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Burnstock G. Introduction to Purinergic Signalling in the Brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1202:1-12. [PMID: 32034706 DOI: 10.1007/978-3-030-30651-9_1] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ATP is a cotransmitter with glutamate, noradrenaline, GABA, acetylcholine and dopamine in the brain. There is a widespread presence of both adenosine (P1) and P2 nucleotide receptors in the brain on both neurons and glial cells. Adenosine receptors play a major role in presynaptic neuromodulation, while P2X ionotropic receptors are involved in fast synaptic transmission and synaptic plasticity. P2Y G protein-coupled receptors are largely involved in presynaptic activities, as well as mediating long-term (trophic) signalling in cell proliferation, differentiation and death during development and regeneration. Both P1 and P2 receptors participate in neuron-glial interactions. Purinergic signalling is involved in control of cerebral vascular tone and remodelling and has been implicated in learning and memory, locomotor and feeding behaviour and sleep. There is increasing interest in the involvement of purinergic signalling in the pathophysiology of the CNS, including trauma, ischaemia, epilepsy, neurodegenerative diseases, neuropsychiatric and mood disorders, and cancer, including gliomas.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Royal Free Campus, Rowland Hill Street, NW3 2PF, London, UK.
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Conde SV, Monteiro EC, Sacramento JF. Purines and Carotid Body: New Roles in Pathological Conditions. Front Pharmacol 2017; 8:913. [PMID: 29311923 PMCID: PMC5733106 DOI: 10.3389/fphar.2017.00913] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/29/2017] [Indexed: 01/28/2023] Open
Abstract
It is known that adenosine and adenosine-5′-triphosphate (ATP) are excitatory mediators involved in carotid body (CB) hypoxic signaling. The CBs are peripheral chemoreceptors classically defined by O2, CO2, and pH sensors. When hypoxia activates the CB, it induces the release of neurotransmitters from chemoreceptor cells leading to an increase in the action potentials frequency at the carotid sinus nerve (CSN). This increase in the firing frequency of the CSN is integrated in the brainstem to induce cardiorespiratory compensatory responses. In the last decade several pathologies, as, hypertension, diabetes, obstructive sleep apnea and heart failure have been associated with CB overactivation. In the first section of the present manuscript we review in a concise manner fundamental aspects of purine metabolism. The second section is devoted to the role of purines on the hypoxic response of the CB, providing the state-of-the art for the presence of adenosine and ATP receptors in the CB; for the role of purines at presynaptic level in CB chemoreceptor cells, as well as, its metabolism and regulation; at postsynaptic level in the CSN activity; and on the ventilatory responses to hypoxia. Recently, we have showed that adenosine is involved in CB hypersensitization during chronic intermittent hypoxia (CIH), which mimics obstructive sleep apnea, since caffeine, a non-selective adenosine receptor antagonist that inhibits A2A and A2B adenosine receptors, decreased CSN chemosensory activity in animals subjected to CIH. Apart from this involvement of adenosine in CB sensitization in sleep apnea, it was recently found that P2X3 ATP receptor in the CB contributes to increased chemoreflex hypersensitivity and hypertension in spontaneously hypertension rats. Therefore the last section of this manuscript is devoted to review the recent findings on the role of purines in CB-mediated pathologies as hypertension, diabetes and sleep apnea emphasizing the potential clinical importance of modulating purines levels and action to treat pathologies associated with CB dysfunction.
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Affiliation(s)
- Silvia V Conde
- Centro de Estudos de Doenças Crónicas, NOVA Medical School - Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Emilia C Monteiro
- Centro de Estudos de Doenças Crónicas, NOVA Medical School - Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Joana F Sacramento
- Centro de Estudos de Doenças Crónicas, NOVA Medical School - Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
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Domingos LB, Hott SC, Terzian ALB, Resstel LBM. P2X7 purinergic receptors participate in the expression and extinction processes of contextual fear conditioning memory in mice. Neuropharmacology 2017; 128:474-481. [PMID: 28802645 DOI: 10.1016/j.neuropharm.2017.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/27/2017] [Accepted: 08/08/2017] [Indexed: 12/21/2022]
Abstract
The purinergic system consists of two large receptor families - P2X and P2Y. Both are activated by adenosine triphosphate (ATP), although presenting different functions. These receptors are present in several brain regions, including those involved in emotion and stress-related behaviors. Hence, they seem to participate in fear- and anxiety-related responses. However, few studies have investigated the purinergic system in threatening situations, as observed in contextual fear conditioning (CFC). Therefore, this study investigated the involvement of purinergic receptors in the expression and extinction of aversive memories. C57Bl/6 background mice were submitted to the CFC protocol. Wildtype (WT) mice received i.p. injection of either a nonselective P2 receptor (P2R) antagonist, P178 (10 or 30 mg/kg); a selective P2X7 receptor (P2X7R) antagonist, A438079 (10 mg/kg); a selective P2Y1 receptor (P2Y1R) antagonist, MRS2179 (10 mg/kg); or vehicle 10 min prior to or immediately after the extinction session. Additionally, P2X7R KO mice were tested in the CFC protocol. After P2R antagonist treatment, contextual fear recall increased, while acquisition of extinction was impaired. Similar results were observed with the selective P2X7R antagonist, but not with the selective P2Y1R antagonist. Interestingly, P2X7R KO mice showed increased contextual fear recall, associated with impaired acquisition of extinction, in accordance with pharmacologic P2X7R antagonism. Our results suggest that specific pharmacological or genetic blockade of P2X7R promotes anxiogenic-like effects, along with deficits in extinction learning. Thus, these receptors could present an alternative treatment of stress-related psychiatric disorders.
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Affiliation(s)
- L B Domingos
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - S C Hott
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - A L B Terzian
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - L B M Resstel
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
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Barańska J, Czajkowski R, Pomorski P. P2Y 1 Receptors - Properties and Functional Activities. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017. [PMID: 28639247 DOI: 10.1007/5584_2017_57] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In this chapter we try to show a comprehensive image of current knowledge of structure, activity and physiological role of the P2Y1 purinergic receptor. The structure, distribution and changes in the expression of this receptor are summarized, as well as the mechanism of its signaling activity by the intracellular calcium mobilization. We try to show the connection between the components of its G protein activation and cellular or physiological effects, starting from changes in protein phosphorylation patterns and ending with such remote effects as receptor-mediated apoptosis. The special emphasis is put on the role of the P2Y1 receptor in cancer cells and neuronal plasticity. We concentrate on the P2Y1 receptor, it is though impossible to completely abstract from other aspects of nucleotide signaling and cross-talk with other nucleotide receptors is here discussed. Especially, the balance between P2Y1 and P2Y12 receptors, sharing the same ligand but signaling through different pathways, is presented.
