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Pérez de Lara MJ, Guzmán-Aranguez A, Gómez-Villafuertes R, Gualix J, Miras-Portugal MT, Pintor J. Increased Ap 4A levels and ecto-nucleotidase activity in glaucomatous mice retina. Purinergic Signal 2018; 14:259-270. [PMID: 29948577 DOI: 10.1007/s11302-018-9612-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 05/22/2018] [Indexed: 10/14/2022] Open
Abstract
The pathogenesis of glaucoma involves numerous intracellular mechanisms including the purinergic system contribution. Furthermore, the presence and release of nucleotides and dinucleotides during the glaucomatous damage and the maintenance of degradation machinery through ecto-nucleotidase activity are participating in the modulation of the suitable extracellular complex balance. The aim of this study was to investigate the levels of diadenosine tetraphosphate (Ap4A) and the pattern of ecto-nucleotidase activity expression in glaucomatous retinas during the progress the pathology. Ap4A levels were analyzed by HPLC in glaucomatous retinas from the DBA/2J mice at 3, 9, 15, and 23 months of age. For that, retinas were dissected as flattened whole-mounts and stimulated in Ringer buffer with or without 59 mM KCl. NPP1 expression was analyzed by RT-PCR and western blot and its distribution was assessed by immunohistochemistry studies examined under confocal microscopy. Glaucomatous mice exhibited Ap4A values, which changed in stimulated retinas as long as the pathology progressed varying from 0.73 ± 0.04 (3 months) to 0.170 ± 0.05 pmol/mg retina (23 months). Concomitantly, NPP1 expression was significantly increased (82.15%) in the DBA/2J mice at 15 months. Furthermore, immunohistochemical studies showed that NPP1 labeling was stronger in OPL and IPL labeling tangentially in the vitreal part of the retina and was upregulated at 15 months of age. Our findings demonstrate that Ap4A decreased levels may be related with exacerbated activity of NPP1 protein in glaucomatous degeneration and in this way contributing to elucidate different mechanisms involved in retinal impairment in glaucomatous degeneration.
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Affiliation(s)
- María J Pérez de Lara
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, 28037, Madrid, Spain
| | - Ana Guzmán-Aranguez
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, 28037, Madrid, Spain
| | - Rosa Gómez-Villafuertes
- Department of Biochemistry and Molecular Biology IV, Faculty of Veterinary, Complutense University of Madrid, Av/ Puerta del Hierro s/n, 28040, Madrid, Spain
| | - Javier Gualix
- Department of Biochemistry and Molecular Biology IV, Faculty of Veterinary, Complutense University of Madrid, Av/ Puerta del Hierro s/n, 28040, Madrid, Spain
| | - María Teresa Miras-Portugal
- Department of Biochemistry and Molecular Biology IV, Faculty of Veterinary, Complutense University of Madrid, Av/ Puerta del Hierro s/n, 28040, Madrid, Spain
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Complutense University of Madrid, c/Arcos de Jalón 118, 28037, Madrid, Spain.
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Abstract
P2Y receptors (P2YRs) are a family of G protein-coupled receptors activated by extracellular nucleotides. Physiological P2YR agonists include purine and pyrimidine nucleoside di- and triphosphates, such as ATP, ADP, UTP, UDP, nucleotide sugars, and dinucleotides. Eight subtypes exist, P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13, and P2Y14, which represent current or potential future drug targets. Here we provide a comprehensive overview of ligands for the subgroup of the P2YR family that is activated by uracil nucleotides: P2Y2 (UTP, also ATP and dinucleotides), P2Y4 (UTP), P2Y6 (UDP), and P2Y14 (UDP, UDP-glucose, UDP-galactose). The physiological agonists are metabolically unstable due to their fast hydrolysis by ectonucleotidases. A number of agonists with increased potency, subtype-selectivity and/or enzymatic stability have been developed in recent years. Useful P2Y2R agonists include MRS2698 (6-01, highly selective) and PSB-1114 (6-05, increased metabolic stability). A potent and selective P2Y2R antagonist is AR-C118925 (10-01). For studies of the P2Y4R, MRS4062 (3-15) may be used as a selective agonist, while PSB-16133 (10-06) is a selective antagonist. Several potent P2Y6R agonists have been developed including 5-methoxyuridine 5'-O-((Rp)α-boranodiphosphate) (6-12), PSB-0474 (3-11), and MRS2693 (3-26). The isocyanate MRS2578 (10-08) is used as a selective P2Y6R antagonist, although its reactivity and low water-solubility are limiting. With MRS2905 (6-08), a potent and metabolically stable P2Y14R agonist is available, while PPTN (10-14) represents a potent and selective P2Y14R antagonist. The radioligand [3H]UDP can be used to label P2Y14Rs. In addition, several fluorescent probes have been developed. Uracil nucleotide-activated P2YRs show great potential as drug targets, especially in inflammation, cancer, cardiovascular and neurodegenerative diseases.
