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Liu HW, Gong LN, Lai K, Yu XF, Liu ZQ, Li MX, Yin XL, Liang M, Shi HS, Jiang LH, Yang W, Shi HB, Wang LY, Yin SK. Bilirubin gates the TRPM2 channel as a direct agonist to exacerbate ischemic brain damage. Neuron 2023; 111:1609-1625.e6. [PMID: 36921602 DOI: 10.1016/j.neuron.2023.02.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 10/18/2022] [Accepted: 02/13/2023] [Indexed: 03/16/2023]
Abstract
Stroke prognosis is negatively associated with an elevation of serum bilirubin, but how bilirubin worsens outcomes remains mysterious. We report that post-, but not pre-, stroke bilirubin levels among inpatients scale with infarct volume. In mouse models, bilirubin increases neuronal excitability and ischemic infarct, whereas ischemic insults induce the release of endogenous bilirubin, all of which are attenuated by knockout of the TRPM2 channel or its antagonist A23. Independent of canonical TRPM2 intracellular agonists, bilirubin and its metabolic derivatives gate the channel opening, whereas A23 antagonizes it by binding to the same cavity. Knocking in a loss of binding point mutation for bilirubin, TRPM2-D1066A, effectively antagonizes ischemic neurotoxicity in mice. These findings suggest a vicious cycle of stroke injury in which initial ischemic insults trigger the release of endogenous bilirubin from injured cells, which potentially acts as a volume neurotransmitter to activate TRPM2 channels, aggravating Ca2+-dependent brain injury.
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Affiliation(s)
- Han-Wei Liu
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
| | - Li-Na Gong
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
| | - Ke Lai
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China; Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Xia-Fei Yu
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Zhen-Qi Liu
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China; Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ming-Xian Li
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
| | - Xin-Lu Yin
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China; Department of Head & Neck Surgery, Renji Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Min Liang
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China; Department of Otorhinolaryngology Head & Neck Surgery, Xinhua Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Hao-Song Shi
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
| | - Lin-Hua Jiang
- Department of Physiology and Pathophysiology, School of Basic Sciences, Xinxiang Medical University, Xinxiang, Henan Province 453003, China; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Wei Yang
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Hai-Bo Shi
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China.
| | - Lu-Yang Wang
- Program in Neuroscience and Mental Health, SickKids Research Institute, Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Shan-Kai Yin
- Department of Otorhinolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital and Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China.
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2
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Yang F, Sivils A, Cegielski V, Singh S, Chu XP. Transient Receptor Potential (TRP) Channels in Pain, Neuropsychiatric Disorders, and Epilepsy. Int J Mol Sci 2023; 24:ijms24054714. [PMID: 36902145 PMCID: PMC10003176 DOI: 10.3390/ijms24054714] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/05/2023] Open
Abstract
Pharmacomodulation of membrane channels is an essential topic in the study of physiological conditions and disease status. Transient receptor potential (TRP) channels are one such family of nonselective cation channels that have an important influence. In mammals, TRP channels consist of seven subfamilies with a total of twenty-eight members. Evidence shows that TRP channels mediate cation transduction in neuronal signaling, but the full implication and potential therapeutic applications of this are not entirely clear. In this review, we aim to highlight several TRP channels which have been shown to mediate pain sensation, neuropsychiatric disorders, and epilepsy. Recent findings suggest that TRPM (melastatin), TRPV (vanilloid), and TRPC (canonical) are of particular relevance to these phenomena. The research reviewed in this paper validates these TRP channels as potential targets of future clinical treatment and offers patients hope for more effective care.
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Ying Y, Gong L, Tao X, Ding J, Chen N, Yao Y, Liu J, Chen C, Zhu T, Jiang P. Genetic Knockout of TRPM2 Increases Neuronal Excitability of Hippocampal Neurons by Inhibiting Kv7 Channel in Epilepsy. Mol Neurobiol 2022; 59:6918-6933. [PMID: 36053438 DOI: 10.1007/s12035-022-02993-2] [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: 04/26/2022] [Accepted: 08/07/2022] [Indexed: 11/30/2022]
Abstract
Epilepsy is a chronic brain disease that makes serious cognitive and motor retardation. Ion channels affect the occurrence of epilepsy in various ways, but the mechanisms have not yet been fully elucidated. Transient receptor potential melastain2 (TRPM2) ion channel is a non-selective cationic channel that can permeate Ca2+ and critical for epilepsy. Here, TRPM2 gene knockout mice were used to generate a chronic kindling epilepsy model by PTZ administration in mice. We found that TRPM2 knockout mice were more susceptible to epilepsy than WT mice. Furthermore, the neuronal excitability in the hippocampal CA1 region of TRPM2 knockout mice was significantly increased. Compared with WT group, there were no significant differences in the input resistance and after hyperpolarization of CA1 neurons in TRPM2 knockout mice. Firing adaptation rate of hippocampal CA1 pyramidal neurons of TRPM2 knockout mice was lower than that of WT mice. We also found that activation of Kv7 channel by retigabine reduced the firing frequency of action potential in the hippocampal pyramidal neurons of TRPM2 knockout mice. However, inhibiting Kv7 channel increased the firing frequency of action potential in hippocampal pyramidal neurons of WT mice. The data suggest that activation of Kv7 channel can effectively reduce epileptic seizures in TRPM2 knockout mice. We conclude that genetic knockout of TRPM2 in hippocampal CA1 pyramidal neurons may increase neuronal excitability by inhibiting Kv7 channel, affecting the susceptibility to epilepsy. These findings may provide a potential therapeutic target for epilepsy.
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Affiliation(s)
- Yingchao Ying
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Lifen Gong
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Xiaohan Tao
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Junchao Ding
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
- Department of Pediatrics, Yiwu Maternal and Child Health Care Hospital, Yiwu, China
| | - Nannan Chen
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Yinping Yao
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
- Department of Pediatrics, Shaoxing People's Hospital, Shaoxing, China
| | - Jiajing Liu
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Chen Chen
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Tao Zhu
- Department of Critical Care Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Peifang Jiang
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China.
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Rosenbaum T, Morales-Lázaro SL, Islas LD. TRP channels: a journey towards a molecular understanding of pain. Nat Rev Neurosci 2022; 23:596-610. [PMID: 35831443 DOI: 10.1038/s41583-022-00611-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2022] [Indexed: 12/18/2022]
Abstract
The perception of nociceptive signals, which are translated into pain, plays a fundamental role in the survival of organisms. Because pain is linked to a negative sensation, animals learn to avoid noxious signals. These signals are detected by receptors, which include some members of the transient receptor potential (TRP) family of ion channels that act as transducers of exogenous and endogenous noxious cues. These proteins have been in the focus of the field of physiology for several years, and much knowledge of how they regulate the function of the cell types and organs where they are expressed has been acquired. The last decade has been especially exciting because the 'resolution revolution' has allowed us to learn the molecular intimacies of TRP channels using cryogenic electron microscopy. These findings, in combination with functional studies, have provided insights into the role played by these channels in the generation and maintenance of pain.
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Affiliation(s)
- Tamara Rosenbaum
- Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, UNAM, Mexico City, Mexico.
