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Le Merrer J, Detraux B, Gandía J, De Groote A, Fonteneau M, de Kerchove d'Exaerde A, Becker JAJ. Balance Between Projecting Neuronal Populations of the Nucleus Accumbens Controls Social Behavior in Mice. Biol Psychiatry 2024; 95:123-135. [PMID: 37207936 DOI: 10.1016/j.biopsych.2023.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 04/06/2023] [Accepted: 05/02/2023] [Indexed: 05/21/2023]
Abstract
BACKGROUND Deficient social interactions are a hallmark of major neuropsychiatric disorders, and accumulating evidence points to altered social reward and motivation as key underlying mechanisms of these pathologies. In the present study, we further explored the role of the balance of activity between D1 and D2 receptor-expressing striatal projection neurons (D1R- and D2R-SPNs) in the control of social behavior, challenging the hypothesis that excessive D2R-SPN activity, rather than deficient D1R-SPN activity, compromises social behavior. METHODS We selectively ablated D1R- and D2R-SPNs using an inducible diphtheria toxin receptor-mediated cell targeting strategy and assessed social behavior as well as repetitive/perseverative behavior, motor function, and anxiety levels. We tested the effects of optogenetic stimulation of D2R-SPNs in the nucleus accumbens (NAc) and pharmacological compounds repressing D2R-SPN. RESULTS Targeted deletion of D1R-SPNs in the NAc blunted social behavior in mice, facilitated motor skill learning, and increased anxiety levels. These behaviors were normalized by pharmacological inhibition of D2R-SPN, which also repressed transcription in the efferent nucleus, the ventral pallidum. Ablation of D1R-SPNs in the dorsal striatum had no impact on social behavior but impaired motor skill learning and decreased anxiety levels. Deletion of D2R-SPNs in the NAc produced motor stereotypies but facilitated social behavior and impaired motor skill learning. We mimicked excessive D2R-SPN activity by optically stimulating D2R-SPNs in the NAc and observed a severe deficit in social interaction that was prevented by D2R-SPN pharmacological inhibition. CONCLUSIONS Repressing D2R-SPN activity may represent a promising therapeutic strategy to relieve social deficits in neuropsychiatric disorders.
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Affiliation(s)
- Julie Le Merrer
- Physiologie de la Reproduction et des Comportements, Unité Mixte de Recherche Centre National de la Recherche Scientifique 7247, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement 0085, Institut National de la Santé et de la Recherche Médicale, Université de Tours, Nouzilly, France; iBrain, Unité Mixte de Recherche 1253 Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Faculté des Sciences et Techniques, Université de Tours, Tours, France.
| | - Bérangère Detraux
- Neurophy Lab, ULB Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium
| | - Jorge Gandía
- Physiologie de la Reproduction et des Comportements, Unité Mixte de Recherche Centre National de la Recherche Scientifique 7247, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement 0085, Institut National de la Santé et de la Recherche Médicale, Université de Tours, Nouzilly, France
| | - Aurélie De Groote
- Neurophy Lab, ULB Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium
| | - Mathieu Fonteneau
- iBrain, Unité Mixte de Recherche 1253 Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Faculté des Sciences et Techniques, Université de Tours, Tours, France
| | - Alban de Kerchove d'Exaerde
- Neurophy Lab, ULB Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium; WELBIO, Wavre, Belgium.
| | - Jérôme A J Becker
- Physiologie de la Reproduction et des Comportements, Unité Mixte de Recherche Centre National de la Recherche Scientifique 7247, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement 0085, Institut National de la Santé et de la Recherche Médicale, Université de Tours, Nouzilly, France; iBrain, Unité Mixte de Recherche 1253 Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Faculté des Sciences et Techniques, Université de Tours, Tours, France
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Kosmowska B, Ossowska K, Wardas J. Blockade of adenosine A 2A receptors inhibits Tremulous Jaw Movements as well as expression of zif-268 and GAD65 mRNAs in brain motor structures. Behav Brain Res 2022; 417:113585. [PMID: 34536428 DOI: 10.1016/j.bbr.2021.113585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/10/2021] [Accepted: 09/10/2021] [Indexed: 11/26/2022]
Abstract
Tremor is one of the motor symptoms of Parkinson's disease (PD), present also in neuroleptic-induced parkinsonism. Tremulous Jaw Movements (TJMs) are suggested to be a well-validated rodent model of PD resting tremor. TJMs can be induced by typical antipsychotics and are known to be reduced by different drugs, including adenosine A2A receptor antagonists. The aim of the present study was to search for brain structures involved in the tremorolytic action of SCH58261, a selective A2A receptor antagonist, in TJMs induced by subchronic pimozide. Besides TJMs, we evaluated in the same animals the expression of zif-268 mRNA (neuronal responsiveness marker), and mRNA levels for glutamic acid decarboxylase 65-kDa isoform (GAD65) and vesicular glutamate transporters 1 and 2 (vGluT1/2) in selected brain structures, as markers of GABAergic and glutamatergic neurons, respectively. We found that SCH58261 reduced the pimozide-induced TJMs. Pimozide increased the zif-268 mRNA level in the striatum, nucleus accumbens (NAc) core, and substantia nigra pars reticulata (SNr). Additionally, it increased GAD65 mRNA in the striatum and SNr, and vGluT2 mRNA levels in the subthalamic nucleus (STN). A positive correlation between zif-268, GAD65 and vGluT2 mRNAs and TJMs was found. SCH58261 reversed the pimozide-increased zif-268 mRNA in the striatum and NAc core and GAD65 mRNA in the striatum and SNr. In contrast, SCH58261 did not influence vGluT2 mRNA in STN. The present study suggests an importance of the striato-subthalamo-nigro-thalamic circuit in neuroleptic-induced TJMs. The tremorolytic effect of A2A receptor blockade seems to involve this circuit bypassing, however, STN.
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Affiliation(s)
- Barbara Kosmowska
- Department of Neuropsychopharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland.
| | - Krystyna Ossowska
- Department of Neuropsychopharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland.
| | - Jadwiga Wardas
- Department of Neuropsychopharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland.
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Jenner P, Mori A, Aradi SD, Hauser RA. Istradefylline - a first generation adenosine A 2A antagonist for the treatment of Parkinson's disease. Expert Rev Neurother 2021; 21:317-333. [PMID: 33507105 DOI: 10.1080/14737175.2021.1880896] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction It is now accepted that Parkinson's disease (PD) is not simply due to dopaminergic dysfunction, and there is interest in developing non-dopaminergic approaches to disease management. Adenosine A2A receptor antagonists represent a new way forward in the symptomatic treatment of PD.Areas covered In this narrative review, we summarize the literature supporting the utility of adenosine A2A antagonists in PD with a specific focus on istradefylline, the most studied and only adenosine A2A antagonist currently in clinical use.Expert opinion: At this time, the use of istradefylline in the treatment of PD is limited to the management of motor fluctuations as supported by the results of randomized clinical trials and evaluation by Japanese and USA regulatory authorities. The relatively complicated clinical development of istradefylline was based on classically designed studies conducted in PD patients with motor fluctuations on an optimized regimen of levodopa plus adjunctive dopaminergic medications. In animal models, there is consensus that a more robust effect of istradefylline in improving motor function is produced when combined with low or threshold doses of levodopa rather than with high doses that produce maximal dopaminergic improvement. Exploration of istradefylline as a 'levodopa sparing' strategy in earlier PD would seem warranted.
