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Jenner P, Kanda T, Mori A. How and why the adenosine A 2A receptor became a target for Parkinson's disease therapy. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 170:73-104. [PMID: 37741697 DOI: 10.1016/bs.irn.2023.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/25/2023]
Abstract
Dopaminergic therapy for Parkinson's disease has revolutionised the treatment of the motor symptoms of the illness. However, it does not alleviate all components of the motor deficits and has only limited effects on non-motor symptoms. For this reason, alternative non-dopaminergic approaches to treatment have been sought and the adenosine A2A receptor provided a novel target for symptomatic therapy both within the basal ganglia and elsewhere in the brain. Despite an impressive preclinical profile that would indicate a clear role for adenosine A2A antagonists in the treatment of Parkinson's disease, the road to clinical use has been long and full of difficulties. Some aspects of the drugs preclinical profile have not translated into clinical effectiveness and not all the clinical studies undertaken have had a positive outcome. The reasons for this will be explored and suggestions made for the further development of this drug class in the treatment of Parkinson's disease. However, one adenosine A2A antagonist, namely istradefylline has been introduced successfully for the treatment of late-stage Parkinson's disease in two major areas of the world and has become a commercial success through offering the first non-dopaminergic approach to the treatment of unmet need to be introduced in several decades.
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Affiliation(s)
- Peter Jenner
- Institute of Pharmaceutical Sciences, King's College London, London, United Kingdom.
| | - Tomoyuki Kanda
- Kyowa Kirin Co., Ltd., Otemachi. Chiyoda-ku, Tokyo, Japan
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Waggan I, Rissanen E, Tuisku J, Joutsa J, Helin S, Parkkola R, Rinne JO, Airas L. Adenosine A 2A receptor availability in patients with early- and moderate-stage Parkinson's disease. J Neurol 2023; 270:300-310. [PMID: 36053386 DOI: 10.1007/s00415-022-11342-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 08/06/2022] [Accepted: 08/17/2022] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Adenosine 2A (A2A) receptors co-localize with dopamine D2 receptors in striatopallidal medium spiny neurons of the indirect pathway. A2A receptor activation in the striatum or pallidum decreases D2 signaling. In contrast, A2A receptor antagonism may help potentiate it. Furthermore, previous PET studies have shown increased A2A receptor availability in striatum of late-stage PD patients with dyskinesia. However, human in vivo evidence for striatal A2A receptor availability in early-stage PD is limited. This study aimed to investigate possible differences in A2A receptor availability in the striatum and pallidum of early- and moderate-stage PD patients without dyskinesias. METHODS Brain MRI and PET with [11C]TMSX radioligand, targeting A2A receptors, was performed in 9 patients with early- and 9 with moderate-stage PD without dyskinesia and in 6 healthy controls. Distribution volume ratios (DVR) were calculated to assess specific [11C]TMSX binding in caudate, putamen and pallidum. RESULTS A2A receptor availability (DVR) was decreased in the bilateral caudate of early-stage PD patients when compared with healthy controls (P = 0.02). Conversely, DVR was increased bilaterally in the pallidum of moderate-stage PD patients compared to healthy controls (P = 0.03). Increased mean striatal DVR correlated with higher motor symptom severity ([Formula: see text] = 0.47, P = 0.02). CONCLUSION Our results imply regional and disease stage-dependent changes in A2A receptor signaling in PD pathophysiology and in response to dopaminergic medication.
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Affiliation(s)
- Imran Waggan
- Turku PET Centre, University of Turku, Itäinen Pitkäkatu 4A, 6th floor, 6007, 20520, Turku, Finland.
| | - Eero Rissanen
- Turku PET Centre, University of Turku, Itäinen Pitkäkatu 4A, 6th floor, 6007, 20520, Turku, Finland
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Jouni Tuisku
- Turku PET Centre, University of Turku, Itäinen Pitkäkatu 4A, 6th floor, 6007, 20520, Turku, Finland
| | - Juho Joutsa
- Turku PET Centre, University of Turku, Itäinen Pitkäkatu 4A, 6th floor, 6007, 20520, Turku, Finland
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Semi Helin
- Turku PET Centre, University of Turku, Itäinen Pitkäkatu 4A, 6th floor, 6007, 20520, Turku, Finland
| | - Riitta Parkkola
- Department of Radiology, Turku University Hospital and University of Turku, Turku, Finland
| | - Juha O Rinne
- Turku PET Centre, University of Turku, Itäinen Pitkäkatu 4A, 6th floor, 6007, 20520, Turku, Finland
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Laura Airas
- Turku PET Centre, University of Turku, Itäinen Pitkäkatu 4A, 6th floor, 6007, 20520, Turku, Finland
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
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Waggan I, Rissanen E, Tuisku J, Matilainen M, Helin S, Parkkola R, Rinne JO, Airas L. Effect of dopaminergic medication on adenosine 2A receptor availability in patients with Parkinson's disease. Parkinsonism Relat Disord 2021; 86:40-44. [PMID: 33831661 DOI: 10.1016/j.parkreldis.2021.03.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To assess the necessity of withdrawing dopaminergic medication in Parkinson's disease (PD) patients for accurate estimation of adenosine 2A receptor (A2AR) availability using [11C]TMSX PET imaging. This was accomplished by studying the short-term effect of the cessation of dopaminergic medication on A2AR availability in non-dyskinetic patients with PD treated with dopaminergic medication. METHODS Eight PD patients (age 67.9 ± 5.6 years; 6 men, 2 women) without dyskinesia were enrolled in this study. A2AR availability was measured using PET imaging with a [7-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine ([11C]TMSX) radioligand after a short term cessation of dopaminergic medication (12hrs for levodopa, 24hrs for dopamine agonists and MAO-B inhibitors). Repeated PET imaging was performed while the patients were back 'on' their regular dopaminergic medication (median 13 days after first imaging). Conventional MRI was acquired for anatomical reference. Specific binding of [11C]TMSX was quantified as distribution volume ratios (DVR) for caudate, pallidum and putamen using Logan graphical method with clustered gray matter reference region. RESULTS No significant differences were observed for the DVRs in all three striatal regions between 'on' and 'off' medication states. Strong correlations were also observed between the two states. Statistical equivalence was found in pallidum (TOST equivalence test, p = 0.045) and putamen (TOST equivalence test, p = 0.022), but not in caudate DVR (TOST equivalence test, p = 0.201) between the two medication states. CONCLUSIONS Our results show that dopaminergic medication has no significant short-term effect on the availability of A2A receptors in putamen and pallidum of patients with PD. However, relatively poor repeatability was demonstrated in the caudate.