| | - Sara L Morales-Lázaro
- Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, UNAM, Mexico City, Mexico
| | - León D Islas
- Departamento de Fisiología, Facultad de Medicina, UNAM, Mexico City, Mexico
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Hikima T, Witkovsky P, Khatri L, Chao MV, Rice ME. Synaptotagmins 1 and 7 Play Complementary Roles in Somatodendritic Dopamine Release. J Neurosci 2022; 42:3919-3930. [PMID: 35361702 PMCID: PMC9097777 DOI: 10.1523/jneurosci.2416-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/18/2022] [Accepted: 03/18/2022] [Indexed: 11/21/2022] Open
Abstract
The molecular mechanisms underlying somatodendritic dopamine (DA) release remain unresolved, despite the passing of decades since its discovery. Our previous work showed robust release of somatodendritic DA in submillimolar extracellular Ca2+ concentration ([Ca2+]o). Here we tested the hypothesis that the high-affinity Ca2+ sensor synaptotagmin 7 (Syt7), is a key determinant of somatodendritic DA release and its Ca2+ dependence. Somatodendritic DA release from SNc DA neurons was assessed using whole-cell recording in midbrain slices from male and female mice to monitor evoked DA-dependent D2 receptor-mediated inhibitory currents (D2ICs). Single-cell application of an antibody to Syt7 (Syt7 Ab) decreased pulse train-evoked D2ICs, revealing a functional role for Syt7. The assessment of the Ca2+ dependence of pulse train-evoked D2ICs confirmed robust DA release in submillimolar [Ca2+]o in wild-type (WT) neurons, but loss of this sensitivity with intracellular Syt7 Ab or in Syt7 knock-out (KO) mice. In millimolar [Ca2+]o, pulse train-evoked D2ICs in Syt7 KOs showed a greater reduction in decreased [Ca2+]o than seen in WT mice; the effect on single pulse-evoked DA release, however, did not differ between genotypes. Single-cell application of a Syt1 Ab had no effect on train-evoked D2ICs in WT SNc DA neurons, but did cause a decrease in D2IC amplitude in Syt7 KOs, indicating a functional substitution of Syt1 for Syt7. In addition, Syt1 Ab decreased single pulse-evoked D2ICs in WT cells, indicating the involvement of Syt1 in tonic DA release. Thus, Syt7 and Syt1 play complementary roles in somatodendritic DA release from SNc DA neurons.SIGNIFICANCE STATEMENT The respective Ca2+ dependence of somatodendritic and axonal dopamine (DA) release differs, resulting in the persistence of somatodendritic DA release in submillimolar Ca2+ concentrations too low to support axonal release. We demonstrate that synaptotagmin7 (Syt7), a high-affinity Ca2+ sensor, underlies phasic somatodendritic DA release and its Ca2+ sensitivity in the substantia nigra pars compacta. In contrast, we found that synaptotagmin 1 (Syt1), the Ca2+ sensor underlying axonal DA release, plays a role in tonic, but not phasic, somatodendritic DA release in wild-type mice. However, Syt1 can facilitate phasic DA release after Syt7 deletion. Thus, we show that both Syt1 and Syt7 act as Ca2+ sensors subserving different aspects of somatodendritic DA release processes.
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Affiliation(s)
- Takuya Hikima
- Department of Neurosurgery, New York University Grossman School of Medicine, New York, New York 10016
| | - Paul Witkovsky
- Department of Neurosurgery, New York University Grossman School of Medicine, New York, New York 10016
| | - Latika Khatri
- Department of Cell Biology, New York University Grossman School of Medicine, New York, New York 10016
| | - Moses V Chao
- Department of Cell Biology, New York University Grossman School of Medicine, New York, New York 10016
- Department of Psychiatry, New York University Grossman School of Medicine, New York, New York 10016
- Department of Neuroscience & Physiology, New York University Grossman School of Medicine, New York, New York 10016
| | - Margaret E Rice
- Department of Neurosurgery, New York University Grossman School of Medicine, New York, New York 10016
- Department of Neuroscience & Physiology, New York University Grossman School of Medicine, New York, New York 10016
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6
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Chauhan-Puri AK, Lee KH, Magoski NS. Hydrogen peroxide and phosphoinositide metabolites synergistically regulate a cation current to influence neuroendocrine cell bursting. J Physiol 2021; 599:5281-5300. [PMID: 34676545 DOI: 10.1113/jp282302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/07/2021] [Indexed: 11/08/2022] Open
Abstract
In various neurons, including neuroendocrine cells, non-selective cation channels elicit plateau potentials and persistent firing. Reproduction in the marine snail Aplysia californica is initiated when the neuroendocrine bag cell neurons undergo an afterdischarge, that is, a prolonged period of enhanced excitability and spiking during which egg-laying hormone is released into the blood. The afterdischarge is associated with both the production of hydrogen peroxide (H2 O2 ) and activation of phospholipase C (PLC), which hydrolyses phosphatidylinositol-4,5-bisphosphate into diacylglycerol (DAG) and inositol trisphosphate (IP3 ). We previously demonstrated that H2 O2 gates a voltage-dependent cation current and evokes spiking in bag cell neurons. The present study tests if DAG and IP3 impact the H2 O2 -induced current and excitability. In whole-cell voltage-clamped cultured bag cell neurons, bath-application of 1-oleoyl-2-acetyl-sn-glycerol (OAG), a DAG analogue, enhanced the H2 O2 -induced current, which was amplified by the inclusion of IP3 in the pipette. A similar outcome was produced by the PLC activator, N-(3-trifluoromethylphenyl)-2,4,6-trimethylbenzenesulfonamide. In current-clamp, OAG or OAG plus IP3 , elevated the frequency of H2 O2 -induced bursting. PKC is also triggered during the afterdischarge; when PKC was stimulated with phorbol 12-myristate 13-acetate, it caused a voltage-dependent inward current with a reversal potential similar to the H2 O2 -induced current. Furthermore, PKC activation followed by H2 O2 reduced the onset latency and increased the duration of action potential firing. Finally, inhibiting nicotinamide adenine dinucleotide phosphate oxidase with 3-benzyl-7-(2-benzoxazolyl)thio-1,2,3-triazolo[4,5-d]pyrimidine diminished evoked bursting in isolated bag cell neuron clusters. These results suggest that reactive oxygen species and phosphoinostide metabolites may synergize and contribute to reproductive behaviour by promoting neuroendocrine cell firing. KEY POINTS: Aplysia bag cell neurons secrete reproductive hormone during a lengthy burst of action potentials, known as the afterdischarge. During the afterdischarge, phospholipase C (PLC) hydrolyses phosphatidylinositol-4,5-bisphosphate into diacylglycerol (DAG) and inositol trisphosphate (IP3 ). Subsequent activation of protein kinase C (PKC) leads to H2 O2 production. H2 O2 evokes a voltage-dependent inward current and action potential firing. Both a DAG analogue, 1-oleoyl-2-acetyl-sn-glycerol (OAG), and IP3 enhance the H2 O2 -induced current, which is mimicked by the PLC activator, N-(3-trifluoromethylphenyl)-2,4,6-trimethylbenzenesulfonamide. The frequency of H2 O2 -evoked afterdischarge-like bursting is augmented by OAG or OAG plus IP3 . Stimulating PKC with phorbol 12-myristate 13-acetate shortens the latency and increases the duration of H2 O2 -induced bursts. The nicotinamide adenine dinucleotide phosphate oxidase inhibitor, 3-benzyl-7-(2-benzoxazolyl)thio-1,2,3-triazolo[4,5-d]pyrimidine, attenuates burst firing in bag cell neuron clusters.
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Affiliation(s)
- Alamjeet K Chauhan-Puri
- Department of Biomedical and Molecular Sciences, Experimental Medicine Graduate Program, Queen's University, Kingston, Ontario, Canada
| | - Kelly H Lee
- Department of Biomedical and Molecular Sciences, Experimental Medicine Graduate Program, Queen's University, Kingston, Ontario, Canada
| | - Neil S Magoski
- Department of Biomedical and Molecular Sciences, Experimental Medicine Graduate Program, Queen's University, Kingston, Ontario, Canada
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Ying Y, Jiang P. Research progress on transient receptor potential melastatin 2 channel in nervous system diseases. Zhejiang Da Xue Xue Bao Yi Xue Ban 2021; 50:267-276. [PMID: 34137233 PMCID: PMC8710270 DOI: 10.3724/zdxbyxb-2021-0110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/30/2021] [Indexed: 11/25/2022]
Abstract
Transient receptor potential M2 (TRPM2) ion channel is a non-selective cationic channel that can permeate calcium ions, and plays an important role in neuroinflammation, ischemic reperfusion brain injury, neurodegenerative disease, neuropathic pain, epilepsy and other neurological diseases. In ischemic reperfusion brain injury, TRPM2 mediates neuronal death by modulating the different subunits of glutamate N-methyl-D-aspartic acid receptor in response to calcium/zinc signal. In Alzheimer's disease, TRPM2 is activated by reactive oxygen species generated by β-amyloid peptide to form a malignant positive feedback loop that induces neuronal death and is involved in the pathological process of glial cells by promoting inflammatory response and oxidative stress. In epilepsy, the TRPM2-knockout alleviates epilepsy induced neuronal degeneration by inhibiting autophagy and apoptosis related proteins. The roles of TRPM2 channel in the pathogenesis of various central nervous system diseases and its potential drug development and clinical application prospects are summarized in this review.