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Affiliation(s)
- Jolanta Barańska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., PL 02-093, Warsaw, Poland
| | - Rafał Czajkowski
- Laboratory of Spatial Memory, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., PL 02-093, Warsaw, Poland
| | - Paweł Pomorski
- Laboratory of Molecular Basis of Cell Motility, Department of Cell Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., PL 02-093, Warsaw, Poland.
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ATP from synaptic terminals and astrocytes regulates NMDA receptors and synaptic plasticity through PSD-95 multi-protein complex. Sci Rep 2016; 6:33609. [PMID: 27640997 PMCID: PMC5027525 DOI: 10.1038/srep33609] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 08/30/2016] [Indexed: 12/13/2022] Open
Abstract
Recent studies highlighted the importance of astrocyte-secreted molecules, such as ATP, for the slow modulation of synaptic transmission in central neurones. Biophysical mechanisms underlying the impact of gliotransmitters on the strength of individual synapse remain, however, unclear. Here we show that purinergic P2X receptors can bring significant contribution to the signalling in the individual synaptic boutons. ATP released from astrocytes facilitates a recruitment of P2X receptors into excitatory synapses by Ca2+-dependent mechanism. P2X receptors, co-localized with NMDA receptors in the excitatory synapses, can be activated by ATP co-released with glutamate from pre-synaptic terminals and by glia-derived ATP. An activation of P2X receptors in turn leads to down-regulation of postsynaptic NMDA receptors via Ca2+-dependent de-phosphorylation and interaction with PSD-95 multi-protein complex. Genetic deletion of the PSD-95 or P2X4 receptors obliterated ATP-mediated down-regulation of NMDA receptors. Impairment of purinergic modulation of NMDA receptors in the PSD-95 mutants dramatically decreased the threshold of LTP induction and increased the net magnitude of LTP. Our findings show that synergistic action of glia- and neurone-derived ATP can pre-modulate efficacy of excitatory synapses and thereby can have an important role in the glia-neuron communications and brain meta-plasticity.
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Cunha RA. How does adenosine control neuronal dysfunction and neurodegeneration? J Neurochem 2016; 139:1019-1055. [PMID: 27365148 DOI: 10.1111/jnc.13724] [Citation(s) in RCA: 320] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/23/2016] [Accepted: 06/23/2016] [Indexed: 12/11/2022]
Abstract
The adenosine modulation system mostly operates through inhibitory A1 (A1 R) and facilitatory A2A receptors (A2A R) in the brain. The activity-dependent release of adenosine acts as a brake of excitatory transmission through A1 R, which are enriched in glutamatergic terminals. Adenosine sharpens salience of information encoding in neuronal circuits: high-frequency stimulation triggers ATP release in the 'activated' synapse, which is locally converted by ecto-nucleotidases into adenosine to selectively activate A2A R; A2A R switch off A1 R and CB1 receptors, bolster glutamate release and NMDA receptors to assist increasing synaptic plasticity in the 'activated' synapse; the parallel engagement of the astrocytic syncytium releases adenosine further inhibiting neighboring synapses, thus sharpening the encoded plastic change. Brain insults trigger a large outflow of adenosine and ATP, as a danger signal. A1 R are a hurdle for damage initiation, but they desensitize upon prolonged activation. However, if the insult is near-threshold and/or of short-duration, A1 R trigger preconditioning, which may limit the spread of damage. Brain insults also up-regulate A2A R, probably to bolster adaptive changes, but this heightens brain damage since A2A R blockade affords neuroprotection in models of epilepsy, depression, Alzheimer's, or Parkinson's disease. This initially involves a control of synaptotoxicity by neuronal A2A R, whereas astrocytic and microglia A2A R might control the spread of damage. The A2A R signaling mechanisms are largely unknown since A2A R are pleiotropic, coupling to different G proteins and non-canonical pathways to control the viability of glutamatergic synapses, neuroinflammation, mitochondria function, and cytoskeleton dynamics. Thus, simultaneously bolstering A1 R preconditioning and preventing excessive A2A R function might afford maximal neuroprotection. The main physiological role of the adenosine modulation system is to sharp the salience of information encoding through a combined action of adenosine A2A receptors (A2A R) in the synapse undergoing an alteration of synaptic efficiency with an increased inhibitory action of A1 R in all surrounding synapses. Brain insults trigger an up-regulation of A2A R in an attempt to bolster adaptive plasticity together with adenosine release and A1 R desensitization; this favors synaptotocity (increased A2A R) and decreases the hurdle to undergo degeneration (decreased A1 R). Maximal neuroprotection is expected to result from a combined A2A R blockade and increased A1 R activation. This article is part of a mini review series: "Synaptic Function and Dysfunction in Brain Diseases".
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Affiliation(s)
- Rodrigo A Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,FMUC-Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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Burnstock G. Short- and long-term (trophic) purinergic signalling. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150422. [PMID: 27377731 PMCID: PMC4938022 DOI: 10.1098/rstb.2015.0422] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2016] [Indexed: 12/26/2022] Open
Abstract
There is long-term (trophic) purinergic signalling involving cell proliferation, differentiation, motility and death in the development and regeneration of most systems of the body, in addition to fast purinergic signalling in neurotransmission, neuromodulation and secretion. It is not always easy to distinguish between short- and long-term signalling. For example, adenosine triphosphate (ATP) can sometimes act as a short-term trigger for long-term trophic events that become evident days or even weeks after the original challenge. Examples of short-term purinergic signalling during sympathetic, parasympathetic and enteric neuromuscular transmission and in synaptic transmission in ganglia and in the central nervous system are described, as well as in neuromodulation and secretion. Long-term trophic signalling is described in the immune/defence system, stratified epithelia in visceral organs and skin, embryological development, bone formation and resorption and in cancer. It is likely that the increase in intracellular Ca(2+) in response to both P2X and P2Y purinoceptor activation participates in many short- and long-term physiological effects.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'.
