is still unknown which part of extracellular adenosine derives per se from cells and which part is formed from the hydrolysis of released ATP. In this study extracellular concentrations of adenosine and ATP from the rat striatum were estimated by the microdialysis technique under in vivo physiological conditions and after focal ischemia induced by medial cerebral artery occlusion. Under physiological conditions, adenosine and ATP concentrations were in the range of 130 nmol/L and 40 nmol/L, respectively. In the presence of the novel ecto-ATPase inhibitor, PV4 (100 nmol/L), the extracellular concentration of ATP increased 12-fold to ~360 nmol/L but the adenosine concentration was not altered. This demonstrates that, under physiological conditions, adenosine is not a product of extracellular ATP. In the first 4h after ischemia, adenosine increased to ~690 nmol/L and ATP to ~50 nmol/L. In the presence of PV4 the extracellular concentration of ATP was in the range of 450 nmol/L and a significant decrease in extracellular adenosine (to ~270 nmol/L) was measured. The contribution of extracellular ATP to extracellular adenosine was maximal in the first 20 min after ischemia onset. Furthermore we demonstrated, by immunoelectron microscopy, the presence of the concentrative nucleoside transporter CNT2 on plasma and vesicle membranes isolated from the rat striatum. These results are in favor that adenosine is transported in vesicles and is released in an excitation-secretion manner under in vivo physiological conditions. Early after ischemia, extracellular ATP is hydrolyzed by ecto-nucleotidases which significantly contribute to the increase in extracellular adenosine. To establish the contribution of extracellular ATP to adenosine might constitute the basis for devising a correct putative purinergic strategy aimed at protection from ischemic damage.
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Affiliation(s)
- Alessia Melani
- Department of Preclinical and Clinical Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy.
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Schmidt AP, Böhmer AE, Soares FA, Posso IP, Machado SB, Mendes FF, Portela LVC, Souza DO. Changes in purines concentration in the cerebrospinal fluid of patients experiencing pain: a case-control study. Neurosci Lett 2010; 474:69-73. [PMID: 20211694 DOI: 10.1016/j.neulet.2010.02.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 02/25/2010] [Accepted: 02/27/2010] [Indexed: 01/10/2023]
Abstract
This study analyzes the relationship between extracellular purines and pain perception in humans. Cerebrospinal fluid (CSF) levels of purines and their metabolites were compared between patients displaying acute and/or chronic pain syndromes and control subjects. The CSF levels of IMP, inosine, guanosine and uric acid were significantly increased in the chronic pain group and correlated with pain severity (P<0.05). Patients displaying both chronic and acute pain presented similar changes in the CSF purines concentration (P<0.05). However, in the acute pain group, only CSF inosine and uric acid levels were significantly increased (P<0.05). These findings suggest that purines, in special inosine, guanosine and uric acid, are associated with the spinal mechanisms underlying nociception.
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Affiliation(s)
- André P Schmidt
- Department of Biochemistry, ICBS, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
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Schmidt AP, Böhmer AE, Schallenberger C, Antunes C, Tavares RG, Wofchuk ST, Elisabetsky E, Souza DO. Mechanisms involved in the antinociception induced by systemic administration of guanosine in mice. Br J Pharmacol 2010; 159:1247-63. [PMID: 20132210 DOI: 10.1111/j.1476-5381.2009.00597.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE It is well known that adenine-based purines exert multiple effects on pain transmission. However, less attention has been given to the potential effects of guanine-based purines on pain transmission. The aim of this study was to investigate the effects of intraperitoneal (i.p.) and oral (p.o.) administration of guanosine on mice pain models. Additionally, investigation into the mechanisms of action of guanosine, its potential toxicity and cerebrospinal fluid (CSF) purine levels were also assessed. EXPERIMENTAL APPROACH Mice received an i.p. or p.o. administration of vehicle (0.1 mM NaOH) or guanosine (up to 240 mg x kg(-1)) and were evaluated in several pain models. KEY RESULTS Guanosine produced dose-dependent antinociceptive effects in the hot-plate, glutamate, capsaicin, formalin and acetic acid models, but it was ineffective in the tail-flick test. Additionally, guanosine produced a significant inhibition of biting behaviour induced by i.t. injection of glutamate, AMPA, kainate and trans-ACPD, but not against NMDA, substance P or capsaicin. The antinociceptive effects of guanosine were prevented by selective and non-selective adenosine receptor antagonists. Systemic administration of guanosine (120 mg x kg(-1)) induced an approximately sevenfold increase on CSF guanosine levels. Guanosine prevented the increase on spinal cord glutamate uptake induced by intraplantar capsaicin. CONCLUSIONS AND IMPLICATIONS This study provides new evidence on the mechanism of action of the antinociceptive effects after systemic administration of guanosine. These effects seem to be related to the modulation of adenosine A(1) and A(2A) receptors and non-NMDA glutamate receptors.