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Hikima T, Lee CR, Witkovsky P, Chesler J, Ichtchenko K, Rice ME. Activity-dependent somatodendritic dopamine release in the substantia nigra autoinhibits the releasing neuron. Cell Rep 2021; 35:108951. [PMID: 33826884 PMCID: PMC8189326 DOI: 10.1016/j.celrep.2021.108951] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/20/2020] [Accepted: 03/15/2021] [Indexed: 12/12/2022] Open
Abstract
Somatodendritic dopamine (DA) release from midbrain DA neurons activates D2 autoreceptors on these cells to regulate their activity. However, the source of autoregulatory DA remains controversial. Here, we test the hypothesis that D2 autoreceptors on a given DA neuron in the substantia nigra pars compacta (SNc) are activated primarily by DA released from that same cell, rather than from its neighbors. Voltage-clamp recording allows monitoring of evoked D2-receptor-mediated inhibitory currents (D2ICs) in SNc DA neurons as an index of DA release. Single-cell application of antibodies to Na+ channels via the recording pipette decreases spontaneous activity of recorded neurons and attenuates evoked D2ICs; antibodies to SNAP-25, a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein, also decrease D2IC amplitude. Evoked D2ICs are nearly abolished by the light chain of botulinum neurotoxin A, which cleaves SNAP-25, whereas synaptically activated GABAB-receptor-mediated currents are unaffected. Thus, somatodendritic DA release in the SNc autoinhibits the neuron that releases it.
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Affiliation(s)
- Takuya Hikima
- Department of Neurosurgery, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Christian R Lee
- Department of Neurosurgery, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Paul Witkovsky
- Department of Neurosurgery, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Julia Chesler
- Department of Neurosurgery, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Konstantin Ichtchenko
- Department of Biochemistry & Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Margaret E Rice
- Department of Neurosurgery, New York University Grossman School of Medicine, New York, NY 10016, USA; Department of Neuroscience & Physiology, New York University Grossman School of Medicine, New York, NY 10016, USA.
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Involvement of NMDA and GABA(A) receptors in modulation of spontaneous activity in hippocampal culture: Interrelations between burst firing and intracellular calcium signal. Biochem Biophys Res Commun 2021; 553:99-106. [PMID: 33765560 DOI: 10.1016/j.bbrc.2021.02.149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/28/2022]
Abstract
Spontaneous burst firing is a hallmark attributed to the neuronal network activity. It is known to be accompanied by intracellular calcium [Са2+]i oscillations within the bursting neurons. Studying mechanisms underlying regulation of burst firing is highly relevant, since impairment in neuronal bursting accompanies different neurological disorders. In the present study, the contribution of NMDA and GABA(A) receptors to the shape formation of spontaneous burst -was studied in cultured hippocampal neurons. A combination of inhibitory analysis with simultaneous registration of neuronal bursting by whole-cell patch clamp and calcium imaging was used to assess spontaneous burst firing and [Са2+]i level. Using bicuculline and D-AP5 we showed that GABA(A) and NMDA receptors effectively modulate burst plateau phase and [Са2+]i transient spike which can further affect action potential (AP) amplitudes and firing frequency within a burst. Bicuculline significantly elevated the amplitude and reduced the duration of both burst plateau phase and [Са2+]i spike resulting in an increase of AP firing frequency and shortening of AP amplitudes within a burst. D-AP5 significantly decreases the amplitude of both plateau phase and [Са2+]i spike along with a burst duration that correlated with an increase in AP amplitudes and reduced firing frequency within a burst. The effect of bicuculline was occluded by co-addition of D-AP5 revealing modulatory role of GABA(A) receptors to the NMDA receptor-mediated formation of the burst. Our results provide new evidence on importance of NMDA and GABA(A) receptors in shaping burst firing and Ca2+transient spikes in cultured hippocampal neurons.
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10
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Nakao A, Matsunaga Y, Hayashida K, Takahashi N. Role of Oxidative Stress and Ca 2+ Signaling in Psychiatric Disorders. Front Cell Dev Biol 2021; 9:615569. [PMID: 33644051 PMCID: PMC7905097 DOI: 10.3389/fcell.2021.615569] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/25/2021] [Indexed: 12/21/2022] Open
Abstract
Psychiatric disorders are caused by complex and diverse factors, and numerous mechanisms have been proposed for the pathogenesis of these disorders. Accumulating evidence suggests that oxidative stress is one of the general factors involved in the pathogenesis/pathophysiology of major psychiatric disorders, including bipolar disorder, depression, anxiety disorder, and schizophrenia. Indeed, some clinical trials have shown improvement of the symptoms of these disorders by antioxidant supplementation. However, the molecular basis for the relationship between oxidative stress and the pathogenesis of psychiatric disorders remains largely unknown. In general, Ca2+ channels play central roles in neuronal functions, including neuronal excitability, neurotransmitter release, synaptic plasticity, and gene regulation, and genes that encode Ca2+ channels have been found to be associated with psychiatric disorders. Notably, a class of Ca2+-permeable transient receptor potential (TRP) cation channels is activated by changes in cellular redox status, whereby these TRP channels can link oxidative stress to Ca2+ signals. Given the unique characteristic of redox-sensitive TRP channels, these channels could be a target for delineating the pathogenesis or pathophysiology of psychiatric disorders. In this review, we summarize the outcomes of clinical trials for antioxidant treatment in patients with psychiatric disorders and the current insights into the physiological/pathological significance of redox-sensitive TRP channels in the light of neural functions, including behavioral phenotypes, and discuss the potential role of TRP channels in the pathogenesis of psychiatric disorders. Investigation of redox-sensitive TRP channels may lead to the development of novel therapeutic strategies for the treatment of psychiatric disorders.
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Affiliation(s)
- Akito Nakao
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Yoshihiro Matsunaga
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Katsumi Hayashida
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Nobuaki Takahashi
- The Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan
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11
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Yildirim C, Özkaya B, Bal R. KATP and TRPM2-like channels couple metabolic status to resting membrane potential of octopus neurons in the mouse ventral cochlear nucleus. Brain Res Bull 2021; 170:115-128. [PMID: 33581312 DOI: 10.1016/j.brainresbull.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/29/2022]
Abstract
ATP-sensitive potassium (KATP) channels and transient receptor potential melastatin 2 (TRPM2) channels are commonly expressed both pre- and postsynaptically in the central nervous system (CNS). We hypothesized that KATP and TRPM2 may couple metabolic status to the resting membrane potential of octopus neurons of the mouse ventral cochlear nucleus (VCN). Therefore, we studied the expression of KATP channels and TRPM2 channels in octopus cells by immunohistochemical techniques and their contribution to neuronal electrical properties by the electrophysiological patch clamp technique. In immunohistochemical staining of octopus cells, labelling with Kir6.2 and SUR1 antibodies was strong, and labelling with the SUR2 antibody was moderate, but labelling with Kir6.1 was very weak. Octopus cells had intense staining with TRPM2 antibodies. In patch clamp recordings, bath application of KATP channel agonists H2O2 (880 μM), ATZ (1 mM), cromakalim (50 μM), diazoxide (200 μM), NNC 55-0118 and NN 414 separately resulted in hyperpolarizations of resting potential to different extents. Application of 8-Bro-cADPR (50 μM), a specific antagonist of TRPM2 channels, in the presence of H2O2 (880 μM) resulted in further hyperpolarization by approximately 1 mV. The amplitudes of H2O2-induced outward KATP currents and ADPR-induced inward currents were 206.1 ± 31.5 pA (n = 4) and 136.8 ± 22.4 pA, respectively, at rest. Their respective reversal potentials were -77 ± 2.6 mV (n = 3) and -6.3 ± 2.9 (n = 3) and -6.3 ± 2.9 (n = 3). In conclusion, octopus cells appear to possess both KATP channels and TRPM2-like channels. KATP might largely be constituted by SUR1-Kir6.2 subunits and SUR2-Kir6.2 subunits. Both KATP and TRPM2-like channels might have a modulatory action in setting the membrane potential.
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Affiliation(s)
- Caner Yildirim
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey
| | - Beytullah Özkaya
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey
| | - Ramazan Bal
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey.
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Genome-wide Association Analysis of Parkinson's Disease and Schizophrenia Reveals Shared Genetic Architecture and Identifies Novel Risk Loci. Biol Psychiatry 2021; 89:227-235. [PMID: 32201043 PMCID: PMC7416467 DOI: 10.1016/j.biopsych.2020.01.026] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 01/14/2020] [Accepted: 01/30/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Parkinson's disease (PD) and schizophrenia (SCZ) are heritable brain disorders that involve dysregulation of the dopaminergic system. Epidemiological studies have reported potential comorbidity between the disorders, and movement disturbances are common in patients with SCZ before treatment with antipsychotic drugs. Despite this, little is known about shared genetic etiology between the disorders. METHODS We analyzed recent large genome-wide association studies on patients with SCZ (N = 77,096) and PD (N = 417,508) using a conditional/conjunctional false discovery rate (FDR) approach to evaluate overlap in common genetic variants and improve statistical power for genetic discovery. Using a variety of biological resources, we functionally characterized the identified genomic loci. RESULTS We observed genetic enrichment in PD conditional on associations with SCZ and vice versa, indicating polygenic overlap. We then leveraged this cross-trait enrichment using conditional FDR analysis and identified 9 novel PD risk loci and 1 novel SCZ locus at conditional FDR < .01. Furthermore, we identified 9 genomic loci jointly associated with PD and SCZ at conjunctional FDR < .05. There was an even distribution of antagonistic and agonistic effect directions among the shared loci, in line with the insignificant genetic correlation between the disorders. Of 67 genes mapped to the shared loci, 65 are expressed in the human brain and show cell type-specific expression profiles. CONCLUSIONS Altogether, the study increases understanding of the genetic architectures underlying SCZ and PD, indicating that common molecular genetic mechanisms may contribute to overlapping pathophysiological and clinical features between the disorders.