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Affiliation(s)
- Geoffrey Burnstock
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Victoria, Australia
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Burnstock G. An introduction to the roles of purinergic signalling in neurodegeneration, neuroprotection and neuroregeneration. Neuropharmacology 2015; 104:4-17. [PMID: 26056033 DOI: 10.1016/j.neuropharm.2015.05.031] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 12/21/2022]
Abstract
Purinergic signalling appears to play important roles in neurodegeneration, neuroprotection and neuroregeneration. Initially there is a brief summary of the background of purinergic signalling, including release of purines and pyrimidines from neural and non-neural cells and their ectoenzymatic degradation, and the current characterisation of P1 (adenosine), and P2X (ion channel) and P2Y (G protein-coupled) nucleotide receptor subtypes. There is also coverage of the localization and roles of purinoceptors in the healthy central nervous system. The focus is then on the roles of purinergic signalling in trauma, ischaemia, stroke and in neurodegenerative diseases, including Alzheimer's, Parkinson's and Huntington's diseases, as well as multiple sclerosis and amyotrophic lateral sclerosis. Neuroprotective mechanisms involving purinergic signalling are considered and its involvement in neuroregeneration, including the role of adult neural stem/progenitor cells. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London NW3 2PF, UK; Department of Pharmacology and Therapeutics, The University of Melbourne, Australia.
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Introduction to Purinergic Signalling in the Brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 986:1-12. [DOI: 10.1007/978-94-007-4719-7_1] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Zhao YD, Cheng SY, Ou S, Xiao Z, He WJ, Jian-Cui, Ruan HZ. Effect of hypobaric hypoxia on the P2X receptors of pyramidal cells in the immature rat hippocampus CA1 sub-field. Brain Inj 2012; 26:282-90. [PMID: 22372415 DOI: 10.3109/02699052.2011.650665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PRIMARY OBJECTIVE This study was designed to evaluate the effect of hypobaric hypoxia (HH) on the function and expression of P2X receptors in rat hippocampus CA1 pyramidal cells. RESEARCH DESIGN The functional changes of P2X receptors were investigated through the cell HH model and the expressional alterations of P2X receptors were observed through the animal HH model. METHODS AND PROCEDURE P2X receptors mediated currents were recorded from the freshly dissociated CA1 pyramidal cells of 7-day-old SD rats by whole cell patch clamp recording. The expression and distribution of P2X receptors were observed through immunohistochemistry and western blot at HH 3-day and 7-day. MAIN OUTCOMES AND RESULTS In acute HH conditions, the amplitudes of ATP evoked peak currents were decreased compared to control. The immunohistochemistry and western blot results reflected there was no change in P2X receptors expression after 3 days HH injury, while P2X receptors expression was up-regulated in response to 7 days HH injury. CONCLUSIONS These findings supported the possibility that the function of P2X receptors was sensitive to HH damage and long-term function decrease should result in the expression increase of P2X receptors.
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Affiliation(s)
- Yan-Dong Zhao
- Department of Neurobiology, College of Basic Medical Sciences, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, PR China
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Lalo U, Verkhratsky A, Burnstock G, Pankratov Y. P2X receptor-mediated synaptic transmission. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/wmts.28] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Burnstock G, Krügel U, Abbracchio MP, Illes P. Purinergic signalling: from normal behaviour to pathological brain function. Prog Neurobiol 2011; 95:229-74. [PMID: 21907261 DOI: 10.1016/j.pneurobio.2011.08.006] [Citation(s) in RCA: 315] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 08/12/2011] [Accepted: 08/15/2011] [Indexed: 02/07/2023]
Abstract
Purinergic neurotransmission, involving release of ATP as an efferent neurotransmitter was first proposed in 1972. Later, ATP was recognised as a cotransmitter in peripheral nerves and more recently as a cotransmitter with glutamate, noradrenaline, GABA, acetylcholine and dopamine in the CNS. Both ATP, together with some of its enzymatic breakdown products (ADP and adenosine) and uracil nucleotides are now recognised to act via P2X ion channels and P1 and P2Y G protein-coupled receptors, which are widely expressed in the brain. They mediate both fast signalling in neurotransmission and neuromodulation and long-term (trophic) signalling in cell proliferation, differentiation and death. Purinergic signalling is prominent in neurone-glial cell interactions. In this review we discuss first the evidence implicating purinergic signalling in normal behaviour, including learning and memory, sleep and arousal, locomotor activity and exploration, feeding behaviour and mood and motivation. Then we turn to the involvement of P1 and P2 receptors in pathological brain function; firstly in trauma, ischemia and stroke, then in neurodegenerative diseases, including Alzheimer's, Parkinson's and Huntington's, as well as multiple sclerosis and amyotrophic lateral sclerosis. Finally, the role of purinergic signalling in neuropsychiatric diseases (including schizophrenia), epilepsy, migraine, cognitive impairment and neuropathic pain will be considered.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London NW3 2PF, UK.
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Pankratov Y, Lalo U, Krishtal OA, Verkhratsky A. P2X receptors and synaptic plasticity. Neuroscience 2008; 158:137-48. [PMID: 18495357 DOI: 10.1016/j.neuroscience.2008.03.076] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 03/09/2008] [Accepted: 03/17/2008] [Indexed: 01/15/2023]
Abstract
Adenosine triphosphate (ATP) is released in many synapses in the CNS either together with other neurotransmitters, such as glutamate and GABA, or on its own. Postsynaptic action of ATP is mediated through metabotropic P2Y and ionotropic P2X receptors abundantly expressed in neural cells. Activation of P2X receptors induces fast excitatory postsynaptic currents in synapses located in various brain regions, including medial habenula, hippocampus and cortex. P2X receptors display relatively high Ca2+ permeability and can mediate substantial Ca2+ influx at resting membrane potential. P2X receptors can dynamically interact with other neurotransmitter receptors, including N-methyl-D-aspartate (NMDA) receptors, GABA(A) receptors and nicotinic acetylcholine (ACh) receptors. Activation of P2X receptors has multiple modulatory effects on synaptic plasticity, either inhibiting or facilitating the long-term changes of synaptic strength depending on physiological context. At the same time precise mechanisms of P2X-dependent regulation of synaptic plasticity remain elusive. Further understanding of the role of P2X receptors in regulation of synaptic transmission in the CNS requires dissection of P2X-mediated effects on pre-synaptic terminals, postsynaptic membrane and glial cells.
