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de Freitas Souza C, Baldissera MD, Barroso D, de Lima MCM, Baldisserotto B, Val AL. Involvement of purinergic system and electron transport chain in two species of cichlids from the Amazon basin exposed to hypoxia. Comp Biochem Physiol A Mol Integr Physiol 2021; 255:110918. [DOI: 10.1016/j.cbpa.2021.110918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 01/12/2023]
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2
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Doná F, Conceição IM, Ulrich H, Ribeiro EB, Freitas TA, Nencioni ALA, da Silva Fernandes MJ. Variations of ATP and its metabolites in the hippocampus of rats subjected to pilocarpine-induced temporal lobe epilepsy. Purinergic Signal 2016; 12:295-302. [PMID: 26939579 DOI: 10.1007/s11302-016-9504-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 02/16/2016] [Indexed: 12/30/2022] Open
Abstract
Although purinergic receptor activity has lately been associated with epilepsy, little is known about the exact role of purines in epileptogenesis. We have used a rat model of temporal lobe epilepsy induced by pilocarpine to study the dynamics of purine metabolism in the hippocampus during different times of status epilepticus (SE) and the chronic phase. Concentrations of adenosine 5'-triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), and adenosine in normal and epileptic rat hippocampus were determined by microdialysis in combination with high-performance liquid chromatography (HPLC). Extracellular ATP concentrations did not vary along 4 h of SE onset. However, AMP concentration was elevated during the second hour, whereas ADP and adenosine concentrations augmented during the third and fourth hour following SE. During chronic phase, extracellular ATP, ADP, AMP, and adenosine concentrations decreased, although these levels again increased significantly during spontaneous seizures. These results suggest that the increased turnover of ATP during the acute period is a compensatory mechanism able to reduce the excitatory role of ATP. Increased adenosine levels following 4 h of SE may contribute to block seizures. On the other hand, the reduction of purine levels in the hippocampus of chronic epileptic rats may result from metabolic changes and be part of the mechanisms involved in the onset of spontaneous seizures. This work provides further insights into purinergic signaling during establishment and chronic phase of epilepsy.
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Affiliation(s)
- Flávia Doná
- Departamento de Neurologia e Neurocirurgia, Disciplina de Neurociências, Universidade Federal de São Paulo, UNIFESP, Rua Pedro de Toledo, 669 - 2° andar, CEP 04039-032, São Paulo, Brazil.,Laboratório de Reabilitação do Equilíbrio Corporal e Inclusão Social, Universidade Anhanguera de São Paulo (UNIAN), São Paulo, Brazil
| | | | - Henning Ulrich
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Eliane Beraldi Ribeiro
- Departamento Fisiologia, Disciplina de Neurofisiologia e Fisiologia Endócrina, UNIFESP, São Paulo, Brazil
| | | | | | - Maria José da Silva Fernandes
- Departamento de Neurologia e Neurocirurgia, Disciplina de Neurociências, Universidade Federal de São Paulo, UNIFESP, Rua Pedro de Toledo, 669 - 2° andar, CEP 04039-032, São Paulo, Brazil.
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Pedata F, Dettori I, Coppi E, Melani A, Fusco I, Corradetti R, Pugliese AM. Purinergic signalling in brain ischemia. Neuropharmacology 2015; 104:105-30. [PMID: 26581499 DOI: 10.1016/j.neuropharm.2015.11.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 11/04/2015] [Accepted: 11/06/2015] [Indexed: 12/18/2022]
Abstract
Ischemia is a multifactorial pathology characterized by different events evolving in the time. After ischemia a primary damage due to the early massive increase of extracellular glutamate is followed by activation of resident immune cells, i.e microglia, and production or activation of inflammation mediators. Protracted neuroinflammation is now recognized as the predominant mechanism of secondary brain injury progression. Extracellular concentrations of ATP and adenosine in the brain increase dramatically during ischemia in concentrations able to stimulate their respective specific P2 and P1 receptors. Both ATP P2 and adenosine P1 receptor subtypes exert important roles in ischemia. Although adenosine exerts a clear neuroprotective effect through A1 receptors during ischemia, the use of selective A1 agonists is hampered by undesirable peripheral effects. Evidence up to now in literature indicate that A2A receptor antagonists provide protection centrally by reducing excitotoxicity, while agonists at A2A (and possibly also A2B) and A3 receptors provide protection by controlling massive infiltration and neuroinflammation in the hours and days after brain ischemia. Among P2X receptors most evidence indicate that P2X7 receptor contribute to the damage induced by the ischemic insult due to intracellular Ca(2+) loading in central cells and facilitation of glutamate release. Antagonism of P2X7 receptors might represent a new treatment to attenuate brain damage and to promote proliferation and maturation of brain immature resident cells that can promote tissue repair following cerebral ischemia. Among P2Y receptors, antagonists of P2Y12 receptors are of value because of their antiplatelet activity and possibly because of additional anti-inflammatory effects. Moreover strategies that modify adenosine or ATP concentrations at injury sites might be of value to limit damage after ischemia. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Felicita Pedata
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy.