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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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Guanosine prevents thermal hyperalgesia in a rat model of peripheral mononeuropathy. THE JOURNAL OF PAIN 2009; 11:131-41. [PMID: 19734104 DOI: 10.1016/j.jpain.2009.06.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 05/29/2009] [Accepted: 06/17/2009] [Indexed: 12/16/2022]
Abstract
UNLABELLED It is well known that adenine-based purines exert multiple effects on pain transmission. Less attention has been given, however, to the antinociceptive effects of guanine-based purines. The aim of this study was to investigate the effects of intraperitoneal administration of guanosine on a rat model of peripheral mononeuropathy. Additionally, investigation of the mechanism of action of guanosine, its general toxicity and measurements of central nervous system purine levels were performed. Rats received an intraperitoneal administration of vehicle (0.1 mM NaOH) or guanosine (up to 120 mg.kg(-1)) in an acute or chronic regimen. Guanosine significantly reduced thermal hyperalgesia on the ipsilateral side of the sciatic nerve ligation. Additionally, guanosine prevented locomotor deficits and body weight loss induced by the mononeuropathy. Acute systemic administration of guanosine caused an approximately 11-fold increase on central nervous system guanosine levels, but this effect was not observed after chronic treatment. Chronic guanosine administration prevented the increase on cortical glutamate uptake but not the decrease in spinal cord glutamate uptake induced by the mononeuropathy. No significant general toxicity was observed after chronic exposure to guanosine. This study provides new evidence on the mechanism of action of guanine-based purines, with guanosine presenting antinociceptive effects against a chronic pain model. PERSPECTIVE This study provides a new role for guanosine: chronic pain modulation. Guanosine presents as a new target for future drug development and might be useful for treatment of neuropathic pain.
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17
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Wang TL, Wu CF, Yang JY, Wang F, Song W. Effect of morphine on brain uracil release in mouse striatum detected by microdialysis. Neurosci Lett 2009; 457:89-92. [PMID: 19429169 DOI: 10.1016/j.neulet.2009.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2009] [Revised: 03/01/2009] [Accepted: 03/03/2009] [Indexed: 10/21/2022]
Abstract
Effect of acute treatment of morphine is associated with neurotransmitter and neuromodulator changes in the brain. A possible relationship between pyrimidines and morphine has also been discussed. Uracil, a common and naturally occurring pyrimidine derivative which found in RNA, has been suggested to modulate many neurotransmitters or neuromodulators, especially in the mature central nervous system. The present study was performed to determine the effect of acutely intraperitoneal morphine treatment on the release of uracil in mouse striatum. The results showed that morphine significantly decreased the release of uracil at the dose of 10 and 20mg/kg in a dose dependent manner. Naloxone could reverse the morphine-induced reduction of uracil levels in mouse striatum, at the dose of 4 mg/kg, without affecting basal uracil release. The results suggest that the extracellular level of uracil in mouse striatum could be specifically regulated by the centrally acting drugs, such as morphine. However, the pharmacological implications of such regulation should be further evaluated.