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Affiliation(s)
- Peter Jenner
- Institute of Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Akihisa Mori
- Medical Affairs Department, Kyowa Kirin Co Ltd, Otemachi, Chiyoda-ku, Tokyo, Japan
| | - Stephen D Aradi
- Department of Neurology, University of South Florida, Tampa, Florida, USA
| | - Robert A Hauser
- Department of Neurology, University of South Florida, Tampa, Florida, USA
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Pinna A, Serra M, Marongiu J, Morelli M. Pharmacological interactions between adenosine A 2A receptor antagonists and different neurotransmitter systems. Parkinsonism Relat Disord 2020; 80 Suppl 1:S37-S44. [PMID: 33349579 DOI: 10.1016/j.parkreldis.2020.10.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/23/2020] [Accepted: 10/11/2020] [Indexed: 12/21/2022]
Abstract
While Parkinson's disease (PD) is traditionally characterized by dopaminergic neuron degeneration, several neurotransmitters and neuromodulators besides dopamine are also involved in the onset and progression of the disease and its symptoms. The other principal neurotransmitters/neuromodulators known to control basal ganglia functions and, in particular, motor functions, are GABA, glutamate, serotonin (5-HT), noradrenaline, acetylcholine, adenosine and endocannabinoids. Among these, adenosine is the most relevant, acting through its adenosine A2A receptor. Work in experimental models of PD has established the effects of A2A receptor antagonists, including the alleviation of disrupted dopamine functions and improved efficacy of dopamine replacement therapy. Moreover, positive interactions between A2A receptor antagonists and both D2 and D1 receptor agonists have been described in vitro at the receptor-receptor level or in more complex in vivo models of PD, respectively. In addition, the interactions between A2A receptor antagonists and glutamate ionotropic GluN2B-containing N-Methyl-d-aspartic acid receptors, or metabotropic glutamate (mGlu) receptors, including both mGlu5 receptor inhibitors and mGlu4 receptor activators, have been reported in both in vitro and in vivo animal models of PD, as have positive interactions between A2A and endocannabinoid CB1 receptor antagonists. At the same time, a combination of A2A receptor antagonists and 5-HT1A-5-HT1B receptor agonists have been described to modulate the expression of dyskinesia induced by chronic dopamine replacement therapy.
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Affiliation(s)
- Annalisa Pinna
- National Research Council of Italy, Neuroscience Institute - Cagliari, Cagliari, Italy.
| | - Marcello Serra
- Department of Biomedical Sciences, Section of Neuroscience, University of Cagliari, Cagliari, Italy
| | - Jacopo Marongiu
- Department of Biomedical Sciences, Section of Neuroscience, University of Cagliari, Cagliari, Italy
| | - Micaela Morelli
- National Research Council of Italy, Neuroscience Institute - Cagliari, Cagliari, Italy; Department of Biomedical Sciences, Section of Neuroscience, University of Cagliari, Cagliari, Italy.
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LeWitt PA, Aradi SD, Hauser RA, Rascol O. The challenge of developing adenosine A 2A antagonists for Parkinson disease: Istradefylline, preladenant, and tozadenant. Parkinsonism Relat Disord 2020; 80 Suppl 1:S54-S63. [PMID: 33349581 DOI: 10.1016/j.parkreldis.2020.10.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/07/2020] [Accepted: 10/12/2020] [Indexed: 11/28/2022]
Abstract
Laboratory and clinical experience have pointed to the value of targeting motor pathways emerging from the striatum to treat problems arising in advanced Parkinson's disease (PD). These pathways are selectively populated with a subtype of adenosine binding sites (A2A receptors) that offer a target for improving PD symptomatology. Several compounds were developed that possess high selectivity and potency for blocking this receptor. Three of these compounds - istradefylline, preladenant, and tozadenant - were chosen for clinical development programs that culminated in Phase 3 multicenter randomized clinical trials. Each of these drugs exert virtually no off-target neurochemical effects. Clinical trials with these drugs focused upon reducing OFF time when administered adjunctly to levodopa and other antiparkinsonian medications. Despite promising Phase 2 data, preladenant did not show efficacy when tested in a randomized placebo-controlled Phase 3 clinical trial. Reports of hematological toxicity necessitated ceasing an ongoing Phase 3 investigation of tozadenant. Following a challenging approval process, based on the results of randomized clinical trials carried out in the U.S. and Japan, istradefylline received approval in these countries for treatment of OFF episodes.
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Affiliation(s)
- Peter A LeWitt
- Department of Neurology, Wayne State University School of Medicine, USA; Department of Neurology, Henry Ford Hospital, Detroit, MI, USA.
| | - Stephen D Aradi
- Department of Neurology, University of South Florida, Tampa, FL, USA
| | - Robert A Hauser
- Department of Neurology, University of South Florida, Tampa, FL, USA
| | - Olivier Rascol
- Clinical Investigation Center CIC1436, Department of Pharmacology and Neurosciences, Toulouse Parkinson Expert Center, NS-Park/FCRIN Network and NeuroToul COEN Center, University Hospital of Toulouse, INSERM and University of Toulouse 3, Toulouse, France
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6
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Mori A. How do adenosine A 2A receptors regulate motor function? Parkinsonism Relat Disord 2020; 80 Suppl 1:S13-S20. [PMID: 33349575 DOI: 10.1016/j.parkreldis.2020.09.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 01/17/2023]
Abstract
Adenosine A2A receptor antagonism is a new therapeutic strategy in the symptomatic treatment of Parkinson's disease (PD). This review addresses how adenosine A2A receptors are involved with the control of motor function via the basal ganglia-thalamocortical circuit, and considers the anatomical localization and physiological function of the receptor, along with its ultrastructural localization in critical areas/neurons of the circuit. Based on this understanding of the functional significance of the adenosine A2A receptor in the basal ganglia, the mode of action of A2A receptor antagonists is explored in terms of the dynamic functioning of the basal ganglia and the activity of the internal circuits of the striatum in PD. Finally, the pathophysiological differences between the normal and PD states are examined to emphasize the importance of the adenosine A2A receptor.
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Abstract
Levodopa is the most effective medication for the treatment of the motor symptoms of Parkinson's disease. However, over time, the clinical response to levodopa becomes complicated by a reduction in the duration and reliability of motor improvement (motor fluctuations) and the emergence of involuntary movements (levodopa-induced dyskinesia). Strategies that have been attempted in an effort to delay the development of these motor complications include levodopa sparing and continuous dopaminergic therapy. Once motor complications occur, a wide array of medical treatments is available to maximize motor function through the day while limiting dyskinesia. Here, we review the clinical features, epidemiology, and risk factors for the development of motor complications, as well as strategies for their prevention and medical management.
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Affiliation(s)
- Stephen D Aradi
- Department of Neurology, Parkinson's Foundation Center of Excellence, University of South Florida, Tampa, FL, USA.
| | - Robert A Hauser
- Department of Neurology, Parkinson's Foundation Center of Excellence, University of South Florida, Tampa, FL, USA
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8
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Role of adenosine A 2A receptors in motor control: relevance to Parkinson's disease and dyskinesia. J Neural Transm (Vienna) 2018; 125:1273-1286. [PMID: 29396609 DOI: 10.1007/s00702-018-1848-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/26/2018] [Indexed: 12/16/2022]
Abstract
Adenosine is an endogenous purine nucleoside that regulates several physiological functions, at the central and peripheral levels. Besides, adenosine has emerged as a major player in the regulation of motor behavior. In fact, adenosine receptors of the A2A subtype are highly enriched in the caudate-putamen, which is richly innervated by dopamine. Moreover, several studies in experimental animals have consistently demonstrated that the pharmacological antagonism of A2A receptors has a facilitatory influence on motor behavior. Taken together, these findings have envisaged A2A receptors as a promising target for symptomatic therapies aimed at ameliorating motor deficits. Accordingly, A2A receptor antagonists have been extensively studied as new agents for the treatment of Parkinson's disease (PD), the epitome of motor disorders. In this review, we provide an overview of the effects that adenosine A2A receptor antagonists elicit in rodent and primate experimental models of PD, with regard to the counteraction of motor deficits as well as to manifestation of dyskinesia and motor fluctuations. Moreover, we briefly present the results of clinical trials of A2A receptor antagonists in PD patients experiencing motor fluctuations, with particular regard to dyskinesia. Finally, we discuss the interaction between A2A receptor antagonists and serotonin receptor agonists, since combined administration of these drugs has recently emerged as a new potential therapeutic strategy in the treatment of dyskinesia.