| | - Ilaria Dettori
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Elisabetta Coppi
- Department of Health Sciences, University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Alessia Melani
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Irene Fusco
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Anna Maria Pugliese
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
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Spanevello R, Mazzanti CM, Schmatz R, Bagatini M, Stefanello N, Correa M, Kaizer R, Maldonado P, Mazzanti A, Graça DL, Martins TB, Danesi C, Morsch VM, Schetinger MRC. Effect of vitamin E on ectonucleotidase activities in synaptosomes and platelets and parameters of oxidative stress in rats experimentally demyelinated. Brain Res Bull 2009; 80:45-51. [DOI: 10.1016/j.brainresbull.2009.05.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 04/24/2009] [Accepted: 05/13/2009] [Indexed: 02/05/2023]
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Delwing D, Delwing D, Sarkis JJF, Wyse ATS. Proline induces alterations on nucleotide hydrolysis in synaptosomes from cerebral cortex of rats. Brain Res 2007; 1149:210-5. [PMID: 17407768 DOI: 10.1016/j.brainres.2007.02.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 02/19/2007] [Accepted: 02/21/2007] [Indexed: 10/23/2022]
Abstract
In the present study we investigated the in vivo (acute and chronic) and in vitro effects of proline on NTPDase and 5'-nucleotidase activities in synaptosomes obtained from cerebral cortex of rats. For acute administration, 29-day-old rats received one subcutaneous injection of proline (18.2 micromol/g body weight) or an equivalent volume of 0.9% saline solution (control) and were killed 1 h later. For chronic treatment, buffered proline was injected subcutaneously into rats twice a day at 10 h intervals from the 6th to the 28th day of age. Rats were killed 12 h after the last injection. Results showed that acute and chronic proline administration provoked a reduction (25%) of ATP hydrolysis, but did not alter ADP and AMP hydrolysis. We also verified the in vitro effect of proline (3.0 microM-1.0 mM) on nucleotide hydrolysis in synaptosomes from cerebral cortex of rats. In contrast to the in vivo studies, it was not observed any statistically significant alteration on ATP, ADP and AMP hydrolysis. In conclusion, according to our results, it seems reasonable to postulate that proline administration alters the hydrolysis of ATP and probably affects the responses mediated by adenine nucleotides in the central nervous system of proline treated rats.
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Affiliation(s)
- Daniela Delwing
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, Brazil
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6
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Schetinger MRC, Morsch VM, Bonan CD, Wyse ATS. NTPDase and 5'-nucleotidase activities in physiological and disease conditions: new perspectives for human health. Biofactors 2007; 31:77-98. [PMID: 18806312 DOI: 10.1002/biof.5520310205] [Citation(s) in RCA: 160] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Extracellular nucleotides and nucleosides act as signaling molecules involved in a wide spectrum of biological effects. Their levels are controlled by a complex cell surface-located group of enzymes called ectonucleotidases. There are four major families of ectonucleotidases, nucleoside triphosphate diphosphohydrolases (NTPDases/CD39), ectonucleotide pyrophosphatase/phosphodiesterases (E-NPPs), alkaline phosphatases and ecto-5'-nucleotidase. In the last few years, substantial progress has been made toward the molecular identification of members of the ectonucleotidase families and their enzyme structures and functions. In this review, there is an emphasis on the involvement of NTPDase and 5'-nucleotidase activities in disease processes in several tissues and cell types. Brief background information is given about the general characteristics of these enzymes, followed by a discussion of their roles in thromboregulatory events in diabetes, hypertension, hypercholesterolemia and cancer, as well as in pathological conditions where platelets are less responsive, such as in chronic renal failure. In addition, immunomodulation and cell-cell interactions involving these enzymes are considered, as well as ATP and ADP hydrolysis under different clinical conditions related with alterations in the immune system, such as acute lymphoblastic leukemia (ALL), B-chronic lymphocytic leukemia (B-CLL) and infections associated with human immunodeficiency virus (HIV). Finally, changes in ATP, ADP and AMP hydrolysis induced by inborn errors of metabolism, seizures and epilepsy are discussed in order to highlight the importance of these enzymes in the control of neuronal activity in pathological conditions. Despite advances made toward understanding the molecular structure of ectonucleotidases, much more investigation will be necessary to entirely grasp their role in physiological and pathological conditions.
