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Ferré S, Díaz-Ríos M, Salamone JD, Prediger RD. New Developments on the Adenosine Mechanisms of the Central Effects of Caffeine and Their Implications for Neuropsychiatric Disorders. J Caffeine Adenosine Res 2018; 8:121-131. [PMID: 30596206 PMCID: PMC6306650 DOI: 10.1089/caff.2018.0017] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Recent studies on interactions between striatal adenosine and dopamine and one of its main targets, the adenosine A2A receptor–dopamine D2 receptor (A2AR–D2R) heteromer, have provided a better understanding of the mechanisms involved in the psychostimulant effects of caffeine and have brought forward new data on the mechanisms of operation of classical orthosteric ligands within G protein-coupled receptor heteromers. The striatal A2AR–D2R heteromer has a tetrameric structure and forms part of a signaling complex that includes a Gs and a Gi protein and the effector adenyl cyclase (subtype AC5). Another target of caffeine, the adenosine A1 receptor–dopamine D1 receptor (A1R–D1R) heteromer, seems to have a very similar structure. Initially suggested to be localized in the striatum, the A1R–D1R heteromer has now been identified in the spinal motoneuron and shown to mediate the spinally generated caffeine-induced locomotion. In this study, we review the recently discovered properties of A2AR–D2R and A1R–D1R heteromers. Our studies demonstrate that these complexes are a necessary condition to sustain the canonical antagonistic interaction between a Gs-coupled receptor (A2AR or D1R) and a Gi-coupled receptor (D2R or A1R) at the adenylyl cyclase level, which constitutes a new concept in the field of G protein-coupled receptor physiology and pharmacology. A2AR antagonists targeting the striatal A2AR–D2R heteromer are already being considered as therapeutic agents in Parkinson's disease. In this study, we review the preclinical evidence that indicates that caffeine and A2AR antagonists could be used to treat the motivational symptoms of depression and attention-deficit/hyperactivity disorder, while A1R antagonists selectively targeting the spinal A1R–D1R heteromer could be used in the recovery of spinal cord injury.
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Affiliation(s)
- Sergi Ferré
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland
| | - Manuel Díaz-Ríos
- Department of Anatomy and Neurobiology, Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
| | - John D Salamone
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut
| | - Rui Daniel Prediger
- Department of Pharmacology, Federal University of Santa Catarina, Florianópolis, Brazil
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Rivera-Oliver M, Moreno E, Álvarez-Bagnarol Y, Ayala-Santiago C, Cruz-Reyes N, Molina-Castro GC, Clemens S, Canela EI, Ferré S, Casadó V, Díaz-Ríos M. Adenosine A 1-Dopamine D 1 Receptor Heteromers Control the Excitability of the Spinal Motoneuron. Mol Neurobiol 2018; 56:797-811. [PMID: 29797183 DOI: 10.1007/s12035-018-1120-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/11/2018] [Indexed: 10/16/2022]
Abstract
While the role of the ascending dopaminergic system in brain function and dysfunction has been a subject of extensive research, the role of the descending dopaminergic system in spinal cord function and dysfunction is just beginning to be understood. Adenosine plays a key role in the inhibitory control of the ascending dopaminergic system, largely dependent on functional complexes of specific subtypes of adenosine and dopamine receptors. Combining a selective destabilizing peptide strategy with a proximity ligation assay and patch-clamp electrophysiology in slices from male mouse lumbar spinal cord, the present study demonstrates the existence of adenosine A1-dopamine D1 receptor heteromers in the spinal motoneuron by which adenosine tonically inhibits D1 receptor-mediated signaling. A1-D1 receptor heteromers play a significant control of the motoneuron excitability, represent main targets for the excitatory effects of caffeine in the spinal cord and can constitute new targets for the pharmacological therapy after spinal cord injury, motor aging-associated disorders and restless legs syndrome.