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9
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Isoaho N, Peltola E, Sainio S, Koskinen J, Laurila T. Pt-grown carbon nanofibers for enzymatic glutamate biosensors and assessment of their biocompatibility. RSC Adv 2018; 8:35802-35812. [PMID: 35547905 PMCID: PMC9088215 DOI: 10.1039/c8ra07766e] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/09/2018] [Indexed: 01/11/2023] Open
Abstract
Application-specific carbon nanofibers grown from Pt-catalyst layers have been shown to be a promising material for biosensor development. Here we demonstrate immobilization of glutamate oxidase on them and their use for amperometric detection of glutamate at two different potentials. At −0.15 V vs. Ag/AgCl at concentrations higher than 100 μM the oxygen reduction reaction severely interferes with the enzymatic production of H2O2 and consequently affects the detection of glutamate. On the other hand, at 0.6 V vs. Ag/AgCl enzyme saturation starts to affect the measurement above a glutamate concentration of 100 μM. Moreover, we suggest here that glutamate itself might foul Pt surfaces to some degree, which should be taken into account when designing Pt-based sensors operating at high anodic potentials. Finally, the Pt-grown and Ni-grown carbon nanofibers were shown to be biocompatible. However, the cells on Pt-grown carbon nanofibers had different morphology and formation of filopodia compared to those on Ni-grown carbon nanofibers. The effect was expected to be caused rather by the different fiber dimensions between the samples than the catalyst metal itself. Further experiments are required to find the optimal dimensions of CNFs for biological purposes. Pt-grown carbon nanofibers were utilized for the fabrication of glutamate biosensors and in addition their biocompatibility was assessed.![]()
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Affiliation(s)
- Noora Isoaho
- Department of Electrical Engineering and Automation
- School of Electrical Engineering
- Aalto University
- 00076 Aalto
- Finland
| | - Emilia Peltola
- Department of Electrical Engineering and Automation
- School of Electrical Engineering
- Aalto University
- 00076 Aalto
- Finland
| | - Sami Sainio
- Department Chemistry and Materials Science
- School of Chemical Technology
- Aalto University
- 00076 Aalto
- Finland
| | - Jari Koskinen
- Department Chemistry and Materials Science
- School of Chemical Technology
- Aalto University
- 00076 Aalto
- Finland
| | - Tomi Laurila
- Department of Electrical Engineering and Automation
- School of Electrical Engineering
- Aalto University
- 00076 Aalto
- Finland
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Nguyen MD, Wang Y, Ganesana M, Venton BJ. Transient Adenosine Release Is Modulated by NMDA and GABA B Receptors. ACS Chem Neurosci 2017; 8:376-385. [PMID: 28071892 DOI: 10.1021/acschemneuro.6b00318] [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] [Indexed: 01/08/2023] Open
Abstract
Adenosine is a neuroprotective agent that modulates neurotransmission and is modulated by other neurotransmitters. Spontaneous, transient adenosine is a recently discovered mode of signaling where adenosine is released and cleared from the extracellular space quickly, in less than three seconds. Spontaneous adenosine release is regulated by adenosine A1 and A2a receptors, but regulation by other neurotransmitter receptors has not been studied. Here, we examined the effect of glutamate and GABA receptors on the concentration and frequency of spontaneous, transient adenosine release by measuring adenosine with fast-scan cyclic voltammetry in the rat caudate-putamen. The glutamate NMDA antagonist, 3-(R-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP, 6.25 mg/kg i.p.), increased the frequency of adenosine transients and the concentration of individual transients, but NMDA (agonist, 50 mg/kg, i.p.) did not change the frequency. In contrast, antagonists of other glutamate receptors had no effect on the frequency or concentration of transient adenosine release, including the AMPA antagonist NBQX (15 mg/kg i.p.) and the mGlu2/3 glutamate receptor antagonist LY 341495 (5 mg/kg i.p.). The GABAB antagonist CGP 52432 (30 mg/kg i.p.) significantly decreased the number of adenosine release events while the GABAB agonist baclofen (4 mg/kg i.p.) increased the frequency of adenosine release. The GABAA antagonist bicuculline (5 mg/kg i.p.) had no significant effects on adenosine. NMDA and GABAB likely act presynaptically, affecting the overall cell excitability for vesicular release. The ability to regulate adenosine with NMDA and GABAB receptors will help control the modulatory effects of transient adenosine release.
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Affiliation(s)
- Michael D. Nguyen
- Department
of Chemistry and
Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Ying Wang
- Department
of Chemistry and
Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Mallikarjunarao Ganesana
- Department
of Chemistry and
Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia 22904, United States
| | - B. Jill Venton
- Department
of Chemistry and
Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia 22904, United States
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Ko WKD, Camus SM, Li Q, Yang J, McGuire S, Pioli EY, Bezard E. An evaluation of istradefylline treatment on Parkinsonian motor and cognitive deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated macaque models. Neuropharmacology 2016; 110:48-58. [PMID: 27424102 DOI: 10.1016/j.neuropharm.2016.07.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 01/27/2023]
Abstract
Istradefylline (KW-6002), an adenosine A2A receptor antagonist, is used adjunct with optimal doses of L-3,4-dihydroxyphenylalanine (l-DOPA) to extend on-time in Parkinson's disease (PD) patients experiencing motor fluctuations. Clinical application of istradefylline for the management of other l-DOPA-induced complications, both motor and non-motor related (i.e. dyskinesia and cognitive impairments), remains to be determined. In this study, acute effects of istradefylline (60-100 mg/kg) alone, or with optimal and sub-optimal doses of l-DOPA, were evaluated in two monkey models of PD (i) the gold-standard 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated macaque model of parkinsonian and dyskinetic motor symptoms and (ii) the chronic low dose (CLD) MPTP-treated macaque model of cognitive (working memory and attentional) deficits. Behavioural analyses in l-DOPA-primed MPTP-treated macaques showed that istradefylline alone specifically alleviated postural deficits. When combined with an optimal l-DOPA treatment dose, istradefylline increased on-time, enhanced therapeutic effects on bradykinesia and locomotion, but exacerbated dyskinesia. Istradefylline treatment at specific doses with sub-optimal l-DOPA specifically alleviated bradykinesia. Cognitive assessments in CLD MPTP-treated macaques showed that the attentional and working memory deficits caused by l-DOPA were lowered after istradefylline administration. Taken together, these data support a broader clinical use of istradefylline as an adjunct treatment in PD, where specific treatment combinations can be utilised to manage various l-DOPA-induced complications, which importantly, maintain a desired anti-parkinsonian response.
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Affiliation(s)
- Wai Kin D Ko
- Motac Neuroscience Ltd, Manchester, United Kingdom.
| | | | - Qin Li
- Motac Neuroscience Ltd, Manchester, United Kingdom
| | | | | | - Elsa Y Pioli
- Motac Neuroscience Ltd, Manchester, United Kingdom
| | - Erwan Bezard
- Motac Neuroscience Ltd, Manchester, United Kingdom; Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France
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12
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De Deurwaerdère P, Di Giovanni G, Millan MJ. Expanding the repertoire of L-DOPA's actions: A comprehensive review of its functional neurochemistry. Prog Neurobiol 2016; 151:57-100. [PMID: 27389773 DOI: 10.1016/j.pneurobio.2016.07.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/18/2016] [Accepted: 07/03/2016] [Indexed: 01/11/2023]
Abstract
Though a multi-facetted disorder, Parkinson's disease is prototypically characterized by neurodegeneration of nigrostriatal dopaminergic neurons of the substantia nigra pars compacta, leading to a severe disruption of motor function. Accordingly, L-DOPA, the metabolic precursor of dopamine (DA), is well-established as a treatment for the motor deficits of Parkinson's disease despite long-term complications such as dyskinesia and psychiatric side-effects. Paradoxically, however, despite the traditional assumption that L-DOPA is transformed in residual striatal dopaminergic neurons into DA, the mechanism of action of L-DOPA is neither simple nor entirely clear. Herein, focussing on its influence upon extracellular DA and other neuromodulators in intact animals and experimental models of Parkinson's disease, we highlight effects other than striatal generation of DA in the functional profile of L-DOPA. While not excluding a minor role for glial cells, L-DOPA is principally transformed into DA in neurons yet, interestingly, with a more important role for serotonergic than dopaminergic projections. Moreover, in addition to the striatum, L-DOPA evokes marked increases in extracellular DA in frontal cortex, nucleus accumbens, the subthalamic nucleus and additional extra-striatal regions. In considering its functional profile, it is also important to bear in mind the marked (probably indirect) influence of L-DOPA upon cholinergic, GABAergic and glutamatergic neurons in the basal ganglia and/or cortex, while anomalous serotonergic transmission is incriminated in the emergence of L-DOPA elicited dyskinesia and psychosis. Finally, L-DOPA may exert intrinsic receptor-mediated actions independently of DA neurotransmission and can be processed into bioactive metabolites. In conclusion, L-DOPA exerts a surprisingly complex pattern of neurochemical effects of much greater scope that mere striatal transformation into DA in spared dopaminergic neurons. Their further experimental and clinical clarification should help improve both L-DOPA-based and novel strategies for controlling the motor and other symptoms of Parkinson's disease.
