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Murakami Y, Imamura Y, Kasahara Y, Yoshida C, Momono Y, Fang K, Sakai D, Konishi Y, Nishiyama T. Maternal Inflammation with Elevated Kynurenine Metabolites Is Related to the Risk of Abnormal Brain Development and Behavioral Changes in Autism Spectrum Disorder. Cells 2023; 12:cells12071087. [PMID: 37048160 PMCID: PMC10093447 DOI: 10.3390/cells12071087] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/27/2023] [Accepted: 03/31/2023] [Indexed: 04/14/2023] Open
Abstract
Several studies show that genetic and environmental factors contribute to the onset and progression of neurodevelopmental disorders. Maternal immune activation (MIA) during gestation is considered one of the major environmental factors driving this process. The kynurenine pathway (KP) is a major route of the essential amino acid L-tryptophan (Trp) catabolism in mammalian cells. Activation of the KP following neuro-inflammation can generate various endogenous neuroactive metabolites that may impact brain functions and behaviors. Additionally, neurotoxic metabolites and excitotoxicity cause long-term changes in the trophic support, glutamatergic system, and synaptic function following KP activation. Therefore, investigating the role of KP metabolites during neurodevelopment will likely promote further understanding of additional pathophysiology of neurodevelopmental disorders, including autism spectrum disorder (ASD). In this review, we describe the changes in KP metabolism in the brain during pregnancy and represent how maternal inflammation and genetic factors influence the KP during development. We overview the patients with ASD clinical data and animal models designed to verify the role of perinatal KP elevation in long-lasting biochemical, neuropathological, and behavioral deficits later in life. Our review will help shed light on new therapeutic strategies and interventions targeting the KP for neurodevelopmental disorders.
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Affiliation(s)
- Yuki Murakami
- Department of Hygiene and Public Health, Kansai Medical University, Hirakata 573-1010, Japan
| | - Yukio Imamura
- Department of Architecture and Architectual Systems Engineering, Graduate School of Engineering, Kyoto University, Kyoto 615-8530, Japan
- Department of Traumatology and Acute Critical Medicine, Graduate School of Medicine/Faculty of Medicine, Osaka University, Suita 565-0871, Japan
| | - Yoshiyuki Kasahara
- Department of Maternal and Fetal Therapeutics, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Chihiro Yoshida
- Department of Maternal and Fetal Therapeutics, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Yuta Momono
- Department of Maternal and Fetal Therapeutics, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Ke Fang
- Department of Hygiene and Public Health, Kansai Medical University, Hirakata 573-1010, Japan
| | - Daisuke Sakai
- Department of Biology, Kanazawa Medical University, Kanazawa 920-0293, Japan
| | - Yukuo Konishi
- Center for Baby Science, Doshisha University, Kyotanabe 619-0225, Japan
- Healthcare and Medical Data Multi-Level Integration Platform Group, RIKEN Medical Sciences Innovation Hub Program, Yokohama 230-0045, Japan
| | - Toshimasa Nishiyama
- Department of Hygiene and Public Health, Kansai Medical University, Hirakata 573-1010, Japan
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Martos D, Tuka B, Tanaka M, Vécsei L, Telegdy G. Memory Enhancement with Kynurenic Acid and Its Mechanisms in Neurotransmission. Biomedicines 2022; 10:biomedicines10040849. [PMID: 35453599 PMCID: PMC9027307 DOI: 10.3390/biomedicines10040849] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 03/28/2022] [Accepted: 04/02/2022] [Indexed: 02/04/2023] Open
Abstract
Kynurenic acid (KYNA) is an endogenous tryptophan (Trp) metabolite known to possess neuroprotective property. KYNA plays critical roles in nociception, neurodegeneration, and neuroinflammation. A lower level of KYNA is observed in patients with neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases or psychiatric disorders such as depression and autism spectrum disorders, whereas a higher level of KYNA is associated with the pathogenesis of schizophrenia. Little is known about the optimal concentration for neuroprotection and the threshold for neurotoxicity. In this study the effects of KYNA on memory functions were investigated by passive avoidance test in mice. Six different doses of KYNA were administered intracerebroventricularly to previously trained CFLP mice and they were observed for 24 h. High doses of KYNA (i.e., 20–40 μg/2 μL) significantly decreased the avoidance latency, whereas a low dose of KYNA (0.5 μg/2 μL) significantly elevated it compared with controls, suggesting that the low dose of KYNA enhanced memory function. Furthermore, six different receptor blockers were applied to reveal the mechanisms underlying the memory enhancement induced by KYNA. The series of tests revealed the possible involvement of the serotonergic, dopaminergic, α and β adrenergic, and opiate systems in the nootropic effect. This study confirmed that a low dose of KYNA improved a memory component of cognitive domain, which was mediated by, at least in part, four systems of neurotransmission in an animal model of learning and memory.
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Affiliation(s)
- Diána Martos
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
| | - Bernadett Tuka
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
| | - Masaru Tanaka
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
| | - László Vécsei
- MTA-SZTE Neuroscience Research Group, Hungarian Academy of Sciences, University of Szeged (MTA-SZTE), Semmelweis u. 6, H-6725 Szeged, Hungary; (D.M.); (B.T.); (M.T.)