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Loukovaara S, Sahanne S, Jalkanen S, Yegutkin GG. Increased intravitreal adenosine 5'-triphosphate, adenosine 5'-diphosphate and adenosine 5'-monophosphate levels in patients with proliferative diabetic retinopathy. Acta Ophthalmol 2015; 93:67-73. [PMID: 25079888 DOI: 10.1111/aos.12507] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/04/2014] [Indexed: 12/28/2022]
Abstract
PURPOSE Extracellular purines play important role in ocular physiology, diabetes, vascular remodelling and adaptation to inflammation. This study was aimed to evaluate intravitreal purine levels in patients with diabetic retinopathy (DR) and other non-vascular vitreoretinal eye diseases. METHODS Vitreous samples were collected at the start of the three-port pars plana vitrectomy. Study group comprised 55 eyes operated due to sight-threatening forms of DR, including eyes of 24 patients with proliferative DR. Of the 143 non-diabetic controls, 112 had rhegmatogenous retinal detachment and 31 macular hole or pucker. Intravitreal purine concentrations were determined using a combination of bioluminescent [adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP)] and fluorometric [adenosine 5'-monophosphate (AMP), adenosine, inosine] enzyme-coupled sensing assays. RESULTS Compared with non-diabetic controls, DR eyes contained significantly higher (p < 0.01) concentrations of ATP (4.2 ± 0.6 versus 34.5 ± 13.7 nm; mean ± SEM), ADP (19.5 ± 2.7 versus 43.7 ± 14.5 nm) and AMP (1290 ± 115 versus 1876 ± 190 nm). Intravitreal adenosine and inosine levels varied within submicromolar to low micromolar range, and their concentrations did not differ between the groups studied. CONCLUSIONS High concentrations of intravitreal nucleotides ATP, ADP and AMP may be related to the pathogenesis of sight-threatening forms of DR.
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Affiliation(s)
- Sirpa Loukovaara
- Unit of Vitreoretinal Surgery; Department of Ophthalmology; Helsinki University Central Hospital; Helsinki Finland
| | - Sari Sahanne
- Unit of Anesthesiology and Intensive Care Medicine; Eye-ENT Hospital; Helsinki University Central Hospital; Helsinki Finland
| | - Sirpa Jalkanen
- MediCity Research Laboratory; University of Turku and Turku University Hospital; Turku Finland
- National Institute for Health and Welfare; Turku Finland
| | - Gennady G. Yegutkin
- MediCity Research Laboratory; University of Turku and Turku University Hospital; Turku Finland
- National Institute for Health and Welfare; Turku Finland
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Guzman-Aranguez A, Santano C, Martin-Gil A, Fonseca B, Pintor J. Nucleotides in the eye: focus on functional aspects and therapeutic perspectives. J Pharmacol Exp Ther 2013; 345:331-41. [PMID: 23504005 DOI: 10.1124/jpet.112.202473] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The presence and activity of nucleotides and dinucleotides in the physiology of most, if not all, organisms, from bacteria to humans, have been recognized by the scientific community, and the eye is no exception. Nucleotides in the dynamic fluids interact with many ocular structures, such as the tears and aqueous humor. Moreover, high concentrations of nucleotides in these secretions may reflect disease states such as dry eye and glaucoma. Apart from the nucleotide concentration in these fluids, P2 purinergic receptors have been described on the ocular surface (cornea and conjunctiva), anterior pole (ciliary body, trabecular meshwork), and posterior pole (retina). P2X and P2Y purinergic receptors are essential in maintaining the homeostasis of ocular processes, such as tear secretion, aqueous humor production, or retinal modulation. When they are functioning properly, they allow the eye to do its job (to see), but in some cases, a lack or an excess of nucleotides or a malfunction in the corresponding purinergic receptors leads to disease. This Perspective is focused on the nucleotides and dinucleotides and the P2 purinergic receptors in the eye and how they contribute to normal and disease states. We also emphasize the action of nucleotides and their receptors and antagonists as potential therapeutic agents.