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Affiliation(s)
- Philippe De Deurwaerdère
- CNRS (Centre National de la Recherche Scientifique), Institut des Maladies Neurodégénératives, UMR CNRS 5293, F-33000 Bordeaux, France.
| | - Giuseppe Di Giovanni
- Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, UK; Department of Physiology & Biochemistry, Faculty of Medicine and Surgery, University of Malta, Malta
| | - Mark J Millan
- Institut de Recherche Servier, Pole for Therapeutic Innovation in Neuropsychiatry, 78290 Croissy/Seine,Paris, France
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Vorovenci RJ, Antonini A. The efficacy of oral adenosine A2Aantagonist istradefylline for the treatment of moderate to severe Parkinson’s disease. Expert Rev Neurother 2015; 15:1383-90. [DOI: 10.1586/14737175.2015.1113131] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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Rieck M, Schumacher-Schuh AF, Callegari-Jacques SM, Altmann V, Schneider Medeiros M, Rieder CR, Hutz MH. Is there a role for ADORA2A polymorphisms in levodopa-induced dyskinesia in Parkinson's disease patients? Pharmacogenomics 2015; 16:573-82. [PMID: 25872644 DOI: 10.2217/pgs.15.23] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
AIM Levodopa is first line treatment of Parkinson's disease (PD). However, its use is associated with the presence of motor fluctuations and dyskinesias. In recent years, adenosine A2A receptor (A2AR) is rising as a therapeutic target for PD. The aim of the present study was to investigate whether ADORA2A is associated with levodopa adverse effects. PATIENTS & METHODS Two hundred and eight PD patients on levodopa therapy were investigated. rs2298383 and rs3761422 at the ADORA2A gene were genotyped by allelic discrimination assays. RESULTS A trend for association was observed for both polymorphism and diplotypes with dyskinesia. CONCLUSION The present results should be considered as positive preliminary evidence. Further studies are needed to determine the association between ADORA2A and dyskinesia. Original submitted 3 December 2014; Revision submitted 13 February 2015.
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Affiliation(s)
- Mariana Rieck
- Departmento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Caixa postal 15053, Porto Alegre, RS, 91501-970, Brazil
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15
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Sonsalla PK, Coleman C, Wong LY, Harris SL, Richardson JR, Gadad BS, Li W, German DC. The angiotensin converting enzyme inhibitor captopril protects nigrostriatal dopamine neurons in animal models of parkinsonism. Exp Neurol 2013; 250:376-83. [PMID: 24184050 PMCID: PMC3889207 DOI: 10.1016/j.expneurol.2013.10.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 10/11/2013] [Accepted: 10/23/2013] [Indexed: 11/21/2022]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by a prominent loss of nigrostriatal dopamine (DA) neurons with an accompanying neuroinflammation. The peptide angiotensin II (AngII) plays a role in oxidative-stress induced disorders and is thought to mediate its detrimental actions via activation of AngII AT1 receptors. The brain renin-angiotensin system is implicated in neurodegenerative disorders including PD. Blockade of the angiotensin converting enzyme or AT1 receptors provides protection in acute animal models of parkinsonism. We demonstrate here that treatment of mice with the angiotensin converting enzyme inhibitor captopril protects the striatum from acutely administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrine (MPTP), and that chronic captopril protects the nigral DA cell bodies from degeneration in a progressive rat model of parkinsonism created by the chronic intracerebral infusion of 1-methyl-4-phenylpyridinium (MPP+). The accompanying activation of microglia in the substantia nigra of MPP+-treated rats was reduced by the chronic captopril treatment. These findings indicate that captopril is neuroprotective for nigrostriatal DA neurons in both acute and chronic rodent PD models. Targeting the brain AngII pathway may be a feasible approach to slowing neurodegeneration in PD.
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Affiliation(s)
- Patricia K Sonsalla
- Department of Neurology, Rutgers, The State University of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ, USA.
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16
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Jones N, Bleickardt C, Mullins D, Parker E, Hodgson R. A2A receptor antagonists do not induce dyskinesias in drug-naive or L-dopa sensitized rats. Brain Res Bull 2013; 98:163-9. [PMID: 23838432 DOI: 10.1016/j.brainresbull.2013.07.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/28/2013] [Accepted: 07/01/2013] [Indexed: 12/26/2022]
Abstract
L-dopa, the precursor to dopamine, is currently the gold standard treatment for Parkinson's disease (PD). However, chronic exposure is associated with L-dopa-induced dyskinesias (LIDs), a serious side effect characterized by involuntary movements. Adenosine A2A receptor antagonists have been studied as a novel non-dopaminergic PD treatment. Because A2A receptor antagonists do not act on dopamine receptors, it has been hypothesized that they will not induce dyskinesias characteristic of L-dopa. To test this hypothesis in a rodent model, the A2A receptor antagonists SCH 412348 (3 mg/kg), vipadenant (10 mg/kg), caffeine (30 mg/kg), or istradefylline (3 mg/kg) were chronically (19-22 days) administered to Sprague Dawley rats, and dyskinetic behaviors were scored across this chronic dosing paradigm. Unlike L-dopa, there was no evidence of dyskinetic activity resulting from any of the four A2A receptor antagonists tested. When delivered to animals previously sensitized with L-dopa (6 mg/kg), SCH 412348, vipadenant, caffeine or istradefylline treatment produced no dyskinesias. When administered in combination with L-dopa (6 mg/kg), SCH 412348 (3 mg/kg) neither exacerbated nor prevented the induction of LIDs over the course of 19 days of treatment. Collectively, our data indicate that A2A receptor antagonists are likely to have a reduced dyskinetic liability relative to L-dopa but do not block dyskinesias when coadministered with L-dopa. Clinical studies are required to fully understand the dyskinesia profiles of A2A receptor antagonists.
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Affiliation(s)
- N Jones
- Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
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17
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18
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Fliegel S, Brand I, Spanagel R, Noori HR. Ethanol-induced alterations of amino acids measured by in vivo microdialysis in rats: a meta-analysis. In Silico Pharmacol 2013; 1:7. [PMID: 25505652 PMCID: PMC4230485 DOI: 10.1186/2193-9616-1-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 05/07/2013] [Indexed: 12/14/2022] Open
Abstract
PURPOSE In recent years in vivo microdialysis has become an important method in research studies investigating the alterations of neurotransmitters in the extracellular fluid of the brain. Based on the major involvement of glutamate and γ-aminobutyric acid (GABA) in mediating a variety of alcohol effects in the mammalian brain, numerous microdialysis studies have focused on the dynamical behavior of these systems in response to alcohol. METHODS Here we performed multiple meta-analyses on published datasets from the rat brain: (i) we studied basal extracellular concentrations of glutamate and GABA in brain regions that belong to a neurocircuitry involved in neuropsychiatric diseases, especially in alcoholism (Noori et al., Addict Biol 17:827-864, 2012); (ii) we examined the effect of acute ethanol administration on glutamate and GABA levels within this network and (iii) we studied alcohol withdrawal-induced alterations in glutamate and GABA levels within this neurocircuitry. RESULTS For extraction of basal concentrations of these neurotransmitters, datasets of 6932 rats were analyzed and the absolute basal glutamate and GABA levels were estimated for 18 different brain sites. In response to different doses of acute ethanol administration, datasets of 529 rats were analyzed and a non-linear dose response (glutamate and GABA release) relationship was observed in several brain sites. Specifically, glutamate in the nucleus accumbens shows a decreasing logarithmic dose response curve. Finally, regression analysis of 11 published reports employing brain microdialysis experiments in 104 alcohol-dependent rats reveals very consistent augmented extracellular glutamate and GABA levels in various brain sites that correlate with the intensity of the withdrawal response were identified. CONCLUSIONS In summary, our results provide standardized basal values for future experimental and in silico studies on neurotransmitter release in the rat brain and may be helpful to understand the effect of ethanol on neurotransmitter release. Furthermore, this study illustrates the benefit of meta-analyses using the generalization of a wide range of preclinical data.
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Affiliation(s)
- Sarah Fliegel
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
| | - Ines Brand
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
| | - Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
| | - Hamid R Noori
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
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19
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Daneault JF, Carignan B, Sadikot AF, Panisset M, Duval C. Drug-induced dyskinesia in Parkinson's disease. Should success in clinical management be a function of improvement of motor repertoire rather than amplitude of dyskinesia? BMC Med 2013; 11:76. [PMID: 23514355 PMCID: PMC3751666 DOI: 10.1186/1741-7015-11-76] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 03/20/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Dyskinesia, a major complication in the treatment of Parkinson's disease (PD), can require prolonged monitoring and complex medical management. DISCUSSION The current paper proposes a new way to view the management of dyskinesia in an integrated fashion. We suggest that dyskinesia be considered as a factor in a signal-to-noise ratio (SNR) equation where the signal is the voluntary movement and the noise is PD symptomatology, including dyskinesia. The goal of clinicians should be to ensure a high SNR in order to maintain or enhance the motor repertoire of patients. To understand why such an approach would be beneficial, we first review mechanisms of dyskinesia, as well as their impact on the quality of life of patients and on the health-care system. Theoretical and practical bases for the SNR approach are then discussed. SUMMARY Clinicians should not only consider the level of motor symptomatology when assessing the efficacy of their treatment strategy, but also breadth of the motor repertoire available to patients.