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Affiliation(s)
- Y Pankratov
- The University of Warwick, Department of Biological Sciences, Gibbet Hill Road, Coventry CV4 7AL, UK
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Kondratskaya E, Nonaka K, Akaike N. Influence of purinergic modulators on eEPSCs in rat CA3 hippocampal neurons: Contribution of ionotropic ATP receptors. NEUROPHYSIOLOGY+ 2008. [DOI: 10.1007/s11062-008-9011-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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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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Pankratov Y, Lalo U, Verkhratsky A, North RA. Vesicular release of ATP at central synapses. Pflugers Arch 2006; 452:589-97. [PMID: 16639550 DOI: 10.1007/s00424-006-0061-x] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2006] [Accepted: 03/06/2006] [Indexed: 12/21/2022]
Abstract
Adenosine triphosphate (ATP) acts as a fast excitatory transmitter in several regions of the central nervous system (CNS) including the medial habenula, dorsal horn, locus coeruleus, hippocampus, and somatosensory cortex. Postsynaptic actions of ATP are mediated through an extended family of P2X receptors, widely expressed throughout the CNS. ATP is released via several pathways, including exocytosis from presynaptic terminals and diffusion through large transmembrane pores (e.g., hemichannels, P2X(7) receptors, or volume-sensitive chloride channels) expressed in astroglial membranes. In presynaptic terminals, ATP is accumulated and stored in the synaptic vesicles. In different presynaptic terminals, these vesicles may contain ATP only or ATP and another neurotransmitter [e.g., gamma-amino-butyric acid (GABA) or glutamate]; in the latter case, two transmitters can be coreleased. Here, we discuss the mechanisms of vesicular release of ATP in the CNS and present our own data, which indicate that in central neuronal terminals, ATP is primarily stored and released from distinct pool of vesicles; the release of ATP is not synchronized either with GABA or with glutamate.
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Affiliation(s)
- Yuri Pankratov
- Faculty of Life Sciences, The University of Manchester, 1.124 Stopford Building, Oxford Road, Manchester, M13 9PT, UK
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Dulla CG, Dobelis P, Pearson T, Frenguelli BG, Staley KJ, Masino SA. Adenosine and ATP link PCO2 to cortical excitability via pH. Neuron 2005; 48:1011-23. [PMID: 16364904 PMCID: PMC1924599 DOI: 10.1016/j.neuron.2005.11.009] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Revised: 08/11/2005] [Accepted: 11/05/2005] [Indexed: 11/28/2022]
Abstract
In addition to affecting respiration and vascular tone, deviations from normal CO(2) alter pH, consciousness, and seizure propensity. Outside the brainstem, however, the mechanisms by which CO(2) levels modify neuronal function are unknown. In the hippocampal slice preparation, increasing CO(2), and thus decreasing pH, increased the extracellular concentration of the endogenous neuromodulator adenosine and inhibited excitatory synaptic transmission. These effects involve adenosine A(1) and ATP receptors and depend on decreased extracellular pH. In contrast, decreasing CO(2) levels reduced extracellular adenosine concentration and increased neuronal excitability via adenosine A(1) receptors, ATP receptors, and ecto-ATPase. Based on these studies, we propose that CO(2)-induced changes in neuronal function arise from a pH-dependent modulation of adenosine and ATP levels. These findings demonstrate a mechanism for the bidirectional effects of CO(2) on neuronal excitability in the forebrain.
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Affiliation(s)
- Chris G Dulla
- Neuroscience Program, Department of Neurology, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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Kim DS, Kwak SE, Kim JE, Won MH, Suh JG, Oh YS, Kang TC. The effect of P2X receptor activity on GABAA receptor-mediated inhibition in the gerbil hippocampus. Brain Res 2005; 1065:125-31. [PMID: 16309634 DOI: 10.1016/j.brainres.2005.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Revised: 09/28/2005] [Accepted: 10/03/2005] [Indexed: 11/20/2022]
Abstract
In the present study, to elucidate the effect of altered P(2)X receptor transmission on GABA(A) receptor expression and its transmission, we studied the morphological and electrophysiological responses of GABA(A) receptor in the gerbil hippocampus following P(2)X receptor antagonist/agonist treatment. Suramin or pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) treatment did not affect GABA(A) receptor immunoreactivities and paired-pulse responses in the gerbil hippocampus. In addition, ATP treatment did not significantly affect population spike amplitude ratios and EPSP slope ratios in the gerbil dentate gyrus. Co-application, but not pretreatment, of PPADS or suramin enhanced the effect of muscimol on paired-pulse inhibition in the dentate gyrus. In contrast, co-application of ATP reduced the effect of muscimol in the dentate gyrus. These findings indicate that the blockade of P(2)X receptor did not affect GABA(A) receptor immunoreactivities, and P(2)X receptor may modulate GABA(A) receptor-mediated inhibition when in co-activation with GABA(A) receptor. Therefore, our findings suggest that the relationship between GABA(A) receptor and P(2)X receptor may not be reciprocal, although GABA(A) receptor activity affects P(2)X receptor functionality and its expression.
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Affiliation(s)
- Duk-Soo Kim
- Department of Anatomy, College of Medicine, Hallym University, Chunchon, Kangwon-Do 200-702, South Korea
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Franke H, Illes P. Involvement of P2 receptors in the growth and survival of neurons in the CNS. Pharmacol Ther 2005; 109:297-324. [PMID: 16102837 DOI: 10.1016/j.pharmthera.2005.06.002] [Citation(s) in RCA: 189] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Accepted: 06/06/2005] [Indexed: 12/12/2022]
Abstract
Extracellular adenosine 5'-triphosphate (ATP) has been recognized as a ubiquitous, unstable signalling molecule, acting as a fast neurotransmitter and modulator of transmitter release and neuronal excitability. Recent findings have demonstrated that ATP is a growth factor participating in differentiation, cell proliferation, and survival, as well as a toxic agent that mediates cellular degeneration and death. Potential sources of extracellular purines in the nervous system include neurons, glia, endothelium, and blood. A complex family of ectoenzymes rapidly hydrolyzes or interconverts extracellular nucleotides, thereby either terminating their signalling action or producing an active metabolite of altered purinoceptor selectivity. Most effects are mediated through the 2 main subclasses of specific cell surface receptors, P2X and P2Y. Members of these P2X/Y receptor families are widely expressed in the central nervous system (CNS) and are involved in glia-glia and glia-neuron communications, whereby they play important physiological and pathophysiological roles in a variety of biological processes. After different kinds of "acute" CNS injury (e.g., ischemia, hypoxia, mechanical stress, axotomy), extracellular ATP can reach high concentrations, up to the millimolar range, flowing out from cells into the extracellular space, exocytotically, via transmembrane transport, or as a result of cell damage. In this review, P2 receptor activation as a cause or a consequence of neuronal cell activation or death and/or glial activation is described. The involvement of P2 receptors is also described under different "chronic" pathological conditions, such as pain, epilepsia, toxic influence of ethanol or amphetamine, retinal diseases, Alzheimer's disease (AD), and possibly, Parkinson's disease. The relationship between changes in P2 receptor expression and the specific response of different cell types to injury is extremely complex and can be related to detrimental and/or beneficial effects. The present review therefore considers ATP acting via P2 receptors as a potent regulator of normal physiological and pathological processes in the brain, with a focus on pathophysiological implications of P2 receptor functions.