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Affiliation(s)
- Marla Rivera-Oliver
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Estefanía Moreno
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED) and Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona, University of Barcelona, 08028, Barcelona, Spain
| | - Yocasta Álvarez-Bagnarol
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Christian Ayala-Santiago
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Nicole Cruz-Reyes
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Gian Carlo Molina-Castro
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Enric I Canela
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED) and Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona, University of Barcelona, 08028, Barcelona, Spain
| | - Sergi Ferré
- Integrative Neurobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Triad Technology Building, 333 Cassell Drive, Baltimore, MD, 21224, USA.
| | - Vicent Casadó
- Center for Biomedical Research in Neurodegenerative Diseases Network (CIBERNED) and Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona, University of Barcelona, 08028, Barcelona, Spain
| | - Manuel Díaz-Ríos
- Department of Anatomy and Neurobiology and Institute of Neurobiology, University of Puerto Rico, Medical Sciences, Rio Piedras and Cayey Campuses, San Juan, 00936, Puerto Rico
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Ohashi M, Hirano T, Watanabe K, Katsumi K, Ohashi N, Baba H, Endo N, Kohno T. Hydrogen peroxide modulates synaptic transmission in ventral horn neurons of the rat spinal cord. J Physiol 2016; 594:115-34. [PMID: 26510999 PMCID: PMC4704504 DOI: 10.1113/jp271449] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 10/16/2015] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Excessive production of reactive oxygen species (ROS) is implicated in many central nervous system disorders; however, the physiological role of ROS in spinal ventral horn (VH) neurons remains poorly understood. We investigated how pathological levels of H2O2, an abundant ROS, regulate synaptic transmission in VH neurons of rats using a whole-cell patch clamp approach. H2O2 increased the release of glutamate and GABA from presynaptic terminals. The increase in glutamate release involved N-type voltage-gated calcium channels (VGCCs), ryanodine receptors (RyRs), and inositol trisphosphate receptors (IP3 Rs); the increase in GABA release, which inhibited glutamatergic transmission, involved IP3 R. Inhibiting N-type VGCCs and RyRs attenuates excitotoxicity resulting from increased glutamatergic activity while preserving the neuroprotective effects of GABA, and may represent a novel strategy for treating H2O2-induced motor neuron disorders resulting from trauma or ischaemia-reperfusion injury. Excessive production of reactive oxygen species (ROS) is a critical component of the cellular and molecular pathophysiology of many central nervous system (CNS) disorders, including trauma, ischaemia-reperfusion injury, and neurodegenerative diseases. Hydrogen peroxide (H2O2), an abundant ROS, modulates synaptic transmission and contributes to neuronal damage in the CNS; however, the pathophysiological role of H2O2 in spinal cord ventral horn (VH) neurons remains poorly understood, despite reports that these neurons are highly vulnerable to oxidative stress and ischaemia. This was investigated in the present study using a whole-cell patch clamp approach in rats. We found that exogenous application of H2O2 increased the release of glutamate from excitatory presynaptic terminals and γ-aminobutyric acid (GABA) from inhibitory presynaptic terminals. The increase of glutamate release was induced in part by an increase in Ca(2+) influx through N-type voltage-gated calcium channels (VGCCs) as well as by ryanodine receptor (RyR)- and inositol trisphosphate receptor-mediated Ca(2+) release from the endoplasmic reticulum (ER). In inhibitory presynaptic neurons, increased IP3 R-mediated Ca(2+) release from the ER increased GABAergic transmission, which served to rescue VH neurons from excessive release of glutamate from presynaptic terminals. These findings indicate that inhibiting N-type VGCCs or RyRs may attenuate excitotoxicity resulting from increased glutamatergic activity while preserving the neuroprotective effects of GABA, and may therefore represent a novel and targeted strategy for preventing and treating H2O2-induced motor neuron disorders.