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary
- Correspondence: ; Tel.: +36-62-342-361
| | - Gyula Telegdy
- Department of Pathophysiology, Albert Szent-Györgyi Medical School, University of Szeged, Semmelweis u. 5, H-6725 Szeged, Hungary;
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Bai MY, Lovejoy DB, Guillemin GJ, Kozak R, Stone TW, Koola MM. Galantamine-Memantine Combination and Kynurenine Pathway Enzyme Inhibitors in the Treatment of Neuropsychiatric Disorders. Complex Psychiatry 2021; 7:19-33. [PMID: 35141700 PMCID: PMC8443947 DOI: 10.1159/000515066] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 02/04/2021] [Indexed: 12/25/2022] Open
Abstract
The kynurenine pathway (KP) is a major route for L-tryptophan (L-TRP) metabolism, yielding a variety of bioactive compounds including kynurenic acid (KYNA), 3-hydroxykynurenine (3-HK), quinolinic acid (QUIN), and picolinic acid (PIC). These tryptophan catabolites are involved in the pathogenesis of many neuropsychiatric disorders, particularly when the KP becomes dysregulated. Accordingly, the enzymes that regulate the KP such as indoleamine 2,3-dioxygenase (IDO)/tryptophan 2,3-dioxygenase, kynurenine aminotransferases (KATs), and kynurenine 3-monooxygenase (KMO) represent potential drug targets as enzymatic inhibition can favorably rebalance KP metabolite concentrations. In addition, the galantamine-memantine combination, through its modulatory effects at the alpha7 nicotinic acetylcholine receptors and N-methyl-D-aspartate receptors, may counteract the effects of KYNA. The aim of this review is to highlight the effectiveness of IDO-1, KAT II, and KMO inhibitors, as well as the galantamine-memantine combination in the modulation of different KP metabolites. KAT II inhibitors are capable of decreasing the KYNA levels in the rat brain by a maximum of 80%. KMO inhibitors effectively reduce the central nervous system (CNS) levels of 3-HK, while markedly boosting the brain concentration of KYNA. Emerging data suggest that the galantamine-memantine combination also lowers L-TRP, kynurenine, KYNA, and PIC levels in humans. Presently, there are only 2 pathophysiological mechanisms (cholinergic and glutamatergic) that are FDA approved for the treatment of cognitive dysfunction for which purpose the galantamine-memantine combination has been designed for clinical use against Alzheimer's disease. The alpha7 nicotinic-NMDA hypothesis targeted by the galantamine-memantine combination has been implicated in the pathophysiology of various CNS diseases. Similarly, KYNA is well capable of modulating the neuropathophysiology of these disorders. This is known as the KYNA-centric hypothesis, which may be implicated in the management of certain neuropsychiatric conditions. In line with this hypothesis, KYNA may be considered as the "conductor of the orchestra" for the major pathophysiological mechanisms underlying CNS disorders. Therefore, there is great opportunity to further explore and compare the biological effects of these therapeutic modalities in animal models with a special focus on their effects on KP metabolites in the CNS and with the ultimate goal of progressing to clinical trials for many neuropsychiatric diseases.
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Affiliation(s)
- Michael Y. Bai
- Department of Biomedical Sciences, Neuroinflammation Group, Macquarie University Centre for Motor Neuron Disease Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - David B. Lovejoy
- Department of Biomedical Sciences, Neuroinflammation Group, Macquarie University Centre for Motor Neuron Disease Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Gilles J. Guillemin
- Department of Biomedical Sciences, Neuroinflammation Group, Macquarie University Centre for Motor Neuron Disease Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Rouba Kozak
- Neuroscience Drug Discovery Unit, Takeda Pharmaceuticals International Co, Cambridge, Massachusetts, USA
| | - Trevor W. Stone
- Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, United Kingdom
| | - Maju Mathew Koola
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, Stony Brook, New York, USA
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Stone TW. Relationships and Interactions between Ionotropic Glutamate Receptors and Nicotinic Receptors in the CNS. Neuroscience 2021; 468:321-365. [PMID: 34111447 DOI: 10.1016/j.neuroscience.2021.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 02/07/2023]
Abstract
Although ionotropic glutamate receptors and nicotinic receptors for acetylcholine (ACh) have usually been studied separately, they are often co-localized and functionally inter-dependent. The objective of this review is to survey the evidence for interactions between the two receptor families and the mechanisms underlying them. These include the mutual regulation of subunit expression, which change the NMDA:AMPA response balance, and the existence of multi-functional receptor complexes which make it difficult to distinguish between individual receptor sites, especially in vivo. This is followed by analysis of the functional relationships between the receptors from work on transmitter release, cellular electrophysiology and aspects of behavior where these can contribute to understanding receptor interactions. It is clear that nicotinic receptors (nAChRs) on axonal terminals directly regulate the release of glutamate and other neurotransmitters, α7-nAChRs generally promoting release. Hence, α7-nAChR responses will be prevented not only by a nicotinic antagonist, but also by compounds blocking the indirectly activated glutamate receptors. This accounts for the apparent anticholinergic activity of some glutamate antagonists, including the endogenous antagonist kynurenic acid. The activation of presynaptic nAChRs is by the ambient levels of ACh released from pre-terminal synapses, varicosities and glial cells, acting as a 'volume neurotransmitter' on synaptic and extrasynaptic sites. In addition, ACh and glutamate are released as CNS co-transmitters, including 'cholinergic' synapses onto spinal Renshaw cells. It is concluded that ACh should be viewed primarily as a modulator of glutamatergic neurotransmission by regulating the release of glutamate presynaptically, and the location, subunit composition, subtype balance and sensitivity of glutamate receptors, and not primarily as a classical fast neurotransmitter. These conclusions and caveats should aid clarification of the sites of action of glutamate and nicotinic receptor ligands in the search for new centrally-acting drugs.
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Affiliation(s)
- Trevor W Stone
- The Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK; Institute of Neuroscience, University of Glasgow, G12 8QQ, UK.
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5
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Duan J, Xie P. The potential for metabolomics in the study and treatment of major depressive disorder and related conditions. Expert Rev Proteomics 2020; 17:309-322. [DOI: 10.1080/14789450.2020.1772059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Jiajia Duan
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, Chongqing Medical University, Chongqing, China
- The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The College of Laboratory Medicine, Chongqing Medical University, Chongqing, China
| | - Peng Xie
- NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, Chongqing Medical University, Chongqing, China
- The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The College of Laboratory Medicine, Chongqing Medical University, Chongqing, China
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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6
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Tarasov VV, Svistunov AA, Chubarev VN, Sologova SS, Mukhortova P, Levushkin D, Somasundaram SG, Kirkland CE, Bachurin SO, Aliev G. Alterations of Astrocytes in the Context of Schizophrenic Dementia. Front Pharmacol 2020; 10:1612. [PMID: 32116664 PMCID: PMC7020441 DOI: 10.3389/fphar.2019.01612] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/10/2019] [Indexed: 12/19/2022] Open
Abstract
The levels of the astrocyte markers (GFAP, S100B) were increased unevenly in patients with schizophrenia. Reactive astrogliosis was found in approximately 70% of patients with schizophrenia. The astrocytes play a major role in etiology and pathogenesis of schizophrenia. Astrocytes produce the components that altered in schizophrenia extracellular matrix system which are involved in inflammation, functioning of interneurons, glio-, and neurotransmitter system, especially glutamate system. Astrocytes activate the interneurons through glutamate release and ATP. Decreased expression of astrocyte glutamate transporters was observed in patients with schizophrenia. Astrocytes influence on N-methyl-d-aspartate (NMDA) receptors via D-serine, an agonist of the glycine-binding site of NMDA receptors, and kynurenic acid, an endogenous antagonist. NMDA receptors, on its turn, control the impulses of dopamine neurons. Therefore following theories of schizophrenia are proposed. They are a) activation of astrocytes for neuroinflammation, b) glutamate and dopamine theory, as astrocyte products control the activity of NMDA receptors, which influence on the dopamine neurons.