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Affiliation(s)
- Maria Rosa C Schetinger
- Laboratório de Enzimologia Toxicológica, Departamento de Química, CCNE, Universidade Federal de Santa Maria, Avenida Roraima, no 1000, Cidade Universitária, Bairro Camobi, Santa Maria-RS, 97105-900, Brazil.
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Robson SC, Sévigny J, Zimmermann H. The E-NTPDase family of ectonucleotidases: Structure function relationships and pathophysiological significance. Purinergic Signal 2006; 2:409-30. [PMID: 18404480 PMCID: PMC2254478 DOI: 10.1007/s11302-006-9003-5] [Citation(s) in RCA: 712] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 01/23/2006] [Indexed: 12/17/2022] Open
Abstract
Ectonucleotidases are ectoenzymes that hydrolyze extracellular nucleotides to the respective nucleosides. Within the past decade, ectonucleotidases belonging to several enzyme families have been discovered, cloned and characterized. In this article, we specifically address the cell surface-located members of the ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase/CD39) family (NTPDase1,2,3, and 8). The molecular identification of individual NTPDase subtypes, genetic engineering, mutational analyses, and the generation of subtype-specific antibodies have resulted in considerable insights into enzyme structure and function. These advances also allow definition of physiological and patho-physiological implications of NTPDases in a considerable variety of tissues. Biological actions of NTPDases are a consequence (at least in part) of the regulated phosphohydrolytic activity on extracellular nucleotides and consequent effects on P2-receptor signaling. It further appears that the spatial and temporal expression of NTPDases by various cell types within the vasculature, the nervous tissues and other tissues impacts on several patho-physiological processes. Examples include acute effects on cellular metabolism, adhesion, activation and migration with other protracted impacts upon developmental responses, inclusive of cellular proliferation, differentiation and apoptosis, as seen with atherosclerosis, degenerative neurological diseases and immune rejection of transplanted organs and cells. Future clinical applications are expected to involve the development of new therapeutic strategies for transplantation and various inflammatory cardiovascular, gastrointestinal and neurological diseases.
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Affiliation(s)
- Simon C. Robson
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts USA
| | - Jean Sévigny
- Centre de Recherche en Rhumatologie et Immunologie, Université Laval, Québec, Québec Canada
| | - Herbert Zimmermann
- Institut fuer Zellbiologie und Neurowissenschaft, Biozentrum der J.W. Goethe-Universitaet, Marie-Curie-Str. 9, D-60439 Frankfurt am Main, Germany
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8
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Wilot LC, Da Silva RS, Ferreira OJ, Bonan CD, Sarkis JJF, Rocha E, Battastini AMO. Chronic treatment with lithium increases the ecto-nucleotidase activities in rat hippocampal synatosomes. Neurosci Lett 2004; 368:167-70. [PMID: 15351442 DOI: 10.1016/j.neulet.2004.07.002] [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: 04/05/2004] [Revised: 06/29/2004] [Accepted: 07/02/2004] [Indexed: 10/26/2022]
Abstract
Lithium is a mood-stabilizing treatment used in bipolar and other psychiatric disorders. The molecular mechanisms underlying lithium action remain poorly understood. Adenosine is a neuromodulator that possesses anticonvulsant and neuroprotective properties and the ecto-nucleotidase pathway is a metabolic source of the extracellular adenosine. Here we investigated the effect of lithium on the ecto-nucleotidase pathway in synaptosomes from hippocampus and cerebral cortex of adult rats. Male Wistar rats received standard rat chow with lithium chloride (2.5 mg/g of chow) and NaCl (17 mg/g of chow) during 4 weeks. The serum lithium levels were 1.18 +/- 0.05 mEq./L. ATP and AMP hydrolysis was significantly increased (20 and 35%, respectively) in hippocampal synaptosomes of rats chronically treated with lithium chloride. No significant differences were observed in the hydrolysis of the three nucleotides by cortical synaptosomes. In conclusion, the modulation of the ecto-nucleotidase pathway may be a new explanation for the potential neuroprotective lithium action in hippocampal lesions.