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Affiliation(s)
- Masayuki Ohashi
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Toru Hirano
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Kei Watanabe
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Keiichi Katsumi
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Nobuko Ohashi
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Hiroshi Baba
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Naoto Endo
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Tatsuro Kohno
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
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An adenosine kinase inhibitor, ABT-702, inhibits spinal nociceptive transmission by adenosine release via equilibrative nucleoside transporters in rat. Neuropharmacology 2015; 97:160-70. [DOI: 10.1016/j.neuropharm.2015.05.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 05/20/2015] [Accepted: 05/27/2015] [Indexed: 02/02/2023]
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Witts EC, Nascimento F, Miles GB. Adenosine-mediated modulation of ventral horn interneurons and spinal motoneurons in neonatal mice. J Neurophysiol 2015; 114:2305-15. [PMID: 26311185 PMCID: PMC4609759 DOI: 10.1152/jn.00574.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 08/21/2015] [Indexed: 01/20/2023] Open
Abstract
Neuromodulation allows neural networks to adapt to varying environmental and biomechanical demands. Purinergic signaling is known to be an important modulatory system in many parts of the CNS, including motor control circuitry. We have recently shown that adenosine modulates the output of mammalian spinal locomotor control circuitry (Witts EC, Panetta KM, Miles GB. J Neurophysiol 107: 1925–1934, 2012). Here we investigated the cellular mechanisms underlying this adenosine-mediated modulation. Whole cell patch-clamp recordings were performed on ventral horn interneurons and motoneurons within in vitro mouse spinal cord slice preparations. We found that adenosine hyperpolarized interneurons and reduced the frequency and amplitude of synaptic inputs to interneurons. Both effects were blocked by the A1-type adenosine receptor antagonist DPCPX. Analysis of miniature postsynaptic currents recorded from interneurons revealed that adenosine reduced their frequency but not amplitude, suggesting that adenosine acts on presynaptic receptors to modulate synaptic transmission. In contrast to interneurons, recordings from motoneurons revealed an adenosine-mediated depolarization. The frequency and amplitude of synaptic inputs to motoneurons were again reduced by adenosine, but we saw no effect on miniature postsynaptic currents. Again these effects on motoneurons were blocked by DPCPX. Taken together, these results demonstrate differential effects of adenosine, acting via A1 receptors, in the mouse spinal cord. Adenosine has a general inhibitory action on ventral horn interneurons while potentially maintaining motoneuron excitability. This may allow for adaptation of the locomotor pattern generated by interneuronal networks while helping to ensure the maintenance of overall motor output.
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Affiliation(s)
- Emily C Witts
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, United Kingdom
| | - Filipe Nascimento
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, United Kingdom
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, United Kingdom
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Yamanaka M, Taniguchi W, Nishio N, Hashizume H, Yamada H, Yoshida M, Nakatsuka T. In vivo patch-clamp analysis of the antinociceptive actions of TRPA1 activation in the spinal dorsal horn. Mol Pain 2015; 11:20. [PMID: 25896791 PMCID: PMC4422151 DOI: 10.1186/s12990-015-0021-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/10/2015] [Indexed: 01/24/2023] Open
Abstract
Background Transient receptor potential (TRP) channels are nonselective cation channels expressed in a variety of sensory structures, and are important molecular mediators of thermal, mechanical, cellular and chemical signals. We investigated the function of one key member of the TRP superfamily, TRPA1, in the spinal dorsal horn using in vivo patch-clamp recordings. Results The application of allyl isothiocyanate (AITC), a TRPA1 agonist, significantly increased the frequency and amplitude of inhibitory postsynaptic currents (IPSCs; holding potential (VH) = 0 mV) as well as excitatory postsynaptic currents (EPSCs; VH = −70 mV) in substantia gelatinosa (SG) neurons. The AITC-induced increases in EPSC frequency and amplitude were resistant to the Na+ channel blocker tetrodotoxin (TTX). In the presence of the glutamate receptor antagonists CNQX and AP5, AITC did not generate any synaptic activity. The AITC-induced increases in IPSC frequency and amplitude were abolished by TTX or glutamate receptor antagonists. Moreover, the duration of IPSCs enhanced by TRPA1 activation were significantly longer than those of EPSCs enhanced by activation of this channel in the spinal dorsal horn. AITC induced hyperpolarization of the membrane potential of SG neurons in the spinal cord but depolarized the membrane potential in the presence of TTX. Furthermore, we examined the effects of mechanical stimuli to the skin during TRPA1 activation in the spinal dorsal horn in normal rats in both voltage-clamp and current-clamp modes. In the peripheral tissue stimuli test, AITC significantly suppressed EPSCs evoked by pinch or air puff stimulation of the skin. In current-clamp mode, AITC significantly suppressed excitatory postsynaptic potentials (EPSPs) evoked by pinch stimuli. Conclusions TRPA1 appears to be localized not only at presynaptic terminals on SG neurons, enhancing glutamate release, but also in the terminals of primary afferents innervating spinal inhibitory interneurons, which have synaptic interactions with SG neurons. This study offers further insight into the mechanisms underlying the possible antinociceptive actions of TRPA1 activation in the spinal dorsal horn. Our findings suggest that pharmacological activation of spinal TRPA1 channels may have therapeutic potential for the treatment of pain.