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Affiliation(s)
- Tian Lin Wang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang 110016, PR China
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18
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Spinal mechanisms of antinociceptive action caused by guanosine in mice. Eur J Pharmacol 2009; 613:46-53. [DOI: 10.1016/j.ejphar.2009.04.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 04/01/2009] [Accepted: 04/08/2009] [Indexed: 11/20/2022]
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19
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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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20
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Antinociceptive effects of intracerebroventricular administration of guanine-based purines in mice: evidences for the mechanism of action. Brain Res 2008; 1234:50-8. [PMID: 18708036 DOI: 10.1016/j.brainres.2008.07.091] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 07/25/2008] [Accepted: 07/25/2008] [Indexed: 12/20/2022]
Abstract
It is well known that adenine-based purines exert multiple effects on pain transmission. However, less attention has been given to the potential effects of guanine-based purines (GBPs) on pain transmission. The aim of this study was to investigate the effects of intracerebroventricular (i.c.v.) guanosine and GMP on mice pain models. Mice received an i.c.v. injection of vehicle (saline or 10 muM NaOH), guanosine (5 to 400 nmol), or GMP (240 to 960 nmol). Additional groups were also pre-treated with i.c.v. injection of the A(1)/A(2A) antagonist caffeine (15 nmol), the non-selective opioid antagonist naloxone (12.5 nmol), or the 5'-nucleotidase inhibitor AOPCP (1 nmol). Measurements of CSF purine levels and cortical glutamate uptake were performed after treatments. Guanosine and GMP produced dose-dependent antinociceptive effects. Neither caffeine nor naloxone affected guanosine antinociception. Pre-treatment with AOPCP completely prevented GMP antinociception, indicating that conversion of GMP to guanosine is required for its antinociceptive effects. Intracerebroventricular administration of guanosine and GMP induced, respectively, a 180- and 1800-fold increase on CSF guanosine levels. Guanosine was able to prevent the decrease on cortical glutamate uptake induced by intraplantar capsaicin. This study provides new evidence on the mechanism of action of GBPs, with guanosine and GMP presenting antinociceptive effects in mice. This effect seems to be independent of adenosine and opioid receptors; it is, however, at least partially associated with modulation of the glutamatergic system by guanosine.
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21
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Schmidt AP, Lara DR, Souza DO. Proposal of a guanine-based purinergic system in the mammalian central nervous system. Pharmacol Ther 2007; 116:401-16. [PMID: 17884172 DOI: 10.1016/j.pharmthera.2007.07.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 07/30/2007] [Indexed: 01/06/2023]
Abstract
Guanine-based purines have been traditionally studied as modulators of intracellular processes, mainly G-protein activity. However, they also exert several extracellular effects not related to G proteins, including modulation of glutamatergic activity, trophic effects on neural cells, and behavioral effects. In this article, the putative roles of guanine-based purines on the nervous system are reviewed, and we propose a specific guanine-based purinergic system in addition to the well-characterized adenine-based purinergic system. Current evidence suggest that guanine-based purines modulate glutamatergic parameters, such as glutamate uptake by astrocytes and synaptic vesicles, seizures induced by glutamatergic agents, response to ischemia and excitotoxicity, and are able to affect learning, memory and anxiety. Additionally, guanine-based purines have important trophic functions affecting the development, structure, or maintenance of neural cells. Although studies addressing the mechanism of action (receptors and second messenger systems) of guanine-based purines are still insufficient, these findings point to the guanine-based purines (nucleotides and guanosine) as potential new targets for neuroprotection and neuromodulation.
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Affiliation(s)
- André P Schmidt
- Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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22
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Moretto MB, Arteni NS, Lavinsky D, Netto CA, Rocha JBT, Souza DO, Wofchuk S. Hypoxic-ischemic insult decreases glutamate uptake by hippocampal slices from neonatal rats: prevention by guanosine. Exp Neurol 2005; 195:400-6. [PMID: 16051218 DOI: 10.1016/j.expneurol.2005.06.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Revised: 04/15/2005] [Accepted: 06/04/2005] [Indexed: 11/27/2022]
Abstract
Brain injury secondary to hypoxic-ischemic disease is the predominant form of damage encountered in the perinatal period. The impact of neonatal hypoxia-ischemia (HI) in 7-day-old pups on the high-affinity [3H] glutamate uptake into hippocampal slices at different times after insult was examined. Immediately following, and 1 day after the insult there was no effect. But at 3 to 5 days after the HI insult, glutamate uptake into the hippocampus was markedly reduced; however, after 30 or 60 days the glutamate uptake into hippocampal slices returned to control levels. Also, this study demonstrated the effect of the nucleoside guanosine (Guo) on the [3H] glutamate uptake in neonatal HI injury, maintaining the [3H] glutamate uptake at control levels when injected before and after insult HI. We conclude that neonatal HI influences glutamate uptake a few days following insult, and that guanosine prevents this action.