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Affiliation(s)
- Leandre Carmem Wilot
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Rua Ramiro Barcellos 2600 - anexo, 90035-003, Porto Alegre, RS, Brasil
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9
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Vlajkovic SM, Housley GD, Muñoz DJB, Robson SC, Sévigny J, Wang CJH, Thorne PR. Noise exposure induces up-regulation of ecto-nucleoside triphosphate diphosphohydrolases 1 and 2 in rat cochlea. Neuroscience 2004; 126:763-73. [PMID: 15183524 DOI: 10.1016/j.neuroscience.2004.04.023] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2004] [Indexed: 12/01/2022]
Abstract
Extracellular ATP acting via P2 receptors in the inner ear initiates a variety of signaling pathways that may be involved in noise-induced cochlear injury. Nucleoside triphosphate diphosphohydrolase (NTPDase)1/CD39 and NTPDase2/CD39L1 are key elements for regulation of extracellular nucleotide concentrations and P2 receptor signaling in the cochlea. This study characterized the effect of noise exposure on regulation of NTPDase1 and NTPDase2 expression in the cochlea using a combination of real-time RT-PCR, immunohistochemistry and functional studies. Adult Wistar rats were exposed to broad band noise at 90 dB and 110 dB sound pressure level (SPL) for 72 h. Exposure to 90 dB SPL induced a small and temporary change of auditory thresholds (temporary threshold shift), while exposure to 110 dB SPL induced a robust and permanent change of auditory thresholds (permanent threshold shift). NTPDase1 and NTPDase2 mRNA transcripts were upregulated in the cochlea exposed to 110 dB SPL, while mild noise (90 dB SPL) altered only NTPDase1 mRNA expression levels. Changes in NTPDases expression did not correlate with levels of circulating corticosterone, implying that the up-regulation of NTPDases expression was not stress-related. Semi-quantitative immunohistochemistry in the cochlea exposed to 110 dB SPL localized the increased NTPDase1 and NTPDase2 immunostaining in the stria vascularis and up-regulation of NTPDase2 in the intraganglionic spiral bundle. In contrast, NTPDase1 was down-regulated in the cell bodies of the spiral ganglion neurones. Distribution of NTPDases was not altered in the cochlea exposed to 90 dB SPL. Functional studies revealed increased ectonucleotidase activities in the cochlea after exposure to 110 dB SPL, consistent with up-regulation of NTPDases. The changes in NTPDases expression may reflect adaptive response of cochlear tissues to limit ATP signaling during noise exposure.
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Affiliation(s)
- S M Vlajkovic
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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Kukulski F, Komoszyński M. Purification and characterization of NTPDase1 (ecto-apyrase) and NTPDase2 (ecto-ATPase) from porcine brain cortex synaptosomes. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:3447-54. [PMID: 12899702 DOI: 10.1046/j.1432-1033.2003.03734.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We purified to homogeneity and characterized NTPDase1 and NTPDase2 from porcine brain cortex synaptosomes. SDS/PAGE and immunoblotting with antibodies specific to these enzymes revealed a molecular mass estimated at 72 kDa for NTPDase1 and 66 for NTPDase2. Both enzymes exhibited kinetic properties typical for all members of the NTPDase family, e.g. low substrate specificity for tri- and diphosphonucleosides, divalent cations dependency and insensitivity towards ATPase inhibitors. The calculated Km value for NTPDase1 in respect to ATP as a substrate (97 microm) was three times lower in comparison to analogous values for NTPDase2 (270 microm). Additionally, NTPDase1 had a three times higher Kcat/Km coefficient than NTPDase2 (860 and 833 micromol product.s(-1), respectively). We have also demonstrated that in spite of differences in the affinity of ATP for both hydrolases, these enzymes have similar molecular activity. Taken together, these results indicate that NTPDase1 would terminate P2 receptor-mediated signal transmission whereas activity of NTPDase2 may contribute to decreasing high (toxic) concentrations of ATP and/or to production of another signal molecule, ADP.