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Affiliation(s)
- Imran Waggan
- Turku PET Centre, University of Turku, Turku, Finland; Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland.
| | - Eero Rissanen
- Turku PET Centre, University of Turku, Turku, Finland; Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland
| | - Jouni Tuisku
- Turku PET Centre, University of Turku, Turku, Finland
| | | | - Semi Helin
- Turku PET Centre, University of Turku, Turku, Finland
| | - Riitta Parkkola
- Turku PET Centre, University of Turku, Turku, Finland; Radiology Department, Division of Medical Imaging, Turku University Hospital, Turku, Finland
| | - Juha O Rinne
- Turku PET Centre, University of Turku, Turku, Finland; Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland
| | - Laura Airas
- Turku PET Centre, University of Turku, Turku, Finland; Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland
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Ntetsika T, Papathoma PE, Markaki I. Novel targeted therapies for Parkinson's disease. Mol Med 2021; 27:17. [PMID: 33632120 PMCID: PMC7905684 DOI: 10.1186/s10020-021-00279-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/03/2021] [Accepted: 02/08/2021] [Indexed: 02/07/2023] Open
Abstract
Parkinson’s disease (PD) is the second more common neurodegenerative disease with increasing incidence worldwide associated to the population ageing. Despite increasing awareness and significant research advancements, treatment options comprise dopamine repleting, symptomatic therapies that have significantly increased quality of life and life expectancy, but no therapies that halt or reverse disease progression, which remain a great, unmet goal in PD research. Large biomarker development programs are undertaken to identify disease signatures that will improve patient selection and outcome measures in clinical trials. In this review, we summarize PD-related mechanisms that can serve as targets of therapeutic interventions aiming to slow or modify disease progression, as well as previous and ongoing clinical trials in each field, and discuss future perspectives.
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Affiliation(s)
- Theodora Ntetsika
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Center of Neurology, Academic Specialist Center, Solnavägen 1E, 113 65, Stockholm, Sweden
| | - Paraskevi-Evita Papathoma
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Neurology, Danderyd Hospital Stockholm, Stockholm, Sweden
| | - Ioanna Markaki
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden. .,Center of Neurology, Academic Specialist Center, Solnavägen 1E, 113 65, Stockholm, Sweden.
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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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Glaser T, Andrejew R, Oliveira-Giacomelli Á, Ribeiro DE, Bonfim Marques L, Ye Q, Ren WJ, Semyanov A, Illes P, Tang Y, Ulrich H. Purinergic Receptors in Basal Ganglia Diseases: Shared Molecular Mechanisms between Huntington's and Parkinson's Disease. Neurosci Bull 2020; 36:1299-1314. [PMID: 33026587 PMCID: PMC7674528 DOI: 10.1007/s12264-020-00582-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 05/30/2020] [Indexed: 12/22/2022] Open
Abstract
Huntington's (HD) and Parkinson's diseases (PD) are neurodegenerative disorders caused by the death of GABAergic and dopaminergic neurons in the basal ganglia leading to hyperkinetic and hypokinetic symptoms, respectively. We review here the participation of purinergic receptors through intracellular Ca2+ signaling in these neurodegenerative diseases. The adenosine A2A receptor stimulates striatopallidal GABAergic neurons, resulting in inhibitory actions on GABAergic neurons of the globus pallidus. A2A and dopamine D2 receptors form functional heteromeric complexes inducing allosteric inhibition, and A2A receptor activation results in motor inhibition. Furthermore, the A2A receptor physically and functionally interacts with glutamate receptors, mainly with the mGlu5 receptor subtype. This interaction facilitates glutamate release, resulting in NMDA glutamate receptor activation and an increase of Ca2+ influx. P2X7 receptor activation also promotes glutamate release and neuronal damage. Thus, modulation of purinergic receptor activity, such as A2A and P2X7 receptors, and subsequent aberrant Ca2+ signaling, might present interesting therapeutic potential for HD and PD.