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Affiliation(s)
- Ana Guzman-Aranguez
- Department of Biochemistry and Molecular Biology, Faculty of Optics and Optometry, Universidad Complutense Madrid, C/Arcos de Jalón 118, 28037 Madrid, Spain
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Mediero A, Crooke A, Guzmán-Aránguez A, Pintor J. Phospholipase C/Protein Kinase C pathway is essential for corneal re-epithelialization induced by Ap(4)A. Curr Eye Res 2011; 36:1108-15. [PMID: 21988553 DOI: 10.3109/02713683.2011.614371] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE We have previously demonstrated the importance of P2Y(2) receptors in the corneal re-epithelialization effect triggered by diadenosine tetraphosphate (Ap(4)A). In addition, we have also shown the ERK1/2 and ROCK-I activation in Ap(4)A-wound repair response. Phospholipase C/Protein Kinase C (PLC/PKC) pathway activation has been suggested as a molecular mechanism of growth factors-modulated corneal cell migration and P2Y(2) agonists. Hence, the aim of this study is to investigate the role of PLC/PKC cascade in the modification of re-epithelialization rate triggered by Ap(4)A in an established corneal epithelial cell line (Statens Seruminstitut rabbit cornea [SIRC] cells). METHODS In wounded confluent SIRC cell monolayers and in the presence or absence of Ap(4)A 100 μM, a group of PLC/PKC inhibitors (U73122 3 μM, Staurosporine 1 nM and Bisindolylmaleimide-I 10 μM) and activator (PDBU 1 μM) were assayed and the migration rate was evaluated. Also, the activation of ERK1/2 and ROCK-I was examined by Western blot assay after treatment with or without Ap(4)A, U73122, Staurosporine, Bisindolylmaleimide-I and PDBU. RESULTS Pre-treatment of wounded SIRC cells with PLC/PKC inhibitors significantly diminished the Ap(4)A-stimulated cell migration rate. Furthermore, PLC/PKC inhibitors also reduced ERK1/2 phosphorylation and ROCK-I activation triggered by Ap(4)A. CONCLUSIONS The present study shows the involvement of PLC/PKC pathway in the activation of ERK1/2 and ROCK-I downstream signal transduction pathways stimulated by Ap(4)A/P2Y(2) receptor during corneal epithelial wound repair.
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Affiliation(s)
- Aránzazu Mediero
- Departamento de Bioquímica, EU Óptica, Universidad Complutense de Madrid, Madrid, Spain
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Burnstock G, Kennedy C. P2X receptors in health and disease. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 61:333-372. [PMID: 21586364 DOI: 10.1016/b978-0-12-385526-8.00011-4] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Seven P2X receptor subunits have been cloned which form functional homo- and heterotrimers. These are cation-selective channels, equally permeable to Na(+) and K(+) and with significant Ca(2+) permeability. The three-dimensional structure of the P2X receptor is described. The channel pore is formed by the α-helical transmembrane spanning region 2 of each subunit. When ATP binds to a P2X receptor, the pore opens within milliseconds, allowing the cations to flow. P2X receptors are expressed on both central and peripheral neurons, where they are involved in neuromuscular and synaptic neurotransmission and neuromodulation. They are also expressed in most types of nonneuronal cells and mediate a wide range of actions, such as contraction of smooth muscle, secretion, and immunomodulation. Changes in the expression of P2X receptors have been characterized in many pathological conditions of the cardiovascular, gastrointestinal, respiratory, and urinogenital systems and in the brain and special senses. The therapeutic potential of P2X receptor agonists and antagonists is currently being investigated in a range of disorders, including chronic neuropathic and inflammatory pain, depression, cystic fibrosis, dry eye, irritable bowel syndrome, interstitial cystitis, dysfunctional urinary bladder, and cancer.