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Affiliation(s)
- M B Moretto
- Departamento de Análises Clínicas e Toxicológicas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, RS, Brazil
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23
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Nicolaidis R, Bruno AN, Sarkis JJF, Souza DO. Increase of adenine nucleotide hydrolysis in rat hippocampal slices after seizures induced by quinolinic acid. Neurochem Res 2005; 30:385-90. [PMID: 16018583 DOI: 10.1007/s11064-005-2613-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Quinolinic acid (QUIN), an endogenous convulsant compound, overstimulates the glutamatergic system stimulating N-methyl-D-aspartate receptors, enhancing glutamate release and inhibiting glutamate uptake. Glutamate releases the neuroprotector adenosine, which in turn reduces glutamate release and depresses the neuronal activity. Additionally, adenine nucleotides are an important source of adenosine, by action of ecto-nucleotidases. Here we evaluated the adenine nucleotide hydrolysis in hippocampal slices of adult rats in different times after seizures induced by QUIN. After 45 min, there was an increase of ATP and ADP hydrolysis. After 5 h, there was an increase of ATP, ADP and AMP hydrolysis. After 12 h, there was an increase only of ATP hydrolysis. After 24 h, all hydrolysis returned to control levels. As slice preparations maintain tissue integrity, this study indicates, more than previously observed with synaptosomal preparations, that the extracellular production of the neuroprotector adenosine may be involved in brain responses to seizures.
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Affiliation(s)
- Rafael Nicolaidis
- Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
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24
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Frizzo ME, Schwalm FD, Frizzo JK, Soares FA, Souza DO. Guanosine Enhances Glutamate Transport Capacity in Brain Cortical Slices. Cell Mol Neurobiol 2005; 25:913-21. [PMID: 16133942 DOI: 10.1007/s10571-005-4939-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Accepted: 03/07/2005] [Indexed: 10/25/2022]
Abstract
1. The effect of guanosine on L-[3H] glutamate uptake was investigated in brain cortical slices within physio-pathological range of glutamate(1-1000 microM). In these conditions, glutamate uptake was significantly enhanced in slices treated with 100 microM guanosine only at 100 and 300 microM glutamate (44 and 52%, respectively). 2. Evaluation of kinetic parameters showed that guanosine affected significantly only uptake Vmax (23%). 3. The guanosine withdrawal did not abolish its significant effect on glutamate uptake when 100 or 300 microM glutamate were used (an increase of 66 and 35%, respectively). 4. These results support the hypothesis of a protective role for guanosine during excitotoxic conditions when glutamate levels are enhanced (e.g. brain ischemia and seizures), possibly by activating glutamate uptake. Moreover, our results may contribute to understand the antiexcitotoxic mechanism of guanosine on glutamate transport, giving new information concerning its mechanism of action.
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Affiliation(s)
- Marcos Emílio Frizzo
- Departamento de Bioquímica ICBS, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600 (Anexo), Porto Alegre, RS, 90035-003, Brazil.
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25
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Vinadé ER, Schmidt AP, Frizzo MES, Portela LV, Soares FA, Schwalm FD, Elisabetsky E, Izquierdo I, Souza DO. Effects of chronic administered guanosine on behavioral parameters and brain glutamate uptake in rats. J Neurosci Res 2005; 79:248-53. [PMID: 15558762 DOI: 10.1002/jnr.20327] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Oral and intraperitoneal administration of the nucleoside guanosine have been shown to prevent quinolinic acid- (QA) and alpha-dendrotoxin-induced seizures, impair memory, and impair anxiety in rats and mice. We investigated the effect of 2-weeks ad lib orally administered guanosine (0.5 mg/ml) on seizures induced by QA, inhibitory avoidance memory, and locomotor performance in rats. We also studied the mechanism of action of guanosine through the measurement of its concentration in the cerebrospinal fluid (CSF) and its effect on glutamate uptake in cortical slices of rats. QA produced seizures in 85% of rats, an effect partially prevented by guanosine (53% of seizures; P = 0.0208). Guanosine also impaired retention on the inhibitory avoidance task (P = 0.0278) and decreased locomotor activity on the open field test (P = 0.0101). The CSF guanosine concentration increased twofold in the treated group compared to that in the vehicle group (P = 0.0178). Additionally, QA promoted a 30% decrease in glutamate uptake as compared to that with intracerebroventricular saline administration, an effect prevented by guanosine in animals protected against QA-induced seizures. Altogether, these findings suggest a potential role of guanosine for treating diseases involving glutamatergic excitotoxicity such as epilepsy. These effects seem to be related to modulation of glutamate uptake.