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Vaidya B, Sharma SS. Transient Receptor Potential Channels as an Emerging Target for the Treatment of Parkinson's Disease: An Insight Into Role of Pharmacological Interventions. Front Cell Dev Biol 2020; 8:584513. [PMID: 33330461 PMCID: PMC7714790 DOI: 10.3389/fcell.2020.584513] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/30/2020] [Indexed: 12/21/2022] Open
Abstract
Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the symptoms of motor deficits and cognitive decline. There are a number of therapeutics available for the treatment of PD, but most of them suffer from serious side effects such as bradykinesia, dyskinesia and on-off effect. Therefore, despite the availability of these pharmacological agents, PD patients continue to have an inferior quality of life. This has warranted a need to look for alternate strategies and molecular targets. Recent evidence suggests the Transient Receptor Potential (TRP) channels could be a potential target for the management of motor and non-motor symptoms of PD. Though still in the preclinical stages, agents targeting these channels have shown immense potential in the attenuation of behavioral deficits and signaling pathways. In addition, these channels are known to be involved in the regulation of ionic homeostasis, which is disrupted in PD. Moreover, activation or inhibition of many of the TRP channels by calcium and oxidative stress has also raised the possibility of their paramount involvement in affecting the other molecular mechanisms associated with PD pathology. However, due to the paucity of information available and lack of specificity, none of these agents have gone into clinical trials for PD treatment. Considering their interaction with oxidative stress, apoptosis and excitotoxicity, TRP channels could be considered as a potential future target for the treatment of PD.
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Affiliation(s)
- Bhupesh Vaidya
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Mohali, India
| | - Shyam Sunder Sharma
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Mohali, India
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Roles of TRP Channels in Neurological Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:7289194. [PMID: 32963700 PMCID: PMC7492880 DOI: 10.1155/2020/7289194] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/02/2020] [Indexed: 11/17/2022]
Abstract
Transient receptor potential (TRP) proteins consist of a superfamily of cation channels that have been involved in diverse physiological processes in the brain as well as in the pathogenesis of neurological disease. TRP channels are widely expressed in the brain, including neurons and glial cells, as well as in the cerebral vascular endothelium and smooth muscle. Members of this channel superfamily show a wide variety of mechanisms ranging from ligand binding to voltage, physical, and chemical stimuli, implying the promising therapeutic potential of TRP in neurological diseases. In this review, we focus on the physiological functions of TRP channels in the brain and the pathological roles in neurological disorders to explore future potential neuroprotective strategies.
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TRPM4 Conductances in Thalamic Reticular Nucleus Neurons Generate Persistent Firing during Slow Oscillations. J Neurosci 2020; 40:4813-4823. [PMID: 32414784 DOI: 10.1523/jneurosci.0324-20.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/13/2020] [Accepted: 05/11/2020] [Indexed: 12/21/2022] Open
Abstract
During sleep, neurons in the thalamic reticular nucleus (TRN) participate in distinct types of oscillatory activity. While the reciprocal synaptic circuits between TRN and sensory relay nuclei are known to underlie the generation of sleep spindles, the mechanisms regulating slow (<1 Hz) forms of thalamic oscillations are not well understood. Under in vitro conditions, TRN neurons can generate slow oscillations in a cell-intrinsic manner, with postsynaptic Group 1 metabotropic glutamate receptor activation triggering long-lasting plateau potentials thought to be mediated by both T-type Ca2+ currents and Ca2+-activated nonselective cation currents (ICAN). However, the identity of ICAN and the possible contribution of thalamic circuits to slow rhythmic activity remain unclear. Using thalamic slices derived from adult mice of either sex, we recorded slow forms of rhythmic activity in TRN neurons, which were driven by fast glutamatergic thalamoreticular inputs but did not require postsynaptic Group 1 metabotropic glutamate receptor activation. For a significant fraction of TRN neurons, synaptic inputs or brief depolarizing current steps led to long-lasting plateau potentials and persistent firing (PF), and in turn, resulted in sustained synaptic inhibition in postsynaptic relay neurons of the ventrobasal thalamus (VB). Pharmacological approachesindicated that plateau potentials were triggered by Ca2+ influx through T-type Ca2+ channels and mediated by Ca2+- and voltage-dependent transient receptor potential melastatin 4 (TRPM4) channels. Together, our results suggest that thalamic circuits can generate slow oscillatory activity, mediated by an interplay of TRN-VB synaptic circuits that generate rhythmicity and TRN cell-intrinsic mechanisms that control PF and oscillation frequency.SIGNIFICANCE STATEMENT Slow forms of thalamocortical rhythmic activity are thought to be essential for memory consolidation during sleep and the efficient removal of potentially toxic metabolites. In vivo, thalamic slow oscillations are regulated by strong bidirectional synaptic pathways linking neocortex and thalamus. Therefore, in vitro studies in the isolated thalamus offer important insights about the ability of individual neurons and local circuits to generate different forms of rhythmic activity. We found that circuits formed by GABAergic neurons in the thalamic reticular nucleus and glutamatergic relay neurons in the ventrobasal thalamus generated slow oscillatory activity, which was accompanied by persistent firing in thalamic reticular nucleus neurons. Our results identify both cell-intrinsic and synaptic mechanisms that mediate slow forms of rhythmic activity in thalamic circuits.
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Hydrogen Peroxide Gates a Voltage-Dependent Cation Current in Aplysia Neuroendocrine Cells. J Neurosci 2019; 39:9900-9913. [PMID: 31676600 DOI: 10.1523/jneurosci.1460-19.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 10/07/2019] [Accepted: 10/27/2019] [Indexed: 11/21/2022] Open
Abstract
Nonselective cation channels promote persistent spiking in many neurons from a diversity of animals. In the hermaphroditic marine-snail, Aplysia californica, synaptic input to the neuroendocrine bag cell neurons triggers various cation channels, causing an ∼30 min afterdischarge of action potentials and the secretion of egg-laying hormone. During the afterdischarge, protein kinase C is also activated, which in turn elevates hydrogen peroxide (H2O2), likely by stimulating nicotinamide adenine dinucleotide phosphate oxidase. The present study investigated whether H2O2 regulates cation channels to drive the afterdischarge. In single, cultured bag cell neurons, H2O2 elicited a prolonged, concentration- and voltage-dependent inward current, associated with an increase in membrane conductance and a reversal potential of ∼+30 mV. Compared with normal saline, the presence of Ca2+-free, Na+-free, or Na+/Ca2+-free extracellular saline, lowered the current amplitude and left-shifted the reversal potential, consistent with a nonselective cationic conductance. Preventing H2O2 reduction with the glutathione peroxidase inhibitor, mercaptosuccinate, enhanced the H2O2-induced current, while boosting glutathione production with its precursor, N-acetylcysteine, or adding the reducing agent, dithiothreitol, lessened the response. Moreover, the current generated by the alkylating agent, N-ethylmaleimide, occluded the effect of H2O2 The H2O2-induced current was inhibited by tetrodotoxin as well as the cation channel blockers, 9-phenanthrol and clotrimazole. In current-clamp, H2O2 stimulated burst firing, but this was attenuated or prevented altogether by the channel blockers. Finally, H2O2 evoked an afterdischarge from whole bag cell neuron clusters recorded ex vivo by sharp-electrode. H2O2 may regulate a cation channel to influence long-term changes in activity and ultimately reproduction.SIGNIFICANCE STATEMENT Hydrogen peroxide (H2O2) is often studied in a pathological context, such as ischemia or inflammation. However, H2O2 also physiologically modulates synaptic transmission and gates certain transient receptor potential channels. That stated, the effect of H2O2 on neuronal excitability remains less well defined. Here, we examine how H2O2 influences Aplysia bag cell neurons, which elicit ovulation by releasing hormones during an afterdischarge. These neuroendocrine cells are uniquely identifiable and amenable to recording as individual cultured neurons or a cluster from the nervous system. In both culture and the cluster, H2O2 evokes prolonged, afterdischarge-like bursting by gating a nonselective voltage-dependent cationic current. Thus, H2O2, which is generated in response to afterdischarge-associated second messengers, may prompt the firing necessary for hormone secretion and procreation.