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Affiliation(s)
- G Burnstock
- Autonomic Neuroscience Centre, University College Medical School, London, United Kingdom
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Ginsburg-Shmuel T, Haas M, Schumann M, Reiser G, Kalid O, Stern N, Fischer B. 5-OMe-UDP is a potent and selective P2Y(6)-receptor agonist. J Med Chem 2010; 53:1673-85. [PMID: 20095577 DOI: 10.1021/jm901450d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
P2Y nucleotide receptors (P2Y-Rs) play important physiological roles. However, most of the P2Y-R subtypes are still lacking potent and selective agonists and antagonists. Based on data mining analysis of binding interactions in 44 protein-uridine nucleos(t)ides complexes, we designed uracil nucleotides, substituted at the C5/C6 position. All C6-substituted derivatives were inactive at the P2Y(2,4,6)-Rs, while out of the C5-substituted analogues, only 5-OMe-UD(T)P showed activity. To rationalize the data, the ionization and conformation of these analogues were evaluated. The pK(a) values of most analogues substituted at the C5/C6 positions were unaltered compared to UTP (pK(a) 9.42), except for 5-F-UTP nucleotide (pK(a) 7.85). C6-substituted analogues adopt the syn or high-syn conformations, which are disfavored by the receptors, while 5-OMe-UD(T)P adopt the favored anti conformation. Furthermore, 5-OMe-UDP adopts the S sugar puckering, which is the conformation preferred by the P2Y(6)-R, but not the P2Y(2)- or P2Y(4)-Rs. 5-OMe-UDP fulfills the conformational and H-bonding requirements of P2Y(6)-R, thus, making a potent P2Y(6)-R agonist (EC(50) 0.08 microM), more than UDP (EC(50) 0.14 microM).
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Affiliation(s)
- Tamar Ginsburg-Shmuel
- Department of Chemistry, Gonda-Goldschmied Medical Research Center, Bar-Ilan University, Ramat-Gan 52900, Israel
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New treatments for ocular hypertension. Auton Neurosci 2009; 147:14-9. [PMID: 19176290 DOI: 10.1016/j.autneu.2008.12.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 12/18/2008] [Accepted: 12/22/2008] [Indexed: 12/15/2022]
Abstract
Glaucoma is a neurodegenerative pathology that affects the optic nerve producing blindness. This disease is often a consequence of an abnormal increase of intraocular pressure (IOP) due to a reduction in the ability of the eye to drain a transparent fluid termed aqueous humour. The dynamics of the aqueous humour is highly controlled by the autonomic nervous system, mainly the sympathetic, regulating its production and parasympathetic controlling the evacuation of aqueous humour. This has led pharmaceutical companies to develop chemicals which, by acting via different targets can substantially reduce IOP. Parasympathomimetics, adrenergic antagonists, plus eventually adrenergic agonists, are commonly used for the reduction of IOP and therefore for treatment of glaucoma. New substances linked to the nervous system that innervates the eye are emerging as interesting candidates. Nucleotides, commonly costored with catecholamines or acetylcholine or the indole melatonin, present interesting properties reducing IOP. Moreover new technological ideas such as the use of siRNA (small interference RNA) to silence protein expression demonstrate the relevance of this method to approach ocular hypertension and glaucoma from a different point of view. These three main groups of molecules: nucleotides, melatonins and siRNAs, are reviewed since they appear as firm candidates for the treatment of glaucoma in the near future.