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Affiliation(s)
- Manabu Yamanaka
- Department of Orthopaedic Surgery, Wakayama Medical University, Wakayama, 641-8509, Japan.
| | - Wataru Taniguchi
- Pain Research Center, Kansai University of Health Sciences, Kumatori, Osaka, 590-0482, Japan.
| | - Naoko Nishio
- Department of Orthopaedic Surgery, Wakayama Medical University, Wakayama, 641-8509, Japan. .,Pain Research Center, Kansai University of Health Sciences, Kumatori, Osaka, 590-0482, Japan.
| | - Hiroshi Hashizume
- Department of Orthopaedic Surgery, Wakayama Medical University, Wakayama, 641-8509, Japan.
| | - Hiroshi Yamada
- Department of Orthopaedic Surgery, Wakayama Medical University, Wakayama, 641-8509, Japan.
| | - Munehito Yoshida
- Department of Orthopaedic Surgery, Wakayama Medical University, Wakayama, 641-8509, Japan.
| | - Terumasa Nakatsuka
- Pain Research Center, Kansai University of Health Sciences, Kumatori, Osaka, 590-0482, Japan.
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Ng SK, Higashimori H, Tolman M, Yang Y. Suppression of adenosine 2a receptor (A2aR)-mediated adenosine signaling improves disease phenotypes in a mouse model of amyotrophic lateral sclerosis. Exp Neurol 2015; 267:115-22. [PMID: 25779930 DOI: 10.1016/j.expneurol.2015.03.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 02/27/2015] [Accepted: 03/05/2015] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressing neurodegenerative disease in which the majority of upper and lower motor neurons are degenerated. Despite intensive efforts to identify drug targets and develop neuroprotective strategies, effective therapeutics for ALS remains unavailable. The identification and characterization of novel targets and pathways remain crucial in the development of ALS therapeutics. Adenosine is a major neuromodulator that actively regulates synaptic transmission. Interestingly, adenosine levels are significantly elevated in the cerebrospinal fluid (CSF) of progressing human ALS patients. In the current study, we showed that adenosine 2a receptor (A2aR), but not adenosine 1 receptor (A1R), is highly enriched in spinal (motor) neurons. A2aR expression is also selectively increased at the symptomatic onset in the spinal cords of SOD1G93A mice and end-stage human ALS spinal cords. Interestingly, we found that direct adenosine treatment is sufficient to induce embryonic stem cell-derived motor neuron (ESMN) cell death in cultures. Subsequent pharmacological inhibition and partial genetic ablation of A2aR (A2aR(+/-)) significantly protect ESMN from SOD1G93A(+) astrocyte-induced cell death and delay disease progression of SOD1G93A mice. Taken together, our results provide compelling novel evidence that A2aR-mediated adenosine signaling contributes to the selective spinal motor neuron degeneration observed in the SOD1G93A mouse model of ALS.