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Cáceres-Chávez VA, Hernández-Martínez R, Pérez-Ortega J, Herrera-Valdez MA, Aceves JJ, Galarraga E, Bargas J. Acute dopamine receptor blockade in substantia nigra pars reticulata: a possible model for drug-induced Parkinsonism. J Neurophysiol 2018; 120:2922-2938. [PMID: 30256736 DOI: 10.1152/jn.00579.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Dopamine (DA) depletion modifies the firing pattern of neurons in the substantia nigra pars reticulata (SNr), shifting their mostly tonic firing toward irregularity and bursting, traits of pathological firing underlying rigidity and postural instability in Parkinson's disease (PD) patients and animal models of Parkinsonism (PS). Drug-induced Parkinsonism (DIP) represents 20-40% of clinical cases of PS, becoming a problem for differential diagnosis, and is still not well studied with physiological tools. It may co-occur with tardive dyskinesia. Here we use in vitro slice preparations including the SNr to observe drug-induced pathological firing by using drugs that most likely produce it, DA-receptor antagonists (SCH23390 plus sulpiride), to compare with firing patterns found in DA-depleted tissue. The hypothesis is that SNr firing would be similar under both conditions, a prerequisite to the proposal of a similar preparation to test other DIP-producing drugs. Firing was analyzed with three complementary metrics, showing similarities between DA depletion and acute DA-receptor blockade. Moreover, blockade of either nonselective cationic channels or Cav3 T-type calcium channels hyperpolarized the membrane and abolished bursting and irregular firing, silencing SNr neurons in both conditions. Therefore, currents generating firing in control conditions are in part responsible for pathological firing. Haloperidol, a DIP-producing drug, reproduced DA-receptor antagonist firing modifications. Since acute DA-receptor blockade induces SNr neuron firing similar to that found in the 6-hydroxydopamine model of PS, output basal ganglia neurons may play a role in generating DIP. Therefore, this study opens the way to test other DIP-producing drugs. NEW & NOTEWORTHY Dopamine (DA) depletion enhances substantia nigra pars reticulata (SNr) neuron bursting and irregular firing, hallmarks of Parkinsonism. Several drugs, including antipsychotics, antidepressants, and calcium channel antagonists, among others, produce drug-induced Parkinsonism. Here we show the first comparison between SNr neuron firing after DA depletion vs. firing found after acute blockade of DA receptors. It was found that firing in both conditions is similar, implying that pathological SNr neuron firing is also a physiological correlate of drug-induced Parkinsonism.
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Affiliation(s)
| | - Ricardo Hernández-Martínez
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , México City, México
| | - Jesús Pérez-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México , Querétaro, México
| | - Marco Arieli Herrera-Valdez
- Departamento de Matemáticas, Facultad de Ciencias, Universidad Nacional Autónoma de México , México City, México
| | - Jose J Aceves
- Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán , Mexico City, México
| | - Elvira Galarraga
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , México City, México
| | - José Bargas
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México , México City, México
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Metaplasticity in the Visual Cortex: Crosstalk Between Visual Experience and Reactive Oxygen Species. J Neurosci 2018; 38:5649-5665. [PMID: 29789380 DOI: 10.1523/jneurosci.2617-17.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 04/17/2018] [Accepted: 05/12/2018] [Indexed: 01/18/2023] Open
Abstract
Metaplasticity is the regulation of synaptic plasticity based on the history of previous synaptic activation. This concept was formulated after observing that synaptic changes in the visual cortex are not fixed, but dynamic and dependent on the history of visual information flux. In visual cortical neurons, sustained synaptic stimulation activate the enzymatic complex NOX2, resulting in the generation of reactive oxygen species (ROS). NOX2 is the main molecular structure responsible for translating neural activity into redox modulation of intracellular signaling pathways involved in plastic changes. Here, we studied the interaction between NOX2 and visual experience as metaplastic factors regulating synaptic plasticity at the supergranular layers of the mouse visual cortex. We found that genetic inhibition of NOX2 reverses the polarizing effects of dark rearing from LTP to LTD. In addition, we demonstrate that this process relies on changes in the NMDA receptor functioning. Altogether, this work indicates a role of ROS in the activity-dependent regulation of cortical synaptic plasticity.SIGNIFICANCE STATEMENT Synaptic plasticity in the visual cortex is modulated by the history of sensory experience and this modulation has been defined as metaplasticity. Dark rearing facilitates synaptic potentiation as a mechanism optimizing the range of synaptic modification. This process requires the production of reactive oxygen species mediated by the enzymatic complex NOX2. If the activity of NOX2 is inhibited, then visual deprivation results in synaptic depression. These findings increase our knowledge about metaplasticity and help in our understanding of how neural activity modulates cellular mechanisms of synaptic change.
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19
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Belrose JC, Jackson MF. TRPM2: a candidate therapeutic target for treating neurological diseases. Acta Pharmacol Sin 2018; 39:722-732. [PMID: 29671419 PMCID: PMC5943913 DOI: 10.1038/aps.2018.31] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/24/2018] [Indexed: 12/25/2022] Open
Abstract
Transient receptor potential melastatin 2 (TRPM2) is a calcium (Ca2+)-permeable non-selective cation channel belonging to the TRP ion channel family. Oxidative stress-induced TRPM2 activation provokes aberrant intracellular Ca2+ accumulation and cell death in a variety of cell types, including neurons. Aberrant TRPM2 function has been implicated in several neurological disorders including ischemia/stroke, Alzheimer's disease, neuropathic pain, Parkinson's disease and bipolar disorder. In addition to research identifying a role for TRPM2 in disease, progress has been made in the identification of physiological functions of TRPM2 in the brain, including recent evidence that TRPM2 is necessary for the induction of N-methyl-D-aspartate (NMDA) receptor-dependent long-term depression, an important form of synaptic plasticity at glutamate synapses. Here, we summarize recent evidence on the role of TRPM2 in the central nervous system (CNS) in health and disease and discuss the potential therapeutic implications of targeting TRPM2. Collectively, these studies suggest that TRPM2 represents a prospective novel therapeutic target for neurological disorders.
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Affiliation(s)
- Jillian Corinne Belrose
- Department of Anesthesia & Perioperative Medicine, Schulich Medicine & Dentistry, Western University, London, Ontario, N6A 5A5, Canada
- E-mail
| | - Michael Frederick Jackson
- Department of Pharmacology and Therapeutics, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, R3E 0T6, Canada
- Neuroscience Research Program, Kleysen Institute for Advanced Medicine, Health Sciences Centre, Winnipeg, Manitoba, R3E 3J7, Canada
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Sun Y, Sukumaran P, Selvaraj S, Cilz NI, Schaar A, Lei S, Singh BB. TRPM2 Promotes Neurotoxin MPP +/MPTP-Induced Cell Death. Mol Neurobiol 2016; 55:409-420. [PMID: 27957685 DOI: 10.1007/s12035-016-0338-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 11/30/2016] [Indexed: 12/21/2022]
Abstract
In neurons, Ca2+ is essential for a variety of physiological processes that regulate gene transcription to neuronal growth and their survival. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridinium ions (MPP+) are potent neurotoxins that selectively destroys the dopaminergic (DA) neurons and mimics Parkinson's disease (PD) like symptoms, but the mechanism as how MPP+/MPTP effects DA neuron survival is not well-understood. In the present study, we found that MPP+ treatment increased the level of reactive oxygen species (ROS) that activates and upregulates the expression and function of melastatin-like transient receptor potential (TRPM) subfamily member, melastatin-like transient receptor potential channel 2 (TRPM2). Correspondingly, TRPM2 expression was also increased in substantia nigra of MPTP-induced PD mouse model and PD patients. ROS-mediated activation of TRPM2 resulted in an increased intracellular Ca2+, which in turn promoted cell death in SH-SY5Y cells. Intracellular Ca2+ overload caused by MPP+-induced ROS also affected calpain activity, followed by increased caspase 3 activities and activation of downstream apoptotic pathway. On the other hand, quenching of H2O2 by antioxidants, resveratrol (RSV), or N-acetylcysteine (NAC) effectively blocked TRPM2-mediated Ca2+ influx, decreased intracellular Ca2+ overload, and increased cell survival. Importantly, pharmacological inhibition of TRPM2 or knockdown of TRPM2 using siRNA, but not control siRNA, showed an increased protection by preventing MPP+-induced Ca2+ increase and inhibited apoptosis. Taken together, we show here a novel role for TRPM2 expression and function in MPP+-induced dopaminergic neuronal cell death.