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Affiliation(s)
- Heike Franke
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, Härtelstrasse 16-18, D-04107, Leipzig, Germany.
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Fujii S. ATP- and adenosine-mediated signaling in the central nervous system: the role of extracellular ATP in hippocampal long-term potentiation. J Pharmacol Sci 2004; 94:103-6. [PMID: 14978345 DOI: 10.1254/jphs.94.103] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Application of 10 microM ATP for 10 min transiently depressed, then slowly augmented, synaptic transmission in CA1 neurons, leading to long-term potentiation (LTP) (ATP-induced LTP). This ATP-induced LTP was blocked by addition of an N-methyl-D-aspartate (NMDA) glutamate receptor antagonist, D,L-2-amino-5-phosphonovalerate (5 microM). For ATP-induced LTP, delivery of test synaptic inputs once every 20 s to CA1 neurons could be substituted by application of 100 nM NMDA during ATP perfusion. In addition, ATP-induced LTP was blocked by co-application of an ecto-protein kinase inhibitor, K-252b (40 nM), whereas a P2X purinoceptor antagonist, pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid 4-sodium (50 microM), or a P2Y purinoceptor antagonist, basilen blue (10 microM), had no effect. These results, therefore, indicate that the mechanisms of ATP-induced LTP involve the modulation of NMDA receptors / Ca(2+) channels and the phosphorylation of extracellular domains of synaptic membrane proteins, one of which could be the NMDA receptor / Ca(2+) channel.
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Affiliation(s)
- Satoshi Fujii
- Department of Physiology, Yamagata University School of Medicine, Japan.
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Kang TC, Park SK, Hwang IK, An SJ, Won MH. GABA(B) receptor-mediated regulation of P2X7 receptor expression in the gerbil hippocampus. ACTA ACUST UNITED AC 2004; 121:12-8. [PMID: 14969732 DOI: 10.1016/j.molbrainres.2003.10.020] [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] [Accepted: 10/07/2003] [Indexed: 11/30/2022]
Abstract
In the present study, the P(2)X(7) receptor expression in the gerbil hippocampus and GABA-mediated responses of its expression was investigated in order to identify the roles of the P(2)X(7) receptor on seizure activity and recovery mechanisms. P(2)X(7) receptor immunoreactivity in seizure-resistant (SR) gerbils was similar to that in pre-seizure group of seizure-sensitive (SS) gerbils. The administration of baclofen, a GABA(B) receptor agonist, P(2)X(7) receptor immunoreactivity was decreased in the mossy fiber, compared with that of non-treated gerbils, whereas treatment with phaclofen, a GABA(B) receptor antagonist, elevated P(2)X(7) receptor expression. Neither the treatments with GABA(A) receptor agonist nor antagonist affected P(2)X(7) receptor expression in the hippocampus. These findings suggest that altered P(2)X(7) receptor expression may not be involved in the epileptogenesis or seizure activity in gerbils, and presynaptic GABA(B) receptor-mediated actions may be closely related with the regulation of P(2)X(7) receptor expression in the gerbil hippocampus.
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Affiliation(s)
- Tae-Cheon Kang
- Department of Anatomy, College of Medicine, Hallym University, Chunchon, Kangwon-Do 200-702, South Korea.
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Burnstock G, Knight GE. Cellular Distribution and Functions of P2 Receptor Subtypes in Different Systems. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 240:31-304. [PMID: 15548415 DOI: 10.1016/s0074-7696(04)40002-3] [Citation(s) in RCA: 581] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review is aimed at providing readers with a comprehensive reference article about the distribution and function of P2 receptors in all the organs, tissues, and cells in the body. Each section provides an account of the early history of purinergic signaling in the organ?cell up to 1994, then summarizes subsequent evidence for the presence of P2X and P2Y receptor subtype mRNA and proteins as well as functional data, all fully referenced. A section is included describing the plasticity of expression of P2 receptors during development and aging as well as in various pathophysiological conditions. Finally, there is some discussion of possible future developments in the purinergic signaling field.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Institute, Royal Free and University College Medical School, London NW3 2PF, United Kingdom
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Yamazaki Y, Kaneko K, Fujii S, Kato H, Ito KI. Long-term potentiation and long-term depression induced by local application of ATP to hippocampal CA1 neurons of the guinea pig. Hippocampus 2003; 13:81-92. [PMID: 12625460 DOI: 10.1002/hipo.7999] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The present study has investigated the role of ATP in the induction of synaptic plasticity, using local application of ATP by picopump administration into the stratum radiatum of guinea pig hippocampal region CA1. Excitatory postsynaptic currents (EPSCs) evoked by stimulation of Schaffer collateral/commissural afferents synapsing on CA1 pyramidal cells of hippocampal slices were monitored in voltage-clamp mode, using whole-cell recording. Brief local application of ATP (1 mM) induced an inward current, usually consisting of early- and late-phase components. Because the late-phase component of an ATP-induced current was largely inhibited by Ca2+-free solution, this component is supposed to depend on extracellular Ca2+. After local application of ATP, long-term synaptic modification of EPSCs was induced: LTP was detected in neurons exhibiting a small late Ca2+ current, while LTD was obtained from recordings showing a large late Ca2+ current in response to ATP application. There was a statistically significant correlation between the magnitude of long-term plastic changes and the size of Ca2+ currents in response to ATP application. Furthermore, there was significant difference between the average size of the Ca2+ current in the LTP group and the size in the LTD group. These results suggest that a small Ca2+ influx in response to ATP application induces LTP, whereas a large one induces LTD in guinea pig hippocampal CA1 neurons.