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Affiliation(s)
- Jean-François Daneault
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec H3A 2B4, Canada
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20
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Lynch S, Sivam SP. Dopamine and GABA Interaction in Basal Ganglia: GABA-A or GABA-B Receptor Stimulation Attenuates L-DOPA-Induced Striatal and Nigral ERK1/2 Signaling in a Rat Model of Parkinson’s Disease. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/jbbs.2013.36050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder, affecting up to 10 million people worldwide. Current treatment primarily involves symptom management with dopaminergic replacement therapy. Levodopa remains the most effective oral treatment, although long-term use is associated with complications such as wearing off, dyskinesias, and on-off fluctuations. Non-dopaminergic medications that improve PD symptoms and motor fluctuations are in demand. Adenosine A2A receptors are abundantly expressed within the basal ganglia and offer a unique target to modify abnormal striatal signaling associated with PD. Preclinical animal models have shown the ability of adenosine A2A receptor antagonists to improve PD motor symptoms, reduce motor fluctuations and dyskinesia, as well as protect against toxin-induced neuronal degeneration. Both istradefylline and preladenant have demonstrated moderate efficacy in reducing off time in PD patients with motor fluctuations. The safety and efficacy of this class of compounds continues to be defined and future studies should focus on non-motor symptoms, dyskinesias, and neuroprotection.
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Affiliation(s)
- Patrick Hickey
- Duke University Medical Center, DUMC Box 3333, Durham, NC 27205, USA.
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22
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Komaki S, Ishikawa K, Arakawa Y. Trk and cAMP-dependent survival activity of adenosine A(2A) agonist CGS21680 on rat motoneurons in culture. Neurosci Lett 2012; 522:21-4. [PMID: 22691937 DOI: 10.1016/j.neulet.2012.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Revised: 05/27/2012] [Accepted: 06/01/2012] [Indexed: 01/01/2023]
Abstract
The survival activity of adenosine A(2A) agonist CGS21680 on motoneurons in culture through the transactivation of neurotrophin receptor TrkB has been reported previously; however, since adenosine A(2A) receptor belongs to a Gs-protein-coupled receptor, we investigated the involvement of the cAMP pathway in the survival activity of CGS21680 using purified motoneurons in culture. CGS21680 alone showed only small survival activity, but the activity was significantly enhanced by the addition of a phosphodiesterase inhibitor, IBMX. This survival activity was partially inhibited by a protein kinase A inhibitor H89 or a neurotrophin receptor tyrosine kinase inhibitor K252a, and was completely inhibited by their combination. These results indicate that the survival activity of CGS21680 on motoneurons is exerted by the mixed effect of the adenylate cyclase-cAMP-PKA pathway and transactivation of Trk neurotrophin receptor. Under conditions in which the maximum survival of motoneurons was supported by sufficient concentrations of brain-derived neurotrophic factor (BDNF), a TrkB ligand, the addition of 100μM AMPA for 3 days led to significant cell death. Treatment with CGS21680 and IBMX protected motoneurons from the toxicity of AMPA, further supporting the presence of a TrkB-independent pathway of CGS21680 activity and suggesting a novel therapeutic approach to motoneuron diseases such as amyotrophic lateral sclerosis.
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Affiliation(s)
- Satoshi Komaki
- Clinical Research Support Center, The University of Tokyo Hospital, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8655, Japan.
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23
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Hodgson RA, Bedard PJ, Varty GB, Kazdoba TM, Di Paolo T, Grzelak ME, Pond AJ, Hadjtahar A, Belanger N, Gregoire L, Dare A, Neustadt BR, Stamford AW, Hunter JC. Preladenant, a selective A(2A) receptor antagonist, is active in primate models of movement disorders. Exp Neurol 2010; 225:384-90. [PMID: 20655910 DOI: 10.1016/j.expneurol.2010.07.011] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 07/14/2010] [Accepted: 07/15/2010] [Indexed: 11/26/2022]
Abstract
Parkinson's Disease (PD) and Extrapyramidal Syndrome (EPS) are movement disorders that result from degeneration of the dopaminergic input to the striatum and chronic inhibition of striatal dopamine D(2) receptors by antipsychotics, respectively. Adenosine A(2A) receptors are selectively localized in the basal ganglia, primarily in the striatopallidal ("indirect") pathway, where they appear to operate in concert with D(2) receptors and have been suggested to drive striatopallidal output balance. In cases of dopaminergic hypofunction, A(2A) receptor activation contributes to the overdrive of the indirect pathway. A(2A) receptor antagonists, therefore, have the potential to restore this inhibitor imbalance. Consequently, A(2A) receptor antagonists have therapeutic potential in diseases of dopaminergic hypofunction such as PD and EPS. Targeting the A(2A) receptor may also be a way to avoid the issues associated with direct dopamine agonists. Recently, preladenant was identified as a potent and highly selective A(2A) receptor antagonist, and has produced a significant improvement in motor function in rodent models of PD. Here we investigate the effects of preladenant in two primate movement disorder models. In MPTP-treated cynomolgus monkeys, preladenant (1 or 3 mg/kg; PO) improved motor ability and did not evoke any dopaminergic-mediated dyskinetic or motor complications. In Cebus apella monkeys with a history of chronic haloperidol treatment, preladenant (0.3-3.0 mg/kg; PO) delayed the onset of EPS symptoms evoked by an acute haloperidol challenge. Collectively, these data support the use of preladenant for the treatment of PD and antipsychotic-induced movement disorders.
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Affiliation(s)
- Robert A Hodgson
- Department of Neurobiology, Merck and Co. Inc., Kenilworth, NJ 07033, USA.
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24
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Lester DB, Rogers TD, Blaha CD. Acetylcholine-dopamine interactions in the pathophysiology and treatment of CNS disorders. CNS Neurosci Ther 2010; 16:137-62. [PMID: 20370804 PMCID: PMC6493877 DOI: 10.1111/j.1755-5949.2010.00142.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Dopaminergic neurons in the substantia nigra pars compacta and ventral tegmental area of the midbrain form the nigrostriatal and mesocorticolimbic dopaminergic pathways that, respectively, project to dorsal and ventral striatum (including prefrontal cortex). These midbrain dopaminergic nuclei and their respective forebrain and cortical target areas are well established as serving a critical role in mediating voluntary motor control, as evidenced in Parkinson's disease, and incentive-motivated behaviors and cognitive functions, as exhibited in drug addiction and schizophrenia, respectively. Although it cannot be disputed that excitatory and inhibitory amino acid-based neurotransmitters, such as glutamate and GABA, play a vital role in modulating activity of midbrain dopaminergic neurons, recent evidence suggests that acetylcholine may be as important in regulating dopaminergic transmission. Midbrain dopaminergic cell tonic and phasic activity is closely dependent upon projections from hindbrain pedunculopontine and the laterodorsal tegmental nuclei, which comprises the only known cholinergic inputs to these neurons. In close coordination with glutamatergic and GABAergic activity, these excitatory cholinergic projections activate nicotinic and muscarinic acetylcholine receptors within the substantia nigra and ventral tegmental area to modulate dopamine transmission in the dorsal/ventral striatum and prefrontal cortex. Additionally, acetylcholine-containing interneurons in the striatum also constitute an important neural substrate to provide further cholinergic modulation of forebrain striatal dopaminergic transmission. In this review, we examine neurological and psychopathological conditions associated with dysfunctions in the interaction of acetylcholine and dopamine and conventional and new pharmacological approaches to treat these disorders.