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Affiliation(s)
- Vadim V Tarasov
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Andrey A Svistunov
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Vladimir N Chubarev
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Susanna S Sologova
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Polina Mukhortova
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Dmitrii Levushkin
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Siva G Somasundaram
- Department of Biological Sciences, Salem University, Salem, WV, United States
| | - Cecil E Kirkland
- Department of Biological Sciences, Salem University, Salem, WV, United States
| | - Sergey O Bachurin
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, Russia
| | - Gjumrakch Aliev
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia.,Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, Russia.,Federal State Budgetary Institution, Research Institute of Human Morphology, Russian Federation, Moscow, Russia.,GALLY International Research Institute, San Antonio, TX, United States
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7
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Xu K, He Y, Chen X, Tian Y, Cheng K, Zhang L, Wang Y, Yang D, Wang H, Wu Z, Li Y, Lan T, Dong Z, Xie P. Validation of the targeted metabolomic pathway in the hippocampus and comparative analysis with the prefrontal cortex of social defeat model mice. J Neurochem 2019; 149:799-810. [PMID: 30520040 DOI: 10.1111/jnc.14641] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/22/2018] [Accepted: 11/28/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Ke Xu
- Department of Neurology Yongchuan Hospital of Chongqing Medical University Chongqing China
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Yong He
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Xi Chen
- Department of Neurology Yongchuan Hospital of Chongqing Medical University Chongqing China
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Yu Tian
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
- Department of Neurology the First Affiliated Hospital of Chongqing Medical University ChongqingChina
| | - Ke Cheng
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Lu Zhang
- Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders Children's Hospital of Chongqing Medical University Chongqing China
- Ministry of Education Key Laboratory of Child Development and Disorders Children's Hospital of Chongqing Medical University Chongqing China
| | - Yue Wang
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Deyu Yang
- Department of Neurology Yongchuan Hospital of Chongqing Medical University Chongqing China
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Haiyang Wang
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Zhonghao Wu
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Yan Li
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Tianlan Lan
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
| | - Zhifang Dong
- Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders Children's Hospital of Chongqing Medical University Chongqing China
- Ministry of Education Key Laboratory of Child Development and Disorders Children's Hospital of Chongqing Medical University Chongqing China
| | - Peng Xie
- Department of Neurology Yongchuan Hospital of Chongqing Medical University Chongqing China
- Institute of Neuroscience and Collaborative Innovation Center for Brain Science Chongqing Medical University Chongqing China
- Chongqing Key Laboratory of Neurobiology Chongqing China
- Department of Neurology the First Affiliated Hospital of Chongqing Medical University ChongqingChina
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8
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Mackenzie AE, Milligan G. The emerging pharmacology and function of GPR35 in the nervous system. Neuropharmacology 2017; 113:661-671. [DOI: 10.1016/j.neuropharm.2015.07.035] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 07/20/2015] [Accepted: 07/27/2015] [Indexed: 02/07/2023]
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9
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Bertrand D, Lee CHL, Flood D, Marger F, Donnelly-Roberts D. Therapeutic Potential of α7 Nicotinic Acetylcholine Receptors. Pharmacol Rev 2015; 67:1025-73. [DOI: 10.1124/pr.113.008581] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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10
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Forrest CM, McNair K, Pisar M, Khalil OS, Darlington LG, Stone TW. Altered hippocampal plasticity by prenatal kynurenine administration, kynurenine-3-monoxygenase (KMO) deletion or galantamine. Neuroscience 2015; 310:91-105. [PMID: 26365611 PMCID: PMC4642643 DOI: 10.1016/j.neuroscience.2015.09.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/11/2015] [Accepted: 09/07/2015] [Indexed: 11/16/2022]
Abstract
Glutamate receptors sensitive to N-methyl-D-aspartate (NMDA) are involved in embryonic brain development but their activity may be modulated by the kynurenine pathway of tryptophan metabolism which includes an agonist (quinolinic acid) and an antagonist (kynurenic acid) at these receptors. Our previous work has shown that prenatal inhibition of the pathway produces abnormalities of brain development. In the present study kynurenine and probenecid (both 100mg/kg, doses known to increase kynurenic acid levels in the brain) were administered to female Wistar rats on embryonic days E14, E16 and E18 of gestation and the litter was allowed to develop to post-natal day P60. Western blotting revealed no changes in hippocampal expression of several proteins previously found to be altered by inhibition of the kynurenine pathway including the NMDA receptor subunits GluN1, GluN2A and GluN2B, as well as doublecortin, Proliferating Cell Nuclear Antigen (PCNA), sonic hedgehog and unco-ordinated (unc)-5H1 and 5H3. Mice lacking the enzyme kynurenine-3-monoxygenase (KMO) also showed no changes in hippocampal expression of several of these proteins or the 70-kDa and 100-kDa variants of Disrupted in Schizophrenia-1 (DISC1). Electrical excitability of pyramidal neurons in the CA1 region of hippocampal slices was unchanged, as was paired-pulse facilitation and inhibition. Long-term potentiation was decreased in the kynurenine-treated rats and in the KMO(-/-) mice, but galantamine reversed this effect in the presence of nicotinic receptor antagonists, consistent with evidence that it can potentiate glutamate at NMDA receptors. It is concluded that interference with the kynurenine pathway in utero can have lasting effects on brain function of the offspring, implying that the kynurenine pathway is involved in the regulation of early brain development.