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Affiliation(s)
- Yoshihiko Yamazaki
- Department of Physiology, Yamagata University School of Medicine, Yamagata, Japan
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24
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Florenzano F, Viscomi MT, Cavaliere F, Volonté C, Molinari M. Cerebellar lesion up-regulates P2X1 and P2X2 purinergic receptors in precerebellar nuclei. Neuroscience 2003; 115:425-34. [PMID: 12421608 DOI: 10.1016/s0306-4522(02)00397-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
ATP released in the extracellular space by neuronal injury can influence neighboring neurons via activation of purinergic receptors. In vitro data suggest the involvement of ATP and purinergic receptors as trophic agents in different biological events such as neuritogenesis and cell survival. Recently, in vivo studies have demonstrated modifications in the glial expression of ionotropic purinergic receptors after CNS lesions. In the present study, we investigated the effects of CNS lesion on the neuronal expression of P2X(1) and P2X(2) receptor subunits by immunohistochemistry and western blotting techniques. In the precerebellar structures of normal animals the expression of P2X(1) and P2X(2) was lower than previously reported. P2X(1) immunostaining was confined only to fibers, while P2X(2) immunostaining demonstrated a neuronal expression. After unilateral cerebellar lesion (hemicerebellectomy) axotomized precerebellar neurons underwent marked cell loss; however, some precerebellar neurons did not degenerate. Seven to 35 days after hemicerebellectomy, a transient, time-dependent, marked increase in the number of immunopositive P2X(1) and P2X(2) neurons was observed in the precerebellar nuclei of the experimental side. An even distribution of immunopositive neurons was present in almost all precerebellar nuclei examined, except for the inferior olive. In this latter structure, differences in the distribution of immunopositive neurons were evident among the subnuclei. Up-regulation of immunoreactivity over relatively long time periods, distribution selectivity and absence of degenerating morphological features in immunopositive neurons suggest that purinergic receptors may have a role in mediating the survival of neuronal responses to axotomy. The present findings are the first report in the CNS of P2X(1) and P2X(2) receptor subunit involvement in neuronal reaction to axotomy. They provide in vivo evidence of a correlation between purinergic receptor subunit up-regulation and survival of injured neurons.
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Affiliation(s)
- F Florenzano
- I.R.C.C.S. Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy
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25
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Fujii S, Kato H, Kuroda Y. Cooperativity between extracellular adenosine 5'-triphosphate and activation of N-methyl-D-aspartate receptors in long-term potentiation induction in hippocampal CA1 neurons. Neuroscience 2002; 113:617-28. [PMID: 12150781 DOI: 10.1016/s0306-4522(02)00190-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The mechanism of ATP-induced long-term potentiation (LTP) was studied pharmacologically using guinea-pig hippocampal slices. LTP, induced in CA1 neurons by 10 min application of 10 microM ATP, was blocked by co-application of the N-methyl-D-aspartate (NMDA) receptor antagonist, D,L-2-amino-5-phosphonovalerate (5 or 50 microM). In ATP-induced LTP, the delivery of test synaptic inputs (once every 20 s) to CA1 neurons could be replaced by co-application of NMDA (100 nM) during ATP perfusion. These results suggest that, in CA1 neurons, a co-operative effect between extracellular ATP and activation of NMDA receptors is required to trigger the process involved in ATP-induced LTP. In addition, ATP-induced LTP was blocked by co-application of an ecto-protein kinase inhibitor, K-252b (40 or 200 nM), whereas a P2X purinoceptor antagonist, pyridoxal phosphate 6-azophenyl-2',4'-disulfonic acid 4-sodium (50 microM), or a P2Y purinoceptor antagonist, basilen blue (10 microM), had no effect.The results of the present study, therefore, indicate that the mechanisms of ATP-induced LTP involve the modulation of NMDA receptors/Ca(2+) channels and the phosphorylation of extracellular domains of synaptic membrane proteins, one of which could be the NMDA receptor/Ca(2+) channel.
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Affiliation(s)
- S Fujii
- Department of Physiology,Yamagata University School of Medicine,Yamagata 990-9585, Japan.
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27
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Abstract
P2X receptors are membrane ion channels that open in response to the binding of extracellular ATP. Seven genes in vertebrates encode P2X receptor subunits, which are 40-50% identical in amino acid sequence. Each subunit has two transmembrane domains, separated by an extracellular domain (approximately 280 amino acids). Channels form as multimers of several subunits. Homomeric P2X1, P2X2, P2X3, P2X4, P2X5, and P2X7 channels and heteromeric P2X2/3 and P2X1/5 channels have been most fully characterized following heterologous expression. Some agonists (e.g., alphabeta-methylene ATP) and antagonists [e.g., 2',3'-O-(2,4,6-trinitrophenyl)-ATP] are strongly selective for receptors containing P2X1 and P2X3 subunits. All P2X receptors are permeable to small monovalent cations; some have significant calcium or anion permeability. In many cells, activation of homomeric P2X7 receptors induces a permeability increase to larger organic cations including some fluorescent dyes and also signals to the cytoskeleton; these changes probably involve additional interacting proteins. P2X receptors are abundantly distributed, and functional responses are seen in neurons, glia, epithelia, endothelia, bone, muscle, and hemopoietic tissues. The molecular composition of native receptors is becoming understood, and some cells express more than one type of P2X receptor. On smooth muscles, P2X receptors respond to ATP released from sympathetic motor nerves (e.g., in ejaculation). On sensory nerves, they are involved in the initiation of afferent signals in several viscera (e.g., bladder, intestine) and play a key role in sensing tissue-damaging and inflammatory stimuli. Paracrine roles for ATP signaling through P2X receptors are likely in neurohypophysis, ducted glands, airway epithelia, kidney, bone, and hemopoietic tissues. In the last case, P2X7 receptor activation stimulates cytokine release by engaging intracellular signaling pathways.
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Affiliation(s)
- R Alan North
- Institute of Molecular Physiology, University of Sheffield, Western Bank, Sheffield, United Kingdom.
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28
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Abstract
ATP receptors participate in synaptic transmission and intracellular calcium signaling in the hippocampus by providing a component of the excitatory input to CA1 pyramidal neurons. The activation of P2X purinoreceptors generates calcium influx that does not require cell depolarization, but this response desensitizes at increased rates of stimulation. Here we show that inhibition of P2X receptors dramatically facilitates the induction of long-term potentiation (LTP). High-frequency stimulation (HFS) (1 sec) induced LTP in CA1, whereas brief HFS (0.2 sec) caused only short-term potentiation. However, when P2X receptors were inhibited by PPADS (pyridoxal phosphate-6-azophenyl-2'-4'-disulphonic acid) or desensitized by the nonhydrolyzable ATP analog alpha,beta-methyleneATP, brief HFS reliably induced LTP. Inhibition of P2X receptors had no facilitatory effect on LTP when NMDA receptors were blocked. We hypothesized that P2X receptors affect the threshold for LTP by altering Ca2+-dependent inactivation of NMDA receptors. In isolated pyramidal CA1 neurons and hippocampal slices, activation of P2X receptors did cause inhibition of NMDA receptor-mediated current. We suggest that, by controlling the background calcium and thus the activity of NMDA receptors at low firing frequencies, P2X receptors act as a dynamic low-frequency filter so that weak stimuli do not induce LTP.