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Affiliation(s)
- Talita Glaser
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-000, Brazil
| | - Roberta Andrejew
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-000, Brazil
| | - Ágatha Oliveira-Giacomelli
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-000, Brazil
| | - Deidiane Elisa Ribeiro
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-000, Brazil
| | - Lucas Bonfim Marques
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-000, Brazil
| | - Qing Ye
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-000, Brazil
- Key Laboratory of Sichuan Province for Acupuncture and Chronobiology, Chengdu, 610075, China
| | - Wen-Jing Ren
- Key Laboratory of Sichuan Province for Acupuncture and Chronobiology, Chengdu, 610075, China
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, 04107, Germany
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
- Sechenov First Moscow State Medical University, Moscow, 119992, Russia
| | - Peter Illes
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, 04107, Germany
- International Collaborative Centre on Big Science Plan for Purine Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Yong Tang
- Key Laboratory of Sichuan Province for Acupuncture and Chronobiology, Chengdu, 610075, China
- International Collaborative Centre on Big Science Plan for Purine Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-000, Brazil.
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7
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Jenner P, Mori A, Kanda T. Can adenosine A2A receptor antagonists be used to treat cognitive impairment, depression or excessive sleepiness in Parkinson's disease? Parkinsonism Relat Disord 2020; 80 Suppl 1:S28-S36. [DOI: 10.1016/j.parkreldis.2020.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/15/2020] [Indexed: 01/29/2023]
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Yang D, Ding C, Qi G, Feldmeyer D. Cholinergic and Adenosinergic Modulation of Synaptic Release. Neuroscience 2020; 456:114-130. [PMID: 32540364 DOI: 10.1016/j.neuroscience.2020.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/29/2020] [Accepted: 06/01/2020] [Indexed: 01/14/2023]
Abstract
In this review we will discuss the effect of two neuromodulatory transmitters, acetylcholine (ACh) and adenosine, on the synaptic release probability and short-term synaptic plasticity. ACh and adenosine differ fundamentally in the way they are released into the extracellular space. ACh is released mostly from synaptic terminals and axonal bouton of cholinergic neurons in the basal forebrain (BF). Its mode of action on synaptic release probability is complex because it activate both ligand-gated ion channels, so-called nicotinic ACh receptors and G-protein coupled muscarinic ACh receptors. In contrast, adenosine is released from both neurons and glia via nucleoside transporters or diffusion over the cell membrane in a non-vesicular, non-synaptic fashion; its receptors are exclusively G-protein coupled receptors. We show that ACh and adenosine effects are highly specific for an identified synaptic connection and depend mostly on the presynaptic but also on the postsynaptic receptor type and discuss the functional implications of these differences.
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Affiliation(s)
- Danqing Yang
- Research Centre Juelich, Institute of Neuroscience and Medicine 10, Leo-Brandt-Strasse, Juelich, Germany
| | - Chao Ding
- Research Centre Juelich, Institute of Neuroscience and Medicine 10, Leo-Brandt-Strasse, Juelich, Germany
| | - Guanxiao Qi
- Research Centre Juelich, Institute of Neuroscience and Medicine 10, Leo-Brandt-Strasse, Juelich, Germany
| | - Dirk Feldmeyer
- Research Centre Juelich, Institute of Neuroscience and Medicine 10, Leo-Brandt-Strasse, Juelich, Germany; RWTH Aachen University Hospital, Pauwelsstrasse 30, Aachen, Germany; Jülich-Aachen Research Alliance Brain - JARA Brain, Germany.
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9
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Diao HL, Xue Y, Han XH, Wang SY, Liu C, Chen WF, Chen L. Adenosine A 2A Receptor Modulates the Activity of Globus Pallidus Neurons in Rats. Front Physiol 2017; 8:897. [PMID: 29163226 PMCID: PMC5682020 DOI: 10.3389/fphys.2017.00897] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 10/24/2017] [Indexed: 12/23/2022] Open
Abstract
The globus pallidus is a central nucleus in the basal ganglia motor control circuit. Morphological studies have revealed the expression of adenosine A2A receptors in the globus pallidus. To determine the modulation of adenosine A2A receptors on the activity of pallidal neurons in both normal and parkinsonian rats, in vivo electrophysiological and behavioral tests were performed in the present study. The extracellular single unit recordings showed that micro-pressure administration of adenosine A2A receptor agonist, CGS21680, regulated the pallidal firing activity. GABAergic neurotransmission was involved in CGS21680-induced modulation of pallidal neurons via a PKA pathway. Furthermore, application of two adenosine A2A receptor antagonists, KW6002 or SCH442416, mainly increased the spontaneous firing of pallidal neurons, suggesting that endogenous adenosine system modulates the activity of pallidal neurons through adenosine A2A receptors. Finally, elevated body swing test (EBST) showed that intrapallidal microinjection of adenosine A2A receptor agonist/antagonist induced ipsilateral/contralateral-biased swing, respectively. In addition, the electrophysiological and behavioral findings also revealed that activation of dopamine D2 receptors by quinpirole strengthened KW6002/SCH442416-induced excitation of pallidal activity. Co-application of quinpirole with KW6002 or SCH442416 alleviated biased swing in hemi-parkinsonian rats. Based on the present findings, we concluded that pallidal adenosine A2A receptors may be potentially useful in the treatment of Parkinson's disease.