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Affiliation(s)
- Yuyang Sun
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Pramod Sukumaran
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Senthil Selvaraj
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Nicholas I Cilz
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Anne Schaar
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Saobo Lei
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Brij B Singh
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA.
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Angioni L, Cocco C, Ferri GL, Argiolas A, Melis MR, Sanna F. Involvement of nigral oxytocin in locomotor activity: A behavioral, immunohistochemical and lesion study in male rats. Horm Behav 2016; 83:23-38. [PMID: 27189764 DOI: 10.1016/j.yhbeh.2016.05.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 04/21/2016] [Accepted: 05/13/2016] [Indexed: 01/27/2023]
Abstract
Oxytocin is involved in the control of different behaviors, from sexual behavior and food consumption to empathy, social and affective behaviors. An imbalance of central oxytocinergic neurotransmission has been also associated with different mental pathologies, from depression, anxiety and anorexia/bulimia to schizophrenia, autism and drug dependence. This study shows that oxytocin may also play a role in the control of locomotor activity. Accordingly, intraperitoneal oxytocin (0.5-2000μg/kg) reduced locomotor activity of adult male rats. This effect was abolished by d(CH2)5Tyr(Me)(2)-Orn(8)-vasotocin, an oxytocin receptor antagonist, given into the lateral ventricles at the dose of 2μg/rat, which was ineffective on locomotor activity. Oxytocin (50-200ng/site) also reduced and d(CH2)5Tyr(Me)(2)-Orn(8)-vasotocin (2μg/site) increased locomotor activity when injected bilaterally into the substantia nigra, a key area in the control of locomotor activity. Conversely, the destruction of nigral neurons bearing oxytocin receptors by the recently characterized neurotoxin oxytocin-saporin injected into the substantia nigra, increased basal locomotor activity. Since oxytocin-saporin injected into the substantia nigra caused a marked reduction of neurons immunoreactive for tyrosine hydroxylase (e.g., nigrostriatal dopaminergic neurons) and for vesicular glutamate transporters VGluT1, VGluT2 and VGluT3 (e.g., glutamatergic neurons), but not for glutamic acid decarboxylase (e.g., GABAergic neurons), together these findings suggest that oxytocin influences locomotor activity by acting on receptors localized presynaptically in nigral glutamatergic nerve terminals (which control the activity of nigral GABAergic efferent neurons projecting to brain stem nuclei controlling locomotor activity), rather than on receptors localized in the cell bodies/dendrites of nigrostriatal dopaminergic neurons.
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Affiliation(s)
- Laura Angioni
- Department of Biomedical Sciences, Section of Cytomorphology, NEF Laboratory, University of Cagliari, 09042 Monserrato (Cagliari), Italy
| | - Cristina Cocco
- Department of Biomedical Sciences, Section of Cytomorphology, NEF Laboratory, University of Cagliari, 09042 Monserrato (Cagliari), Italy
| | - Gian-Luca Ferri
- Department of Biomedical Sciences, Section of Cytomorphology, NEF Laboratory, University of Cagliari, 09042 Monserrato (Cagliari), Italy
| | - Antonio Argiolas
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, Neuropsychobiology Laboratory, University of Cagliari, 09042 Monserrato (Cagliari), Italy
| | - Maria Rosaria Melis
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, Neuropsychobiology Laboratory, University of Cagliari, 09042 Monserrato (Cagliari), Italy
| | - Fabrizio Sanna
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, Neuropsychobiology Laboratory, University of Cagliari, 09042 Monserrato (Cagliari), Italy.
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Lutas A, Lahmann C, Soumillon M, Yellen G. The leak channel NALCN controls tonic firing and glycolytic sensitivity of substantia nigra pars reticulata neurons. eLife 2016; 5. [PMID: 27177420 PMCID: PMC4902561 DOI: 10.7554/elife.15271] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/12/2016] [Indexed: 12/20/2022] Open
Abstract
Certain neuron types fire spontaneously at high rates, an ability that is crucial for their function in brain circuits. The spontaneously active GABAergic neurons of the substantia nigra pars reticulata (SNr), a major output of the basal ganglia, provide tonic inhibition of downstream brain areas. A depolarizing 'leak' current supports this firing pattern, but its molecular basis remains poorly understood. To understand how SNr neurons maintain tonic activity, we used single-cell RNA sequencing to determine the transcriptome of individual mouse SNr neurons. We discovered that SNr neurons express the sodium leak channel, NALCN, and that SNr neurons lacking NALCN have impaired spontaneous firing. In addition, NALCN is involved in the modulation of excitability by changes in glycolysis and by activation of muscarinic acetylcholine receptors. Our findings suggest that disruption of NALCN could impair the basal ganglia circuit, which may underlie the severe motor deficits in humans carrying mutations in NALCN. DOI:http://dx.doi.org/10.7554/eLife.15271.001 Some neurons in the brain produce electrical signals (or “fire”) spontaneously, without receiving any other signals from the senses or from other neurons. This spontaneous activity has a number of important roles. For example, in a part of the brain known as the substantia nigra pars reticulata (SNr), spontaneously active neurons frequently produce electrical signals that reduce electrical activity in other brain areas. A current of positively charged ions constantly flows into the spontaneously active SNr neurons and enables them to fire constantly. Ions enter neurons through proteins called ion channels that are embedded in the surface of the neuron. Like all proteins, ion channels are made by “transcribing” genes to form molecules of RNA that are then “translated” to produce the basic sequence of the protein. Lutas et al. have now used single-cell RNA sequencing to study SNr neurons from mice and investigate which ion channel the positive ion current flows through. The RNA sequences revealed that the neurons have the gene for an ion channel known as NALCN. Recordings of the firing rate of neurons in slices of mouse brain showed that SNr neurons without this channel did not fire as often as SNr neurons with the channel. In addition, neurotransmitters (chemicals that alter the ability of neurons to fire) and changes in cell metabolism had less of an effect on the firing rate of SNr neurons that lacked the NALCN channel than they do on normal neurons. These findings may help explain why people with mutations in the NALCN gene have movement disorders, as the substantia nigra pars reticulata plays an important role in orchestrating complex movements. Future work is now needed to understand how a change in NALCN activity affects the other brain areas that SNr neurons connect to. DOI:http://dx.doi.org/10.7554/eLife.15271.002
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Affiliation(s)
- Andrew Lutas
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Carolina Lahmann
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | | | - Gary Yellen
- Department of Neurobiology, Harvard Medical School, Boston, United States
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Ohashi M, Hirano T, Watanabe K, Katsumi K, Ohashi N, Baba H, Endo N, Kohno T. Hydrogen peroxide modulates synaptic transmission in ventral horn neurons of the rat spinal cord. J Physiol 2016; 594:115-34. [PMID: 26510999 PMCID: PMC4704504 DOI: 10.1113/jp271449] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 10/16/2015] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Excessive production of reactive oxygen species (ROS) is implicated in many central nervous system disorders; however, the physiological role of ROS in spinal ventral horn (VH) neurons remains poorly understood. We investigated how pathological levels of H2O2, an abundant ROS, regulate synaptic transmission in VH neurons of rats using a whole-cell patch clamp approach. H2O2 increased the release of glutamate and GABA from presynaptic terminals. The increase in glutamate release involved N-type voltage-gated calcium channels (VGCCs), ryanodine receptors (RyRs), and inositol trisphosphate receptors (IP3 Rs); the increase in GABA release, which inhibited glutamatergic transmission, involved IP3 R. Inhibiting N-type VGCCs and RyRs attenuates excitotoxicity resulting from increased glutamatergic activity while preserving the neuroprotective effects of GABA, and may represent a novel strategy for treating H2O2-induced motor neuron disorders resulting from trauma or ischaemia-reperfusion injury. Excessive production of reactive oxygen species (ROS) is a critical component of the cellular and molecular pathophysiology of many central nervous system (CNS) disorders, including trauma, ischaemia-reperfusion injury, and neurodegenerative diseases. Hydrogen peroxide (H2O2), an abundant ROS, modulates synaptic transmission and contributes to neuronal damage in the CNS; however, the pathophysiological role of H2O2 in spinal cord ventral horn (VH) neurons remains poorly understood, despite reports that these neurons are highly vulnerable to oxidative stress and ischaemia. This was investigated in the present study using a whole-cell patch clamp approach in rats. We found that exogenous application of H2O2 increased the release of glutamate from excitatory presynaptic terminals and γ-aminobutyric acid (GABA) from inhibitory presynaptic terminals. The increase of glutamate release was induced in part by an increase in Ca(2+) influx through N-type voltage-gated calcium channels (VGCCs) as well as by ryanodine receptor (RyR)- and inositol trisphosphate receptor-mediated Ca(2+) release from the endoplasmic reticulum (ER). In inhibitory presynaptic neurons, increased IP3 R-mediated Ca(2+) release from the ER increased GABAergic transmission, which served to rescue VH neurons from excessive release of glutamate from presynaptic terminals. These findings indicate that inhibiting N-type VGCCs or RyRs may attenuate excitotoxicity resulting from increased glutamatergic activity while preserving the neuroprotective effects of GABA, and may therefore represent a novel and targeted strategy for preventing and treating H2O2-induced motor neuron disorders.