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Affiliation(s)
- Deranda B Lester
- Department of Psychology, The University of Memphis, Memphis, TN, USA
| | - Tiffany D. Rogers
- Department of Psychology, The University of Memphis, Memphis, TN, USA
| | - Charles D. Blaha
- Department of Psychology, The University of Memphis, Memphis, TN, USA
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25
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Galvan A, Hu X, Smith Y, Wichmann T. Localization and function of GABA transporters in the globus pallidus of parkinsonian monkeys. Exp Neurol 2010; 223:505-15. [PMID: 20138865 DOI: 10.1016/j.expneurol.2010.01.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/10/2010] [Accepted: 01/29/2010] [Indexed: 12/19/2022]
Abstract
The GABA transporters GAT-1 and GAT-3 are abundant in the external and internal segments of the globus pallidus (GPe and GPi, respectively). We have shown that pharmacological blockade of either of these transporters results in decreased neuronal firing, and in elevated levels of extracellular GABA in normal monkeys. We now studied whether the electrophysiologic and biochemical effects of local intra-pallidal injections of GAT-1 and GAT-3 blockers, or the subcellular localization of these transporters, are altered in monkeys rendered parkinsonian by the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The subcellular localization of the transporters in GPe and GPi, studied with electron microscopy immunoperoxidase, was similar to that found in normal animals: i.e., GAT-3 immunoreactivity was mostly confined to glial processes, while GAT-1 labeling was expressed in unmyelinated axons and glial processes. A combined injection/recording device was used to record the extracellular activity of single neurons in GPe and GPi, before, during and after administration of small volumes (1microl) of either the GAT-1 inhibitor, SKF-89976A hydrochloride (720ng), or the GAT-3 inhibitor, (S)-SNAP-5114 (500ng). In GPe, the effects of GAT-1 or GAT-3 blockade were similar to those seen in normal monkeys. However, unlike the findings in the normal state, the firing of most neurons was not affected by blockade of either transporter in GPi. These results suggest that, after dopaminergic depletion, the functions of GABA transporters are altered in GPi; without major changes in their subcellular localization.
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Affiliation(s)
- Adriana Galvan
- Yerkes National Primate Research Center, School of Medicine, Emory University, Atlanta, GA, USA.
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26
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Buck K, Voehringer P, Ferger B. Rapid analysis of GABA and glutamate in microdialysis samples using high performance liquid chromatography and tandem mass spectrometry. J Neurosci Methods 2009; 182:78-84. [PMID: 19505500 DOI: 10.1016/j.jneumeth.2009.05.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 05/28/2009] [Indexed: 11/16/2022]
Abstract
A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method has been established for the rapid and reliable determination of gamma-aminobutyric acid (GABA) and glutamate in brain microdialysates. The microdialysis samples were analysed using a HILIC (hydrophilic interaction liquid chromatography) column, which is able to retain the polar amino acid neurotransmitters. The mobile phase consisted of a binary gradient elution profile comprising 0.1% formic acid in water and acetonitrile. GABA, glutamate as well as the respective internal standards [D(6)]-GABA and [D(5)]-glutamate were detected by a triple quadrupole mass spectrometer in the positive electrospray ionisation mode within a running time of 3 min. The linearity ranged from 1 nM to 10 microM for GABA and 10 nM to 10 microM for glutamate. The limit of quantitation was found to be 1 nM for GABA and 10nM for glutamate (injection volume 10 microl). The present LC-MS/MS method was compared to the classical method for analysis of GABA and glutamate using high performance liquid chromatography (HPLC) and fluorescence detection (FD). Eventually, the feasibility of the LC-MS/MS method was demonstrated using in vivo microdialysis in rats by monitoring changes of the extracellular concentrations of GABA and glutamate in the globus pallidus following stimulation with potassium.
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Affiliation(s)
- Kerstin Buck
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, 88397 Biberach, Germany
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27
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Hauser RA, Shulman LM, Trugman JM, Roberts JW, Mori A, Ballerini R, Sussman NM. Study of istradefylline in patients with Parkinson's disease on levodopa with motor fluctuations. Mov Disord 2009; 23:2177-85. [PMID: 18831530 DOI: 10.1002/mds.22095] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The objective of this study was to evaluate the efficacy, safety, and tolerability of istradefylline 20 mg once daily versus placebo as an adjunct to levodopa in subjects with Parkinson's disease (PD) who have motor fluctuations. Istradefylline (KW-6002) is an adenosine A(2A) receptor antagonist that in primate models of PD improves motor function without causing or worsening dyskinesia. This 12-week, multicenter, double-blind, placebo-controlled, randomized, Phase 3 study of istradefylline was conducted in subjects experiencing an average daily OFF time of at least 3 hours (116 randomized to istradefylline; 115 to placebo). All were on stable levodopa regimens; 90% were also on stable regimens of other anti-Parkinson's medications. Istradefylline-treated subjects had significant placebo-corrected reductions in daily OFF time from baseline to endpoint: 4.6% (P = 0.03) and 0.7 hours (P = 0.03). For ON time with troublesome dyskinesia, the changes between istradefylline and placebo were not significant. Istradefylline was well tolerated, with 6 (5.2%) istradefylline-treated and 7 (6.1%) placebo-treated subjects withdrawing from the study because of adverse events. Dyskinesia, lightheadedness, tremor, constipation, and weight decrease were reported more often with istradefylline than placebo. We conclude that istradefylline is well tolerated and significantly reduces OFF time as an adjunct to levodopa in PD subjects with motor fluctuations.
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Affiliation(s)
- Robert A Hauser
- Department of Neurology, University of South Florida, Tampa, Florida 33606, USA.
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28
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Abstract
The drug treatment of Parkinson's disease (PD) is accompanied by a loss of drug efficacy, the onset of motor complications, lack of effect on non-motor symptoms, and a failure to modify disease progression. As a consequence, novel approaches to therapy are sought, and adenosine A(2A) receptors (A(2A)ARs) provide a viable target. A(2A)ARs are highly localized to the basal ganglia and specifically to the indirect output pathway, which is highly important in the control of voluntary movement. A(2A)AR antagonists can modulate gamma-aminobutyric acid (GABA) and glutamate release in basal ganglia and other key neurotransmitters that modulate motor activity. In both rodent and primate models of PD, A(2A)AR antagonists produce alterations in motor behavior, either alone or in combination with dopaminergic drugs, which suggest that they will be effective in the symptomatic treatment of PD. In clinical trials, the A(2A)AR antagonist istradefylline reduces "off" time in patients with PD receiving optimal dopaminergic therapy. However, these effects have proven difficult to demonstrate on a consistent basis, and further clinical trials are required to establish the clinical utility of this drug class. Based on preclinical studies, A(2A)AR antagonists may also be neuroprotective and have utility in the treatment of neuropsychiatric disorders. We are only now starting to explore the range of potential uses of A(2A)AR antagonists in central nervous system disorders, and their full utility is still to be uncovered.
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Affiliation(s)
- Micaela Morelli
- Department of Toxicology and Center of Excellence for Neurobiology of Addiction, University of Cagliari, 09124 Cagliari, Italy.
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29
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Di Giovanni G, Esposito E, Di Matteo V. In vivo microdialysis in Parkinson's research. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2009:223-43. [PMID: 20411781 DOI: 10.1007/978-3-211-92660-4_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder that is primarily characterized by the degeneration of dopamine (DA) neurons in the nigrostriatal system, which in turn produces profound neurochemical changes within the basal ganglia, representing the neural substrate for parkinsonian motor symptoms. The pathogenesis of the disease is still not completely understood, but environmental and genetic factors are thought to play important roles. Research into the pathogenesis and the development of new therapeutic intervention strategies that will slow or stop the progression of the disease in human has rapidly advanced by the use of neurotoxins that specifically target DA neurons. Over the years, a broad variety of experimental models of the disease has been developed and applied in diverse animal species. The two most common toxin models used employ 6-hydroxydopamine (6-OHDA) and the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/1-methyl-4-phenilpyridinium ion (MPTP/MPP+), either given systemically or locally applied into the nigrostriatal pathway, to resemble PD features in animals. Both neurotoxins selectively and rapidly destroy catecolaminergic neurons, although with different mechanisms. Since in vivo microdialysis coupled to high-performance liquid chromatography is an established technique for studying physiological, pharmacological, and pathological changes of a wide range of low molecular weight substances in the brain extracellular fluid, here we review the most prominent animal and human data obtained by the use of this technique in PD research.