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Affiliation(s)
- Hui-Ling Diao
- Department of Physiology, Qingdao University, Qingdao, China.,Department of Physiology, Binzhou Medical University, Yantai, China
| | - Yan Xue
- Department of Physiology, Qingdao University, Qingdao, China
| | - Xiao-Hua Han
- Department of Physiology, Qingdao University, Qingdao, China
| | - Shuang-Yan Wang
- Department of Physiology, Qingdao University, Qingdao, China.,Department of Anatomy, Qingdao University, Qingdao, China
| | - Cui Liu
- Department of Physiology, Qingdao University, Qingdao, China
| | - Wen-Fang Chen
- Department of Physiology, Qingdao University, Qingdao, China
| | - Lei Chen
- Department of Physiology, Qingdao University, Qingdao, China
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Yin SB, Zhang XG, Chen S, Yang WT, Zheng XW, Zheng GQ. Adenosine A 2A Receptor Gene Knockout Prevents l-3,4-Dihydroxyphenylalanine-Induced Dyskinesia by Downregulation of Striatal GAD67 in 6-OHDA-Lesioned Parkinson's Mice. Front Neurol 2017; 8:88. [PMID: 28377741 PMCID: PMC5359221 DOI: 10.3389/fneur.2017.00088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 02/24/2017] [Indexed: 11/29/2022] Open
Abstract
l-3,4-Dihydroxyphenylalanine (l-DOPA) remains the primary pharmacological agent for the symptomatic treatment of Parkinson’s disease (PD). However, the development of l-DOPA-induced dyskinesia (LID) limits the long-term use of l-DOPA for PD patients. Some data have reported that adenosine A2A receptor (A2AR) antagonists prevented LID in animal model of PD. However, the mechanism in which adenosine A2AR blockade alleviates the symptoms of LID has not been fully clarified. Here, we determined to knock out (KO) the gene of A2AR and explored the possible underlying mechanisms implicated in development of LID in a mouse model of PD. A2AR gene KO mice were unilaterally injected into the striatum with 6-hydroxydopamine (6-OHDA) in order to damage dopamine neurons on one side of the brain. 6-OHDA-lesioned mice were then injected once daily for 21 days with l-DOPA. Abnormal involuntary movements (AIMs) were evaluated on days 3, 8, 13, and 18 after l-DOPA administration, and real-time polymerase chain reaction and immunohistochemistry for glutamic acid decarboxylase (GAD) 65 and GAD67 were performed. We found that A2AR gene KO was effective in reducing AIM scores and accompanied with decrease of striatal GAD67, rather than GAD65. These results demonstrated that the possible mechanism involved in alleviation of AIM symptoms by A2AR gene KO might be through reducing the expression of striatal GAD67.
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Affiliation(s)
- Su-Bing Yin
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
| | - Xiao-Guang Zhang
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
| | - Shuang Chen
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
| | - Wen-Ting Yang
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
| | - Xia-Wei Zheng
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
| | - Guo-Qing Zheng
- Department of Neurology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
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11
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Minic Z, O'Leary DS, Scislo TJ. NTS adenosine A2a receptors inhibit the cardiopulmonary chemoreflex control of regional sympathetic outputs via a GABAergic mechanism. Am J Physiol Heart Circ Physiol 2015; 309:H185-97. [PMID: 25910812 DOI: 10.1152/ajpheart.00838.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 04/21/2015] [Indexed: 11/22/2022]
Abstract
Adenosine is a powerful central neuromodulator acting via opposing A1 (inhibitor) and A2a (activator) receptors. However, in the nucleus of the solitary tract (NTS), both adenosine receptor subtypes attenuate cardiopulmonary chemoreflex (CCR) sympathoinhibition of renal, adrenal, and lumbar sympathetic nerve activity and attenuate reflex decreases in arterial pressure and heart rate. Adenosine A1 receptors inhibit glutamatergic transmission in the CCR pathway, whereas adenosine A2a receptors most likely facilitate release of an unknown inhibitory neurotransmitter, which, in turn, inhibits the CCR. We hypothesized that adenosine A2a receptors inhibit the CCR via facilitation of GABA release in the NTS. In urethane-chloralose-anesthetized rats (n = 51), we compared regional sympathetic responses evoked by stimulation of the CCR with right atrial injections of the 5-HT3 receptor agonist phenylbiguanide (1-8 μg/kg) before and after selective stimulation of NTS adenosine A2a receptors [microinjections into the NTS of CGS-21680 (20 pmol/50 nl)] preceded by blockade of GABAA or GABAB receptors in the NTS [bicuculline (10 pmol/100 nl) or SCH-50911 (1 nmol/100 nl)]. Blockade of GABAA receptors virtually abolished adenosine A2a receptor-mediated inhibition of the CCR. GABAB receptors had much weaker but significant effects. These effects were similar for the different sympathetic outputs. We conclude that stimulation of NTS adenosine A2a receptors inhibits CCR-evoked hemodynamic and regional sympathetic reflex responses via a GABA-ergic mechanism.