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Affiliation(s)
- Seng Kah Ng
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA 02111, USA
| | - Haruki Higashimori
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA 02111, USA
| | - Michaela Tolman
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA 02111, USA; Neuroscience Program, Tufts Sackler School of Graduate Biomedical Sciences, 136 Harrison Ave, Boston, MA 02111, USA
| | - Yongjie Yang
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA 02111, USA; Neuroscience Program, Tufts Sackler School of Graduate Biomedical Sciences, 136 Harrison Ave, Boston, MA 02111, USA.
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The mu opioid receptor activation does not affect ischemia-induced agonal currents in rat spinal ventral horn. J Anesth 2014; 28:839-45. [DOI: 10.1007/s00540-014-1829-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 03/27/2014] [Indexed: 11/26/2022]
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González-Fernández E, Sánchez-Gómez MV, Pérez-Samartín A, Arellano RO, Matute C. A3 Adenosine receptors mediate oligodendrocyte death and ischemic damage to optic nerve. Glia 2013; 62:199-216. [PMID: 24311446 DOI: 10.1002/glia.22599] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 10/28/2013] [Accepted: 10/28/2013] [Indexed: 11/07/2022]
Abstract
Adenosine receptor activation is involved in myelination and in apoptotic pathways linked to neurodegenerative diseases. In this study, we investigated the effects of adenosine receptor activation in the viability of oligodendrocytes of the rat optic nerve. Selective activation of A3 receptors in pure cultures of oligodendrocytes caused concentration-dependent apoptotic and necrotic death which was preceded by oxidative stress and mitochondrial membrane depolarization. Oligodendrocyte apoptosis induced by A3 receptor activation was caspase-dependent and caspase-independent. In addition to dissociated cultures, incubation of optic nerves ex vivo with adenosine and the A3 receptor agonist 2-CI-IB-MECA(1-[2-Chloro-6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-b-D-ribofuranuronamide)-induced caspase-3 activation, oligodendrocyte damage, and myelin loss, effects which were prevented by the presence of caffeine and the A3 receptor antagonist MRS 1220 (N-[9-Chloro-2-(2-furanyl)[1,2,4]-triazolo [1,5-c]quinazolin-5-yl]benzene acetamide). Finally, ischemia-induced injury and functional loss to the optic nerve was attenuated by blocking A3 receptors. Together, these results indicate that adenosine may trigger oligodendrocyte death via activation of A3 receptors and suggest that this mechanism contributes to optic nerve and white matter ischemic damage.
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Affiliation(s)
- Estíbaliz González-Fernández
- CIBERNED, Achucarro Basque Center for Neuroscience and Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), E-48940, Leioa, Spain
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Paterniti I, Melani A, Cipriani S, Corti F, Mello T, Mazzon E, Esposito E, Bramanti P, Cuzzocrea S, Pedata F. Selective adenosine A2A receptor agonists and antagonists protect against spinal cord injury through peripheral and central effects. J Neuroinflammation 2011; 8:31. [PMID: 21486435 PMCID: PMC3096915 DOI: 10.1186/1742-2094-8-31] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 04/12/2011] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Permanent functional deficits following spinal cord injury (SCI) arise both from mechanical injury and from secondary tissue reactions involving inflammation. Enhanced release of adenosine and glutamate soon after SCI represents a component in the sequelae that may be responsible for resulting functional deficits. The role of adenosine A2A receptor in central ischemia/trauma is still to be elucidated. In our previous studies we have demonstrated that the adenosine A2A receptor-selective agonist CGS21680, systemically administered after SCI, protects from tissue damage, locomotor dysfunction and different inflammatory readouts. In this work we studied the effect of the adenosine A2A receptor antagonist SCH58261, systemically administered after SCI, on the same parameters. We investigated the hypothesis that the main action mechanism of agonists and antagonists is at peripheral or central sites. METHODS Spinal trauma was induced by extradural compression of SC exposed via a four-level T5-T8 laminectomy in mouse. Three drug-dosing protocols were utilized: a short-term systemic administration by intraperitoneal injection, a chronic administration via osmotic minipump, and direct injection into the spinal cord. RESULTS SCH58261, systemically administered (0.01 mg/kg intraperitoneal. 1, 6 and 10 hours after SCI), reduced demyelination and levels of TNF-α, Fas-L, PAR, Bax expression and activation of JNK mitogen-activated protein kinase (MAPK) 24 hours after SCI. Chronic SCH58261 administration, by mini-osmotic pump delivery for 10 days, improved the neurological deficit up to 10 days after SCI. Adenosine A2A receptors are physiologically expressed in the spinal cord by astrocytes, microglia and oligodendrocytes. Soon after SCI (24 hours), these receptors showed enhanced expression in neurons. Both the A2A agonist and antagonist, administered intraperitoneally, reduced expression of the A2A receptor, ruling out the possibility that the neuroprotective effects of the A2A agonist are due to A2A receptor desensitization. When the A2A antagonist and agonist were centrally injected into injured SC, only SCH58261 appeared neuroprotective, while CGS21680 was ineffective. CONCLUSIONS Our results indicate that the A2A antagonist protects against SCI by acting on centrally located A2A receptors. It is likely that blockade of A2A receptors reduces excitotoxicity. In contrast, neuroprotection afforded by the A2A agonist may be primarily due to peripheral effects.