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Affiliation(s)
- Elsa R Vinadé
- Department of Biochemistry, ICBS, Federal University of Rio Grande do Sul, Avenida Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
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26
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Peng L, Huang R, Yu ACH, Fung KY, Rathbone MP, Hertz L. Nucleoside transporter expression and function in cultured mouse astrocytes. Glia 2005; 52:25-35. [PMID: 15892125 DOI: 10.1002/glia.20216] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Uptake of purine and pyrimidine nucleosides in astrocytes is important for several reasons: (1) uptake of nucleosides contributes to nucleic acid synthesis; (2) astrocytes synthesize AMP, ADP, and ATP from adenosine and GTP from guanosine; and (3) adenosine and guanosine function as neuromodulators, whose effects are partly terminated by cellular uptake. It has previously been shown that adenosine is rapidly accumulated by active uptake in astrocytes (Hertz and Matz, Neurochem Res 14:755-760, 1989), but the ratio between active uptake and metabolism-driven uptake of adenosine is unknown, as are uptake characteristics for guanosine. The present study therefore aims at providing detailed information of nucleoside transport and transporters in primary cultures of mouse astrocytes. Reverse transcription-polymerase chain reaction identified the two equilibrative nucleoside transporters, ENT1 and ENT2, together with the concentrative nucleoside transporter CNT2, whereas CNT3 was absent, and CNT1 expression could not be investigated. Uptake studies of tritiated thymidine, formycin B, guanosine, and adenosine (3-s uptakes at 1-4 degrees C to study diffusional uptake and 1-60-min uptakes at 37 degrees C to study concentrative uptake) demonstrated a fast diffusional uptake of all four nucleosides, a small, Na(+)-independent and probably metabolism-driven uptake of thymidine (consistent with DNA synthesis), larger metabolism-driven uptakes of guanosine (consistent with synthesis of DNA, RNA, and GTP) and especially of adenosine (consistent with rapid nucleotide synthesis), and Na(+)-dependent uptakes of adenosine (consistent with its concentrative uptake) and guanosine, rendering neuromodulator uptake independent of nucleoside metabolism. Astrocytes are accordingly well suited for both intense nucleoside metabolism and metabolism-independent uptake to terminate neuromodulator effects of adenosine and guanosine.
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Affiliation(s)
- Liang Peng
- Hong Kong DNA Chips, Ltd., Kowloon, Hong Kong, China
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27
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Slézia A, Kékesi AK, Szikra T, Papp AM, Nagy K, Szente M, Maglóczky Z, Freund TF, Juhász G. Uridine release during aminopyridine-induced epilepsy. Neurobiol Dis 2004; 16:490-9. [PMID: 15262260 DOI: 10.1016/j.nbd.2004.02.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2002] [Revised: 01/23/2004] [Accepted: 02/25/2004] [Indexed: 12/01/2022] Open
Abstract
Uridine, like adenosine, is released under sustained depolarization and it can inhibit hippocampal neuronal activity, suggesting that uridine may be released during seizures and can be involved in epileptic mechanisms. In an in vivo microdialysis study, we measured the extracellular changes of nucleoside and amino acid levels and recorded cortical EEG during 3-aminopyridine-induced epilepsy. Applying silver impregnation and immunohistochemistry, we examined the degree of hippocampal cell loss. We found that extracellular concentration of uridine, adenosine, inosine, and glutamate increased significantly, while glutamine level decreased during seizures. The release of uridine correlated with seizure activity. Systemic and local uridine application was ineffective. The number of parvalbumin- and calretinin-containing interneurons of dorsal hippocampi decreased. We conclude that uridine is released during epileptic activity, and suggest that as a neuromodulator, uridine may contribute to epilepsy-related neuronal activity changes, but uridine analogues having slower turnover would be needed for further investigation of physiological role of uridine.