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Amadio S, D'Ambrosi N, Cavaliere F, Murra B, Sancesario G, Bernardi G, Burnstock G, Volonté C. P2 receptor modulation and cytotoxic function in cultured CNS neurons. Neuropharmacology 2002; 42:489-501. [PMID: 11955520 DOI: 10.1016/s0028-3908(01)00197-6] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In this study we investigate the presence, modulation and biological function of P2 receptors and extracellular ATP in cultured cerebellar granule neurons. As we demonstrate by RT-PCR and western blotting, both P2X and P2Y receptor subtypes are expressed and furthermore regulated as a function of neuronal maturation. In early primary cultures, mRNA for most of the P2 receptor subtypes, except P2X(6), are found, while in older cultures only P2X(3), P2Y(1) and P2Y(6) mRNA persist. In contrast, P2 receptor proteins are more prominent in mature neurons, with the exception of P2Y(1). We also report that extracellular ATP acts as a cell death mediator for fully differentiated and mature granule neurons, for dissociated striatal primary cells and hippocampal organotypic cultures, inducing both apoptotic and necrotic features of degeneration. ATP causes cell death with EC(50) in the 20-50 microM range within few minutes of exposure and with a time lapse of at most two hours. Additional agonists for P2 receptors induce toxic effects, whereas selected antagonists are protective. Cellular swelling, lactic dehydrogenase release and nuclei fragmentation are among the features of ATP-evoked cell death, which also include direct P2 receptor modulation. Comparably to P2 receptor antagonists previously shown preventing glutamate-toxicity, here we report that competitive and non-competitive NMDA receptor antagonists inhibit the detrimental consequences of extracellular ATP. Due to the massive extracellular release of purine nucleotides and nucleosides often occurring during a toxic insult, our data indicate that extracellular ATP can now be included among the potential causes of CNS neurodegenerative events.
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Affiliation(s)
- S Amadio
- Fondazione Santa Lucia, Via Ardeatina 354, 00179, Rome, Italy
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30
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Abstract
P2X receptors are a family of ligand-gated ion channels, activated by extracellular ATP. The seven subunits cloned (P2X1-7) can assemble to form homomeric and heteromeric receptors. Peripheral neurons of neural crest origin (e.g. those in dorsal root, trigeminal, sympathetic and enteric ganglia) and placodal origin (e.g. those in nodose and petrosal ganglia) express mRNAs for multiple P2X subunits. In this review, we summarize the molecular biological, electrophysiological and immunohistochemical evidence for P2X receptor subunits in sensory, sympathetic, parasympathetic, pelvic and myenteric neurons and adrenomedullary chromaffin cells. We consider the pharmacological properties of these native P2X receptors and their physiological roles. The responses of peripheral neurons to ATP show considerable heterogeneity between cells in the same ganglia, between ganglia and between species. Nevertheless, these responses can all be accounted for by the presence of P2X2 and P2X3 subunits, giving rise to varying proportions of homomeric and heteromeric receptors. While dorsal root ganglion neurons express predominantly P2X3 and rat sympathetic neurons express mainly P2X2 receptors, nodose and guinea-pig sympathetic neurons express mixed populations of P2X2 and heteromeric P2X2/3 receptors. P2X receptors are important for synaptic transmission in enteric ganglia, although their roles in sympathetic and parasympathetic ganglia are less clear. Their presence on sensory neurons is essential for some processes including detection of filling of the urinary bladder. The regulation of P2X receptor expression in development and in pathological conditions, along with the interactions between purinergic and other signalling systems, may reveal further physiological roles for P2X receptors in autonomic and sensory ganglia.
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Affiliation(s)
- P M Dunn
- Autonomic Neuroscience Institute, Royal Free and University College Medical School, Rowland Hill Street, NW3 2PF, London, UK
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31
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Schools GP, Kimelberg HK. Metabotropic glutamate receptors in freshly isolated astrocytes from rat hippocampus. PROGRESS IN BRAIN RESEARCH 2001; 132:301-12. [PMID: 11544998 DOI: 10.1016/s0079-6123(01)32084-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- G P Schools
- Center for Neuropharmacology and Neuroscience, Albany Medical College, MC-136, 47 New Scotland Avenue, Albany, NY 12208, USA
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Ueno T, Ueno S, Kakazu Y, Akaike N, Nabekura J. Bidirectional modulation of P2X receptor-mediated response by divalent cations in rat dorsal motor nucleus of the vagus neurons. J Neurochem 2001; 78:1009-18. [PMID: 11553675 DOI: 10.1046/j.1471-4159.2001.00473.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The modulatory effects of Zn(2+) and other divalent cations on the ATP-induced responses of preganglionic neurons acutely dissociated from the rat dorsal motor nucleus of the vagus (DMV) were examined using a nystatin-perforated patch technique under voltage-clamp. DMV neurons were identified by back-filling of DiI placed on the vagal bundle at the neck. Zn(2+) exerts a concentration-dependent effect on P2X receptor-mediated current (I(ATP)): a potentiation by low concentrations of Zn(2+) (< or = 50 microM) and an inhibition by high concentrations (> 50 microM). Inhibition of the ATP response was associated with a prolongation of the rising phase of I(ATP). Cu(2+) mimicked Zn(2+) regarding the biphasic modulation of I(ATP). On the other hand, Ni(2+) potentiated, but failed to inhibit, the ATP response even at a concentration of 3 mM. Quantitative RT-PCR revealed the similarity of P2X(2) mRNA expression between the DMV and superior cervical ganglion (SCG) but not in the dorsal root ganglion (DRG) and hypoglossal nucleus (XII). The results from the electrophysiological and molecular approaches suggest that functional P2X receptors expressed in DMV neurons are characterized mainly by the P2X(2) and P2X(2/6) subtype. DMV neurons possess similar P2X receptor characteristics to SCG neurons.