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Affiliation(s)
- Filip Kukulski
- Department of Biochemistry, Institute of General and Molecular Biology, N. Copernicus University, Toruń, Poland
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Balz D, de Souza Wyse AT, Morsch VM, da Silva AC, Vieira VL, Morsch ALB, Schetinger MRC. In vitro effects of L-arginine and guanidino compounds on NTPDase1 and 5'-nucleotidase activities from rat brain synaptosomes. Int J Dev Neurosci 2003; 21:75-82. [PMID: 12615083 DOI: 10.1016/s0736-5748(02)00138-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Tissue accumulation of arginine (Arg), N-acetylarginine (NA), argininic acid (AA) and homoarginine (HA) occurs in hyperargininemia, an inborn error of the urea cycle. In the present study, we investigated the in vitro effects of Arg, NA, AA and HA on NTPDase1 and 5'-nucleotidase activities from synaptosomal cerebral cortex of rats. The results showed that Arg enhances NTPDase1 activity at the high concentrations tested (1.5 and 3.0mM) for both the ATP and ADP nucleotides. Activation was also observed with other guanidino compounds tested: NA, AA and HA activated ATP and ADP hydrolysis in all experiments at the concentration of 25 microM. Besides this, NA and AA activated ATP hydrolysis at a lower concentration (1 microM). In another set of experiments, we verified the effect of Arg on purified apyrase at pH 8.0 and 6.5 and observed an increase in the enzyme activity at all Arg concentrations tested (0.01-3.0mM). In contrast, Arg and the other guanidino compounds tested did not alter 5'-nucleotidase activity. These results suggest that changes in nucleotide hydrolysis may be involved in the brain dysfunction caused by hyperargininemia amongst other potential pathophysiological mechanisms involved in this condition.
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Affiliation(s)
- Daniela Balz
- Departamento de Qui;mica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Av. Roraima, 97105-900, RS, Santa Maria, Brazil
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12
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Schetinger MR, Vieira VL, Morsch VM, Balz D. ATP and ADP hydrolysis in fish, chicken and rat synaptosomes. Comp Biochem Physiol B Biochem Mol Biol 2001; 128:731-41. [PMID: 11290455 DOI: 10.1016/s1096-4959(00)00367-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Ecto-enzymes capable of hydrolyzing ATP and ADP (NTPDase) are present in the central nervous system of various species. In the present investigation we studied the synaptosomal NTPDase (ATP diphosphohydrolase, apyrase, E.C. 3.6.1.5) from fish, chicken and rats under different conditions and in the presence of several classical inhibitors. The cation concentration required for maximal activity was 0.5 mM for fish, 1.0 mM for chickens and 1.5 mM for rats with both substrates. The results showed that the pH optimum for all animal preparations was close to 8.0. The temperature used was 25-27 degrees C for fish and 35-37 degrees C for chicken and rat preparations. The inhibitors azide and fluoride only inhibited the preparation at high concentrations (10 mM). Lanthanum (0.1-0.4 mM), N-ethylmaleimide (0.4-3.0 mM) and ouabain (0.5-3.0 mM) had no effect on NTPDase activity from fish, chickens or rats. Orthovanadate (0.1-0.3 mM) only inhibited fish synaptosomal NTPDase. Trifluoperazine (0.05-0.2 mM) and suramin (0.03-0.3 mM) inhibited NTPDase at all concentrations tested. Suramin was the most potent compound in causing inhibition, presenting inhibition at 30 microM. Our results demonstrate that the synaptosomal NTPDase response to several factors is similar in fish, chickens and rats, and that the enzyme presents functional homology.
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Affiliation(s)
- M R Schetinger
- Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, CEP 97105-900, RS, Santa Maria, Brazil.