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Affiliation(s)
- A Slézia
- Research Group of Neurobiology of the Hungarian Academy of Sciences, Eötvös Loránd University, H-1117 Budapest, Hungary
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28
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Vinadé ER, Schmidt AP, Frizzo MES, Izquierdo I, Elisabetsky E, Souza DO. Chronically administered guanosine is anticonvulsant, amnesic and anxiolytic in mice. Brain Res 2003; 977:97-102. [PMID: 12788518 DOI: 10.1016/s0006-8993(03)02769-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acute administration of intraperitoneal and oral guanosine has been shown to prevent quinolinic acid and alpha-dendrotoxin-induced seizures in rats and mice. In this study, we investigated the effects of 2 weeks ad libitum consumption of guanosine (0.5 mg/ml) added to mice water supply on seizures and lethality induced by the alpha-dendrotoxin, hole-board behavior, inhibitory avoidance task, locomotor activity, motor coordination, rectal temperature, body weight, and water and food consumption. Guanosine prevented seizures in 40% and death in 50% on mice treated with i.c.v. alpha-dendrotoxin; it also impaired inhibitory avoidance memory and increased head-dipping behavior and locomotor activity on the hole-board test. Guanosine consumption did not alter any of the other parameters evaluated. The anticonvulsant, amnesic, and anxyolytic-like effects may be associated with the ability of guanosine in modulating the glutamatergic excitatory system. Adding to previously reported data, these findings suggest a potential role for chronic guanosine in the management of diseases associated with glutamatergic excitotoxicity, including epilepsy and anxiety.
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Affiliation(s)
- Elsa Regina Vinadé
- Department of Biochemistry, ICBS, Federal University of Rio Grande do Sul, Avenida Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
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29
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Frizzo MEDS, Antunes Soares FA, Dall'Onder LP, Lara DR, Swanson RA, Souza DO. Extracellular conversion of guanine-based purines to guanosine specifically enhances astrocyte glutamate uptake. Brain Res 2003; 972:84-9. [PMID: 12711081 DOI: 10.1016/s0006-8993(03)02506-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Guanosine (GUO) has been shown to stimulate glutamate uptake in primary astrocyte cultures. The purpose of this study was to determine the effect and specificity of guanine- or adenine-based purines on glutamate and GABA uptake in cultured astrocytes. Stimulatory effect on glutamate uptake was observed with GUO, GMP or GTP. Simultaneous exposure with these guanine-based purines did not show an additive effect. We also investigated a possible interconversion of guanine-based purines during incubation time. Action by GTP was excluded since the hydrolysis resistant GTP analog, GMP-PNP did not stimulate glutamate uptake. Addition of an ecto-5'-nucleotidase inhibitor abolished GMP-stimulatory effect on glutamate uptake, without affecting GUO action. Taken together, these results suggest that GUO is the guanine-based purines responsible for glutamate uptake activation. In addition, the stimulatory effect on glutamate uptake was not observed with adenine-based purines. Moreover, GABA uptake was not activated by GUO. These results point to specificity in the interaction between GUO and the astrocyte glutamate uptake system.
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Affiliation(s)
- Marcos Emílio dos Santos Frizzo
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600 (Anexo), 90035-003 Porto Alegre, RS, Brazil.
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30
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Gottfried C, Tramontina F, Gonçalves D, Gonçalves CA, Moriguchi E, Dias RD, Wofchuk ST, Souza DO. Glutamate uptake in cultured astrocytes depends on age: a study about the effect of guanosine and the sensitivity to oxidative stress induced by H(2)O(2). Mech Ageing Dev 2002; 123:1333-40. [PMID: 12297336 DOI: 10.1016/s0047-6374(02)00069-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Relatively few studies have been conducted to investigate the relationship between glutamate and development and/or aging. Rat cortical astrocyte cultures were used as a model to investigate glutamate uptake during development. The immunocontent of the markers glial fibrillary acidic protein (GFAP) and S100B increased, while basal secretion of S100B decreased, in astrocytes from 10 to 40 days in vitro (DIV). Basal glutamate uptake increased with age. Exposure to hydrogen peroxide decreased glutamate uptake more potently at 40 than 10 DIV. Moreover, 40 DIV astrocytes showed earlier loss of integrity (at 6 h) than 10 DIV astrocytes (at 24 h) after H(2)O(2) exposure. Addition of guanosine stimulated glutamate uptake only in 10 DIV astrocytes. The present work shows that mature astrocytes in culture present some neurochemical alterations also observed in astrocytes of aged animals. These results can contribute to the understanding of some consequences of the excitotoxicity and oxidative stress during brain aging.