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Affiliation(s)
- Zeljka Minic
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Donal S O'Leary
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
| | - Tadeusz J Scislo
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, Michigan
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The Story of Istradefylline—The First Approved A2A Antagonist for the Treatment of Parkinson’s Disease. CURRENT TOPICS IN NEUROTOXICITY 2015. [DOI: 10.1007/978-3-319-20273-0_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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13
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Silkis IG. The reasons for the preferable use of A2A receptor antagonists for improvement of locomotor activity and learning. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414040072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Morales-Figueroa GE, Márquez-Gómez R, González-Pantoja R, Escamilla-Sánchez J, Arias-Montaño JA. Histamine H3 receptor activation counteracts adenosine A2A receptor-mediated enhancement of depolarization-evoked [3H]-GABA release from rat globus pallidus synaptosomes. ACS Chem Neurosci 2014; 5:637-45. [PMID: 24884070 DOI: 10.1021/cn500001m] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
High levels of histamine H3 receptors (H3Rs) are found in the globus pallidus (GP), a neuronal nucleus in the basal ganglia involved in the control of motor behavior. By using rat GP isolated nerve terminals (synaptosomes), we studied whether H3R activation modified the previously reported enhancing action of adenosine A2A receptor (A2AR) stimulation on depolarization-evoked [(3)H]-GABA release. At 3 and 10 nM, the A2AR agonist CGS-21680 enhanced [(3)H]-GABA release induced by high K(+) (20 mM) and the effect of 3 nM CGS-21680 was prevented by the A2AR antagonist ZM-241385 (100 nM). The presence of presynaptic H3Rs was confirmed by the specific binding of N-α-[methyl-(3)H]-histamine to membranes from GP synaptosomes (maximum binding, Bmax, 1327 ± 79 fmol/mg protein; dissociation constant, Kd, 0.74 nM), which was inhibited by the H3R ligands immepip, clobenpropit, and A-331440 (inhibition constants, Ki, 0.28, 8.53, and 316 nM, respectively). Perfusion of synaptosomes with the H3R agonist immepip (100 nM) had no effect on K(+)-evoked [(3)H]-GABA release, but inhibited the stimulatory action of A2AR activation. In turn, the effect of immepip was blocked by the H3R antagonist clobenpropit, which had no significant effect of its own on K(+)-induced [(3)H]-GABA release. These data indicate that H3R activation selectively counteracts the facilitatory action of A2AR stimulation on GABA release from striato-pallidal projections.
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Affiliation(s)
- Guadalupe-Elide Morales-Figueroa
- Departamento de Fisiología,
Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico
Nacional 2508, Zacatenco, 07360 México, D.F., México
| | - Ricardo Márquez-Gómez
- Departamento de Fisiología,
Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico
Nacional 2508, Zacatenco, 07360 México, D.F., México
| | - Raúl González-Pantoja
- Departamento de Fisiología,
Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico
Nacional 2508, Zacatenco, 07360 México, D.F., México
| | - Juan Escamilla-Sánchez
- Departamento de Fisiología,
Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico
Nacional 2508, Zacatenco, 07360 México, D.F., México
| | - José-Antonio Arias-Montaño
- Departamento de Fisiología,
Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico
Nacional 2508, Zacatenco, 07360 México, D.F., México
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15
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Jenner P. An Overview of Adenosine A2A Receptor Antagonists in Parkinson's Disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 119:71-86. [DOI: 10.1016/b978-0-12-801022-8.00003-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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16
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Mode of Action of Adenosine A2A Receptor Antagonists as Symptomatic Treatment for Parkinson's Disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 119:87-116. [DOI: 10.1016/b978-0-12-801022-8.00004-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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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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18
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Tebano MT, Martire A, Popoli P. Adenosine A(2A)-cannabinoid CB(1) receptor interaction: an integrative mechanism in striatal glutamatergic neurotransmission. Brain Res 2012; 1476:108-18. [PMID: 22565012 DOI: 10.1016/j.brainres.2012.04.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 12/12/2022]
Abstract
The striatum is a subcortical area involved in sensorimotor, cognitive and emotional processes. Adenosine A(2A) receptors (A(2A)Rs) are highly expressed in the striatum, and their ability to establish functional and molecular interactions with many other receptors attributes to a pivotal role in the modulation and integration of striatal neurotransmission. This review will focus on the interaction between A(2A)Rs and cannabinoid CB(1) receptors (CB(1)Rs), taking it as a paradigmatic example of synaptic integration. Indeed, A(2A)Rs can exert an opposite (permissive vs. inhibitory) influence on CB1-dependent synaptic effect. These apparently irreconcilable functions could depend on a different role of pre- vs. postsynaptic A(2A)Rs, on their interaction with other receptors (namely adenosine A(1), metabotropic glutamate 5 and dopamine D2 receptors), and on whether A(2A)Rs form or not heteromers with CB(1)Rs. Besides providing a good example of the intricate pattern of events taking place in striatal synapses, the A(2A)/CB(1)R interaction proves very informative to understand the physiology of the basal ganglia and the mechanisms of related diseases. This article is part of a Special Issue entitled: Brain Integration.