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Abstract
This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration. Emphasis is placed on the physiology and pathophysiology of ATP, but extracellular roles of its breakdown product, adenosine, are also considered because of their intimate interactions. The early history of the involvement of ATP in autonomic and skeletal neuromuscular transmission and in activities in the central nervous system and ganglia is reviewed. Brief background information is given about the identification of receptor subtypes for purines and pyrimidines and about ATP storage, release, and ectoenzymatic breakdown. Evidence that ATP is a cotransmitter in most, if not all, peripheral and central neurons is presented, as well as full accounts of neurotransmission and neuromodulation in autonomic and sensory ganglia and in the brain and spinal cord. There is coverage of neuron-glia interactions and of purinergic neuroeffector transmission to nonmuscular cells. To establish the primitive and widespread nature of purinergic neurotransmission, both the ontogeny and phylogeny of purinergic signaling are considered. Finally, the pathophysiology of purinergic neurotransmission in both peripheral and central nervous systems is reviewed, and speculations are made about future developments.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neurscience Centre, Royal Free and University College Medical School, London, UK.
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Abbracchio MP, Burnstock G, Boeynaems JM, Barnard EA, Boyer JL, Kennedy C, Knight GE, Fumagalli M, Gachet C, Jacobson KA, Weisman GA. International Union of Pharmacology LVIII: update on the P2Y G protein-coupled nucleotide receptors: from molecular mechanisms and pathophysiology to therapy. Pharmacol Rev 2006; 58:281-341. [PMID: 16968944 PMCID: PMC3471216 DOI: 10.1124/pr.58.3.3] [Citation(s) in RCA: 987] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
There have been many advances in our knowledge about different aspects of P2Y receptor signaling since the last review published by our International Union of Pharmacology subcommittee. More receptor subtypes have been cloned and characterized and most orphan receptors de-orphanized, so that it is now possible to provide a basis for a future subdivision of P2Y receptor subtypes. More is known about the functional elements of the P2Y receptor molecules and the signaling pathways involved, including interactions with ion channels. There have been substantial developments in the design of selective agonists and antagonists to some of the P2Y receptor subtypes. There are new findings about the mechanisms underlying nucleotide release and ectoenzymatic nucleotide breakdown. Interactions between P2Y receptors and receptors to other signaling molecules have been explored as well as P2Y-mediated control of gene transcription. The distribution and roles of P2Y receptor subtypes in many different cell types are better understood and P2Y receptor-related compounds are being explored for therapeutic purposes. These and other advances are discussed in the present review.
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Affiliation(s)
- Maria P Abbracchio
- Department of Pharmacological Sciences, University of Milan, Milan, Italy
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Abstract
The concept of a purinergic signaling system, using purine nucleotides and nucleosides as extracellular messengers, was first proposed over 30 years ago. After a brief introduction and update of purinoceptor subtypes, this article focuses on the diverse pathophysiological roles of purines and pyrimidines as signaling molecules. These molecules mediate short-term (acute) signaling functions in neurotransmission, mechanosensory transduction, secretion and vasodilatation, and long-term (chronic) signaling functions in cell proliferation, differentiation, and death involved in development and regeneration. Plasticity of purinoceptor expression in pathological conditions is frequently observed, including an increase in the purinergic component of autonomic cotransmission. Recent advances in therapies using purinergic-related drugs in a wide range of pathological conditions will be addressed with speculation on future developments in the field.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, Royal Free and University College Medical School, London NW3 2PF, UK.
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Burnstock G. Historical review: ATP as a neurotransmitter. Trends Pharmacol Sci 2006; 27:166-76. [PMID: 16487603 DOI: 10.1016/j.tips.2006.01.005] [Citation(s) in RCA: 378] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 11/22/2005] [Accepted: 01/25/2006] [Indexed: 02/07/2023]
Abstract
Purinergic signalling is now recognized to be involved in a wide range of activities of the nervous system, including neuroprotection, central control of autonomic functions, neural-glial interactions, control of vessel tone and angiogenesis, pain and mechanosensory transduction and the physiology of the special senses. In this article, I give a personal retrospective of the discovery of purinergic neurotransmission in the early 1970s, the struggle for its acceptance for approximately 20 years, the expansion into purinergic cotransmission and its eventual acceptance when receptor subtypes for ATP were cloned and characterized and when purinergic synaptic transmission between neurons in the brain and peripheral ganglia was described in the early 1990s. I also discuss the current status of the field, including recent interest in the pathophysiology of purinergic signalling and its therapeutic potential.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, Royal Free & University College Medical School, Rowland Hill Street, London NW3 2PF, UK.