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Affiliation(s)
- Carmem Gottfried
- Departamento de Ciências Fisiológicas, Faculdade de Biociências, Pontifi;cia Universidade Católica do Rio Grande do Sul, PUCRS, RS, Porto Alegre, Brazil.
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31
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Frizzo MEDS, Lara DR, Prokopiuk ADS, Vargas CR, Salbego CG, Wajner M, Souza DO. Guanosine enhances glutamate uptake in brain cortical slices at normal and excitotoxic conditions. Cell Mol Neurobiol 2002; 22:353-63. [PMID: 12469876 DOI: 10.1023/a:1020728203682] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
1. The effect of guanosine on L-[2,3-3H]glutamate uptake was investigated in brain cortical slices under normal or oxygen-glucose deprivation (OGD) conditions. 2. In slices exposed to physiological conditions, guanosine (1-100 microM) stimulated glutamate uptake (up to 100%) in a concentration-dependent manner when a high (100 microM) but not a low (1 microM) concentration of glutamate was used. 3. In slices submitted to OGD, guanosine 1 and 100 microM also increased 100 microM glutamate uptake (38 and 70%, respectively). 4. The increasing of glutamate and taurine released to the incubation medium in cortical slices submitted to OGD were significantly attenuated by the presence of guanosine in the incubation medium. 5. Guanosine prevented the increase in propidium iodide incorporation into cortical slices induced by OGD, indicating a protective role against ischemic injury. 6. These results support the hypothesis of a protective role for guanosine during brain ischemia, possibly by activating glutamate uptake into neural cells.
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32
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Nyitrai G, Kékesi KA, Szilágyi N, Papp A, Juhász G, Kardos J. Neurotoxicity of lindane and picrotoxin: neurochemical and electrophysiological correlates in the rat hippocampus in vivo. Neurochem Res 2002; 27:139-45. [PMID: 11926266 DOI: 10.1023/a:1014819125873] [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] [Indexed: 11/12/2022]
Abstract
In the present study, we compared in vivo changes of extracellular amino acid levels and nucleotide derivatives to a single ip dose of lindane (10-60 mg/kg) and picrotoxin (5 mg/kg) in the hippocampus of halothane anaesthetized rat by microdialysis-coupled HPLC analysis. Brain activity was monitored by EEG. The effects of lindane and picrotoxin on EEG pattern of rats as well as on hippocampal amino acid and nucleotide status were studied in 0-50 min, 50-100 min and 100-150 min periods post-dosing. Significant decreases in Glu and Asp were found after picrotoxin treatment. After 50-100 min post-dosing, hippocampal hypoxanthine and inosine levels increased to both lindane (10 mg/kg) and picrotoxin whereas xanthine and uridine levels increased to picrotoxin, only. Lindane elicited a dose-dependent occurrence of negative spikes accompanied with rhythmic activity at 4-5 Hz. The picrotoxin-induced 4-5 Hz activity did not display negative sharp waves and was accompanied by 10 Hz oscillations.
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Affiliation(s)
- Gabriella Nyitrai
- Department of Neurochemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest
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Latini S, Pedata F. Adenosine in the central nervous system: release mechanisms and extracellular concentrations. J Neurochem 2001; 79:463-84. [PMID: 11701750 DOI: 10.1046/j.1471-4159.2001.00607.x] [Citation(s) in RCA: 549] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Adenosine has several functions within the CNS that involve an inhibitory tone of neurotransmission and neuroprotective actions in pathological conditions. The understanding of adenosine production and release in the brain is therefore of fundamental importance and has been extensively studied. Conflicting results are often obtained regarding the cellular source of adenosine, the stimulus that induces release and the mechanism for release, in relation to different experimental approaches used to study adenosine production and release. A neuronal origin of adenosine has been demonstrated through electrophysiological approaches showing that neurones can release significant quantities of adenosine, sufficient to activate adenosine receptors and to modulate synaptic functions. Specific actions of adenosine are mediated by different receptor subtypes (A(1), A(2A), A(2B) and A(3)), which are activated by various ranges of adenosine concentrations. Another important issue is the measurement of adenosine concentrations in the extracellular fluid under different conditions in order to know the degree of receptor stimulation and understand adenosine central actions. For this purpose, several experimental approaches have been used both in vivo and in vitro, which provide an estimation of basal adenosine levels in the range of 50-200 nM. The purpose of this review is to describe pathways of adenosine production and metabolism, and to summarize characteristics of adenosine release in the brain in response to different stimuli. Finally, studies performed to evaluate adenosine concentrations under physiological and hypoxic/ischemic conditions will be described to evaluate the degree of adenosine receptor activation.