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Affiliation(s)
- C M Forrest
- Institute of Neuroscience and Psychology, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - K McNair
- Institute of Neuroscience and Psychology, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - M Pisar
- Institute of Neuroscience and Psychology, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - O S Khalil
- Institute of Neuroscience and Psychology, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - L G Darlington
- Ashtead Hospital, The Warren, Ashtead, Surrey KT21 2SB, UK
| | - T W Stone
- Institute of Neuroscience and Psychology, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK.
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11
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Banerjee J, Banerjee Dixit A, Tripathi M, Sarkar C, Gupta YK, Chandra PS. Enhanced endogenous activation of NMDA receptors in pyramidal neurons of hippocampal tissues from patients with mesial temporal lobe epilepsy: A mechanism of hyper excitation. Epilepsy Res 2015; 117:11-6. [PMID: 26320079 DOI: 10.1016/j.eplepsyres.2015.08.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/17/2015] [Accepted: 08/08/2015] [Indexed: 11/30/2022]
Abstract
Altered excitatory synaptic transmission is one of the primary causes of seizure generation in patients with mesial temporal lobe epilepsy (MTLE). The present study is designed to delineate the contribution of glutamatergic tone under resting conditions to the hyper excitability in patients with MTLE. Resected hippocampal tissues were obtained from patients with MTLE. In these samples spontaneous excitatory postsynaptic currents (EPSCs), sensitive to NMDA receptor antagonist APV (50μM) and AMPA receptor antagonist CNQX (10μM) were recorded from pyramidal neurons at -70mV. We observed that frequency of EPSCs were 28.2% higher in slices obtained from patients with MTLE compared to that in case of non-epileptic controls. We also examined spontaneous fast current transients (CTs) recorded from these pyramidal neurons under cell-attached configuration. The frequency of CTs increased in the absence of extracellular Mg(2+) in brain slice preparations and was completely blocked by APV. We found that the frequency of CTs in pyramidal neurons were higher in case of MTLE samples compared to non-epileptic controls. This study suggests that enhanced endogenous activity of NMDA receptor contributes to excitability in pyramidal neurons of slice preparations obtained from patients with MTLE.
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Affiliation(s)
- Jyotirmoy Banerjee
- Center of Excellence for Epilepsy, National Brain Research Center, Manesar, India.
| | | | - Manjari Tripathi
- Center of Excellence for Epilepsy, National Brain Research Center, Manesar, India; Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
| | - Chitra Sarkar
- Department of Neuropathology, All India Institute of Medical Sciences, New Delhi, India.
| | - Yogendra Kumar Gupta
- Department of Pharmacology, All India Institute of Medical Sciences, New Delhi, India.
| | - P Sarat Chandra
- Center of Excellence for Epilepsy, National Brain Research Center, Manesar, India; Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
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12
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Varga D, Herédi J, Kánvási Z, Ruszka M, Kis Z, Ono E, Iwamori N, Iwamori T, Takakuwa H, Vécsei L, Toldi J, Gellért L. Systemic L-Kynurenine sulfate administration disrupts object recognition memory, alters open field behavior and decreases c-Fos immunopositivity in C57Bl/6 mice. Front Behav Neurosci 2015; 9:157. [PMID: 26136670 PMCID: PMC4468612 DOI: 10.3389/fnbeh.2015.00157] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 06/01/2015] [Indexed: 01/31/2023] Open
Abstract
L-Kynurenine (L-KYN) is a central metabolite of tryptophan degradation through the kynurenine pathway (KP). The systemic administration of L-KYN sulfate (L-KYNs) leads to a rapid elevation of the neuroactive KP metabolite kynurenic acid (KYNA). An elevated level of KYNA may have multiple effects on the synaptic transmission, resulting in complex behavioral changes, such as hypoactivity or spatial working memory deficits. These results emerged from studies that focused on rats, after low-dose L-KYNs treatment. However, in several studies neuroprotection was achieved through the administration of high-dose L-KYNs. In the present study, our aim was to investigate whether the systemic administration of a high dose of L-KYNs (300 mg/bwkg; i.p.) would produce alterations in behavioral tasks (open field or object recognition) in C57Bl/6j mice. To evaluate the changes in neuronal activity after L-KYNs treatment, in a separate group of animals we estimated c-Fos expression levels in the corresponding subcortical brain areas. The L-KYNs treatment did not affect the general ambulatory activity of C57Bl/6j mice, whereas it altered their moving patterns, elevating the movement velocity and resting time. Additionally, it seemed to increase anxiety-like behavior, as peripheral zone preference of the open field arena emerged and the rearing activity was attenuated. The treatment also completely abolished the formation of object recognition memory and resulted in decreases in the number of c-Fos-immunopositive-cells in the dorsal part of the striatum and in the CA1 pyramidal cell layer of the hippocampus. We conclude that a single exposure to L-KYNs leads to behavioral disturbances, which might be related to the altered basal c-Fos protein expression in C57Bl/6j mice.