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Bonan CD, Schetinger MRC, Battastini AMO, Sarkis JJF. Ectonucleotidases and synaptic plasticity: Implications in physiological and pathological conditions. Drug Dev Res 2001. [DOI: 10.1002/ddr.1098] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wink MR, Lenz G, Rodnight R, Sarkis JJ, Battastini AM. Identification of brain ecto-apyrase as a phosphoprotein. Mol Cell Biochem 2000; 213:11-6. [PMID: 11129948 DOI: 10.1023/a:1007194229587] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Ecto-apyrase is a transmembrane glycoprotein that hydrolyzes extracellular nucleoside tri- or diphosphates. Apyrase activity is affected by several physiological and pathological conditions indicating the existence of regulatory mechanisms. Considering that apyrase presents consensus phosphorylation sites, we studied the phosphorylation of this enzyme. We found an overlay of the immunoblotting and phosphorylated bands in three different preparations from rat brain: (a) hippocampal slices, (b) synaptic plasma membrane fragments and (c) cultured astrocytes. In addition, two-dimensional electrophoresis separations with human astrocytoma cells were done to identify unequivocally the coincidence between the immunodetected and phosphorylated protein. These observations indicate that apyrase can be detected as a phosphoprotein, with obvious implications in the regulation of this enzyme.
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Affiliation(s)
- M R Wink
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Instituto de Biociências, UFRGS, Porto Alegre, RS, Brasil
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Schetinger MR, Porto NM, Moretto MB, Morsch VM, da Rocha JB, Vieira V, Moro F, Neis RT, Bittencourt S, Bonacorso HG, Zanatta N. New benzodiazepines alter acetylcholinesterase and ATPDase activities. Neurochem Res 2000; 25:949-55. [PMID: 10959491 DOI: 10.1023/a:1007500424392] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study examines the effect of new 1,5 benzodiazepines on acetylcholinesterase (AChE) and ATPDase (apyrase) activities from cerebral cortex of adult rats. Simultaneously, the effects of the classical 1,4-benzodiazepine on these enzymes were also studied for comparative purpose. The compounds 2-trichloromethyl-4-phenyl-3H-1,5-benzodiazepin and 2-trichloromethyl-4(p-methyl-phenyl)-3H- 1,5-benzodiazepin significantly inhibited acetylcholinesterase activity (p < 0.01) when tested in the range of 0.18-0.35 mM. The inhibition caused by these two new benzodiazepines was noncompetitive in nature. Similarly, at concentrations ranging from 0.063 to 0.25 mM, the 1,5 benzodiazepines inhibited ATP and ADP hydrolysis by synaptosomes from cerebral cortex (p < 0.01). However, the inhibition of nucleotide hydrolysis was uncompetitive in nature. Our results suggest that, although diazepam and the new benzodiazepines have chemical differences, they both presented an inhibitory effect on acetylcholinesterase and ATPDase activities.
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Affiliation(s)
- M R Schetinger
- Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, RS, Brasil.
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16
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de Souza Wyse AT, Streck EL, Worm P, Wajner A, Ritter F, Netto CA. Preconditioning prevents the inhibition of Na+,K+-ATPase activity after brain ischemia. Neurochem Res 2000; 25:971-5. [PMID: 10959493 DOI: 10.1023/a:1007504525301] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Application of single transient forebrain ischemia (ISC) in adult Wistar rats, lasting 2 or 10 min, caused inhibition of Na+,K+-ATPase activity in cytoplasmic membrane fractions of hippocampus and cerebral cortex immediately after the event. In the 2-min ISC group followed by 60 min of reperfusion, the enzyme inhibition was maintained in the cortex, while there was an increase in hippocampal enzyme activity; both effects were over 1 day after the event. However, in the 10-min ISC group enzyme inhibition had been maintained for 7 days in both cerebral structures. Interestingly, ischemic preconditioning (2-min plus 10-min ISC, with a 24-hour interval in between) prevented the inhibitory effect of ischemia/reperfusion on Na+,K+-ATPase activity observed either after a single insult of 2 min or 10 min ischemia. We suggest that the maintenance of Na+,K+-ATPase activity afforded by preconditioning be related to cellular neuroprotection.
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Affiliation(s)
- A T de Souza Wyse
- Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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