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Affiliation(s)
- S Latini
- Department of Preclinical and Clinical Pharmacology, University of Florence, Florence, Italy
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34
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Lara DR, Schmidt AP, Frizzo ME, Burgos JS, Ramírez G, Souza DO. Effect of orally administered guanosine on seizures and death induced by glutamatergic agents. Brain Res 2001; 912:176-80. [PMID: 11532434 DOI: 10.1016/s0006-8993(01)02734-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Intraperitoneal guanosine has been shown to prevent quinolinic acid-induced seizures in mice. In this study, we investigated the effect of orally administered guanosine on seizures induced by the glutamate agonists quinolinic acid and kainate, and the endogenous glutamate releaser alpha-dendrotoxin. Guanosine (7.5 mg/kg, per os), administered 75 min in advance, prevented 70% of seizures induced by i.c.v. quinolinic acid, being as efficient as the NMDA channel blocker MK-801 administered intraperitoneally. Guanosine was ineffective against kainate-induced seizures, but significantly reversed the potentiation of seizures and death caused by the concomitant injection of MK-801. Guanosine also significantly prevented seizures and death induced by i.c.v. alpha-dendrotoxin, whereas MK-801 and phenobarbital only prevented death. Altogether, our findings underscore the therapeutic potential of oral administration of guanosine for treating diseases involving glutamatergic excitotoxicity, including epilepsy.
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Affiliation(s)
- D R Lara
- Department of Biochemistry, ICBS, Federal University of Rio Grande do Sul, Avenida Ramiro Barcelos, 2600-Anexo, CEP 90035-003, RS, Porto Alegre, Brazil
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35
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Chen Y, Rathbone MP, Hertz L. Guanosine-induced increase in free cytosolic calcium concentration in mouse astrocytes in primary cultures: does it act on an A3 adenosine receptor? J Neurosci Res 2001; 65:184-9. [PMID: 11438987 DOI: 10.1002/jnr.1141] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Purinergic receptors play an important role in the regulation of free cytosolic calcium concentration ([Ca(2+)](i)) in astrocytes. In the present study, 10 microM adenosine caused an increase in [Ca(2+)](i) in 85% of the cultures studied, i.e., primary cultures of mouse astrocytes, differentiated by culturing in the presence of dibutyryl cyclic AMP. Antagonist sensitivity and rapid desensitization suggested that it did so by acting on A3 receptors. Another biologically important purine, guanosine, also caused an increase in astrocytic [Ca(2+)](i) (at concentrations of 0.1-100 microM). Although this response did not show the same rapid desensitization as the response to adenosine, it may also have been exerted on an A3 receptor. It supports this idea that inosine also caused an increase in [Ca(2+)](i), because inosine is known to activate A3 receptors in mast cells and structurally is even more closely related to guanosine than is adenosine.
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Affiliation(s)
- Y Chen
- Department of Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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36
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Frizzo ME, Lara DR, Dahm KC, Prokopiuk AS, Swanson RA, Souza DO. Activation of glutamate uptake by guanosine in primary astrocyte cultures. Neuroreport 2001; 12:879-81. [PMID: 11277601 DOI: 10.1097/00001756-200103260-00051] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Guanine-based purines have been shown to modulate the effects of glutamate, which is essential for brain function and mediates excitotoxicity. In the search for a mechanism involving the interaction between purine nucleoside guanosine and glutamate, we found that guanosine dose-dependently, significantly (63%) and potently (EC50 =2.47 microM) enhanced glutamate uptake in cultured astrocytes. This effect was not inhibited by the blocker of nucleoside transporter dipyridamole nor by the adenosine antagonist theophylline, suggesting an extracellular site of action without the involvement of adenosine receptors. These results indicate a regulatory role of guanosine on extracellular levels of glutamate, possibly contributing for protecting neural cells against glutamate-induced excitotoxicity.
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Affiliation(s)
- M E Frizzo
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil
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