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Affiliation(s)
- Dániel Varga
- Department of Physiology, Anatomy and Neuroscience, University of Szeged Szeged, Hungary
| | - Judit Herédi
- Department of Physiology, Anatomy and Neuroscience, University of Szeged Szeged, Hungary
| | - Zita Kánvási
- Department of Physiology, Anatomy and Neuroscience, University of Szeged Szeged, Hungary
| | - Marian Ruszka
- Department of Physiology, Anatomy and Neuroscience, University of Szeged Szeged, Hungary ; Department of Neurology, Faculty of Medicine, MTA-SZTE Neuroscience Research Group, University of Szeged Szeged, Hungary
| | - Zsolt Kis
- Department of Physiology, Anatomy and Neuroscience, University of Szeged Szeged, Hungary
| | - Etsuro Ono
- Department of Biomedicine, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan ; Center of Biomedical Research, Research Center for Human Disease Modeling, Department of Physiological Sciences, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan
| | - Naoki Iwamori
- Department of Biomedicine, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan ; Center of Biomedical Research, Research Center for Human Disease Modeling, Department of Physiological Sciences, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan
| | - Tokuko Iwamori
- Department of Biomedicine, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan ; Center of Biomedical Research, Research Center for Human Disease Modeling, Department of Physiological Sciences, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan
| | - Hiroki Takakuwa
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-Motoyama Kita, Kyoto, Japan
| | - László Vécsei
- Department of Neurology, Faculty of Medicine, MTA-SZTE Neuroscience Research Group, University of Szeged Szeged, Hungary ; Department of Neurology, University of Szeged, Hungary Szeged, Hungary
| | - József Toldi
- Department of Physiology, Anatomy and Neuroscience, University of Szeged Szeged, Hungary ; Department of Neurology, Faculty of Medicine, MTA-SZTE Neuroscience Research Group, University of Szeged Szeged, Hungary
| | - Levente Gellért
- Department of Physiology, Anatomy and Neuroscience, University of Szeged Szeged, Hungary ; Department of Neurology, Faculty of Medicine, MTA-SZTE Neuroscience Research Group, University of Szeged Szeged, Hungary
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13
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Alkondon M, Pereira EFR, Todd SW, Randall WR, Lane MV, Albuquerque EX. Functional G-protein-coupled receptor 35 is expressed by neurons in the CA1 field of the hippocampus. Biochem Pharmacol 2014; 93:506-18. [PMID: 25542997 DOI: 10.1016/j.bcp.2014.12.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 12/17/2014] [Accepted: 12/17/2014] [Indexed: 12/17/2022]
Abstract
The G-protein-coupled receptor 35 (GPR35) was de-orphanized after the discovery that kynurenic acid (KYNA), an endogenous tryptophan metabolite, acts as an agonist of this receptor. Abundant evidence supports that GPR35 exists primarily in peripheral tissues. Here, we tested the hypothesis that GPR35 exists in the hippocampus and influences the neuronal activity. Fluorescence immunohistochemical staining using an antibody anti-NeuN (a neuronal marker), an antibody anti-GFAP (a glial marker), and an antibody anti-GPR35 revealed that neurons in the stratum oriens, stratum pyramidale, and stratum radiatum of the CA1 field of the hippocampus express GPR35. To determine the presence of functional GPR35 in the neurocircuitry, we tested the effects of various GPR35 agonists on the frequency of spontaneous action potentials recorded as fast current transients (CTs) from stratum radiatum interneurons (SRIs) under cell-attached configuration in rat hippocampal slices. Bath application of the GPR35 agonists zaprinast (1-10 μM), dicumarol (50-100 μM), pamoic acid (500-1000 μM), and amlexanox (3 μM) produced a concentration- and time-dependent reduction in the frequency of CTs. Superfusion of the hippocampal slices with the GPR35 antagonist ML145 (1 μM) increased the frequency of CTs and reduced the inhibitory effect of zaprinast. Bath application of phosphodiesterase 5 inhibitor sildenafil (1 or 5 μM) was ineffective, whereas a subsequent application of zaprinast was effective in reducing the CT frequency. The present results demonstrate for the first time that functional GPR35s are expressed by CA1 neurons and suggest that these receptors can be molecular targets for controlling neuronal activity in the hippocampus.
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Affiliation(s)
- Manickavasagom Alkondon
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, 10 S. Pine Street, Suite 900, Baltimore, MD 21201, USA
| | - Edna F R Pereira
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, 10 S. Pine Street, Suite 900, Baltimore, MD 21201, USA
| | - Spencer W Todd
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, 10 S. Pine Street, Suite 900, Baltimore, MD 21201, USA
| | - William R Randall
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Malcolm V Lane
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, 10 S. Pine Street, Suite 900, Baltimore, MD 21201, USA
| | - Edson X Albuquerque
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, 10 S. Pine Street, Suite 900, Baltimore, MD 21201, USA.
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Wonodi I, McMahon RP, Krishna N, Mitchell BD, Liu J, Glassman M, Hong LE, Gold JM. Influence of kynurenine 3-monooxygenase (KMO) gene polymorphism on cognitive function in schizophrenia. Schizophr Res 2014; 160:80-7. [PMID: 25464917 PMCID: PMC4516229 DOI: 10.1016/j.schres.2014.10.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 10/09/2014] [Accepted: 10/14/2014] [Indexed: 01/04/2023]
Abstract
BACKGROUND Cognitive deficits compromise quality of life and productivity for individuals with schizophrenia and have no effective treatments. Preclinical data point to the kynurenine pathway of tryptophan metabolism as a potential target for pro-cognitive drug development. We have previously demonstrated association of a kynurenine 3-monooxygenase (KMO) gene variant with reduced KMO gene expression in postmortem schizophrenia cortex, and neurocognitive endophenotypic deficits in a clinical sample. KMO encodes kynurenine 3-monooxygenase (KMO), the rate-limiting microglial enzyme of cortical kynurenine metabolism. Aberration of the KMO gene might be the proximal cause of impaired cortical kynurenine metabolism observed in schizophrenia. However, the relationship between KMO variation and cognitive function in schizophrenia is unknown. This study examined the effects of the KMO rs2275163C>T C (risk) allele on cognitive function in schizophrenia. METHODS We examined the association of KMO polymorphisms with general neuropsychological performance and P50 gating in a sample of 150 schizophrenia and 95 healthy controls. RESULTS Consistent with our original report, the KMO rs2275163C>T C (risk) allele was associated with deficits in general neuropsychological performance, and this effect was more marked in schizophrenia compared with controls. Additionally, the C (Arg452) allele of the missense rs1053230C>T variant (KMO Arg452Cys) showed a trend effect on cognitive function. Neither variant affected P50 gating. CONCLUSIONS These data suggest that KMO variation influences a range of cognitive domains known to predict functional outcome. Extensive molecular characterization of this gene would elucidate its role in cognitive function with implications for vertical integration with basic discovery.