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Affiliation(s)
- Maria Teresa Tebano
- Section of Central Nervous System Pharmacology, Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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19
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Constitutive activity of the A2A adenosine receptor and compartmentalised cyclic AMP signalling fine-tune noradrenaline release. Purinergic Signal 2012; 8:677-92. [PMID: 22476939 DOI: 10.1007/s11302-012-9298-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 03/09/2012] [Indexed: 10/28/2022] Open
Abstract
Neuroblastoma SH-SY5Y (SH) cells endogenously express A(2A) adenosine receptors and can be differentiated into a sympathetic neuronal phenotype, capable of depolarisation-dependent noradrenaline release. Using differentiated SH culture, we here explored the link between A(2A)-receptor signalling and neurotransmitter release. In response to the receptor agonist CGS21680, the cells produced cyclic AMP (cAMP), and when depolarised, they released increased amounts of noradrenaline. An A(2A)-receptor antagonist, XAC, as well as an inhibitor of cAMP-dependent protein kinase A (PKA), H89, depressed agonist-dependent release. In the presence of XAC or H89, noradrenaline release was found to be below basal values. This suggested that release facilitation also owes to constitutive receptor activity. We demonstrate that even in the absence of an agonist, the native A(2A)-receptor stimulated cAMP production, leading to the activation of PKA and enhanced noradrenaline release. Ancillary, non-cAMP-dependent effects of the receptor (i.e. phosphorylation of CREB, of Rabphilin3A) were refractory to constitutive activation. PKA-dependent facilitation of noradrenaline release was recapitulated with membrane-permeable 8-Br-cAMP; in addition to facilitation, 8-Br-cAMP caused marked inhibition of release, an effect not observed upon receptor activation. Inhibition by receptor-independent cAMP was likely due to suppression of voltage-dependent calcium current (VDCC) and increased activity of Src-family kinases. Receptor-mediated release facilitation was reproduced in the presence of tetrodotoxin (blocking action potentials); hence, the signalling occurred at the active zone comprising release sites. Our findings thus support (1) presynaptic localisation of the A(2A)-receptor and (2) suggest that compartmentalised pathways transmit cAMP signalling in order to facilitate depolarisation-dependent neurotransmitter release.
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20
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Abstract
Adenosine A(2A) receptor antagonists are psychomotor stimulants that also hold therapeutic promise for movement disorders. However, the molecular mechanisms underlying their stimulant properties are not well understood. Here, we show that the robust increase in locomotor activity induced by an A(2A) antagonist in vivo is greatly attenuated by antagonizing cannabinoid CB(1) receptor signaling or by administration to CB(1)(-/-) mice. To determine the locus of increased endocannabinoid signaling, we measured the amount of anandamide [AEA (N-arachidonoylethanolamine)] and 2-arachidonoylglycerol (2-AG) in brain tissue from striatum and cortex. We find that 2-AG is selectively increased in striatum after acute blockade of A(2A) receptors, which are highly expressed by striatal indirect-pathway medium spiny neurons (MSNs). Using targeted whole-cell recordings from direct- and indirect-pathway MSNs, we demonstrate that A(2A) receptor antagonists potentiate 2-AG release and induction of long-term depression at indirect-pathway MSNs, but not direct-pathway MSNs. Together, these data outline a molecular mechanism by which A(2A) antagonists reduce excitatory synaptic drive on the indirect pathway through CB(1) receptor signaling, thus leading to increased psychomotor activation.
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21
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Morelli M, Carta AR, Kachroo A, Schwarzschild MA. Pathophysiological roles for purines: adenosine, caffeine and urate. PROGRESS IN BRAIN RESEARCH 2010; 183:183-208. [PMID: 20696321 PMCID: PMC3102301 DOI: 10.1016/s0079-6123(10)83010-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The motor symptoms of Parkinson's disease (PD) are primarily due to the degeneration of the dopaminergic neurons in the nigrostriatal pathway. However, several other brain areas and neurotransmitters other than dopamine such as noradrenaline, 5-hydroxytryptamine and acetylcholine are affected in the disease. Moreover, adenosine because of the extensive interaction of its receptors with the dopaminergic system has been implicated in the pathophysiology of the disease. Based on the involvement of these non-dopaminergic neurotransmitters in PD and the sometimes severe adverse effects that limit the mainstay use of dopamine-based anti-parkinsonian treatments, recent assessments have called for a broadening of therapeutic options beyond the traditional dopaminergic drug arsenal. In this review we describe the interactions between dopamine and adenosine receptors that underpin the pre-clinical and clinical rationale for pursuing adenosine A(2A) receptor antagonists as symptomatic and potentially neuroprotective treatment of PD. The review will pay particular attention to recent results regarding specific A(2A) receptor-receptor interactions and recent findings identifying urate, the end product of purine metabolism, as a novel prognostic biomarker and candidate neuroprotectant in PD.
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Affiliation(s)
- Micaela Morelli
- Department of Toxicology, University of Cagliari, Cagliari, Italy.