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Soto D, Pintor J, Peral A, Gual A, Gasull X. Effects of dinucleoside polyphosphates on trabecular meshwork cells and aqueous humor outflow facility. J Pharmacol Exp Ther 2005; 314:1042-51. [PMID: 15947035 DOI: 10.1124/jpet.105.085274] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The most important risk factor for the development of glaucoma is elevated intraocular pressure (IOP). Hypotensive drugs decrease IOP, preventing optic nerve damage and further vision loss. The balance between aqueous humor (AH) production and drainage determines IOP, and problems in AH outflow pathways are associated with open-angle glaucoma development. Previous studies have shown the presence of diadenosine tetraphosphate (Ap(4)A) and pentaphosphate (Ap(5)A) in the AH. Topic application of Ap(4)A to the cornea decreased IOP, whereas Ap(5)A increased it. Because dinucleoside polyphosphates stimulate P2Y purinergic receptors, we studied their presence in trabecular meshwork (TM) cells. Additionally, the effects of diadenosine polyphosphates (Ap(n)As; n = 3-5) and Up(4)U (P(1),P(4)-(diuridine 5')-tetraphosphate; INS365) in outflow facility were tested. P2Y(1), P2Y(2), and P2Y(4) receptors were detected in TM cells by Western blot and immunocytochemistry. In TM cells, Ap(3)A, Ap(4)A, and Ap(5)A induced discrete intracellular calcium concentration ([Ca(2+)](i)) mobilizations compared with higher and more sustained [Ca(2+)](i) mobilizations after Up(4)U application. In bovine ocular anterior segments perfused at constant pressure, 1 microM Ap(3)A or Ap(4)A increased outflow facility, whereas Up(4)U or Ap(5)A did not modify it. 2-MeSADP, a selective P2Y(1) agonist, induced outflow facility increases similar to those obtained after Ap(3)A and Ap(4)A, and these were prevented by addition of the selective P2Y(1) receptor antagonist MRS-2179 (2'-deoxy-N(6)-methyladenosine-3',5'-diphosphate). Our results demonstrate that the hypotensive effect of Ap(4)A and other dinucleotides is mediated, at least in part, by increasing trabecular outflow facility through activation of P2Y(1) receptors. The latter would seem to be an interesting target in the development of antiglaucomatous drugs to selectively increase AH outflow.
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Affiliation(s)
- David Soto
- Laboratori de Neurofisiologia, Facultat de Medicina-Institut d'Investigacions Biomèdiques August Pi i Sunyer, Universitat de Barcelona, Spain
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Pintor J, Bautista A, Carracedo G, Peral A. UTP and diadenosine tetraphosphate accelerate wound healing in the rabbit cornea. Ophthalmic Physiol Opt 2004; 24:186-93. [PMID: 15130167 DOI: 10.1111/j.1475-1313.2004.00182.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nucleotides are naturally occurring substances present in tear film that can stimulate tear secretion in animals and humans. We investigated whether certain nucleotides can affect the rate of wound healing in the cornea of white rabbits. In the absence of any added compound, the rate of healing was 72.4 +/- 2.2 microm h(-1). Of all the tested nucleotides, UTP and Ap(4)A were the most active ones, maximally increasing the rate of healing to 121.6 +/- 3.7 and 93.7 +/- 3.2 microm h(-1), respectively. Responses to UTP were dose dependent. UTP had a pD(2) value of 8.9 +/- 0.1 (EC(50): 1.25 nM). P2 purinoceptor antagonists such as suramin and reactive blue-2, inhibited the effect of UTP indicating the involvement of P2Y receptors. Mitogen-activated protein kinase (MAPK) cascade inhibitors also abolished the effects of UTP, suggesting that P2Y receptors are coupled to the MAPK cascade, and that this is involved in controlling the rate of epithelial cell migration.
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Affiliation(s)
- Jesús Pintor
- Departamento de Bioquímica, Escuela Universtaria de Optica, Universidad Complutense de Madrid, c/Arcos de Jalon s/n, Madrid 28037, Spain.
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