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Affiliation(s)
- Ikwunga Wonodi
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Robert P. McMahon
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Nithin Krishna
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Braxton D. Mitchell
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Judy Liu
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Matthew Glassman
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - L. Elliot Hong
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - James M. Gold
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
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Molas S, Gener T, Güell J, Martín M, Ballesteros-Yáñez I, Sanchez-Vives MV, Dierssen M. Hippocampal changes produced by overexpression of the human CHRNA5/A3/B4 gene cluster may underlie cognitive deficits rescued by nicotine in transgenic mice. Acta Neuropathol Commun 2014; 2:147. [PMID: 25384568 PMCID: PMC4236452 DOI: 10.1186/s40478-014-0147-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 10/02/2014] [Indexed: 11/10/2022] Open
Abstract
Addiction involves long-lasting maladaptive changes including development of disruptive drug-stimuli associations. Nicotine-induced neuroplasticity underlies the development of tobacco addiction but also, in regions such as the hippocampus, the ability of this drug to enhance cognitive capabilities. Here, we propose that the genetic locus of susceptibility to nicotine addiction, the CHRNA5/A3/B4 gene cluster, encoding the α5, α3 and β4 subunits of the nicotinic acetylcholine receptors (nAChRs), may influence nicotine-induced neuroadaptations. We have used transgenic mice overexpressing the human cluster (TgCHRNA5/A3/B4) to investigate hippocampal structure and function in genetically susceptible individuals. TgCHRNA5/A3/B4 mice presented a marked reduction in the dendrite complexity of CA1 hippocampal pyramidal neurons along with an increased dendritic spine density. In addition, TgCHRNA5/A3/B4 exhibited increased VGLUT1/VGAT ratio in the CA1 region, suggesting an excitatory/inhibitory imbalance. These hippocampal alterations were accompanied by a significant impairment in short-term novelty recognition memory. Interestingly, chronic infusion of nicotine (3.25 mg/kg/d for 7 d) was able to rescue the reduced dendritic complexity, the excitatory/inhibitory imbalance and the cognitive impairment in TgCHRNA5/A3/B4. Our results suggest that chronic nicotine treatment may represent a compensatory strategy in individuals with altered expression of the CHRNA5/A3/B4 region.
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16
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Stone TW, Darlington LG. The kynurenine pathway as a therapeutic target in cognitive and neurodegenerative disorders. Br J Pharmacol 2014; 169:1211-27. [PMID: 23647169 DOI: 10.1111/bph.12230] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/16/2013] [Accepted: 04/24/2013] [Indexed: 02/06/2023] Open
Abstract
Understanding the neurochemical basis for cognitive function is one of the major goals of neuroscience, with a potential impact on the diagnosis, prevention and treatment of a range of psychiatric and neurological disorders. In this review, the focus will be on a biochemical pathway that remains under-recognized in its implications for brain function, even though it can be responsible for moderating the activity of two neurotransmitters fundamentally involved in cognition - glutamate and acetylcholine. Since this pathway - the kynurenine pathway of tryptophan metabolism - is induced by immunological activation and stress, it also stands in a unique position to mediate the effects of environmental factors on cognition and behaviour. Targeting the pathway for new drug development could, therefore, be of value not only for the treatment of existing psychiatric conditions, but also for preventing the development of cognitive disorders in response to environmental pressures.
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Affiliation(s)
- Trevor W Stone
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK.
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17
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Molas S, Dierssen M. The role of nicotinic receptors in shaping and functioning of the glutamatergic system: a window into cognitive pathology. Neurosci Biobehav Rev 2014; 46 Pt 2:315-25. [PMID: 24879992 DOI: 10.1016/j.neubiorev.2014.05.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 04/13/2014] [Accepted: 05/20/2014] [Indexed: 10/25/2022]
Abstract
The involvement of the cholinergic system in learning, memory and attention has long been recognized, although its neurobiological mechanisms are not fully understood. Recent evidence identifies the endogenous cholinergic signaling via nicotinic acetylcholine receptors (nAChRs) as key players in determining the morphological and functional maturation of the glutamatergic system. Here, we review the available experimental and clinical evidence of nAChRs contribution to the establishment of the glutamatergic system, and therefore to cognitive function. We provide some clues of the putative underlying molecular mechanisms and discuss recent human studies that associate genetic variability of the genes encoding nAChR subunits with cognitive disorders. Finally, we discuss the new avenues to therapeutically targeting nAChRs in persons with cognitive dysfunction for which the α7-nAChR subunit is an important etiological mechanism.
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Affiliation(s)
- Susanna Molas
- Systems Biology Program, Centre for Genomic Regulation (CRG), Barcelona E-08003, Spain; University Pompeu Fabra (UPF), Spain; CIBER de Enfermedades Raras (CIBERER), Barcelona E-08003, Spain
| | - Mara Dierssen
- Systems Biology Program, Centre for Genomic Regulation (CRG), Barcelona E-08003, Spain; University Pompeu Fabra (UPF), Spain; CIBER de Enfermedades Raras (CIBERER), Barcelona E-08003, Spain.
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18
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Alkondon M, Albuquerque EX, Pereira EFR. Acetylcholinesterase inhibition reveals endogenous nicotinic modulation of glutamate inputs to CA1 stratum radiatum interneurons in hippocampal slices. Neurotoxicology 2013; 36:72-81. [PMID: 23511125 DOI: 10.1016/j.neuro.2013.02.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 02/15/2013] [Accepted: 02/16/2013] [Indexed: 10/27/2022]
Abstract
The involvement of brain nicotinic acetylcholine receptors (nAChRs) in the neurotoxicological effects of soman, a potent acetylcholinesterase (AChE) inhibitor and a chemical warfare agent, is not clear. This is partly due to a poor understanding of the role of AChE in brain nAChR-mediated functions. To test the hypothesis that AChE inhibition builds sufficient acetylcholine (ACh) in the brain and facilitates nAChR-dependent glutamate transmission, we used whole-cell patch-clamp technique to record spontaneous glutamate excitatory postsynaptic currents (EPSCs) from CA1 stratum radiatum interneurons (SRI) in hippocampal slices. First, the frequency, amplitude and kinetics of EPSCs recorded from slices of control guinea pigs were compared to those recorded from slices of guinea pigs after a single injection of the irreversible AChE inhibitor soman (25.2μg/kg, s.c.). Second, EPSCs were recorded from rat hippocampal slices before and after their superfusion with the reversible AChE inhibitor donepezil (100nM). The frequency of EPSCs was significantly higher in slices taken from guinea pigs 24h but not 7 days after the soman injection than in slices from control animals. In 52% of the rat hippocampal slices tested, bath application of donepezil increased the frequency of EPSCs. Further, exposure to donepezil increased both burst-like and large-amplitude EPSCs, and increased the proportion of short (20-100ms) inter-event intervals. Donepezil's effects were suppressed significantly in presence of 10μM mecamylamine or 10nM methyllycaconitine. These results support the concept that AChE inhibition is able to recruit nAChR-dependent glutamate transmission in the hippocampus and such a mechanism can contribute to the acute neurotoxicological actions of soman.