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Affiliation(s)
- Giuseppe Di Giovanni
- Dipartimento di Medicina Sperimentale, Sezione di Fisiologia Umana, G. Pagano, Universitá degli Studi di Palermo, 90134, Palermo, Italy
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Simola N, Fenu S, Baraldi PG, Tabrizi MA, Morelli M. Blockade of globus pallidus adenosine A(2A) receptors displays antiparkinsonian activity in 6-hydroxydopamine-lesioned rats treated with D(1) or D(2) dopamine receptor agonists. Synapse 2008; 62:345-51. [PMID: 18297692 DOI: 10.1002/syn.20504] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have recently demonstrated how antagonism of adenosine A(2A) receptors within the globus pallidus (GP) ipsilateral to dopaminergic denervation potentiates contralateral rotational behavior induced by the dopamine precursor L-DOPA in 6-hydroxydopamine-lesioned hemiparkinsonian rats. To further characterize the influence of pallidal A(2A) receptor blockade on the motor stimulant effects elicited by dopamine receptor activation, hemiparkinsonian rats were infused with the water-soluble A(2A) antagonist SCH BT2 in the GP, alone or in combination with systemic administration of either SKF 38393 or quinpirole, to stimulate dopamine D(1) or D(2) receptors, respectively. SCH BT2 alone (5 mug/1 mul) neither altered motor behavior nor produced postural asymmetry. In contrast, the contralateral rotations elicited by SKF 38393 (1.5 mg/kg) as well as quinpirole (0.05 mg/kg) were potentiated by the concomitant intrapallidal infusion of SCH BT2. The results of this study demonstrate that blockade of pallidal A(2A) receptors exerts a facilitatory influence on the motor effects produced by the selective stimulation of either D(1) or D(2) dopamine receptors in hemiparkinsonian rats and suggest an involvement of GP in the antiparkinsonian activity of A(2A) receptor antagonists.
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Affiliation(s)
- Nicola Simola
- Department of Toxicology, University of Cagliari, 09124 Cagliari, Italy
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Galvan A, Wichmann T. GABAergic circuits in the basal ganglia and movement disorders. PROGRESS IN BRAIN RESEARCH 2007; 160:287-312. [PMID: 17499121 DOI: 10.1016/s0079-6123(06)60017-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
GABA is the major inhibitory neurotransmitter in the basal ganglia, and GABAergic pathways dominate information processing in most areas of these structures. It is therefore not surprising that abnormalities of GABAergic transmission are key elements in pathophysiologic models of movement disorders involving the basal ganglia. These include hypokinetic diseases such as Parkinson's disease, and hyperkinetic diseases, such as Huntington's disease or hemiballism. In this chapter, we will briefly review the major anatomic features of the GABAergic pathways in the basal ganglia, and then describe in greater detail the changes of GABAergic transmission, which are known to occur in movement disorders.
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Affiliation(s)
- Adriana Galvan
- Department of Neurology, School of Medicine and Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322, USA.
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DeCerce J, Smith LF, Gonzalez W, Sussman NM. Effectiveness and tolerability of istradefylline for the treatment of restless legs syndrome: an exploratory study in five female patients. CURRENT THERAPEUTIC RESEARCH 2007; 68:349-59. [PMID: 24692766 PMCID: PMC3969964 DOI: 10.1016/j.curtheres.2007.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/28/2007] [Indexed: 10/22/2022]
Abstract
BACKGROUND Studies of istradefylline (KW6002), an adenosine A2A-receptor antagonist, have provided evidence of its efficacy as a nondopaminergic antiparkinsonian drug. Antiparkinsonian drugs have also had efficacy in treating restless legs syndrome (RLS). OBJECTIVES The aims of this study were to assess the effectiveness and tolerability of istradefylline in the treatment of RLS. METHODS This was a single-center, multiparametric, prospective trial of istradefylline as a treatment for moderate to severe idiopathic RLS. It was conducted at the Shands/Jacksonville Sleep Disorders Center, University of Florida, Jacksonville, Florida, from March 2003 to October 2003. Patients received a single PO 80-mg dose QD of istradefylline in the late afternoon or early evening for 6 weeks. Appropriate tolerability evaluations (ie, vital assessments, physical examination, clinical laboratory tests, and electrocardiogram) were performed at screening, while on study drug, and after withdrawal of study drug. RESULTS Fifteen participants (mean [SD] age, 61 [7.1] years; range, 50-69 years) were screened for enrollment. The mean duration of RLS was 18 years. Of the 15 potential patients, 6 did not meet entry criteria, 2 withdrew consent, 1 had not completed baseline procedures at the time of study suspension, and 1 was excluded for administrative reasons. Therefore, a total of 5 patients received the study drug. Of these, 3 (60%) patients responded favorably to istradefylline treatment. Improvement in the periodic limb movement index was observed in 3 patients compared with baseline (patients 2, 4, and 5 [index score: 6, 4, 9 vs 50, 35, 18, respectively]). Improvement in the International RLS Rating Scale scores was observed in 3 patients compared with baseline (patients 2, 4, and 5 [index score: 7, 23, 9 vs 35, 25, 20, respectively]). There was a return to baseline severity in 2 of the 3 patients after withdrawal of study drug. Improvement in RLS symptoms was observed in 3 patients treated with istradefylline for 6 weeks. A clinical worsening of baseline insomnia was observed in 2 patients. CONCLUSIONS Although we could not definitively conclude a beneficial effect based on this small exploratory trial, we found the data to be encouraging. The study drug was well tolerated. Further study of this compound in the treatment of RLS is justified.
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Affiliation(s)
- John DeCerce
- Shands/Jacksonville Sleep Disorders Center, College of Medicine, University of Florida, Jacksonville, Florida
| | - Lisa F. Smith
- Shands/Jacksonville Sleep Disorders Center, College of Medicine, University of Florida, Jacksonville, Florida
| | - Walter Gonzalez
- Shands/Jacksonville Sleep Disorders Center, College of Medicine, University of Florida, Jacksonville, Florida
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Jenner P. Istradefylline, a novel adenosine A2A receptor antagonist, for the treatment of Parkinson's disease. Expert Opin Investig Drugs 2006; 14:729-38. [PMID: 16004599 DOI: 10.1517/13543784.14.6.729] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Dopamine replacement therapy effectively treats the early motor symptoms of Parkinson's disease (PD). However, its association with the development of motor complications limits its usefulness in late stages of the disease. Adenosine A(2A) receptors are localised to the indirect striatal output function and control motor behaviour. They are active in predictive experimental models of PD and appear to be promising as the first major non-dopaminergic therapy for PD. Istradefylline is a novel adenosine A(2A) receptor antagonist currently in Phase III clinical trials for efficacy in patients with PD; results from Phase II clinical trials demonstrated that it provides a clinically meaningful reduction in 'off' time and an increased 'on' time with non-troublesome dyskinesia in levodopa-treated patients with established motor complications, and is safe and well tolerated.
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Affiliation(s)
- Peter Jenner
- Neurodegenerative Diseases Research Centre, GKT School of Biomedical Sciences, King's College, London SE1 1UL, UK.
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Gomez-Ramirez J, Johnston TH, Visanji NP, Fox SH, Brotchie JM. Histamine H3 receptor agonists reduce L-dopa-induced chorea, but not dystonia, in the MPTP-lesioned nonhuman primate model of Parkinson's disease. Mov Disord 2006; 21:839-46. [PMID: 16532454 DOI: 10.1002/mds.20828] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
L-dopa-induced dyskinesia (LID) remains a major complication of the treatment of Parkinson's disease. The neural mechanisms underlying LID are thought to involve overactivity of striatal glutamatergic neurotransmission, with resultant underactivation of the output regions of the basal ganglia. Histamine H3 heteroreceptors can reduce glutamate and gamma-aminobutyric acid (GABA) transmission in the striatum and substantia nigra reticulata, respectively. Thus, we tested whether the histamine H3 receptor agonists immepip and imetit can alleviate LID in the MPTP-lesioned marmoset model of Parkinson's disease. Coadministration of immepip (1 mg/kg) with L-dopa (15 mg/kg) was associated with significantly less total dyskinesia than L-dopa alone. When dyskinesia was separately rated as chorea and dystonia, coadministration of L-dopa with either immepip or imetit (both 10 mg/kg) significantly reduced chorea but had no effect on dystonia. The antidyskinetic actions of the H3 agonists were not accompanied by alteration of the antiparkinsonian actions of L-dopa. However, immepip (10 mg/kg), when administered as monotherapy, significantly increased parkinsonian disability compared to vehicle. Overall, the results obtained in this study suggest that histamine H3 receptors may be involved in the neural mechanisms underlying L-dopa-induced dyskinesia in Parkinson's disease.