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Laubach VE, French BA, Okusa MD. Targeting of adenosine receptors in ischemia-reperfusion injury. Expert Opin Ther Targets 2010; 15:103-18. [PMID: 21110787 DOI: 10.1517/14728222.2011.541441] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
IMPORTANCE OF THE FIELD Ischemia-reperfusion (IR) injury is a common problem after transplantation as well as myocardial infarction and stroke. IR initiates an inflammatory response leading to rapid tissue damage. Adenosine, produced in response to IR, is generally considered a protective signaling molecule and elicits its physiological responses through four distinct adenosine receptors. The short half-life, lack of specificity and rapid metabolism limits the use of adenosine as a therapeutic agent. Thus, intense research efforts have focused on the synthesis and implementation of specific adenosine receptor agonists and antagonists as potential therapeutic agents for a variety of inflammatory conditions including IR injury. AREAS COVERED IN THIS REVIEW Current knowledge on IR injury with a focus on lung, heart and kidney and studies that have advanced our understanding of the role of adenosine receptors and the therapeutic potential of adenosine receptor agonists and antagonists for the prevention of IR injury. WHAT THE READER WILL GAIN Insight into the role of adenosine receptor signaling in IR injury. TAKE HOME MESSAGE No therapies are currently available that specifically target IR injury; however, targeting of specific adenosine receptors may offer therapeutic strategies in this regard.
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Affiliation(s)
- Victor E Laubach
- University of Virginia Health System, Charlottesville, 22908, USA.
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Wang J, Zhang P, Li JY, Chen LQ, Huang CZ, Li YF. Adenosine-aptamer recognition-induced assembly of gold nanorods and a highly sensitive plasmon resonance coupling assay of adenosine in the brain of model SD rat. Analyst 2010; 135:2826-31. [PMID: 20830327 DOI: 10.1039/c0an00365d] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this contribution, we report a molecular recognition between adenosine and its aptamer, which leads to the formation of a four-stranded tetraplex structures (G-quartet) of the aptamer. It is found that the formed G-quartet could induce the side-by-side self-assembly of gold nanorods (AuNRs) owing to the electrostatic interaction between the positive charge of cetyltrimethylammonium bromide (CTAB) on the AuNR surface and the negative charge of the formed G-quartet. Furthermore, the side-by-side self-assembly of AuNRs is characterized by the enhancement of plasmon resonance light scattering (PRLS) signals and the blue-shift of the longitudinal plasmon resonance absorption (LPRA) band owing to the plasmon resonance coupling. Then, based on the enhanced PRLS signals, a simple, highly selective and sensitive detection method for adenosine was developed in the range of 4.0-80.0 nM with the limit of determination of 2.0 nM, which is up to now the best sensitive optical detection method to our knowledge. This method has been successfully applied to the detection of adenosine phosphates in the brains of SD rats, which was in good agreement with a high-performance liquid chromatographic (HPLC) method.
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Affiliation(s)
- Jian Wang
- Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
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