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Affiliation(s)
- Manickavasagom Alkondon
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, United States
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19
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Mrzljak L, Munoz-Sanjuan I. Therapeutic Strategies for Huntington's Disease. Curr Top Behav Neurosci 2013; 22:161-201. [PMID: 24277342 DOI: 10.1007/7854_2013_250] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Huntington's disease (HD) is a devastating autosomal dominant neurodegenerative disease, caused by expansion of the CAG repeat in the huntingtin (HTT) gene and characterized pathologically by the loss of pyramidal neurons in several cortical areas, of striatal medium spiny neurons, and of hypothalamic neurons. Clinically, a distinguishing feature of the disease is uncontrolled involuntary movements (chorea, dyskensias) accompanied by progressive cognitive, motor, and psychiatric impairment. This review focuses on the current state of therapeutic development for the treatment of HD, including the preclinical and clinical development of small molecules and molecular therapies.
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Albuquerque EX, Schwarcz R. Kynurenic acid as an antagonist of α7 nicotinic acetylcholine receptors in the brain: facts and challenges. Biochem Pharmacol 2012; 85:1027-32. [PMID: 23270993 DOI: 10.1016/j.bcp.2012.12.014] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 12/12/2012] [Accepted: 12/17/2012] [Indexed: 11/19/2022]
Abstract
Kynurenic acid (KYNA), a major tryptophan metabolite, is a glutamate receptor antagonist, which is also reported to inhibit α7 nicotinic acetylcholine receptors (α7nAChRs). Due to variations in experimental approaches, controversy has arisen regarding the ability of KYNA to directly influence α7nAChR function. Here we summarize current concepts of KYNA neurobiology and review evidence pertaining to the proposed role of KYNA as an endogenous modulator of α7nAChRs and synaptic transmission. As dysfunction of α7nAChRs plays a major role in the pathophysiology of central nervous system disorders, elucidation of KYNA's action on this receptor subtype has significant therapeutic implications.
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Affiliation(s)
- Edson X Albuquerque
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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21
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Stone TW, Stoy N, Darlington LG. An expanding range of targets for kynurenine metabolites of tryptophan. Trends Pharmacol Sci 2012; 34:136-43. [PMID: 23123095 DOI: 10.1016/j.tips.2012.09.006] [Citation(s) in RCA: 202] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 09/27/2012] [Accepted: 09/27/2012] [Indexed: 12/14/2022]
Abstract
The kynurenine pathway of tryptophan metabolism accounts for most of the tryptophan that is not committed to protein synthesis and includes compounds active in the nervous and immune systems. Kynurenine acts on the aryl hydrocarbon receptor, affecting the metabolism of xenobiotics and promoting carcinogenesis. Quinolinic acid is an agonist at N-methyl-D-aspartate receptors (NMDARs), but is also pro-oxidant, has immunomodulatory actions, and promotes the formation of hyperphosphorylated tau proteins. Kynurenic acid blocks NMDARs and α7-homomeric nicotinic cholinoceptors and is also an agonist at the orphan G-protein-coupled receptor GPR35. 3-Hydroxykynurenine and 3-hydroxyanthranilic acid have pronounced redox activity and regulate T cell function. Cinnabarinic acid can activate metabotropic glutamate receptors. This review highlights the increasing range of molecular targets for components of the kynurenine pathway in both the nervous and immune systems in relation to their relevance to disease and drug development.
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Affiliation(s)
- Trevor W Stone
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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Banerjee J, Alkondon M, Albuquerque EX. Kynurenic acid inhibits glutamatergic transmission to CA1 pyramidal neurons via α7 nAChR-dependent and -independent mechanisms. Biochem Pharmacol 2012; 84:1078-87. [PMID: 22889930 DOI: 10.1016/j.bcp.2012.07.030] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 07/24/2012] [Accepted: 07/26/2012] [Indexed: 01/17/2023]
Abstract
Glutamatergic hypofunction and elevated levels of kynurenic acid (KYNA) in the brain are common features of patients with schizophrenia. In vivo studies indicate that in the hippocampus KYNA decreases glutamate levels, presumably via inhibition of α7 nicotinic receptors (nAChRs). Here we tested the hypothesis that basal synaptic glutamate activity in the hippocampus is regulated by tonically active α7 nAChRs and is sensitive to inhibition by KYNA. To this end, spontaneous excitatory postsynaptic currents (EPSCs), sensitive to AMPA receptor antagonist CNQX (10 μM), were recorded from CA1 pyramidal neurons at -70 mV in rat hippocampal slices. The α7 nAChR antagonists α-bungarotoxin (α-BGT, 100 nM) and methyllycaconitine (MLA, 1-50 nM), and the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid (APV, 50 μM) reduced the frequency of EPSCs. MLA and α-BGT had no effect on miniature EPSCs (mEPSCs). The effect of MLA decreased in the presence of APV (50 μM), with 1 nM MLA becoming completely ineffective. KYNA (1-20 μM) suppressed the frequency of EPSCs, without affecting mEPSCs. The effect of KYNA decreased in the presence of MLA (1 nM) or α-BGT (100 nM), with 1 μM KYNA being devoid of any effect. In the presence of both MLA (10 nM) and APV (50 μM) higher KYNA concentrations (5-20 μM) still reduced the frequency of EPSCs. These results suggest that basal synaptic glutamate activity in CA1 pyramidal neurons is maintained in part by tonically active α7 nAChRs and NMDA receptors and is inhibited by micromolar concentrations of KYNA, acting via α7 nAChR-dependent and -independent mechanisms.