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Affiliation(s)
- Masayuki Ohashi
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Toru Hirano
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Kei Watanabe
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Keiichi Katsumi
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Nobuko Ohashi
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Hiroshi Baba
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Naoto Endo
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
| | - Tatsuro Kohno
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City 951-8510, Japan
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25
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Bowie D, Attwell D. Coupling cellular metabolism to neuronal signalling. J Physiol 2015; 593:3413-5. [PMID: 26272625 DOI: 10.1113/jp271075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 06/19/2015] [Indexed: 01/15/2023] Open
Affiliation(s)
- Derek Bowie
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada, H3G 1Y6
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK
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Burst pacemaker activity of the sinoatrial node in sodium-calcium exchanger knockout mice. Proc Natl Acad Sci U S A 2015. [PMID: 26195795 DOI: 10.1073/pnas.1505670112] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In sinoatrial node (SAN) cells, electrogenic sodium-calcium exchange (NCX) is the dominant calcium (Ca) efflux mechanism. However, the role of NCX in the generation of SAN automaticity is controversial. To investigate the contribution of NCX to pacemaking in the SAN, we performed optical voltage mapping and high-speed 2D laser scanning confocal microscopy (LSCM) of Ca dynamics in an ex vivo intact SAN/atrial tissue preparation from atrial-specific NCX knockout (KO) mice. These mice lack P waves on electrocardiograms, and isolated NCX KO SAN cells are quiescent. Voltage mapping revealed disorganized and arrhythmic depolarizations within the NCX KO SAN that failed to propagate into the atria. LSCM revealed intermittent bursts of Ca transients. Bursts were accompanied by rising diastolic Ca, culminating in long pauses dominated by Ca waves. The L-type Ca channel agonist BayK8644 reduced the rate of Ca transients and inhibited burst generation in the NCX KO SAN whereas the Ca buffer 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (acetoxymethyl ester) (BAPTA AM) did the opposite. These results suggest that cellular Ca accumulation hinders spontaneous depolarization in the NCX KO SAN, possibly by inhibiting L-type Ca currents. The funny current (If) blocker ivabradine also suppressed NCX KO SAN automaticity. We conclude that pacemaker activity is present in the NCX KO SAN, generated by a mechanism that depends upon If. However, the absence of NCX-mediated depolarization in combination with impaired Ca efflux results in intermittent bursts of pacemaker activity, reminiscent of human sinus node dysfunction and "tachy-brady" syndrome.
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Ibáñez-Sandoval O, Xenias HS, Tepper JM, Koós T. Dopaminergic and cholinergic modulation of striatal tyrosine hydroxylase interneurons. Neuropharmacology 2015; 95:468-76. [PMID: 25908399 DOI: 10.1016/j.neuropharm.2015.03.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 03/17/2015] [Accepted: 03/31/2015] [Indexed: 10/23/2022]
Abstract
The recent electrophysiological characterization of TH-expressing GABAergic interneurons (THINs) in the neostriatum revealed an unexpected degree of diversity of interneurons in this brain area (Ibáñez-Sandoval et al., 2010, Unal et al., 2011, 2015). Despite being relatively few in number, THINs may play a significant role in transmitting and distributing extra- and intrastriatal neuromodulatory signals in the striatal circuitry. Here we investigated the dopaminergic and cholinergic regulation of THINs in vitro. We found that the dominant effect of dopamine was a dramatic enhancement of the ability of THINs to generate long-lasting depolarizing plateau potentials (PPs). Interestingly, the same effect could also be elicited by amphetamine-induced release of endogenous dopamine suggesting that THINs may exhibit similar responses to changes in extracellular dopamine concentration in vivo. The enhancement of PPs in THINs is perhaps the most pronounced effect of dopamine on the intrinsic excitability of neostriatal neurons described to date. Further, we demonstrate that all subtypes of THINSs tested also express nicotinic cholinergic receptors. All THIS responded, albeit differentially, with depolarization, PPs and spiking to brief application of nicotinic agonists. Powerful modulation of the nonlinear integrative properties of THINs by dopamine and the direct depolarization of these neurons by acetylcholine may play important roles in mediating the effects of these neuromodulators in the neostriatum with potentially important implications for understanding the mechanisms of neuropsychiatric disorders affecting the basal ganglia.
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Affiliation(s)
- Osvaldo Ibáñez-Sandoval
- Center for Molecular and Behavioral Neuroscience, Rutgers The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA
| | - Harry S Xenias
- Center for Molecular and Behavioral Neuroscience, Rutgers The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA
| | - James M Tepper
- Center for Molecular and Behavioral Neuroscience, Rutgers The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA.
| | - Tibor Koós
- Center for Molecular and Behavioral Neuroscience, Rutgers The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA.
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28
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Lee CR, Patel JC, O'Neill B, Rice ME. Inhibitory and excitatory neuromodulation by hydrogen peroxide: translating energetics to information. J Physiol 2015; 593:3431-46. [PMID: 25605547 DOI: 10.1113/jphysiol.2014.273839] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/16/2015] [Indexed: 12/21/2022] Open
Abstract
Historically, brain neurochemicals have been broadly classified as energetic or informational. However, increasing evidence implicates metabolic substrates and byproducts as signalling agents, which blurs the boundary between energy and information, and suggests the introduction of a new category for 'translational' substances that convey changes in energy state to information. One intriguing example is hydrogen peroxide (H2 O2 ), which is a small, readily diffusible molecule. Produced during mitochondrial respiration, this reactive oxygen species, can mediate dynamic regulation of neuronal activity and transmitter release by activating inhibitory ATP-sensitive K(+) (KATP ) channels, as well as a class of excitatory non-selective cation channels, TRPM2. Studies using ex vivo guinea pig brain slices have revealed that activity-generated H2 O2 can act via KATP channels to inhibit dopamine release in dorsal striatum and dopamine neuron activity in the substantia nigra pars compacta. In sharp contrast, endogenously generated H2 O2 enhances the excitability of GABAergic projection neurons in the dorsal striatum and substantia nigra pars reticulata by activating TRPM2 channels. These studies suggest that the balance of excitation vs. inhibition produced in a given cell by metabolically generated H2 O2 will be dictated by the relative abundance of H2 O2 -sensitive ion channel targets that receive this translational signal.
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Affiliation(s)
- Christian R Lee
- Department of Neurosurgery, New York University School of Medicine, New York, NY, 10016, USA
| | - Jyoti C Patel
- Department of Neurosurgery, New York University School of Medicine, New York, NY, 10016, USA
| | - Brian O'Neill
- Department of Neurosurgery, New York University School of Medicine, New York, NY, 10016, USA.,Department of Psychiatry, New York University School of Medicine, New York, NY, 10016, USA
| | - Margaret E Rice
- Department of Neurosurgery, New York University School of Medicine, New York, NY, 10016, USA.,Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, 10016, USA
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Metabolism regulates the spontaneous firing of substantia nigra pars reticulata neurons via KATP and nonselective cation channels. J Neurosci 2015; 34:16336-47. [PMID: 25471572 DOI: 10.1523/jneurosci.1357-14.2014] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Neurons use glucose to fuel glycolysis and provide substrates for mitochondrial respiration, but neurons can also use alternative fuels that bypass glycolysis and feed directly into mitochondria. To determine whether neuronal pacemaking depends on active glucose metabolism, we switched the metabolic fuel from glucose to alternative fuels, lactate or β-hydroxybutyrate, while monitoring the spontaneous firing of GABAergic neurons in mouse substantia nigra pars reticulata (SNr) brain slices. We found that alternative fuels, in the absence of glucose, sustained SNr spontaneous firing at basal rates, but glycolysis may still be supported by glycogen in the absence of glucose. To prevent any glycogen-fueled glycolysis, we directly inhibited glycolysis using either 2-deoxyglucose or iodoacetic acid. Inhibiting glycolysis in the presence of alternative fuels lowered SNr firing to a slower sustained firing rate. Surprisingly, we found that the decrease in SNr firing was not mediated by ATP-sensitive potassium (KATP) channel activity, but if we lowered the perfusion flow rate or omitted the alternative fuel, KATP channels were activated and could silence SNr firing. The KATP-independent slowing of SNr firing that occurred with glycolytic inhibition in the presence of alternative fuels was consistent with a decrease in a nonselective cationic conductance. Although mitochondrial metabolism alone can prevent severe energy deprivation and KATP channel activation in SNr neurons, active glucose metabolism appears important for keeping open a class of ion channels that is crucial for the high spontaneous firing rate of SNr neurons.