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Affiliation(s)
- Jordi Gomez-Ramirez
- Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
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Morissette M, Dridi M, Calon F, Hadj Tahar A, Meltzer LT, Bédard PJ, Di Paolo T. Prevention of dyskinesia by an NMDA receptor antagonist in MPTP monkeys: Effect on adenosine A2A receptors. Synapse 2006; 60:239-50. [PMID: 16739115 DOI: 10.1002/syn.20295] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Adenosine A(2A) receptors (A(2A)R) have received increasing attention for the treatment of L-DOPA-induced dyskinesias in Parkinson disease. In the present study, A(2A)R messenger RNA (mRNA) and receptor-specific binding in the brain of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) monkeys were studied after treatment with L-DOPA and a selective NR1A/2B NMDA receptor antagonist, CI-1041. Four MPTP monkeys received L-DOPA/benserazide and all developed dyskinesias, whereas among the four MPTP monkeys who additionally received CI-1041, only one developed mild dyskinesias. Four normal monkeys and four MPTP-treated monkeys were also studied. All MPTP monkeys had similar striatal dopamine (DA) denervation. A(2A)R mRNA levels, measured by in situ hybridization, were increased in the rostral lateral caudate and putamen of saline-treated MPTP monkeys as well as in the caudal lateral and medial putamen when compared with those of controls. A(2A)R mRNA levels remained elevated in the rostral caudate and putamen of L-DOPA-treated MPTP monkeys when compared with those of controls. A(2A)R mRNA levels of L-DOPA + CI-1041-treated monkeys were at control levels and decreased in the lateral rostral caudate and caudal putamen when compared with those of L-DOPA-treated and saline-treated MPTP monkeys respectively. No change was measured in the caudal medial putamen and caudate nucleus. A(2A)Rs labeled by autoradiography with [(3)H]SCH-58261 had lower level in the L-DOPA + CI-1041-treated MPTP monkeys compared with saline- or L-DOPA-treated MPTP and control monkeys in the rostral lateral and medial caudate and the putamen. No effect of lesion or L-DOPA treatment was measured on [(3)H]SCH-58261-specific binding. These findings suggest that blockade of NMDA receptors could prevent the development of dyskinesias by altering A(2A)Rs.
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Affiliation(s)
- Marc Morissette
- Molecular Endocrinology and Oncology Research Centre, Laval University Medical Centre (CHUL), Quebec, Canada
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Touchon JC, Holmer HK, Moore C, McKee BL, Frederickson J, Meshul CK. Apomorphine-induced alterations in striatal and substantia nigra pars reticulata glutamate following unilateral loss of striatal dopamine. Exp Neurol 2005; 193:131-40. [PMID: 15817272 DOI: 10.1016/j.expneurol.2004.11.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Revised: 11/13/2004] [Accepted: 11/24/2004] [Indexed: 10/25/2022]
Abstract
We have reported time-dependent changes in extracellular glutamate within the striatum at 1 and 3 months following a unilateral lesion of the nigrostriatal pathway using the neurotoxin, 6-hydroxydopamine (6-OHDA) (Meshul, C.K., Emre, N., Nakamura, C.M., Allen, C., Donohue, M.K., Buckman, J.F., 1999. Time-dependent changes in striatal glutamate synapses following a 6-hydroxydopamine lesion. Neurosci. 88, 1-16.). The aim of the present study was to determine the effects of such a lesion on glutamate within the substantia nigra pars reticulata (SN-PR) and the effect of subchronic administration of the dopamine D-1/D-2 agonist, apomorphine, on extracellular glutamate within both the striatum and the SN-PR using in vivo microdialysis. One month after the lesion, there is an increase in extracellular glutamate within the striatum and apomorphine treatment leads to a further increase. Within the SN-PR, a loss of striatal dopamine leads to a decrease in extracellular glutamate, while apomorphine treatment leads to a further decrease in nigral glutamate. Three months after a 6-OHDA lesion, there is a decrease in extracellular striatal glutamate, with apomorphine administration leading to essentially no further change in glutamate. The loss of striatal dopamine increased extracellular glutamate within the SN-PR while apomorphine administration resulted in a decrease in extracellular glutamate back to the value observed in the control group. The data suggests that the increase in striatal glutamate 1 month following a 6-OHDA lesion alone or following subchronic apomorphine is consistent with the hypothesis that a decrease in glutamate within the SN-PR leads to activation of the thalamo-cortico-striatal pathway. The decrease in striatal glutamate 3 months after a nigrostriatal lesion is also consistent with the observed increase in extracellular glutamate within the SN-PR, thus leading to a decrease in output of the thalamo-cortico-striatal pathway.
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Affiliation(s)
- Justin C Touchon
- Research Services, Neurocytology Lab, VA Medical Center, 3710 S.W. Veterans Hospital Road, Portland, OR 97239, USA
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Tang CM, Hoerning A, Büscher R, O'Connor DT, Ratjen F, Grasemann H, Insel PA. Human adenosine 2B receptor: SNP discovery and evaluation of expression in patients with cystic fibrosis. Pharmacogenet Genomics 2005; 15:321-7. [PMID: 15864133 DOI: 10.1097/01213011-200505000-00007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVES AND METHODS We analyzed the adenosine 2B (A2B) receptor gene, which consists of two exons, for single nucleotide polymorphisms (SNPs) and tested the hypothesis that coding sequence polymorphisms in the gene contribute to disease state in patients with cystic fibrosis (CF). Using PCR and restriction fragment length polymorphism (RFLP) analysis, we assessed 53 American subjects of mixed ethnicity, 64 European Caucasian control subjects and 148 Caucasian patients with CF for A2B SNPs. RESULTS We identified one SNP in the 5' untranslated region (UTR) and seven SNPs in the open reading frame. One SNP was identified in the coding region of a German patient with CF but in none of the American subjects. No other SNPs were found in CF patients. A nonsynonymous SNP was identified in exon 2 of the German controls with an allelic frequency of 11%. The US subjects were of mixed ethnicity and most frequently (10.4%) had a SNP in the 5'UTR; 7 coding SNPs occurred in <3%. All SNPs other than the Leu96Phe and Gly136Arg variants were found only in African-Americans. Of the 26 African-Americans who were genotyped, 42% were hypertensive but the study group was too small to show an association between blood pressure status and SNP expression. CONCLUSIONS The data show that SNPs in the A2B receptor gene are much more frequent in African-Americans than in Caucasians and that German Caucasians, but not African-Americans, express Gly136Arg. None of the SNPs identified in A2B receptors are likely to be modifiers in CF.
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Affiliation(s)
- Chih-Min Tang
- Department of Pharmacology, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA
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Xu K, Bastia E, Schwarzschild M. Therapeutic potential of adenosine A2A receptor antagonists in Parkinson's disease. Pharmacol Ther 2005; 105:267-310. [PMID: 15737407 DOI: 10.1016/j.pharmthera.2004.10.007] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 10/14/2004] [Indexed: 10/26/2022]
Abstract
In the pursuit of improved treatments for Parkinson's disease (PD), the adenosine A(2A) receptor has emerged as an attractive nondopaminergic target. Based on the compelling behavioral pharmacology and selective basal ganglia expression of this G-protein-coupled receptor, its antagonists are now crossing the threshold of clinical development as adjunctive symptomatic treatment for relatively advanced PD. The antiparkinsonian potential of A(2A) antagonism has been boosted further by recent preclinical evidence that A(2A) antagonists might favorably alter the course as well as the symptoms of the disease. Convergent epidemiological and laboratory data have suggested that A(2A) blockade may confer neuroprotection against the underlying dopaminergic neuron degeneration. In addition, rodent and nonhuman primate studies have raised the possibility that A(2A) receptor activation contributes to the pathophysiology of dyskinesias-problematic motor complications of standard PD therapy--and that A(2A) antagonism might help prevent them. Realistically, despite being targeted to basal ganglia pathophysiology, A(2A) antagonists may be expected to have other beneficial and adverse effects elsewhere in the central nervous system (e.g., on mood and sleep) and in the periphery (e.g., on immune and inflammatory processes). The thoughtful design of new clinical trials of A(2A) antagonists should take into consideration these counterbalancing hopes and concerns and may do well to shift toward a broader set of disease-modifying as well as symptomatic indications in early PD.
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Affiliation(s)
- Kui Xu
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Charlestown, MA 02129, USA
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Kase H, Mori A, Jenner P. Adenosine A2A-receptor antagonists: beyond dopaminergic therapies for Parkinson's disease. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ddstr.2004.08.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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