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22
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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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23
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Brooks DJ, Doder M, Osman S, Luthra SK, Hirani E, Hume S, Kase H, Kilborn J, Martindill S, Mori A. Positron emission tomography analysis of [11C]KW-6002 binding to human and rat adenosine A2A receptors in the brain. Synapse 2008; 62:671-81. [PMID: 18566974 DOI: 10.1002/syn.20539] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Adenosine A(2A) receptors are found on striatal neurones projecting to the external pallidum. KW-6002 (istradefylline) is a potent and selective antagonist for the adenosine A(2A) receptors in the CNS and acts to inhibit the excessive activity of this pathway in the MPTP marmoset model of PD, thus relieving parkinsonism. The objectives of this study were to investigate the regional binding of the novel positron emission tomography tracer [(11)C]KW-6002 in the healthy human brain and the rat brain, along with receptor occupancy by cold KW-6002 at varying doses in human. The highest [(11)C]KW-6002 uptake in the rat brain was seen in striatum and lower levels in cortex and cerebellum. Brain [(11)C]KW-6002 uptake was well characterized in humans by a two-tissue compartmental model with a blood volume term, and the ED(50) of cold KW-6002 was 0.5 mg in the striatum. Over 90% receptor occupancy was achieved with daily oral doses of greater than 5 mg. In humans, blockable binding was present in all gray matter structures including the cerebellum, which has not been reported to express A(2A) receptors. MRS 1745, an A(2B) receptor selective antagonist, had no effect on the cerebellar binding of [(11)C]KW-6002 in rats, suggesting that this blockable signal is unlikely to result from an affinity for adenosine A(2B) receptors.
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Affiliation(s)
- D J Brooks
- MRC Clinical Sciences Centre and Division of Neuroscience, Faculty of Medicine, Imperial College, London, United Kingdom
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24
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Lopez S, Turle-Lorenzo N, Johnston TH, Brotchie JM, Schann S, Neuville P, Amalric M. Functional interaction between adenosine A2A and group III metabotropic glutamate receptors to reduce parkinsonian symptoms in rats. Neuropharmacology 2008; 55:483-90. [DOI: 10.1016/j.neuropharm.2008.06.038] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2008] [Revised: 06/19/2008] [Accepted: 06/20/2008] [Indexed: 10/21/2022]
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25
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Cunha RA, Ferré S, Vaugeois JM, Chen JF. Potential therapeutic interest of adenosine A2A receptors in psychiatric disorders. Curr Pharm Des 2008; 14:1512-24. [PMID: 18537674 DOI: 10.2174/138161208784480090] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The interest on targeting adenosine A(2A) receptors in the realm of psychiatric diseases first arose based on their tight physical and functional interaction with dopamine D(2) receptors. However, the role of central A(2A) receptors is now viewed as much broader than just controlling D(2) receptor function. Thus, there is currently a major interest in the ability of A(2A) receptors to control synaptic plasticity at glutamatergic synapses. This is due to a combined ability of A(2A) receptors to facilitate the release of glutamate and the activation of NMDA receptors. Therefore, A(2A) receptors are now conceived as a normalizing device promoting adequate adaptive responses in neuronal circuits, a role similar to that fulfilled, in essence, by dopamine. This makes A(2A) receptors particularly attractive targets to manage psychiatric disorders since adenosine may act as go-between glutamate and dopamine, two of the key players in mood processing. Furthermore, A(2A) receptors also control glia function and brain metabolic adaptation, two other emerging mechanisms to understand abnormal processing of mood, and A(2A) receptors are important players in controlling the demise of neurodegeneration, considered an amplificatory loop in psychiatric disorders. Current data only provide an indirect confirmation of this putative role of A(2A) receptors, based on the effects of caffeine (an antagonist of both A(1) and A(2A) receptors) in psychiatric disorders. However, the introduction of A(2A) receptors antagonists in clinics as anti-parkinsonian agents is hoped to bolster our knowledge on the role of A(2A) receptors in mood disorders in the near future.
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Affiliation(s)
- Rodrigo A Cunha
- Center for Neuroscience of Coimbra, Institute of Biochemistry, Faculty of Medicine, University of Coimbra, Portugal.
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26
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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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27
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Shindou T, Arbuthnott GW, Wickens JR. Actions of adenosine A 2A receptors on synaptic connections of spiny projection neurons in the neostriatal inhibitory network. J Neurophysiol 2008; 99:1884-9. [PMID: 18272872 DOI: 10.1152/jn.01259.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is growing evidence that adenosine plays a crucial role in basal ganglia function, particularly in the modulation of voluntary movement. An adenosine-based treatment for Parkinson's disease shows promise in recent clinical studies. Adenosine A(2A) receptors, the receptors involved in this treatment, are highly expressed in the neostriatum. Previous studies have suggested opposing actions of these receptors on synaptic transmission at striatal and pallidal terminals of the same spiny projection neurons, but the cells of origin of the intrastriatal terminals mediating these actions have not been identified. We used dual whole cell recordings to record simultaneously from pairs of striatal cells; this enabled definitive identification of the presynaptic and postsynaptic cells mediating the effects of A(2A) receptors. We found that A(2A) receptors facilitate GABAergic synaptic transmission by intrastriatal collaterals of the spiny projection neurons, consistent with their previously reported actions on synaptic transmission at pallidal terminals. This neuromodulatory action on lateral inhibition in the striatum may underlie, in part, the therapeutic efficacy of adenosine-based treatments for Parkinson's disease.