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Abstract
SIGNIFICANCE There is increasing evidence that the generation of reactive oxygen species (ROS) in the central nervous system (CNS) involves the NOX family of nicotinamide adenine dinucleotide phosphate oxidases. Controlled ROS generation appears necessary for optimal functioning of the CNS through fine-tuning of redox-sensitive signaling pathways, while overshooting ROS generation will lead to oxidative stress and CNS disease. RECENT ADVANCES NOX enzymes are not only restricted to microglia (i.e. brain phagocytes) but also expressed in neurons, astrocytes, and the neurovascular system. NOX enzymes are involved in CNS development, neural stem cell biology, and the function of mature neurons. While NOX2 appears to be a major source of pathological oxidative stress in the CNS, other NOX isoforms might also be of importance, for example, NOX4 in stroke. Globally speaking, there is now convincing evidence for a role of NOX enzymes in various neurodegenerative diseases, cerebrovascular diseases, and psychosis-related disorders. CRITICAL ISSUES The relative importance of specific ROS sources (e.g., NOX enzymes vs. mitochondria; NOX2 vs. NOX4) in different pathological processes needs further investigation. The absence of specific inhibitors limits the possibility to investigate specific therapeutic strategies. The uncritical use of non-specific inhibitors (e.g., apocynin, diphenylene iodonium) and poorly validated antibodies may lead to misleading conclusions. FUTURE DIRECTIONS Physiological and pathophysiological studies with cell-type-specific knock-out mice will be necessary to delineate the precise functions of NOX enzymes and their implications in pathomechanisms. The development of CNS-permeant, specific NOX inhibitors will be necessary to advance toward therapeutic applications.
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Affiliation(s)
- Zeynab Nayernia
- 1 Department of Pathology and Immunology, Geneva Medical Faculty, Geneva University Hospitals, Centre Médical Universitaire , Geneva, Switzerland
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31
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Moreau C, Kirchberger T, Swarbrick JM, Bartlett SJ, Fliegert R, Yorgan T, Bauche A, Harneit A, Guse AH, Potter BVL. Structure-activity relationship of adenosine 5'-diphosphoribose at the transient receptor potential melastatin 2 (TRPM2) channel: rational design of antagonists. J Med Chem 2013; 56:10079-102. [PMID: 24304219 PMCID: PMC3873810 DOI: 10.1021/jm401497a] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Adenosine
5′-diphosphoribose (ADPR) activates TRPM2, a Ca2+, Na+, and K+ permeable cation channel.
Activation is induced by ADPR binding to the cytosolic C-terminal
NudT9-homology domain. To generate the first structure–activity
relationship, systematically modified ADPR analogues were designed,
synthesized, and evaluated as antagonists using patch-clamp experiments
in HEK293 cells overexpressing human TRPM2. Compounds with a purine C8 substituent show antagonist activity, and an 8-phenyl
substitution (8-Ph-ADPR, 5) is very effective. Modification
of the terminal ribose results in a weak antagonist, whereas its removal
abolishes activity. An antagonist based upon a hybrid structure, 8-phenyl-2′-deoxy-ADPR
(86, IC50 = 3 μM), is more potent than
8-Ph-ADPR (5). Initial bioisosteric replacement of the
pyrophosphate linkage abolishes activity, but replacement of the pyrophosphate
and the terminal ribose by a sulfamate-based group leads to a weak
antagonist, a lead to more drug-like analogues. 8-Ph-ADPR (5) inhibits Ca2+ signalling and chemotaxis in human neutrophils,
illustrating the potential for pharmacological intervention at TRPM2.
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Affiliation(s)
- Christelle Moreau
- Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom
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Shabani M, Mahnam A, Sheibani V, Janahmadi M. Alterations in the Intrinsic Burst Activity of Purkinje Neurons in Offspring Maternally Exposed to the CB1 Cannabinoid Agonist WIN 55212-2. J Membr Biol 2013; 247:63-72. [DOI: 10.1007/s00232-013-9612-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 10/25/2013] [Indexed: 11/28/2022]
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Tran VT, Ho PT, Cabrera L, Torres JE, Bhattacharya SK. Mechanotransduction channels of the trabecular meshwork. Curr Eye Res 2013; 39:291-303. [PMID: 24215462 DOI: 10.3109/02713683.2013.842593] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE To determine whether the trabecular meshwork (TM), like the other organs engaged in filter like activities (such as kidneys), show the expression of known mechanotransduction channels at protein level. METHODS Human donor eye globes (n = 20), Donor eye derived TM tissue and primary TM cells were utilized for these studies. Commercially available antibodies to channels, immunohisto- and immunocytochemistry, Western blot and mass spectrometric analyses were performed to determine the presence of mechanosensitive channels at protein level. The study was performed adhering to tenets of declaration of Helsinki. RESULTS We demonstrate here the presence of 11 mechanotransduction channels (Piezo1, Piezo2, TASK1, TREK1, TRPA1, TRPC1, TRPC2, TRPC3, TRPC6, TRPM2, TRPP2) as expressed protein in the TM tissue and at the isolated TM cell level. Presence of at least one known isoform of these channels was demonstrated using Western blot analyses. CONCLUSIONS We demonstrated the presence of 11 mechanotransduction channels in the TM and in isolated TM cells at protein level. Demonstration of these channels as proteins at tissue and cellular level will pave the way for further experimentation.
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Affiliation(s)
- Vu T Tran
- Bascom Palmer Eye Institute, University of Miami , Miami, FL , USA
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Patel JC, Rice ME. Classification of H₂O₂as a neuromodulator that regulates striatal dopamine release on a subsecond time scale. ACS Chem Neurosci 2012; 3:991-1001. [PMID: 23259034 DOI: 10.1021/cn300130b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 10/15/2012] [Indexed: 01/18/2023] Open
Abstract
Here we review evidence that the reactive oxygen species, hydrogen peroxide (H(2)O(2)), meets the criteria for classification as a neuromodulator through its effects on striatal dopamine (DA) release. This evidence was obtained using fast-scan cyclic voltammetry to detect evoked DA release in striatal slices, along with whole-cell and fluorescence imaging to monitor cellular activity and H(2)O(2) generation in striatal medium spiny neurons (MSNs). The data show that (1) exogenous H(2)O(2) suppresses DA release in dorsal striatum and nucleus accumbens shell and the same effect is seen with elevation of endogenous H(2)O(2) levels; (2) H(2)O(2) is generated downstream from glutamatergic AMPA receptor activation in MSNs, but not DA axons; (3) generation of modulatory H(2)O(2) is activity dependent; (4) H(2)O(2) generated in MSNs diffuses to DA axons to cause transient DA release suppression by activating ATP-sensitive K(+) (K(ATP)) channels on DA axons; and (5) the amplitude of H(2)O(2)-dependent inhibition of DA release is attenuated by enzymatic degradation of H(2)O(2), but the subsecond time course is determined by H(2)O(2) diffusion rate and/or K(ATP)-channel kinetics. In the dorsal striatum, neuromodulatory H(2)O(2) is an intermediate in the regulation of DA release by the classical neurotransmitters glutamate and GABA, as well as other neuromodulators, including cannabinoids. However, modulatory actions of H(2)O(2) occur in other regions and cell types, as well, consistent with the widespread expression of K(ATP) and other H(2)O(2)-sensitive channels throughout the CNS.
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Affiliation(s)
- Jyoti C. Patel
- Department
of Neurosurgery, ‡Department of Physiology and Neuroscience, New York University School of Medicine, 550 First Avenue,
New York, New York 10016, United States
| | - Margaret E. Rice
- Department
of Neurosurgery, ‡Department of Physiology and Neuroscience, New York University School of Medicine, 550 First Avenue,
New York, New York 10016, United States
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