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Affiliation(s)
- Jyotirmoy Banerjee
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Dobelis P, Staley KJ, Cooper DC. Lack of modulation of nicotinic acetylcholine alpha-7 receptor currents by kynurenic acid in adult hippocampal interneurons. PLoS One 2012; 7:e41108. [PMID: 22848433 PMCID: PMC3405093 DOI: 10.1371/journal.pone.0041108] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 06/21/2012] [Indexed: 11/17/2022] Open
Abstract
Kynurenic acid (KYNA), a classical ionotropic glutamate receptor antagonist is also purported to block the α7-subtype nicotinic acetylcholine receptor (α7* nAChR). Although many published studies cite this potential effect, few have studied it directly. In this study, the α7*-selective agonist, choline, was pressure-applied to interneurons in hippocampal subregions, CA1 stratum radiatum and hilus of acute brain hippocampal slices from adolescent to adult mice and adolescent rats. Stable α7* mediated whole-cell currents were measured using voltage-clamp at physiological temperatures. The effects of bath applied KYNA on spontaneous glutamatergic excitatory postsynaptic potentials (sEPSC) as well as choline-evoked α7* currents were determined. In mouse hilar interneurons, KYNA totally blocked sEPSC whole-cell currents in a rapid and reversible manner, but had no effect on choline-evoked α7* whole-cell currents. To determine if this lack of KYNA effect on α7* function was due to regional and/or species differences in α7* nAChRs, the effects of KYNA on choline-evoked α7* whole-cell currents in mouse and rat stratum radiatum interneurons were tested. KYNA had no effect on either mouse or rat stratum radiatum interneuron choline-evoked α7* whole-cell currents. Finally, to test whether the lack of effect of KYNA was due to unlikely slow kinetics of KYNA interactions with α7* nAChRs, recordings of a7*-mediated currents were made from slices that were prepared and stored in the presence of 1 mM KYNA (>90 minutes exposure). Under these conditions, KYNA had no measurable effect on α7* nAChR function. The results show that despite KYNA-mediated blockade of glutamatergic sEPSCs, two types of hippocampal interneurons that express choline-evoked α7* nAChR currents fail to show any degree of modulation by KYNA. Our results indicate that under our experimental conditions, which produced complete KYNA-mediated blockade of sEPSCs, claims of KYNA effects on choline-evoked α7* nAChR function should be made with caution.
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Affiliation(s)
- Peter Dobelis
- Center for Neuroscience, Institute for Behavioral Genetics, Department of Neuroscience, University of Colorado at Boulder, Boulder, Colorado, United States of America
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Banerjee J, Alkondon M, Pereira EFR, Albuquerque EX. Regulation of GABAergic inputs to CA1 pyramidal neurons by nicotinic receptors and kynurenic acid. J Pharmacol Exp Ther 2012; 341:500-9. [PMID: 22344459 DOI: 10.1124/jpet.111.189860] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Impaired α7 nicotinic acetylcholine receptor (nAChR) function and GABAergic transmission in the hippocampus and elevated brain levels of kynurenic acid (KYNA), an astrocyte-derived metabolite of the kynurenine pathway, are key features of schizophrenia. KYNA acts as a noncompetitive antagonist with respect to agonists at both α7 nAChRs and N-methyl-D-aspartate receptors. Here, we tested the hypothesis that in hippocampal slices tonically active α7 nAChRs control GABAergic transmission to CA1 pyramidal neurons and are sensitive to inhibition by rising levels of KYNA. The α7 nAChR-selective antagonist α-bungarotoxin (α-BGT; 100 nM) and methyllycaconitine (MLA; 10 nM), an antagonist at α7 and other nAChRs, reduced by 51.3 ± 1.3 and 65.2 ± 1.5%, respectively, the frequency of GABAergic postsynaptic currents (PSCs) recorded from CA1 pyramidal neurons. MLA had no effect on miniature GABAergic PSCs. Thus, GABAergic synaptic activity in CA1 pyramidal neurons is maintained, in part, by tonically active α7 nAChRs located on the preterminal region of axons and/or the somatodendritic region of interneurons that synapse onto the neurons under study. L-Kynurenine (20 or 200 μM) or KYNA (20-200 μM) suppressed concentration-dependently the frequency of GABAergic PSCs; the inhibitory effect of 20 μM L-kynurenine had an onset time of approximately 35 min and could not be detected in the presence of 100 nM α-BGT. These results suggest that KYNA levels generated from 20 μM kynurenine inhibit tonically active α7 nAChR-dependent GABAergic transmission to the pyramidal neurons. Disruption of nAChR-dependent GABAergic transmission by mildly elevated levels of KYNA can be an important determinant of the cognitive deficits presented by patients with schizophrenia.
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Affiliation(s)
- Jyotirmoy Banerjee
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
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Griguoli M, Cherubini E. Regulation of hippocampal inhibitory circuits by nicotinic acetylcholine receptors. J Physiol 2012; 590:655-66. [PMID: 22124144 PMCID: PMC3381299 DOI: 10.1113/jphysiol.2011.220095] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2011] [Accepted: 11/24/2011] [Indexed: 11/08/2022] Open
Abstract
The hippocampal network comprises a large variety of locally connected GABAergic interneurons exerting a powerful control on network excitability and which are responsible for the oscillatory behaviour crucial for information processing. GABAergic interneurons receive an important cholinergic innervation from the medial septum-diagonal band complex of the basal forebrain and are endowed with a variety of muscarinic and nicotinic acetylcholine receptors (mAChRs and nAChRs) that regulate their activity. Deficits in the cholinergic system lead to the impairment of high cognitive functions, which are particularly relevant in neurodegenerative pathologies such as Alzheimer's and Parkinson's diseases as well as in schizophrenia. Here, we highlight some recent advances in the mechanisms by which cholinergic signalling via nAChRs regulates local inhibitory circuits in the hippocampus, early in postnatal life and in adulthood. We also discuss recent findings concerning the functional role of nAChRs in controlling short- and long-term modifications of synaptic efficacy. Insights into these processes may provide new targets for the therapeutic control of pathological conditions associated with cholinergic dysfunctions.
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Affiliation(s)
- Marilena Griguoli
- Neuroscience Programme, International School for Advanced Studies (SISSA), via Bonomea 265, 34136 Trieste, Italy
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