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Affiliation(s)
- T Ueno
- Department of Cellular and System Physiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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33
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Abstract
ATP mediates fast excitatory synaptic transmission in some regions of the central nervous system through activation of P2X receptors. Nonetheless, the functional significance of ATP-mediated neurotransmission is not yet understood. Using postembedding immunocytochemistry, we describe the distribution of P2X(2), P2X(4), and P2X(6) subunits in cerebellum and in the CA1 region of the hippocampus. Dendritic spines of cerebellar Purkinje cells showed immunogold labeling for all three subunits when apposed to parallel fiber (PF) terminals. In contrast, no immunogold labeling was observed on dendritic spines or cell bodies receiving inputs from climbing fibers and basket cells, respectively. In CA1 pyramidal cells, postsynaptic membranes apposed to terminals of Schaffer collaterals were immunogold-labeled for P2X(2), P2X(4), and P2X(6) subunits. Immunolabeling was also observed perisynaptically and intracellularly in relation to membranes of the endoplasmic reticulum. The analysis of the tangential distribution of gold particles showed that they were preferentially located at the peripheral portion of the postsynaptic specialization of both parallel fiber and Schaffer collateral synapses. By double imunogold labeling using antibodies for P2X receptor subunits and GluR2/3 subunits of the AMPA glutamate receptors, we show that synapses expressing P2X receptors are also glutamatergic. The present study shows for the first time qualitatively and quantitatively the precise localization of P2X receptors in brain. Moreover, our data indicate that P2X receptors may play a significant role at glutamatergic synapses.
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Li C, Xiong K, Weight FF. Ethanol inhibition of adenosine 5'-triphosphate-activated current in freshly isolated adult rat hippocampal CA1 neurons. Neurosci Lett 2000; 295:77-80. [PMID: 11090978 DOI: 10.1016/s0304-3940(00)01586-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effect of ethanol on current activated by extracellular adenosine 5'-triphosphate (ATP) was studied in freshly isolated adult rat hippocampal CA1 neurons using whole-cell patch-clamp recording. ATP activated an inward current with an EC(50) value of 18 microM. The inward current was also activated by 2-methylthio ATP (2-MeSATP) and alpha,beta-methylene ATP (alpha,beta-MeATP), inhibited by pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), and potentiated by Zn(2+). Ethanol inhibited current activated by 10 microM ATP with an IC(50) value of 83 mM in a voltage-independent manner. Ethanol, 100 mM, shifted the ATP concentration-response curve to the right, increasing the EC(50) value for ATP from 18 to 33 microM, but did not reduce the maximal response to ATP. The results suggest that ethanol can inhibit the function of P2X receptors in adult rat hippocampal neurons by decreasing the apparent affinity of the binding site for ATP.
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Affiliation(s)
- C Li
- Laboratory of Molecular and Cellular Neurobiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, MD 20892-8115, Bethesda, USA.
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36
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O'Kane EM, Stone TW. Characterisation of ATP-induced facilitation of transmission in rat hippocampus. Eur J Pharmacol 2000; 409:159-66. [PMID: 11104829 DOI: 10.1016/s0014-2999(00)00785-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Superfusion of rat hippocampal slices with ATP induces a form of facilitation that has been poorly characterised. The present study has confirmed that at low concentrations of ATP (10 microM or less), an initial depression of evoked potential size is followed by a rebound facilitation which is not reproduced by alphabeta-methyleneATP, betagamma-methyleneATP, or the dinucleotide P1,P6-diadenosine hexaphosphate. The post-ATP facilitation could be prevented by the adenosine A1 receptor antagonists 8-phenyltheophylline or 1,3-dipropyl-8-cyclopentyltheophylline (50 nM), or superfusion of adenosine deaminase. The adenosine A2A receptor antagonist 8-(chlorostyryl)-caffeine did not affect the inhibition but prevented the post-ATP facilitation. The NMDA receptor antagonist 2-amino-5-phosphonopentanoic acid prevented the establishment of post-ATP facilitation. The post-ATP facilitation was also blocked by suramin at a concentration (50 microM) that does not block glutamate receptors. Suramin prevented the induction but not the maintenance phase of the post-ATP facilitation. The repeated induction of post-ATP facilitation by bursts of electrical stimulation designed to saturate the normal mechanisms of long-term potentiation prevented the induction of post-ATP facilitation. However, repeated applications of ATP to achieve saturation of its receptor did not prevent the subsequent induction of electrically evoked long-term potentiation. It is concluded that ATP can induce a form of synaptic facilitation which resembles only partially that induced by electrical stimulation and which may require the simultaneous activation of P1 and P2 receptors.
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Affiliation(s)
- E M O'Kane
- Institute of Biomedical and Life Sciences, West Medical Building, University of Glasgow, Glassgow G12 8QQ, Scotland, UK
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Pintor J, Díaz-Hernández M, Gualix J, Gómez-Villafuertes R, Hernando F, Miras-Portugal MT. Diadenosine polyphosphate receptors. from rat and guinea-pig brain to human nervous system. Pharmacol Ther 2000; 87:103-15. [PMID: 11007994 DOI: 10.1016/s0163-7258(00)00049-8] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Diadenosine polyphosphates are a family of naturally occurring nucleotidic compounds present in secretory vesicles together with other chemical messengers. The exocytotic release of these compounds permits them to stimulate receptors termed "purinoceptors" or "ATP receptors." Purinoceptors for nucleotides are named P2 in contrast with those sensitive to nucleosides (P1). P2 receptors are further subdivided into metabotropic P2Y receptors, further divided into 5 subtypes, and ionotropic P2X receptors, with 7 different subtypes. Diadenosine polyphosphates can activate recombinant P2Y(1), P2Y(2), and P2Y(4) and recombinant homomeric P2X(1), P2X(2), P2X(3), P2X(4), and P2X(6). Heteromeric P2X receptors change their sensitivity to diadenosine polyphosphates when co-assembly between different subunits occurs. Diadenosine polyphosphates can activate specific receptors termed dinucleotide receptors or P4 receptors, which are insensitive to other nucleosides or nucleotides. The P4 receptor is a receptor-operated Ca(2)+ channel present in rat brain synaptic terminals, stimulated by diadenosine pentaphosphate and diadenosine tetraphosphate. This receptor is strongly modulated by protein kinases A and C and protein phosphatases. The dinucleotide receptor is present in different brain areas, such as midbrain (in rat and guinea-pig), cerebellum (in guinea-pig), and cortex (in human).
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Affiliation(s)
- J Pintor
- Departamento de Bioquímica y Biología Molecular IV, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040, Madrid, Spain.
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