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Affiliation(s)
- Tomomi Shindou
- Department of Anatomy and Structural Biology, University of Otago, Dunedin, New Zealand
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28
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Schiffmann SN, Fisone G, Moresco R, Cunha RA, Ferré S. Adenosine A2A receptors and basal ganglia physiology. Prog Neurobiol 2007; 83:277-92. [PMID: 17646043 PMCID: PMC2148496 DOI: 10.1016/j.pneurobio.2007.05.001] [Citation(s) in RCA: 275] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2006] [Revised: 03/30/2007] [Accepted: 05/29/2007] [Indexed: 12/20/2022]
Abstract
Adenosine A2A receptors are highly enriched in the basal ganglia system. They are predominantly expressed in enkephalin-expressing GABAergic striatopallidal neurons and therefore are highly relevant to the function of the indirect efferent pathway of the basal ganglia system. In these GABAergic enkephalinergic neurons, the A2A receptor tightly interacts structurally and functionally with the dopamine D2 receptor. Both by forming receptor heteromers and by targeting common intracellular signaling cascades, A2A and D2 receptors exhibit reciprocal antagonistic interactions that are central to the function of the indirect pathway and hence to basal ganglia control of movement, motor learning, motivation and reward. Consequently, this A2A/D2 receptors antagonistic interaction is also central to basal ganglia dysfunction in Parkinson's disease. However, recent evidence demonstrates that, in addition to this post-synaptic site of action, striatal A2A receptors are also expressed and have physiological relevance on pre-synaptic glutamatergic terminals of the cortico-limbic-striatal and thalamo-striatal pathways, where they form heteromeric receptor complexes with adenosine A1 receptors. Therefore, A2A receptors play an important fine-tuning role, boosting the efficiency of glutamatergic information flow in the indirect pathway by exerting control, either pre- and/or post-synaptically, over other key modulators of glutamatergic synapses, including D2 receptors, group I metabotropic mGlu5 glutamate receptors and cannabinoid CB1 receptors, and by triggering the cAMP-protein kinase A signaling cascade.
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Affiliation(s)
- S N Schiffmann
- Laboratory of Neurophysiology, Université Libre de Bruxelles, Campus Erasme, 808 route de Lennik, CP601, 1070 Brussels, Belgium.
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29
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Abstract
The external segment of the pallidum (GP(e)) is a relatively large nucleus located caudomedial to the neostriatum (Str). The GP(e) receives major inputs from two major basal ganglia input nuclei, the Str and the subthalamic nucleus (STN), and sends its output to many basal ganglia nuclei including the STN, the Str, the internal pallidal segment (GP(i)), and the substantia nigra (SN). Thus, the GPe can be placed at the center of the basal ganglia connection diagram (Fig. 1(A)). From the viewpoint that emphasizes the direct and indirect pathways of the basal ganglia, the GP(e) is a component of the indirect pathway that relays Str inputs to the STN. The indirect pathway can be traced in Fig. 1(A), although it comprises only a part of multiple indirect pathways. This chapter begins with a brief description of the anatomical organization of the GP(e) followed by physiological and pharmacological characterizations of GABAergic responses in the GP(e).
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Affiliation(s)
- Hitoshi Kita
- Department of Anatomy and Neurobiology, The University of Tennessee Memphis, 855 Monroe Avenue, Memphis, TN 38163, USA.
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30
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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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31
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Ochi M, Shiozaki S, Kase H. Adenosine A2A receptor-mediated modulation of GABA and glutamate release in the output regions of the basal ganglia in a rodent model of Parkinson's disease. Neuroscience 2004; 127:223-31. [PMID: 15219684 DOI: 10.1016/j.neuroscience.2004.04.050] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2004] [Indexed: 11/21/2022]
Abstract
A target neuron of adenosine A(2A) receptor antagonists to exert anti-parkinsonian activities has been currently identified to be, at least in part, striatopallidal medium spiny neurons (MSNs). In the present study, we determine whether A(2A) receptor-mediated modulation is associated with changes in the release of GABA and glutamate in the substantia nigra pars reticulata (SNr), an output structure of the whole basal ganglia network, using in vivo microdialysis in a rat Parkinson's disease (PD) model. In 6-hydroxydopamine (OHDA)-lesioned rats compared with normal rats, basal extracellular GABA levels in the SNr show no change, whereas basal glutamate levels are significantly increased. Oral administration of the A(2A) receptor-selective antagonist (E-1,3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1-H-purine-2,6-dion (KW-6002) to 6-OHDA-lesioned rats at 1 mg/kg caused a marked and sustained increase of GABA and glutamate levels in the SNr. The increase of nigral glutamate by KW-6002 was abolished by a kainic acid-induced lesion of the globus pallidus (GP) or subthalamic nucleus (STN) in 6-OHDA-lesioned rats, whereas the increase of nigral GABA was completely blocked by the GP-lesion but only partially blocked by the STN-lesion. These results indicate that changes in neurotransmitter release in the SNr brought about by KW-6002 are largely attributable to blockade of A(2A) receptor-mediated modulation of striatopallidal MSNs. Thus, these actions of KW-6002 on striatopallidal MSNs may be the main mechanism for ameliorating PD by A(2A) antagonists.
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Affiliation(s)
- M Ochi
- Pharmaceutical Research Institute, Kyowa Hakko Kogyo Co., Ltd, Nagaizumi, Sunto, Shizuoka 411-8731, Japan
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